Manual of Recycling: Gebäude als Materialressource / Buildings as sources of materials 9783955534936, 9783955534929

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Manual of Recycling Buildings as Sources of Materials

Annette Hillebrandt Petra Riegler-Floors Anja Rosen Johanna-Katharina Seggewies

Edition ∂

Authors Annette Hillebrandt Univ.- Prof. Dipl.-Ing. Architect Petra Riegler-Floors Dipl.-Ing. Architect Anja Rosen M. A. Architect Johanna-Katharina Seggewies M. Sc. M. A.

With specialist contributions from: Prof. Dr. Günther Bachmann Council for Sustainable Development, Berlin Prof. Dipl.-Ing. Markus Binder Hochschule für Technik Stuttgart, Department of Integrated Building Technology, CAPE climate architecture physics energy, Esslingen / Schwäbisch Hall Univ.- Prof. Dr.-Ing. Manfred Helmus Bergische Universität Wuppertal, Academic and research field of Construction Operations and Industry

Research assistant: Julia Blasius, M. Sc.

Univ.- Prof. Holger Hoffmann Bergische Universität Wuppertal, Professor of Representational Methodology and Design

All authors engaged at: Bergische Universität Wuppertal, Faculty of Architecture and Civil Engineering, Department of Structure I Design I Material Studies Research focus: Loop potential of constructions and materials in architecture

Dipl.-Ing. Mag. Thomas Kasper Porr Umwelttechnik GmbH, Vienna Dipl.-Ing. Holger Kesting Bergische Universität Wuppertal, Academic and research field of Construction Operations and Industry Dipl.-Ing. Architect Thomas Matthias Romm forschen planen bauen, Vienna Dipl.-Ing. Michael Wengert, B. Eng. Tobias Edelmann Pfeil + Koch ingenieurgesellschaft, Stuttgart

Editorial services Editing, copy editing (German edition): Steffi Lenzen (Project Manager), Jana Rackwitz, Daniel Reisch; Carola Jacob-Ritz (Proofreading) Drawings: Marion Griese, Ralph Donhauser Translation into English: Susanne Hauger, New York Christina McKenna (Part A and B2), Berlin Copy editing (English edition): Stefan Widdess, Berlin Proofreading (English edition): Thomas Cullen, Olching Cover design: Wiegand von Hartmann GbR, München Production and DTP: Roswitha Siegler, Simone Soesters Reproduction: ludwig:media, Zell am See Printing and binding: Grafisches Centrum Cuno GmbH & Co. KG, Calbe © 2019 English translation of the 1st German edition “Atlas Recycling” (ISBN: 978-3-95553-415-8) 2

Publisher: Detail Business Information GmbH, Munich detail-online.com ISBN: 978-3-95553-492-9 (printed edition) ISBN: 978-3-95553-493-6 (e-book) Bibliographic information published by the German National ­ ibrary. The German National Library lists this publication in the L German National Bibliography (Deutsche Nationalbibliografie); detailed bibliographic data are available on the Internet at http://dnb.d-nb.de. This work is subject to copyright. All rights reserved. These rights specifically include the rights of translation, reprinting, and presentation, the reuse of illustrations and tables, broadcasting, reproduction on microfilm or on any other media and storage in data processing systems. Furthermore, these rights pertain to any and all parts of the material. Any reproduction of this work, whether in whole or in part, even in individual cases, is only permitted within the scope specified by the applicable copyright law. Any reproduction is subject to charges. Any infringement will be subject to the penalty clauses of copyright law. This textbook uses terms applicable at the time of writing and is based on the current state of the art, to the best of the authors’ and editors’ knowledge and belief. All drawings in this book were made specifically by the publisher. No legal claims can be derived from the contents of this book.

Contents

Motivation4 6 Urban Resource Exploration – Producing Structures in Closed-Loop Materials Cycles Part A  Strategies and Potential 1  2  3  4  5  6 

Circularity in Architecture – Urban Mining Design Dismantling, Recovery and Disposal in Construction An Overview of Rating Systems Using BIM to Optimise Materials Cycles in Construction An Elastic Standard – Urban Mining and Computational Design Eco-Efficient Construction Using Local Resources

10 16 24 32 34 36

Part B  Construction and Materials 1  Detachable Connections and Constructions 2  The Recycling Potential of Building Materials 3  Mono-Material Construction 4 Can Loop Potential Be Measured? An Analysis Using Facade and Roof Coverings as Examples 5  Assessment of Loop Potential 6  Challenges in the Structural Design of Dismantling- and Recycling-Friendly Constructions 7  Cost Comparisons of Conventional and Urban Mining Design Constructions

42 58 102 108 114 118 120

Part C  Detailed Catalogue Overview of Examples 01 to 09

135

Part D  Completed Examples Overview of Examples 01 to 21

179

Appendix Authors214 Project Participants 215 Glossary216 Picture Credits 220 Subject Index 222 Supporters / Sponsors 224 3

Motivation

It takes three years to build a good house. If it is sustainable, it will be valued by both its inhabitants and its visitors. However, in the scheme of things, the impact of a single house is limited. It also took three years to write this book. We hope to reach the many architects who are convinced of the urgent need for a paradigm shift in building, and that these architects will then go on to build many better houses – in order to change the scheme of things before it is too late.

Our motivation for writing this book, in the words of others:

“RESOURCE EFFICIENCY HAS TAKEN CENTRE STAGE IN THE INTERNATIONAL POLICY DEBATE” Global Material Flows and Resource Productivity, United Nations Environment Programme (UNEP), 2016

Resource consumption “The construction and use of buildings in the EU account for about 50 % of all our extracted resource and ­energy consumption, as well as about a third of our water consumption.”

We are faced with a major challenge that ­represents a society-wide, global necessity. We see this as an opportunity to take a new, concept-based architectural stance that puts a new sense of responsibility at the forefront of every aesthetic debate.

Report by the commission to the European Parliament (… on the efficient use of resources in the building sector), Brussels 2014

In the course of an 80-year lifetime, a person in Germany uses about 530 tonnes of sand, gravel, granite and limestone and approximately 40 tonnes of steel. MaRess, Resource Efficiency Paper 3.7, Wuppertal Institute for Climate, Environment and Energy GmbH and Leuphana University Lüneburg, Wuppertal 2010

Urban Mining Design is not intended to be a new style of building, but a new paradigm: Waste is a design flaw!

“What will the plundering of the Earth lead to in all the coming centuries? How far will our greed drive us?”

German Basic Law, Article 20 a: “Mindful also of its responsibility toward future generations, the state shall protect the natural foundations of life (...)” Why wait for that? We already have the know-how, so let’s use it! With many thanks to our sponsors and to all of our collaborators who supported us with their knowledge and their lifetime efforts.

Gaius Plinius Secundus Major (the Elder), Roman scholar, died 79 CE

Waste “… A MINORITY BELIEVES THAT IT HAS THE RIGHT TO CONSUME IN A WAY WHICH CAN NEVER BE UNIVERSALISED, SINCE THE PLANET COULD NOT EVEN CONTAIN THE WASTE PRODUCTS OF SUCH CONSUMPTION.” Pope Francis, Laudato Si’ Second Encyclical 2015

In 2014, 52 % of all wastes were attributable to the building sector. A four-member family generated 28.3 kg of construction waste per day in 2014, of which 1.01 kg were hazardous materials. Federal Statistical Office (Destatis), Environment, Waste Balance 2014, Wiesbaden 2016

August 2018 Annette Hillebrandt, Petra Riegler-Floors, Anja Rosen, Johanna-Katharina Seggewies

4

“WASTE IS NOURISHMENT”

Michael Braungart, brandeins, 2008

Resource scarcity and landfill limits The EU can only cover about 9 % of its raw materials needs from its own sources. For critical materials the self-supplied proportion is assumed to be under 3 %. European Commission: Report on critical raw materials for the EU – Ad hoc Working Group, 2014

“CREATIVE APPROACHES WILL BE NEEDED THAT ADDRESS THE WAY GERMANY SHOULD DEAL WITH THE EXPECTED RESOURCE BOTTLENECKS AND EXPENSIVE IMPORTS OF THE FUTURE.” Federal Environmental Agency: “raw materials sources right in front of us (Urban Mining – Rohstoffquellen direkt vor der Tür)”, press release No. 30, 2017

“Waste disposal in landfills is especially damaging to the ecosystem and the climate. For this reason, landfill use should be available for at most 5 % of all wastes by 2030.” Jo Leinen, Member of the European Parliament, Brussels 2017

Paradigm shift “Therefore the greatest art/science/diligence and arrangement in these lands will lie / in the establishment of such a conservation and cultivation of wood / that there will be a continuous enduring and sustainable use / because it is an indispensable thing / without which the country would not want to remain in existence.” Carl von Carlowitz: Sylvicultura Oeconomica 1713

“MANY ARE OF THE OPINION THAT THE FUTURE FATE OF MANKIND (…) DEPENDS ON HOW QUICKLY AND HOW EFFECTIVELY PROBLEMS ARE SOLVED THROUGHOUT THE WORLD. NONETHELESS, ONLY A TINY FRACTION OF MANKIND IS ACTIVELY ENGAGED (…) IN THE SEARCH FOR SOLUTIONS.” Dennis Meadows: Limits to Growth – Club of Rome report on the situation of mankind, 1972

“Ephemeral construction!” [a renunciation of the concept of an architecture for all eternity] Werner Sobek “Das beste System auf dem Globus”, Deutsches Architektenblatt, 2009

“(...) IN LIGHT OF ECOLOGICAL LIMITS THERE CAN AND SHOULD BE NO NEW GROWTH CYCLE BASED ON YET MORE CONSUMPTION OF ENERGY, WATER AND MINERALS. THE NEW CYCLE MUST BE ‘GREEN’ (…)” Ernst Ulrich von Weizsäcker, FAKTOR FÜNF, 2009

“If we do not find a path to sustainable growth, (…) we will pay for it in the next crisis.” German Chancellor Angela Merkel, budget debate, Berlin 21 June 2010

5

Urban Resource Exploration – Producing ­Structures in Closed-Loop Materials Cycles Günther Bachmann

In 1933, the Athens Charter called for work­ places and residences in cities to be spatially separated. This was urgently needed at the time and proved a great success for architects and urban planners. The resulting cleaner air and noise reduction improved many people’s health. Technical environmental protection is now very advanced in industrialised coun­ tries, albeit at varying levels with some persist­ ent deficits, and the construction industry is currently grappling with a new and more farreaching idea of separation. Separate material streams will be necessary if the environmental goal of recovering and recycling building ma­terials and valuable substances from city buildings is to be achieved.

Notes: [1] cf. UN Habitat, https://unhabitat.org/united-nationsadopts-sdgs-cities-in-greater-focus/ and FAO Food for the Cities multidisciplinary initiative (Pub.): Chal­ lenges of food and nutrition security, agriculture and ecosystem management in an urbanizing world. http://www.fao.org/3/a-au725e.pdf (August 2017) [2] Friege, Henning: Ressourcenmanagement und Sied­ lungsabfallwirtschaft. Challenger Report für den Rat für Nachhaltige Entwicklung. texte Nr. 48, 01/2015, https://www.nachhaltigkeitsrat.de/wp-content/up­ loads/migration/documents/Challenger_Report_Res­ sourcenmanagement_und_Siedlungsabfallwirtschaft_ texte_Nr_48_Januar_2015.pdf. As of 13.06.2018 [3] Rat für Nachhaltige Entwicklung – RNE (Pub.): Indus­ trie 4.0 und Nachhaltigkeit. Chancen und Risiken für die Nachhaltige Entwicklung. Report. Berlin 2016 https://www.nachhaltigkeitsrat.de/wp-content/uploads/ migration/documents/20161230_IFOK_Bericht_­ Industrie_4-0_und_Nachhaltige_Entwicklung.pdf. As of 13.06.2018 [4] see also www.deutscher-nachhaltigkeitskodex.de/ en-gb [5] Rat für Nachhaltige Entwicklung und Accenture Strat­ egy Sustainability, in cooperation with the Ökopol ­Institut für Ökologie und Politik GmbH: Chancen der Kreislaufwirtschaft für Deutschland. Analyse von ­Potenzialen und Ansatzpunkten für die IKT-, Auto­ mobil- und Baustoffindustrie. Hamburg. Berlin 2017 https://www.nachhaltigkeitsrat.de/wp-content/up­ loads/migration/documents/RNE-Accenture_Studie_ Chancen_der_Kreislaufwirtschaft_04-07-2017.pdf. As of 13.06.2018

6

The United Nations Sustainable Development Goals (SDGs), which were adopted in 2015, provide important impetus for resetting this ­‘circular economy’. Germany was involved in drafting the goals and is implementing them at national level in its Sustainable Devel­ opment Strategy. The SDGs are to today’s ­sustainability policy what the Athens Charter was to urban planning in its day: a concise, contemporary description of the tasks required. They call for the launch of an ambitious circular economy, a zero-tolerance strategy in dealing with soil pollution, Land Degradation Neutrality (LDN) and sustainable urban development. And rightly so: Half the people on Earth now live in urban agglomerations for which the word “city” would be a euphemism. In 10 years’ time, this figure will have risen to 60 % and by the middle of the century to 80 % of the world’s projected population of 9 –10 billion people. 828 million people now live in slums and their number is growing. ­Cities are hotspots of envi­ ronmental resource consumption. All over the world they have been built on valuable agricul­ tural land, pushing food production out to less productive marginal areas. Cities use up 80 % of the world’s energy [1]. The greatest pressure these problems impose is felt in cities in nations formerly referred to as ‘developing countries’, although the greatest pressure for development is felt not there, but

in highly-developed industrialised countries. Whether we see this as contingent on history, as part of a wider responsibility and ethical approach, or as resulting from the economic efficiency that technical innovation has created, we must succeed in launching a new era, which sees the city as a mine for raw materials. cities for raw materials. The word “mine” may create misleading images and analogies, but it needs to be seen in a new, innovative context. Every mining venture starts with planning and exploration and this is just as true of cities. The goal of efficient raw ma­terials usage can be achieved by avoiding and reducing waste, making repairs and ­ensuring durability, reusing and recycling. It will require changes to prod­ uct design, ­circular economic processes and responsible ownership, and it will take new materials and redesign as well as changes to users’ behaviour and practices that reduce the use of materials in construction. ‘Urban mining’, which regards a city as a huge repository of raw materials, is in fact more like urban resources exploration. ‘Urban mining’ is a term that epitomises the city of tomorrow. It links a wide-ranging per­ spective with creative drive and this must be particularly emphasised, with useful and scal­ able instruments that already exist. These include those for quantifying secondary raw materials, recovery and recycling techniques, the digi­t­alisation of recycling patterns in ­structural ­information, profitability analyses, and business sectors such as those that ­process and recover valuable materials. Local, self-­contained closed-loop circulation of build­ ing materials would not be healthy or rational, would impede innovation and have strongly ideological traits. The future of the city lies in decentralised inte­ gration, in social mobility and in complicated and seemingly utopian tasks such as the reurbanisation of food production, which has long since begun. One fundamental prerequisite for all this is becoming increasingly clear: cities must learn to renew themselves. They need to link their energy supplies, mobility infrastruc­ ture and elements of their food supplies, all of

Urban Resource Exploration – Producing ­Structures in Closed-Loop Materials Cycles

which will require a focus on the materials used to build cities. In contrast, “imperial” approaches allow cities to continue obtaining their building ­materials from all over the world without re­flecting on that process. How much longer can that work? Construction in the Anthropocene era will rely on the recovery and recycling of building ma­terials from the “urban ecosystem”, on ­separable building materials, life cycles, ­circular planning and cost control, and on responsible ownership instead of on linear, expansive growth categories such as demands, investment costs, landfill sites and the logic of the real estate market. Unthinking, unconsidered growth in consump­ tion offers no long-term solutions. Growth can­ not be an end in itself or an unquestioned basis for business. In fact, we are observing surprising growth in companies that consist­ ently and innovatively engage with a sustain­ ability agenda. A sustainable economy is not a ‘green’ fringe phenomenon but a current challenge for the mainstream in the energy business, in consumption and in the chem­ icals and building industries. Recent headlines on the explosion of construction costs, min­ imum pay, trends in rental prices and housing demand often obscure the real megatrend, which is sustainability. The old mantra of build­ ing “bigger, more, separate” is no longer an adequate response to the real issues that will impact cities in future. Recycling and state-of-the-art construction must become more part of our general knowl­ edge than they are now. Our school atlases were wrong when they described Germany as a country with few natural resources. Germany is in fact rich in raw materials, they are just not under the earth. Germany has never had more metal, more plastic, more oil-based composite ma­terials and more minerals. Yet despite this abundance of raw materials, we still import mineral and chemical raw materials from all over the world. We have everything, but think that we need more and more. This is because the raw materials we use are not or

not completely returned to the production pro­ cess at the end of the product’s life cycle. There are some exceptions, but recycling is only done on a relatively small scale. We still have a largely linear rather than a circular economy, which is ecologically disastrous, economically irresponsible, and socially unin­ telligent. Germans like to think of themselves as ‘recyc­ ling world champions’ but the country’s declared recycling rates measure only waste that is collected and brought to treatment ­facilities, not what comes out of those facil­­ ities. In fact, Germany recycles around 35 % of its waste collected for disposal, mainly easily recyclable, mass-produced materials such as glass, paper, PET and aluminium. This is not the case with high-tech materials that are an essential part of future strategies [2]. Com­pe­ti­ tive pressures, linear logistics and product design that is inimical to recycling still too often lead to decisions being made against recycling. Complacency, the absence of better ideas and lack of education on the issues do the rest. Yet there are growing streams of ma­terials in quantities that could be important in adding value, materials for which there is still no circular process, both in the construction business and in industry.

ness models and forms of cooperation offer a rewarding, solid and durable basis for the suc­ cess of this kind of economy [5] and represent a major reform programme for both society and the economy. Progress in this area and the solutions developed to achieve these goals will, however, challenge market mechanisms and politics. One new aspect of this economy will be that neither the market nor regulation alone will be able to promise success. The combined efforts of both commerce and policymakers will be needed to develop marketable solutions in a stable regulative environment. Urban mining in a form that can exploit its great transformative potential is still largely a futuris­ tic vision. Here, as in other areas of life, utopia must measure up to reality, must withstand an assessment of its impact based on real commitment, even if that may be painful and involve setbacks. However, a lofty lack of engagement will not achieve anything. Urban mining can hold its own because many t­echniques, processes, insights and expert approaches are already in place. It is develop­ ing quickly, although that does not mean it is developing quickly and extensively enough. Global urbanisation needs urban recycling to develop much faster. Reality also needs to measure up to the necessary utopia.

The Waste Management Act (Kreislaufwirt­ schaftsgesetz) needs to be fundamentally reformed. Lobbyists and protection of the usual vested interests have blocked this reform for too long. Multi-stakeholder partnerships among actors from civil society, the fields of practice and research, and companies offer better alternatives. They cannot make laws, but they can develop practical rules. Bestpractice standards can be drawn up in co­operative competition to help develop new practices and approaches. Digitalisation 4.0 forums [3] including sustainability codices [4] can have more impact through ­participation than might initially be expected. An ambitious circular economy can already function under today’s conditions and offers a range of opportunities for profit. New busi­ 7

Part A  Strategies and Potential

1  Circularity in Architecture – Urban Mining Design Urban Development Building Cubature Building Structure Building Technologies Joining and Materials Digital Data Costs

10 10 11 12 13 13 14 14

2 

Dismantling, Recovery and Disposal in Construction The Legal Background Waste Volumes and Recycling Quotas Dismantling and Demolition Methods The Cost and Effort Involved in Dismantling and Demolition The Development of the Anthropogenic Deposit Conclusion and Prospects

16 16 18 19 21 22 22

3 

An Overview of Rating Systems Recycling in Building Certification Recycling in Product Certification Conclusion and Prospects

24 24 28 32

4 

Using BIM to Optimise Materials Cycles in Construction Life Cycles Materials Cycle: Building – Construction Product An Example: Recycled Aggregate Made of Concrete and Sand-Lime Brick

32 32 32 33

5  An Elastic Standard – Urban Mining and Computational Design

34

6  Eco-Efficient Construction Using Local Resources Resources on the Building Site, the Genius Loci The “Vienna Model” 

36 36 37

“Metal elements”, company headquarters, Bad Laasphe (DE) 2010, m. schneider a. hillebrandt architektur

9

Circularity in Architecture – Urban Mining Design Annette Hillebrandt

All over the world, raw materials deposits are shifting. Many raw materials are now found not where they occur naturally, but in new, anthropogenic repositories. Large quantities of raw materials are stored in our building stocks. The paradigm shift that Urban Mining Design (UMD) represents is based on circular economy planning and costs that are analysed over a building’s entire life cycle and include its environmental impact (Fig. A 1.8, p. 15). Planners still too often think in terms of waste categories instead of materials cat­egories when they plan the end of structures’ usage and the recovery of post-use building material (see “Dismantling, Recovery and ­Disposal in Construction”, p. 16ff.). In future, buildings will be planned as a form of “interim storage” for raw materials, and the buildings as resources. Easily separable structures and building products are at the heart of a high-quality recycling process. Further essential prerequisites for recycling include an absence of hazardous materials and consistent responsibility for products. Clients and developers bear the responsibility for buildings, manufacturers for building materials and products, and planners and builders for building and ­dismantling. An Urban Mining Design strategy starts at the various ­levels of construction, ­furthers the sustainable use of resources, and reduces the consumption of primary resources by using secondary raw materials, conserving the soil, air and water that sustains us (Fig. A 1.1).

1. Size of repositories

Urban Development Conserving resources starts with reusing land and building stocks. Continued use and reuse should always take precedence over developing more greenfield sites and constructing new buildings. Condensing urban spaces

Making use of moderate, energy-efficient planned height development, urban development continues to rely on densifying spaces by adding more storeys to buildings, closing gap sites and building inside perimeter block developments or in the large spaces often left between blocks in post-war housing estates. This type of densification reduces both the destruction of land and the quan­ tities of resources required to build new infrastructure. Based on simulations of the local microclimate, it can help to counter climate change and its effects. When increasing the density of spaces, aspects such as providing or enhancing fresh air corridors, counteracting or avoiding “hotspots” by expanding areas that supply evaporative cooling, making surfaces more reflective, unsealing transport infrastructure surfaces, increasing areas of ground through which water can filter, decentralising wastewater treatment, and planting bushes and trees that will resist climate change and enhance bio­ diversity must all be considered.

Primary raw materials mining

Urban mining

˜

˜

2. Prospecting cost and effort 3. Amount of exploration

˜ ˜

4. Materials content

˜

5. Transport distance

˜

6. Demand orientation

˜

7. Processing cost and effort

˜

8. Environmental impact

˜

9. Social acceptance ˜  advantageous

˜ ˜  balanced

A 1.1

10

Circularity in Architecture – Urban Mining Design

A 1.2

A 1.3

Continuing and subsequent use of brownfield sites and existing buildings

Building Cubature

The option of regenerating existing buildings for reuse should be considered first. Continued use of a building’s support structure after it has been stripped back to its shell and its ­fittings have been dismantled is particularly important because most of a building’s mass is usually in its load-bearing structural elements. Older buildings’ inadequate technical perform­ ance and energy efficiency is one obstacle that frequently stands in the way of their continued use. Planning a “building within a building” can be a solution here, especially for large halls (Fig. A 1.2). Contamination is often used as an argument in favour of demolishing old buildings. In fact, contaminants always have to first be removed from a building and disposed of separately before demolition can begin, just as they would be before reuse. The cost of disposing of contaminants is ­therefore incurred in any case and cannot be a sole basis for deciding for or against demolition. If a building cannot be or can only partly be regenerated, reusing the building’s remaining materials must be a priority. Here there is potential for reuse in the form of the on-site recycling of materials from the building and soil mass as well as in intelligent terrain modelling. These measures can reduce waste volumes, conserve natural raw materials and diminish mobility emissions (see “Eco-Efficient Construction Using Local Resources”, p. 36ff. and Fig. A 1.3). In the case of soil contamination, especially on brownfield sites previously used for industrial purposes, it is worthwhile when planning large areas to check whether building laws allow for soil remediation underground in situ or whether soil remediation ex situ/on-site is possible. The best-case scenario here is to reuse the soil as arable land or disposal of it as a harmless substance in landfill. “Landfarming”, which involves using crushed demolition and soil materials in large-scale flat beds, can be a practical solution for outdoor areas.

Buildings’ sizes and forms and their underground construction volumes greatly influence our resources footprint. Building form

A compact building provides a good surface area-to-volume ratio. Energy can be saved by minimising the outer envelope and avoiding thermal bridges, which can occur around projecting structural elements. The quantities of materials required can be reduced by keeping joining details simple, which also reduces the cost and effort involved in repair and maintenance. When designing new buildings or enhancing the attractiveness of existing ones, buffer areas can extend residential space in transition seasons. Conservatories and single-glazed loggias and atria can form parts of high-quality residential spaces, even if they are unheated. They also shield users from noise and protect areas of the facade from weathering. Studies of the sun’s path can be carried out to optimise the positioning of buildings to maxi­ mise passive solar energy yields. Terrain

In keeping with the aim of leaving the natural world as “untouched” as possible, the construction of basement levels should be dispensed with for new buildings on greenfield sites. This protects soil organisms, which are an essential part of the ecosystem. It takes at least 100 years to form 1 cm of soil (Fig. A 1.4) [1]. Foundation designs that conserve soil are described in the chapters on “Detachable Connections and Constructions” (p. 42ff.) and in the “Detailed Catalogue” (p. 135ff.). New forms of consumer behaviour (such as the sharing economy) are making themselves felt in housing construction and challenging the need for basements, which are often just underused storage spaces, or for underground garages, when there are local connections to public transport and shared mobility services are available locally. Only high-value usable areas, such as sites on steep slopes, can justify the cost and effort involved in building subterranean spaces.

A 1.1 The benefits of urban mining for all three “pillars” of sustainability – a comparison of primary mater­ ials mining and urban mining (based on “Urban Mining – Ressourcenschonung im Anthropozän”, published by the Umweltbundesamt. 07/2017) A 1.2 A building-in-a-building concept used to retain large, uninsulated halls for an auditorium and ­laboratory building (“Hall 14a”), Wildau Technical University of Applied Sciences (DE) 2007, Ander­ halten Architekten A 1.3 Former industrial sites – continued use or recyc­ ling on-site! A 1.4 Untouched ground – footing detail. Experimental House Muuratsalo (FI) 1953, Alvar Aalto Sufficiency and rebound effects

Making do with enough, or sufficiency, is the most direct way to conserve resources and reduce waste, although our consumption of residential space seems to be moving in a ­different direction. In the year 2000, the average living space per person was just on 40 m2, in 2016 it was over 46 m2, an increase of around 16 %, [2] and the figure is forecast to grow to 51 m2 by 2050 [3]. Even the most flexible and efficient construction design and methods will be futile if the trend for each person to take up more living space continues. This rebound effect will elim­ inate all the improvements in efficiency in the area of resources conservation. At the programmatic planning level, sufficiency means minimising area per person while providing communal areas (shared spaces). This will require intelligent solutions involving multiuse spaces and the avoiding of temporary vacancies over the course of a day. At the policy level, measures that combat vacant commercial spaces, weak demand for housing (in economically underdeveloped areas) and empty luxury housing that is only used as an investment (in major cities) would all be desirable. A prescribed minimum number of users per m2 of plot area would be another helpful instrument in planning new buildings to achieve the required urban density.

A 1.4

11

A 1.5

Building Structure Flexibility of use is the most important precondition for future reuse, one that is largely determined by the building’s structure. Flexible floor plans and cross sections

Floor plans free of load-bearing walls allow users to divide up spaces in buildings in new ways at any time. Skeleton or frame construction offers the same performance as solid ­construction, but uses far fewer materials and provides greater potential for construction that conserves resources. A building envelope can be separated into different layers, depending on their function, such as protection from precipitation, wind proofing, thermal insulation and support structure. This can make it easier to optimise layers, making each one out of the material best suited for it. Skeleton construction offers an alternative to heavy, solid construction walls made of mineral building materials, whose recycling potential is limited. It does, however, involve greater demands in terms of joining techniques and planners’ knowledge of mate­r­ials (see “Detailed Catalogue”, p. 135ff., ­“Challenges in the Structural Design of Dis­ mantling- and Recycling-Friendly Constructions”, p. 118f.). Reducing load-bearing structural elements to columns and beams means that spaces in the horizontal plane can be freely defined and future spatial connections planned on the vertical plane. This can increase the ­variability of connecting spaces across mul­ tiple ­storeys (with the addition of extra stairs or galleries, for example), making it easy to change the space’s order and quality, e.g. by removing ceilings to create double storey heights. Converting a residential building for commercial use often involves retrofitting it with media ducts in suspended ceilings or hollow cavity floors (for ventilation, air conditioning and fire protection purposes). In contrast, an Urban Mining Design building is inherently designed to accommodate various kinds of future uses. Spatial heights in the building’s shell are designed to be multifunctional instead of being monofunctional and determined by minimum heights. 12

A 1.5 A resource-conserving frame has been built – now all it needs is flexible floor plan development. Building for users to plan themselves, project: Grundbau und Siedler, IBA, Hamburg (DE) 2013, BeL Sozietät für Architektur A 1.6 More in one: wall = shelf, wool felt-covered doors = pinboard and sound absorber, “Metallwerkstück” (metal workpiece), company headquarters, Bad Laasphe (DE) 2010, m. schneider a. hillebrandt architektur

If the development plan prescribes exact building heights, however, in the worst case it may be necessary to dispense with an entire storey. Here planners must review the legislation. If there are no historic structures adjoining the site and it is not listed for protection as an ensemble, construction laws should be flexible and allow for higher total heights to facilitate the creation of more forward-looking developments. The vertical shafts and ducts of a UMD building are adequately dimensioned to allow for technical retrofitting and positioned to expand the range of options for their subsequent use and enable various spatial configurations to be implemented. This is also true of the pos­ itioning of their access cores (stairs, lifts) and size (larger numbers of people will require broader emergency exit routes). Long-term use of buildings is essentially desirable because it is a direct way of conserving resources and reducing waste. Depending on the building’s location (e. g. in-demand innercity areas) it may be advisable to design the support structure to accommodate a range of usage options. Only sufficient reserves of load-bearing capacity will allow for the desired flexibility of use and enable the building to be adapted to future structural requirements. A building that is easy to inspect and repair will be a resilient building, and can respond robustly to demands made on it over the course of its usage that might otherwise result in renovation measures that can waste resources. ­Vertical ducts and cables that are surfacemounted or routed behind panelling can be serviced and repaired at any time without requiring costly and complex dismantling and demolition work (Fig. A 1.5). Flexible facades

A building’s reuse depends heavily on its facade’s flexibility. The facades of commercial and office buildings require different ­elements to those needed in residential buildings and have to meet different demands. Occupational health and safety requirements mean that office spaces need glare-free ­lighting at an even level, while residential ­buildings require areas of “introversion” (bath-

rooms and bedrooms) and “extroversion” (­balconies  /loggias). Demands on buildings’ thermal envelopes have grown sharply in recent decades and will continue to do so. Future building envelopes may have additional functions, for ­example as an energy generator, a green space to enhance biodiversity and cool the micro­climate, an information platform or ­display for data and news, or even as a space for receiving and storing goods and parcels. The evolutionary development of the facade will depend on structural components that are detachable and easily replaceable. The same is true of buildings’ interior fittings. Office and commercial space is now assumed to have a service life of 10 years [4]. Recyc­ lable materials and detachable structures can play a decisive role in their design and usage. Using the “fifth facade”

The roof, the building’s “fifth facade”, must be just as carefully and sustainably planned as the vertical facades. Their function extends beyond that of simple coverage and they are of great importance to the building and its ­surroundings. Green facades and roofs are ecological “compensation areas” and can be habitats for plants and animals that improve the surrounding climate by cooling and humidifying it. They can filter air pollution and particulates, improving the living and working environment and increasing a property’s value. Turning a flat roof into a green roof can offer a range of economic and ecological advantages. It protects the roof’s sealing from extreme temperatures and the effects of weather (storms, hail, UV radiation), extending the service life of the roof’s sealing compared with ordinary roofs. The evaporation that extensive green roofs ­provide can reduce annual precipitation run-off by more than half, while more intensive green roofs, those more like gardens, can offer water retention rates of up to 90 % [5]. A green roof also adds to the load that resists wind suction, allowing adhesion of the roofing membrane to be dispensed with. A further added value of the “fifth facade” lies in its potential for use as a space to set up photovoltaic systems.

Circularity in Architecture – Urban Mining Design

A 1.6

Building Technologies Building technology concepts and improved technical systems that are designed based on a holistic approach can help to conserve resources. Water management

Precipitation from roofs and areas of land should be allowed to percolate on-site in open depressions in the ground or in ­reservoirs. These can also be used to store water for watering gardens or as grey water ­reservoirs. Drinking water quality is currently only guaranteed by obtaining water from the public network. In Europe’s Mediterranean region, ­drinking water is a scarce commodity and a precious resource in the summer months, and has to be conserved. Cascading use of drinking water could help to alleviate this ­problem. Drinking water that has been used for cooking or personal hygiene (grey water) can be treated on-site after use and the treated water (purified grey water) reused to water the garden or as process water (in a dishwasher or washing machine or for toilet flushing), before it leaves the building as black water. This cascading use reduces the amount of drinking water that a residential building of ten units uses by up to 35 % [6].

good insulation for buildings is ­however still the foundation of a resource-­conserving energy strategy. Joining and Materials Easily dismantled structures and recyclable materials are crucial parameters for forwardlooking urban mining. Construction

Structures joined with detachable connections that can be quickly and cost-effectively dis­ assembled can be an alternative to the glued joints and composite joint structures that are currently widely used. They allow for the ­segregated recovery of materials without other substances adhering to them that is key in profitable recycling. Detachable connections also make it easier to carry out repairs and modernisation, making buildings more resilient and sustainable (see “Detachable Connections and Constructions”, p. 42ff.). Mono-material structures

Structural components made entirely of a ­single material make detachable connections unnecessary because all the components undergo the same recovery process (see ­“Mono-Material Construction”, p. 102ff.)

Energy management

Materials

The exclusive use of renewable energy is a ­fundamental prerequisite for reaching the EU’s ­climate goals. Energy can be best produced and stored decentrally in buildings (through photovoltaic elements in the building envelope, for example) or on-site (e.g. geothermal energy). Linking this kind of energy gener­ ation with forms of e-mobility (as a storage medium in a smart grid) is another option with great potential. Energy self-sufficiency obviates the considerable transformer losses incurred when energy is transported through the public grid and makes it possible to install a 12-volt network. The cascading use of water described above can also be used to generate energy. Minimising consumption by using appropriate devices such as LED lights and

The second prerequisite for Urban M ­ ining Design in construction is the recyclability of materials. It is currently very expensive to ­separate composites made of different groups of materials for recycling. The solid mineral construction materials and those of fossil- and petroleum-based origin ­currently in use make downcycling inevit­able. Even when such materials are recovered, ­products of the same quality standard can no longer be made from these materials using ­current technology. One-off use of these materials results in their irretrievable loss, so closedloop materials, i.e. those which can be used in practic­ally closed cycles, are a preferable choice. Urban Mining Design prefers to build using single materials free of additives or sur-

faces that are harmful to health, impede recycling, and reduce the building’s resale value. The chapter on “The Recycling Potential of Building Mater­ials” (S. 58ff.) deals with issues around choosing materials that will fit in with an urban mining approach in more detail. Urban Mining Design’s sufficiency approach dispenses with entire layers of building components in favour of exposed material surfaces. Materials remain raw and claddings and surface coatings are dispensed with. This approach prioritises users’ sensory experience of materials over an exclusively visual image and prefers authentic ageing to preservation, which can usually only be maintained by means of continuous renovation. A parallel strategy of using structural components for multiple purposes can also be pursued – e.g. doors that also serve as pinboards or sound absorbers (Fig. A 1.6). Reuse and continued use

Buildings with a modular structure have a ­better chance of subsequent reuse or the ­continued use of individual structural components. Often, reuse is the only option for really recyc­ling mineral building materials that do not have a high recycling potential (see “The ­Recycling Potential of Building Materials”, p. 58ff.). This kind of reuse is also easier when the components have large, repeating formats or modules of a uniform size. The market for reused materials has been severely limited to date because even before the design process begins, the funds for checking, purchasing and storing ­reused structural components must be spent. Using such materials also imposes restrictions on the design of the building’s appearance. Another impediment to reuse is the constant development of structural components. After just a few years, structural elements often no longer meet required standards and the manufacturers’ guarantees and approvals from building inspection authorities are often lacking for older materials. Reuse may currently have a niche existence in historic building conservation or ­private ­projects where profit is not the main ­priority, but it has broader future prospects due to the 13

A1.7

development of computational design. This technique uses data on the structure’s dimensions and structural capacity to generate ­optimised new computer-assisted applications and design forms (see “An Elastic Standard – Urban Mining and Computational Design”, p. 34f.). Products that can be returned to manufacturers, leasing and deposit systems

The high-quality recycling of complex composite building materials or multilayered building materials systems will only become reality when manufacturers accept responsibility for their products over their entire life cycles. Like car sharing and other new forms of ­mobility, the concept of “borrowing instead of owning” is also a promising model for the future of the construction industry. A few ­suppliers already practise a kind of product “hiring” or “leasing”. Depending on the ­product’s service life or obsolescence, these manufacturers ­provide users with a ­redesigned new product made of salvaged material at ­certain intervals. Manufacturers that take back their products free of charge after use or at the end of their use and provide the collection logistics required to do so are demonstrating this kind of comprehensive product responsibility (see “The Recycling Potential of Building Materials”, p. 58ff.). Evaluating recycling potential

The possibility of dismantling and recycling structures is included as a parameter, although a fairly vaguely formulated one so far, in buildings’ sustainability ratings (see “An Overview of ­Rating Systems”, p. 24ff.). New quantitative and practicable benchmarks will, however, be required for the formulation of a clear policy framework for recycling. The goal of conserving resources (and reducing waste) in construction will only be achieved if it is both economically feasible and socially acceptable. All three “pillars” of sustainability, i.e. the economic, ecological and social aspects, must be taken into account in any quantitative assessment of a building’s recycling potential (see “Can Loop Potential Be Measured?”, p. 108ff.). 14

Digital Data In a 2017 publication, the German Environment Agency (Umweltbundesamt – UBA) called for an assessment of a building’s ecological performance over its entire life cycle by means of an electronic “materials passport” [7]. All materials, in the exact quantity and composition used, can in future be mapped in a virtual “twin” of each building. Building Information Modelling (BIM) can be used to calculate the amount, quality and ­seasonal availability of recycled materials found regionally (see “Using BIM to Optimise Materials Cycles in Construction”, p. 32f.).

A 1.7 Vehicle production as a role model – the product is easy to dismantle and repair A 1.8 Closing loops in a circular economy – the ­expanded Urban Mining Design strategy, from www.urban-mining-design.de/index.php?id= ­urban-mining-bauvorhaben

(p. 120ff.) includes an experimental comparison of the production, maintenance and endof-life costs of conventional as well as of constructions based on dismantling and ­recycling. In the foreseeable future the end of a building’s service life will be included in the calculations of its overall cost. Buildings designed in accordance with urban mining principles to be optimised and planned repositories of raw materials will increase in value, wherever they are.

This new planning phase, i.e. dismantling planning, will be essential in the paradigm shift towards a circular economy. It will open up new fields of work for planners and with them the necessity to take the substantial add­ itional planning effort involved into account in legislation regulating pay for architects and engineers. Costs In future, the cost of constructing, maintaining, ­dismantling and disposing of buildings will be subject to increases and shifts and the cost of disposing of non-recyclable materials will probably increase exponentially. Urban Mining Design takes into account not only a building’s production cost at the outset, which has been standard practice to date, but also the costs accruing over its entire life cycle through to the end of its usage and beyond, when either costs for disposal are incurred or a profit from subsequent reuse and/or recycling is made. The brief service life of cheap materials makes short renewal cycles necessary and often results in higher maintenance costs due to ­frequent replacements. Materials contaminated with dangerous substances are often extremely expensive to dispose of. In contrast, closedloop materials increase in value and yield a profit after they are dismantled. The chapter on “Cost Comparisons of Conventional and Urban Mining Design Constructions”

Notes: [1] Schutzgemeinschaft Deutscher Wald (SDW): Waldböden. http://www.sdw.de/waldwissen/waldboden/ entstehung-und-aufbau/index.html. Retrieved on 28.10.2017 [2] Fortschreibung des Wohngebäude- und Wohnungsbestandes – Lange Reihen 1969 bis 2016. Published by the Statistisches Bundesamt, 2017, www.destatis. de/DE/Publikationen/Thematisch/Bauen/Wohn­ situation/FortschreibungWohnungsbestand.html. ­Retrieved on 06.10.2017 [3] Deilmann, Clemens et al.: Materialströme im Hochbau. Zukunft Bauen – Forschung für die Praxis, Bd. 6. ­Published by the Bundesinstitut für Bau-, Stadt- und Raumfor-schung. Berlin 2017, p. 56. www.bbsr.bund. de/BBSR/DE/Veroeffentlichungen/ZukunftBauenFP/ ZukunftBauenFP_node.html. Retrieved on 25.05.2018 [4]  cf. DGBN System version 2017 [5] Städtebaulicher Rahmenplan Klimaanpassung, Anpassungskomplex “Hitze”. Published by the City of Karlsruhe, Stadtplanungsamt, tab. 4, www.karlsruhe. de/b3/bauen/projekte/klimaanpassung. Retrieved on 25.05.2018 [6] Hartmann, Frank: Wasserwirtschaft in Wohngebäuden. In: db deutsche bauzeitung 11/2016, p. 66 –70 [7] Urban Mining – Ressourcenschonung im Anthropo­ zän. Published by the Umweltbundesamt, 07/2017, tab. 1. www.umweltbundesamt.de/publikationen/­ urban-mining-ressourcenschonung-im-anthropozaen. Retrieved on 25.05.2018

Circularity in Architecture – Urban Mining Design

A5 Computational Design

Reuse and further use of building component

A2 + A3 Rating systems

Qualitative Optimised loop potential +

B4 + B5 Quantitative

A4 Facility management BIM building material passport Optimised dismantling design

Heat recovery Water

Computational sphere

Electricity A1 Building technology Heat

Minimisation

A1 Cubature and shell

B7 EoL

Optimisation

A1 Structural flexibility

Ease of repairs

Operation

Use

On-site + Off-site

A1 Noncontaminated

Contaminated ∫ Demolition ∫ Landfill class III

A1 Soil decontamination

Noncontaminated

Optimisation

Cooling through evaporation from open water Surface albedo

Newly constructed building, including outdoor facilities

Sale

B2 + B7 Choice of material

Architectural Cycles Urban Mining Design Subsequent use of building

Input minimisation Output minimisation

With recycled component – waste avoidance

Sale Subsequent use of land

100 % recycled material + Large recycled component

Recycling: closedloop material + Downcycling, higher quality within construction Downcycling, lower quality outside of construction

Reuse and further use of building component +

B3 Mono-material construction

Pure material recovery +

Easy to dismantle, easy to repair

Pure material recovery + Reuse and further use of building component +

Difficult to dismantle Continue here

A1 Microclimate optimisation Building arrangement

Not certified Renewable as sustainable resources + Certified as sustainable + Nonrenewable = = resources

B2 Modularity, format

B1 Type of construction

Continue here

Continue here

By-product, recovered pre-use material With loop potential recyclingfriendly

Materialisation

Continue here

Soil-conserving

Passive / active solar gains

Recycling potential

Green spaces

Fresh air corridors, Air circulation

Green roofs and facades

Facade

Continue here

Sale

Greening with biodiversity-promoting plant selection

Shading passive solar gains

Vertical

Without loop or subsequent use potential

Contaminated ∫ Demolition ∫ Landfill class III

Unsealing seepage

Horizontal

Without recycled component

Recycling or downcycling of material

A6 Recycling or On-site + downcycling of material Off-site

Energetically optimised

Life cycle assessment

Building repurposing and refurbishment

Off-site

Functionally sufficient

Supporting structure

Pure manufacturing cost

Reuse or further use of building component

Radio control

Infrastructure Cost analysis

Ease of maintenance

On-site +

Surface heating / low-temperature

Minimised disposal costs

B7 Upkeep

Off-site

Generation and storage: decentralised and renewable

Taking into account

Profits from recycling or downcycling +

On-site +

12-volt network

Microclimate-optimised

Profits from reuse or further use +

Longevity ∫ reduced replacement frequency

Generation and storage: decentralised and renewable

Building controls

Minimisation

Absence of hazardous materials Minimised waste volume

Utilisation cascade

A1 New building location

Urban area

Developed land, new construction Developed land, densification + New development

New building densification Height increases / extensions Closing gaps between buildings

Outdoor facilities

Continue here Rural area

Building shell A 1.8

15

Dismantling, Recovery and Disposal in Construction Anja Rosen

Real circular value creation in construction is the shared goal of actors in the fields of politics, ­science and commerce. It is often reported that a circular economy is already standard practice in the construction sector, although sweeping state­ ments are often made and terminology is used imprecisely. Despite existing legal regulations enabling and encouraging it, recycling is not yet being carried out to a high standard of quality. This chapter provides information on the current legal framework and recycling quotas and ex­ plains the links between the legal situation, re­ cycling practice and dismantling processes in use. The Legal Background The ProgRess II resource efficiency programme initiated by Germany’s federal government in 2016 set the goal of increasing Germany’s ­overall raw materials productivity by 30 % by 2030 compared with 2010. The German gov­ ernment was called upon to take a series of measures, including facilitating a circular economy based on statutory regulations and extending the scope of the application of the EU Ecodesign Directive and product responsi­ bility as instruments for reducing waste [1]. The Construction Products Regulation

The EU Construction Products Regulation of March 2011 sets out fundamental requirements for buildings and the main features of construc­ tion products. It states that a building must “be designed, built and demolished so that natural resources are used sustainably”, “the building, its materials and components (must) be able to be reused or recycled after demolition” and “in building, environmentally friendly raw mater­ ials and secondary construction materials must be used” [2]. The Construction Products Regu­ lation does not currently stipulate any particular quality or quantity of recycling. A 2.1 Levels of waste legislation relevant to dismantling and recycling in construction A 2.2 Classification of construction and demolition wastes based on the List of Wastes (representa­ tive excerpt) A 2.3 Waste hierarchy in the Waste Framework Directive

16

Laws on waste

The law on waste in Germany is regulated at various levels by a range of laws, guidelines and ordinances. Figure A 2.1 shows the most relevant of these for the construction sector.

The EU Waste Framework Directive and German Waste Management Act The European Waste Framework Directive defines important terms, distinguishing for example between waste and by-products and the “end of waste”, and overrides national law in all EU member states [3]. The end of waste is reached at the point at which waste has been recycled to make a product for which there is demand and a purpose. The EU Commission can pass specific regulations for certain waste streams. End-of-waste criteria for mineral con­ struction and demolition waste are set out in a new substitute building materials ordinance [4]. It stipulates that only class 1 recycled construc­ tion materials can be made into products and imposes strict requirements on the absence of pollutants (see “Statutory restrictions”, p. 17f.). The Waste Framework Directive also pre­ scribes a five-tier waste treatment hierarchy (Fig. A 2.3). In Germany the EU directive is implemented at national level in the German Waste Management Act (Kreislaufwirtschafts­ gesetz – KrWG) [5]. The Waste Catalogue Ordinance The Waste Catalogue Ordinance classifies waste according to its origin and hazardous­ ness [6]. For each type of waste a six-digit code in the List of Waste forms the basis for the waste’s recovery or disposal, based on which annual waste statistics are also issued (see “A statistical overview”, p. 19f.). An asterisk at the end indicates a hazardous waste code (Fig. A 2.2). The German Commercial Waste Ordinance Among the most important regulations govern­ ing the circular economy in the construction sector are the Waste Wood Ordinance (see “Recycling and Reusing Wood as Material – Waste and Recovered Wood”, p. 65) and the Commercial Waste Ordinance. The Commer­ cial Waste Ordinance was amended in April 2017 [7] to adapt it to the EU’s waste hierar­ chy. Since August 2017, construction and ­demolition waste must be separated into the following groups and mainly processed for reuse or recycled in accordance with the Ger­ man Waste Management Act:

Dismantling, Recovery and Disposal in Construction

Waste Framework Directive

European level

Cycle Management Act Waste Catalogue Ordinance Landfill Ordinance Draft: Substitute Building Materials Ordinance (Ersatzbaustoffverordung)

German national level

Waste Wood Ordinance Bio-waste Ordinance Commercial Waste Ordinance Federal State waste laws LAGA M 20 – Rules of the Federal States’ Working Group on Waste Issues (Länderarbeitsgemeinschaft Abfall)

Federal State level

Waste regulations of individual cities and districts

Municipal level A 2.1

• Glass • Plastics •  Metals, including alloys • Wood •  Insulating materials •  Bitumen mixtures •  Plaster-based construction materials • Concrete • Brick •  Tiles and ceramics The Ordinance also sets out documentation obligations and exemptions, e.g. due to a lack of technical options or economic unrea­ sonableness.

Code

Description of waste in the Waste Catalogue

17

Construction and demolition waste (incl. excavated materials from contaminated sites)

17 01

Concrete, brick, tiles and ceramics

17 01 01

Concrete

17 01 02

Brick

17 01 03

Tiles and ceramics

17 01 06 *

Mixed or separated concrete, brick, tiles and ceramics that contain hazardous materials

17 01 07

Mixtures of concrete, brick, tiles and ceramics, with the exception of those falling under 17 01 06

17 02

Wood, glass and plastics

17 02 01

Wood

...

Statutory restrictions Measures to achieve a recycling quota of 70 per cent by weight of non-hazardous con­ struction and demolition waste by 2020 are legally prescribed at European and national levels, although without any further require­ ments regarding quality. As long as these goals are fairly vaguely formulated, manufacturers will only fulfil the responsibility for their products that Section 23 of the German Waste Manage­ ment Act imposes on them at low levels. Prioritising the use of recycled and recyclable products in public works projects could offer impetus for the establishing of a circular econ­ omy. Although Section 45 of the German Waste Management Act stipulates that the relevant authorities are obliged to review this possibility, they have not done so in practice to date, in part due to legal uncertainties. On the one hand, public works contracting regulations ­stipulate that tenders must be product-neutral, while on the other hand Germany’s federal ­government and Länder (state) governments worked on the overarching general ordinance for more than ten years until it was passed in May 2017. This ordinance and the introduction of the Substitute Building Materials Ordinance (Ersatzbaustoffverordnung), the amendment of the Federal Soil Protection and Contaminated Sites Ordinance, and the revision of the Landfill Ordinance and Commercial Waste Ordinance are designed to harmonise the more stringent requirements that establishing a circular ­economy place on the protection of soil and

17 03

Bituminous mixtures, coal tar and products containing tar

17 04

Metals (including alloys)

17 05

Soil (including excavated materials form contaminated sites), stone and excavated materials

17 06

Insulating materials and construction materials containing asbestos

17 08

Plaster-based construction materials

17 09

Other construction and demolition waste

* hazardous wastes

A 2.2

Avoidance Measures to reduce the amount of waste, harmful effects on the environment and health or contaminated content has priority over Reuse of products or components for the same purpose as the original use has priority over Recycling Processing of waste into products, materials or substances for the original purpose or other purposes has priority over Other Recovery Especially for use in energy generation and backfilling has priority over Disposal A process that does not involve recovery, even though materials or energy may be recovered as a side effect A 2.3

17

Abfallaufkommen gesamt in Deutschland 2014 in Mio t

Bau- und Abbruchabfälle

50.6

Siedlungsabfälle

59.5 401 million tonnes

Abfälle aus Gewinnung und Behandlung von ‡ Construction and demolition waste Bodenschätzen ‡  Residential waste ‡ Waste from extracting and treating natural Übrige Abfälle (insbesondere resources aus Produktion und Gewerbe) ‡ Other waste (especially from manufacturing and industry) Abfälle aus Abfallbehandlungsanlagen ‡  Waste from waste treatment plants

209.5

30.2 51.1

Bau- und Abbruchabfälle in Deutschland 2014 in Mio t. 0.7

0.1 0.3 3.1

Boden, Steine und Soil,Baggergut stone and dredged materials ‡  Concrete, tiles and ceramics ‡ Fliesen Beton, Ziegel, undbrick, Keramik ‡ Wood 1) 1 Holz ‡ Glass 1) ‡ Plastic 1) Glas 1 1 ‡ Glass, plastics and wood, as hazardous Kunststoff waste 1) Glas, Kunststoff und Holz, als gefährliche Abfälle ‡ Bituminous mixtures, coal tar and 1products containing tar Bitumengemische, Kohlenteer und teerhaltige Produkte ‡  Metals, including alloys and cables 1) Metalle, einschließlich Legierungen und construction Kabel 1 ‡ Insulating materials and

3.9

0.7 0.7

7.3 16.5

209.5 million tonnes 55.3

A 2.4

121.1

1 ­materials containing asbestos Dämmmaterial und asbesthaltige Baustoffe ‡  Plaster-based construction materials 1) 1 Baustoffe auf‡  Gipsbasis Other construction and demolition waste,  1) ­includinggemischte mixed waste Sonstige, einschließlich Bauu. Abbruchabfälle 1

 1)

1

1)  ohne Verbringung ins Ausland, da nicht statistisch erfasst not including transport abroad because that

is not recorded in the statistics

A 2.5 Verbleib der ungefährlichen Bau- und Abbruchabfälle in Deutschland 2014 [Mio. t]     [mill. t] Boden Steine 12.1 12.1 0.1 % Recycling Recycling incl. ‡ Soil andund stone 1.7% 0.2 % inkl. Downcycling Straßenaufbruch downcycling ‡  Road construction waste 12.8 12.8 0.1 % 33.5 % Bauschutt 42.5 42.5 33.5 % rubble ‡  Building 0.1 % ‡  Building site waste   Baustellenabfälle 0.2 0.2 6.0 % ‡ Plaster-based 8.4 % Bauabfälle aufconstruction Gipsbasis 0.0 6.3 % waste   0.0 89.5 89.5 7.0 % Boden Steine Sonstige Other recovery ‡  Soil andund stone 0.5 0.5 Verwertung Straßenaufbruch 56.0 % ‡  Road construction waste   4.3 % 56.0 % 0.2 % 8.7 Bauschutt ‡ Building rubble  8.7 21.0 % 14.2 14.2 ‡  Building site waste Baustellenabfälle 202 million tonnes ‡ Plaster-based Bauabfälle aufconstruction Gipsbasis 0.2 waste   0.2 16.9 16.9 Boden Steine Beseitigung Disposal andund stone ‡  Soil % 0.3 0.3 Straßenaufbruch 0.1 % 10.5 10.5 % ‡  Road construction waste   44.3 % 3.4 Bauschutt ‡ Building rubble  3.4 ‡  Building site waste   Baustellenabfälle 0.2 0.2 ‡ Plaster-based Bauabfälle aufconstruction Gipsbasis 0.4 waste   0.4 RC-Baustoffverwendung in Deutschland 2010 in Mio. Tonnen A 2.6

0.8 % 6.9 % Straßenbau 16.1 %

Erdbau

53.8 %

Gesteinskörnung für Beton

In Germany, general construction law, Federal State construction laws (building regulations) and the Construction Contract Procedures rules (Vergabe und Vertragsordnung für Bauleistun­ gen – VOB) regulate the construction as well as the dismantling of buildings. A range of other standards and guidelines apply to the dismant­ ling and demolition of buildings, including: •  DIN 18 007 Demolition works [10] • ATV DIN 18 459 Demolition and dismantling works [11] and • VDI Standard 6210 Blatt 1 Demolition of civil constructions and technical facilities. The legal requirements regarding dismantling in these standards refer to the laws on waste described on page 16 in dealing with the ­separation of demolition materials for reuse. As long as they do not place more stringent requirements on recycling quality, however, demolition will only meet the high demands of selective dismantling (see p. 20) in a few ­isolated cases. Waste Volumes and Recycling Quotas

‡  Road construction sonstige Zwecke ‡ Earthworks

‡ Asphalt ‡  Aggregates for concrete ‡  Other purposes A 2.7

18

Laws and standards on dismantling

Asphalt

65.2 million tonnes

22.4 %

groundwater [8]. The Substitute Building Mater­ ials Ordinance is being drafted to consistently regulate the requirements made on the produc­ tion and use of substitute mineral construction materials in technical structures across Ger­ many and increase the acceptance of recycled materials through legally binding quality moni­ toring. The Ordinance does not, however, cover the use of recycled construction materi­ als in building construction. Requirements regarding the recovery and recycling of mineral waste have to date been formulated in Memo­ randum 20 issued by the Federal States’ Work­ ing Group on Waste Issues (Länderarbeitsge­ meinschaft Abfall – LAGA M 20) [9], here too, with a focus on recovery and recycling in con­ struction (Fig. A 2.9).

Germany is generally regarded as recycling world champion, but closer inspection shows that this impression is misleading, including in the construction industry.

Dismantling, Recovery and Disposal in Construction

Production of natural aggregates

Concrete production Cement production

Production of recycled aggregates Concrete C30/37

Gravel extraction

RC concrete C30/37 (25 % concrete granulate) Concrete C30/37

Land use

RC concrete C30/37 (25 % concrete granulate) Concrete C30/37

Greenhouse effect

RC concrete C30/37 (25 % concrete granulate) Concrete C30/37

Energy resources

RC concrete C30/37 (25 % concrete granulate) 0% A statistical overview

Around 52 % of all waste in Germany comes from the construction sector. In 2014, total waste volume from the sector was 401 million tonnes, 210 million tonnes of it construction and demolition waste (Fig. A 2.4). In purely ­statistical terms, Germany fulfils the recycling quota of 70 % that the legislation calls for (see “Statutory restrictions”, p. 17f.). 89.5 % of the 202 million tonnes of non-hazardous ­construction and demolition waste gener­ ated in 2014 was recycled (Fig. A 2.6) [12]. According to the relevant statute, however, this quota also includes to a lesser extent the recovery of other materials, in particular the backfilling of building rubble and soil waste in mine pits. Only recycling for the pur­ pose of energy generation is not included in the quota. Most of this waste is in the form of heavy min­ eral construction materials. The “Kreislaufwirt­ schaft Bau” initiative has published statistics on mineral construction waste every two years since 2006. In 2014, the recycling quota for building rubble, which by far makes up the largest proportion of demolition waste from building construction (not including soil and stone), was 77.8 % [13]. This is, however, not really recycling but so-called “downcycling”, i.e. the recovery of materials with a range of uses more limited than the original material. Building rubble is crushed, turned into recy­ cling aggregate and used mainly in road ­building (Fig. A 2.7). Yet even the very small proportion of highgrade concrete reused in concrete produc­ tion does not represent a closed materials

A 2.4  Total waste volume in Germany in 2014 in mill. t A 2.5 Construction and demolition waste in Germany in 2014 in mill. t A 2.6 Disposition of non-hazardous construction and demolition waste in Germany in 2014 in mill. t A 2.7 Use of recycled building materials in Germany in 2010 in mill. t A 2.8 Impact assessment for structural concretes, recyc­led concrete with an increased cement ­content, ratio in % A 2.9 Installation classes based on LAGA M 20 ­(Länderarbeitsgemeinschaft Abfall)

25 %

cycle, because new concrete cannot be made from crushed concrete without the ­addition of more cement (see “Concrete”, p. 70). Cement production is, however, the main problem because it contributes signifi­ cantly to concrete’s environmental impact. Swiss studies on the ecological life cycle of concrete show that using recycled aggregates can save ­abiotic raw materials (gravel, sand), but can increase energy consumption and greenhouse gas emissions if, due to a greater void content, more cement is used to make the concrete (because of the use of crushed grit) (Fig. A 2.8) [14]. Kreislaufwirtschaft Bau’s monitoring of “build­ ing site waste” covers construction and demo­ lition waste comprising wood, glass, plastics, metals, insulating materials and mixed con­ struction waste. Recycling of these materials

Origin of waste

50%

75 %

100 %

A 2.8

is not yet recorded in the official statistics, so the recycling quotas were researched for this book based on other sources (see “The Recycling Potential of Building Materials”, p. 58ff.). Dismantling and Demolition Methods Dismantling and demolition play a key role in enabling materials recovery because the more selectively dismantling or demolition is carried out, the more accurately and cleanly the materials can be recovered and the eas­ ier it is to meet the quality demands made on recyclates. The methods and techniques used play a major role in this process. The ­following demolition methods are commonly used [15].

Composition of waste

Site conditions Installation

Type of installation

Installation classes

Z0

Z1

Z2

Z3

Recovery

Installation class 0

Unrestricted installation

Z4

Z5

Depositing in landfill / disposal

Installation class 1

Installation class 2

Restricted open ­installation (water-­ permeable)

Restricted i­ nstallation with defined technical ­safety ­measures (not waterpermeable)

Above-ground landfill DK 0 for inert waste

DK I

DK II

Above-ground landfill for ­wastes that comply with the classification criteria based on Appendix 3 No. 2 of the DepV

DK III

DK IV

Above-ground landfill for non-haz­ ardous and hazardous waste that complies with classification criteria based on Appendix 3 No. 2 DepV

Underground landfill for ­hazardous waste

A 2.9

19

A 2.10 Extent

Requirements and applications will vary depending on whether a building is to be com­ pletely or only partly demolished or dismantled. Partial and complete demolition Partial demolition is when sections, fittings and installations or parts of buildings are removed but the structural stability of the remaining parts of the building is retained. Complete disposal of a structure is referred to as complete or total demolition. Gutting Gutting is the dismantling of a building back to its shell. Structural components that do not influence its structural stability are removed (e.g. light partition walls, windows, doors and technical equipment). Gutting is carried out either before demolition or can also pre­ cede comprehensive renovation in which the support structure is retained and remains in use. After separation

Separating reusable materials on­site is the first step in recycling. In the order of effort involved from low to high, the following processes can be distinguished. Conventional demolition Conventional demolition is the coarsest way of disposing of buildings. The building is torn

a

20

b

down without first being gutted or having its waste separated, so its materials are inevit­ ably mixed. They are then either separated subsequently (manually or by machine) or the demolition waste is completely disposed of as mixed construction waste. The high costs of disposal that this entails mean that conventional demolition is now used only for small structures built with only a few different materials. Selective demolition According to the German Demolition Asso­ ciation (Deutscher Abbruchverband – DA), selective demolition is currently the most com­ mon process for the complete demolition of buildings [16]. Materials to be salvaged are selected before, during or after demolition (Fig. A 2.10). Selective dismantling Selective dismantling involves dismantling or removing different carefully sorted and separated materials before the support structure is demolished (Fig. A 2.11). This process offers the best prerequisites for the optimum recycling of demolition waste after disassembly. Disassembly for scrap and recovery This method is used mainly for steel structures, which are dismantled or disassembled and then broken down for scrap.

c

d

Disassembly for reuse Disassembly for reuse is practised mainly with historic structural components and materials and unrivalled in terms of resource conservation, because all the raw materials used to produce the structure, including the energy, are retained. Structural components are carefully disassembled in reverse order to that in which they were installed so that they are not damaged and can be reused else­ where. Methods and technologies

Until the middle of the previous century, dis­ mantling – like building construction – was done mainly by hand, using relatively simple mechanical tools. The purpose of dismantling was usually the reuse or recycling of materials. Now, in contrast, demolition is a high­tech, energy­intensive process and buildings are primarily removed so that their sites can be reused. Manual methods Today, manual methods are mainly used for gutting buildings. Personnel­intensive demoli­ tion by hand is usually limited to an accom­ panying procedure in areas in which structural elements must be removed without too much vibration or where machines cannot be used, e.g. due to the load­bearing capacities of slabs. For the purposes of recycling, materials can best be selected using manual methods.

e

f

A 2.11

Dismantling, Recovery and Disposal in Construction

Developers and clients are not usually particu­ larly interested in what happens to demolition waste. As original owners and producers of such waste they are responsible only for its proper disposal, but not for the quality of recov­ ery or recycling, so the choice of demolition method is usually left to the demolition con­ tractor, unless activities that require special permits such as blasting and explosions are involved. DIN 18 007 notes, however, that it may be necessary to prescribe a method in some cases because of environmental and economic aspects and the need to allow for various subsequent works. In practice, the methods used will depend on objective conditions such as the structure to be demolished (its structure, construction method, materials, height, etc.) and building site condi­ tions (adjoining buildings, media connections, etc.) and in particular on economic aspects.

‡

‡

‡

Pushing in

‡

‡

‡

Pulling in

‡

‡

‡

‡

‡

Press cutting

‡

‡

Shear cutting

‡

‡

Disassembly

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

 for all structural components

‡

High-alloy steel and cast iron

Nonferrous metals

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡

‡ ‡

‡

Steel

Reinforced concrete

Unreinforced concrete

Foundations / foundation elements

Walls

Columns

Beams / girders

‡

‡

‡

‡

‡

‡

‡

‡

‡

Chiselling

Explosion

Roofs

Tower-like structures

‡

Plastics

Hammering

‡

Masonry

‡

Construction material

Wood

Tapping out

Structural component

Ceilings / floors

Multistorey wall structures

Process

Structure

Insulating and fittings materials

The cost and effort involved in dismantling and demolition

Suitability of demolition method for selective dismantling of buildings

Multistorey frame structures

Demolition technology has continuously changed in the past 30 years with the increasing complexity of demolition and to adapt to greater requirements due to the increasing building heights, volumes and speed required. The ­technology of demolition equipment works very efficiently, but it is also among the most invest­ ment- and energy-intensive in the construction sector. Hydraulic excavators with ­various addon components such as canti­lever arms and quick-change systems are commonly used (Fig. A. A 2.10). Demolition robots, remote-­ controlled demolition machines that offer the advantage of greater workplace safety and run on electricity and are therefore emission-free, are increasingly being used inside buildings. DIN 18 007 defines and explains the various methods. Following the approach taken in Appendix A of this standard, Fig. A 2.12 ­compares their suitability for selective dis­ mantling depending on the structure, structural components and materials. The methods described can be used either individually or combined [17].

Low-rise buildings and halls

Machine methods

‡

‡

‡

‡

‡

‡

‡

‡

‡

Drilling Element of another process / preparatory measures Sawing Cutting Grinding

Depending on the structure

‡

‡

‡

‡

‡

‡

Cutting, thermal ‡ especially suitable  

suitable   ‡  suitable after gutting

A 2.10  Selective demolition using demolition grapples A 2.11 Selective dismantling, showing the example of a floor a Removal of floor’s upper layer b, c Cutting into screed

A 2.12

d Removal of screed e Removal of impact sound insulation f Disposal, materials carefully separated A 2.12 Suitability of demolition methods with a focus on selective dismantling based on DIN 18 007

21

Demolition and dismantling costs [€]

65,000

Disposal costs high Personnel costs high

60,000

Disposal costs low Personnel costs high

55,000

50,000 Disposal costs high Personnel costs low

45,000

Disposal costs low Personnel costs low

40,000 Conventional demolition

Selective demolition

Dismantling / Disassembly A 2.13

Here, cost-effectiveness depends on: • Dismantling  /disassembly costs - Workers required (their number and qualifi­ cations) - Use of equipment /machines (type and quantity, operating materials) -  Material (safety measures and equipment) •  Disposal costs When the costs of dismantling in proportion to disposal costs are examined and divided into conventional demolition and selective ­dismantling, it becomes clear that personnel costs are more relevant to the overall costs than the costs of disposal (Fig. A 2.13) [18]. This explains why selective dismantling, which enables recycling but requires an ex­­ tensive deployment of workers, is not used ­universally. The costs of dismantling and demolition are usually calculated based on the contractor’s experience. In contrast to cost estimates for building construction there is no general, pub­ licly available data (e.g. such as the German Construction Price Index). Estimating costs is subject to fairly great uncertainty because many parameters cannot be identified or can only be identified with great difficulty in advance (e.g. structural components covered with cladding). A lack of information on the materials involved often results in very rough estimates of dismantling and disposal costs based on the structure’s gross volume and /or on the average calculated time required for the floor area involved. The chapter on “Cost Comparisons of Conven­ tional and Urban Mining Design Constructions” (p. 120ff.) shows the end-of-life costs for selected structures. The Development of the Anthropogenic ­Deposit Building stocks in Germany have grown con­ tinuously since the Second World War and now form an enormous, man-made, anthropogenic repository of raw materials with an estimated volume of 15 billion tonnes (Fig. A 2.14). To cal­ culate the recycling potential available in the 22

total building stock, scientists have made ­forecasts and carried out sensitivity studies for mass flows in 2030 and 2050 based on ­construction and demolition activities in 2010. According to the mass flow model, the input streams for new building and renovations in 2010, at 121 million tonnes, were three times as large as the output streams from disman­ tling. Based on forecast population growth, this trend will probably reverse from 2030 and by 2050 materials volumes from ­dismantling could exceed those from new building and ­renovations 1.5-fold, if the increase in vacant buildings is to remain ­moderate (Fig. A 2.15). One of the study’s main messages was that the use of recyclates, in products in building construction, based on optimistic assumptions of improved conditions for a circular economy and taking theoretical technical upper limits into account, could grow from an average of approximately 7 % currently to 21 % in 2050 [19].

A 2.13 Impact of disposal costs and personnel costs on demolition and dismantling costs based on four model calculations for a solid residential building (built in 1856) with 4,200 m3 of gross volume A 2.14 Material deposited in building stocks in Germany in 2010 in million tonnes by material group A 2.15  Forecast of materials streams in construction A 2.16 Reliability of disposal based on landfill capacity in Germany

As long as the real recycling of concrete and other mineral construction materials remains impracticable, the only the way of conserving these materials, which use up lots of resources and result in large quantities of emissions, is to work with the sustainability principles of effi­ ciency and sufficiency. The examples of build­ ings in the “Detailed Catalogue” (p. 135ff.) therefore focus on construction methods that already ensure recyclability at a high-quality standard. For economic reasons, current demolition tech­ niques are primarily designed to ensure speed and to require as few workers as possible. The stricter rules governing materials separation in the amended German Commercial Waste Ordinance (GewAbfV) and the tendency of dis­ posal costs to rise will mean that selective ­dismantling will become more established. For current new building projects, this means that easy separation of materials by means of detachable connection techniques is the best way forward (see “Detachable Connections and Constructions”, p. 42ff.).

Conclusion and Prospects Currently, the construction sector can only meet the recycling quotas called for in legisla­ tion at a low-quality standard and is far from a real circular economy with closed materials cycles. Since resources are increasingly in short supply, demolition activity is increasing, landfill capacity is shrinking (see “Limited ­landfill capacity”, p. 124 and Fig. A 2.16) and demands on secondary raw materials in build­ ing construction are growing, there is an urgent need to generate closed materials cycles in building construction. This will be a major chal­ lenge for mineral construction materials pro­ ducers. Researchers are, however, already ­providing some solutions. Concrete, for ex­ample, may soon be able to be fragmented into aggregate and hardened cement by means of electrodynamic fragmentation. Ultrashort high-voltage impulses (flashes) under water create a pressure wave in the concrete that reduces it to all its individual components [20]. The question of how reactive cement can be extracted from hardened cement is, how­ ever, currently unresolved.

Notes: [1] Recommended resolution and report of the Commit­ tee for the Environment, Nature Conservation Building and ­Nuclear Safety (Ausschuss für Umwelt, Natur­ schutz, Bau und Reaktorsicherheit - 16. Ausschuss), Drucksache 18/9094, 06.07.2016 [2] Regulation (EU) No. 305/2011 of the European Parlia­ ment and of the Council of 9 March 2011 ­laying down harmonised conditions for the marketing of ­construction products and repealing Council Dir­ ective 89/106/EEC [3] Directive 2008/98/EC of the European Parliament and of the Council of 19.11.2008 on waste and ­repealing certain directives [4] Verordnung zur Einführung einer Ersatzbaustoff­ verordnung, zur Neufassung der Bundes-Boden-

Dismantling, Recovery and Disposal in Construction

334 39 296 159 10

‡ Concrete ‡ Brick ‡  Lime sand brick ‡  Aerated concrete ‡  Other mineral materials (incl. floor coverings) ‡  Plasterboard, gypsum plaster wall panels ‡  Other gypsum plaster products ‡  Lumber / construction timber ‡  Other wood (incl. flooring) ‡  Sheet glass ‡  Mineral insulating materials ‡  Synthetic insulating materials ‡  Plastic-frame windows /doors ‡  Other plastics (incl. cladding, pipes and cables) ‡  Metals (incl. alloys) ‡  Other materials (incl. pipes, cables and cladding)

30 83 68 119

62

Beton Ziegel Kalksand Porenbet sonstige Gipskarto sonstige Bau-/Kon sonstiges Flachglas mineralis Kunststof Kunststof sonstige Metalle (i sonstige

898

6,389 3,485

15,256 million tonnes

1,232 1,874

179

A 2.14  schutz- und Altlastenverordnung und zur Änderung der Deponieverordnung und der Gewerbeabfall­ verordnung (Ordinance on the introduction of a Substitute Building Materials Ordinance, revision of the Federal Soil Protection and Contaminated Sites Ordinance and amendment of the Landfill ­Ordinance and Commercial Waste Ordinance – draft bill of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety), Bundes­ ministerium für Umwelt, Naturschutz, Bau und Reaktorsicherheit, 06.02.2017   [5] German Waste Management Act (Kreislaufwirt­ schaftsgesetz – KrWG), 24.02.2012   [6] Waste Classification Ordinance (AbfallverzeichnisVerordnung – AVV), 10.12.2001, last amended by Art. 2 of the Ordinance on 22.12.2016   [7] Commercial Waste Ordinance (Gewerbeabfall­ verordnung – GewAbfV), 18.04.2017   [8]  see note 4   [9] Memorandum by the Federal States’ Working Group on Waste Issues (LAGA) 20 – Requirements for recycling of mineral residues / waste – Techni­ cal rules. Part I: General Part. 06.11.2003 [10] DIN 18 007:2000-05 Demolition works – Concepts, procedures, fields of application. May 2000 [11] DIN 18 459:2016-09 German construction contract procedures (VOB) – Part C: General technical specifications in construction contracts (ATV) – Demolition and dismantling works [12] Statistisches Bundesamt, Abfallbilanz 2014. ­Wiesbaden 2016 [13] Author’s own calculations based on “Mineralische Bauabfälle. Monitoring 2014. Bericht zum Aufkom­ men und zum Verbleib mineralischer Bauabfälle im Jahr 2014”. Published by the Initiative Kreislaufwirt­ schaft Bau, c/o Bundesverband Baustoffe – Steine und Erden e. V. Berlin 2017 [14] Author’s own representation, based on “Ökobilanzen rezyklierter Gesteinskörnung für Beton“. Research report by Holcim (Switzerland) AG in cooperation with the Institut für Bau und Umwelt (IBU) and the ­University of Applied Sciences Rapperswil (Hoch­ schule Rapperswil – HSR). Zurich 2010 [15] German Demolition Association (Dt. Abbruch­ verband e. V.) (Pub.) Abbrucharbeiten, 3rd edition. Cologne, 2015 [16] ibd. [17]  see note 10 [18] Müller, Annette – Influence of disposal and person­ nel costs on demolition or dismantling costs. Data­ base: Schultmann, Frank [19] Deilmann, Clemens et. al.: Material flows in build­ ing construction. Building the Future – Research for Use in Practice, Vol. 6, published by the Feder­ al Institute for Research on Building, Urban Affairs and Spatial Development (Bundesinstitut für Bau-, Stadt- und Raumforschung - BBSR). Berlin 2017 [20] Thome, Volker, Fraunhofer IBP, URL: https:// www.ibp.fraunhofer.de/de/Presse_und_Medien / Forschung_im_Fokus/Archiv/Blitz_im_Buero.html. Retrieved on 29.07.2017

Mineral

Other

Output 2010 Input 2010 Output 2030 Input 2030 Output 2050 Input 2050 -150

-100

-50

Output

0

Input

50

100

150

Materials flows [mill. tonnes] A 2.15

Safe disposal ensured Regional landfill requirements: the darker the colouring, the greater the regional landfill requirements in order to prove a ten-year disposal security

A 2.16

23

An Overview of Rating Systems Anja Rosen

Recycling in Building Certification Sustainability certificates for buildings have become firmly established in the property ­market in recent years. Figure A 3.1 shows the countries of origin and distribution of the most frequently used certification systems worldwide. Although general sustainable construction principles based on a three-pillar model of sustainability (economy, ecology, society) have been prescribed in the international ISO 15 392 standard since 2008, there are still major differences in assessments of sustainability. The ­following section describes the ways in which construction using closed materials cycles is anchored in these systems and Figure A 3.2 provides an overview of recycling-related cri­ teria in the most relevant certification systems.

technology, processes and location, depending on the system version. The BNB gives projects a bronze, silver or gold label that reflects the extent to which they meet these criteria. Life cycle assessments Instead of demanding specific measures, ­Germany’s two systems, the BNB and the DGNB, pursue a policy of improving the building’s performance by mapping its effects over its life cycle. In both systems this involves depicting the main environmental impacts, such as emissions and the primary energy requirements of a building to be certified in a life cycle assessment. DIN EN 15 978 [1] states that this must include the modules: •  A Product and construction process stage •  B Usage stage •  C Disposal stage

Aspects of recycling in the BNB system

The sustainably Building ­Ratings System (Be­wertungssystem Nachhaltiges Bauen für Bundesgebäude, BNB) was developed in 2007/2008 by the Federal Ministry of Traffic, Construction and City Development (Bun­ desministerium für Verkehr, Bau und Stadt­ entwicklung – BMVBS) in cooperation with the German Sustainable Building Council (Deutsche Gesellschaft für Nachhaltiges Bauen – DGNB, p. 26f.). It makes use of around 45 sustainability criteria to rate buildings in the six thematic areas of ecology, ­economy, sociocultural and functional aspects,

According to the standard, potential for reutil­ isation, recovery and recycling lies outside the building’s life cycle and is described in module: • D Benefits and loads beyond system boundaries. While module D is rated in the DGNB system, it is currently suspended in the BNB system, where it is calculated and shown for information purposes but not included in the rating. The reason that has been given for this is the lack of basic data for Module D in manufacturers’ environmental product declarations

B

A 3.1 Certification systems worldwide used for buildings, 2017 A 3.2 Recycling-related criteria in established certification systems

24

LEED Round Table Member BREEAM National Scheme Operator DGNB System Partner

A 3.1

Certification System

BNB Office and administrative ­buildings, new buildings 2015

DGNB New buildings 2018

BREEAM International New ­Construction 2016

LEED v4 Building Design and Construction 2016

Site recycling (land and soil)

1.2.4 Land consumption

ENV 2.3 Land consumption

LE 01 Site choice

LT C3 High-priority site SS C2 Site development

Including potential for ­conver­sion, dismantling and recycling in planning

5.1.3 Complexity and optimisation of planning

TEC 1.6 Ease of recovery and recycling

–

–

Disclosure and optimisation of building materials in terms of environmental impact and ­resource conservation

1.1.1 –1.1.5 + 1.2.1 Life cycle assessment – emissions and primary energy requirement 5.2.2 Quality assurance of construction work

ENV 1.1 Building’s life cycle assessment

MAT 01 Life cycle impacts MAT 06 Material efficiency

MR C2 Building product and optimisation – environmental product ­declarations

Further use / reuse of old substance

Only indirectly through a life cycle assessment

ENV 1.3 Responsible use of resources ECO 1.1 Life cycle costs (circular economy bonus)

MAT 03 Responsible sourcing of ­construction products

MR C1 Building life cycle impact ­reduction

Avoidance and recovery of ­ onstruction and demolition c waste (building site waste)

5.2.1 Building site /  construction ­process

PRO 2.1 Building site / construction process

MAN 03 Responsible construction ­practices WST 01 Construction waste management

MR PR 1 Construction and demolition waste management planning MR C5 Construction and demolition waste management

Use of secondary raw materials

–

ENV 1.3 Responsible use of resources

WST 02 Recycled aggregates MAT 06 Material efficiency

Use of renewable raw materials

–

–

–

Absence of pollutants

1.1.6 Risks for the local environment

ENV 1.2 Risks for the local environment

HEA 02 Indoor air quality

MR C4 Building product disclosure and optimisation – material ingredients

Water cycle

1.2.3 Drinking water requirements and wastewater produced

ENV 2.2 Drinking water requirements and wastewater produced

WAT 01 Water consumption

WE Water efficiency

Renewable energy

1.2.1 Primary energy requirements / proportion of renewable primary energy

ENV 1.1 Building’s resources use over its life cycle /proportion of ­renewable primary energy TEC 1.4 Use and integration of building technology

ENE 01 Reduction of energy use and carbon emissions

EA C5 Renewable energy production (cost-based)

ENE 04 Low-carbon design

EA C7 Green power and carbon offsets

End of life

Usage

Planning and manufacture

Phase

An Overview of Rating Systems

MR C3 Building product disclosure and optimisation – sourcing of raw materials

Leasing models for structural components (“Product as a ­Service”)

–

ECO 1.1 Life cycle costs (circular economy bonus)

–

–

Convertibility

2.2.2 Adaptability

ECO 2.1 Flexibility and convertibility

WST 05 / 06 Adaptation to climate change / functional adaptability

–

Cost and effort of disassembly, Strict separation of materials, recyclability

4.1.4 Dismantling, separation and recovery

TEC 1.6 Ease of recovery and recycling

–

–

–

–

–

–

Life cycle assessment of ­recycling potential (Module D)

–

ENV 1.1 Resources the building uses over its life cycle

–

–

Cost of and profit from dismantling, recovery and disposal

–

–

–

–

Abbreviations: C Credit  EA Energy and Atmosphere  ECO Economics  ENE Energy  ENV Environment  HEA Health and well-being  LE Land use and Ecology  LT Location and ­Trans­portation  MAT Materials  MAN Management  MR Material and Resources  PR Prerequisite  PRO Process Quality  SS Sustainable Site  TEC Technical Quality WAT Water   WE Water Efficiency  WST Waste

A 3.2

25

BNB_4.1.4

Foundations, exterior walls, roofs, interior walls, ceilings

Dismantling Separation of ­materials Reutilisation

1. Rating of layer structure

Points 0 2.5 5 7.5 10

− − very unfavourable − unfavourable Ø average + favourable + + very favourable 2. Calculation of recycling factor R R = 0.3 * Points for dismantling  + 0.3 * Points for separation of materials  + 0.4 * Points for reutilisation 3. Weighting by mass [kg]

A 3.3

DGNB_TEC 1.6

Primary /  Support Structure

Envelope

Interior construction

single

double

five-fold

Weighting Structural component group

Support structure

Foundation

Exterior walls

Roofs

Interior walls

Max. points

Ceilings

CE 2 Avoidance (e.g. by dispensing with cladding) CE 1 Reuse or material recovery to create a comparable product

10 20

QS 2 Recycling QS 1 Energetic recovery / backfilling QS 0 Disposal (as hazardous waste) or landfill

45

Easy-to-recover ­building structure

QS 2 Easy-to-recover QS 1 Standard (not explicitly easy-to-recover)

45

Planning process

Dismantlability, convertibility and recyclability in early phases of planning Dismantlability, convertibility and recyclability in construction planning

5 5

Selection of easy-torecycle construction materials

CE (circular economy bonus), QS (quality level)

BREEAM INC 2016 Materials

Waste

Criterion

A 3.4

Max. points

Mat 01

Life cycle impacts

6

Mat 03

Responsible sourcing of construction products

4

Mat 06

Material efficiency

1

Wst 01

Construction waste management

4

Wst 02

Recycled aggregates

1

Wst 05

Adaptation to climate change

1

Wst 06

Functional adaptability

1 A 3.5

26

(see “Type III”, p. 29). The reference values of the BNB system life cycle assessment have been adjusted accordingly. Waste generated during construction The “Optimum use of recycled materials on building sites” indicator in criterion 5.2.1 “Building site / construction process” in the BNB system requires compliance with the statutory minimum standards of the Cycle Management Act (Kreislaufwirtschaftsgesetz – KrWG) and a strict separation of waste during construction. Dismantling, separation and sorting, recovery Criterion 4.1.4 of the BNB system uses three indicators to rate the planning of new buildings to make structures recycling-friendly; dismant­ ling, separation (material purity) and recovery. A tabular catalogue of components records structural elements and their main layers and, based on the three indicators, gives them five different grades ranging from “very unfavour­ able” to “very favourable” (Fig. A 3.3). The grades are not defined in detail. Users can utilise examples of structures that have already been rated as orientation to evaluate the grades. To calculate the rating points for each structural element, the recycling factor R for each element is calculated from the points for dismantling, separation (material purity) and recovery at a ratio of 3:3:4. The product of R and the structural element’s percentage by mass of the whole building gives the number of points for each structural element. The total number of points of all structural elements yields the rating points for criterion 4.1.4, which makes up 4.5 % of the total figure for the ­building. Because the preconditions for using materials within closed cycles have to be secured at the planning stage, the creation of a convertibility, dismantling and recycling concept is included in the process quality [2]. Recycling in the DGNB system

In recent years, the DGNB has further developed its certification system to cover a wide range of building types and applications. Since the launch of the 2018 system version it now explicitly promotes construction using a closed materials cycle with circular economy

An Overview of Rating Systems

3.5 %

Planung 2

‡ Management 2) ‡  Health and well-being 2) ‡ Hazards ‡ Energy 2) ‡ Transport ‡ Water 2) ‡ Materials 1) ‡ Waste 1) ‡  Land use and ecology 2) ‡ Pollution ‡  Surface water run-off +10 % for innovations 1)

Gefahren 10 %

Energie 2 14 %

Transport Wasser 2

7.5 %

Materialie

1%

Abfall 1 12.5 %

Standortö 19 %

with recycling aspects (in the narrow sense) with circular economy aspects (in the broad sense)

2) 

Gesundh

12 %

6.5 %

6%

Umweltve

Oberfläch

8%

entwässe

A 3.6+10 % für In

bonuses. Ten criteria include recycling aspects in the broad sense (Fig. A 3.2, p. 25) and the labels range from bronze (only for previously existing buildings), silver and gold up to platinum. Resource use at the beginning of a structure’s life cycle In 2018, the DGNB system comprehensively expanded its perspective on resource conservation. The reuse of structural components or use of secondary raw materials as an alternative to primary raw materials that have been verifiably responsibly sourced is now rated in the “Responsible use of resources” criterion. This means that insulation made of cellulose from recycled paper, for example, is awarded as many points as wood fibre insulation made of primary materials derived from sustainable forestry (e.g. with an FSC or PEFC label). Easy of recovery and recycling The DGNB takes the recyclability of a building’s components at the end of its usage into account, giving it a weighting of 3 to 3.5 % in the total rating (depending on usage type). The two indicators of “Selection of easy-to-recycle construction materials” and “Easy-to-recover building structure” systematically cover the standard structural components of the building up to the third level of cost group 300 in DIN 276 [3] and from a material and structural point of view. The building materials used are assigned to forms of recycling and reuse based on the hierarchy of the Waste Framework Directive (see “Waste Framework Directive and Waste Management Act”, p. 16) and the forms of recycling and reuse in turn correspond to quality levels with specific point ratings (Fig. A 3.4). Avoiding waste and reducing materials (e.g. by dispensing with cladding), reusing structural components or using materials that can be recycled to make an equivalent product are strategies that are rewarded with circular economy bonuses. A structure is rated as easily dismantlable when it is possible to remove its structural components without destroying them or if layers of structural components can be completely separated without any mixing of materials.

For this rating, the DGNB provides an Excel tool with a catalogue of pre-rated structural ­elements. Groups of structural elements are weighted differently in the rating, depending on their replaceability and the proportion of area they represent. Structural elements outside the overall frame of reference (e.g. building technology) can also be represented in an “Innovation area”, which the DGNB has been using to promote pioneering and/or project-specific solutions since 2018. A third indicator positively rates the inclusion of considerations of dismantlability, convertibility and recyclability in planning. The costs a building incurs over its life cycle Dismantling and disposal costs as well as profits from recycling have not been calculated or rated to date. To take the economic relevance of construction using closed materials cycles into account, however, the DGNB rewards the reuse of structural elements and use of systems that comply with the circular economy concept with bonus points in its “Life cycle costs” criterion. This is designed to promote business models that ensure or substantially support recycling, such as performance contracting (product support services / leasing models) with recovery or recycling strategies [4]. Recycling in the BREEAM system

The Building Research Establishment Environmental Assessment Method (BREEAM) certifi­ cation system is the world’s first rating system for environmentally friendly construction. Developed in 1990 by the British Building ­Research Establishment (BRE), it is run by the UK Green Building Council. BREEAM International New Construction is the BREEAM standard for assessing the sustainability of new residential and non-residential buildings in countries all over the world, apart from the UK and countries with an adapted national BREEAM system. Its ratings range from “classified”, through “good”, “very good” and “excellent” up to “outstanding”. Depending on the ­quality level they achieve, new buildings and modernisation projects are rated on a scale of 1 to 5 stars.

The international BREEAM system for new 1 buildings, whose criteria(im groups are shown in mit Recyclingaspekten engeren Sinn) 2 mitAKreislaufaspekten (im weiteren Sinn)planning Figure 3.6, focuses strongly on the process. This is demonstrated by the fact that the certificate is awarded for two developmental stages – the Design Stage (planning) and the Post-Construction Stage (after completion) – and that several criteria do not rate ­concrete results but the implementation of concepts and management systems. Recycling aspects involving building mater­ ials are included in the eleven criteria groups in the categories of “Materials” and “Waste” (Fig. A 3.5). A life cycle assessment is integrated to some extent in the “Materials” category. The calcu­ lation of a structure’s environmental impact over its entire life cycle (Modules A – C in DIN EN 15 978) is positively rated here, but without linking the results to reference values. Instead, the collection of data is designed to contribute to the development of international benchmark values. The “Responsible sourcing of construction products” criterion positively rates building products rated with BREEAM-recognised ­certification systems such as BES 6001, FSC, EMAS and recycled building products directly. Measures to improve material efficiency, such as the use of recycled materials or strat­ egies for saving materials, are described in the criterion on “Material efficiency”, while ­processes for minimising demolition waste or recycling or reusing it on-site to produce high-quality products and the use of secondary materials as aggregates are rated in the “Waste” category [5].

A 3.3 Rating of the indicators “Dismantling”, “Separation of materials” and “Reutilisation” in criterion 4.1.4 of the BNB system A 3.4 Rating of ease of recovery and recycling in DGNB criterion TEC 1.6 A 3.5 Criteria for the recycling of building materials in the BREEAM International New Construction ­system, 2016 A 3.6 BREEAM International New Construction system, 2016: criteria groups and their weighting for nonresidential buildings

27

1% 6%

Integrale Planung

4%

Lage & Verkehr 2 16 %

Nachhaltiger Standort 2 2 ‡  Integrative process Wassereffizienz Location and transportation 2) ‡  & Energie ‡  Sustainable sites 2) 2 Atmosphäre ‡  Water efficiency 2) Materialien & ‡  Energy and atmosphere 2) 1 ‡  Materials and resources 1) Rohstoffe ‡  Indoor environment quality Innenraumqualität & ‡ Innovation Komfort ‡  Regional priority Innovation 1) including recycling aspects (in the narrow sense) Regionale Prioritäten 2) including circular economy aspects (in the broad sense)

16 % 10 %

13 %

11%

33 %

A 3.7

(Fig. A 3.8) positively rates the disclosure of 1 Leadership in Energy and Environmental environmental impacts by way of using buildKategorien mit Recyclingaspekten (im engeren Sinn) 2 Kategorien Kreislaufaspekten (im develweiteren Sinn)ing products with environmental product Design (LEED) is amit certification system oped in 1998 by the U.S. Green Building ­declarations. In assessing sustainable sour­ Council. Its best-known form is its Building cing, the reuse and use of recycled materials Design and Construction (BD+C) system is equated with the use of products with certifi­version, which applies to new buildings and cates or sustainability reports issued by their comprehensive renovations. Based on the manufacturers. More points can be gained with a declaration of a material’s content that number of sustainability points it achieves, has been audited by a third party. a project is rated in one of four LEED levels: A life cycle assessment can be rated either Certified, Silver, Gold or Platinum. The cri­ qualitatively or quantitatively (Credit 1). A qual­i­ teria and their weightings are shown in Fig. A 3.7. tative rating can apply to the renovation of a From system version v4 (2016), one focus protected historical building, a contaminated of the LEED system has been the transparstructure or the reuse of building materials. ency and optimising of building materials. A quantitative life cycle assessment would be The “Materials and raw materials” category conceivable for building materials so as to

optimise their environmental impact (Modules A to C in DIN EN 15 978). The development and implementation of a waste management plan for minimising construction and demolition waste is fundamentally necessary as a minimum requirement in the LEED system. The results are also quantitatively rated [6].

LEED v4 BD+C

Materials and resources

Max. points

Environmental labels and declarations

Min. requirement

Storage and collection of recyclables

required

Min. requirement

Construction and demolition waste management planning

required

Credit 1

Building life cycle impact reduction

5

Credit 2

Building product disclosure and optimisation – environmental product declarations

2

Credit 3

Building product disclosure and optimisation – sourcing of raw materials

2

Credit 4

Building product disclosure and optimisation – material ingredients

2

Credit 5

Construction and demolition waste management

2

Recycling in the LEED system

A 3.8 C2C criterion: Material Reulitisation

Basic

Defined the appropriate cycle (i.e. technical or biological) for the product. Designed and manufactured for the technical or biological cycle.

˜

Material (re-)utilisation score ≥ 35 % Material (re-)utilisation score ≥ 50 % Material (re-)utilisation score ≥ 65 %

Well-defined nutrient management strategy ­(including scope, timeline and budget) for ­developing the logistics and recovery systems for this class of product or material. Designed and manufactured for the technical or biological cycle. The product is actively being recovered and cycled in a technical or biological metabolism.

Material (re-)utilisation score of 100 %

Bronze Silver Gold Platinum ˜

˜

˜

˜

˜

˜

˜

˜

˜

˜

˜

˜

˜

˜

˜

˜

˜

A 3.9

28

Recycling in Product Certification While rating systems comprehensively scrutin­ ise a building’s quality at the structural level, product ratings concentrate on ecological and social criteria in the manufacturing processes, usage and end-of-life phases of individual building products. The international ISO 14 020 series of standards provides manufacturers and certifiers with guidance on using and providing environmental information on their products on a voluntary basis. There are a number of different types of declaration. Types I and II Environmental declarations as defined in ISO 14 021 (Type II) are voluntary self-decla­r­ ations issued based on the manufacturer’s sole responsibility and can contain details on a product’s recyclate content. In contrast, ­environmental labels as defined in ISO 14 024 (Type I) require certification by a third party. They are of an evaluative nature and set out the particular environmental quality of a product (in an industry comparison), distinguishing it from other products made for the same purpose. The best-known Type I environmental label for products and services of all kinds is the Blue Angel (Fig. A 3.10). Also referred to as an RAL environmental label, it is designed to protect the environment, health, climate, water and resources, although the award ­principles in the “construction” product category focus mainly on minimising pollutants and interior emissions [7]. The building industry-specific Natureplus certificate also imposes resource conservation

An Overview of Rating Systems

A 3.10

requirements, usually rating products with a proportion of renewable and mineral raw materials of at least 85 % by mass. Plastics can be used as additives, but may not form the basis of the product. Raw materials that are available only in limited quantities or costly and complex to extract must be replaced with environmentally friendly secondary raw materials, depending on availability. These basic rules of material design to enable recycling are unfortunately only a recommendation. The required suitability of building materials for processing into equivalent recyclable products is again weakened by the minimum requirement of recyclable materials to generate thermal energy or to dispose of them in non-hazardous landfill [8]. It is notable, for example, that there are no building products made of metal raw materials that are Natureplus-certified, even though they can be practically endlessly recycled. Other relevant Type I environmental labels are the FSC and PEFC labels, which certify wood products from sustainable forestry. Type III Type III environmental product declarations (EPDs) as defined in ISO 14 025 provide complex quantitative and verified information based on a life cycle assessment and quantify a product’s contribution to climate change. Both product-specific and generic data provide a basis for life cycle assessments of buildings and make it possible to rate them comparatively based on reference values. EPDs usually also contain information on the raw materials used, recyclate content and recovery or disposal. In order to implement a circular economy, it will, in future, be necessary to compulsorily demonstrate the benefits and any pollution arising from recycling (Module D in DIN EN 15 804). The materials cycle concept in the Cradle-to-Cradle system

Cradle-to-Cradle certification follows a production method from “cradle to cradle” (C2C), in contrast to the “cradle to grave” model. This certification programme, which was developed in 2005 by German chemist Michael Braungart and American architect and designer William

McDonough, can be applied to any kind of product made using the principles of cradleto-cradle design. Around 500 products have been awarded a C2C certificate worldwide so far, more than 350 of them in the building products and fittings group [9]. “In nature, there is no concept of waste. Everything is effectively food for another organism or system.” [10] This principle, which follows the maxim of eco-effectiveness, involves defining all the materials in a product as nutrients and assigning them either to the biological or technical cycle (Fig. A 3.11). Rating methods and processes Cradle-to-Cradle certification rates products based on five categories, and the extent to which products fulfil the categories’ requirements are recorded in a “scorecard”. In Fig. A 3.9 the requirements of the Cradle-to-Cradle Certified Product Standard (V 3.1) [11] for the criterion of “Material Reulitisation” are assigned to the five ratings of Basic, Bronze, Silver, Gold and Platinum. Four further criteria are rated in the same way: “Material Health”, “Renewable Energy and Carbon Management”, “Water Stewardship” and “Social Fairness”. Constituent and material reulitisation The fundamental principle of the C2C certification process is the identification and definition of the contents of the product to be certified. Toxic substances are excluded to protect the health of users and to prevent pollutants from accumulating in the biosphere due to recycling. Material recycling is a key component in the C2C system. As well as strategic aspects for implementing material flow management, the product’s recycling rate mainly counts in the rating. This is identified based on the proportion of recyclable or compostable materials and the proportion of already recycled or renewable raw materials at a ratio of 2:1 as follows: 2≈ % of product recyclable or biodegradable / + compostable 3

% recycled or rapidly renewable product content

A 3.11

An example of a project that used this approach In early 2018 a Cradle-to-Cradle-inspired building was completed in Essen. The new administration building was built on a rehabilitated area of the former coking plant of the erstwhile Zollverein coal mine, which is now a World Heritage site (Fig. A 3.12). Its walkable green roof landscape partly compensates for areas sealed due to the construction measures. As part of the EU’s “Buildings as Material Banks (BAMB)” research project, the materials used were documented in a “Materials Passport”. Structural components in contact with soil were built mainly of a concrete that is impermeable to water without additional sealing, and the opaque exterior walls were clad with aluminium sheeting. The band of windows is made of a C2C-certified glazing system (see “Glazing and space between panes”, p. 96f.).

A 3.7

LEED Building Design and Construction system (BD+C) v4: Criteria groups and their weighting A 3.8 Criteria of the “Materials & raw materials” group in the LEED Building Design and Construction system (BD+C) v4 A 3.9 Rating of materials recycling in the Cradle-toCradle system A 3.10 Type I established environmental labels for construction products A 3.11 The Cradle-to-Cradle system: biological and technical materials cycles A 3.12 C2C-inspired new building. Administrative building, former Zollverein coal mine, Essen (DE) 2018, kadawittfeldarchitektur

x 100 A 3.12

29

Conclusions and Prospects

Compatibility with recovery and reuse

So far, building certification systems tend to rate recycling aspects mostly in terms of ­quality. Recycling potential is currently not quantitatively rated and life cycle assessments only inadequately evaluate recycling potential. The economic relevance of recycling in certification systems has so far attracted either no or insufficient interest. Although the two German systems calculate and rate life cycle costs (LCC), they currently still do not take into ­acccount the costs of the end-of-life phase in terms of dismantling and disposal or recovery. This may be due to a lack of fundamental data on end-of-life phase costs. The reasons often given for ignoring these aspects are that dismantling and disposal costs are left out because they represent such a small proportion of total life cycle costs. Given the increasing shortage of resources and growing disposal costs, this is sending the wrong signal. In fact, end-of-life costs are not sufficiently weighted due to the current cash value method used to calculate life cycle costs. A discounted interest rate above the rate of price increases, 5

+ Easily separable – Separate recovery and reuse

– Hard to separate – Hard to recover and reuse

4

3

Modular Detachable

2

Compatible with recovery and reuse

together with the long periods elapsing until dismantling occurs, means that subsequent ­dismantling and disposal costs are not rated highly, which creates a distorted view of the actual costs involved. The hitherto neglected economic potential of recycling is described in the section on “Cost Comparisons of Conventional and Urban Mining Design Constructions” (see p. 120ff.) and explained based on three examples. Researchers are currently working intensively on measuring the recyclability of structures. The Institute for Lightweight Structures and Conceptual Design (Institut für Leichtbau, Entwerfen und Konstruieren – ILEK) at the ­University of Stuttgart has developed a scientific method for analysing recyclability in detail that takes joining techniques into account. The ILEK RecyclingGraph Editor describes structural element structures in recycling graphs whose components represent their material elements and connections (joints) [12]. Their materials are shown as squares and the joints between the materials as ellipses (Fig. A 3.14 a, b). To identify the best form of recycling, materials are each classified in a five-level scale based on a system developed by the Austrian Institute for Healthy and Ecological Building (Institut für Bauen und Ökologie – IBO) [13] that measures their Compatibility with recovery and reuse

C2C-certified carpets and ­parquetry were used as floor coverings (see “Floors, ceilings: surfaces”, p. 84f.).

4

a

30

3

3

C4–C7 C10

C1 C2 C8 C9

2

C14–C16

4

1

b

Jointly rating recoverability and recyclability and detachability enables the dismantling methods necessary for recycling to be determined (Fig. A 3.13 a, b). The ILEK RecyclingGraph Editor can show complex connections in a structured way so it would seem to be a suitable basis for digi­t­ alised construction methods (see “Using BIM to Optimise Materials Cycles in Construction”, p. 32f.). A system that responds to current planning practice and was used in the examples of structures in the “Detailed Catalogue” (p. 135ff.) in this book for rating the recycling potential of structures is explained in the ­chapter on “Assessment of Loop Potential” (p. 114ff.).

C3

C1–C13

5 Detachability (from non-destructive to detachable after destruction) 2

The interrelated joints of materials are shown in a joint matrix (Fig. A 3.14 c) and rated in a way similar to that used in existing manufacturing and engineering standards (DIN 8580 [14] and DIN 8593 [15]) based on two criteria (also in five levels): •  Recoverability and recyclability of materials •  Detachability of joints

5

– Hard to separate + Easily separable + Joint recovery and reuse + Joint recovery and reuse

1

• recyclability, •  potential for incineration, and •  potential for landfill disposal.

2

3

4 5 Detachability A 3.13

A 3.13 Classification of detachability and recyclability and reusability of materials pairs (based on Schwede /Störl) a Legend /Explanation b Rating of a concrete wall with composite ­thermal insulation (C1– C16 = Numbering of joining principles) A 3.14 ILEK RecyclingGraph Editor: Structural component structure, Recycling graph and joint matrix for steel-reinforced concrete wall with composite thermal insulation (based on Schwede /Störl) a Structural component structure b Recycling graph c Joining matrix

An Overview of Rating Systems

M 1 M 2 M 3 M 4 M 5 M 6 M 7 Notes:   [1] DIN EN 15 978:2012-10 Sustainability of construction works – assessment of the environmental perform­ ance of buildings, calculation method. German version of EN 15 978:2011   [2] Federal Ministry of the Interior, Building and Community: Assessment system for sustainable building (BNB), office and administration building – new building, version 2015, URL: https://www.bnb-nachhaltigesbauen.de/bewertungssystem/bnb-buerogebaeude/bnb-bn-2015/kriterien-bnb-buero-undverwaltungs­gebaeude-neubau.html. Retrieved on 21.07.2018   [3] DIN 276-1:2008-12, Building Costs – Part 1: Building construction   [4] German Sustainable Building Council (Deutsche ­Gesellschaft für Nachhaltiges Bauen – DGNB) e. V. (Pub.): DGNB System. Criteria set new construction building, version 2018   [5] BRE Global Ltd. (Pub.): BREEAM International New Construction 2016. Non-domestic buildings. technical manual, SD233 1.0   [6] U.S. Green Building Council (Pub.): LEED v4 for Building Design and Construction (BD+C), URL: http://www.usgbc.org/resources/leed-v4-buildingdesign-and-construction-current-version, as of 04/2016. Retrieved on 12.11.2016   [7] RAL gGmbH / Blauer Engel (Pub.): Vergabekriterien. https://www.blauer-engel.de/de/fuer-unternehmen/ vergabekriterien, retrieved on 31.10.2017   [8] Natureplus e. V. (Pub.): Vergaberichtlinie 0000, ­Basiskriterien, as of 05/2011   [9] Cradle-to-Cradle Products Innovation Institute. http://www.c2ccertified.org/products/registry, ­retrieved on 30.10.2017 [10] McDonough Braungart Design Chemistry LLC: ­Cradle-to-Cradle CertifiedTM Product Standard, ­Version 3.1, 2016 [11]  see note 10 [12] Schwede, Dirk A.; Störl, Elke: Method for analysing the recyclability of building structures. In: Bautechnik 94 (2017), H. 1, p. 1– 9 [13] Austrian Institute for Healthy and Ecological Building (IBO – Österreichisches Institut für Bauen und ­Öko­logie) (Pub.): EI – Disposal indicator, guide to calculating the disposal indicator of components and buildings. Vienna, 2012 [14] DIN 8580:2003-09, Manufacturing processes – terms and definitions, division [15] DIN 8593-0:2003-09, Manufacturing processes ­Joining – Part 0: General, classification, subdivision, terms and definitions

M 8 Reinforcing mortar, 3 mm M 9 Primer M 10 Silicone resin plaster, 3 mm M 11 Steel reinforcement mesh M 12 Insulating fixing, plastic, 200 mm, ­diameter 60 mm M 13 Anchor plate cover, EPS, 15 mm

Emulsion paint Plaster filler, 3 mm Concrete, 180 mm Adhesive mortar, 5 mm EPS insulation, 140 mm Reinforcing mortar, 2 mm Reinforcement fabric, glass fibre

M11

M5

M6

M7

M8

M10 M9

a

M13

M1

M1

M1

M11

C10

C1

M1

M2

M2

C2

M3

M3

M4

C3

C11

M4

C12

M12

C4

C13

C14

M5

C15

M13

C5

C16

M6

M2

M3

M4

M4 M12

M5

M6

M7

M8

M9

M10 M11 M12 M13

C1 C1

C2 C2

C3 C3

M5

C10 C4

C4

M6 M7

C13

M8

C7 C7

M9

C8 C8

C6

M11

C10

C7

M12

C11

M8

M13

C15 C16

C6 C6

M7

C11 C12

C5 C5

M10

C8

M2

M3

C9 C9

C12

C13 C15

C14 C16

C14

c

M9 C9

M10

b

Materials (M1, etc.) are shown as squares, as are joining materials, e.g. dowels. Colours represent materials groups with the same colours. Joining principles (C1, etc.), e.g. frictional connections, are immaterial and shown as ellipses. The darker the ellipse’s colour, the harder the joint is to detach. A 3.14

31

Using BIM to Optimise Materials Cycles in Construction Manfred Helmus, Holger Kesting

The digitalisation of Germany’s economy has been progressing swiftly in recent years and the BIM method has been a leading driver of this progress in the construction industry. “Building Information Modelling is a way of integrating and networking all a building’s ­relevant data in a virtual data model that ­covers its entire life cycle, from its concept and design, planning and construction, right through to usage and dismantling.” [1] In using the BIM method, it is necessary to describe related processes to collate all the information relevant to recycling. This ­information is recorded as a separate pro­ cess and modelled and combined using the BIM method, so that the resulting data is consistent. Life Cycles The life cycles of buildings and construction products are the basis for the processes described below. Buildings’ life cycles

The process flow involved in creating a build­ ing is divided into development, planning, ­construction, operation and demolition (Fig. A 4.1). For new buildings, information ­relevant to recycling is fed in primarily for ­construction and in some cases for conver­ sion measures. Construction product life cycles

Cycle phases also form the basis for describ­ ing the processes that a building material undergoes. These phases are divided into raw material, production, processing, usage, dismantling, disposal and recovery (Fig. A 4.1). Materials cycle: building – construction product To optimise the materials cycle, the two life cycles, that of the building and that of ­construction products, must be merged

32

(Fig. A 4.1). Here there are overlaps in the construction, operation and demolition phases. Any overlaps can be worked out based on this method. As can be seen in ­Figure A 4.2, “demolition” is the process in the building’s life cycle most interdepend­ ent with the processes of “dismantling”, “recovery”, “disposal” and “manufacture” in the construction product life cycle. To ensure such conclusions, consistent infor­ mation on building materials and a high degree of detail is essential. Successful use of BIM for recycling also requires the provi­ sion of the necessary data profile during ­construction. Only then can the main pro­ cesses of creating documents on build­ ing materials be identified, documents (out­ puts) such as declarations of performance, safety data sheets or delivery notes. These are incorporated as input into other pro­ cesses, including across different life cycles, allowing both classifications and initial ­connections between relevant processes to be made. In the next step, the detailed information obtained must be processed by determining the type of declared perform­ ance, i.e. characteristics of construction ­products. The information required for ­dismantling and conversion must then be compared with the information profiles in the documents stored in the BIM model. In Europe, the data profiles of construction ­products and materials are subject to various ordinances and standards. These are mainly construction product-specific requirements in the certificate of conformity. An Example: Recycled Aggregate Made of Concrete and Sand-Lime Brick This example of the use of recycled aggre­ gates in concrete is designed to provide an exemplary survey of whether it would be pos­ sible, using the information on concrete and sand-lime brick now required to be docu­ mented for new buildings, to return crushed building rubble to the concrete product cycle

Using BIM to Optimise Materials Cycles in Construction

Life cycle: building

Life cycle: construction product

Raw material Demolition

Production

Development

Recovery Operation

Processing

Planning Disposal Dismantling

Construction a

Usage

b

without further testing. In this example there are delivery notes (outputs from a process already described) for recycled concrete in accordance with DIN-EN 206-1. This is not the case for recycled sand-lime brick. As a har­ monised construction product as defined in DIN EN 771-2, declarations of performance and safety data sheets are available from which information for the production of recy­ cled aggregates for concrete can be obtained. Following the German Committee for Struc­ tural Concrete Guideline (DAfStb-Richtlinie) [2], the material composition of recycled aggregates is classified into concrete chip­ pings (Type 1) and crushed building rubble (Type 2). Crushed concrete and brick or ­sand-lime brick are the main constituents of recycled concrete. The Guideline contains details on the requirements imposed on recyc­ led aggregates for use in concrete. Depending on the main constituents of recyc­ led aggregates, details on the relevant requirement parameters can be obtained from the certificate of conformity. Here it must be noted that the values provided in certifi­ cates of conformity for the construction prod­

A 4.1

ucts used are only of limited significance in respect of the requirements imposed on the recycled aggregates and do not contain all the necessary information. Therefore, the data that is fed in contains only some of the information that must be directly included as input in the process modelling to optimise materials streams with the help of BIM. This lack of data means that, at the moment, add­ itional materials testing must be carried out if crushed building rubble is to be used as a recycled aggregate. Based on the consistent process modelling of construction products that takes the life cycles of buildings and construction prod­ ucts into account, digital standards for the provision of information documents can be developed and applied, enabling the BIM method to be used to optimise materials cycles. At the same time, it has been shown that the data profiles currently in BIM models are not yet detailed enough to enable consist­ ent recycling. For BIM-based urban mining this means that an additional information basis optimised to accommodate recycling need to be created and included in the digital standards.

A 4.1 Life cycle phases and main processes a  Building b  Construction product A 4.2 Overlapping of life cycle phases of the building with those of construction products

Notes: [1] Meins-Becker, Anica; Helmus, Manfred; Sigmund, Bettina: BIM: Entwicklungsstufen und Prozesse, 09.02.2017. http://www.detail.de/artikel/bim-entwick­ lungsstufen-und-prozesse-29460/. Stand 03.07.2017 [2] Deutscher Ausschuss für Stahlbeton, DAfStb-Richt­ linie: Beton nach DIN EN 206-1 und DIN 1045-2 mit rezyklierten Gesteinskörnungen nach DIN EN 12 620, Entwurf 09/2010 The research project “Building Information Modelling (BIM) as a basis for using digital information to optimise materials cycles in construction” (“Building Information Modeling (BIM) als Basis für den Umgang mit digitalen Informationen zur Optimierung von Stoffkreisläufen im Bauwesen”), funded by the German Federal Environmen­ tal Foundation (Deutsche Bundesstiftung Umwelt – DBU)

Life cycle Building

Production

Life cycle Construction product

Construction

Operation

Processing

Usage

Demolition

Dismantling

Recovery

Production

Disposal

A 4.2

33

An Elastic Standard – Urban Mining and Computational Design Holger Hoffmann

“The blossoms on the apple tree are standardised, but they are all different. In the same way we ought to learn how to build.” [1] Computer-aided planning tools offer various advantages in enabling the successful, continued use of structural elements from future buildings. On the one hand, a digital “twin” of the analogue building (Building Information Modelling – BIM) makes it easier to both identify the elements used and to (re) produce new elements in order to keep a building standing, for example (see “Using BIM to Optimise Materials Cycles in Construction”, p. 32f.). This does, however, make a precise digital description, not only of the elements’ geometry, but also of their joints, proportions and characteristics, indispens­able (Fig. A 5.1). On the other hand, computer-aided parametric or computational design replaces tech­ nical and methodological standardisation with specification. While architects in the modernist Neues Bauen movement in the 1910s to 1930s aimed at the “identical reproduction” [2]

of structural elements by industrial means, contemporary digital planning and manu­ facturing methods allow planners to create far more individualised structural elements. Every geometry in CAD/BIM software is described numerically, so it is basically parametrically adjustable or “elastic”. The form of a “component”, as structural elements are called in digital discourse, is not absolute (as the pieces in a chess game are), but relational (like the stones in the strategic board game of “Go”), and is determined by the elem­ ents’ relationships. Alvar Aalto’s concept of an “elastic standard” as a further development of functional mod­ ernity’s efforts at rationalisation is as current today as it was then. Computer-Aided Manufacturing (CAM) can now be used to very ­easily vary components’ geometries, optimise the quantities of materials required to build a structure and improve the performance of joints between structural elements and can open up a wealth of forms that were once fixed and exclusive features of the discipline of

A 5.1

34

An Elastic Standard – Urban Mining and Computational Design

A 5.2

­ rchitecture before construction was indus­ a trialised (Fig. A 5.2). Considered at the superficial level, more ­differentiated structural elements might initially be seen as problematic for an urban ­mining approach, since it seems more expe­ dient to find and design a series of components that are as similar as possible and ­universally ­usable, elements that could be ­subsequently translated into uniform new structures that would be as homogeneous as possible. This kind of “modernistic” approach regards components as undifferentiated “building blocks”, as abstract and featureless as possible. Such a 1:1 use of components would, however, be a special case. More typically, geometric adjustments through subtractive processes and the integration of precisely made connections in a new design are necessary because requirements, standards and manufacturing processes have usually changed greatly in the period between a component’s original installation and its recovery when the building is dismantled at the end of its life cycle. This difference opens up new aesthetic possibilities in the application of parametrically adjustable and generative building models in urban mining processes. A comparison of available components (existing structure = “current state”) with a target form (design = “target”) through an iterative and evolutive adjustment process yields similar yet varying solutions. In this process the great potential of parametric tools, namely the simple creation of variants for investigating different perform­ ance criteria, replaces the linear adjustment process described above, which traditionally aimed to make the result as congruent as possible (“identicality”) with the originally planned object (Fig. A 5.3). In contrast, possible solutions as non-linear series that can be optimised in at least two directions (“target” and “current state”) are now being further developed, so the characteristics of available components and possi­ bilities arising from their manufacture and joining are being integrated in the structure’s final design [3]. The “bottom-up” strategies inherent in parametric and generative design processes

can do more than expediently manage the continued use and transmission of used materials. Using digital design tools in urban mining also caters to a contemporary aesthetic of the fragmentary; not in the sense of a traditional collage, into which elements are inserted unchanged, but in the sense of a seamless collage, in which the reused components retain their identity.

Notes: [1] “Die Blüten auf dem Apfelbaum sind standardisiert, sind aber alle verschieden. Auf die gleiche Weise sollten wir lernen, wie man baut.” Schildt, Göran: ­Interview with Alvar Aalto. In: Fleig, Karl: Alvar Aalto. Das Gesamtwerk, Vol. 1. Basel 2014, p. 232 [2] Carpo, Mario: The Alphabet and the Algorithm. ­Cambridge 2011, p. 4 [3] One project that almost ideally implements and ­illustrates these kinds of processes is Certain Mea­ sures’ “Mine the Scrap” software, which uses digital pattern recognition to investigate the forms of randomly collected scraps of materials and in generative processes approximates predefined forms, in this case a cube.

A 5.1 “Treehugger”, BuGa 2011, Koblenz (DE) 2011, Trier University of Applied Sciences and one fine day. Its largely modular structure meant that after the German national ­garden show (Bundesgartenschau) was over, the Treehugger Pavilion could be disassembled and rebuilt elsewhere. Any missing structural components could easily be remanufactured based on a 3D model. A 5.2  “Mine the Scrap”, Certain Measures, 2015 /2016 A 5.3 “folly@HC2”, 2017. For this project involving students from the University of Wuppertal (Bergische Universität Wuppertal), Lehrgebiet Darstellungsmethodik und Entwerfen (school of presentation methodology and design), the series of components to be manufactured were compared in terms of their structural performance, creation of space and aesthetic, depending in particular on the production possibilities available in the subject area.

A 5.3

35

Eco-Efficient Construction Using Local ­Resources Thomas Matthias Romm, Thomas Kasper

Resources on the Building Site, the Genius Loci Controlling flows of materials in construction is an essential activity in the context of environ­mentally effective, cost-efficient building materials and construction site logistics. In the past 20 years, demand for mineral building ma­terials worldwide has tripled [1]. Secondary raw materials, i.e. materials obtained through recycling, can meet only part of this demand. These materials cannot solve resources problems, but they could contribute to a solution. 80 % of the materials needed to construct a building are required for earthworks and the building’s shell. Excavated earth, for example, is usually removed from building sites. In Germany only some of this excavated earth has to go into landfill; 75 % of it can potentially be utilised. Sand, gravel and concrete ­usually arrive at building sites after being transported over an average distance of 15 to 30 km. In many cases, sandy gravel from excavated earth could be turned into aggregates for concrete on-site without much effort. Major construction projects clearly reveal the increased added value of on-site raw materials production in construction. The building of railway stations, highways and tunnels requires efficient materials logistics that aims to optimise supply and disposal by means of processing and balancing earthworks. This demands both precise planning of materials flows and management of their logistics on site. Analysis instruments and measures

A 6.1 Start of construction work in 2014 in Aspern ­Seestadt, Vienna showing building materials processing on site. A 6.2 Circular economy on a building site: Construction that dispenses with large-scale soil excavation (waste reduction), reuse of structural components and recovery and recycling of building materials sourced on the building site (on-site recycling)

36

Logistics planning for the use of local resources in construction management materials flows is based on an analysis of the materials’ qualities. A survey of pollutants and impurities assesses the permissible reuse of materials resulting from a demolition before a construction project starts and the geotechnical survey reports and survey reports required by laws on waste regulate the use of excavated earth. Soil classifi­cation for construction purposes as defined in DIN 18 196 determines the extent to which soil can be used as a building material. Local use of excavated earth minimises landfill volumes, preserves resources extraction sites, and greatly reduces heavy vehicle traffic.

Soils that are less valuable for construction ­purposes can also be included in planning in the form of balancing earthworks. Backfilling and terrain modelling in open spaces often offer possibilities for a predictive mass balance, although this is frequently not possible without further processing for cohesive soils and nutrient-rich topsoils. Here, crushed brick and other lightweight water-retaining aggregates (e.g. expanded clay or aerated concrete) from a demolition can be used to optimise the properties of soils. Recycled materials, used on green roofs, for example, can improve the resilience of residential areas in coping with the effects of climate change such as global warming and torrential rainfall events by enhancing the soil’s ability to retain water. Laying this kind of vegetation substrata reduces rainwater discharge and can be part of decentralised flood protection measures. These kinds of green spaces also make urban areas more resilient in long, dry periods. Building materials recycled on-site have a more positive impact in a life cycle assessment than primary raw materials, because they do not need to be transported. This makes recoveryoriented dismantling before a construction ­project begins an important factor in the successful strategic planning of resource use with ­processing infrastructure on the building site (Fig. A 6.2). Materials from the dismantling of buildings and site soil can be regarded both as raw material deposits on a building site and as part of the “genius loci”, so on-site processing and balan­ cing earthworks are crucial instruments in sustainable mass flow management. The EU Waste Framework Directive defines excavated earth that is reused on site as “not waste”, unlike excavated earth that is removed from a building site. This has a range of legal consequences (see “The Legal Background”, p. 16ff.), so using excavated earth on the site it has been extracted from also has advantages in terms of compliance with waste management legislation. For some years, this fundamental knowledge has been successfully put into practice in large-scale construction projects in Vienna, one of Europe’s fastest growing cities.

Eco-Efficient Construction Using Local ­Resources

A 6.1

The “Vienna Model” The “Vienna Model” is the systematic approach that the Austrian capital uses to secure costeffective construction and affordable housing in Vienna, an “environmental model city”. A thoughtful use of resources is part of this quality assurance, which, despite the doubling of annual production to 10,000 residential units in the past 20 years, guarantees a high degree of sustainability. Challenges such as climate change (increasingly frequent torrential rain events and long dry periods) and population growth resulting from mass migration must be met with sustainable strategies. An urban mining concept that aims to maximise recyc­ ling rates in building projects is a good way of increasing the environmental efficiency of construction work (see “Circularity in Archi­ tecture – Urban Mining Design”, p. 10ff.). ­Balancing earthworks over a number of building sites and the efficient use of resources in individual construction work steps are both anchored in a large-scale urban development project master plan. The large-scale construc-

tion sites of Vienna’s new central railway station and the former Aspern airfield site, where the “Seestadt Wien” with apartments for 20,000 ­residents and thousands of workplaces has been built since the master plan was adopted in 2007, are current examples of this kind of successful resource planning in urban development and its implementation on building sites. Urban mining has now become firmly established in construction at the large-scale project development level. This reflects the local government’s policy decision to improve the building industry’s business and management strat­ egies through development designed to benefit the wider public over a number of building sites. This type of recycling strategy is consistent with the EU Waste Framework Directive demand (see “The Legal Background”, p. 16ff.) that waste be avoided. In Vienna it emerged out of a decades-long dialogue between the public sector and the building industry that had its origins in the joint development of their Guidelines for Sustainable Construction Site Management (Richtlinien für umweltfreundliche Bau­stellenabwicklung or RUMBA).

Sustainable mass flow management aims to obtain most of the building materials required from the construction activity itself. The preconditions for this include the specifications of the urban development master plan, which forms a basis for zoning. Among the key factors for successful on-site recycling are the detailed planning of materials flows for balancing earthworks within the building area and logistical implementation of local recovery and recycling during the construction phase. BIM (Building Information Modelling) is used to analyse materials in the recovery-oriented dismantling of buildings. A preceding survey of any pollutants and impurities results in a ­dismantling plan that provides a quantity structure. The materials flows expected from the ­dismantling are classified according to their recoverability and recycling and processing on the building site is included in the demolition contract. This matrix quantifies applications for crushed materials by sieve fraction, such as technical filling material, roadbed, drainage material and aggregates as substrata for plants. The structure of angular crushed rubble,

Recycling-oriented dismantling Mobile excavation processing Demolition by machine Local building materials Mobile crushing plant Mobile concrete plant

A 6.2

Kreislaufwirtschaft auf der Baustelle

37

A 6.3

A 6.4

A 6.3 On-site concrete plant in Aspern with gravel ­processing A 6.4 Aspern Süd master plan, Vienna (AT) 2006, ­Master plan: Tovatt Architects & Planners with N+ Objektmanagement A 6.5 On-site concrete concept: All types of concrete and all the in-situ concrete required was produced entirely on site. Using a closed system that is not dependent on groundwater, the plant operator processes aggregate fractions using wet processing to make high-quality types of ­concrete (higher than XC1). A 6.6 Aspern Süd site at the start of building with the construction logistics centre 2014

38

for example, means that it is usually ideal for civil engineering applications. Mobile machines can process gravel and sand from pit excavations into concrete on-site. The materials are screened, crushed and classified as aggregates for concrete on-site (Fig. A 6.3). Based on a BIM evaluation of soil analyses to assess the soil’s geotechnical properties and compliance with waste management legislation and taking the volume of extracted earth into account, it is possible to forecast the potential extent of local recovery and recycling (Fig. A 6.5). Gravelly sand that is further processed after simple dry screening can be used in 50 % of the concretes commonly used in building construction. Wet processing that is not depen­ dent on groundwater can also be used for this purpose. All qualities of concrete can be made on-site out of these washed aggregates. This process is ecologically as well as economically effective. On-site recycling, direct recycling in situ, makes for shorter construction times, saves transport and disassembly costs, and reduces a structure’s environmental impact. The principle of “recovery and recycling instead of transport” has an enormous environmental impact. Two-thirds of inner-city freight transport is to and from building sites [2] and heavy vehicle transport causes a large proportion of local fine dust particle emissions. Intelligent recovery and recycling logistics on building sites reduces emissions such as airborne pollutants, noise, and fine dust while optimising cost benefits and giving rise to a cyclical process that covers dismantling, earthworks and the construction of the building’s shell, offering the building industry new business models. The two forward-looking building projects described below are examples of successfully implemented urban mining. Project example – Vienna’s Aspern Seestadt

Aspern Seestadt is one of the world’s largest urban development projects, covering 240 hectares (Fig. A 6.6). The project development company has supported urban mining since construction began, setting up a logistics subsidiary specially for this purpose. A case study shows how more than one million tonnes of mater­ial was locally processed and used in the ­construction of the first 3,000 apartments. Balancing earthworks – the raising of the ground

elevation level for road building – enabled the volume of excavated earth to be halved and excavated earth material to be used in road building and as aggregate for concrete. All the grades of concrete and all the in-situ concrete required were produced exclusively using local gravel directly on the building site (Fig. A 6.5). The plant was designed to produce a peak output of 2,000 m3 of concrete and in fact achieved this daily output several times. All the types of aggregate were processed using a closed wet processing system that was not dependent on groundwater. Only 5 % of the washing water adhering to the gravel was fed back into the water cycle. Despite the cost and effort involved in management and quality assurance, a bill of quantities calculating the extra costs and reduced costs revealed clear economic advantages that did, however, vary from building site to building site and resulted from the savings obtained from reduced transport mileage and better availability of raw materials. Project example – “Biotope City”

Another case study examined the ambitious “Biotope City” residential project, a dense yet very green development of around 1,000 residential units on the site of a former production plant in Vienna, whose 50,000 m2 area had been completely built over and sealed. Here, an urban mining approach was used to support the goal of creating a resilient habitat that would adapt to the consequences of climate change and allow for high levels of biodiversity in the city by providing a consistent maximum greening of facades and roofs and unsealed open spaces. The strategy centred on using plant and soil substrata for the long term and on the near-natural greening of buildings and open spaces that require very little care and maintenance. The use of partly locally-sourced secondary raw materials make it possible to retain more water [3]. The University of Natural Resources and Life Sciences, Vienna (Universität für Bodenkultur Wien) hosted accompanying research programmes and has issued scientific publications on this topic [4]. For this pilot ­project, the value creation as well as the recovery and recycling of structural components is achieved via a cooperative network of socio-economic enterprises, covering everything from recycling through to re-use and

Eco-Efficient Construction Using Local ­Resources

going well beyond merely managing materials flows in the area under construction itself.

300,000 m³ lake excavation

Conclusion: legal aspects

Three legislative aspects must be emphasised in highlighting the “Vienna Model” as implementing European circular economy principles in construction. The first of these is the top ­priority of avoiding waste. The EU Waste Framework Directive does not classify as waste excavated soil ma­terials that are reused where they are extracted. This exception absolves builders from compliance with a further series of legal obligations involving waste treatment – whether in disposing of it in landfill or recovering and ­re-using it elsewhere. From a European law perspective, using waste for the production and utilisation of recycled building materials is also necessary in terms of two other aspects. On the one hand there is the obligation of EU member states prescribed in the Waste Framework Directive to comply with a recycling rate of 70 % for non-hazardous construction and demolition waste by 2020. On the other hand, there is the EU Construction Products Regulation, which prescribes the use of secondary raw materials for every new building (see “The Legal Background”, p. 16ff.).

Notes: [1] The United Nations Environment Programme (UNEP) does not have reliable data on output quantities of mineral building materials for all regions of the Earth, so the amount is deduced indirectly from data on ­cement production, which tripled in the period from 1994 to 2012. https://wedocs.unep.org/bitstream/ handle/20.500.11822/8665/GEAS_Mar2014_Sand_ Mining.pdf?sequence=3. Retrieved on 07.06.2019 [2] Guidelines for sustainable construction site management, final technical report, EU-LIFE research project, project number LIFE00 ENV/A/000239. Published by the MD-Stadtbaudirektion of the City of Vienna (Stadt Wien). Vienna, 2004, http://www.rumba-info.at/files/ kurzbericht_rumba_englisch.pdf. Retrieved on 07.06.2019 [3] e.g. the production of roof substrata based on compost and brick chippings in recycling plants. https:// www.optigreen.co.uk/products/substrates/. Retrieved on 07.06.2019 [4] https://forschung.boku.ac.at/fis/suchen.projekt_ uebersicht?sprache_in=en&ansicht_in=&menue_id_ in=300&id_in=11057 https://forschung.boku.ac.at/fis/suchen.projekt_ uebersicht?sprache_in=en&ansicht_in=&menue_id_ in=300&id_in=11208. Retrieved on 07.06.2019

Wet processing Not dependent on groundwater Closed system

Dry processing Electric-powered Screening and crushing plant

On-site concrete plant Output 200 m³/h

A 6.5

A 6.6

39

Part B  Construction and Materials

1  Detachable Connections and Constructions Foundation: Footings, Cellars Support Structure Exterior Coverings: Walls, Pitched Roofs Exterior Floor Coverings: Flat Roofs, Roof Terraces Interior Walls  Interior Wall Facing  Floors Windows and Exterior Doors, Post-and-Beam Constructions

42 46 48 49 50 52 52 53 56

2  The Recycling Potential of Building Materials Conserving Resources and Avoiding Waste Examples of Materials: Fundamentals and Evaluation  Foundations and Support Structures Exterior Walls, Pitched Roofs: Exterior Surfaces Flat Roofs: Exterior Surfaces Wall, Ceiling, Roof: Structural Panels for Exteriors and Interiors Walls, Ceilings: Interior Surfaces Floor Structures  Floors, Ceilings: Surfaces Insulation Seals and Separating Layers Openings and Glazing Units  3  Mono-Material Construction Biotic Materials: Timber Mineral Building Materials: Loam, Brick, Aerated Concrete, Insulating Concrete  Conclusion and Prospects

58 58 64 65 72 79 80 83 84 84 86 92 95 102 102 104 106

4 Can Loop Potential Be Measured? An Analysis Using Facade and Roof Coverings as Examples Loop Potential as a New Architectural Parameter Criteria for the Assessment of Loop Potential Facades Roof Coverings Conclusions

108 108 108 108 110 111

5  Assessment of Loop Potential The Utilitarian Benefit of Recycling Loop Potential of Constructions and Building Components Definitions Assessment Parameters and Calculation Methods Prospects

114 114 115 115 115 117

6 Challenges in the Structural Design of Dismantlingand Recycling-Friendly Constructions

118

7 

120 120 124 128

Cost Comparisons of Conventional and Urban Mining Design Constructions Determination of Project Costs A Comparison of Example Constructions Cost Comparisons 1 to 3

Wadden Sea Centre, Ribe (DK) 2017, Dorte Mandrup

41

Detachable Connections and Constructions Petra Riegler-Floors, Annette Hillebrandt

The prerequisite for high-quality recycling is usually the ability to separate building materials cleanly by type. To facilitate this, the building components as well as the individual materials must be connected in a detachable manner. Construction involving detachable connections or joints offers several advantages over the lifetime of a building: • Construction phase: The implementation of a detachable joint can often be more efficient, both temporally and financially, e.g. due to quick assembly that is not subject to inclement weather, or through the elimin­ation of drying times. • Utilisation phase: Necessary maintenance procedures such as the replacement of individual damaged elements or of short-lived building component layers, as well as modernisation efforts for design reasons (due to new users), can be carried out more simply and inexpensively. • Demolition: In the process of dismantling the entire building or individual building components, separation of materials by type allows raw materials to remain in circulation. The reuse of these raw materials has economic advantages, whereas the disposal of building waste generates costs.

B 1.1 Physical action a Interlocking b  Friction locking B 1.2 The strategy of functional separation as a ­prerequisite for disassembling by type, compared for different wall structures (according to Valentin Brenner, Sebastian El Khouli et al.) ST = structure type BC = building component M = material B 1.3 Traditional water drainage principle: joints ­covered by overlapping tiles (“monk and nun”) B 1.4 Overlapping technique is used in thatched roofing as well, here with a detachably connected substructure. B 1.5 Detachable joints as construction principle for a ready-to-disassemble house; Maison démontable 1944, Jean Prouvé

42

This chapter presents a selection of examples of detachable connections and constructions in use. Their organisation – as well as that in the following chapter, “The Recycling Potential of Building Materials” (p. 58ff.) – is based on the order of building components found in DIN 276. The focus lies on alternatives to ­composite constructions that are typically difficult to separate and also on a few little-known mono-­material connection systems that are not detachable in all cases but, by virtue of their mono-material composition, nevertheless pose no obstacle to the sorting by type required for recycling (e.g. in timber construction, Fig. B 1.16, p. 48). Systems that are generally made to be separable (such as in steel construction) are mentioned only for the sake of completeness. Unless otherwise specified, the dismantling of the illustrated connection systems is the reverse of the assembly process. The recycling path of the individual

­ aterials in the various joining approaches m is found in “the Recycling Potential of Building Materials” (p. 58ff.). In addition to the newly developed systems, a few traditional detachable connection technologies are presented that still endure today. ­Many millennia-old construction strategies make sense from the detachability perspective as well, especially in moisture-proofing. Here, the principle of covering gaps (Fig. B 1.3) and roof overhangs minimises moisture stresses on seams and joints and facilitates the use of detachable constructions. Even before the age of bonding, waterproof connections could be achieved by clamps or the utilisation of contact pressure. On the one hand, the current market responds to increasingly high and varied demands with a large array of complex composite materials. On the other, however, recent years have seen the development of a broad spectrum of interesting detachable constructions, admittedly mostly conceived not on the basis of detach­ ability or the associated recyclability factors, but rather for economic reasons (e.g. shorter, weather-independent assembly times), flexibility demands or in response to increased safety requirements (e.g. verifiable impermeability of cellar waterproofing before backfilling). A large fraction of the solutions described have been approved by building inspection author­ ities. Some systems, however, are subject to neither an EN nor a DIN regulation and are therefore non-standard or non-regulated products. Before a non-standard product is installed, the building client must be apprised of the ­situation as a matter of principle. In terms of ­detachability and sortability by type, a strategy of separating individual layers by function has proved to be effective (Fig. B 1.2). A roof ­construction consisting of roofing sheet and ­untreated insulation, for example, is recommended over the use of moisture-­resistant insulating material, which cannot be recycled into a high-grade product because of its resin coating. Connection types

Connections between different functional layers and building materials can be categorised by different characteristics. A common way to

Detachable Connections and Constructions

Normal force Normal force

Hampered movement Hampered movement Prevented movement

Static friction

Prevented movement

Static friction

a

b

group them is according to their physical principles (Fig. B 1.1): • Positive locking: the interlocking of the shapes of at least two connection partners, e.g. rivets, hook-and-loop fasteners, standing seam connections, loosely laid padding (along an edge), plugs, chutes, sash locks (window handles) • Friction locking: connection through the action of a normal force and the resulting static friction, e.g. screws, nails, bolts, pegs, clamps, wedges, loose bearings (through weight) • Material bonding: the cohesion of connection partners by atomic or molecular forces, e.g. through gluing, welding, soldering, adhesion

crowbar, while the connection formed between two joists via a nail plate and the liberal use of a nailgun can be undone only with a great deal of effort, or not at all. Assessment of detachability

A few of the methods that rate the suitability of constructions for closed-loop systems take the detachability of joints into account, with a focus on different aspects of the process. Investigations done at the faculty for Building Construction, Design and Material Studies at the Bergi­ sche Universität Wuppertal, for example, view the economic viability of selective demolition as a combination of the labour involved and the value of the recoverable materials. In this assessment, the difficulty of separation by type is determined using a five-point scale for the physical parameter “work”, ranging from “not very difficult” to “extremely difficult” (see “The Work factor”, p. 116) [1]. The system developed at the Institute for Lightweight Structures and Conceptual Design (ILEK) at the University of Stuttgart, on the other hand, rates the degree to which the joining element is damaged during dismantling. This is also done on a five-point scale, which goes from “detachable with no damage” to “detachable only through damage or destruction”. The rating of the ­connection is integrated into the method for analysing the recyclability of buildings via the

In the case of material bonding, joints are generally non-detachable, whereas for friction and positive locking (with the exception of riveting) they are usually detachable. Sometimes, however, a definitive separation into “detachable” versus “non-detachable” is not possible. The detachability of a joint can also depend on ­factors such as weather exposure (moisture penetration, frost and thermal expansion), the material properties of the connected building components or the number of accessory joining elem­ents. A connection between two unweathered timber boards via a single nail, for example, is relatively easily detached with a Composite insulation system

B 1.1

Facade panel

 Ceramic curtain facade

B 1.4

Support Support structure structure Insulation Insulation Finish Finish

Support Support structure structure

Insulation Insulation Finish Finish

Support Support structure structure Insulation Insulation Finish Finish

Support structure Insulation Finish

Support structure

Insulation Finish

Support structure Insulation Finish

ST ST

ST ST ST

ST

M M M

ST ST ST

BC BC

BC BC

BC BC

BC BC

BC

BC

BC

BC

BC

M

M M M

M M M

M M M

M M M

M M M

ST ST

ST

ST

BC BC

M M

ST ST

ST ST

BC BC

B 1.3

ST BC BC

BC BC BC

BC BC BC

M M

M M

M M

M M

M M

M M

BC M M

BC M M

M M

M M

M M

M

M

M

M

M

M

M

M

M

M

M

B 1.2

B 1.5

43

Overview of joining techniques in accordance with DIN 8580 and DIN 8593 Joining DIN 8593-1

Any process by which two parts are made to cohere through the action of gravity (friction), interlocking, spring forces or a combination of these

Applying Laying Layering

The joining of form-fitted parts by making use of gravity, often in conjunction with interlocking, e.g. roofing tiles

Inlaying Inserting

Joining in which one component is fitted into the form of another component, e.g. the insertion of insulating slabs into a roof construction

Nesting/sliding

Joining in which one component is slid into or over the other, e.g. the sliding in of a connecting bolt

Hanging

Joining by hooking the connecting part of one component over that of the other, where the connection is secured by a tension force (spring force, gravity), e.g. the hanging of a tension spring

Clamping

Joining by pushing the connecting part of one component into that of the other, where the connection is secured by a compression force, e.g. a light bulb in a swan socket or a bayonet socket on a compressed air line

Spring clamping

Joining in which one component is deformed elastically before being inserted into another, whereupon the first component returns to its original form and secures the connection via interlocking, e.g. a deforming spring washer or snap closure

Filling DIN 8593-2

A blanket term for the installation of gaseous, vapourous, liquid, pulpy or pasty substances as well as powdery or granular materials or small chunks of matter in hollow or porous solids

Infilling

The installation of gaseous, vapourous, liquid, or solid matter in hollow objects, e.g. fills, blown-in insulation

Pressing on or moulding DIN 8593-3

Blanket terms for any joining process during which the components and possible connecting elements are primarily elastically deformed and unwanted detachment is prevented by friction locking

Screwing (on or in, connecting with screws or tightening)

Joining through pressing on by means of self-locking threads

Clamping

Joining by pressing together using connecting elements (clamps), in which the joined components are elastically or plastically deformed while the connecting elements remain rigid, e.g. lapped/fixed flange

Clipping

Joining by means of spring-tensioned connecting elements (clips), that press the (usually rigid) components together

Interference fitting

Joining of an inner and an outer component, where the external dimensions of the inner exceed the internal dimensions of the outer: joining through packing, dowelling, contraction (shrink fitting), expansion, e.g. the driving in of an anchor bolt

Nailing Dowelling Driving

Joining by the driving or pressing in of nails (tacks) as connection elements into the material. In this way several components are bonded through compression. In the case of driving, the driven element is itself a component, e.g. driving in a hook

Wedging

The mutual compression of two components with the aid of self-locking, wedge-shaped connecting elements, e.g. the block setting of windows

Tensioning

Friction-locked joining of a crank to a shaft by means of a cone or ring-shaped slotted cotter pins (tensioning elements), in which the necessary axial force is supplied by threads

Deforming DIN 8593-5

A blanket term for the processes in which either the joined components or the connecting elements are locally or even ­ ompletely deformed. The deformation forces can be mechanical, hydraulic, electromagnetic or of some other origin. c The connection is normally secured against unwanted detachments by interlocking.

Joining through the deformation of wire-shaped objects

The braiding of wire to form two- or three-dimensional wire meshes, e.g. steel meshes. The mutual twisting of wires (stranding, splicing, knotting, wire winding, wire braiding to form meshes), e.g. stays

Joining through the deformation of sheet metal, tubing and ­profiles

Joining through centre punching or notching, sheathing, broadening, narrowing, crimping, folding, wrapping, overlapping, e.g. standing seam roofing B 1.6

44

Detachable Connections and Constructions

Original form

Original form

Heat Heat causes return to original form

m Mechanical loading during use

B 1.7

so-called recycling graph “joining matrix” (see “Conclusions and Prospects”, p. 30f. and Fig. 3.14, p. 31) [2]. Joining techniques

Most joining techniques are regulated in DIN 8580 and DIN 8593. In reference to these standards, Fig. B 1.6 gives an overview of detachable connecting techniques such as joining, filling, attaching and inserting as well as some kinds of shaping. The joining techniques listed there are normally designed for long-term use. In the case of constructions that are designed to undergo frequent detaching and reattaching processes, the most suitable solutions are the reversible hook-and-loop ­(Velcro-type) fasteners or connections using magnets. It is important to remember, however, that the joining (adhesive bond) between the building material and the hook-and-loop strip or magnet can itself present an obstacle to sep­ aration by type, since it is usually of the type that is either difficult or impossible to detach. Hook-and-loop fasteners Hook-and-loop fasteners consist of two elem­ ents that form a detachable connection by hooking into one another: a “fuzzy” strip with small loops and a similarly shaped hook strip with tiny little barbed hooks (Fig. B 1.8). Typ­ically, these are made of plastics such as PP, PE or PA, and sometimes of non-flammable materials like fibreglass or PPTA for specialised applications [3]. Since 2009, hook-and-loop fasteners made of perforated, thin chrome-nickel sheet have been available on the market (see p. 52f.) Magnetic connections Natural magnets consist of a rare form of magnetite (iron (II,III) oxide). Nowadays, metallic alloys of iron, nickel and aluminium with admixtures of cobalt, manganese and copper, or ceramic materials (barium or strontium hexaferrite), are used in the manufacture of permanent magnets. Especially strong magnets, such as samarium-cobalt or neodymium-iron-boron magnets, are produced in a sintering process using rare earths. A 3.14 cm3 neodymium magnet, for example, can lift 11 kg [4]. This makes it possible to extend the use of magnets to

include the joining of building materials (e.g. interior cladding, acoustic modules; Fig. B 1.9). Magnetic connections can prove advantageous in cramped installation situations, in which mounting from above is not an option. Mono-material systems Mono-material systems represent a special case: The detachability of a joint becomes ­irrelevant when the fastening element and the connected building components are made of the same material, since in this case no extraneous material hinders the separation by type (see “Mono-Material Construction”, p. 102ff.). Detaching steel beams connected with rivets, for example, would be extremely difficult and necessitate the destruction of the fastener. However, because of its mono-material nature, the entire assembly can be routed to the steel recycling facility. A similar situation is found in timber construction: connections made by wood joinery (without connecting ­elements) or with hardwood fasteners such as dowels or screws need not be separated for recycling (Fig. B 1.10).

B 1.8

Future prospects

In the future, shape memory technology, which has thus far been used mainly in machine building and biomedical applications, could play a role in the field of detachable connections (Fig. B 1.7). Shape memory alloys are materials that can “remember” the original form B 1.6  Joining techniques based on DIN 8580 Manufacturing Processes – Terminology, ­Classification and DIN 8593 Manufacturing ­Processes – Joining B 1.7  Detachable connections of the future: so-called shape memory alloys can “remember” the ori­ ginal form imprinted on them in an annealing process even after they have been deformed. B 1.8  Hook-and-loop fastener: for greater adhesion strength the hook strip or indeed both strips can be implemented as so-called mushroom head strips. B 1.9  Magnetic connections for wall glazing in wet areas B 1.10 Detachability becomes obsolete – connecting ­elements for mono-material construction: Kerbig wood screw, Gebrüder Murr, 2012 a  Wood screw b  Wood dowel

B 1.9

a

b

B 1.10

45

B 1.11

that was imprinted on them in an annealing process even after they have been deformed. The completely reversible shape alteration back to their original form is effected by temperature changes. The most well-known such substance is a nickel-titanium alloy [5]. Foundation: Footings, Cellars Footings, i.e. building components in direct ­contact with the ground, are normally built of a non-detachable composite of concrete, gluedon waterproofing and bonded poly­styrene (PS) perimeter insulation. For every functional layer, however – for waterproofing, insulation and foundation – there exist separable and detach­able alternatives suitable for closed-loop systems. Foundations

Often it is not necessary to use concrete foundations. Furthermore, the installation of detachable and recyclable constructions is a significantly quicker and more flexible process. Ground screw foundations Ground screws made of hot-dip galvanised

B 1.12

46

steel (a special type of stainless steel) serve as individual footing foundations for timber and steel buildings of up to three storeys and for outdoor structures (fences, photovoltaic arrays, etc.; Fig. B 1.12). When overlaid with a support grid they can also function as strip footing (for the distribution of linear loads). They can be used in soil classes I (topsoil) to VII (hardto-fracture rock). They are available in sizes ranging from 50 to 300 cm, with a maximum carrying capacity of 10 tonnes per footing. For soil classes I and II, which are typical for Europe, the useful life span of the screws is 100 years with the appropriate corrosion protection (100 µm thick galvanisation, with a soilend corrosion allowance of 1.5 mm) [6]. The installation is not weather-dependent and takes only a few minutes per footing (Fig. B 1.11). The foundations can support loads immediately, with no earth-moving or concrete construction work required. The ground screws do not create sealed soil surfaces, though they can be used in areas that have already been sealed. The rapid repositioning of screws is unproblematic [7]. Ground screw foundations require an Individual Approval (Zulassung im Einzelfall, or ZIE),

B 1.11 Small and medium-sized ground screw footings are installed using manual means for soil classes up to III (sand, gravel). For larger ground screw foundations and for soil classes through VII, excavator-mounted screw driving machines or a free-standing machine (also usable as a driverless GPS-steered surveying and drilling robot) must be employed. B 1.12 Two-storey timber structure on ground screw foundations: School building, Chur (CH), Projer Holzbauunternehmung B 1.13 Load-bearing and capillary-breaking recycled foam glass insulation beneath ground slabs: a  as a packed gravel bed b  as dry-installed panels B 1.14 Foam glass gravel as vertical perimeter insulation in wall bags used as a sheathing aid (for material recovery by type) B 1.15 Loosely laid three-layer cellar insulation ­system, snugly attached to the building with clamping strips

although a National Technical Approval (allgemeine bauaufsichtliche Zulassung, or abZ) is in the application process. Steel pile foundation For greater loads, driven displacement piles made of steel pipe or standard Å-beams can be used. They are inexpensive and relatively easy to remove, though less suited for densely populated areas because of the concussive shocks caused during their installation. For extended use, protection from corrosion is needed (e.g. by oversizing; see “Protection through oversizing”, p. 68). Perimeter insulation

Closed-cell insulation in ground-contact areas can be achieved in a recycling-friendly manner, for example through the use of foam glass made of expanded (foamed) waste glass. Perimeter insulation under the ground plate Recycled foam glass can be installed under the ground slab in crushed gravel or panel form as compression-proof perimeter insulation. To form the substratum with foam glass gravel after the ground pipe excavation and installation work is completed, the foam glass is deposited, levelled and lightly compacted on a prepared geotextile sheet (see “Insulating foam glass gravel”, p. 90). The gravel layer must extend far enough beyond the edges of the ground slab perimeter to ensure that the ground plate is adequately frost-proofed [8]. Foam glass panels are installed dry on a thin gravel bed to ensure an even surface, and a ground plate of waterproof concrete is placed over it (Fig. B 1.13 b). In this process, care must be taken with pressed and offset joints [9]. The installation of both versions is quick and easy and independent of the weather. Thanks to foam glass’ load-bearing and capillary-breaking characteristics, its use makes strip foundations with double-sided insulation, frost walls as well as blinding layers unnecessary. The material is also drainage-capable and non-flammable, and allows for mono-material reuse at the end of the building’s lifetime. Both systems have both National Technical Approval and European Technical Assessment (ETA) status [10].

Detachable Connections and Constructions

a

Perimeter insulation of the cellar wall In place of bonded, rigid foam perimeter insulation, recycled foam glass can be used as vertical cellar insulation when mounted with the help of textile wall bags (Fig. B 1.14). To install the insulation, the tops of the empty bags are first temporarily attached to the cellar ceiling or walls during construction. The bags, which can be up to 3 m long, are then filled with foam glass gravel. Concurrently, the construction pit is filled and compacted in layers. Beneath the bags, a gravel bed or drainage pipe must be installed to ensure that accumulated water is diverted. It is a good idea to combine this type of vertical insulation with foam glass gravel insulation under the ground slab. In this case the drainage pipe can be integrated into the portions of the foam glass substratum that extend beyond the ground slab. The occasional penetration of moisture into the insulation after heavy rainfall is taken into account in the manufacturer’s stated λ-value. On sloping sites, the uphill side is often furnished with two of the 45-cm-thick bags, one behind the other, in order to forestall damage from hydrostatic pressure [11]. This system can also be installed regardless of weather conditions. The vapour-permeable construction drains readily and is resistent to damage from rodents and other vermin. Foam glass gravel has National Technical Approval [12] and the sheathing support provided by the fabric wall bags requires no add­ itional permits. Cellar sealing

In the creation of a closed-loop-optimised construction, the thick bitumen coating or other types of glued seals commonly used in groundcontact building components can be avoided by employing a loose seal instead, or by building waterproof concrete tanking. Loosely laid cellar sealing system A loosely placed cellar sealing system origin­ ally developed for the construction of petrol stations and waste disposal sites makes it ­possible to test for leaks before the construction pit is backfilled. The system consists of three layers: an outer protective fibre mat, a waterproofing sheet of high-density polyethy­l­

ene (PE-HD) and an inner ventilation layer (composite of a pressure-resistant PE-HD drainage material and polypropylene fleece), which transports water vapour from the interior or moisture from the cellar wall or ground plate to the outside air as well as diverting ­condensate into the inspection shaft. The max­ imum standard height of the sealing system is 2.80 m. It can be used on any wall material that is vapour-permeable. For installation, the protective fleece is laid out on the construction pit floor (level soil with no sharp rocks, no blinding layer necessary), followed by the waterproofing layer. Every seam should be thermally double-welded and the seals tested with compressed air. Finally, the ventilation layer should be positioned. After the ground slab and cellar walls (and, where applicable, the insulation) are in place, the ventilation layer should be drawn up vertically to a point above the splash zone, where it termin­ ates in its final position in open air behind the facade. In the next step, waterproofing sheeting is hung and affixed to the upper edge of the outer cellar wall with a clamping strip (Fig. B 1.15). The edge at which it attaches to the waterproofing ground sheet as well as any seams between adjacent sheets must also be heat-sealed and tested for leaks. After the protective fleece is put in place, the construction pit is backfilled (see “Multilayered plastic cellar sealing”, p. 93) [13]. The advantages of this system, apart from ease of dismantling, are that its impermeability can be verified before construction work continues, and no curing times are required. The basement waterproofing system has been categorised as “state-of-the-art technology” by the German Institute for Building Technology (Deutsches Institut für Bautechnik (DIBt)) as defined by DIN 18 195 [14]. The sealing sheeting is certified in accordance with DIN EN 13 967 [15]. Waterproof concrete tanking with metal waterstop strips When building a concrete cellar, the construction of waterproof concrete tanking completely obviates the need for a waterproofing layer that might contaminate the concrete. To support the

b

B 1.13

B 1.14

B 1.15

47

Wall and ceiling Cross-layering of boards joined with wood dowels for use as a wall and ceiling element

Casing elements with V-shaped support structure to avoid continuous timber sections (thermal bridges); the gaps in between contain pipes and thermal or ­impact sound insulation

Stacked board element of vertical slats joined together with dowels to form a finished component

separability and recyclability of the concrete, it is advisable when selecting sealing for the building component joints to choose metal water-stop strips (preferably made of galvanised or stainless steel) and to avoid the use of epoxy-resin-filled grout hoses.

Wall Multilayered standing block, boards connected by box and dovetail joints

Support Structure Timber panel and steel framed buildings are generally easily detachable structures. Mineralbased solid buildings, on the other hand, have thus far presented very little scope in this regard. A mono-material construction can ­render questions of detachability obsolete (see “Mono-Material Construction”, p. 102ff.). In solid timber construction, wall, ceiling and roof elements are usually screwed together in a readily detachable way.

Vertical profile system of milled, interlocking and dowelconnected squared timbers

Solid timber construction

Solid timber construction has produced a multitude of systems in recent years for walls, ceilings and (pitched) roofs that rely on the geometric interlocking of individual boards or on mono-material hardwood fasteners, without the use of glues or metal connecting elements, and are therefore candidates for high-quality mono-material recycling. The systems are generally windproof and allow for the installation of vapour-permeable walls without sheeting. Appropriate elements in various thicknesses and with an interior insulation layer are also available as soundproofing. From a certain thickness on, a few of these systems also meet special thermal insulation requirements. The interior side is typically available fully ­finished in different wood types and qualities (sufficiency thinking; see “Sufficiency and

Ceiling and roof Stacked board element; version with contoured underside for sound absorption possible

Advanced version of the historical dowel-beam ceiling: milled horizontal beams, connected to one another via full-length mouldings – as a finished component or individu­ally installed on site

Ribbed slab, trickle protection through dove-tailed boards in the slab layer; if used as a ceiling the interstitial gaps are packed with heavy fill for noise protection, if used as a roof they are filled with thermal insulation

Solid wood ceiling and roof element: the traditional wood joining techniques of dovetailing and thread-chasing make possible the trickle-proof joining of solid wood ­profiles

B 1.16

48

B 1.16 Examples of a few mono-material and therefore recyclable systems using various timber construction principles for walls, ceilings and roofs B 1.17 Traditional wood joinery connections, e.g. peg joint, mortise and tenon joint, lap joint B 1.18 Airtight and windproof diagonal reinforcing panel of solid wood boards connected via traditional dovetail joints

Detachable Connections and Constructions

rebound effects”, p. 11), but can also be furnished for a given installation space and with any desired finish. For most systems, mounting slits are milled into the element cross-sections so that they are invisible once the elements are installed. Individual wall and ceiling elements are usually connected with large screws or via screwed-on steel angles. Fig. B 1.16 lists a selection of systems based on various construction principles. Timber-framed and timber panel construction

In timber-framed construction, the joining of individual building components is often achieved with the use of difficult-to-detach nail plates, which are attached on site with a nail gun. Preferable options are screw connections which are more readily detachable, or wood joinery connections without fasteners. Not so much with a view to detachability as to sufficiency thinking, in timber panel construction it is advisable to assemble walls that are progressively more vapour-permeable from the inside outward and that do not employ membranes (vapour barriers, windproofing) at all. Mounted on the inside of the entire cavity-­ insulated timber frame construction is vapourinhibiting oriented strand board (OSB) planking; on the outside, e.g. a windproof MDF panel. The joints of the panel materials must be glued, preferably with adhesive strips that are relatively easy to remove and whose mass is negligible in the overall scheme of things. As a recycling-optimised option, the windproof ­connection between the MDF panels and the timber framework can be achieved with woolfelt-covered kraft paper tape (see “Windproofing made of new wool on kraft paper”, p. 92). Traditional wood joinery connections Thanks to computer-assisted milling technology, the complex traditional method of wood joinery for connecting timber building components without the use of metal fasteners, based on centuries of craftsmanship, has once again become economically viable. Most of the time, due to the expansion of the wood, once joined, the components can no longer be separated, but the mono-material nature of the joining poses no obstacles to the high-quality recyc­

B 1.17

B 1.18

lability of the timber. Depending on the geom­ etry of the joined components, connections are classified as longitudinal, transverse, corner, oblique, and cruciform types [16]. The ­joining techniques include the butt, mortise and tenon, lap, box, neck and notched bevel joints (Fig. B 1.17).

When a secondary structure of timber becomes necessary because of the large spans in steel construction, it can be implemented like timber plank construction without plastic films, with OSB planking on the inside and MDF on the exterior.

Solid wood diagonal panel bracing If bracing is achieved via a panel component (in-plane action) rather than through tension or compression elements, a recommended glue-free alternative to OSB panelling is a solid wood panel composed of planks. The timber sheet shown in Fig. B 1.18 is based on a trad­ itional dovetail joint by which the 30-mm-thick solid single boards are connected to form a panel. The panel is airtight and consequently windproof, since humidity causes the boards to swell slightly and close any gaps. In the assembly of prefabricated components, as for example for timber frame walls, the large finished diagonal panels are connected to one another on-site via clamped-on swelling tape to yield airtight joints. The diagonal arrangement allows the panel to act as reinforcement. The interior side is designed to be the visible face and can therefore be used without additional cladding (see “Solid wood diagonal panels”, p. 80) [17]. The panels have National Technical Approval.

Exterior Coverings: Walls, Pitched Roofs

Steel construction

Since detachable connections are common practice in steel frame construction, they will not be further described here. Joints that are non-detachable, or detachable only through destruction, e.g. welds or rivets, represent mono-material connections and therefore allow for unproblematic high-quality steel recycling. To raise the mass for noise insulation, the slab structure of trapezoidal sheet metal typ­ ical in steel construction can be packed with a fill of sand, for example. The fill simplifies the laying of pipes and is easy to remove and reuse when the building is demolished. Over this, a dry screed construction (see p. 54ff.) is recommended, as it is easier to dismantle and requires no drying time.

In order to facilitate the separation of individual layers of exterior covering – facings, substructures, windproofing and insulation – from one another and from the structural framework during demolition, it is advisable to build a rearventilated construction made up of separate functional layers. Rear-ventilated curtain facades

Rear-ventilated curtain facades are well-suited for exterior walls as well as for pitched roofs and can be built in a large number of easily detachable variations. As the outer shell, various types of panelling, in addition to shingle, cassette and standing-seam sheathing can be used, but other options include taut membranes, meshes or nets. These sheathings can be attached visibly or in concealed fashion via screws or hinges, plug connections or clamps. The substructures can usually be readily dismantled. In order to facilitate the three-dimensional installation of the facade elements on the building site, multi-part metal profiles are generally bolted to structures via slotted holes. If the exterior shell of a pitched roof construction is not proof against driving rain, it is advisable to provide for sub-roof construction on the peak-and-trough principle, which obviates the need for sealing screws or glued attachments. The outer sheathing is screwed either onto a galvanised or powder-coated trapezoidal sheet that is laid in a positive position, overlapping in the flow direction, or onto vertical battens covered with waterproof sheeting. The water flows off in the trough (concave corrugation) while the screw connection is implemented on the crest (convex portion; see Example 01, p. 138). Natural stone facades with concealed attachments can pose a challenge to the detachabil49

B 1.19

ity of rear-ventilated curtain walls. Cemented undercut anchors can be removed undamaged from the natural stone slab only with great difficulty. Since there is a ready market for the ­reuse of natural stone slabs, especially large slabs, detachable connections generate a significant economic advantage during demolition. Mechanical system for the concealed attachment of natural stone facades A mechanical system makes it possible to invisibly attach natural stone slabs as ventilated curtain facades onto a screwed-together aluminium substructure in solid or framework construction (Fig. B 1.19). The backs of the natural stone slabs are provided with slits at the factory, by which they are then hung into special aluminium clips on the substructure. The slabs stay fixed through the spring tension of the clips. They can be installed flush or in varying material thicknesses with few joint measurements required. The slabs are individually exchangeable within the surface, making repairs significantly easier than in interlocking systems, in which the facade must be dis­ assembled in the reverse mounting sequence until the damaged slab is reached. The installation of the system is weather-independent [18]. These systems require individual approval and National Technical Approval status within Germany is currently in the process of being authorised.

B 1.20

hidden corner profiles. Stainless steel clips (connector plates), placed into prefabricated grooves in the bricks, interlink the bricks with one another, while cavity wall dowel pin anchors (4 per m2) attach the back of the wall to the structural framework. At lintels, ­stainless steel brackets should be installed; likewise at every 6 m of height to support ­vertical loads. Only the bottom layer of bricks is set in a mortar bed (levelling layer), and the final upper course is cemented. Avoiding the use of mortar ­eliminates efflorescence, thus reducing maintenance costs [19]. The system falls under National Technical Approval [20]. Windproofing and insulation in ventilated constructions Windproofing in ventilated constructions can be affixed in a detachable manner as a screwed-on MDF panel with sealed joints, for example (see “Timber-framed and timber panel construction”, p. 49), or as stapled sheeting. Even though connections via staples generally do not allow for the completely damage-free removal of the sheeting, in practice they present no obstacles to the separation of building materials. Insulation in mat or panel form can be packed between battens and screwed in place either through additional externally applied battens or via insulation anchors, so that their detachability is ensured. Insulating fills are blown in as cavity insulation.

Rear-ventilated curtain walling

Unventilated facades

A broad market also exists for used solid bricks. In traditionally mortared, rear-ventilated curtain walls, however, the mortar adhesions must first be manually removed from the recovered bricks in a laborious process (see “Ventilated curtain facades on load-bearing exterior wall”, p. 109).

As a rule, unventilated facades tend to be poorly detachable composite constructions. A recent collaboration between Graz University of Technology and a manufacturer has produced a hook-and-loop fastening approach for insulating composite system (ICS) facades. In this approach, plaster is applied seamlessly onto recycled foam glass mounting panels with fibre matting attached to their reverse sides. The loops of this fibre matting form a strong but reversible bond with their mushroom-headed counterpart fastening elements (plastic dowels), which are anchored in the structural framework. The insulation can thus be freely chosen and dismantled, separable by type [21]. The plaster is, of course, non-detachably con-

Mortarless system for brick curtain walling Originally developed as a fast, weather-­ insensitive method for the construction of curtain walls (see “Installation cost”, p. 120), for some time now a dry-stone system has made mortarless bricklaying possible (Fig. B 1.20). In this technique, dry bricks are stacked vertically on top of one another, with their joints ­offset, on 50

nected to the mounting panel, as is the mounting panel to the looped-fibre matting, posing a continuing challenge to the selective dismantling and recyc­ling process. The system is currently undergoing practical testing at construction sites in Germany and Austria [22]. Exterior Floor Coverings: Flat Roofs, Roof Terraces Flat roofs and roof terraces are areas where bonded composite constructions are frequently used. However, through forward-looking building methods and the use of traditional construction techniques, approaches utilising liquid sealants as well as glued roof sheeting can be easily avoided. A number of new developments are also increasing the range of available options. Roof sealing A preferable alternative to a bonded composite of sealant, insulation, vapour barrier and support structure is a mechanical safeguard against wind suction that can be provided by weighting, e.g. with gravel, terrace pavers or a green roof (see “Seals and Separating Layers”, p. 92f.). An inverted roof represents a consistent development extension of this approach, though the insulation material creates a bit of an obstacle if plastic foams are to be avoided. In principle, the use of foam glass panels would be the most recycling-friendly alternative, but the open cells at the cut surface of the panels fill with water, which freezes in winter. This causes the cell walls to burst, allowing the water to access further cells of the foam glass structure. Over time this leads to the formation of micro-fine cracks, which widen and enable water to penetrate further. Repeated freeze-and-thaw cycles eventually cause significant damage to foam glass panels and lead to a corresponding decline in their insulating properties. Since the typical use of foam glass panels (encased front and back in bitumen for sealing and vapour proofing) does not allow for sufficiently strict separ­ation of materials by type and therefore hampers recycling efforts, the construction of a warm roof with loosely laid seal and ballast

Detachable Connections and Constructions

B 1.21

­ utlined in the “Detailed Catalogue” is recomo mended (see Example 02, p. 144ff. and Ex­­ ample 04, p. 152ff.). If wind suction prevention through weighting with ballast is impossible for structural reasons, the sealing sheeting can be friction-locked to the support structure in various ways with the aid of connector elements (Fig. B 1.23) [23]: • Lap seam connection: The connecting elem­ ents, which are placed at regular intervals along the edge of a sheet, are overlapped by the adjacent sheet. The two sheets are then welded together to form a seal. • Linear connection: After the sealing sheeting has been laid and welded, it is fixed in place by rigid metal brackets screwed on at maximum intervals of 5 m. A sealing strip covering the brackets is then welded to the roof seal in order to prevent water penetration via the screw connections. • Field fasteners: Roof pegs are arranged in a grid pattern and installed underneath the sealing layer according to the manufacturer’s instructions, either through the seal (in the style of a sealing screw) or without penetrating the seal. Induction is then used to weld the sealing sheet to the pegs [24]. In a newly developed system, a hook-andloop fastener fixes the sealing ply in place (Fig. B 1.21). In this process, the hook strips are rolled out parallel to one another on the roof surface above the insulation and anchored to the substructure with roofing screws. Then the bitumen polymer sealing membrane, of which the entire underside is coated with a polyester fibre mat, is rolled out and pressed on. Finally, the longitudinal and transverse overlapped edges are sealed with a heat gun [25]. The European Technical Assessment (ETA) for the system is currently still undergoing the approval process [26]. Roof edges

Roof seals can be secured mechanically at the roof margins with roof edge end profiles or covers. Roof edge end profiles consist of multiply crimped sheet metal parts. The time-tested connection via adhesion turns out to be the best

a

b

B 1.22

solution here, both in terms of its impermeability and its demolition-friendliness (Fig. B 1.24). In this approach, the parapet coping is clamped over a retainer element that has been previously screwed onto the roof parapet, thus avoiding a screw penetration from above, which would then need to be sealed. Roof edge end profiles With the use of roof edge end profiles the (plastic or bitumen membrane) roof seal can be pressed on and clamped. This occurs via systems consisting of two or more parts that can accommodate the thermal expansions of the sealing sheet. Typically, the profiles comprise retainers (for mounting on the parapet), face plates and clamping profiles made of extruded aluminium. The multi-part systems also include expansion joint cover plates (Fig. B 1.22 b). Twopart roof edge end profiles are suitable when the visible breadth of the face plate is small (Fig. B 1.22 a). In general, systems with a snapon mechanism are preferable, for example, to those that employ multiply screwed clamping strips. Solutions involving continuous clamping are naturally more secure than those fixed at intervals. Multi-part roof edge end profiles should be used for greater face plate heights. The systems can be mounted regardless of the weather conditions and the sealing membrane can be replaced with little difficulty [27]. Flat roof end profiles are manufactured based on the flat roof guidelines issued by the Central

B 1.19 Easily repaired and dismantled – hidden connections for natural stone slabs B 1.20 Dry-laid bricks as an alternative to mortared ­masonry siding B 1.21 Hook-and-loop fastening system to protect the roof seal from wind suction B 1.22 Easily repaired and dismantled – end profiles for flat roof sealing sheet edges a Two-part system with pre-punched slots and defined drip edge at the profile base b Multi-part system with continuously variable slope adjustment B 1.23 Various options for mechanical wind protection without ballasting B 1.24 The retaining plate element allows for traditional impermeable joints. B 1.25 Lapped/fixed flanges: tight sealing of roof penetrations by clamping

Lap seam fasteners

Linear fasteners Sealing screw principle Induction principle Sealing screw principle Induction principle Sealing screw principle Induction principle

Field fasteners B 1.23 Parapet coping Parapet coping Retaining element Parapet coping Retaining element Retaining element

B 1.24

Lapped flange Lapped flange Lapped flange Fixed flange Fixed flange Fixed flange

B 1.25

51

B 1.26

Association of the German Roofing Trade ­(Zentralverband des Deutschen Dachdeckerhandwerks (ZVDH)) in December of 2016 and on the current state of the art. A CE ­designation in accordance with EU regulation 301/2011 is not necessary [28]. Penetrations of the roof covering Necessary penetrations of the roof covering (e.g. for guard rail posts) can be implemented with a lapped-and-fixed-flange construction in accordance with DIN 18 195-9 (Fig. B 1.25, p. 51). This comprises a two-part construction (usually of weldable steel) for clamping down on a seal, using pressure to create a watertight connection. The top of the lower component, the fixed flange, forms a plane surface with the adjoining roof parts that are to be sealed. The sealing sheet is sandwiched between this surface and the upper (lapped) flange via threaded bolts and nuts.

installations and import little moisture into the construction site. For office use, C2C-certified partition wall systems of glass with steel or aluminium supports, which can be repositioned as needed, are well-suited (see “The materials cycle concept in the ­Cradle-to-Cradle system”, p. 29; Fig. B 1.26). They also offer greater flexibility of use [29].

plane would in principle be desirable, although it is generally economically unfeasible. In solid timber construction, the interior and factory-integrated installations are usually ­produced with an optical finish and do not require cladding. The following examples illustrate two specific detachable connections of interior facings that meet stringent requirements in terms of ­flexibility, durability and thermal stability.

Interior wall facing Metal hook-and-loop fasteners

Similar to the support structure, stud ­partition walls in the interior of the building are easier to construct in a detachable form than solid concrete walls. The wall is built with metal or timber supports onto which drywall, wood composite or loam structural panels are screwed; the insulation is packed between the supports. Stud partitions simplify repairs and subsequent

In mineral-based solid construction, interior walls are generally faced with gypsum plaster. This forms a poorly detachable composite with its substrate and represents a con­ taminant in the high-quality recycling of the mineral-based support structure (see “Mineral materials: masonry materials, concrete”, p. 69f.). Since disposing of the composite as mixed construction waste is very expensive, in practice the plaster is manually removed during demolition – an economically prohibitive task – before the support structure can be broken up by excavators. In framework construction, on the other hand, interior facings on ceilings and walls can usually be readily removed. In general, suspended ceiling grids with an aluminium subframe and facings of plaster, loam structural panels or expanded metal are recommended. As far as the walls are concerned, in the interests of flexibility and ease of repair, a continuous installation

At the Chair of Metal Forming and Casting at the Technical University of Munich, in collaboration with industry partners, two connection systems made from three-dimensional, punched 0.2-mm-thick chrome-nickel metal bands were developed that function on the principle of the hook-and-loop fastener. Both systems consist of one hook strip and one loop or eye strip (Fig. B 1.27). The loop system is based on the established synthetic hook-andloop fastener, in that numerous filigree steel hooks can cling to the rings of the perforated metal loop tape from any angle. The clamping variant is designed for increased stability requirements and consists of broad hook elements that snap into the openings on the perforated strip. They are bent so as to deform elastically in response to light pressure, allowing them to glide into the openings (the concept is similar to that of the plastic quickrelease buckles on rucksack straps). After

a

a

b

Interior Walls

52

b

B 1.27

c

B 1.28

Detachable Connections and Constructions

snapping into place, the hook arms spring back to their original wide-spread shape and, like expanding rivets, exert resistance to pressures in the opposing direction. Depending on the direction of the clinging force, this connection can withstand loads of 7 to 35 N/cm2. The metal bands of both versions are monomaterially attached to the substrate, e.g. by welding or riveting [30]. Aside from the large load capacities of up to 7 tonnes per square metre of hook-and-loop band, their advantage lies in their high resistance to chemical and thermal (up to 800 °C) exposures. They make an almost unlimited detaching and reattaching of two building components possible without the need for tools. The product is neither standardised nor regulated. Magnetic and track fastening systems for glass wall coverings in wet areas As an alternative to cemented tile surfaces, detachably mounted large glass panels are ideal to use as wall coverings in wet areas. In addition, tempered safety glass of 6 – 8 mm thickness allows for various design options, such as backlighting and printing. In a standard track mounting system available on the market, the entire upper and lower edges of the glass are factory-bonded with metal connector profiles that are designed to be mounted onto counterpart elements attached to the wall with screws. The weight of the glass panels themselves and the interlocking shape of the profile fix the panels into position. (Fig. B 1.28). In the magnetic mounting system, magnets are screwed in at positions along the mounting tracks on the wall, while their iron partner elem­ents are glued onto the back of the glass panels at the manufacturing stage. In both systems the glass pane is reversibly attached to the wall (it can be detached with the aid of a suction frame). Silicone is used to seal the joints between panels. After dismantling, both metal and glass are available for reuse. Magnetic mounting elements are also usable for facing materials outside of wet areas. Quite often they are employed, for example, to attach acoustic modules. The product is not standardised or regulated [31].

Floors Conventional floor constructions usually consist of composite elements that are difficult to se­parate: in radiant floor heating, for example, the covering is glued onto mineral heating screed, which is a poorly detachable composite of screed and (plastic) pipes, and which itself is difficult to remove from the impact sound insulation layer underneath. However, for each of the component types – coverings, screeds, radiant floor heating systems – there are several detachable construction alternatives. Here, too, their economic advantages are readily apparent, as they take less time to implement, are easier to replace during renovation and do not require drying times. Some of the systems also weigh less or have a reduced installation height. Floor coverings

Many detachable options exist for floor coverings. Floating parquet flooring with tongueand-groove connections or screwed-on solid wood planks, for example, are well-known constructions. Below is a list of some of the less common solutions. Click-lock linoleum floor panels In its sheet form, the natural building material linoleum requires both a perfectly level substrate – usually only achievable through the use of smoothing cement – and full-surface bond-

B 1.29

ing. Click-lock linoleum floor panels, on the other hand, are less demanding with regard to surface evenness and can be installed on noncementable floors (Fig. B 1.29). In this system, the linoleum is factory-mounted on fibreboard panels, the other side of which is covered with a layer of cork (see “Linoleum”, p. 86ff.). The resulting tiles are laid in a floating installation and interlocked with a specially designed tongue-and-groove connection. In this manner, areas of up to 100 m2 with a maximum edge length of 10 m can be covered seamlessly. Linoleum tiles are suitable for use over radiant floor heating, but not in wet areas [32]. They have received National Technical Approval [33]. Dry installation of ceramic tiling The dry installation of ceramic tiling functions much like the system for linoleum panels. The ceramic tiles are held in place by their own weight. During manufacture, a 2.5-mm-thick

B 1.26  Repositionable glass partitions for office use B 1.27 Metal hook-and-loop fastener strips for very high-strength hook-and-loop applications a  Snap-closure variant b  Hook-and-loop variant B 1.28 System for attaching wall glazing in wet areas a and b  for hanging mounts c  via magnetic fasteners B 1.29 Click-lock linoleum floor panels are laid seamlessly in a floating installation. B 1.30 Ceramic tiles in a floating installation are easy to replace.

B 1.30

53

Carpet

Felt underlay

Tack strip

Wall

Subfloor B 1.31

layer of cork is sintered onto the underside of the tiles, which improves both their impactsound-insulating properties and their adapt­abil­ ity to the substrate. The cork layer protrudes 1.5 mm beyond the tile on all sides. When the tiles are laid they are therefore separated by 3-mm-wide gaps, which are grouted with a specialised dispersion adhesive (Fig. B 1.30). The installation time is relatively short compared to that of cemented tiles and the covering can be walked on after 12 – 24 hours. Individual tiles are reasonably easy to replace by ­cutting the joint, lifting out the tile with a suction frame, installing the new tile and regrouting. The system has National Technical Approval [34]. B 1.32

B 1.33

B 1.34

54

Floating installation of floor-hugging carpet tiles Carpet tiles are especially well suited for installation in spaces with lots of angles. In accordance with DIN EN 1307, for coverings with a surface density > 3.5 kg/m2, an adhesive bond to the substrate is no longer required [35]. This minimum self-weight for positional stability is achieved through a heavy coating in the carpet backing. Along floor edges and at doors, the tiles need to be fixed in place with a doublesided adhesive strip (Fig. B 1.32) or a hookand-loop fastener. For inconvenient layouts, e.g. very long corridors, the same should be done at a few intermediate points as well. Floating installation is not standardised in accordance with DIN 18 365 [36]. In the meantime, carpet tiles containing a high proportion of recycled material, PVC-free backing (e.g. 100 % recyclable polyolefins) and a weight coating of chalk (see “Fossil-based materials: nylon carpet tiles”, p. 86) have become available [37]. Fitted carpets In rooms with a regular layout it is also possible to lay the carpet out on the surface and stretch it out toward the edges (Fig. B 1.31). To do this, the carpet is hooked onto the diagonally projecting nails of a carpet tack strip on one side of the room and stretched toward the tack strip on the opposite wall. The height of the strip must be adjusted to the thickness of the carpet. The tack strips are friction-locked to the subflooring (using screws for wood or anchor bolts for con-

crete). Woven carpets and tufted pile carpets with fabric backing are especially well suited to stretching. For fleece backing, hook-and-loop fasteners may also be used. The use of an underlay of wool, fleece, rubber or a similar material improves the elasticity of the carpet and provides additional sound and thermal insulation. Stretching the carpet has a positive effect on the wear and thus extends the lifetime of the fabric floor covering. Although it is one of the oldest installation techniques, it nevertheless does not conform to the DIN 18 365 standard [38]. Fills

To raise mass and thereby improve noise insulation, the use of fills in framework constructions between the slab and the impact sound insulation is standard practice. Cardboard honeycomb panels with heavy fill Honeycomb panels allow fill material to be installed at a uniform height over the entire ­surface, and they fix the material in place so that it can be walked on with caution during the construction of the next flooring layer without the need for additional smoothing. A simple construction consists of a cardboard honeycomb cell panel (available in heights from 5 to 100 mm) [39] with a greyboard trickle protection sheet underneath (see “Greyboard separating layers or as trickle protection”, p. 92) and a fill material that forms a level surface flush with the tops of the cells, e.g. sand [40]. In another solution, available as a system, ­honeycomb panels of recycled cardboard (with heights of either 30 or 60 mm) and a paper trickle guard lining on the underside are filled with a limestone granulate or perlite fill (Fig. B 1.33) [41]. Both constructions are installed over the whole surface directly on the level bare slab. Channels for pipes can be cut into the honeycomb panel and backfilled. The impact sound insulation and, for example, dry screed are installed on top of the honeycomb / fill layer. During building demolition, the fill can be suctioned away and the cardboard and fill material can both be recycled by type. The system has European Technical Assessment (ETA) status [42].

Detachable Connections and Constructions

B 1.31 From the time before glue: stretching loosely laid carpet by means of a tack strip B 1.32 Floating installation of carpet tiles, mutually connected through spot-fixed detachable adhesive tabs B 1.33 Cardboard honeycomb panel to aid in the installation of heavy fills B 1.34 Dry screed as finished surface: ceramic screed tiles B 1.35 Wood fibre impact-sound insulation as floor slab: underfloor heating with aluminium thermal conduction sheets B 1.36 Pared down to its essentials: dry installation of a radiant floor heating system consisting of copper pipes and overlaid aluminium thermal conduction sheets B 1.37 Floating installation of ceramic or lava moulding plates to accommodate floor heating pipes Dry screeds

The economic advantage of dry screeds over flowing (or wet) screeds lies in the absence of drying times and in their reduced installation height. In addition, during the demolition phase dry screeds can be easily detached and separ­ ated. The usual approach consists of a floating or screwed-on installation of wood composite or gypsum fibreboard panels. Ceramic screed tiles The 20-mm-thick clay tiles are available in two sizes (400/180 mm and 500/250 mm) and several colours, and can be employed as a ceramic finished surface (either glazed or unglazed) or as a substrate for various other coverings (e.g. parquet, cork, carpet, linoleum). They require an even surface; any uneven areas can be levelled out with a ­mineral-based dry fill of expanded clay shale. The impact sound insulation layer or a floor radiant heating system serve as substructure. The ceramic tiles are laid as a floating installation, connected to one another with tongueand-groove joints and additional adhesive (Fig. B 1.34). They are waterproof and therefore suited for use in wet areas. However, as they are not frostproof they should only be used indoors. When the tiles are laid over radiant heating, the manufacturer guarantees that their good thermal conductivity will allow the room to heat up and cool down three times as fast as with the usual wet screed. The ceramic tiling is

B 1.35

fully serviceable after 24 hours and even able to support the installation of solid wood parquet over it [43]. The product is not standardised or regulated (see “Mineral materials: ceramic tiles”, p. 84).

ommends first installing a gypsum plasterboard or ceramic tile dry screed over the system [44]. The basic element is manufactured in compliance with DIN EN 13 171 and DIN 4108-10 [45], and the heating pipe is certified by SKZ and DVGW [46].

Underfloor heating (UFH) systems

Through the use of connection methods such as screws, interlocks or plugs, the individual components of the underfloor heating systems described below can be easily detached from one another and separated by type during demolition. Thanks to their low installation heights and weights they are also suitable for use in building refurbishments. Installation is simple and does not take much time. UFH: softwood fibre support elements The underfloor heating system consists of 30-mm-thick softwood fibre support elements with pre-milled grooves. Heating pipes composed of raised-temperature polyethylene ­(PE-RT) and aluminium, as well as aluminium heat conduction sheets, are laid into the grooves (Fig. B 1.35). The latter ensure a quick reaction time and even heat distribution throughout the floor surface. To support a solid timber plank floor covering, floor battens should be placed between the wood fibre panels, to which the timber boards can then be attached with screws. For other types of floor covering, the manufacturer rec-

B 1.36

UFH: copper pipes and aluminium heat-conducting sheet In another UFH system, copper heating pipes are mounted on timber beams into which notches have been cut on-site (Fig. B 1.36). Insulation (in the form of fill, mats or panels) is packed between these beams so that a 30-mm space remains for the heating system between the insulation and the top edge of the beam. After the pipes are laid, conducting sheets made of 99.5 % pure aluminium are placed on top of them and snapped into place. The floor boards are then screwed onto the support beams [47]. This system does not require National Technical Approval since it essentially consists of the regulated building products copper piping (bar stock) and aluminium sheet [48]. UFH: ceramic or lava plate Yet another UFH system consists of 45-mmthick plates with countersunk grooves to accommodate the aluminium alloy heating pipes. The plates are made of ceramic or lava (depending on availability: regional production). They are laid on the impact sound or ­thermal insulation layer and connected with

B 1.37

55

B 1.38

one another via a tongue-and-groove system (Fig. B 1.37, p. 55). Coverings such as floating parquet can be installed directly on the plates; mouldings placed between the plates as ­support timbers are intended to be used for screw-connected coverings [49]. The product is not standardised but has been expertly verified in Germany [50]; in Austria it has been issued a certification that conforms to the factory production control DIN EN 1520 [51]. Windows and Exterior Doors, Post-andBeam Constructions

Sealing between frame and structure

The spaces between the frames and the support structure can be packed with rock wool or sealed with a caulking strip (made of hemp, for example). A further option is the use of EPDM foil connecting sheets (see “Fossil-based ma­ terials: PU and EPDM”, p. 95f.). Although these are often glued on, their strip-like shape makes them relatively easy to detach, and their mass is negligible in terms of recycling. A completely recyclable alternative, though slightly more difficult to implement, is to attach the foil connecting sheets to the structure with clamping strips. Windows and doors

For punched windows and entry doors, detachable installations via screwed-on metal window brackets or angles or by block setting with timber wedges are recommended. Post-and-beam facades are generally frictionlocked to the building by multi-part metal angle constructions, which are readily detachable. Systems involving timber support beams are occasionally fixed in place via two conical wooden wedges.

A few manufacturers have now made timberaluminium and metal windows available that are easily dismantled and facilitate the separ­ ation of glazing, sealing elements and structure from one another. With the plug or screw connections most commonly employed, recycling rates of over 90 % can be achieved [52]. A few steel windows consist of 100 % recyclable steel and have slender cross-sections, despite the lack of glued plastic insulation (Fig. B 1.39) [53]. An increasing number of certified products is becoming available on the market (see “Frame and profile materials”, p. 96) [54]. Post-and-beam constructions are themselves generally easily dismantled, as are traditionally assembled systems with plug or screw fasteners and correspondingly shaped profiles (Fig. B 1.40) [55]. A novel structural glazing system

B 1.39

B 1.40

Windows and exterior doors are often secured and simultaneously sealed with polyurethane foam. However, if the functions are separated from each other and the design is correctly planned, the connections are usually readily detachable (Fig. B 1.2, p. 43). Building mounts

56

is predicated on a timber structure, which reduces the carbon footprint by about 40 % as compared with aluminium constructions (Fig. B 1.41). The flush installation of the smooth ­timber-glass-composite element is achieved through a prefabricated, screwmounted substructure with offset, interlocking timber mouldings. The joints are filled with a polyethylene cord and then sealed. Individual elements can be replaced without difficulty [56]. The system is Technically Approved [57]. Sun and break-in protection Fabric sun protection is often made of poorly recyclable composite materials. Most available roller blinds also consist of hard-to-separate composite materials; for example, foamed-­ aluminium sheet shutters [58] in built-in expanded clay shutter housings [59]. Sliding, hinged, folding timber, metal shutters or metal fins attached with screws, or plug-in connectors represent easily disassembled alternatives (Fig. B 1.38).

B 1.38 Folding tombac shutters, Fünf Höfe shopping ­arcade, Munich (DE) 2003, Herzog & de Meuron B 1.39  Steel profile without plastic foam insulation B 1.40 Post-and-beam construction: plug-in and screw connections with support structure and cover strip of renewable bamboo B 1.41 CO2 reduction by 40 %: structural glazing facade with a timber support structure

B 1.41

Detachable Connections and Constructions

Notes:   [1] Rosen, Anja: Entwicklung einer Systematik zur quantitativen Bewertung des Kreislaufpotenzials von Baukonstruktionen in der Neubauplanung. Bergische Universität Wuppertal (doctoral thesis in progress)   [2] Schwede, Dirk; Störl, Elke: Methode zur Analyse der Rezyklierbarkeit von Baukonstruktionen. In: Bautechnik 94 (2017), H. 1, p. 1– 9  [3] https://de.wikipedia.org/wiki/Klettverschluss. ­Retrieved on 26.01.2018  [4] https://www.supermagnete.de/faq/Soll-ich-einenNeodym-Magneten-oder-einen-Ferrit-Magnetenkaufen#haftkraft-pro-volumen, as of 02.02.2018 https://de.wikipedia.org/wiki/Spin, https://de.wikipedia.org/wiki/Magnet, https://de.wikipedia.org/wiki/ Elektromagnet, https://de.wikipedia.org/wiki/Magnetit, https://de.wikipedia.org/wiki/Spule_(Elektrotechnik). Retrieved on 26.01.2018   [5] Langbein, Sven; Czechowicz, Alexander: Konstruktionspraxis Formgedächtnistechnik: Potentiale – ­Auslegung – Beispiele. Wiesbaden 2013 http://www.fg-innovation.de/fg-innovation/dokumente/FGL_Kurzinfo_FGT.pdf, retrieved on 16.02.2018   [6] Gutachten Korrosionsschutz der Krinner Schraubfundamente, Korrosion und Korrosionsschutz im Bauwesen. Retrieved on 07.07.2016  [7] http://www.schraubfundamente.de/index.php?eID= tx_nawsecuredl&u=0&file=fileadmin/user_upload/ secure_downloads/ansichtspdf/Broschuere_Sortimentsuebersicht_ohne_Logos_DE.pdf&t=15170640 86&hash=e59de66a3d3e30dc290fa2d44460e10f39 beb333. Retrieved on 26.01.2018 www.ecodesign.at. Retrieved on 27.01.2017   [8] Zegowitz, Andreas; Fraunhofer-IBP: Schaumglas­ schotter als Wärmedämmung. https://www.ibp. fraunhofer.de/content/dam/ibp/en/documents/ Schaumglasschotter-Zegowitztcm1021-97648.pdf. Retrieved on 26.01.2018 https://www.baunetzwissen.de/daemmstoffe/fachwissen/boden-decke/bodenplatte-auf-schaumglas­ schotter-1533407. Retrieved on 26.01.2018  [9] https://de.foamglas.com/de-de/anwendungen/erdberuhrte-dammsysteme/bodendammung/111-bodendammung-lastabtragend-auf-magerbeton-odersplittplanie. Retrieved on 17.01.2018 [10] National Technical Approval (allgemeine bauauf­ sichtliche Zulassung) No. Z-23.34-1579 Foam glass gravel and chipped fill “Geocell” (valid through 05/2020) Z-23.34-1059 Schaumglasplatten Foamglas (until 02/2020) ETA status 17/0903, 22.11.2017 [11] http://www.misapor.ch/DE/Schaumglas/Anwendungen/Perimeter-vertikal.html. Retrieved on 17.01.2018 [12] National Technical Approval No. Z-23.34-1390 Foam glass gravel fill Misapor (until 11/2020) [13] http://www.abg.eu/kellerabdichtung#varianten. ­Retrieved on 17.01.2018 [14] Licensing office, DIBt Deutsches Institut für Bau­ technik, Berlin [15] According to manufacturer: ABG GmbH, Hamburg, 04.04.2017 and 08.02.2018 [16] http://oeffentlichkeitsarbeit.zimmerer-bayern.de/ files/oeffentlichkeitsarbeit.zimmerer-bayern.de/ downloads/presseinformationen/fm-holzbau/Holzverbindungen.pdf. Retrieved on 18.04.2018 [17] http://www.massivholz-junker.de/index.php?article_ id=169 and http://www.massivholz-junker.de/index. php?article_id=165 and http://www.massivholz-junker.de/index.php?article_ id=168, gfm_technisches_datenblatt_16.2.pdf, http://www.massivholz-junker.de/index.php?article_ id=8. Retrieved on 01.05.2017

[18]  www.linea-cladding.com. Retrieved on 19.01.2018 [19] http://www.kdb.de/media/files/clickbrickpraesentation-1.pdf. Retrieved on 19.1.2018 [20] National Technical Approval No. Z-17.1-933, 2 April 2007 “Zweischalige Außenwände mit Verblendschalen aus trockengestapelten Ziegeln mit besonderem Befestigungssystem 90 mm Schalentiefe – 20 m über Geländehöhe – Abfangungen nach 6 m, auf Grundlage der DIN 1053” [21] http://www.sto.de/de/topnav/presse/pressemeldungen_163968.html. Retrieved on 18.01.2018 [22] https://www.sto.de/de/unternehmen/innovationen/ stosystain_r/StoSystain_R.html. Retrieved on 21.03.2018 [23] https://www.baunetzwissen.de/flachdach/fachwissen/windlast/windsogsicherung-durch-mechanische-befestigung-222332. Retrieved on 25.01.2018 [24] https://sfsintec.biz/de/web/industry_solutions/construction/flat_roof/flat_roofing.html. Retrieved on 25.01.2018 [25] http://www.kebu.de/assets/content/files/Dokumente/Flachdach/de/Orig_kebu/Easyklett_01_2016. pdf. Retrieved on 24.1.2018 [26] According to manufacturer: Kebulin-Gesellschaft, Kettler GmbH & Co. KG, Herten-Westerholt, 09.03.2018 [27] http://www.briel.de/produkte/dachabschluss-2/ flachdachabschlussprofil-galant-zweiteilig.html http://www.briel.de/produkte/dachabschluss-2/ flachdachabschluss-system-ventox-mehrteilig-2. html. Retrieved on 01.03.2017 https://www.baunetzwissen.de/flachdach/ fachwissen/ab--anschluesse/dachrandabschluesseunterscheidung-und-vorschriften-156139. Retrieved on 01.03.2017 [28] According to manufacturer: DTB Dachtechnik Briel GmbH & Co. KG, Kelbra, 08.03.2018 [29] http://trennwaende-hamburg.de/index.php/trennwandsysteme/frontpage/panorama-glastrennwandhttp://trennwaende-hamburg.de/index.php/ trennwandsysteme/frontpage/panorama-glastrennwand and http://trennwaende-hamburg.de/index. php/cradle-to-cradle. Retrieved on 15.02.2018 http://www.straehle.de/de/produkte/trennwand­ systeme/system-2000-glaswand/. Retrieved on 15.02.2018 [30] https://portal.mytum.de/pressestelle/pressemitteilungen/news_article.2009-09-02.2452535930. Retrieved on 25.01.2018 http://www.metaklett.de/technologie.html. Retrieved on 25.01.2018 [31] Individual wall design systems, see http://www.sprinz.eu/index.php?Download-Badwelt. Retrieved on 25.01.2018 [32] Installation instructions, https://www.forbo.com/ flooring/de-de/produkte/linoleum/marmoleum-click/ marmoleum-click/bz9e4r#panel_105. Retrieved on 25.01.2018 [33] National Technical Approval No. Z-156.610-1421 Floor panels in accordance with DIN EN 14 041, Marmoleum Click (until 08/2019) [34] https://www.trison-drytile.de/wp-content/uploads/2017/09/Dry_Tile_Broschuere_D.pdf. ­Retrieved on 25.1.2018 National Technical Approval No. Z-156.610-1373 [35] DIN EN 1307 Textile floor coverings – classification, Appendix A.1 [36] https://www.baunetzwissen.de/glossar/t/teppichfliesen-49709. Retrieved on 26.01.2018 https://www.baunetzwissen.de/boden/fachwissen/ textile-bodenbelaege/verlegung-von-textilenbelaegen-151668. Retrieved on 26.01.2018

[37] http://www.desso.de/c2c-corporate-responsibility/ kreislaufwirtschaft/. Retrieved on 26.01.2018, (according to the manufacturer: Tarkett Deutschland, 08.03.2018) [38] https://www.baunetzwissen.de/boden/fachwissen/ textile-bodenbelaege/verlegung-von-textilen-belaegen-151668. Retrieved on 26.01.2018 [39] http://www.swap-sachsen.de/wp-content/uploads/2013/10/K1_AZ_03_Spezifikation.SWAP_. Sinus_.Wabenplatte.unkaschiert.pdf. Retrieved on 16.11.2017 [40] Rongen, Ludwig; Hestermann, Ulf: Frick / Knöll ­Baukonstruktionslehre 1. 35th ed., Wiesbaden / ­Heidelberg 2010, p. 417 [41] https://www.ausbau-schlau.de/wabensystem_ waermedaemmschuettung_1448.php and http:// www.fermacell.de/de/docs/FERMACELL_WabenDaemmsystem.pdf. Retrieved on 16.11.2017 [42]  ETA 03/0006 Fermacell (06/2013) [43] https://www.creaton.de/fileadmin/user_upload/ 09_DOWNLOAD/Produkte/Boden/Prospekt_ Estrichziegel.pdf. Retrieved on 25.01.2018 [44] https://www.thermisto.com/de/systeme/öko/technische-details.html [45]  Data sheet ÖKO Heizelement VA 125 NEU [46] Data sheet Mehrschichtverbundrohr: SKZ A 462 und DVGW DW-BU0016 (not for dim. 14 ≈ 2) SKZ (Kunststoffzentrum, Würzburg), DVGW ­(Deut­scher Verein des Gas- und Wasserfachs, Bonn) [47] http://www.janssen-fussbodenheizung.de/images/ stories/download/Montageablauf-Trockenaufbau. pdf and http://www.janssen-fussbodenheizung.de/ images/stories/download/2-D-Trockenaufbauunbeheizt.pdf. Retrieved on 25.01.2018 [48] According to the manufacturer: Janßen-Heizungs­ Systeme, Xanten. 05.03.2018 [49] www.lithotherm-system.de/pdf/Montageanleitung08-2013.pdf und http://www.lithotherm-system.de/ pdf/Lithotherm-Deutsch.pdf. Retrieved on 25.01.2018 [50] Materialprüfungs- und Versuchsanstalt Neuwied GmbH, Testing report 2-59/0873/17 Untersuchungen an Trockenestrichelementen (09/2017) [51] Boden- und Baustoffprüfstelle GmbH, AT-Leonding, Zertifikat über die Konformität der werkseigenen Produktionskontrolle 1661-CPR-0099 Oö. (03/2014) [52] http://velfac.de/global-de/csr/. Retrieved on 26.01.2018 [53] http://www.forster-profile.ch/fileadmin/media/ forster-profile/documents/umwelt_deklarationen/ epd_forster_stahlfenster.pdf and http://www.forsterprofile.ch/at-de/profilsysteme-in-stahl-und-edelstahlfuer-waermedaemmung-und-sicherheitsanwendungen/forster-unico-1.html. Retrieved on 26.01.2018 [54] https://www.schueco.com/web2/de/architekten/ produkte/fenster/aluminium/schueco_aws_75_si_ plus/. Retrieved on 26.01.2018 [55] https://www.stabalux.com/de/pfosten-riegel-fassade-holz-alu/stabalux-h/. Retrieved on 26.01.2018 [56] http://www.uniglas-facade.de/. Retrieved on 26.01.2018 [57] Uniglas-Facade Z 70-1.226 (until 03/2021) www.uniglas.de/tl_files/content/download/ Broschueren/DE/UNIGLAS_FACADE_DE.pdf. Retrieved on 03.03.2018 [58] https://www.baunetzwissen.de/sonnenschutz/ fachwissen/rolllaeden/rollpanzer-166446. Retrieved on 15.02.2018 [59] https://www.baunetzwissen.de/sonnenschutz/ fachwissen/rolllaeden/einbaurollladen-166454. ­Retrieved on 15.02.2018

57

The Recycling Potential of Building Materials Annette Hillebrandt, Johanna-Katharina Seggewies

Conserving Resources and Avoiding Waste Two hundred and fifty years ago, the impact of humanity’s construction activities on the environment was slight. At that time, buildings were built on a modest scale compared with today. Buildings were costly and complex to construct and lasted several generations. Building represented a major investment of time and money, so buildings, as a whole or in parts, were highly valued. When buildings no longer met the demands made on them, sections of them were often reused in new structures. When there was no further use for a building, its useful parts were reused and the rest decayed. There were no disposal problems. The materials used were, with few exceptions, natural materials that rotted or humified right on-site or nearby land that would be built on again. Construction activity has now grown exponentially due to massive increases in population. In urban areas, the pressure imposed by land prices is shortening the “lifespan” of buildings and making increasingly high levels of land ­utilisation necessary. Building replacement cycles are also becoming shorter because of faster rising demands on buildings’ perform­ ance, especially in industrialised countries. The result is overfilled landfill sites and escalating disposal costs. The construction materials industry develops products designed to meet the various demands of what is now a high-tech building ­industry and optimises them to accommodate the warranty periods the industry grants. It has become clear that parts of the construction products industry try to use every material for any purpose, whether suitable or not, as long as the basic material is cheap enough. This causes problems in disposing of hazardous waste from building materials that can ­endanger health yet have been used unquestioningly for decades (e.g. asbestos). Tests of materials’ suitability trialed over cen­ turies and the optimising of workmanship in construction are now history. Today, so-called product innovations are conquering the market. The range of construction materials in use has 58

greatly expanded in recent decades. Planners are now confronted with an incalculable variety of industrial products whose material compos­ ition hardly anyone can keep track of, let alone assess their end-of-life scenarios. The product responsibility and liability prescribed in the German Waste Management Act (Kreislaufwirtschaftsgesetz – KrWG) has had no effect so far. Society is not protected from the imposition of collective responsibility for the environmental impacts and disposal costs of products (see “The EU Waste Framework Directive and German Waste Management Act”, p. 16). Consumers currently bear all the costs resulting from a product’s disposal at the end of its life, without exception (see “Cost Comparisons of Conventional and Urban Mining Design Constructions”, p. 120ff.). Considered from a purely materials level, every building consists of recyclable or waste materials for which the building’s owner bears the responsibility at the end of their use. The question of whether salvaged materials can subsequently be resold or have to be expensively disposed of must be resolved during planning. A large proportion of the value of a building will only be maintained, regardless of its location, when it has been built out of mate­ rials that can be recycled to make products of the same quality. Groups of materials – their origins, natural cycles of renewal and availability

We have divided the materials used in construction into the following four groups based on their origins and availability: biotic, fossilbased, mineral and metallic. Biotic materials Biotic materials are those resulting from plant or animal growth that rot at the end of their lives and can be returned to the growth cycle as nutrients. They regenerate over periods shorter than or comparable with the “lifespans” of buildings. Because these renewable mate­r­ ials (e.g. wood) are theoretically endlessly available, their use in construction is generally regarded as advisable, as long as they are readily available.

The Recycling Potential of Building Materials

Fossil-based materials The renewal cycles of fossil-based materials, which are also produced based on biological processes, are far longer than any time scale relevant to human usage and construction (e.g. crude oil-based plastic). The natural ­availability of these materials is finite. Technical reprocessing can give fossil-based materials a further “material life”, although the potential for any subsequent use that this can achieve varies greatly. Mineral materials Mineral materials (e.g. natural stone) are cre­ ated by abiotic, natural processes and humify at the end of their lives. Their natural origins notwithstanding, their very long genesis means that these materials’ availability – given appropriate periods for renewal and the human time scale – is finite. Their availability is further ­limited by the very restricted opportunities for recyc­ling these materials.

f­ossil-based materials to generate energy) and “disposal”, are not sustainable solutions for the purposes of conserving resources and avoiding waste. Figure B 2.1 shows the possible usage and life cycles of building materials.

lands and Austria [2] (see Project Example 17, p. 208f.). A product that is used again for its original ­purpose is said to be reused. Oven-fired bricks, for example, can be reused as building material after recovery and cleaning. Durable construction products may be suitable for reuse in another building after recovery ­during demolition, although the possibilities for this are unfortunately limited. The quality of the used product, its resilience in the face of cycles of technical renewal and a lack of acceptance among many users all have an inhibitory effect on recycling. Reusing compo-

Reuse and further use Reuse and further use strategies seek to ­reuse a product while retaining its form. In Europe, in recent years a number of small companies have been established that trade in used structural components for this purpose, e.g. Bau­ teilbörse and Restado in Germany, Salza in ­Switzerland and Harvest Map in the Nether-

Outside of the construction sphere

Inside the construction sphere

Downcycling

Metallic materials Like mineral materials, metallic materials (e.g. copper) are created by long-term natural processes and also humify at the end of their lives. Their natural availability is limited, although the potential for recycling them to make products of the same quality is almost unlimited.

Processing

Recycling

Avoiding waste and recycling

Four strategies for conserving resources and avoiding waste can be pursued to achieve a real circular economy. They are listed below in accordance with their potential impact in the following order: •  Avoidance of waste • Reuse • Recycling • Further use and downcycling to a limited extent [1] The other means of disposal specified in the EU Waste Framework Directive 2008/98/EG, “other recovery” (e.g. direct incineration of

B 2.1  Usage and life cycles of construction materials

Composting

Energetic reclamation

Reuse

Dismantling

Disposal No further utilisation

Maintenance of quality Reuse with retention of product form Recycling, downcycling with break-up of product form

Maintenance of quality biotic loop Small loss in quality Substantial loss in quality Complete loss of quality

B 2.1

59

nents also requires a reversal of the planning process (see “Circularity in Architecture – Urban Mining Design”, p. 10ff.). If an old structural element or construction product can be used again, but not for its ori­ ginal purpose, it is said to be suitable for ­further use. This can be the case when the quality required for its original purpose can no longer be ensured. One example of further use would be the use of old facade bricks as paving in a garden path. The decline in quality means that this kind of further use must be regarded as a loss of resources, making it a form of downcycling. Recycling and downcycling Recycling processes break up a product’s form. Recycled materials become the new basic substance for producing materials of the same quality in an almost closed cycle. Used material is fed into a process from which a new product of the same quality as the ­original product can be made. One example of this is the melting down of a steel beam to make a new steel beam with another kind of profile without losing any of the quality of the recycled material. If a material can only come out of a recycling process with a loss of quality, it is said to be downcycled. One example of this is the making of new profiled glazing from a float glass pane.

Only a lower-quality new product can result from this kind of ‘downstream’ utilisation. Such cascade utilisation can be regarded as fundamentally positive only in the case of renewable raw materials. In general, it involves a loss of resources and generates waste, making it a form of downcycling. Recycling cycles and varietal purity

In describing material recycling below, we ­distinguish between a biotic and a technical recycling cycle (Fig. B 2.2). In a technical ­recycling cycle, used materials are subjected to technical-industrial processing after dis­ mantling and sorting. The cycle is regarded as closed when the secondary raw material it produces has the same quality as the primary raw material and the process results in only an insignificant loss of mass. Every form of recycling in a technical recycling cycle consumes energy. Therefore, if resources are to be conserved sustainably, the focus must be on reducing the overall use of materials – on avoiding waste. In contrast, a biotic recycling cycle involves the rotting of usually biotic (or more rarely ­mineral) materials in composting facilities. The materials cycle that can be used for this type of recycling can be seen as closed as long as some parameters described in the following chapter are met. For both a biotic and a technical recycling cycle, varietal purity is the

Production

Production

Building material

Plants

Technological raw materials Technological loop

Biotic loop

Biological nutrients

Architecture Breakdown Composting

Building material

Architecture

Processing Breakdown Dismantling

B 2.2

60

precondition for recycling materials that can be made into products of the same quality. ­Impurities that impede recycling are usually substances that have been added to the main material to improve the product’s performance (e. g. flame retardants and anti-rot agents). Glued layers, the incomplete separation of which impairs the varietal purity of the main material, also impede the recycling of materials to make products of the same quality (e.g. glued layers of materials from different groups of substances). The same is true of coatings, for example, if they do not belong to the same materials group as the main material (e.g. ­plastic paints on wood). The recycling potential of biotic materials

Using biotic materials is in keeping with the spirit of conserving resources and avoiding waste. The untreated biotic materials cycle is per se closed in nature. People can use the material in construction, but are just “borrowing” it from the natural cycle. There is, however, a risk that cultivating certain plants or ­animals that are seen as a especially useful or profitable will displace other species from their habitats. This will result in a decline in biodiversity (extinction of entire species), damage to ecosystems and global shifts in nutrients reserves. One prominent example of this kind of undesirable development is palm oil monoculture on ­former rain forest land. The cycle of materials produced by cultivating plants or animal ­husbandry is only closed when the materials are cultivated sustainably, so it must be ensured that resources are “harvested” in a controlled manner and that raw materials get the time they need to regenerate and regrow (see “Biotic materials: wood and wood-based ­materials”, p. 65ff.). Biotic materials created as by-products of ­production processes are only used in a closed cycle when the original production process itself was sustainable (e.g. New sheep’s wool insulating felt, see p. 89f.). Even for material that may seem like an insignificant by-product for B 2.2 Biotic and technical recycling cycles, following the Cradle-to-Cradle strategy of Braungart and McDonough

The Recycling Potential of Building Materials

nature, the biotic cycle is not per se regarded as closed (e.g. sea grass insulation, see p. 89). Use of these materials requires extensive research to prevent the possibility of the biotic processes of an ecosystem that has evolved successfully and grown over millions of years from being destroyed by reckless mass harvesting. At the end of their useful “lives”, biotic materials can be returned to the biotic recycling cycle to rot in composting facilities. Plant materials rich in lignin and cellulose are especially suit­ able for creating quality compost [3]. This is a process regulated by the German Biowaste Ordinance (Bioabfallverordnung – BioAbfV). It applies to producers and owners of organic wastes or mixed wastes, so potentially also to property owners [4], but it does not yet offer any information on how to deal with larger ­quantities of compostable waste that will result from construction in future. Here there is a need for political regulation before the still very small organic flows of waste coming from ­construction increase greatly as a result of the dismantling of sustainable buildings. Biotic materials with a high proportion of wood that take longer to compost and have a high heating value currently usually end up being used in energy generation. Wood and woodbased products are currently classified as ­construction and demolition waste at the end of their “lives”. The German Commercial Waste Ordinance (Gewerbeabfallverordnung) regulates their disposal (see “Recycling and reusing wood as material – waste and recovered wood”, p. 65). It makes perfect sense to subject this wood and these wood-based products to cascaded utilisation over several stages after their first use, i.e. to enable repeated recycling of the wood as a material in construction before using it in energy generation at the end of its “life”. This will give sustainably cultivated biotic materials a new material “life” equivalent to that of the original material, even beyond the inherently closed materials cycle. Efforts should be made to promote the continued use of biotic materials that have not been sustainably grown (where the cycle is not closed) in a continuing “product life”. Whole structural components made of biotic construction materials are generally rarely reused or further used and their market share

will remain small in future. Only structural ­elements of historical value or those to which the patina of ageing has lent an interesting appearance are commonly reused in a new way that maintains their quality (e.g. old oak beams or floorboards). The recycling potential of metallic materials

Metallic materials are found in nature in metallic ores. Extracting them from mineral deposits ­involves the destruction of soil structures that have developed over millennia. The result is vast slag heaps with an ore content of around 5 %. The time they take to naturally regenerate greatly exceeds the useful “life” of a building. Very little ore for metal production is mined in Germany, so the country relies almost entirely on imports. Imports of metals from countries ­regarded as politically and economically un­ stable, in particular imports of aluminium, copper, steel and zinc, have been criticised [5]. Producing ferrous and in particular nonferrous metals consumes high amounts of water, land and non-renewable energy and pollutes the environmental resources of water, soil and air. Substantial negative environmental impacts along the entire value chain are the result of the production of these primary raw materials. This all makes the almost perfectly functioning recycling of metals from the urban “mine” very important because, with high rates of recovery, they can be recycled almost infinitely. The recycling of metals can also greatly reduce the energy consumed in their production. In the case of aluminium, recycling reduces its energy ­consumption by 95 % compared with primary aluminium production. The recycling of copper reduces the energy consumed in its production by around 85 % as well as saving more than one third of the CO2 emitted [6]. One particular advantage of recycling metals is that they can be melted down and refined almost infinitely without any major loss of ­quality [7]. In Germany, most metals, i.e. over 80 %, are recyc­led using a highly specialised process [8]. To avoid downcycling, metal scrap needs to be meticulously sorted. Recovering pure metals from metal alloys entails considerable effort and expense in separating the materials.

Alloys can be identified by means of X-ray ­fluorescence analysis. Recent developments enable a precise spectral analysis of the chemical composition of steels, which means material can be sorted for recycling to obtain the actual alloy required for a certain steel melt [9]. The production of nonferrous metals generates wastes such as slag, dross, slurry and ­filter dust, which must be sorted if they are to be recyc­led [10]. Since the value of metal is high, the effort and expense involved is generally worthwhile. Metal retains and even increases its value, which gives it a significant recycling advantage over other materials. The ease with which it can be recycled makes direct reuse of metal structural components the exception rather than the rule. The recycling potential of fossil-based materials

Oil-based plastics and bitumen are the mater­ ials of fossil origin most widely used in construction. Plastics can be extremely durable, they are practically inert and persist in the ­environment for up to 450 years [11]. These materials do not decay on a time scale relevant to us, although their performance as construction materials quickly declines. Few plastics achieve the 50-year service life that construction requires [12], yet in Germany more than 22 % of all plastics produced are used in construction [13]. The potential for reusing plastics and bitumen can vary greatly. Generally, only plastics in the thermoplastics group are recyclable [14]. Only incineration is possible for less valuable plastic mixtures, even though some do not even have high heating value. Higher quality plastics can undergo several recycling processes to make products of the same quality before being finally used in energy generation. In Germany, the proportion of recycled mater­ ials in products used in construction is currently around 38 % on average [15]. The varietal purity of plastics and recovery of used plastics without layers of other materials adhering to them is crucial to their recycling potential. Used in sealing sheeting and in semi-finished products, profiles or prefabricated components, polyvinylchloride (PVC) is an inexpen61

sive material that plays by far the greatest role in construction [16]. Although there are feebased recycling systems for PVC products, their use should generally be reconsidered. A study commissioned by the German Envi­r­ onment Agency (Bundesumweltamt) demonstrated the presence of carcinogenic (cancercausing), mutagenic and teratogenic (toxic to reproduction) substances, so-called “CMR” materials, in plastic wall and floor coverings. There is also a risk of them causing serious dioxin contamination when burnt [17]. Bitumen, a mixture of high-molecular hydrocarbons with a little sulphur, oxygen and nitrogen, is easy to separate and recycle, but its heating value, which is similar to that of heating oil, means that it is often used in energy generation at the end of its useful life [18]. The limited durability of oil-based products in sealing or window profiles means that recyc­ ling strategies for their reuse are not really ­feasible. The recycling potential of mineral materials

Like metallic materials, mineral materials are extracted from the ground. Here too, the result is the destruction of soil structures that have developed over millennia and whose natural regeneration takes much longer than the useful life of a building. All natural stone extracted from quarries is unique in its formation, structure and colour. Relatively little energy is required to extract and process natural stone because it is produced without a combustion process [19]. However, this is not the case for most of the other materials in the minerals group, production of which requires very high quantities of energy (e.g. cement at approx. 4,000 MJ/t, concrete at approx. 7,000 MJ/t and sand-lime brick at approx. 2,000 MJ/t) [20]. The recyclability of these materials at the end of their “lives” is limited. To produce a mineral product with the same quality as the original product, it can usually only contain a maximum of 50 % of secondary material (e.g. masonry blocks or float glass), depending on the construction materials group it comes from. The basic materials that mineral construction products are made of are generally regarded as almost inexhaustible. Sand however, one of 62

the most common and sought-after primary mineral raw materials, is disappearing at a ­dramatic rate. River sand in particular, which is found in rivers, lakes and seas and whose grain and coarse structure make it suitable for making concrete and glass as well as many other basic everyday products, has become a scarce commodity for which there is almost no substitute [21]. According to the United Nations Environment Programme, more than 30 billion tonnes of sand is consumed globally every year [22]. Apart from water, no other material is consumed on such a scale. Easily and inexpensively accessible deposits have now been used up, so floating dredgers are extracting sand for building from the seafloor. This destroys ecosystems on the seafloor and in the water column above it. Sandbanks that protect coastlines from flooding are also being dug up. All along the coasts of North Africa, beaches are being ­illegally removed – in Morocco 50 % of them already have been [23]. When mineral construction materials are subjected to further use, the main product to emerge out of the recycling process, which involves considerable losses, is usually aggregate [24]. Demand for aggregates in construction as a whole is large. To date, only between 10 and 15 % of them have been made of reused materials, so substituting naturally occurring sands, gravels and natural stone for secondary construction materials is both expedient and necessary. Approximately 80 % of all mineral construction materials are downcycled, over 15 % are used in filling and landfill construction and the remainder is disposed of in landfill [25]. For mineral construction materials, the recyc­ ling strategy of reuse can be advisable. Various parameters determine the likelihood of reuse for the same purpose. The material must reach a certain level of quality and long-term durability needs to be guaranteed, usually in the form of resistance to weathering and ageing. Large-format, thick panels of natural stone that can be disassembled without being destroyed increase that material’s economically efficient chances of ­reuse (see “Circularity in Architecture – Urban Mining Design”,

p. 10ff.). Mineral mate­rials can largely only be retained in closed cycles by means of reuse. Figure B 2.3 shows the recyc­ling potential of materials of various origins. Recycling and global warming potential

A material’s extraction, production and transport as well as its use in energy generation usually produces waste in the form of carbon dioxide (CO2). Increasing amounts of CO2, a greenhouse gas, are regarded as the main cause of global warming. Global warming potential is a significant indicator in the life cycle assessment of a construction material and is expressed in CO2 equivalents. Biotic materials are far better than fossilbased materials for the purposes of reducing air ­pollution, so their use is a fundamentally better strategy than to avoid waste, even though in both cases combustion or rotting at the end of the material’s life generates CO2. While CO2 that has been stored over millions of years is emitted when fossil-based materials burn, during their relatively short growth phases biotic ma­terials bind the same amounts of CO2 that they release at the end of their lives when they rot or burn. Wood for example, is an important carbon store. If wooden ­products replace those made of fossil-based materials or those whose manufacture emits a high level of CO2 (e.g. cement), there is a ­double benefit [26]. Our primary objective must be to choose construction materials that use the least possible amount of primary energy in their production, usage, end-of-life phase, and when recycled. This will be especially important as long as our energy generation is not yet based entirely on renewable resources. The CO2 emissions generated by the recycling of materials in technical renewal cycles can only be avoided on a large scale if recycling is carried out using only renewable energy in future. As long as our mobility depends heavily on the combustion engine, CO2 emissions will only be kept in check by avoiding long transport routes, so it can make sense to prefer locally avail­able construction materials (see “Eco-­ Efficient Construction Using Local Resources”, p. 36ff.). Recycling can, however, result in

The Recycling Potential of Building Materials

higher CO2 emissions because routes to highly specialised processing facilities are currently often longer than those to the nearest landfill site. Landfill space in Germany is, however, becoming increasingly scarce, so this option is often not available (see “Limited landfill capacity”, p. 124). Examples of Materials: Fundamentals and Evaluation The examples of materials and products described on page 65ff. are sorted into structural component and product groups and have

biotisch verwertbar

Material der Rohstoff

ert ukt e

l

been selected with a view to raising the readers’ awareness of current and future reuse as well as recycling problems and opportunities. Recycling potential and reuse: Material Cycle Status

Material Cycle Status diagrams developed at the University of Wuppertal show the prospects of selected materials and products for reuse and further use and can be seen as an approximate quantification (average f­igures, with discrepancies possible). The diagrams use three bars to show the recycling prospects of each of the products or materials (Fig. B 2.4 a, p. 64).

biotisch Biotically weder utilisable biotisch verwertbar noch technisch verwertbar

Neitherbiotisch biotically weder nor technologically technisch nochutilisable technisch verwertbar verwertbar

biotisches Material biotisches Material Biotic material, Biotic material, nachwachsender Rohstoff nicht nachwachsender Rohstoff Mineralischer biotisches Material renewable resource non-renewable resource Rohstoff nicht nachwachsender Rohstoff

nicht nachhaltig zertifiziert zertifiziert kultiviert bedrohte Pflanzennicht nachhaltig nachhaltig Certified, Not sustainably nachhaltig oder Nebenprodukt sustainably cultivated oder Tierart certified,(kultiviert) zertifiziert oder vorrangige orohne by-product without notgeerntet sustainably oder Nebenprodukt nachhaltig (kultiviert) competing utilisation cultivated or Nebenprodukt mit Nutzung mit vorrangiger geerntet oder harvested, schwach Nutzung Nebenprodukt mit or by-product with konkurrierender schwach competing utilisation Nutzung konkurrierender Nutzung

Closed-loop closed material loop-material

bedrohte Pflanzenoder Tierart

nur anteilsweise Endangered plants zur Nebenprodukt oroder animal specieseines Herstellung mit vorrangiger or by-product Produktes gleicher with higher-ranking Nutzung Qualität verwertbar utilisation

einmalige Nutzung führt zum Verlust

Mineralischer Mineral Rohstoff Fossiler raw material Rohstoff

nur anteilsweise zur Herstellung nahezu 100%eines Only partially usable Produktes gleicher for the manufacture verwertbar, jedoch Qualität of averwertbar product nach mehreren of equal quality Verwertungsprozessen Verlust an Qualität

SingleNutzung use einmalige loss führtleads zumtoVerlust

Material Recycling Content – MRC The MRC bar shows the recycling content with which a material or product is currently made. The data was drawn from general sources and from product-specific information (e.g. from manufacturers’ specifications, product information and EPDs). Material Loop Potential – MLP The Material Loop Potential (MLP) bar shows how high the proportion of recycling content could ideally be if production was completely

B 2.3  Recycling potential of various materials

technisch Technologically utilisable verwertbar

Fossiler Fossil-based Rohstoff Metallischer raw material Rohstoff

nahezu 100% verwertbar, jedoch nahezu 100% Nearly 100 % usable, nach mehreren though und loss verwertbar Verwertungsprozessof quality occurs immer wieder after several en Verlust anzur Qualität verwertbar processing cycles Herstellung eines Produktes gleicher Qualität

closed loop-material

Metallischer

Metallic raw material Rohstoff

nahezu 100% verwertbar und

Nearly 100 % usable, immer wieder recyclable for verwertbar zur manufacturing a producteines Herstellung of equal quality Produktes gleicher

Qualität

Closed-loop closed material loop-material B 2.3

63

optimised in terms of its proportion of secondary raw materials used. The information is based on series of tests and trials conducted by scientific institutes and by industry associations and on statements made by production companies. This kind of production, which is optimised to make the best use of materials cycles, is currently not possible in many cases because of a lack of recycling resources. Secondly, the fact that current material flow input into construction is about three times as high as the output of material from demolitions also plays a role [27]. The recirculation of materials from a manufacturer’s own production processes (pre-consumer or pre-use materials) does not count in the recyc­ling ratio in MRC and MLP. This is because it is attri­buted to the efficiency of the process tech­nology and the material generated as a by-­ product of other production processes, as do such materials not coming from the targeted recirculation of formerly used and reprocessed products or construction wastes [28]. The recycling cycles of materials that are byproducts of natural production processes (e.g. new sheep’s wool) are only regarded as closed when the material used in the primary manufacture or original purpose is certified as sustainable and as long as they could not be recycled for another purpose that would take precedence in a “pyramid of needs” and be of higher priority (see “The recycling potential of biotic materials”, p. 60f.).

Figure B 2.4 a depicts and illustrates these ­ valuations. The MRC and MLP bars e show the proportion of recycled material in black and the proportion of new materials in white. Renewable raw materials in the ­product are indicated by light or dark green; dark green when the material certified was ­sustainably raised or cultivated. Closed-loop materials are also shown in black and dark green. Material End of Life – MEoL The Material End-of-Life bar shows what currently happens to the construction materials at the end of their life cycle. Black indicates the proportion of materials that could be recycled without loss. The grey scales represent various downcycling stages. White indicates loss. The data was derived from general sources (e.g. statistics on waste commissioned by the German Federal Government and information provided by industry associations). Other recycling potential

Apart from opportunities for reuse and further use, other potential types of recycling are also shown (Fig. B 2.4 b). The closed-loop potential of biotic raw materials A lack of regulation means that it is currently barely feasible to consign single-variety biotic construction materials to the natural cycle to rot and humify. Materials and products that

can undergo composting in future are labelled with a “Compostable” symbol. Potential for reuse and manufacturer take-back The potential for reusing a construction product or parts thereof is fundamentally limited. A dependency on demand and the remaining efficacy of the used product make it hard to assess prospects for its reuse, so we will not attempt to make a quantitative evaluation. Products that can be reused are labelled with a “high potential for reuse” symbol. The prerequisites for reuse are durability, value retention (demand / market), the absence of pollutants and the possibility of easily removing the product unmixed with other substances without destroying it (and maintaining its form). Information on the materials’ durability is based on EPDs, other manufacturer specifications, the German Assessment System for Sustain­ able Building (Bewertungssystem Nachhaltiges Bauen – BNB) “Durability of Structural Components for Life Cycle Analyses” (“Nutzungsdauern von Bauteilen für Lebenszyklusanalysen”) table and Austrian reference figures on dur­ ability [29].

Products that manufacturers will take back are specifically labelled as such. They indicate a specialWiederverwendung kind of responsibility for a product and Verfüllung/„La pioneering product design based on the prin­ Deponie Kl. 0 ciples of closed materials cycles and waste reduction. Deponie Kl. I & Wiederverwertung

‡ Recycling at equal quality level ‡ Downcycling within construction sphere, high level of quality ‡ Downcycling outside of construction sphere, low level of quality   No clear differentiation between high and low quality levels possible ‡ New material from renewable, certified sustainable resources ‡ New material from renewable resources New material or disposal or loss

Wiederverwendung Weiterverwendung

Verfüllung/„La Deponie Kl. III Deponie Kl. 0 Gefahrenstoff

Wiederverwertung Weiterverwertung

Deponie Kl. I &

Weiterverwendung Herstellerrücknahme

Deponie Kl. III Gefahrenstoff

Weiterverwertung

Symbol: “potential for composting” Kompostierung Material Recycling Content (MRC) Symbol: “manufacturer take-back” Herstellerrücknahme

Energetische Verwertung

Material Loop Potential (MLP) Material End-of-Life (MEoL) 0% a

64

20%

40 %

60%

80%

Symbol: “high potential for reuse” Wiederverwendung

Verfüllung/„La Deponie Kl. 0

Wiederverwertung Energetische Verwertung

B 2.4Deponie Kl. I &

Kompostierung

100% b

Weiterverwendung

Deponie Kl. III Gefahrenstoff

The Recycling Potential of Building Materials

The tables in Figures B 2.14, B 2.25, B 2.29, B 2.33, B 2.34, B 2.42, B 2.46 and B 2.51 offer an overview of the Material Cycle Status of specific materials and products described in various product groups and also provide parameter values for specific materials. Foundations and Support Structures DIN EN 1990 regulates the durability of ­support structures, assuming a useful life of 50 years for buildings and other ordinary support structures [30]. The materials commonly used in support structures, such as timber, steel, concrete and masonry, come from different materials groups, so the possibilities for reusing them are just as diverse. Currently, planners tend to counter the various shortcomings of construction materials (e.g. in their fire behaviour or durability) with protective measures, some of which impede recycling. Below, material-immanent alternatives using a single material are described which, through the recovery of unmixed material, offer high potential for the material’s recycling. Biotic materials: wood and wood-based materials

Hans Carl von Carlowitz coined the term “sustainable forestry” in the early 18th century and it is still today the fundamental prerequis­ ite for a closed materials cycle using wood. Most of Germany’s trees are used or felled Waste wood category

before they reach the end of their natural lives. The period from a tree’s planting to its harvesting is called the “rotation period” and it varies greatly for different types of trees, ranging from 80 years for spruce to up to 180 years for oak [31]. Only monitoring by certification systems guarantees that more wood is not taken out of the forest than regrows. Among the credible global certificates for wood from sustainable forest management along the entire production and processing chain are those issued by the Forest Stewardship Council (FSC), from the Programme for the Endorsement of Forest Certification Schemes (PEFC) and Rainforest Alliance CertifiedTM [32]. Recycling wood as a material – waste and ­recovered wood When wood and wood-based materials reach the end of their useful lives, there are two ways of reusing the material besides reuse or further use: small quantities can be enabled to rot ­naturally through composting, or larger quantities can be recycled as set out in the German Waste Wood Ordinance. All property owners with more than 1 m3 of loose bulk waste wood or 0.3 t per day (in the case of dismantling) are obliged to sort, separate, collect, store, transport and recycle or dispose of it in accordance with the ­categories of waste wood set out in the Ordinance [33]. High-grade recycling or downcycling to produce wood-based materials

Waste wood category A I Untreated or solely mechanically finished waste wood that was at most negligibly contaminated with non-wood substances during use

yes

Waste wood category A II Glued and treated waste wood containing neither organic halogen compounds in the laminate layers nor wood protection products

yes

Waste wood category A III Waste wood containing organic halogen compounds in the laminate layers but no wood protection products

Waste wood is currently recycled, downcycled or energetically reclaimed. To increase its material recycling potential, the goal should always be cascaded utilisation, i.e. reuse of wood as a material through various stages must be preferred to simply using it for energy generation. In order to do so, the materials are treated in a technical recycling cycle, using downcycling processes to make less high-performance construction products. This method can only succeed if the reused product is largely free of pollutants and not mixed with other substances. Life cycle assessments show that the benefits derived from cutting emissions and saving energy are usually higher the longer a utilisation cascade is (e.g. construction timber > OSB panels > particle board) and the higher the quality of the waste wood product [34]. Waste wood in Categor­ies I and II and, to a lesser extent, waste wood in Category III, are approved for recycling into higher-quality products and as material for use in the production of woodbased products (Fig. B 2.5) [35]. Although the trend towards recycling this product has grown steadily since the 1980s, in Germany currently less than one fifth of waste wood is marketed, and that mainly goes into particle board manufacture. Most of it is still used to produce energy, without any further interim use [36]. Studies have, however, shown that around 75 % of all wood currently used in construction could

             limited Utilisation possible only if most of the coatings can be ­removed either before or during processing; because of the effort required, this is seen as a special case situ­ ation not meriting further consideration B 2.5

B 2.4 Material Cycle Status: a  Sample graphic b Symbols for additional potential types of ­recycling B 2.5 Utilisation potential for waste wood in accordance with the Waste Wood Ordinance

65

B 2.6

be integrated in cascaded utilisation because its pollutant levels are not too high to allow it to be recycled [37]. A proportion of around 3 % of glue remaining in glued timber products [38] has little impact on the material’s prospects for recycling. It is generally advisable to use wood that has been treated to the least extent possible, so as not to risk the option of recycling to make higher-quality products, which is the aim here, including in future or under tightened regulations. Whether and to what extent this is pos­ sible will often depend on the demands made on the wood, especially in terms of fire and moisture protection requirements. Protecting load-bearing and non-load-bearing wooden structural components Protective measures are obligatory for timber support structures with long service lives. They are also recommended for non-load-bearing structural components with long service lives, so this section deals not only with load-bearing timber structural components but also with nonload-bearing structural components, including those made of wood-based materials [39].

no

Natural protection for wood against fungi and insects that can destroy wood Wood tends to be mainly destroyed by fungal infestation, which in turn depends greatly on the wood’s moisture content, so the decisions taken to provide protection against fungal infestation that the standards prescribe aim to limit the moisture content of wood. Structural (protective) measures are fundamentally oblig­a­ tory (DIN 68 800-2, 5). Special structural ­measures (DIN 68 800-2, 6ff.) take precedence over other measures such as the use of dur­ able types of timber (DIN 68 800-1 and EN 350). The use of these types of timber in turn takes precedence over the use of chemical wood preservation (DIN 68 800-3). To prevent insect infestation, structural protection (visible structures that are easy to inspect) should be preferred to making structures inaccessible by obstructing and covering them, which in turn should be preferred to the use of chemical wood preservation. Only when “protection of load-bearing timber structural components cannot be ensured by structural measures alone […] and by the

no

Constant contact with ground- or freshwater

yes

no

Exposure to insect damage

no

yes

Use class GK 0

GK 1

GK 0 and GK 1: dry

yes

Building component exposed to weathering

Occasional exposure to moisture, e.g. also due to condensation

natural durability […] of the types of wood ­designated for this purpose, must additional preventative protective measures using a woodpreserving agent be taken.” [40] DIN 68 800 rates chemical wood preservation as a last resort, in keeping with the aims of pollution-free construction and using waste wood to make higher-quality products. The decision-making process to use wood’s inherent natural protection and dispense with chemical wood preserving agents in favour of recyclability can proceed as follows: • Measures to protect wood from moisture ­during production, transport and storage prior to its installation • Plans for structural protection to protect timber in finished installations from moisture, especially from water splashes, accumulations of water on horizontal surfaces and ­condensation. DIN 68 800-2 offers detailed drawings showing examples of structures that have been evaluated as positive and do not require any form of chemical wood preservation. • Classification of a wood in a use class as prescribed in EN 335 and DIN 68 800-1, 5 will

Seawater

yes

yes

Water accumulation

GK 2

no

yes

GK 3.1

GK 3.2

GK 4

GK 5

GK 3.2: often wet

GK 4: mostly wet

GK 5: constantly wet

GK 2 and GK 3.1: occasionally wet

B 2.7

66

The Recycling Potential of Building Materials

B 2.8

depend on the timber structural component’s installation situation (Fig. B 2.7). • If structural protection alone is not sufficient, a more durable kind of timber with better inherent preservation should be chosen. In making this decision, the use class is first assigned to a durability class (Fig. B 2.9) and a type of wood with the appropriate durability is then selected. DIN EN 350 provides a detailed list of types of wood traded globally from which the durability class (DC) can be derived (Fig. B 2.10). Other alternatives described in the standard are not considered here because they involve chemical wood preservation agents that prevent recycling. DIN EN 350 also sets out the resistance of woods to fungi and insect infestation [41]. The approach used in planning and using wood-based materials is similar to that used for working with solid woods. The durability class of timber products is usually measured based on the lowest durability class of one of their components. The use classes for wood-based materials are listed in Appendix C of DIN EN 68 800-1 and their suitability classified in DIN EN 13 986 [42]. The standard also refers to the necessity of using CE-labelled products because of their inherent resistance to fungi and insects (DIN 68 800-1). As the standards demonstrate, a high level of biological durability without chemical wood preservation can be achieved using domes­ tically grown types of wood (Fig. B 2.6). This approach was used in some examples

Use class (GK)

Durability classes very durable 1

durable 2

moderately durable 3

slightly / not durable 4/5

GK 2

+

+

+

–

GK 3.1

+

+

+

–

GK 3.2

+

+

–

–

GK 4

+

–

–

–

+  natural durability sufficient –  natural durability insufficient If the classification falls between two levels (e.g. 1– 2), the durability required should be determined using the lower durability class. B 2.9

Tree species

Laboratory experiment to determine resistance to fungi

Laboratory or field experiments that simulate installation in the ground

Blue gum (E. globulus) (Galicia) Lodgepole and Maritime pine, European Douglas fir, European Yew Oak Sweet chestnut Eucalyptus x trabutii (cultivated in the UK) Larch, European Scots pine Walnut Giant arborvitae (cultivated in the UK) Black locust Hardwood Thermowood (TMT)1) Coniferous Thermowood (TMT)1) Cedar

B 2.6  High durability of European wood species – ­traditional timber construction in Switzerland B 2.7  Decision process for the allocation of timber building components to a use class in accordance with DIN 68 800-1 and DIN EN 335 B 2.8  Natural fire prevention through charred surface B 2.9  Allocation of the use classes of DIN 68 800-1 to durability classes in accordance with DIN EN 350-2 B 2.10 Durability classes of selected European wood species in accordance with DIN EN 350-2016

Turkey oak 0 Note: Since there is no definitive evidence linking bulk specific gravity to resistance to fungi, the bulk specific gravities are not given here. 1)

1 Very durable

2

3

4

Durable

Moderately durable

Slightly durable

5 Not durable

Durability class

 ource: Merkblatt TMT.02 Dauerhaftigkeit von TMT (Thermoholz) 07/15-M TMT02. Published by the Institut für HolzS technologie Dresden IHD B 2.10

67

B 2.11

in this book’s “Detailed Catalogue” in cases where it was not possible to exclude conden­ sation in layered structures (see p. 135ff.). European wood produced under secured quality guidelines should generally be preferred to tropical timber, also to avoid the greater environmental impact resulting from transport. Natural fire protection offered by wood and wood-based products for various applications DIN EN 13 501-1 categorises wood and woodbased products (apart from those used as floor coverings) depending on their reaction to fire, as either Class D or E. Class E means that the product is able “for a short period to resist attack by a small flame without extensive spread of flame”. A Class D construction product is able “for a longer period to resist attack by a small flame without extensive spread of flame. It is also able to resist attack by a single burning object with delayed and limited heat release” [43]. Apart from fire behaviour, the smoke emissions of wood and wood-based products are defined. s2, for example, indicates a limit to the entire amount of smoke emitted and the ratio of the increase in smoke emission. Burning droplets and falling particles are also categorised in Class D. Construction timber is classified as d0 (no burning droplets /falling particles), which is particularly important for facade cladding. If it is necessary to improve the fire behaviour of timber structural components beyond Classes D or E, which DIN EN 13 501-1 requires them to reach, the components must be protected with further measures. This is ­usually done by cladding with panelling ­materials that are of low flammability or nonflammable. Here it must be ensured that the cladding panels are made of recyclable mate­r­ ials and attached so that they can be easily disassembled. Using wood’s intrinsic properties to provide ­mono-material fire protection, i.e. using wood to protect wood from fire, is also an option that allows for rapid subsequent dismantling and easier recovery and recycling. The layer 68

of carbon that forms on wood in response to fire protects its inner core (Fig. B 2.8). Based on this fact, timber and wood-based products can be made oversized in accordance with DIN EN 1995-1-2, and the ideal cross-­ section remaining under the layer of carbon can be considered load-bearing. Charring rates of solid wood and laminated timbers, depending on their bulk density, are on average between 0.55 and 0.8 mm/min., for panel materials up to 1 mm/min. This means, for example, that a load-bearing timber cross-­ section (> 450 kg/m3) that is exposed to fire on all sides and oversized on all sides by 35 mm will resist fire for more than 60 minutes [44]. Metallic materials: steel

Steel is a high-performance construction mater­ ial that has a major role in support structures. Around 85 % of all metal structural components used in construction are made of steel [45]. Steel is a primary raw material that is costly and complex to produce, large quantities of energy are consumed in its production, and the other environmental impacts it causes are serious, so recycling is an established part of steel production (Fig. B 2.11). Recycled steel requires only a quarter of the primary energy used to produce new steel [46]. Steel is the world’s most frequently recycled material [47]. The proportion of scrap in the structural steel products of some major European steel producers is 70 %, with half of it sourced as new scrap from production and the other half from collected capital scrap. There are many scrap collection centres (scrap dealers) all over the world. Germany is said to have collection rates of up to 99 % [48]. Based on statistics from other EU countries, it can be assumed that in Germany up to 88 % of steel used in construction is in continued use as been recycled as a material, and up to 11 % is in continued use as been reused in the form of whole structural components. In Germany, around 25 % of all non-residential buildings now consist mainly of steel structural components [49]. In the interest of establishing a real circular economy it would be desirable for this propor-

tion to increase further at the cost of mineral construction materials and be extended to include residential buildings. Like other metals, steel can be melted down and recycled an unlimited number of times to make products of the same quality [50]. Steel scrap is processed by means of sorting and crushing until the scrap has the desired purity. In the subsequent remelting process, steel can be adapted to any new requirements, after chemical analysis of the liquid steel, by alloying and further processing it. The new product can be of an even higher quality than the original [51]. As well as improving its structurally relevant properties, upcycling steel can also increase its resistance to corrosion, e.g. by making the new product in the form of stainless steel or weathering structural steel. Corrosion protection Steel is at risk of corrosion when it is exposed to relative humidity of over 80 % and tem­ peratures above 0 °C. In an environment with reactive air pollutants or in the presence of hygroscopic salts (e.g. in soil) steel can also corrode at much lower levels of humidity, humidity, destroying the material [52] and weakening the calculated cross-section that the structure relies on. Protection through oversizing One low-tech way of countering cross-section loss in a steel component due to corrosion is structural oversizing. This strategy is used when making foundations with driven piles. Depending on the structure’s useful life and the corrosiveness of its environment, the rusting rate must be included in the structure’s ­sizing so that the load-bearing cross-section is maintained until the end of the structure’s useful life. The expected rusting of unalloyed steel in the first year of installation is specified in DIN EN ISO 14 713, Tab. 1, depending on the corrosion category (C 1: very low to C 5: very high). Corrosion protection using properties inherent in the material The alloys used to make rustproof steel, also called stainless steel or high-alloy steel, and

The Recycling Potential of Building Materials

weathering structural steel (proportions of chrome, nickel, molybdenum or copper) ­protect structural components from destructive corrosion without any further measures by forming a passivation or barrier layer. This makes it possible to dispense with corrosion protection from additional coatings (see “Weathering steel”, p. 74). Over­sizing an ­element’s load-bearing core can offer further protection. Coatings and finishings Steel structures are often protected from corrosion by a zinc coating, applied either in hot-dip galvanising, where a piece is dipped in liquid molten zinc, or as thermal spraying with zinc (spray galvanisation) [53]. Here too, depending on the corrosion category, the zinc coating’s thickness is determined in accordance with DIN EN ISO 14 713-1 [54]. An average 85 μm thick zinc coating usually achieves the required protection period of at least 50 years in the atmospheric conditions prevailing in Germany and has a high mechanical load capacity. If its surface is damaged, however, by scratches resulting from screwing piles for screw foundations into the soil (see “Ground screw foundations”, p. 46) for example, cathodic protection sets in, forming a barrier against corrosion by electrochemical means [55]. Zinc-coated or galvanised steel can be easily recycled with other steel scrap in an electric steel production process. Due to its low boiling point, the zinc vaporises during smelting and is then collected in filters, and around 93 % of this material can be fed back into the zinc extraction process [56]. Organic coatings are also often used as a dec­ orative coloured form of corrosion protection. Volatile organic compounds (VOCs) that can pose a range of health risks can be released from scrap coated with plastic during recyc­ ling, so their use should be carefully considered [57]. Fire protection Steel structural components subjected to fire heat up quickly due to their often slender profiles and high level of thermal conductivity. Steel’s mechanical properties depend heavily

on temperature and steel structural components can fail quickly when exposed to extreme heat, so many support structures may need special fire protection measures such as casings or cladding made of mineral construction materials. As with timber support structures, it must be ensured that they are built to be easily dismantled, so that the steel can be separated from other substances for ­recovery and recycling. Fire protection coatings that form insulating layers in the event of fire are often used on steel components that remain visible [58]. Some of the materials used in the coatings as binding agents (e.g. vinyl acetate, which is an EC category-3 carcinogen) have, however, been criticised [59]. Fire protection measures that dissipate heat, such as the filling of hollow steel profiles with freely circulating water, can be an alternative to the use of chemicals, and oversizing can be another low-tech method of protecting structures from fire. The calculations used to determine sizes are based on those in DIN EN 1993-1-2 [60]. Mineral materials: masonry materials, concrete

Mineral materials recovered from demolitions are usually in continued use as downcycled material in the form of aggregate (see “The Recyc­ling potential of mineral materials”, p. 62). A ­decisive criterion for more sophisticated ­recycling of mineral materials from demolitions is the material’s hardness and core ­density. A high proportion of concrete and only a small proportion of other, less hard ­mineral constituents is the precondition for a higher order of downcycling, e.g. as ag­ gregate for concrete or as a base layer. Pro­ portions of softer materials (especially gypsum, but also sealing and insulating materials) that cannot be separated from construction rubble prevent the recycling of these mater­ ials in construction [61]. Concrete and brick recyclates can be generally separately recovered if further material layers are dispensed with in planning or if layer structures are built using materials from the same materials group (see “Mono-Material Construction”, p. 102ff.).

Masonry materials Masonry materials have developed in different ways in recent decades, due to the various demands made on them. The result is either light, heat-insulating blocks or heavy loadbearing blocks that each contain different basic materials as binding agents and aggregates. These constituents must be separable from each other in building rubble if each ­single group is to be recycled in the best ­possible way. Brickwork Half of all the demolished masonry material in Germany is currently brick, which is a fairly harmless material from an ecological point of view. The bricks used in support structures are usually not fired at temperatures as high as clinker brick, so they are softer and the higher proportion of voids and cavities they contain makes them more fragile. They are generally so damaged during demolition that they cannot be reused as building bricks, so the focus is on a continued use (downcycling) as brick recyclate in other products. Mortar and adhering plaster residues do not prevent the recovery of pure brick recyclate, but these B 2.11 Steel is the most recycled material worldwide. Recycling is an established, integral part of steel production. B 2.12 Brick chippings: a variety of downcycled uses range from plant substrate to terrazzo aggregate

B 2.12

69

a

b

materials can only be separated from one another in processing, to produce pure brick chippings. Brick’s brittleness and softness means that a lot of the material is lost during the sep­aration process. Also problematic for recycling are elements made of composite materials, e.g. blocks filled with plastic insulation, which must be crushed down to the smallest grain size to separate the materials and extract the pure brick. It can be assumed that these kinds of products will end up in landfill. In a classic downcycling process, brick chippings are often in continued use as a plant substratum in roof greening systems, as aggregate in terrazzo, in outdoor installations, as material replacing soil in base drainage or in frost protection ­layers (Fig. B 2.12, p. 69) containing up to 30 % of recycled material by mass [62]. Brick recyclate is currently rarely recycled to make new masonry in Germany [63]. Depending on the composition of its basic clay mater­ ial, 20 – 60 % of its primary raw material can be substituted by finely ground, quality-assured brick dust [64]. Research projects have succeeded in making expanded granulate out of mineral construction waste for use as lightweight aggregate [65]. In Austria, a test ­production of recycled hollow block bricks showed that construction bricks with good load-bearing capacity and thermal insulation properties can be made with 70 % of recyc­ late by mass [66].

Aerated concrete masonry Its looser structure and limited strength give aerated concrete good thermal insulating ­properties and low bulk density. Reusing it as aggregate recyclate in load-bearing concrete structural components or dry bulk for base ­layers is, however, not advisable. The chemical composition of aerated concrete aggregate means that it can only be used as a water-­ storing substratum for a small range of plants. Re-using whole elements (structural slabs) may seem expedient, but high transport costs usually make this unprofitable. Recycled aerated concrete is not currently used in high-quality applications on an industrial scale, to make bricks (slabs) with a high proportion of aerated concrete recyclate, for example [69]. However, in new products containing 100 % pure aerated concrete, which is otherwise only achieved in fresh aerated concrete, it could partly replace ordinary aggregates such as sand, quicklime, Portland cement and gypsum plaster. A maximum of 15 % of recycled aerated concrete by mass can currently be used in highly insulating ­products. In more load-bearing, less insulating products, according to one manufacturer, it could be substituted in up to 20 % of the ­aerated concrete dry mixture and in up to 40 % of the mixture used to make non-load-bearing interior walls. This manufacturer also offers a composite thermal insulation system matching these products that is made of the same basic material, so in terms of its waste fractions it can be described as a monolithic, mono-material structure, which has advantages when it comes to demolition (see “Dismantling, Recovery and Disposal in Construction”, p. 16ff. and “MonoMaterial Construction”, p. 102ff.). The same manufacturer’s advertising states that it takes back unmixed waste and feeds it back into the production process or uses it as granulate [70].

Sand-lime brick masonry High-quality continued use of sand-lime brick masonry is limited. Like brick, it is almost impossible to reuse. Recycling the material to make new sand-lime bricks is not done on an industrial scale [67], although laboratory tests in the Netherlands have shown that 20 % of the nat­ural sand in sand-lime brick can be replaced with sand-lime brick, concrete and brick rubble without fundamentally impairing the sand-lime brick’s properties, apart perhaps from its op­ tical qualities. Sand-lime brick is unsuitable for reuse in substrata for vegetation. It can be added to concrete aggregate at a maximum of 10 % of the concrete’s volume, but otherwise it detracts from the concrete’s strength [68]. 70

B 2.13

Concrete Concrete is a high-performance building ­material from a structural point of view. Its plastic formability combined with fire safety advantages make it unique. Deployed at the right thickness and with appropriate detail ­construction, it can be used to make water-

proof cellars without the necessity for adhesive sealing materials. Of all construction materials used in Germany, concrete accounts for the highest proportion, with over 40% by mass [71], so its recycling potential is of particular importance. Concrete is made of mainly regionally sourced aggregates, water and its binding agent, cement, which is energy-intensive to produce. It is vital to conserve the gravel used in aggregates as a resource, because its extraction often competes with other land uses such as agriculture and forestry, drinking water production or leisure uses [72]. The German Environment Agency is seeking to reduce gravel consumption by using 25 % of recycled aggregates by 2050 [73]. Decades ago, a complex experiment succeeded in breaking down concrete into its constituents of gravel and hardened cement, which could now be done by means of electrodynamic or electrohydraulic fragmenting. The advantage of this process is that it can be used to reclaim round gravel instead of just crushed material. Crushed material can partly replace round gravel, but the cavities and voids resulting from its use mean that it requires either more cement or the addition of a concrete plasticiser. Large-scale industrial implementation of this process in the near future is unlikely and it must also be determined whether the conversion of hardened cement into reactive cement is technically and economically feasible. Large quantities of waste materials are ­expected in the coming decades and their ­recycling is focused on the continued use of aggregates, the ­proportion of which in the total concrete mixture in dry mass is approximately 86 % [74]. B 2.13 Recycled concrete aggregate a Landscape protection through replacement of natural gravel b Output of a recycling facility: various types of aggregate B 2.14 Material Cycle Status: Foundation and Structure MRC = Material Recycling Content MLP = Material Loop Potential MEoL = Material End of Life (see also sample graphic Fig. B 2.4 a, p. 64)

Metallic materials

Biotic materials

The Recycling Potential of Building Materials

Material Foundation and structure

Thermal conduc­t­ ivity [W/(m K)]

Bulkspecific gravity [kg/dm3]

Compression / tensile strength [N/mm2]

Fire behaviour [DIN EN 13 501-1]

Structural timber (KVH) from conventional forest ­management

0.15

3.5 – 5.5

16 – 29 1)

D-s2 d0 2)

Glued laminated timber from conventional forest ­management

0.15

4.1 – 4.5

24 – 32 1)

D-s2 d0 3)

Structural steel  *) (rolled sections and heavy plate)

40 –57

7.85 – 7.96

340 –730 4)

A1

Vertically perforated masonry brick

0.5 – 0.68

1.2 –1.6

4 – 28

A1

Mineral materials

Sand-lime bricks  *)

Material Cycle Status

Additional recycling potential

0  %   20  %   40  %   60  %   80  %   100  %

MRC MLP MEoL

0.5 –1.3

1.2 – 2.2

4 – 60

MRC MLP MEoL MRC MLP MEoL

MRC MLP MEoL

Wiederverw

MRC MLP MEoL

Wiederverw Weiterverw

MRC MLP MEoL

Wiederverw Weiterverw Herstellerrü

A1

Aerated concrete brick  *) for exterior walls with no additional thermal insulation

0.08

0.35

2.0

A1

Aerated concrete brick for exterior walls with additional thermal insulation  *) 6)

0.12

0.5

4.0

A1

Aerated concrete brick for non-load-bearing interior walls  *)

1.4

Structural concrete C12/15 – C50/60 7) 8)

2.1

MRC MLP MEoL 0.5

–

12 –50 5)

A1

Wiederverw Weiterverw

Wiederverw Weiterverw Kompostie

Weiterverw Herstellerrü Energetisch

Weiterverw Kompostie

A1 MRC MLP MEoL

2.0 – 2.6

Wiederverw

MRC MLP MEoL

Herstellerrü Energetisch

Kompostie

Energetisch

*) Data supplied by the manufacturer; they refer to select products and are not applicable to the entire product category. compression strength parallel to grain  2) building components of > 20 mm thickness  3) > 380 kg/m3 and > 40 mm thick  4) tensile strength only 5) fcs, fcyl = characteristic strength of cylinders with a 150 mm diameter, 30 mm length, 28 days old  6) additional insulation necessary for exterior walls  7) no steel component, exposure class XC  8) MLP: recycled aggregate type 1, maximum proportion of recycled aggregate by DIN 1045 in accordance with DafStB regulations B 2.14 1)

71

B 2.15

The German Committee for Structural Concrete (DAfStb) guideline prescribes a limit to the proportion of recycled aggregate of 45 % and, to date, this has only been used in concretes up to strength class C 30/37 [75]. Cement and other additives cannot be substituted. Increasing quality requirements and the problem of recovering strictly separated materials due to the adhesion described above have so far prevented the use of secondary raw materials in new concrete structural components. In Germany, only 0.5 % (EU-wide about 6 %) of concrete rubble is currently reprocessed for use as recycled aggregate in new concrete [76]. In 2006, materials tests in Switz­ erland showed, however, that high-quality concrete can be produced even with the use of over 90 % of aggregates made of scrap mater­ ial (see “A statistical overview”, p. 19) [77]. Surveys have shown, however, that only 40 % of aggregates from concrete rubble are suit­ able for use as recycled material because only certain grain sizes can be used in the grading curves (Fig. B 2.13, p. 70). The remaining 60 % of concrete rubble can only be further used in a downcycling process at a lower quality as a substitute for primary bulk materials in base or frost protection layers [78]. Transport costs mean that recycled concrete production is only profitable when the secondary raw materials source is close to the site where the new building is being built, and is best done in the form of on-site recycling (see “Eco-Efficient Construction Using Local Resources”, p. 36ff.). Prefabricated components can usually be ­recycled only in rare cases, due to transport costs.

B 2.15 Split larchwood shingles with high longevity, ­Caplutta Sogn Benedetg (Chapel of the Holy ­Benedict), Sumvitg (CH) 1989, Peter Zumthor B 2.16 Uncoated timber composite panels: a visible ageing process, rehearsal building in Batschuns (AT) 2002, Marte.Marte Architekten B 2.17 Reed: a versatile, shapable material, Wadden Sea Centre, Ribe (DK) 2017, Dorte Mandrup B 2.18 Thermally modified wood: local ash becomes long-lasting. Hospital, Thy-Mors (DK) 2013, Friis & Moltke Architects

72

Exterior Walls, Pitched Roofs: Exterior ­Surfaces Buildings’ visible envelopes are essential. They largely determine a building’s design and external expression. Quality demands made on exterior structural components have constantly developed in recent decades. While support structures are assumed to be durable for 50 years, replacing or retrofitting a building’s envelope every 25 years is now seen as realistic. Apart from thermal insulation, sound insulation or further burglary protection functions will be added in future: the building envelope will act as an energy generator, as a green space, or as a digital or analogue exchange platform (see “Flexible facades”, p. 12). The cost and effort involved in manufacturing different forms of exterior building cladding vary greatly. Due to their slight material thickness, a lightweight substructure is enough for sheet metal and metal cassettes, and the same applies to plastics and wood-based materials, due to their surface weight. The materials required for cladding and the demands it makes on a substructure increase greatly with the use of mineral building mater­ ials, which have traditionally been better suited for solid structures. A major advantage of these materials compared with plastics or ­timber is their durability. The material must be precisely matched with its application. Some materials in rear-ventilated facing shells are less durable than those in other structures, which planners can respond to by increasing the material’s thickness [79]. To make good use of urban mining, it is advis­ able to give preference to a value-adding metal building envelope (see “Cost Comparisons of Conventional and Urban Mining Design Constructions”, p. 120ff.). Such metal envelopes had fallen into disrepute because of the leaching out of hazardous substances in rainwater due to weathering in the past. More recent surveys have shown, however, that substances leached out of copper or zinc surfaces can be very well biologically purified and filtered in open green seepage hollows on site, making them as harmless as the German Federal Water Act (Wasserhaushaltsgesetz) requires [80].

Facade cladding is often also used on the ­surfaces of pitched roofs to give buildings a sculptural appearance, so both these structural components are considered together here. Some of the exterior cladding discussed below is also suitable for use in interiors. Biotic materials

Renewable raw materials are advisable for both ­economic and ecological reasons, including their use in exterior wall cladding. The flammability of materials, their highly differing levels of durability and consequent potential changes to their appearance must be taken into account in the decision process. Solid wood The durability of solid wood (and wood-based materials) exterior cladding varies greatly and will depend on the application, the structural protection provided for the wood, and the type of wood used (see “Protecting load-bearing and non-load-bearing wooden structural components”, p. 66ff.). Weathering changes timber’s appearance. Larch wood for example, turns from orange to black under strong solar radiation, while it turns a silvery colour on the side exposed to weather or due to the frequent presence of moisture in the base area resulting from leaching after rain. If the wood’s original colour is to be retained in the long term or if a specific colour is desired, it can be oiled (also using ­coloured pigments). Surface coatings must be renewed every 2 – 5 years, depending on the direction they face. Synthetic resin varnishes and products containing biocides should not be used in the interests of a subsequent cascaded continued use of the wood (see “The recycling potential of biotic materials”, p. 60f.). Timber can also be charred in a controlled way to create a slightly shiny black surface that can conserve it for longer. This charred layer can protect the wood underneath from pests, although wood durable enough for the specific appli­cation should be chosen. In Central Europe, the most durable cladding is larch shingle cladding. The German Assessment System for ­Sustainable Building (BNB) durability table attests to its service life of more than 50 years [81]. Traditional construction has long

The Recycling Potential of Building Materials

since achieved much longer durability with the use of durable types of timber, the preservation of fibres due to skilled manual timber splitting, and a vertical orientation of shingles in the direction of the wood’s fibres that facilitates storm water run-off (Fig. B 2.15). Fire safety measures have been dealt with in the section on “Natural fire protection offered by wood and wood-based products for various applications” (p. 68). Thermally modified timber Thermally modified timber (TMT) dispenses with chemical preservation or coatings and can be very durable (Fig. B 2.18). All domestic types of wood can be used to make thermally modified timber, including those that are not naturally very durable (e.g. beech, ash, aspen or pine), which can be a cost advantage. Wood is heated to temperatures over approx. 160 °C, while its oxygen content is reduced, which thermally modifies it without the need for any further additives. TMT keeps its form very well, so it is predestined for use in door and window frames. Such frames are made by gluing together several layers and at the end of their lives they are classed in waste wood category II (or if unglued, in waste wood category I). TMT can have a service life of up to 25 years, even when untreated and fully exposed to weathering (Fig. B 2.5, p. 65). Due to the production process and depending on the type of wood, TMT is usually dark brown and fades as it weathers [82]. The production process can reduce the timber’s strength [83], so a certificate of usability from building regu­ latory authorities is required for load-bearing structural components. For non-load-bearing components, e.g. facade cladding, it should be ensured that the timber is of a durability class sufficient for the application class [84]. TMT is an interesting alternative to other ­durable types of high-quality timber (Fig. B 2.10, p. 67). Composite wooden board Veneer or laminated wooden boards can be useful when large planar formats are used to shape a surface’s appearance. They are available in thicknesses ranging from 12 to around

B 2.16

B 2.17

70 mm. Further surface protection, such as paint, can be dispensed with on thicker boards (from approx. 25 mm) (Fig. B 2.16). Thicker top layers (> 3 mm) or face veneers of more nat­ urally durable timbers can then be used [85]. Composite wooden board is made of hardwood and /or softwood veneers that are often bonded together with waterproof thermosetting adhesives, so it should be ensured that the ­formaldehyde content in the adhesive is as low as possible, to protect health and the environment. Use of this board for exterior applications must also be verified as compliant with the relevant standards or by a certificate of usability from building regulatory authorities.

The boards’ surfaces are sanded or brushed and turn grey over time. Recycled material has so far not been used to make veneer and laminated wooden board [86]. At the end of its life cycle, laminated waste wood is mostly used in energy generation because of its high heating value [87]. Facade panels made mainly of wood or paper fibres embedded in hardened phenol formaldehyde resins (approx. 30 %) (High Pressure Laminate – HPL) will not be discussed in this section. Fire protection additives are added to these panels and their coloured surfaces are produced by the application of acrylic-urethane

B 2.18

73

B 2.19

coating [88]. There is no potential for recycling these kinds of composites apart from their direct use in energy generation. Thatch Thatch, i.e. dried reed, is harvested around bodies of water or in marshy land, mainly in Poland, Hungary, Romania and Turkey. The emissions generated by transporting thatch mean that intercontinental imports are not recommended. It is delivered in bundles and laid by skilled craftspeople to form 25 – 40-cm-thick roof ­coverings or facade cladding attached to battens with stainless steel or copper wire (Fig. B 2.17, p. 73). The reeds are 1.50 to 2.30 metres long and 3 to 12 mm in diameter. Thatch roof coverings have an average life­ span of 30 years. However, this depends on the material, the roof’s form and orientation, wea­thering, and care and maintenance and can vary greatly [89]. As a purely natural product, it can be composted at the end of its life, so it should not be treated with algaecides to extend its lifespan and should be maintained by exclusively mechanical means. Fire safety regulations can mean that these structures must have interior board cladding, which may not, however, have a high potential for further use. Fire protection coatings are available for thatch, but they coun­teract the advantages of its natural qualities and can impede the option of composting the material [90].

B 2.20

74

Metallic materials

Metals are appealing compared with other building materials because of their durability, ease of maintenance, the value they add and their performance. Facades can be clad with very thin metal layers (around 1 mm) on light substructures. Coated steel Sheet metal used for exterior wall or roof cladding must be corrosion-resistant. If the desired lifespan of cladding in a rear-ventilated facade situation cannot be achieved with the durability of steel sheeting and a minimum layer of zinc coating, the coating can be thickened or the metal protected with a plastic coating. Metal recycling is not impaired by either surface treatment. A zinc coating is the better solution because 100 % of the material can be recovered, which is the ultimate aim of recyc­ ling. Further coatings can be dispensed with if weathering or stainless steel is used. Stainless steel Stainless steel, also called rustproof or highalloy steel, forms a thin surface coating of chromium oxides when exposed to oxygen. This socalled “passive layer” not only protects it from corrosion, it also helps it resist acids and salts. Stainless steel is therefore used not only in facade cladding but also in support structures that are exposed to an aggressive environment. If the oxide layer is damaged, it quickly regenerates, thereby “repairing itself” [91]. Weathering steel The special alloy of weathering steel means that, when exposed to weather, it forms a ­stable, constantly renewing, oxidic top layer of red-brown to orange rust within weeks or months (Fig. B 2.20) [92]. Since this occurs at the cost of the material’s thickness, a rust allowance must be added to the thickness of profiles or sheet metal that the structure requires. This is calculated depending on the corrosive properties of the surrounding atmosphere and the structural component’s life cycle. Weathering steel is also subject to special construction principles: continuous moistening of the structural component must

be avoided (with a well-ventilated structure, no contact with soil) as well as contact with concentrated salts (e.g. in areas near the sea or exposure to de-icing salts) [93]. Aluminium Aluminium is the most common metal in the Earth’s crust. A shortage is not foreseeable, although its manufacturing process involves a high-potential hazard from the waste it creates. Primary aluminium is made from bauxite ore, which produces a toxic red sludge as a waste by-product when mixed with sodium hydroxide. Structural components made of aluminium or its alloys form an oxide layer on contact with air that protects them from corrosion. This makes its shiny silvery surface pitted, rough, whitish and matt, so it looks quiet unsightly. One way of providing a decorative surface coating is anodic oxidation, which can produce oxide ­layers on the aluminium’s surface that are 50 to 5,000 times thicker than its natural oxide “skin”. Anodic oxidation is formed by transformation of the top layer of the aluminium oxide, which becomes as hard as ceramic material and stable. The oxide layer’s colours range from transparent to grey, light and dark bronze up to black. A wide range of colours can be produced by dyeing anodic layers with organic or anorganic dyes or electrolytically in a solution of metal salts. The strictly separated recovery of the around 1,000 qualities of aluminium most frequently used plays a major role in its recycling because, if the number of minor constituents resulting from multiple recycling processes increases over time, the recycling of alloys reaches its limits, negatively impacting the properties of secondary aluminium. These impurities are currently almost impossible to remove from the molten mass with reasonable expense and effort and without loss (see “Joining and Materials”, p. 13f.) [94]. For recycling purposes, it is therefore advantageous to give raw aluminium corrosion protection in the form of an organic coating, which is easier to separate in recycling than is often the case with profiled panels [95]. This surface protection makes it possible to dispense with constituents of aluminium alloys that can restrict its recycling.

The Recycling Potential of Building Materials

Zinc Zinc sheeting for use on roofs or facades ­consists almost entirely of zinc (> 99.99 %) [96]. Zinc structural components develop ­natural corrosion protection when exposed to weathering in the form of a zinc carbonate layer, although in the process the metal’s look and feel changes from silvery and smooth to matt. Pure zinc can be recycled any number of times without damage to its physical or chem­ ical properties. From carefully sorted collections, zinc can be recycled to 95 %, from zinccontaining waste only up to a maximum of 84 %. Zinc can also be extracted as a sec­ ondary raw material from other recycling sources [97]. This is done on a large scale, with half the zinc used for galvanising steel in construction recovered from recycling as Waelz oxide [98]. Copper Construction is the largest consumer of copper worldwide, in applications ranging from pipes and moulded parts for water and heating systems up to rolled sheet metal products. Copper is made in its pure form (99.9 %) or alloyed with zinc to make brass or with tin to make bronze. Both alloys are highly resistant to corrosion. Over the course of years or decades, copper forms an oxide layer, although the feel of copper sheeting changes, as does its colour, which ranges from shiny and pinkish to reddish-brown up to turquoise green and matt (Fig. B 2.19). Copper (and its alloys) can be recycled any number of times. All the constituents of copper alloys can be separated when it is remelted, making it easy and profitable to recycle without any loss of quality. The pro­portion of recycled copper in the copper sheeting production ­process sourced from new scrap (clean ­production waste), recovered scrap (cables, electronics or sheet metal) and other recycling sources (filter dust, slurry) has reached over 50 % in Germany [99]. This makes copper the urban mining material par excellence. One German manufacturer makes full use of this potential, producing copper panels, bands and roof drainage system parts made of 100 % recycled copper [100].

Fossil materials: plastics

Plastic waste has given us perhaps the bestknown synonym for recycling made in Germany: the “Green Dot” (Grüner Punkt). Plastic recycling is, however, usually a downcycling process because, due to the material’s ­physical and chemical ageing and un­defined stabilising agent content it involves a loss of mechanical, chemical and thermal qualities [101]. Plastic is made of oil, so flame retardants are often added to it and it should be checked for any potential impact on health and the ­environment (see “Materials”, p. 13). The tox­ icity of bisphenol A (BPA), which polycarbonate contains, is underestimated according to the German Federal Environment Agency. Even in low concentrations it impacts the hormone system of people and other organisms in the environment. The regulation of its use is scheduled for review in the near future [102]. Polycarbonate (PC) panels, multiwall sheeting and hollow-chamber panels Polycarbonate facade cladding is usually offered as transparent or translucent, multilayer hollow-chamber panels, which offer better load-bearing capacity, rigidity and ­insulation efficiency than solid panels. Multiwall sheets can also be installed as air heater solar collect­ ors (Fig. B 2.21) or their chambers can be filled with aerogel to further optimise their insulating properties. These kinds of translucent insulation panels can have much better U-values than insulating glazing [103]. Their slight surface weight (< 5 kg/m2), low ­ urchase costs and limited durability make p these products suitable for applications in lightweight or temporary structures. The installation of PC hollow-chamber panels in aluminium profiles – including thermal sep­ aration – is comparable with ordinary post-andrail construction. Alternatively, they can be joined over a large surface area with an integrated tongue-and-groove joint. Like most forms of polyester, polycarbonate can be recycled at high quality many times. There are specialist PC recycling companies

B 2.21

B 2.19 Copper cladding: the perfect urban mine, service centre on the Theresienwiese, Munich (DE) 2004, Volker Staab B 2.20 Weathering steel: patina of natural corrosion ­protection, “Metal workpiece”, company headquarters, Bad Laasphe (DE) 2010, m. schneider a. hillebrandt architektur B 2.21 Polycarbonate multiwall sheeting functioning as an air collector, daycare centre, Frankfurt am Main (DE) 2015, Pfeifer Kuhn Architekten

75

B 2.22

that accept contracts for recycling it when the collection, transport and processing are profit­ able and the cost is below the prices available for recycled PC on the market. In recent years, ground PC has fetched prices ranging from 800 up to 1,000 euros per tonne and granulate has been sold for as much as 2,000 euros per tonne [104]. No information is available on whether UV-protection and colour coatings limit polycarbonate’s recyclability. Like other polyesters, PC is mainly continually used in energy generation due to its relatively high heating value [105]. One hollowchamber panel manufacturer takes back carefully separated scraps of their own product [106].

Mineral materials

Mineral exterior wall cladding is characterised by the material’s durability and resistance to combustion. The choice of available materials is large, including natural stone, artificial stone, cement-bonded panels and mater­ials containing glass. Natural stone There are 200 –250 quarries in Germany that are still in operation, despite the recent adoption of stricter environmental regulations [107]. To reduce emissions from transport, it is advisable to use regionally available natural stone (e.g. limestone). The opening of new quarries

often fails due to justifiable resistance from conservationists. Much of the natural stone now imported into Germany comes from southern Europe or Scandinavia, which is preferable, or from other continents and overseas. Apart from recycling problems, which already involve a significant loss of quality, the sustainability of these products may be further impaired (see “Recycling potential of mineral materials”, p. 62) by long transport routes and ecological or social abuses in the producing country. Among the advantages of natural stone as facade cladding are its graceful ageing and ease of maintenance as well as its durability. Stone should not be coated or impregnated in case substances leach into groundwater and so as not to compromise the stone’s reuse as non-hazardous fill or disposal in landfill at the end of its usage [108]. Limestone Limestone can be recycled because lime is one of the few mineral materials that can be used in a closed circular material cycle [109]. Building lime manufactured using pure lime mortar or plaster, can be obtained from secondary limestone material from demolition. It can be recycled if it is strictly separated during recovery, which is the greatest challenge. ­Adding any types of cement to building lime breaks the cycle and it can then only be downcycled (Fig. B 2.23)

B 2.23

76

B 2.22 Clinkers: good likelihood of reuse thanks to high ­material quality and longevity without signs of ageing, Dominikuszentrum Munich (DE) 2008, meck architekten B 2.23 Facade cladding of natural stone offcuts, residential and commercial building Apartment No. 1, Mahallat (IR) 2010, AbCT B 2.24 Glass ceramics: Museum Folkwang, Essen (DE) 2010, David Chipperfield Architects a Exterior view of the glass ceramics facade b The fused shards of waste glass are clearly delineated islands within the melt.

The Recycling Potential of Building Materials

Fibre cement and glass-fibre-reinforced concrete materials Fibre cement is a composite material made of cement reinforced with polyvinyl alcohol (PVA) fibres. It also contains other fillers such as cellulose and powdered limestone or trass and may contain colour additives (total of approx. 18 %). The products available range from small facade shingles up to large facade panels. Glass-fibre-reinforced concrete panels consist to 90 % of sand and cement. The remaining 10 % is made up of glass fibres, pigments and concrete additives. The material’s thinness (about 10 mm) and the use of raw materials it can save are its major advantages over ­prefabricated ­steel-reinforced concrete components, which are almost impossible to produce in thicknesses less than 70 mm. Fibrereinforced cement and glass-fibre-reinforced concrete panels are also suitable for use as wall cladding on light support structures or for interior construction. To date, fibre cement and glass-fibre-reinforced concrete panels have been offered in natural colours ranging from white, beige and brown shades up to black, but they are also provided in pigmented colours and with different surface textures ranging from smooth to rough. Both these panel materials are impermeable to water and frost-resistant and are also used as waterdischarging roof cladding in the form of corrugated panels. The surfaces of fibre cement panels are often coated in the factory with acrylic paint and dual-compound clearcoat, to protect them from graffiti, for example. It must be ensured that any substances leaching out of the panels are harmless. Large panels of these materials can be reused at the end of their lives, but it is almost impossible to recycle fibre cement products to make new equivalent products. Only production remnants and pure pre-consumer material can be 100 % reused in the cement industry. Cement panels are shredded for downcycling in road and path building or ­disposed of in landfill sites in landfill class DKI (Fig. A 2.9, p. 19) [110].

a

b

Clinker and brick products Exterior wall claddings made of facing brick, tile panels or clinker brick are typically used in local and traditional architecture because of the regional nature of locally available clays. Their basic colours range from white and ­yellowish through orange-red and reddishblue up to brown-black and their durability and authentic, low-maintenance ageing are their main advantages (Fig. B 2.22). There can, however, be major differences in their quality, which can greatly affect their options for reuse. Unlike tile panels or facing brick, clinker brick is fired at very high temperatures of up to 1,300 °C, so it has much greater compressive strength and absorbs less water than other clay products and is therefore very durable. The quality of clinker brick and brick products affects not only their durability and possibilities for their reuse, it can also influence their sub­ sequent further use. A maximum of 5 % brick material can be added to concrete as recycled aggregate. If only hard-fired or clinker brick is added to the recycled aggregate, this proportion can increase to 30 % [111]. The use of scrap material to make new clinker brick is also limited. Currently, only a small quantity of scrap material (< 10 %) brick dust – ground-up brick scrap from the manufacturer’s own production remnants – is incorporated into the production process, so as not to compromise the quality of products. Clinker bricks that have been used in masonry are not returned to the production process because any grout sticking to them can impair recycling and there is currently no reliable and profitable way of separating the brick from the grout [112]. In other clay products such as roof tiles, the substitution of new material by secondary material, even in manufacturing optimised for a circular materials cycle, is limited to a maximum of 40 % [113]. Clay is still regionally available in sufficient quantities for the inexpensive production of new brick, so building with reused facing brick remains the exception, although clinker brick’s qualities make it ideal for reuse (see “Facing brick shell on a load-bearing exterior wall”, p. 108f.).

Glass materials Glass recycling is a familiar part of our everyday lives. What is less well-known is the fact that high-quality products are usually only ­recycled in a downcycling process (Fig. B 2.52, p. 97). Two positive examples of facade claddings that can be incorporated into a circular materials cycle are described below.

B 2.24

Profiled glass Glass cast in U-shaped sheets is available in widths ranging from 200 to 500 mm and about 7 mm thick. Its colours range from white through turquoise-green to blue-grey, and different surface textures and levels of translucency are available. It is made of limesoda and silica glass and 30 – 40 % of glass ­recycled from construction waste. Glass sheets are suitable for rear-ventilated curtain facades and for insulating building envelopes, which are built by placing two or more sheets of glass to form an airtight bond and laying them in a frame profile so that they are thermally separated. At the end of its useful life, the profiled glass can be 100 % melted down to make the same product. Glass’s colours – the result of metal oxide coatings – do not impede its recycling and nor do integrated insulation and wire reinforcement, which can be separated out during the recycling process. Whether this is also the case with the coatings available to improve its sun protection and thermal insulating properties is unknown [114]. Glass ceramics Glass ceramics are glass products in panels made of 100 % scrap glass (pre-use and postuse material). Panels or sheets are available in thicknesses ranging from 15 up to 23 mm, which predestines them for invisible fastening using clamps with undercut anchors. They are made by heating shards of glass scrap to which sintering additives are added and are then cooled, producing translucent to opaque panels. Their colours are a result of the shards added: white from recycled solar panel glass or clear glass, jade-coloured from float glass, and green, blue and brown to black from the upcycling of container glass. 77

Biotic materials Metallic materials Fossilbased material

Material Exterior wall, pitched roof: Exterior surfaces

Fire behaviour [DIN EN 13 501-1]

Lifetime

Solid timber boards / battens from conventional forest management

D-s2 d0 1)

30 – 40 2)

> 50

Additional recyc­ ling potential

0  %   20  %  40  %  60  %  80  % 100  %

MRC MLP MEoL

Larch wood shingles from conventional forest management

E

Thermally modified wood (TMT)  *) from conventional forest management

D-s2 d0 1)

40 3)

MRC MLP MEoL

Timber composite panels from conventional forest management

D-s2 d2-d0 4)

40

MRC MLP MEoL

Thatch (reed)  *)

E

30

MRC MLP MEoL

MRC MLP MEoL

Wiederverwendu

Wiederverwertun

Weiterverwendun

Weiterverwertun

Herstellerrückna Kompostierung

Steel profile panels (galvanised, polyester-coated)

A1

40 – 45 5)

MRC MLP MEoL

Stainless steel / weathering steel, sheet  *) 6)

A1

45 / > 50 7)

MRC MLP MEoL

Aluminium sheet, varnished

A1

> 50

MRC MLP MEoL

Zinc sheet

A1

45 / > 50 7)

MRC MLP MEoL

Copper sheet

A1

> 50

MRC MLP MEoL

Recycled copper sheet  *)

A1

> 50

MRC MLP MEoL

Polycarbonate wall sheet  *)

B-s2-s1 d0

30

MRC MLP MEoL

Natural stone panels

A1

> 50

MRC MLP MEoL

Wiederverwendu

MRC MLP MEoL

Wiederverwertun Wiederverwendu

Fibre cement and glass-fibre-reinforced ­concrete panels Metallic materials

Material Cycle Status

A2

> 50

Energetische Ver

Weiterverwendun Wiederverwertun Wiederverwendu Weiterverwertun Weiterverwendun A1 > 50 Channel glass  *) MRC Wiederverwertun MLP Wiederverwendu Herstellerrückna MEoL Weiterverwertun Weiterverwendun A1 > 50 Glass ceramics  *) MRC Wiederverwertun Kompostierung MLP Wiederverwendu Herstellerrückna MEoL Weiterverwertun Weiterverwendun Energetische Ver *) Data supplied by the manufacturer; they refer to select products and are not applicable to the entire product category. The published table entries are reference values that may Wiederverwertun differ significantly from those of individual cases.  1) > 350 kg/m3 and > 20 mm thick  2) Lifetimes depend on timber species and on processing/treatment  3) Lifetime as ­facade Kompostierung Herstellerrückna cladding unknown. Comparability determined by the durability classes of suitable hardwoods  4) > 390 kg/m3 depending on material thickness and end use (ventilation of the construction)  5) Depending on application  6) MRC and MLP taken to be that of structural steel in general  7) 45 years as ventilated curtain facade, for other applications > 50 years,Weiterverwertun Weiterverwendun depending on sheet thickness Energetische Ver B 2.25 Kompostierung Herstellerrückna Weiterverwertun 78 Energetische Ver Kompostierung Herstellerrückna Facing wall clinker  *)

A1

> 50

MRC MLP MEoL

The Recycling Potential of Building Materials

The special feature of glass ceramic products is their structure, in which its production process is visible. Molten shards of scrap glass appear like “islands” in the surrounding molten mass (Fig. B 2.24, p. 77). It is not, strictly speaking, glass ceramic but waste glass that has been sintered together. It is very durable and can theoretically be reused, too. Other applications such as interior wall cladding in wet areas or as a floor covering may also be ­possible (see “Detailed Catalogue”, Example 09, p. 175ff.). One manufacturer states that they add a max­ imum of 10 % of their own scrap glass to their production process to optimise the materials cycle and guarantee the basic product’s special structure, although a much higher proportion of secondary material could theoretically be used [115]. Flat Roofs: Exterior Surfaces Flat roof coverings are exposed to the extreme effects of weathering and the climate and protect the seals below them from ageing and ­flying sparks. A roof covering added above the roof sealing allows for a loosely laid, easily dismantled layer structure and provides the weight needed to counteract wind suction. When they are walkable or planted, flat roofs generate extra spaces, living areas and also form a designed so-called fifth facade. Greened roofs offer additional insulation and so contribute to saving energy while also holding rainwater, cooling the ambient climate and providing an ecological compensation space [116]. Biotic materials: wood and wood-polymer compounds (WPC)

Solid timbers with appropriate durability and thermally modified wood (see p. 73f.) are ­currently experiencing increasing competition in their applications as flat roof or terrace coverings from product innovations such as wood-polymer compound decking boards, although wood-polymer compounds (WPC) offer no advantages in terms of durability. In contrast to natural timber, which can be used in various ways (cascade utilisation), the only

possible end-of-life scenario for these products is incineration. Mineral materials: loose waste materials

Loose waste materials can generally be reused but recycled waste materials and other production by-products (e.g. black glass cinder) are preferable to gravel or natural stone dry bulk, which is extracted from opencast mines that destroy the landscape. As well as using recycled material aggregate that can be suitable as substrata for some green roofs (see “Green roof structures”, p. 80) it is worth considering glass as a material. Glass gravel or rounded gravel made entirely of waste container glass is available in a wide range of colours (Fig. B 2.26) [117]. Surface covering slabs made of natural mineral materials laid loosely on supports (here metal should be preferred to plastic, because of its durability and recycling potential) or on sandbags can be used again. The material recycling potential of different ­coverings is comparable to that of materials in the preceding sections. Special forms

Combining a photovoltaic system with a greened roof can make a good covering for a flat roof. Green roofs lower ambient temperature, due to (evaporative) cooling, while the necessary substratum layer can weigh down the photovoltaic substructure, making it ­unnecessary to anchor it in the roof structure and penetrate the sealing layer. Photovoltaic systems Growing demand for photovoltaic technology is also increasing demand for raw materials. Current globally installed photovoltaic output of 75 GWp (2016) [118] is set to grow to 200 GWp by 2030 [119]. Aluminium, glass, silicon, indium, silver and gallium are essential in the manu­ facture of PV modules. Photovoltaic modules begin to degrade soon after they are commissioned, a process that varies in crystalline and in amorphous cells, with the performance and output of crystalline modules falling by 10 – 15 % over a 20- to 25-year period. Thin-film modules (amorphous cells) can degrade by up

to 25 % in their first year, although they barely age in subsequent years [120]. Since 2012, solar plant manufacturers have been obliged to take back PV modules free of charge and recycle them, a process regulated by the Waste Electrical and Electronic Equipment Directive implemented by the ­European Union. The PV Cycle association offers global collection of used panels. After a review of any possible reuse of their frames and electronics and after sorting, around 4 % of their materials (mainly plastic and rubber) is disposed of, after which the recovery of materials from modules begins. Generally, around 96 – 97 % of the glass, metals, plastics and semiconductor materials from PV modules can be recycled to build new systems [121]. Electronic waste recycling companies manually disassemble the inverters that turn direct current into alternating current, splitting them into their various component units and separating out the materials according to their main con-

B 2.25 Material Cycle Status: exterior wall, pitched roof: outside surfaces MRC = Material Recycling Content MLP = Material Loop Potential MEoL = Material End of Life (see also sample graphic Fig. B 2.4 a, p. 64) B 2.26 Glass gravel: as bulk fill, 100 % recycled material for recycling or reuse

B 2.26

79

B 2.27

stituents. Inverters are generally regarded as non-hazardous electronic waste for recycling purposes, but older models may have capacitors containing PCBs (polychlorinated biphenyls), which must be disposed of as hazardous waste [122]. Green roof structures A green roof’s structure consists of a separating layer and root-barrier membrane to protect the roof’s sealing as well as roof protection mats, drainage elements and system filters, then earth or a substratum and vegetation. Most roof protection mats, drainage elements and system ­filters are made of oil-based plastics. Recently a system has been launched onto the market with a drainage element made of bioplastic (also called bio-based plastic or bio-polymer). Compared with the fossil-based plastics commonly used, these can save 30 –70 % of CO2 emissions [123]. The drainage element is made of 95 % renewable raw material based on sugar cane and minerals and can be used in heat generation at the end of its “life”. In future, roof protection mats and filter fleece will be made of polylactic acid. These synthetic polymers, also called polylactides (PLA), have great potential because they can be produced to be either ­rapidly biodegradable (e. g. packaging material) or durably functional with great strength and thermoplasticity [124]. Wall, Ceiling, Roof: Structural Panels for ­ xteriors and Interiors E The structural panels discussed below make a major contribution to conserving resources in construction. As thin planking they are an indispensable element in lightweight structures. They separate spaces in frame structures in roof, ceiling and wall components and can take on load-bearing and bracing functions. As part of a building’s envelope, they regulate its transport of moisture or make it windproof, so they replace heavy solid structural components made of mineral building materials, whose potential for continued use is limited. Most of the structural panels discussed here are also suitable for use with dry screed. 80

Biotic materials

Wooden planking made at considerable expense and effort out of individual boards was traditionally used to separate spaces. For economic reasons it has now usually been replaced by composite wood panels, some containing a proportion of scrap material. ­Relatively new products with a straw basis offer another alternative. Solid wood diagonal panels Solid wood planking was used to brace timber frame structures before composite wood ­panels captured the market. The solid wood diagonal panels described in the section on “Detachable Connections and Constructions” (see p. 49, Fig. B 1.18) are a useful further development of this traditional construction method and ­render obsolete the additional installation of windproofing foils that were once necessary. The panels are vapour-permeable and made entirely of sustainable, regionally grown silver fir wood [125].

a formaldehyde limit of a maximum of 0.1 ppm, which is measured in a testing chamber using 1 m3 and 1 m2 of the board material and a ­single change of air (1/h) [126]. Composite wood board in emissions class F 0 is formal­ dehyde-free because it does not contain any formaldehyde resin-based bonding agent, but uses ­polyurethane instead. Timber itself can contain formaldehyde [127]. Using lignin, a natural constituent of wood, as a bonding agent is seen as a safe, healthy and environmentally friendly alternative.

Composite wood material panels The materials used to make composite wood products such as OSB, particle board or fibreboard come from three sources: wood from sawmill by-products, industrial roundwood and recycled materials. Sawmill ­by-products include woodchips, sawdust and shavings and cross-cuts. Industrial roundwood is a forestry by-product consisting of damaged wood and logs from thinning that cannot be cut. Recycled material comes from production waste or reclaimed timber. If reclaimed timber is used, it must be ensured that the recycled material is not contaminated with substances from old impregnation or paints and coatings that are hazardous to health (Waste wood ­categories II and III, see Fig. B 2.5, p. 65).

OSB board for exterior and interior planking Oriented strand board (OSB) is currently exclusively made of timber from thinning. The wood strands are glued together in a specific direction in three to five layers, one above the other. This direction-oriented method of gluing gives the board its rigidity, high load-bearing capacity and vapour barrier and windproofing properties when joints between the boards are taped over. Strands of the required length (up to 160 mm) cannot really be made of reclaimed timber, so strand material from reclaimed ­timber will only be considered for use in the boards’ middle layers in future. The board is classified in use classes 1 and 2, so it is suitable for wet areas and exteriors not exposed to weathering. Phenol formal­ dehyde resin (PF resin) or polyurethane resin (PU resin) is the main adhesive used (in ­proportions ran­ging from 10 to 15 %). One product available on the market is ­formal­dehyde-free and made of wood from sustain­able forestry [128]. OSB board is a so-called plus-energy product, which means that less energy is used in its manufacture and subsequent life cycle than can be produced from it by using it to generate energy at the end of its life [129].

Composite wood board contains around 3 to 15 % of bonding agent, so as well as the sustainability of the wood’s source, the quality of its bonding agent plays a major role in its use. Formaldehyde emissions in interior air from this board have often caused health problems in the past. Boards now labelled with the currently minimum legally permissible E1 standard have

Particle board for interior planking Particle board is made by pressing together dried fine strands and chips and sawdust from industrial roundwood, wood chips from forestry and recycled wood (usually fed in from the manufacturers’ own production) with a thermosetting bonding agent (around 9 %). Recycled wood’s share of all wood used varies greatly

The Recycling Potential of Building Materials

B 2.28

across Europe. In Germany and Austria it is around 30 % up to 90 % on average in Italy and 0 % in Finland [130]. Urea-formaldehyde (UF), melamine-urea-formaldehyde (MUF), phenol-formaldehyde (PF) and polymeric diphenylmethane diisocyanate (PMDI) are the main bonding agents used. ­Paraffin is also added to make products waterrepellent, and fire retardants may also be added [131]. Board containing wood from sustainable ­forestry that is glued with formaldehyde-free ­polyurethane glue (PU glue) (see “Recycling potential of biotic materials”, p. 60f.) or board made of waste wood is preferable. These boards are suitable for applications in dry and wet areas and are produced to be loadbearing and bracing as well as non-load-­ bearing [132]. Particle board used in interior applications, in built-in furniture units for example, is often coated with decorative paper, so it is worthwhile checking that the decorative paper used is formaldehyde-free. Like OSB board, particle board is regarded as a plus-energy ­product [133]. Fibreboard for exterior planking For exterior planking, there is a product made of wood fibre bonded with a formaldehyde-free MDI resin (diphenylmethane diiso-cyanate resin) and pressed. Around half of the wood comes from sustainable forestry and the rest from log thinning and sawmill offcuts. This board is suitable for use in load-bearing, ­bracing and non-lead-bearing exterior planking of walls and roofs. Its glue and paraffin wax makes it water-repellent and renders bitumen or foil sealing against rainwater unnecessary. The board is also vapour-permeable and approved for use by building inspection ­authorities [134]. Fibreboard for interior planking A vapour barrier layer is often necessary on the inside of vapour-permeable wood structures. A fibreboard that does not require certification by building inspection authorities for use in interiors is now available that meets this need. It consists of long fibres extracted from fresh

lumber that are boiled up with the wood’s own adhesive lignin to form a fibrous pulp that is heated and then pressed into boards. For the purposes of verifying its structural strength, less than 1.5 % phenolic resin is added to it in a prescribed process (boil test). A ­hydrophobic agent made of synthetic and ­natural waxes and oils makes these boards suitable for use in wet areas. Its high density enables this board to achieve values at a ­thickness of 8 mm that are comparable to those of 15 mm OSB board or 16 mm particle board. With a formaldehyde content of < 0.5 mg /100 g, the board can be labelled as formal­dehyde-free [135]. Straw structural panels for interiors One German manufacturer makes structural panels for dry construction out of cleaned straw using an extrusion process involving heat and pressure. Straw, a by-product of wheat cultivation, is regionally available, energy-­ efficient and grows quickly (Fig. B 2.27). The lignin that straw contains binds the straw ­together without any other bonding agent or adhesive in a durable, waterproof bond. ­Recycled cardboard is glued to both sides with wood glue to make a smooth top layer. The 38-mm or 58-mm-thick panels consist of 96 % straw as their core material, approx. 2 % re­ cycled cardboard and approx. 2 % wood glue and are suitable for interior walls, planking, sound insulation and installation layers. The panels can be installed as self-supporting in­ terior walls if they are screwed together offset in a double layer. Wood or metal substructures offer the greatest stiffening effect. The panels can be used in wet areas that are exposed to moderate amounts of moisture, but areas ­exposed to splash water must be additionally sealed with waterproof and permanently elastic materials or mineral materials. The process of producing a finished surface on them is ­comparable with that used for plasterboard. The manufacturer will take back straw structural panels that have been carefully separated after dismantling and they can be fed back into the production cycle. They can also be completely composted or used in energy generation [136].

Mineral materials

Loam structural panels were long regarded as the only recyclable, lightweight form of interior wall cladding, although they have a tiny market share. With the beginning of recycling, however, even a mass-market building material such as plasterboard panelling can now also be used in a materials cycle. Loam structural panels for interiors Like clay, loam has its own almost globally available bonding agent, which does not have to be activated by firing or another chemical process. Another advantage is its revers­ible plasticity. Loam building materials, unlike limestone or plaster, can be re-plasticised without too much energy expenditure once they have been carefully separated after recovery. This makes loam render very easy to repair. Loam building materials are highly water vapour-absorbent and the clay minerals bind odours and pollutants [137]. This positive effect on the indoor climate and comfort and their specific environmental properties make loam structural panels a good alternative to plasterboard and other structural panels. Mounted on wood or metal substructures, the panels can be used as facing shells, suspended ceilings and in attic conversions (Fig. B 2.28). Different manufacturers add mineral- or plant-based aggregates (e.g. reed, jute fabric, hemp and cellulose fibres) to construction loam or clay. The bridging of joints between these panels requires reinforcement so, in the interests of subsequent composting, a plant-based reinforcing fabric, made of flax for example, should be used here. Thin layers of loam render can be used as a single material to create a surface finish. The surface optics and the feel of the loam renders can be determined through ­colours and grains, the type of surface treatments available and the effects of special aggregates such as plant fibres. Loam render B 2.27 Straw structural panels are manufactured from an agricultural by-product. Panel cross-section B 2.28 Loam structural panels allow for lightweight ­construction within a biotic loop. When mounted on a timber support, they make wall heating ­possible.

81

Material Wall, floor / ceiling, roof: outside / inside structural panels

Thermal ­conductivity [W/(m K)]

Vapour diffu­ sion resistance factor [µ]

Fire behaviour [DIN EN 13 501-1]

Solid timber diagonal-board panel  *)

0.13

207/22 1)

D-s2 d0-d2 2)

Material Cycle Status

Additional recycling potential

0 %   20 %   40 %   60 %   80 %   100 %

Mineral materials

Biotic materials

MRC MLP MEoL OSB panel from conventional forest management E1

0.13

200/150

D-E-s2 d0-d2 3)

OSB panel  *) from sustainable forest management E1

0.13

200/300

D-E-s2 d0-d2 3)

Particleboard from conventional forest management E1

0.12

15/50

D-E -s2 d0-d2 3)

Particleboard  *) from sustainable forest management E1

0.1– 0.18 4)

50/100

D-s2 d0 5)

Fibreboard  *) from prorated sustainable forest management for exterior panelling E1

0.09

11

D-s2 d0 6)

Fibreboard  *) from prorated sustainable forest management for interior panelling E1

0.18

185

E-s2 d0-d2 7)

Straw structural panel  *)

0.10

10/10

E

Plasterboard

0.25

10/4

A2-s1 d0

Loam structural panel  *)

0.35

5 –10

A1 8)

MRC MLP MEoL

MRC MLP MEoL

MRC MLP MEoL

MRC MLP MEoL

Wiederverwend Wiederverwend

Wiederverwertu Wiederverwertu

MRC MLP MEoL

Weiterverwendu Weiterverwendu

MRC MLP MEoL

Weiterverwertun Weiterverwertun

Herstellerrückn Herstellerrückn

MRC MLP MEoL

Kompostierung Kompostierung

MRC MLP MEoL

Energetische Ve Energetische Ve

MRC MLP MEoL

*) Data supplied by the manufacturer; they refer to select products and are not applicable to the entire product category. 1) 10 % wood moisture/60 % wood moisture  2) depending on application, at 30 mm thickness  3) depending on application and thickness  5) for a thickness of 22 mm  6) for a thickness of 15 mm  7) depending on application, at 8 mm thickness  8) non-flammable on the interior

4)

depending on bulk specific gravity  B 2.29

82

The Recycling Potential of Building Materials

B 2.30

is sensitive to moisture, so it is not suitable for wet areas exposed to lots of moisture in the long term. Short-term exposure to water vapour (e.g. in domestic kitchens and bathrooms), however, is harmless [138]. Plasterboard interior planking Germany can currently meet its own building plaster needs. Around 40 % of it comes from quarried natural gypsum, which does, however, conflict with the German government’s eco­ logical goal of reducing the amount of land used for mining. The rest of this “building ­plaster autonomy” is based on the mining and incineration of fossil-based raw materials, which produces gypsum from flue gas desulphurisation, a by-product from brown coal and coal-fired power stations. The more the transformation of our energy ­systems takes hold, the more recycling is in demand. The technology for recycling plaster is available. Pure plaster material can be ­recycled almost any number of times [139]. In some western European countries more than 40 % of it is recycled [140]. Most German scrap material usually ends up in landfill as filler (36 %) or is disposed of (59 %) [141], which is not compatible with the goals of the German Waste Management Act (Kreislaufwirt­ schafts­gesetz – KrWG). Only about 5 % ­(including ­production waste) is recycled [142]. As with all inexpensive bulk raw materials, one

essential factor in the success of recycling, which is fairly expensive, is the relative proximity of the demolition site to a recycling plant and the proximity of the plant to the manufacturer of the new product. The mobile recycling plants of one Danish manufacturer are therefore an effective solution and result in an almost closed recycling cycle, recycling 95 % of gypsum plaster and 5 % of paper. Recycled gypsum plaster can achieve 99 % of the quality of natural gypsum [143] and it has been shown that it could currently replace about one third of the primary material [144]. Gypsum fibreboard can also be recycled if it is carefully sorted during recovery [145]. Gypsum plasterboard and gypsum fibreboard are joined at the edges using glass or plastic fibre mats embedded in a gypsum filler. It can be simply primed with a coat of paint to create a surface finish. To promote its recycling, it should be ensured that no other materials from different materials groups are added to it as far as possible (e.g. vinyl wallpaper adhered with plastic adhesives or plastic paints).

Sheep’s wool felt Sheep’s wool, a by-product of sheep breeding, can be mechanically felted to make a strong textile fabric without any bonding agents or support fibres. Pure new sheep’s wool felt, like jute fabric, can be stretched over a frame and used as interior wall cladding. This re­newable raw material can improve a space’s acoustics and have a positive effect on the ­interior climate (see “New’s sheep’s wool insulating felt”, p. 89f.).

Walls, Ceilings: Interior Surfaces Mineral materials: tadelakt

The materials described in the section on ­“Exterior Walls, Pitched Roofs: Exterior Surfaces” (p. 72ff.) have great potential for use in a mater­ ials cycle and can also be used in interiors. Metal or glass claddings, for example, are ­waterproof and can be used for construction in ­keeping with an urban mining approach, instead of gluing tiles and sealing onto composite ­panels as cladding with recycling potential in wet areas (see “Detailed Catalogue”, Example 09, p. 175ff.). The applications described in detail below are designed to be stimulating alternatives to ordinary standard solutions. Biotic materials

B 2.31

Jute fabric Jute is an annual plant that grows best in a damp, tropical climate. This rapidly growing renewable resource is non-toxic, poses no risk to health, is biodegradable (for end-of-life composting) and naturally resistant to mould and insects. Its fibres absorb and release moisture very well, so it helps to create a healthy interior climate. Spun jute can be used as cladding in interiors by stretching it on a frame (of wood, for example) and it also absorbs sound (Fig. B 2.30). Adding insulated substructures to these kinds of elements provides an additional soundproofing effect. The intermediate layer can also be used as an installation layer.

Textiles on walls or ceilings are now appreciated for their effects on a space’s acoustics. Wall hangings and hung textiles were, however, traditionally much more appreciated, being prestigious ­decorations, tellers of tales, and even a simple form of insulation.

Tadelakt is an alternative to ordinary wall coverings in wet areas, such as tiles. This smooth mineral, water-resistant plaster, traditionally installed in Moroccan bathhouses, is made of hydraulic lime, quartz sand, marble and clay powder and methylcellulose (< 1 %, to help it retain water and make the mixture easier to work). Tadelakt is white, but can be dyed any colour with pigments. Used as part of a

B 2.29 Material Cycle Status: wall, floor/ceiling, roof: outside / inside structural panels MRC = Material Recycling Content MLP = Material Loop Potential MEoL = Material End of Life (see also sample graphic, Fig. B 2.4 a, p. 64) B 2.30 Jute fabric wall lining for improved spatial acoustics, Bellevue Teatret Klampenborg (DK) 1936, Arne Jacobsen B 2.31 Tadelakt: traditional water-repellent lime plaster technique, private bath, Cologne (DE) 2016, m. schneider a. hillebrandt architektur

83

mono-mineral-material construction method, (see “Mineral Building Materials: Loam, Brick, Aerated Concrete, Insulating Concrete”, p. 104f.) it is best applied to brickwork over lime plaster. Tadelakt repels water but is not waterproof, so its substratum may have to be sealed. If woven plastic or sealing containing plastic is used for this purpose,s the advantages of using a single material are lost. Using a sophisticated manual technique, it is applied in two layers that are a total of 3 mm thick. While it is still damp, the surface layer is compacted and polished with a rounded ­tadelakt stone using circular movements and treated with an olive oil soap, which accelerates the formation of limestone. The result is a shiny, cloudy surface with a ­velvety feel (Fig. B 2.31) [146]. The recycling potential for tadelakt in a mater­ ials cycle is similar to that for natural stone slabs (see “Natural stone”, p. 76). Floor Structures Dry screeds or cavity floor structures that can potentially be recycled are preferable because they are easy to repair and dismantle. Suitable wood-based and gypsum plaster materials have been described in the section on “Wall, Ceiling, Roof: Structural Panels for Exteriors and Interiors” (p. 80ff.).

Fossil-based materials: mastic asphalt screed

Mastic asphalt screeds are not dry screeds, but have similar advantages. Mixing aggregates with the oil-based, non-toxic bonding agent bitumen (not be confused with tar) means that it can be walked on, bear loads and have another layer laid on it within a few hours. This screed is very suitable for “dry building sites” in timber or steel-frame structures because it contains no moisture. It is laid over large areas without joints and, since it does not absorb any moisture, it can be used for wet areas and outdoors (inner courtyards, patios). It can be laid and polished as a facing surface with a special aggregate (e.g. recycled brick chippings), be dyed with pigments or used to create a light, bright area. To do this, colourless mineral oil-based bonding agents are used that can be dyed. Applied in thin ­layers, they look transparent. A mastic asphalt screed facing surface, in keeping with the idea of suf­ficiency that is fundamental to sustaina­ bility, dispenses with the need for any further floor covering. It is acid- and alkali-resistant, resists de-icing salts and improves impact sound protection and spatial acoustics as well as having thermal insulating properties. Its nominal thicknesses are slight, ranging from 25 up to a maximum of 45 mm (as heated screed), depending on the load it has to bear. Its surface is softer than that of other screeds (a thermoplastic property of the bitumen), so long-term heavy point loads must be avoided if the screed is used as a finished facing surface. Mastic asphalt screed is poured at temperatures ranging from 200 to 230 °C onto a substratum (e.g. particleboard). Copper pipes are best used for underfloor heating (Fig. B 2.32) and they have a high resale value. Mastic asphalt and its aggregate can be recycled, so structures that use it have, as a whole, a high potential for use in a closed materials cycle (see “Can Loop Potential Be Measured?”, p. 108ff.) [147]. Mineral materials: ceramic tiles

B 2.32

84

Among clay products, ceramic tiles’ thinness (approx. 20 mm) and relatively low weight make them ideal for retrofitting old buildings. The tiles, which are made of fresh clay and

scrap material in form of grog (fired and ground clay), are laid dry and without mortar in half-offset formation with a special adhesive. After 24 hours, they can bear a load and have a top floor surface laid on them. When laid over underfloor heating, their high thermal conductivity means that they heat up and cool down more quickly than ordinary wet screeds. Ceramic tiles are also suitable for wet rooms. When they are used as a facing screed, brickcoloured or with surface glazes of various shades, further layers can be dispensed with. Their recycling potential is similar to that of brickwork (Fig. B 2.14, p. 71) [148]. Floors, Ceilings: Surfaces The demands made on floor coverings vary greatly, depending on their applications. While natural stone floors in churches often last for centuries, it can be assumed that the carpets in office buildings nowadays will be replaced every ten years on average [149]. This is only partly due to the material’s durability. Residential and office buildings, and especially shops and similar spaces often change tenants and are subject to the whims of fashion, so it is all the more important to use recyclable materials and lay them to be detachable or floating. The adhesives in floor coverings and screeds often prevent these materials from being recycled for use in a higher-quality product. Instead of choosing the usual glued tile or artificial stone floors for wet areas, floors that can be easily detached (e.g. made with

B 2.32 Mastic asphalt heating screed: combined with copper pipes, an urban-mining-compatible building component B 2.33 Material Cycle Status: floor substructures MRC = Material Recycling Content MLP = Material Loop Potential MEoL = Material End of Life (see also sample graphic, Fig. B 2.4 a, p. 64) B 2.34 Material Cycle Status: floors and ceilings: ­surfaces MRC = Material Recycling Content MLP = Material Loop Potential MEoL = Material End of Life (see also sample graphic, Fig. B 2.4 a, p. 64)

Mineral materials

Fossil-based material

Biotic material

The Recycling Potential of Building Materials

Material Floor substructures

Thermal conductivity [W/(m K)]

Vapour diffusion ­resistance factor [µ]

Fire behaviour [DIN EN 13 501-1]

Lifetime

OSB panel  *) from prorated sustainable forest ­management E1

0.13

200/300

Dfl-s1-E 1)

> 50 2)

Mastic asphalt screed 3)

0.7

50 000

Bfl-s1

> 50 4)

Plasterboard

0.25

10/4

A2-s1

> 50 2)

Screed tile  *)

0.67

200/120,000 5)

A1

> 50 2)

Material Cycle Status

Additional recycling potential

0 %   20 %   40 %    60 %   80 %   100 %

MRC MLP MEoL MRC MLP MEoL

MRC MLP MEoL MRC MLP MEoL

For additional panel materials from biotic sources see Fig. B 2.29 (p. 82) *) The data are supplied by the manufacturer; they refer to select products and are not applicable to the entire product category. The published table entries are reference values that may differ significantly from those of individual cases.  1) depending on bulk specific gravity, application and thickness  2) as dry screed  3) MEoL: Assumed values based on the recycling rates of the road construction waste fraction.  4) as visible surface  5) unglazed /glazed B 2.33 Material Floor, ceiling: Surfaces

Fire behaviour [DIN EN 13 501-1]

Lifetime

Solid timber planks

Dfl-s1-Cfl-s1 1)

> 50

      Material Cycle Status

0 %   20 %   40 %    60 %   80 %   100 %

Fossil-based material

Biotic materials

MRC MLP MEoL Multilayered parquet

Dfl-s1-Cfl-s1 2)

40

Linoleum  *)

Cfl-s1

10

Nylon carpet tile  *)

Bfl-s1 3)

10

Additional recycling potential

MRC MLP MEoL

MRC MLP MEoL

MRC MLP MEoL

Wiederverw

Wiederverw Wiederverw

Wiederverw Weiterverw

Weiterverw Weiterverw

Weiterverw Herstellerrü

Herstellerrü Kompostie

Kompostie *) Data supplied by the manufacturer; they refer to select products and are not applicable to the entire product category. The published table entries are reference values that may Energetisch differ significantly from those of individual cases.  1) depending on wood type and thickness. Cfl-s1 is achieved by solid timber floors of oak (> 650 kg/m3), beech (> 680 kg/m3) 3 2) or spruce (> 450 kg/m ).  depending on wood type and thickness. Cfl-s1 is achieved in multilayered parquet floors with a wearing layer of oak when they are installed with a thickness of more than 20 mm.  3) tested in unglued state Energetisch B 2.34

85

a

b

glass materials) should be considered (see “Detailed Catalogue”, Example 09, p. 175ff.).

Linoleum The name linoleum, containing as it does the Latin words “linum” (linseed) and “oleum” (oil), refers to the linseed oil which, with powdered cork and jute fabric, is one of the main basic mate­rials of linoleum. Linoleum is made by ­mixing linseed oil (approx. 19 %) and tall oil (a by-product of the pulping process, approx. 11 %) with natural resin (approx. 2 %), which reacts to form a material called linoleum cement. Other filler materials are then added to the ­linoleum cement. To improve its colour durability and resistance to fading, a typical product will nowadays contain powdered cork or ­sawdust (approx. 22 %), as well as calcium carbonate (ca. 24 %), recycled linoleum ­(usually a maximum of 10 %), titanium dioxide and pigments (approx. 3 %) [150]. The mixture is then applied to jute backing material (approx. 8 %). Although linoleum does not need any ­surface coating, almost all linoleum currently available unfortunately has a poly­ urethane surface finish. Linoleum is free of PVC, plasticisers, solvents and synthetic rubber. It is extremely robust and hard-wearing (suitable for wheelchairs) as well as hygienic. The material’s antistatic and bacteriostatic properties mean that it does not need any chemical additives and guarantee that it poses no health risk [151]. Linoleum can also be laid loose in the form of tiles or on a base plate (see “Click-lock linoleum floor panels”, p. 53) as an alternative to other floor covering sheeting that is fixed with adhesives.

only limited suitability for workspaces because these carpets are ­suitable for gliding chairs but not for chairs on castors. Carpet can be edged with a felt, leather or linen binding. Some carpets can be fitted loose and fastened at the edges (with carpet tape) or fixed with Velcro (see “Fitted carpets”, p. 54). Pure, untreated sisal can be recycled as a mater­ial in the form of composting at the end of its life, but other carpets are generally only used in energy generation.

Sisal, coconut fibre and animal hair carpets Natural, renewable materials such as sisal (from the agave plant), coconut fibre and animal hair are very good for making woven carpets. Carpets that do not need backing are preferable because other types of materials are often used to make a backing that is inseparably bonded to the surface, making the carpets harder to recycle. Planners should also check whether natural fibres have been treated (with flame retardant or an antistatic agent). If backing is necessary, 100 % cotton is preferable to a material from another group (e.g. latex). The vast majority of natural fibre woven carpet is of

The many demands made on insulating mate­r­ ials in recent decades have resulted in the development of products with a wide range of structural physical characteristics that are specifically tailored to fit in with their applications (Figs. B 2.37 and B 2.42, p. 91). Once an insulating material is installed, it is usually very hard or impossible to access and repair or retrofitting are hardly possible. Replacing insulation involves comprehensive construction measures, so the quality and durability of these materials and their continuous effective performance over the building’s entire life cycle is crucial. Building biology

Biotic Materials Floor coverings made of plant and animalbased materials vary greatly in terms of their potential applications, durability and ease of maintenance, but they all have one thing in common: natural materials always create a cosy, high-value spatial impression that cannot be achieved with cheaper artificial materials (e.g. laminate). Solid wood and wood-based materials Timber floors are more robust than is widely assumed and, with surface coatings such as soap or oil, can be eminently suitable for hightraffic public areas, as countless schools and museum buildings in Austria and Switzerland show – even without painting and varnishing, which can impede recycling. Such floors can also achieve good fire protection values, depending on the type of timber and thickness of the material used. Solid wood floor coverings with a surface coating of a density greater than 390 kg/m3 (with or without an air gap underneath them) are normally classified in fire protection class Dfl-s1 (“of normal flammability”). They were formerly classified as being “of low flammability”. Solid wood floors made of oak (> 650 kg/m3), beech (> 680 kg/m3) and spruce (> 450 kg/m3) and multilayered parquet floors with an oak surface that are more than 20 mm thick are all classified in class ­Cfl-s1. The “Holzforschung.at” timber website offers a good summary of the fire protection classi­ fications of wood and timber products.

B 2.35 Synthetic carpet recycling: manufacturers agree to take back and recycle the material. a Shredded old carpets from manufacturer take-back programme b Yarn made from waste material B 2.36 Wood shavings insulation can be perfectly compacted in factory prefabrication B 2.37 Application areas of thermal insulation in accordance with DIN 4108-10

86

B 2.35

Fossil-based materials: nylon carpet tiles

A Dutch manufacturer produces carpet tiles suitable for chairs on castors with a surface layer that is made entirely of reclaimed nylon from recycled waste (e.g. fishing nets and used waste yarn / post-consumer material) (Fig. B 2.35). The tiles’ backing is also made of at least 70 % recycled material, namely calcium carbonate (lime), a by-product from the drinking water industry. They have been positively rated in the Cradle-to-Cradle system (see “The material cycle concept in the Cradle-to-Cradle system”, p. 29) These carpet tiles are self-laying and sufficiently fixed by their own weight. They can be completely recycled to make an equivalent product, so the manufacturer has established a programme for taking back its own products and recycling them in the company’s reprocessing plant [152]. Insulation

The Recycling Potential of Building Materials

B 2.36

aspects, environmental sustainability and possible recycling are further important parameters to consider when choosing insulation. All products made of synthetic materials and / or heavily treated currently end up being used to generate energy, which can, however, entail unforeseen, wide-ranging difficulties, such as those resulting from the addition of the flame retardant hexabromocyclododecane (HBCD) in polystyrene in the past. After HBCD, which is a persistent organic pollutant (POP), was declared to be a hazardous substance requiring special waste treatment, sales declined steeply and there were then large-scale bottlenecks in its disposal, so the German government retracted its hazardous substance classification. Waste containing HBCD must, however, now be separately collected and its disposal documented (see “The costs and profit of dismantling”, p. 122f.) [153]. In the foreseeable future, it will be possible to recycle EPS and XPS waste (open- and closedcell polystyrene foam) as material, as long as it can be strictly separated from its bond with the substratum. In the Netherlands, there is already a stationary pilot plant that is able to recover primary styrene acrylate in high quality from waste and to reprocess it again to make insulating materials. The bromine from the flame retardant that the waste contains is also recycled and the rest disposed of in an incinerator. Initial tests carried out in cooperation with insulating materials manufacturers have shown that 30 % recyclate can be added without affecting the end product’s quality. The very low cost of insulating materials and the resulting transport and energy costs for recycling make their assignment questionable for economical and ecological reasons, as long as recycling facilities are not widely available [154]. Oil-based insulating materials (or those that have been intensely treated) will therefore not be ­further discussed here. Insulating materials that are inexpensive to ­procure will probably not be reused, even though bulk materials and blown-in insulation could theoretically be partly recovered by means of vacuuming, but this is not econom­ ically viable.

Biotic materials

Insulating materials made of natural biotic materials offer ecological advantages [155] although, according to the figures currently available (for 2011), the market share of insulating materials made of renewable raw materials in Germany is only 7 % [156]. Natural products and those not treated with chemical but with natural additives can be composted at the end of their useful lives. The German Bio-Waste Ordinance (Bioabfallver­ ordnung – BioAbfV) classifies biodegradable products made of renewable raw materials without additives or contaminants as recyclable biowaste products suitable for use on land. A current lack of logistics for compostable construction waste means that it can be assumed that waste materials from demolitions will continue to be used in energy generation [157].

Ecologically friendly insulating materials are easier to process and do not usually contain pollutants that can be released into the interior air, although they are often treated with additives to protect them from fire, moisture or pests. In the interest of possible subsequent composting, products that do not depend on the addition of biocides, formaldehydes or borates are preferable [158]. Wood-fibre insulation board Wood-fibre insulation boards are produced using either a wet or a dry process. The wood used to produce them should preferably be waste or by-products from the sawmill industry. The wood’s own lignin is used as the bonding agent in the wet process, which results in a pure product without additives. The use of water and heat does, however, consume up to

Application area

Abbreviation 1)

Description

Roof, floor / ceiling

DAD

Exterior insulation of roof or floor, protected from weather exposure, insulation under coverings Exterior insulation of roof or floor, protected from weather exposure, insulation under sealing sheets Exterior roof insulation, exposed to weathering (inverted roof) 2) Insulation between rafters, ventilated roof, uppermost floors can be ­accessed but not walked on Interior insulation of the underside of the floor or the roof, insulation under the rafters / support structure, suspended ceiling, etc. Interior insulation of the floor or ground slab, upper side under the screed with no sound insulation requirement Interior insulation of the floor or ground slab, upper side under the screed with sound insulation requirement

DAA DUK DZ DI DEO DES Wall

WAB 2) WAA WAP 2) 3) WZ WH WI WTH WTR

Outer insulation of the wall, behind cladding Outer insulation of the wall, behind sealing layer Outer insulation of the wall, under plaster 3) Insulation of double-leaf walls, core insulation Insulation in timber frame and timber panel construction Inner insulation of the wall Insulation in house separation walls with sound insulation requirements Insulation of partition walls

Perimeter

PW

Thermal insulation on the exterior of walls with ground contact (outside the sealing layer) 4) Thermal insulation on the exterior of the ground slab with ground contact (outside the sealing layer) 4)

PB 1) 2) 3)

The abbreviations used are for German descriptions of application areas for thermal insulation. Applies to cases where floor undersides are exposed to outside air The application/abbreviation WAP does not apply to insulation panels in composite thermal insulation systems. The use of composite thermal insulation systems is not standard.  4) Subject to the specifications of DIN 4108-2. B 2.37

87

B 2.38

B 2.39

40 % more energy per tonne than dry processing. Dry ­processing does not require water, but requires an additional bonding agent, which means that the board no longer consists of a single mater­ial and limits its prospects of recycling or future composting. The maximum board thickness that can be feasibly achieved using the wet process is limited to 40 mm. Thicker boards must be glued with an additional bonding agent or installed in several ­layers that are attached mechanically. Singlelayer insulation boards with a homogeneous raw density profile up to 240 mm can, however, be produced using a dry process [159]. Wood-fibre insulation board is vapour-perme­ able so it can be used to make vapour-perme­ able structures. The board’s marked capacity for absorption and desorption, which is typical of wood and enables it to absorb up to 20 % of moisture by weight without damage, can be particularly advantageous. Wood-fibre insulation board can be used in interiors and for ­exterior areas with added structural protection, as insulation or as impact sound insulation. There is currently a product on the market that is produced without any bonding agents or other additives and consists entirely of sawmill waste. Wood-fibre insulation cannot be fed back into the wet production process, because lignin only bonds once after being heated and the process cannot be reversed. Pure products will be able to be composted in future, although for practical reasons they currently usually end up in energy generation [160].

One alternative form of impregnation is a very thin film of clay loam coating, which protects the insulation from fire and organic infestations. Other options for improving its fire protection properties are currently not yet pollutant-free, so they will not be described here. This insulating material can be blown in, manually installed by pouring in, filling or packing. ­During the prefabrication of wall or ceiling structural components, the components can be precisely horizontally filled with the shavings or chips and the filling optimally compacted in the factory.

Blown-in, poured-in or packed-in wood particle insulation A wood shaving insulation is currently available on the market that uses only natural wood shavings or chips (Fig. B 2.36, p. 87), prefer­ ably by-products from the local sawmill industry that are treated with whey (a natural by-product of cheese production) to improve its fire safety properties. Adding soda (sodium carbonate) increases its resistance to fungal infestation. This kind of impregnation is durable and does not have to be renewed when the product is ­reused. Since 2013, this insulation has had a Gold Standard Cradle-to-Cradle certificate [161]. 88

Cork insulating panels or granulate fill Cork is made from the bark of the cork oak, which grows mainly in Portugal and the Mediterranean. It has very good heat retention properties and is relatively resistant to moisture (and to rotting and decay). The material’s mass gives it positive soundproofing properties, it retains its form and elasticity well, is resistant to insects and fungus and is unattractive to rodents [162]. A distinction is made between pure and compound or composite agglomerated cork. Pure cork is preferable because an artificial bonding agent is required to produce compound or composite agglomerated cork. Pure agglomerated cork is made by subjecting ground cork granulate to heating and steam in a mould to form a block (Fig. B 2.40). The cork’s own resin functions as a bonding agent. Scrap from production is processed into re-granulate and used in cavities as insulating cork granulate fill – a high-quality reuse of the material, for which cork board can also be used after careful separation and dismantling [163]. Reused bottle corks can also be upcycled by cleaning them from impurities and grinding them into granulate for use as bulk filling material. This material does not require further additives [164]. Cellulose flake insulating fill or blown-in ­insulation The basic material used to make cellulose insulating material is waste paper from newspapers (at least 80 %). Halogenated bleaching chemicals and ethylenediaminetetraacetic acid (EDTA) should not be used in the processing. 8 to 15 % boric salt is usually added to the

waste paper to protect it from fire and pests [165]. The trace element boron occurs naturally but is also classified as an SVHC [166]. SVHCs, “Substances of Very High Concern”, are chem­ ical compounds that the European chemicals regulator REACH has identified as having particularly dangerous properties (e.g. as toxic to reproduction) [167]. A borate-free alternative with additives based on mineral sulphate is preferable from a building biology perspective. Cellulose fibres are vapour-diffusive, balance ambient moisture and are sound-absorbing as well as being quick to process and inexpensive. Cellulose flakes are suitable for insulating cavities and are poured into structures or blown in under pressure and can be used to fill irregularly shaped cavities without joints. These kinds of insulating materials can, however, subside over time, especially if exposed to moisture, which can result in thermal bridges [168]. Hemp fibre insulating panels, felt or wool Hemp straw is retted to separate it into fibres and shives. The fibres can be made into insulating mats, felt or insulation fill, while the woody shives are made into loose insulating fill or solid panels. Hemp fibres are extremely tear-proof and moisture-resistant and can retain up to a third of their own weight in moisture and dry out again without impairing the material’s thermal insulating properties. Bitter compounds in the plant make hemp naturally resistant to rotting, pests, rodents and mould [169]. Since hemp fibres do not contain protein, they are also resistant to decay processes. One German manufacturer uses support fibres based on polylactide (PLA) to maintain the dimensional stability of its mats and sheeting, which unlike ordinary hemp insulation with synthetic support fibres, can be composted at the end of its useful life [170]. Compared with flax insulation, which is mainly treated with boric salts as a fire retardant, structurally and bio­ logically safe soda is used and the manufacturer guarantees that the material can be returned once it has been carefully separated out after dismantling. The product can be

The Recycling Potential of Building Materials

­ e-fibred in a shredder and reused or recycled d in production, although there is currently little demand for it. Alternatively, the de-fibred mater­ ial can be reused as filling wool. In Germany, controlled cultivation of some low-narcotic hemp varieties has only been allowed since 1996, so no large quantities of hemp insulating materials are currently becoming available from dismantling. Jute fibre insulating panels, felt or wool The basic material of one form of jute insulation available on the market comes in the form of used cocoa or coffee sacks, which are reused and made into insulating mats, felt or wool (Fig. B 2.38). They are cut up and their fibres cleaned with soda and treated with fire retardant. PLA-based support fibres are added and they are then made into a non-woven material. This product is regarded as non-toxic, poses no risk to health and is biodegradable [171]. Jute is ­naturally resistant to mould and insects and its ability to absorb moisture helps create a healthy interior climate. Clean jute insulation can be used in a closed materials cycle, composted and reused as filling material. Moreover, the product’s manufacturer will take back pure material [172]. Not all jute insulating materials are, however, upcycled materials, so planners must check with manufacturers whether this is the case. Primary jute material (a collective term for the bast fibres of various Corchorus plants) can also be used (see “Jute fabric”, p. 83) to make this insulation, although its transport costs are very high. Coconut fibre insulating panels, felt or wool Coconut fibre insulating material is made by subjecting coconut shells to a decay process that causes all substances susceptible to rot to break down. The fibres are then made into panels, mats or felt and impregnated with 1.5 – 7 % boric salts or ammonium sulphate as a fire retardant. Here too, borate-free ­products are preferable. It is the bonding of cellulose and lignin that gives coconut fibre elements their good compressive and tensile strength. The fibres are flexible and resistant to tearing and pressure. Their hollow cross-

B 2.40

B 2.41

section ensures high levels of permeability to vapour and they can absorb and rapidly release up to 100 % of their own weight in ­moisture, which prevents mould from forming in rear-ventilated structures. Coconut palms grow in equatorial regions and are usually not fertilised or treated with pesticides. If, however, they are grown in monoculture plantations, as is often the case, and natural forest is cleared to make way for plantations, the biotic cycle is broken. Mechanically undamaged, clean fibres can be fed back into the production process for recycling, which is, however, currently not done due to the add­ itional transport costs. Pure coconut fibre can be reused as packaging material before ending up in energy generation [173].

that of comparable biotic insulating materials. Seagrass does not contain protein, so this type of insulation does not rot. Its fibres can absorb and release humidity without diminishing its thermal insulation properties. The insulation is delivered as a loose wool in sacks, for which there is a deposit system. At the end of its ­useful life, it is used in energy generation. The manufacturer will take back insulating material once it has been carefully separated out after dismantling [175].

Reed insulating mats Dried reed is made into mats without chemical additives or bonding agents by compressing individual reeds and binding them by machine with galvanised wire. Biodegradable alternatives to the wire are currently being developed. Plastered with loam or clay, due to their airfilled centres, reed insulating mats have the advantage of combining thermal insulation and a base for plaster in one product. They are very stable yet malleable and therefore suitable for making curved surfaces. The dry insulation mats are also resistant to fungus and pests. They are attached to masonry or other substrata with insulation fixings or screwed onto wooden boards. If it does not contain any additives, the reed can be composted after being separated from the metal [174]. Seagrass insulation for blowing or pouring in Seagrass balls made of fibres of Posidonia oceanica often wash up on Mediterranean beaches (Fig. B 2.39). A manufacturer has them gathered, dried in the sun, shipped to Germany and made into insulation. The seagrass balls are frayed out to produce a homogeneous wool that is processed without any further additives into insulation for blowing or pouring in or insulating wool filling. Despite the cost and effort involved in its transport, the primary energy expended in the entire procurement and production process can be lower than

New sheep’s wool insulating felt A permanently regenerating by-product of the meat industry, new sheep’s wool also has ­positive characteristics as an insulating mater­ ial, as long as forests are not cleared to create more grazing land for the sheep. The wool is washed with a curd soap and soda to free it of excess lanolin and dirt. The protection from moths and beetles that it needs is often provided by sodium borate, although this ­protection becomes ineffective over time and must be renewed. Mitin FF (Sulcofuron) and Thorlan IW moth repellents are another option, although they are not currently approved for use in Europe. In Germany, permethrin is also sometimes used, although the German Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung – BfR) classifies it as a neurotoxin, so this treatment is very contro­ versial. One Austrian manufacturer currently makes a sheep’s wool insulating material with a biocide- and borate-free moth repellent that poses no risk to health, by modifying the wool fibres’ surface with an electrophysical procedure that protects it permanently. The wool is then mechanically needled without any add­ itional bonding agent to make insulating fleece, felt and mats (Fig. B 2.41). Insulating wool is delivered to building sites in foil bags (with a

B 2.38 Jute insulation: upcycling used coffee sacks B 2.39 Seagrass insulation: found and collected on beaches B 2.40 Rot-resistant cork installed as impact insulation under the screed B 2.41 New sheep’s wool used as sound insulation in drywalls

89

deposit system). The manufacturer takes back carefully separated material and feeds it back into the production cycle. Scrap material can also be reused as wool filling or to make joint tape. Wool that has been soaked in water can be processed into rolls of insulating material once it is dry. New sheep’s wool is a particularly suitable insulating material in timber structures because it adjusts well to wood’s shrinkage, swelling or warping and it can absorb up to one third of its own weight in moisture without losing much of its insulating effect. It also has very good sound-proofing properties and helps to purify the air as well as regulate moisture. Sheep’s wool insulation has a high combustion point compared with other natural fibres. It only ignites at 560 °C, so it does not have to be treated with any additional fire retardant that would emit gases in the event of fire or could impede its recycling [176]. Mineral materials

Mineral insulating materials have one compelling unique property: they are not flammable. Their uses at the end of their useful lives vary greatly, ranging from recycling into a product of the same quality through to disposal in landfill. Expanded clay insulating fill The basic material in expanded clay is expandable clay that is extracted from opencast mines and, after months of storage and drying, expanded in a rotary kiln and fired at approx. 1,200 °C. This firing burns up the organic constituents in the clay, leaving fine pores in the grain. Expanded clay does not rot or burn, is durable, can bear loads, is resistant to frost and vapour-permeable. It has greater density than other insulating materials, so expanded clay is very suitable for soundproofing and storing heat, although its thermal insulation properties are not quite as convincing. Expanded clay can theoretically be completely reused but it rarely is, due to a lack of demand and high transport costs [177]. Mineral fibre insulating mats Insulation made of artificial mineral fibres such as glass and mineral wool is widely used in 90

Germany, at rates of over 50 % [178]. The basic materials used to make glass wool include waste glass (50 – 70 % on average from production waste), sand, lime, clay and alkaline compounds, usually bonded with 5 –7 % formaldehyde resin. Mineral wool is made from rock (dolomite, ­diabase, basalt, limestone) and an average of 45 – 60 % cement-bonded waste material (fibres from production scrap and ash) and is usually bonded with 1– 3.5 % formaldehyde resin [179]. From a structural and biological perspective, it is preferable to choose a mineral wool of the type currently available on the market that contains a formaldehyde-free bonding agent [180]. Earlier products contained fibres that could damage health (being respirable and carcinogenic) and planners should still examine the criteria that exempt a product from classification as a carcinogen in its product safety data sheet, which verify its innocuousness [181]. Tests have shown that glass wool could be made of 100 % waste using recycled glass as the basic material [182]. It is difficult to recycle artificial mineral fibres by melting them down. Materials from composite thermal insulation systems that adhere to them and the formaldehyde-phenol resin the product contains impede recycling and make it uneconomical. Microwave technology still ­currently at the research stage may make it possible to process the material into slag and recycle it as a raw material to make mineral wool insulation in future. Since 1993, one German manufacturer has taken back pure waste products from its own production for a fee when new products are purchased. Artificial mineral fibres are, however, generally not reused at the end of their useful lives but disposed of in class I or II landfill [183]. Foam glass insulating panels Foam glass panels are currently made from up to around 70 % recycled glass. The glass is melted down and, after cooling, is ground into powder and foamed with the addition of carbon at 850 °C. This creates a closed cell structure that is not permeable to gas, with pores containing 99 % carbon dioxide, 0.7 % hydrogen

sulphide and 0.3 % nitrogen. These gases make up approx. 95 % of the insulation [184]. The panels are made in moulds, in which the molten foam glass mass is cooled in a controlled manner to be stress-free. The foam glass blocks are then cut into panels. The resulting insulating material is resistant to ­moisture and frost, non-flammable and resists pests. Furthermore, it does not rot and can bear compressive loads [185]. Insulating panels are usually glued to their ­substratum using hot bitumen or cold adhesives over their entire surface, which makes them almost impossible to recycle. Only loose or mechanical mounting guarantees that the materials can be separated out after dismant­ ling (see “Dismantling, Recovery and Disposal in Construction”, p. 16ff.). Insulating foam glass gravel Foam glass gravel is made in a similar way to foam glass panels, although it can be made of 100 % waste material [186]. The molten foam glass mass is cooled quickly so that stress cracks form, causing it to crumble into granular chunks. It is especially useful in construction as a load-bearing and anti-capillary layer under foundations and cellar and base plates, where it takes on drainage as well as thermal insulation functions. Its thermal insulation properties decline when it is exposed to pressure from water, which must be counteracted with a thicker layer of insulation. A ­system enabling vertical perimeter insulation materials to be disassembled is currently ­available (see “Perimeter insulation of a cellar wall”, p. 47) [187]. At the end of their useful lives, the material in both foam glass products, the gravel and the panels can be recycled after being disassembled, carefully separated and recovered without the adhesion of other materials. The mater­ ial is ground up and fed back into foam glass production or reused as filler and bulk filling material. B 2.42 Material Cycle Status: Insulation MRC = Material Recycling Content MLP = Material Loop Potential MEoL = Material End of Life (see also sample graphic Fig. B 2.4 a, p. 64)

Wiederve

The Recycling Potential of Building MaterialsWiederve Wiederve

Mineral materials

Fossilbased material

Biotic materials

Weiterve Wiederve

Additional Weiterve recycling Weiterve potential

Material Insulation

Application area Abbreviation [in accordance with DIN 4108-10]

Thermal conduc­t­ ivity [W/(m K)]

Bulk specific gravity [kg/dm3]

Vapour diffusion resistance factor [µ]

Lifetime Material classification [DIN EN 13 501-1]

Material Cycle Status

Fibreboard insulation (lignin-bonded)  *)

DAD, DZ, DI, DEO, WH, WTR

0.04

0.16

5

E

0 %   20 %    40 %    60 %   80 %   100 %

> 50 MRC MLP MEoL

Herstelle Weiterve

Kompost Herstelle Wiederve

Wood shavings ­insulation with soda and whey  *)

DZ, DI, WH

0.049

0.07

2

E

30

MRC MLP MEoL

Energetis Kompost Wiederve Wiederve

Cork insulating panels  *)

DAD, DAA, DZ, DI, DEO, WAB, WAP, WZ, WH, WI, WTR

0.037

0.11

5 –10

E

> 50

MRC MLP MEoL

Energetis Weiterve Wiederve

Cork granulate  *)

DZ, DEO, DES, WH, WI

0.045

0.125

5 –10 1)

E

> 50 2)

Cellulose flakes, borate-free  *)

DAD, DZ, DI, WH, WI, WTR

0.039 – 0.042 3)

0.03 – 0.06

Hemp fibre matting with PLA reinforcing fibres  *)

DAD, DZ, DI, WAB, WH, WI, WTH, WTR

0.04

Jute fibre matting with PLA reinforcing fibres  *)

DZ, DI, WAB, WH, WI, WTR

0.038

Coconut fibre insulation

DZ, DI, WH, WI, WTR

0.045 –  0.05

0.05 – 0.14

1– 2

E

50

Reed insulating matting

DI, DEO, DES, WAB, WAP, WI

0.061

0.19 – 0.225

1– 2

E

20 – 30

Seagrass wool  *)

DZ,DI, DEO, DES, WH, WI, WTR

0.039

0.065 – 0.075 1– 2

E

> 50

Sheep’s wool  *)

DZ, DI, DEO, WH, WI, WTR

0.039

0.018

E s1, d0

> 50

2

B ­s2 d0 4)

50

0.028 – 0.046 1– 2

E

50

0.034 – 0.04

E

50

1– 2

1

MRC MLP MEoL MRC MLP MEoL MRC MLP MEoL

MRC MLP MEoL MRC MLP MEoL MRC MLP MEoL MRC MLP MEoL MRC MLP MEoL

Wiederve Wiederve Weiterve Weiterve

Wiederve Wiederve Herstelle Weiterve Wiederve Weiterve Weiterve Kompost Herstelle Wiederve Weiterve Weiterve Wiederve Energetis Kompost Weiterve Herstelle Herstelle Wiederve Energetis Weiterve Kompost Kompost Weiterve

Wiederve Wiederve Herstelle Energetis Energetis Weiterve Wiederve Wiederve Kompost

Herstelle Wiederve Weiterve Weiterve Energetis

Kompost Wiederve Weiterve Weiterve

Energetis Weiterve Herstelle Herstelle

Weiterve Kompost Kompost

Herstelle Energetis Energetis

Expanded polystyrene DAD, DAA, DZ, DI, (EPS) foam DEO, DES, WAB, WAP, WAA, WZ, WI

0.035 –  0.045

0.015 – 0.03

20 –100

E

50

MRC MLP MEoL

Expanded clay

DEO, DES

0.1 – 0.16

0.3 – 0.8

3

A1

> 50

MRC MLP MEoL

Energetis Wiederve

Foam glass insulating panels

DAD, DAA, DI, DEO, 0.038 –  0.042 WAB, WAA, WAP, WZ, WI, WTR, PW, PB

0.1 – 0.12

infinite

A1

> 50 5)

MRC MLP MEoL

Wiederve

Foam glass gravel  *)

PW, PB

0.16 – 0.19

2– 4

A1

> 50

MRC MLP MEoL

Fibreglass (AMF)  *)

DZ, WH, WI

0.103

0.035

0.018 – 0.021 1

A1

50

MRC MLP MEoL

Kompost

Weiterve

Wiederve Weiterve

Wiederve Herstelle

Weiterve

*) Data supplied by the manufacturer; they refer to select products and are not applicable to the entire product category. Kompost The published table entries are reference values that may differ significantly from those of individual cases.  1) no manufacturer-supplied data, assumed value based on unused cork  2) matched to cork panel value  3) 0.039 W/(m K) for blow-in insulation, 0.042 W/(m K) for sprayed  4) for installation of 40 –100 mm, > 100 mm  5) comparable to foam Weiterve glass gravel B 2.42Energetis

Herstelle 91

Kompost

Seals and Separating Layers Seals for protecting structures from moisture and wind or separating layers are usually ­“hidden” in layers of structural components and not visible from the outside. As with insu­ lation, once the material has been installed, it cannot be easily or quickly replaced or repaired. Seals, separating layers and vapour barriers meet very different demands, so the range of materials available for making them varies accordingly. Adhesion to substrata and the multilayered nature of products themselves often make it difficult to carefully separate out, disassemble and recycle them. To improve their mechanical properties, bitumen or synthetic seals, for example, often contain glass fabric, polyester or fibreglass backing layers and their surfaces are covered with plastic granulate or mineral materials. This mixture of mate­rials makes them harder to recycle, so homo­geneous seals and separating layers made of just one material are preferable to ­multilayered products. Sealing sheeting and separating layers made of soft PVC (PVC-P) are not recommendable in the interests of pollutant-free construction, so they will not be further considered here (see “Recycling potential of fossil-based materials”, p. 61f.). If they have to be disposed of after reconstruction or demolition, there is a crossvendor system called “Roofcollect” that is

B 2.43

92

­ perating in many European countries and o takes back these materials. The recycling ­process produces mainly plastic granulate. Biotic materials

Synthetics-based separating layers are the norm, but equivalent separating layers made of plant- or animal-based materials are preferable for ecological reasons. One unusual form of sealing, a roof sealing membrane containing a significant proportion of renewable raw materials, is described below. Greyboard separating layers or as trickle pro­ tection Greyboard can be used as a separating layer under mastic asphalt screed, as a covering sheet (e.g. to protect a freshly laid stone floor), as trickle protection under loose filling, or as a separating layer under parquetry flooring. This renewable and recyclable raw material can often be used instead of plastic sheeting. Greyboard is vapour-permeable, dampens sound, is absorbent and can be made entirely out of waste cellulose. Greyboard that has been carefully separated after dismantling can be theor­ etically fed back into cellulose recycling. The adhesion of other materials can, however, prevent the recovery of pure greyboard separating layers, so it usually ends up being used for energy gener­ation [188]. Kraft paper trickle protection Kraft paper, which is made of the cellulose fibres of long-fibre conifer wood (e.g. pine and spruce), is eminently suitable for use as trickle protection and characterised by its strength and durability [189]. Kraft paper carefully separated after dismantling can be reused as paper padding in protective packaging, for example, before it is used in energy generation at the end of its cascading utilisation [190]. Windproofing made of new sheep’s wool on kraft paper To make dimensionally stable and vapour-­ permeable windproofing, new sheep’s wool is glued to kraft paper with an organic glue (Fig. B 2.43), a water-based, solvent-free, dispersion wet-contact adhesive. The ecological

and fire protection advantages of new sheep’s wool have been described above in the section on “New sheep’s wool insulating felt” (p. 89f.). The windproofing sheets are stapled onto a substratum, overlapping. Windproofing paper can be further used in energy generation [191]. Plant-based roof sealing sheeting One alternative to oil-based sealing materials is a type of bitumen-free and halogen-free flat roof sealing sheeting made of renewable, plantbased raw materials that is currently available on the market. The sheets are made of 50 – 60 % plant oils and pine resin (waste from biopolymer manufacture and the paper industry) as well as styrene-butadiene-styrene (SBS) and mineral fillers. To improve its strength, elasticity and tear resistance, the sheeting is reinforced with a combination polyester and glass-fibrefleece backing and reinforcement layer. A white acrylic coating on the sheeting’s surface prevents the roof and surrounding area from overheating in summer. This sealing sheeting has been awarded a bronze Cradle-to-Cradle certificate. It is suitable for new buildings and renovations and is fused onto its underlay over its entire surface. The manufacturer, however, recommends gluing the underlay, which is also plantbased, bitumen-free, halogen-free and reinforced with a polyester and glass fibre fleece, to the substratum over its entire surface. This multilayered structure would seem to make recycling or downcycling difficult. The sheeting’s Belgian manufacturer has, however, stated that they are working on a process that will make it possible in future to take back this entire roof sealing system, separate it out into its various components and return it to the ­production cycle [192]. Metallic materials: aluminium vapour barriers

One positive property of metals is that they are not vapour-permeable, which makes aluminium suitable for use as a vapour barrier. 0.05-mmthick sheets made entirely of aluminium are joined with an adhesive tape containing a high proportion of aluminium and a synthetic adhesive. The adhesive can be separated from the aluminium for recycling.

The Recycling Potential of Building Materials

B 2.44

This product’s recycling potential compensates for the negative environmental impact of the aluminium production. To avoid unfavourable effects from any impurities in the ­secondary aluminium, the manufacturer uses 100 % primary aluminium to make this vapour barrier [193]. Fossil-based materials

It is currently hard to imagine sealing buildings without bitumen and plastics. Here, as so often, loose installation and the use of products made of single materials determine the quality of any subsequent recycling. PE-HD deck underlay, housewrap and facade facing sheeting One product on the market is made of over 99 % high-density polyethylene (PE HD) and UV ­stabilisers (less than 1 %) and is suitable for use on a roof or facade, as deck underlay, housewrap, facade facing sheeting or windproofing. This sheeting has various advantages, being vapour-permeable yet wind- and rain-proof, highly tear-resistant and very light (around 0.2 mm thick). It is laid in a ­single layer directly onto rafters, studs, formwork boards or on ­insulation over rafters. The product is single-­ layered, so without lamination or reinforcing ­layers made of other materials, which would seem to make recycling possible. According to the product’s environmental product declaration (EPD), however, it should be used in energy generation at the end of its life [194]. PE-LD vapour barriers One vapour barrier available on the market for use in ceilings, roofs or walls is made of 100 % low-density polyethylene (PE-LD). It is tear-resistant, durable and inhibits water vapour diffusion (sd value of >100 m with a thickness of 0.2 mm). Joints in the foil are given an airtight seal with adhesive tape and it is fixed onto battens. Since the product is made of a single material it should be possible to reuse this plastic [195]. Bitumen sealing sheeting Standard commercially available bitumen sheeting can be processed in suitable plants to make new bitumen sheeting after separ­

ation and dismantling. It must be ensured that plastomer bitumen sheeting containing atactic polypropylene (APP), which is used mainly in the Benelux countries, is collected separ­ ately from elastomer bitumen sheeting con­ taining styrene-butadiene-styrene (SBS; see “Plant-based roof sealing sheeting”, p. 92). A Belgian manufacturer uses around 30 % ­production waste and scrap material from building sites in his APP-bitumen sheeting and has set up a system for taking back waste material [196]. Its high calorific value means that bitumen sheeting is currently still mainly further used in energy generation. The declining availability and increasing price of bitumen will, however, probably result in positive changes to this ­situation in future [197]. Bitumen sheeting is not currently recommended for greened roofs, because root-proof sheeting is either treated with biocides or equipped with a metal inlay, which is questionable from an ecological point of view and can make it hard to recycle. Multilayered plastic cellar sealing For a vapour-permeable tank solution that protects against exterior pressure from water as prescribed in DIN 18 195-6, there is a three-­ layered cellar sealing system on the market that works without adhesion to a substratum (Fig. B 2.44; see also “Loosely laid cellar sealing system”, p. 47). Originally designed to seal base plates in industrial structures (petrol stations), it consists of a dimpled air circulation sheet lining made of high-density polyethylene (PE-HD) with a polypropylene fleece, PE-HD sealing sheeting and a final protective fleece made of polypropylene, polyethylene and polyamide. It is flexible, insensitive to mechanical damage, resists ageing processes and is highly resistant to acids and other chemicals [198]. The system's overall Material Cycle Status can be deduced from its individual components. EPDM roof sealing sheeting The advantages of ethylene-propylene-dienemonomer (EPDM) flat roof sealing sheeting are the high degree of its prefabrication in the factory (so fewer seams have to be made

manually, reducing the risk of leaks) and installation without an open flame (homogeneous mater­ial, heat-welded). EPDM remains durable for more than 50 years, needs very little maintenance, is resistant to roots, biocide-free and naturally UV-resistant. Unlike other plastics it does not contain plasticisers and does not compromise groundwater. It is suitable for all flat roof systems, including greened roofs (Fig. B 2.45). It can be laid loosely without adhesion, with weighting or mechanically fixed – an advantage for its subsequent recovery. The foils are homogeneous (no backing or lamination), so they can easily undergo a further utilisation process. This is the case for vulcanised EPDM waste from the ­production process as well as cleaned waste EPDM foils from renovations. Foil waste can be downcycled as granulate in fall protection mats for children’s playgrounds, for example. Since it has a high calorific fuel value, however, it is mostly further used in energy gener­ation. Recently, one manufacturer has begun recycling its own EPDM to produce new EPDM sealing, although this is done only to a very ­limited extent (around 5 %), due to a lack of returned material [199].

B 2.43 Sheep’s wool on kraft paper as windproofing B 2.44 Triple-layered cellar sealing system B 2.45 EPDM roof sealing sheeting with potential for ­further use

B 2.45

93

Biotic materials Metallic materials Fossil-based materials

Vapour diffu­ sion resistance factor [µ]

Material classification [DIN EN 13 501-1]

Lifetime

E

> 50

Material Seals, separating layers

Thickness [mm]

Separation layer / trickle ­protection (greyboard)  *)

0.34

Trickle protection (kraft paper)  *)

0.1

400 (sd value 0,04 m)

E

50

Windproofing (sheep’s wool / kraft paper)  *)

2

400 2)

E

50 2)

Roof sealing (plant-based)  *)

3

28,000 3)

E

30

Vapour-proofing (aluminium)  *)

0.05

50,000,000 infinite (sd value 2500 m)

A1

> 50

PE-HD deck underlay, housewrap and facade ­facing  *)

0.22

114 (sd value 0.025 m)

E

PE-LD vapour barrier  *) 4)

0.2

500,000 (sd value > 100 m)

E

2 – 5 1)

Material Cycle Status

Additional recycling potential

0 %   20 %   40 %   60 %   80 %   100 %

MRC MLP MEoL

MRC MLP MEoL

MRC MLP MEoL

MRC MLP MEoL

MRC MLP MEoL 30 MRC MLP MEoL 50

Bitumen sealing sheeting 5)

3 – 5

50,000

E

50

EPDM roof sealing sheeting  *)

1.3 /1.5

70,000

E

> 50

MRC MLP MEoL

MRC MLP MEoL

Wiederverwen

Wiederverwert

Weiterverwend

Weiterverwertu MRC MLP MEoL

Herstellerrück

Kompostierun

*) Data supplied by the manufacturer; they refer to select products and are not applicable to the entire product category. The published table entries are reference values that may differ significantly from those of individual cases. 1) based on fibreboard panels in general  2) based on kraft paper  3) based on a comparable product by the same manufacturer  4) MLP: Material may be partly recyclable (based Energetische V on a comparison to the manufacture of other products) in the authors’ opinion  5) MLP based on manufacturer data, all other information general B 2.46

94

The Recycling Potential of Building Materials

Openings and Glazing Units Large glazing units, windows and doors are highly optimised structural components. Estimating their recycling potential is just as complex as joining them and as wide as the range of their different product components. The general remarks below are designed to help readers assess the compatibility of openings and glazing with an urban mining approach. The first issue is that of disassembling units without destroying them in order to obtain pure materials. Structural connections

While today’s high-tech glass facade structures are preferably mechanically mounted and windproofed with clamped foil joining sheeting, usually made of ethylene-propylene-dienemonomer (EPDM), joints are unfortunately still often bonded with building foam and sealed with synthetic sealing compounds. Materials that are filled or clamped on can be used for smaller openings as an alternative to glued or foamed joints, allowing for the recovery of pure materials.

is similar to that of hemp and jute insu­lating materials (Fig. B 2.42, p. 91) [200]. Hemp sealing tape is another way of using hemp fibres to seal joints around windows and doors (caulking strip, Fig. B 2.48, p. 96). Caulking strip is made by needling and felting the fibres to make a long tape. The material is pressed into the joint void-free with a spatula, trowel or knife. Joints sealed with hemp sealing tape can easily absorb changes in their width without developing leaks, because the material is very elastic. Hemp’s positive qual­ ities here are similar to those of loose fibrous filler (see “Hemp fibre insulating panels, felt or wool”, p. 88f.) [201].

Fossil-based materials: PU and EPDM The range of applications for polyurethane (PU) sealing tape is comparable with that for the biotic joint sealing described above. This permanently elastic, pre-compressed foam sealing tape is usually made of soft, open-celled polyurethane. Impregnation ­enables the pre-compressed tape to return to its initial form after some time, protects the backing material (foam) from UV and ­ageing, and has a water-repellent and flameretardant effect. The only recyclable product of this kind has unfortunately been withdrawn from the market due to a lack of demand [202].

Biotic materials: hemp and jute To make loose fibre filler, hemp or jute fibres are impregnated with 2 – 5 % soda to protect them from fire. Both fibres are moisture-regulating, mould-resistant and easy to work with in vapour-permeable structures, so fibrous filler is used to permanently close narrower joints around windows and doors and for wall connections. Joints must, however, be protected from moisture by covering the structural elem­ ent (e.g. with strips or trims). Fibrous filler does not contain any additives, so it can be composted. Its potential for use in a materials cycle

B 2.46 Material Cycle Status: seals and separating ­layers MRC = Material Recycling Content MLP = Material Loop Potential MEoL = Material End of Life (see also sample graphic Fig. B 2.4 a, p. 64) B 2.47 No painting and repainting required: Alpine trust in wooden windows, Stiva da morts (mortuary), Vrin (CH) 2002, Gion A. Caminada

B 2.47

95

B 2.48

Ethylene-propylene-diene-monomer (EPDM) foil connecting sheets are suitable for the ­exterior sealing especially of large-format ­glazing (and for perimeter areas, see “Sealing between the frame and structure”, p. 56). The sheets are characterised by very high resistance to weathering and extreme tem­ peratures and are very elastic. EPDM can potentially be downcycled (see “EPDM roof sealing sheeting”, p. 93).

of fossil-based materials”, p. 62), so they will not be further considered here. If plastic frame windows, doors or roller shutters have to be disposed of during a building’s con­ version, dismantling or renovation, a system operating across Germany will recycle them for a fee. The material’s inferior performance means that the recovered PVC granulate is used only as a recyclate in the non-visible core of new windows and not for the surface [203].

Sealing for glazing

Biotic materials Wood used in window profiles in Germany is usually painted or varnished. Here, it may be instructive to look at Austria and Switzerland, where more credit is given to the properties of raw wood than to a coat of paint, which will only last for around eight years, anyway (Fig. B 2.47, p. 95) [204]. Even if it may be experimental because it does not conform with accepted technical standards and is not recommended by the ift Rosenheim [205], the maintenance work ­windows require can be reduced. The prospects of recycling their materials to make new, high-quality products can be increased by using wood in an appropriate durability class or thermally modified timber and providing ­sufficient structural protection for wood (with a projecting roof, etc.) (see “Thermally modified timber”, p. 73) [206].

Large post-and-beam facades are dry-glazed, which makes it easier to replace or repair a pane with EPDM sealing profiles. Many smaller windows are often wet-glazed, i.e. the panes are sealed in with a permanently elastic synthetic (e.g. silicone), which has the advantage of making small irregularities in the frame (e.g. in wood-frame windows) easier to even out. Its disadvantages are the higher cost and effort (UV light makes silicone brittle) involved in maintaining and repairing frames and the limited purity of materials for recycling due to sealants adhering to frames. Frame and profile materials

Frames and profiles are often made of wood, metallic materials or PVC. PVC plastic-frame windows are not recommended for projects taking an urban mining and pollutant-free approach to building (see “Recycling potential

Metallic materials Aluminium, painted steel, stainless steel and weathering structural steel frames are especially suitable for recycling (Fig. B 2.25, p. 78). This can, however, be complicated or may not even be worthwhile. The metal shell around foamed profiles, for example, is very thin and the frame only retains its stability due to the adhesive bond with the foam.

B 2.49

96

A product’s certification can be helpful in estimating its material recycling potential and environmental impact. The example of a Cradleto-Cradle-certified aluminium-frame window clearly shows the advantages: components made of PVC (e.g. contained in insulators) and other toxic substances are substituted for safer materials (Fig. B 2.49). The proportion

of recycled aluminium used is also stated (at least 40 % in the example of the product shown), the detachability of connections is evaluated, and individual components are ­assigned to a recycling cycle. A consortium of manufacturers, A I U I F e. V. Aluminium ­Wert­stoffkreislauf, guarantees the recycling of pure aluminium in Germany for making ­products of the same quality (see “Circularity in ­Architecture – Urban Mining Design”, p. 10ff.) [207]. Glazing and the space between the panes

Insulating glazing is a highly developed product and has for some time been made of more than just float glass. Panes are often coated to help save energy and regulate their g-value, to stop dirt from sticking to them and for easier cleaning. However, the coatings impede recycling to the same quality. New insulating float glass panes are currently made of a maximum of 30 % of recycled glass, usually pre-consumer material or reused material from the manufacturer’s own production processes [208]. A C2C-certified insulating glass is available that contains 10 % post-use recycled glass [209]. Noble or inert gasses such as argon or krypton in the space between the panes reduce the heat transition coefficient (up to 0.4 W/m2K of triple insulating glazing units) and improve their soundproofing. These costly gases are, however, lost when insulating glazing units are shredded [210]. Pane spacers are made of metal or plastic composite that manufacturers refer to as a “warm edge”. Butyl, polyurethane or polysulfide are used as sealing [211]. The recycling of these materials is not yet relevant, because of the very small quantities involved. Additional materials are sometimes installed in the space between the panes to protect ­interiors from solar radiation, deflect or diffuse daylight, or to improve thermal insulation. These materials which, based on ­current knowledge, pose no risk to health, range from easily recyclable timber or aluminium slats to polymethyl methacrylate plastic tubes (PMMA, also called acrylic glass; see also

The Recycling Potential of Building Materials

B 2.50 Material Glazing

    Material Cycle Status

Additional recycling potential

Float glass for insulation glazing  *) Mineral material

0 %   20 %    40 %    60 %   80 %   100 %

MRC MLP MEoL

*)  Data supplied by the manufacturer; they refer to select products and are not applicable to the entire p ­ roduct ­category.

B 2.51

Cascade utilisation of glass (with quality and processing requirements and usage ranking both decreasing from top to bottom) Quality and processing requirements

the example of the “Recyclable Channel Glass Facade”, p. 187). Polyvinyl butyral foils (PVB foils) help to secure features such as break-in protection, resistance to blasts and impacts, high levels of ­load-bearing capacity and soundproofing in laminated safety glass units. Some units have special inlays that create the bond between the panes. Despite the large quantities of polyvinyl butyral foils that industry (including the car industry) generates, efforts to strictly separate and recover high-quality PVB have succeeded only recently, although the process for doing this is not yet standard [212]. An intumescent intermediate layer is installed in some fire-resistant glazing units that reacts to fire by foaming up [213]. Its combination of silicate solution and polyglycol contains bonded water that evaporates when it heats up and contributes to the formation of a binding glass foam that enables the pane to resist fire [214]. All these components are the outcomes of highly technical research and provide highquality glazing without, however, developing the product design and its component parts under the aspect of recycling or thinking about the end of its life, which locks the insulating glazing unit, a high-quality product, into a downcycling process (Fig. B 2.52).

Float glass consisting of approx. 10 % post-consumer float glass and ≤ 30 % recycling material from its own production (pre-consumer component) Textile glass fibre

White / brown container glass + cast glass consists of approx. 60 % waste glass 1) Green container glass consists of approx. 90 % waste glass 1) Insulating fibreglass

Foam glass consists of approx. ≤ 70 % waste glass 2)

B 2.48 Hemp oakum in use: sealing windows by ­packing B 2.49 C2C-certified window system: designed for ease of recycling with no harmful substances B 2.50 High-value recycling of aluminium frame profiles in an aluminium recycling facility B 2.51 Material Cycle Status: glazing MRC = Material Recycling Content MLP = Material Loop Potential MEoL = Material End of Life (see also sample graphic Fig. B 2.4 a, p. 64) B 2.52 Utilisation cascade of float glass

Foam glass gravel consists of 100 % waste glasss 3)

Brick

Usage ranking https://www.agr.at/glasrecycling, retrieved on 30.05.2019 https://www.wecobis.de/bauproduktgruppen/daemmstoffe/aus-mineralischen-rohstoffen/schaumglas.html, retrieved on 04.08.2017 3)  https://www.wecobis.de/bauproduktgruppen/grundstoffe-gs/gesteinskoernung-gs/ industriell-hergestellte-gesteinskoernungen/blaehglas-gs.html, retrieved on 04.08.2017 B 2.52 1) 

2) 

97

Notes:   [1] Waste hierarchy in accordance with the Waste Framework Directive, Chpt. 1, Art. 4 and the Waste Management Act § 6   [2] http://www.bauteilboerse-bremen.de. Retrieved on 18.07.2018 https://restado.de/bauteilboerse/. Retrieved on 14.06.2018 https://www.salza.ch/de. Retrieved on 18.07.2018 http://materialnomaden.at/harvestmap. Retrieved on 18.07.2018   [3] German Federal Environmental Agency), Bio Wastes, retrieved on 25.01.2017   [4] Ordinance on the Recovery of Bio-Waste on Land used for Agricultural, Silvicultural and Horticultural Purposes (Bio-Waste Ordinance – BioAbfV) Publication date: 21.09.1998 To date: reformulated in publication dated 4.04.2013 I 658; most recent change Art. 5 V on 5.12.2013 I 4043   [5] Helmus, Manfred; Randel, Anne by order of the ­Bundesministerium für Verkehr, Bau und Stadtentwicklung – BMVBS: “Strategien für einen optimalen Stoffkreislauf”. Final report. Research programme Zukunft. Ref. no.: 10.08.17.7-11.39. Berlin 2013, p. 66 and 71   [6] German Federal Environmental Agency, Non-iron Metals Industry, retrieved on 25.01.2017; KME ­Germany GmbH & Co. KG, Osnabrück   [7] German Federal Environmental Agency, Non-iron Metals Industry, retrieved on 25.01.2017   [8] WECOBIS – Ökologisches Baustoffinformations­ system, Metals, retrieved on 29.12.2016   [9] Recycling magazin, “Legierungen bei Metallschrott erkennen”, 09.06.2016. https://www.recycling­ magazin.de/2016/06/09/legierungen-bei-metall­ schrott-erkennen/. Retrieved on 15.10.2017 [10]  see note 7 [11] German Federal Environmental Agency: “Verrottet Plastik gar nicht oder nur sehr langsam?”, 08.09.2017, https://www.umweltbundesamt.de/­ service/uba-fragen/verrottet-plastik-gar-nicht-nursehr-langsam. Retrieved on 11.11.2016 [12] Table BBSR: Nutzungsdauern von Bauteilen für ­Lebenszyklusanalysen nach Bewertungssystem Nachhaltiges Bauen (BNB) http://www.nachhaltigesbauen.de/fileadmin/pdf/ baustoff_gebauededaten/BNB_Nutzungsdauern_ von_Bauteilen_2017-02-24.pdf. Retrieved on 30.12.2016 [13] Consultic Marketing & Industrieberatung GmbH: Produktion, Verarbeitung and Verwertung von ­Kunststoffen in Deutschland 2015, summary. Alzenau 2016 [14] Hegger, Manfred et al: Baustoff Atlas. Munich 2005, p. 91ff. [15]  see note 13 [16]  see note 13 [17] Kalberlah, Fritz; Schwarz, Markus, by order of the German Federal Environmental Agency: “Karzinogene, mutagene, reproduktionstoxische (CMR) und andere problematische Stoffe in Produkten”, summary, 08/2011, https://www.umweltbundesamt.de/sites/default/ files/medien/461/publikationen/k4092.pdf. ­Retrieved on 30.12.2016 [18] WECOBIS – Ökologisches Baustoffinformations­ system, Bitumen, retrieved on 05.11.2017 [19] WECOBIS – Ökologisches Baustoffinformations­ system, Natural stone floor coverings, retrieved on 22.06.2017 [20] Forum Nachhaltiges Bauen, Zement Ökobilanz, ­retrieved on 05.11.2017 [21] Hebel, Dirk: Sand (part 1): “eine endliche Ressource”. ETH Zurich Zukunftsblog, Zukunftsstädte, 14.10.2014 https://www.ethz.ch/de/news-und-veranstaltungen/ eth-news/news/2014/10/sand-teil-1-eine-endlicheressource.html. Retrieved on 21.06.2017 [22] Peduzzi, Pascal: “Sand, rarer than one thinks.” United Nations Environment Program, 03/2014 https://na.unep.net/geas/archive/pdfs/GEAS_

98

Mar2014_Sand_Mining.pdf. Retrieved on 22.06.2017 [23] Ertinger, Sebastian: “Sand wird zur Schmuggelware”. In: Handelsblatt, 13.06.2013 [24] Mineralische Bauabfälle Monitoring 2014 – Bericht zum Aufkommen und zum Verbleib mineralischer Bauabfälle im Jahr 2014, Kreislaufwirtschaft Bau, published by Bundesverband Baustoffe – Steine und Erden e. V.. Berlin 2017 [25] ibid. [26] Rüter, Sebastian: “Welchen Beitrag leisten Holzprodukte zur CO2-Bilanz?” In: AFZ, der Wald 15/2011, p. 15 [27] Deilmann, Clemens et al., by order of the Bundes­ institut für Bau-, Stadt- und Raumforschung – BBSR: “Materialströme im Hochbau. Potenziale für eine Kreislaufwirtschaft”. Zukunft Bauen, Forschung für die Praxis. Vol. 06. Ref. no: SWD 10.08.17.7-12.29. Bonn 2017, p. 22 [28]  ibid., p. 50 [29] see note 12 and Nutzungsdauerkatalog der BauEPD GmbH about the preparation of EPDs. Published by Bau EPD GmbH http://www.bau-epd.at/ wp-content/uploads/2015/08/EPD-AT_Referenz­ nutzungsdauern-20150810.pdf [30] DIN EN 1990:2010-12, Eurocode: Basis of Structural Design; German version EN 1990:2002 + A1:2005 + A1:2005/AC:2010, table 2.3 planned usage lifetime [31] Schutzgemeinschaft Deutscher Wald Landesverband NRW e. V. (SDW/NRW), “Alter der Bäume”. http://www.sdw-nrw.de/waldwissen/oekosystemwald/alter-der-baeume/. Retrieved on 14.12.2016 [32] https://deutschezertifizierungsberatung.de/fscpefc/. Retrieved on 30.05.2019 [33] Ordinance Of Requirements For The Recovery And Disposal Of Waste Wood (Waste Wood Ordinance – AltholzV), to date: most recent change Art. 96 V on 31.08.2015 I 1474 [34] Gärtner, Sven et al., by order of the ifeu–Institut für Energie- und Umweltforschung Heidelberg gmbH: Ökobilanz der kaskadierten Nutzung nachwachsender Rohstoffe am Beispiel Holz – eine Einordnung. Heidelberg [35]  see note 33 [36] Mantau, Udo: “Holzrohstoffbilanz Deutschland. ­Entwicklungen und Szenarien des Holzaufkommens und der Holzverwendung von 1987 bis 2015”. Hamburg 2012 and http://www.epub.sub.uni-hamburg.de/epub/volltexte/2013/23574/pdf/dn051281.pdf. Retrieved on 30.05.2019 [37]  see note 27, p. 37 [38] Forum Nachhaltiges Bauen, Brettschichtholz Öko­ bilanz, retrieved on 01.05.2017 [39]  DIN 68 800-1:2011-10, 7.1.1 and 7.1.2 [40] based on DIN 68 800-1:2011-10, Wood protection – Part 1: General information, 8.1.3 [41] DIN EN 350:2016-12, Durability of wood and wood products – testing and classification of the durability of biological agents of wood and wood-based ma­ terials; German version EN 350:2016, 5.2 table 1 – durability classes of wood-based materials to attack by decay fungi [42] EN 13 986:2015-06, Wood products for use in construction – properties, conformity assessments and labelling: German version EN 13 986:2004+A1:2015 [43] DIN EN 13 501-1:2010-1 Fire classification of construction products and building elements – part 1: Classification using data from reaction to fire tests; German version EN 13501-1:2007+A1:2009, A.4 ­Relationship between classes and reference fire scenarios. A.4.2 For all building products except floor coverings [44] DIN EN 1995-1-2:2010-12, German version EN 1995-1-2:2004 + AC:2009, table 3.13.1 – measurements of burn rates […] for structural timber, lamin­ ated veneer lumber, timber claddings and timber products [45] Helmus, Manfred; Randel, Anne (Bergische Uni­ versität Wuppertal), by order of bauforumstahl: Sachstandsbericht zum Stahlrecycling im Bauwesen. p. 4 and

https://bauforumstahl.de/upload/documents/­ nachhaltigkeit/Sachstandsbericht.pdf. Retrieved on 02.01.2017 [46] WECOBIS – Ökologisches Baustoffinformations­ system, Steel. Retrieved on 25.01.2017 [47] http://www.stahl-online.de/index.php/themen/energie-und-umwelt/recycling/. Retrieved on 10.02.2017 [48]  see note 45 [49] Project proposal 12.04.2016, entitled: “Entwicklung und Validierung einer Methode zur Erfassung der Sammelraten von Bauprodukten aus Metall”, DBU ref. no: 32396/01-23. Proposed by: Bergische ­Universität Wuppertal, Interdisziplinäres Zentrum III, Management technischer Prozesse, Helmus, Manfred; Randel, Anne; collaborators: bauforumstahl e. V., Hauke, Bernhard; Siebers, Raban [50] Stahl-Zentrum (eds.): “Themenpapier RecyclingWeltmeister Stahl”. Düsseldorf [51]  ibid and see note 45 [52] https://bauforumstahl.de/architektur-korrosions­ schutz. Retrieved on 10.02.2017 [53] http://www.feuerverzinken.com/fileadmin/Uploads_ Glinde/Broschueren/Korrosionsschutz_durch_­ Feuerverzinken.pdf, p.6. Retrieved on 12.02.2017 [54] DIN EN ISO 14 713-1:2010-5 Zinc coatings – ­guidelines and recommendations for the protection against corrosion of iron and steel in structures – part 1: General principles of design and corrosion resistance (ISO 14713-1:2009); German version EN ISO 14 713-1:2009 [55] http://www.feuerverzinken.com/nachhaltigkeit/­ nachhaltigkeit/. Retrieved on 10.02.2017 [56] http://www.feuerverzinken.com/fileadmin/user_­ upload/pdf/Leitfaden_Feuerverzinken_-_Nach­ haltiges_Bauen_-_Online.pdf, p. 18. Retrieved on 11.02.2017; and see note 46 [57] German Federal Environmental Agency, Volatile ­Organic Compounds. https://www.umweltbundes­ amt.de/themen/gesundheit/umwelteinfluesse-aufden-menschen/chemische-stoffe/fluechtige-orga­ nische-verbindungen#textpart-1. Retrieved on 23.11.2017 [58] https://www.bauforumstahl.de/upload/documents/ brandschutz/Broschure.pdf. Retrieved on 28.04.2017 [59] http://www.chemie.de/lexikon/Vinylacetat.html. ­Retrieved on 05.11.2017 [60] Eurocode 3: Design of steel structures – part 1-2: General rules – structural fire design; German ­version EN 1993-1-2:2005 + AC:2009 [61]  see note 27, p. 21, 28 –31 [62] Müller, Anette, by order of the Bundesinstitut für Bau-, Stadt- und Raumforschung (BBSR): “Erschlie­ ßung der Ressourceneffizienzpotenziale im Bereich der Kreislaufwirtschaft Bau”. Final report. As of 12.02.2016. BBR Ref. no.: 10.08.17.7-14.27. Research programme Zukunft Bau. Weimar 2016, p. 64 – 72 [63]  see note 27, p. 21, 28 – 31 [64]  see note 62 [65] Bundesministerium für Verkehr, Bau und Stadtentwicklung – BMVBS (eds.); Helmus, Manfred, Randel, Anne: “Strategien für einen optimalen Stoffkreislauf”. Final report. Research programme Zukunft. Ref. no.: 10.08.17.7-11.39. Berlin 2013, p. 54 [66] https://www.ecodesign-beispiele.at/w010-ziegelaus-recycling.html. Retrieved on 22.04.2017 [67]  see note 27, p. 21, 28 –32 [68]  see note 27, p. 21, 28 –32 [69]  see note 62 [70] Xella Deutschland GmbH, Duisburg, product: Ytong Porenbeton and Silka Kalksandstein [71]  see note 27, p. 21, 28 – 31 [72] Ministerium für Umwelt, Naturschutz und Verkehr Baden-Württemberg (eds.): “RC-Beton im Bau­ bereich. Informationen für Bauherren, Planer und Unternehmen”. Stuttgart 2011, p. 13f., 22 [73] www.builtby.tv/UBA-ZIEL-2019-Presse. aspx?id=6e777b47-8895-4e3a-a7b83c957d973c95, retrieved on 20.05.2017 [74] WECOBIS – Ökologisches Baustoffinformations­ system, Aggregates, retrieved on 24.04.2017

The Recycling Potential of Building Materials

[75] see note 72; WECOBIS – Ökologisches Baustoffinformations­ system, Concrete, retrieved on 26.11.2017 [76]  see note 27, p. 21, 28 – 31 [77] Hoffmann, Cathleen; Huth, Olaf, by order of EMPA: “Konstruktionsbeton aus recyclierter Gesteins­ körnung (Beton- und Mischabbruchgranulat). ­Abschlussbericht zu den Untersuchungsschwerpunkten”. Dübendorf 2006, https://www.empa.ch/ documents/55996/231454/Konstruktionsbeton%2Ba us%2Brecyclierter%2BGesteinsk%25F6rnung.pdf/ d82100cc-d145-4b75-934b6676a910b591?version=1.0, retrieved on 24.11.2017 [78]  see note 62 [79]  see note 12 [80] Act on Managing Water Resources (Federal Water Act) WHG enacted: 31.07.2009, full quote: “Wasserhaushaltsgesetz vom 31. Juli 2009 (BGBl. I p. 2585), das zuletzt durch Artikel 122 des Gesetzes vom 29. März 2017 (BGBl. I p. 626) geändert worden ist”, status: most recent changes to Art. 122 G on 29.3.2017 I 626, §55(2) and Initiative pro Metalldach in collaboration with the state of Baden-Württemberg, Ministerium für Umwelt, Naturschutz und Verkehr (eds.): “Umweltgerechte Regenwasserversickerung von kupfer- und zink­ gedeckten Dachflächen”. Brochure. 2010. http:// www.umweltforum-kupfer-zink.de. Downloaded 17.05.2017 [81]  see note 12 [82] Bad Essener Sägewerk GmbH & Co. KG, Bad Essen-­Wehrendorf, Produkt: Thermoholz; Scheiding, Wolfram; Plaschkies, Katharina; Weiß, Björn, by order of the Institut für Holztechnologie Dresden IHD: ­Bulletin TMT.02 Dauerhaftigkeit von TMT ­(Thermoholz) 07/15-M TMT02. Dresden 07/2015 [83] DIN 68 800-1:2011-10, Wood protection – part 1 DIN 68 800-1:2011-10, Appendix A [84] DIN 68 800-1:2011-10, Wood protection – part 1 DIN 68 800-1:2011-10, 8.1.5 and 8.1.6; DIN CEN/TS 15 679:2008-03, Thermally Modified Timber – definitions and characteristics; German version CEN/TS 15 679:2007 [85] Informationsdienst Holz Außenbekleidungen mit ­Holzwerkstoffplatten, R01_T10_F04_Aussenbekl_ Holzwerkstoffplatten_2001.pdf, retrieved on 16.06.2017 [86] WECOBIS – Ökologisches Baustoffinformations­ system, Plywood and laminated veneer lumber. ­Retrieved on 10.06.2017 [87] WECOBIS – Ökologisches Baustoffinformations­ system, Timber building products. Retrieved on 10.06.2017 [88] Meteon Fire Retardant EPD-TRE-2012111-D, DEDeutschland_EPD Trespa Meteon FR_(EPD-TRE2012111-D)_28-06-2012_tcm37-46743 [89]  see note 12 [90] HISS REET Schilfrohrhandel GmbH, Bad Oldesloe, thatched roof [91] WECOBIS – Ökologisches Baustoffinformations­ system, Non-rusting steel. Retrieved on 11.02.2017 [92] ibid. [93] https://www.stahl-online.de/wp-content/uploads/ 2017/10/MB434_2017_ns.pdf. Retrieved on 30.05.2019 Table 2: Rust allowances based on table 2 of [4] for three corrosion loads: heavy, moderate, light; Fig. 8: Rust curves for carbon steel and weathering steel in accordance with ISO 9224 for corrosion ­category C4 (upper limit) [94] WECOBIS – Ökologisches Baustoffinformations­ system, Aluminium. Retrieved on 16.07.2017; Urban Mining – Ressourcenschonung im Anthropozän. Published by the German Federal Environmental Agency. Dessau-Roßlau 07/2017, p. 59 http://www.umweltbundesamt.de/publikationen/­ urban-mining-ressourcenschonung-im-anthropozaen, retrieved on 24.09.2017 [95] Aluminium profile panels for roof, wall and floor ­constructions IFBS, EPD-IFBS-2013111-D, 2013, 131125_EPD-IFBS-

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J. B. Kaufmann GmbH, Nenndorf-Westerholt; Hagemeister GmbH & Co. KG, Nottuln [113]  see note 62 [114] Bauglasindustrie GmbH, Schmelz (NSG Group), product: Pilkington Profilit [115] MAGNA Naturstein GmbH Abt. Glaskeramik, Teutschenthal, Product: Structuran-Glaskeramik; Wuppertal Institut für Klima, Umwelt, Energie gGmbH, Wuppertal [116] http://www.dachbegruenung-ratgeber.de/dach­ begruenung. Retrieved on 17.03.2018 [117] http://decostones.de/glaskies/glassplitt.htm. ­Retrieved on 01.08.2017 [118] PV Market Alliance (PVMA): PV Market Alliance ­announces the 2016 PV market at 75 GW and a stable market in 2017. Press release http://www.pvmarketalliance.com/pv-market-­ alliance-announces-the-2016-pv-installations-at75-gw-and-a-stable-market-in-2017/. Retrieved on 24.05.2017 [119]  see note 5, p. 78 [120] http://www.photovoltaik.org/photovoltaikanlagen/ solarmodule/degradation-von-solarmodulen. ­Retrieved on 07.03.2018 [121] http://www.pvcycle.de/press/breakthrough-in-pvmodule-recycling-2/. Retrieved on 26.06.2017 [122] German Federal Environmental Agency, POPand PCB-containing wastes, 31.08.2017. https:// www.umweltbundesamt.de/themen/abfall-ressourcen/abfallwirtschaft/abfallarten/gefaehrliche-­ abfaelle/pop-pcb-haltige-abfaelle. Retrieved on 15.03.2018

[123] http://bonsum.at/magazin/biokunststoffe-eine-­ oekologische-alternative. Retrieved on 30.05.2019 [124] https://fnr.de/fileadmin/allgemein/pdf/broschueren/WEB_Biokunststoffe_2018.pdf. Retrieved on 30.05.2019; ZinCo GmbH, Nürtingen, product: ZinCo System­ aufbau natureline [125] Massivholz Junker GmbH, Nordrach, product: GMF-Diagonalplatte [126] EGGER Holzwerkstoffe Wismar GmbH & Co. KG, Wismar, product: EUROSPAN Rohspanplatten; http://www.baubiologie.net/fileadmin/_migrated/ content_uploads/Ver_Wohngifte_Formaldehyd_im_ Holz.pdf. Retrieved on 01.05.2017 Forum Nachhaltiges Bauen, OSB-Platten und Spanplatten Ökobilanz. Retrieved on 01.05.2017 [127] http://www.schadstoffberatung.de/holz.htm. Retrieved on 08.07.2017 [128] SWISS KRONO GmbH, Heiligengrabe, product: Kronoply OSB [129] Forum Nachhaltiges Bauen, OSB-Platten und Spanplatten Ökobilanz, retrieved on 01.05.2017 [130] European Panel Federation, Annual Report 20162017. Cited in: Recycling Magazin. Issue 14/2017, 26.07.2017, p. 27 [131] PD Spanplatte roh, EPD-VHI-20130001-IBG1-DE, EPD Spanplatte, roh IM0005534.pdf [132] Pfleiderer Deutschland GmbH, Neumarkt, product: LivingBoard P4 P5 P7 [133]  see note 129 [134] Kronospan Schweiz AG, Menznau, product: KRONOTEC MDF dampfdiffusionsoffen [135] Fundermax Swiss AG, Kleindöttingen, product: FunderPlan Biofaser [136] Istraw – straw-based building materials, Kirch­ anschöring, product: Stohbauplatte [137] Röhlen, Ulrich; Ziegert, Christof: Lehmbau-Praxis. Planung und Ausführung. Berlin 2014, p. 113 [138]  ibid., p. 44 [139] Rat für Nachhaltige Entwicklung (eds.) “2017 Zu­ kunft Kreislaufwirtschaft: Erarbeitung einer Poten­ zialabschätzung von innovativen Geschäftsmodellen”, a study by Philipp Buddemeier (accenture AG) and Knut Sander (Ökopol Institut für Ökologie und ­Politik GmbH) by order of the Nachhaltigkeits­ rat, Berlin [140] Buchert, Matthias et al., by order of the German Federal Environmental Agency: “Ökobilanzielle Betrachtung des Recyclings von Gipskartonplatten”. Final report. Texts 33/2017. Umweltforschungsplan des Bundesministeriums für Umwelt, Naturschutz, Bau- und Reaktorsicherheit. Dessau-Roßlau 2017, p. 42 – 44, 51, 58, 67, 89 http://www.umweltbundesamt.de/publikationen/ oekobilanzielle-betrachtung-des-recyclings-von. Retrieved on 05.06.2017 [141]  see note 24 [142]  see note 140 [143] http://gypsumrecycling.biz/15841-1_Thesystem. Retrieved on 05.06.2017 [144]  see note 27, p. 34 [145]  see note 140 [146] Kreidezeit Naturfarben GmbH, Lamspringe, ­product: Tadelakt-weiß [147] Gussasphalt 47 technische Informationen: “Guss­ asphalt von A– Z. Bauweisen”. Published by bga Beratungsstelle für Gussasphaltanwendung e. V. Bonn 01/2014; Asphaltverband (eds.): Bautechnik – Hinweise zur Asphaltbauweise, 6. Baustoffe und Baugemische, p. 22ff., https://www.asphalt.de/fileadmin/user_­ upload/technik/baustoffe_und_baustoffgemische. pdf. Retrieved on 09.11.2017; Asphaltverband (eds.): Bautechnik – Hinweise zur Asphaltbauweise, 11. Gestaltungsaspekte, p. 47, https://www.asphalt.de/fileadmin/user_upload/ technik/gestaltungsaspekte.pdf. Retrieved on 09.11.2017 [148]  CREATON AG, Wertingen, product: Estrichziegel [149]  DGNB-System Version 2017 [150] Forbo Flooring GmbH, Paderborn, product: ­Marmoleum 2.0 and 2.5 mm

99

[151] https://www.oekologisch-bauen.info/baustoffe/ bodenbelaege/linoleum.html. Retrieved on 12.03.2018 [152] Desso Holding BV, A Tarkett Company, Waalwijk, product: Desso Teppichboden-Fliese Fields Gold [153] https://www.bmub.bund.de/pressemitteilung/langfristige-regeln-fuer-die-entsorgung-hbcd-haltigerabfaelle/. Retrieved on 10.11.2017 [154] Hahn, Bettina: “Entsorgung und Recycling von EPS- und XPS-Dämmstoffen”. In: Energieeffizienz in Gebäuden. Yearbook 2017. Published by Pöschk, Jürgen. Berlin 2017, p. 139 –144 [155] Fachagentur Nachwachsende Rohstoffe e. V. – FNR (eds.): “Baustoffe aus nachwachsenden Rohstoffen”. Brochure. Gülzow-Prüzen 2015, p. 19 https://mediathek.fnr.de/media/downloadable/ files/samples/b/r/brosch_baustoffe_web.pdf. ­Retrieved on 24.06.2016 [156] Zeitbild Fachmodul Dämmung 4 http://www.zeitbild.de/wp-content/uploads/2017/02/Zeitbild-Fachmodul-Daemmung-4. pdf, retrieved on 10.03.2017 [157] WECOBIS – Ökologisches Baustoffinformations­ system, Fibreboard insulation, retrieved on 06.01.2017 [158] Bundesinstitut für Bau-, Stadt- und Raumforschung (BBSR) Zukunft Bauen (eds.): “Ökologische Bau­ stoffwahl – Aspekte zur komplexen Planungsaufgabe Schadstoffarmes Bauen”. Forschung für die Praxis, Vol. 4. Bonn 2016 [159]  see note 157 [160] UdiDämmsysteme GmbH, Chemnitz, Product: Uditherm Sk [161] Bau-Fritz GmbH & Co. KG, Erkheim, Product: Hoiz – Hobelspandämmung [162] WECOBIS – Ökologisches Baustoffinformations­ system, Cork insulation, retrieved on 10.01.2017 [163] ZIRO – Lothar Zipse e.Kfm., Kenzingen, product: Corktherm 040 [164] King Kork BÜS – Bürgerservice gemeinnützige ­Gesellschaft zur Integration Arbeitsloser mbH, Trier, product: King Kork [165] WECOBIS – Ökologisches Baustoffinformations­ system, Cellulose fibre insulation, retrieved on 06.01.2017 [166] WECOBIS – Ökologisches Baustoffinformations­ system, Borates, retrieved on 09.11.2017 [167] https://de.wikipedia.org/wiki/SVHC. Retrieved on 09.11.2017 [168] Peter Seppele Gesellschaft m.b.H., Feistritz, ­product: Thermofloc [169] WECOBIS – Ökologisches Baustoffinformations­ system, Flax and hemp insulating panels, retrieved on 16.02.2017 [170] Thermo Natur GmbH & Co. KG, Nördlingen, ­product: Thermo Hanf Premium Plus [171] http://www.yaacool-bio.de/index. php?article=1769. Retrieved on 23.11.2017 [172] Thermo Natur GmbH & Co. KG, Nördlingen, ­product: Thermo Jute 100 Plus [173] https://www.oekologisch-bauen.info/baustoffe/ naturdaemmstoffe/kokosfaser.html. Retrieved on 20.01.2017 [174] Amtmann, Maria et al. (die umweltberatung); ­Banner, Doris et al. (Österreichische Energie­ agentur): Dämmstoffe richtig eingesetzt. Eignung, ­Anwendung und Umweltverträglichkeit von Dämmstoffen. Vienna 11/2014, p. 42f. [175] NeptuTherm e.K., Karlsruhe, product: NeptuTherm [176] Fachagentur Nachwachsende Rohstoffe e. V. – FNR (eds.): Marktübersicht. Dämmstoffe aus nachwachsenden Rohstoffen. Gülzow-Prüzen 2017, p. 50; Isolena Naturfaservliese GmbH, ­Waizenkirchen, product: Isolena Optimal [177] see note 174, p. 52ff. [178] Bundesinstitut für Bau-, Stadt und Raumforschung im Bundesamt für Bauwesen und Raumordnung: Künstliche Mineralfaserdämmstoffe. BBSR-Berichte KOMPAKT. Bonn 2011. http://www.bbsr.bund.de/ BBSR/DE/Veroeffentlichungen/BerichteKompakt/ 2011/DL_1_2011.pdf?__blob=publicationFile&v=2. Retrieved on 10.11.2017

100

[179] WECOBIS – Ökologisches Baustoffinformations­ system, Mineral wool insulation. Retrieved on 10.11.2017 [180] Knauf Insulation GmbH, Simbach am Inn, product: Knauf Insulation Holzrahmenbau-Dämmrolle ­Naturoll 035 [181] see note 178 [182]  see note 27, p. 43 [183]  see note 178 [184] WECOBIS – Ökologisches Baustoffinformations­ system, Foam glass. Retrieved on 30.05.2019 [185]  see note 174, p. 64 [186]  see note 184 [187] Misapor Management AG, Zizers, product: Misapor 10/50 [188] WIKA Isolier- und Dämmtechnik GmbH, Ingolstadt, product: Graupappe 250 [189] https://de.wikipedia.org/wiki/Kraftpapier, retrieved on 23.11.2017 [190] Ampack AG Bautechnik, Rorschach, product: ­Sisalex 30 [191] Villgrater Natur Produkte KG, Innervillgraten, ­product: Trittschalldämmung / Winddichtung [192] Derbigum Deutschland GmbH, Föhren, product: Derbipure [193] Korff AG, Oberbipp, Product: Aluminium Grob­ korndampfsperre [194] DuPont de Nemours s.à.r.l., Contern, product: ­DuPont Tyvek Monolayer 80 [195] ISOCELL GmbH, Neumarkt am Wallersee, product: Airstop VAP Dampfbremse [196] DERBIGUM Imperbel NV/SA, Beersel, product: DERBICOAT NT [197] WECOBIS – ökologisches Baustoffinformations­ system, Bitumen roof sheeting. Retrieved on 10.09.2017 [198] ABG Abdichtungen Boden- und Gewässerschutz GmbH, DE-Hamburg, Product: ABG-KellerdichtSystem [199] CARLISLE Construction Materials GmbH, ­Hamburg, Product: Hertalan Easy Cover [200] Thermo Natur GmbH & Co. KG, Nördlingen, ­product: Thermo Stopfwolle Hanf; product: Thermo Stopfwolle Jute [201] Hanffaser Uckermann eG, Prenzlau, product: ­Hanf-Kalfaterband H-KB 30 [202] Experten-Ratgeber: Kompriband-Typen, Ver­ arbeitung und Preise im Überblick, 14.10.2016, http://www.energie-experten.org/bauen-und-­ sanieren/fenster/einbauen/kompriband.html. ­Retrieved on 08.08.2017 [203] http://www.rewindo.de/rewindo-recycling-service/ index.html. Retrieved on 02.08.2017 Information: Recycklatkern;Biotrans GmbH, Schwerte [204]  see note 12 [205] based on information from ift Rosenheim GmbH, 11.06.2018 [206] Institut für Holztechnologie gemeinnützige GmbH (eds.): Merkblattsammlung. Merkblatt TMT.10, 07/15-M TMT.10, probably July 2015 https://www.ihd-dresden.de/fileadmin/user_­ upload/pdf/IHD/wissensportal/Merkblaetter/TMT/ Merkblattsammlung.pdf. Retrieved on 10.06.2018 [207] Schüco International KG, Bielefeld, product: AWS 75.SI +, FW 50 +.SI [208] St. Gobain Glass (eds.): “DGNB und St. Gobain Glass. Für nachhaltige Lebensräume”. Brochure. Aachen 10/2012 [209] AGC Glass UK Ltd., Rugby, product: Float Glass http://www.c2c-centre.com/product/building-­ supply-materials/float-glass-and-magnetron-coatedglass. Retrieved on 02.08.2017 [210]  Bundesverband Flachglas e. V., Troisdorf [211] EPD SGG CLIMAPLUS PROTECT SGG CLIMAPLUS SILENCE AFNOR Registration No. 08261:2012, EPD_SGG_CLIMAPLUS_PROTECT_ V2.1_short version.pdf [212] http://eu-recycling.com/Archive/5772. Retrieved on 02.08.2017 [213]  see note 208 [214] http://www.vanbaerle.com/silikate/produkte-nachleistungsmerkmalen/herstellung-von-brandschutz­ glas.html. Retrieved on 02.08.2917

Fig. B 2.14 – Material Cycle Status: foundation and structure Product-specific information: Structural steel: ArcelorMittal Europe, product: Structural steel sections in HISTAR grades Sand-lime bricks: Xella Deutschland GmbH, Duisburg Aerated concrete blocks for exterior walls with no add­ itional thermal insulation: Xella Deutschland GmbH, Duisburg, product: Ytong Planblock PP2-0,35 Aerated concrete blocks for exterior walls with additional thermal insulation: Xella Deutschland GmbH, Duisburg, product: Ytong Planblock PP4-0,50 Aerated concrete blocks for non-load-bearing interior walls: Xella Deutschland GmbH, Duisburg, product: Ytong Planbauplatte PPpl-0,50 Product-neutral information: Mantau, Udo: Holzrohstoffbilanz Deutschland, Entwicklungen und Szenarien des Holzaufkommens und der Holzverwendung 1987 bis 2015. Hamburg 2012 Deilmann, Clemens et al., commissioned by the Bundes­ institut für Bau-, Stadt- und Raumforschung – BBSR: Materialströme im Hochbau. Potenziale für eine Kreislaufwirtschaft. Zukunft Bauen, Forschung für die Praxis. Vol. 06. Ref. No: SWD 10.08.17.7-12.29. Bonn 2017 Müller, Anette, commissioned by the Bundesinstitut für Bau-, Stadt- und Raumforschung – BBSR: Erschließung der Ressourceneffizienzpotenziale im Bereich der ­Kreislaufwirtschaft Bau. Final report as of 12.02.2016. Research programme Zukunft Bau. Weimar 2016 Bundesverband Baustoffe – Steine und Erden e. V. (eds.): Mineralische Bauabfälle. Monitoring 2014. Bericht zum Aufkommen und zum Verbleib mineralischer Bauabfälle im Jahr 2014. Berlin 2017 WECOBIS – ökologisches Baustoffinformationssystem, Fresh concrete. Retrieved on 26.11.2017 Fig. B 2.25 – Material Cycle Status: exterior wall, pitched roof: outside surfaces Product-specific information: Thermally modified wood: SWERO GmbH & CO. KG, Wangen im Allgäu, product: Thermory Thatch (reed): HISS REET Schilfrohrhandel GmbH, Bad Oldesloe, thatched roof Stainless steel/weathering steel: ArcwelorMittal Europe, product: Structural steel sections in HISTAR grades Copper sheet: KME Germany GmbH & Co. KG, ­Osnabrück Recycled copper sheet: KME Germany GmbH & Co. KG, Osnabrück TECU Kupferlegierungen Tafeln und Bänder, KME ­Germany GmbH & Co. KG, 2012 TECU-Eco Kupfertafeln und Bänder, KME Germany GmbH & Co. KG, 2012 Polycarbonate wall sheeting: Rodeca GmbH, Mülheim an der Ruhr, product: PC 16-7 Facing wall clinker: Hagemeister GmbH & Co. KG, ­Nottuln und Torfbrand-Klinkerwerk, Nenndorf-­ Westerholt Channel glass: Bauglasindustrie GmbH, Schmelz (NSG Group), product: Pilkington Profilit Glass ceramics: MAGNA Naturstein GmbH Abt. Glas­ keramik, Teutschenthal, product: Structuran-Glas­ keramik Product-neutral information: Mantau, Udo: Holzrohstoffbilanz Deutschland, Entwicklungen und Szenarien des Holzaufkommens und der Holzverwendung 1987 bis 2015. Hamburg 2012 ökobaudat Informationsportal Nachhaltiges Bauen, www.oekobaudat.de. Retrieved on various dates in 2017 www.alu-info.de, retrieved on 07.06.2017 Woolley, Tom, commissioned by the Institut Feuerverzinken, Düsseldorf: Feuerverzinken und Nachhaltiges Bauen. Ein Leitfaden, p. 26, Düsseldorf 03/2008 Helmus, Manfred; Randel, Anne, commissioned by the Bundesministerium für Verkehr, Bau und Stadtentwicklung – BMVBS: Strategien für einen optimalen Stoff­ kreislauf. Final report. Research programme Zukunft. Ref. No: 10.08.17.7-11.39. Berlin 2013

The Recycling Potential of Building Materials

Consultic Marketing & Industrieberatung GmbH: Produktion, Verarbeitung und Verwertung von Kunststoffen in Deutschland 2015, summary. Alzenau 2016 Statistisches Bundesamt (Destatis): Abfallentsorgung 2015. Technical Series 19, No. 1. Wiesbaden 2017 Bundesverband Baustoffe – Steine und Erden e. V. (Eds.): Mineralische Bauabfälle. Monitoring 2014. Bericht zum Aufkommen und zum Verbleib mineralischer Bauabfälle im Jahr 2014. Berlin 2017 Fig. B 2.29: Material Cycle Status: wall, floor / ceiling, roof: outside / inside structural panels Product-specific information: Solid timber diagonal-board panel: Massivholz Junker GmbH, Nordrach, Produkt: GMF-Diagonalplatte; OSB panel, sustainable forest management: SWISS KRONO GmbH, Heiligengrabe, product: Kronoply OSB particleboard, sustainable forest management: Pfleiderer Deutschland GmbH, Neumarkt, product: LivingBoard P4 P5 P7 Fibreboard for exterior panelling: Kronospan Schweiz AG, Menznau, product: KRONOTEC MDF dampfdiffusions­ offen WP 50, DP 50; Fibreboard for exterior panelling: Fundermax Swiss AG, Kleindöttingen, product: FunderPlan Straw structural panel: Istraw – straw-based building materials, Kirchanschöring, product: Stohbauplatte E60 Loam structural panel: Thermo Natur GmbH & Co. KG, Nördlingen, product: Argaton LEHM Lehmplatte mit Jutearmierung Product-neutral information: Mantau, Udo: Holzrohstoffbilanz Deutschland, Entwicklungen und Szenarien des Holzaufkommens und der Holzverwendung 1987 bis 2015. Hamburg 2012 Buddemeier, P. (accenture AG) Sander, K. (Ökopol ­Institut für Ökologie und Politik GmbH), commissioned by the Rat für Nachhaltige Entwicklung, Zukunft Kreislaufwirtschaft: Erarbeitung einer Potenzialabschätzung von innovativen Geschäftsmodellen. 2017 Buchert, Matthias et al., commissioned by the German Federal Environmental Agency (eds.): Ökobilanzielle Betrachtung des Recyclings von Gipskartonplatten. Final report. Texts 33/2017. Umweltforschungsplan des Bundesministeriums für Umwelt, Naturschutz, Bauund Reaktorsicherheit. Dessau-Roßlau 2017 Deilmann, Clemens et al., on behalf of the Bundesinstitut für Bau-, Stadt- und Raumforschung – BBSR: Materialströme im Hochbau. Potenziale für eine Kreislaufwirt­ schaft. Zukunft Bauen, Forschung für die Praxis. Vol. 06. Ref. No: SWD 10.08.17.7-12.29. Bonn 2017 Bundesverband Baustoffe – Steine und Erden e. V. (Eds.): Mineralische Bauabfälle. Monitoring 2014. Bericht zum Aufkommen und zum Verbleib mineralischer Bauabfälle im Jahr 2014. Berlin 2017 Fig. B 2.33 Material Cycle Status: Floor Subcon­ structions Product-specific information: OSB panel: SWISS KRONO GmbH, Heiligengrabe, ­Product: Kronoply OSB Particleboard: Pfleiderer Deutschland GmbH, Neumarkt, Product: LivingBoard P4 P5 P7 Screed tile: Creaton AG, Wertingen, Product: Estrichziegel Product-neutral information: Mantau, Udo: Holzrohstoffbilanz Deutschland, Entwicklungen und Szenarien des Holzaufkommens und der Holzverwendung 1987 bis 2015. Hamburg 2012 guss I asphalt 47 technische Informationen. Gussasphalt von A – Z Bauweisen. Published by bga Beratungsstelle für Gussasphaltanwendung e. V., 2014 Müller, Anette, commissioned by the Bundesinstitut für Bau-, Stadt- und Raumforschung (BBSR): Erschließung der Ressourceneffizienzpotenziale im Bereich der Kreislaufwirtschaft Bau. Final report as of 12.2.2016. Research programme Zukunft Bau. Weimar 2016 Bundesverband Baustoffe – Steine und Erden e. V. (Eds.): Mineralische Bauabfälle. Monitoring 2014. Bericht zum Aufkommen und zum Verbleib mineralischer Bauabfälle im Jahr 2014. Berlin 2017

Fig. B 2.34 – Material Cycle Status: floor, ceiling: surfaces Product-specific information: Linoleum: Forbo Flooring GmbH, Paderborn, Product: Marmoleum 2.0 and 2.5 mm Nylon carpet tile: Desso Holding BV, A Tarkett Company, Waalwijk, Product: Desso Teppichboden-Fliese Fields Gold Product-neutral information: Mantau, Udo: Holzrohstoffbilanz Deutschland, Entwicklungen und Szenarien des Holzaufkommens und der Holzverwendung 1987 bis 2015. Hamburg 2012 Fig. B 2.42 Material Cycle Status: insulation

Fig. B 2.51 – Material Cycle Status: glazing Product-specific information: Float glass: AGC Glass UK Ltd., Rugby, product: Float Glass C2C Product-neutral information: Bundesverband Flachglas AG Troisdorf, 2017 Statistisches Bundesamt (Destatis): Abfallentsorgung 2015. Technical series 19, No. 1 Wiesbaden 2017

Product-specific data supplied by manufacturers; they refer to select products and are not applicable to the entire product category.

Product-specific information: Fibreboard insulation: UdiDämmsysteme GmbH, ­Chemnitz, product: Uditherm Sk Wood shavings insulation: Bau-Fritz GmbH & Co. KG, Erkheim, product: Wood shavings insulation: Cork insulating panel: ZIRO – Lothar Zipse e. Kfm., ­Kenzingen, product: Corktherm 040 Cork granulate: King Kork BÜS – Bürgerservice gemeinnützige Gesellschaft zur Integration Arbeitsloser mbH, Trier, product: King Kork Cellulose flakes: Peter Seppele Gesellschaft m.b.H., ­Feistritz, product: Thermofloc Hemp fibre mat: Thermo Natur GmbH & Co. KG, Nörd­ lingen, product: Thermo Hanf Premium Plus Jute fibre mat: Thermo Natur GmbH & Co. KG, Nörd­ lingen, product: Thermo Jute 100 Plus Seagrass wool: NeptuTherm e. K., Karlsruhe, product: NeptuTherm Sheep’s wool: Isolena Naturfaservliese GmbH, Waizenkirchen, product: Isolena Optimal Foam glass gravel: Misapor Management AG, Zizers, product: Misapor 10/50 Fibreglass: Knauf Insulation GmbH, Simbach am Inn, product: Knauf Insulation Holzrahmenbau-Dämmrolle Naturoll 035 Product-neutral information: WECOBIS – ökologisches Baustoffinformationssystem, retrieved on 10.09.2017 Consultic Marketing & Industrieberatung GmbH: Produktion, Verarbeitung und Verwertung von Kunststoffen in Deutschland 2015, Kurzfassung. Alzenau 2016 Bundesverband Baustoffe – Steine und Erden e. V. (Eds.): Mineralische Bauabfälle. Monitoring 2014. Bericht zum Aufkommen und zum Verbleib mineralischer Bauabfälle im Jahr 2014. Berlin 2017 Fig. B 2.46 – Material Cycle Status: seals and separating layers Product-specific information: Separation layer / trickle protection: WIKA Isolierund Dämmtechnik GmbH, Ingolstadt, Product: Graupappe 250 Trickle protection (kraft paper): Ampack AG Bautechnik, Rorschach, product: Sisalex 30 Windproofing: Villgrater Natur Produkte KG, Innervillgra­ ten, product: Impact sound insulation/windproofing Roof sealing: Derbigum Deutschland GmbH, Föhren, product: Derbipure Vapour-proofing: Korrf AG, Oberbipp, product: Aluminium Grobkorndampfsperre PE-HD deck underlay, housewrap and facade facing: DuPont de Nemours s.à.r.l., Contern, product: DuPont Tyvek Monolayer 80 PE-LD vapour barrier: ISOCELL GmbH, Neumarkt am Wallersee, product: Airstop VAP Dampfbremse EPDM roof sealing sheeting: CARLISLE Construction Materials GmbH, Hamburg, product: Hertalan Easy Cover Product-neutral information: www.alu-info.de, retrieved on 07.06.2017 WECOBIS – ökologisches Baustoffinformationssystem, Bitumen Roof Sheeting, retrieved on 10.09.2017 Consultic Marketing & Industrieberatung GmbH: Produktion, Verarbeitung und Verwertung von Kunststoffen in Deutschland 2015, summary. Alzenau 2016

101

Mono-Material Construction Markus Binder, Petra Riegler-Floors

B 3.1 Solid timber construction a The exterior walls and roof consist of doweljointed, layered hardwood boards. Residence in Stadtsteinach (DE) 2012, Rainer and Thomas Spindler b Solid wood building (walls and floors) with wood shingle cladding on the facade and roof, Strandparken residential high-rise, Stockholm (SE) 2013, Windgårdhs Arkitekter B 3.2 Frequency dependence of the sound reduction index and the location of the coincidence fre­ quency fc for different categories of building component depending on their surface mass density

102

The strict requirements currently placed on the perform­ance of components used in building shells and partitions have frequently led to the separ­ation of the required component ­functions into a plethora of successive, highly specialised shells and layers. Constructions of this type are not only perceived by their designers and builders as increasingly onerous, complicated and ­fault-prone – they also represent a barrier, or at the very least a progressively growing and therefore expensive obstacle, to separating by type the materials they employ. Tests of construction methods conducted in recent years seem to indicate the possibility of a return to mono-material approaches, i.e. buildings made of high-performance, lightweight ­concretes (insulating concrete) or of solid ­timber demonstrate how structural support and physical construction requirements can be once again united in one material. ­Furthermore, due to their clearly perceptible designs, these buildings also develop special aesthetic qualities. Recycling the utilised ­building materials becomes easier – although this requires largely avoiding additive substances. As the composite building components consist of the same basic materials, detachable ­connections are not required here. In a monomaterial construction, demolition is, as a rule, fairly simple and economically advantageous, since a complex manual dismant­ling and sorting process is required either only on a very ­limited basis or not at all. In most cases, monomaterial systems can be ­demolished less expensively using excavators. Modern physical structural requirements are largely met using the construction methods illustrated in the following pages, although a few structures must be selectively reinforced. The limitations of mono-material construction are often encountered for parts of buildings that are in direct contact with the ground or require extensive sealing, such as flat roofs. In these cases, the basic building mater­ial can often be used only for the support structure, while layers of other materials must be added to ensure the full functionality of the building parts.

Biotic Materials: Timber Timber is a renewable material that is considered among the most important of the biotic building materials. Practically all building components can be constructed entirely of this single material. The following introduces the two most common timber construction methods. Timber panel construction

The method of vapour-permeable timber panel construction common today makes it possible to build all the functional layers using timber-based materials. The supporting framework can be constructed with untreated structural timber, provided the specifications of DIN 68 800-2 are met. OSB panels affixed to the inner side act simultaneously as bracing and as a vapour barrier. Suitable materials for use as cavity insulation are either softwood fibre mats, manufactured without glue additives and stabilised only with the characteristic wood polymer lignin, or blow-in insulation consisting of wood shavings or cellulose. Planks made of medium-density fibreboard several centimetres thick seal the exterior of the building, improve ­protection against heat loss by providing an additional insulating layer over the framework and prevent cold air from flowing through the insulation. To comply with the Energy Saving Ordinance (EnEV), a supplemental layer of wood fibre insulating panels may be necessary. Further improvements to thermal insulation can be achieved by installing an interior sheathing layer that is likewise packed with fibre mats. Timber in the form of battens, sheathing or shingles is suited for weather-proofing, depending on the durability classification of the type of wood employed. In a multilayered construction, it is possible to achieve very high noise insulation and good thermal insulation even with relatively modest wall thicknesses. The construction principles mentioned here can be similarly applied to pitched roofs and floor slabs. In the latter, fibreboards can be used as impact sound insulation. Solid timber construction

In recent years, solid timber construction has seen increasingly widespread use in Germany,

Mono-Material Structures

Austria and Switzerland. In this type of construction, a number of different systems aside from cross-laminated timber panels exist for walls, floors and in part for pitched roofs, in which the individual solid wood elements are joined to one another without glues or metal fasteners and therefore represent a monomaterial approach even in their joining techniques (Fig. B 1.6, p. 44). Most of the joints between elements are effected with hardwood dowels, e.g. in dowel-laminated timber ceilings or walls of interlocking slats and in cross-laminated timber systems (Fig. B 3.1). In addition, there are various solid timber systems in which ­individual boards are attached by traditional wood joinery or by means of CNC-milled dovetailed profiles (see “Traditional wood joinery connections”, p. 49). The mutual interlocking of the individual elements renders most of these ­systems windproof. The thickness of the timber elements usually depends on the structural requirements. A thickness of 12 –16 cm is typical for load-bearing walls. Wood fibre panels attached to the exter­ior improve thermal insulation and establish windproofing for butt-jointed elements. Wea­therproofing can be achieved by mounting a rear-ventilated facade. In principle, exterior walls can be built without additional layers of wood fibre insulation. In these cases, however, they have to be made thick enough to provide the necessary thermal insulation without additional measures. The

a

b

largest available standard wall thicknesses of about 35 cm supply a thermal conductivity coefficient of 0.35 W/m2K. Walls with no cladding must be sealed against driving rain and wind by means of individually devised solutions. A few manufacturers have attempted to raise the insulating capacity of their constructions by means of milled cavities or similar measures. At present, however, the effectiveness of this method in reducing thermal conductivity is not technically approved, so it ­cannot be taken into account in any official energy use assessments.

on the other hand, it lies between 125 and 500 Hz, a range within which human hearing is very sensitive [1]. This reduces the sound reduction index even further. In situations with significant noise pollution it is important to run timely tests to determine whether the necessary amount of soundproofing is even achievable with unclad solid wood elements. Occasionally, this weakness can be compensated for through other building shell components, e.g. acoustic glazing, although only within narrow constraints. Additional layers, such as an elastic panel mounted on the interior of the wall, can yield significant improvements, although these come at the expense of structural clarity. The sound insulation of an unclad solid wood floor is likewise insufficient. Only through a combination of ballast, floating screed and, where appropriate, an elastic suspended ceiling can the minimum level of soundproofing in accordance with DIN 4109 be achieved [2].

The sound reduction index for single-leaf ­building components is primarily a function of their surface density, i.e. the heavier the component, the better the noise insulation. At only 60 to about 150 kg/m2, the surface ­densities of cross-laminated timber panels are significantly lower than those of solid masonry or concrete walls, which explains why timber’s sound insulation characteristics are comparatively poor. This effect is further ex­acerbated by another issue: depending on its stiffness, every single-leaf building component has a particular frequency at which its sound reduction index undergoes a sharp decline – the so-called coincidence (or critical) frequency (Fig. B 3.2). In high-mass walls, this lies at the lower end of or even below the ­audible frequency range and has no negative repercussions. For solid timber components,

63

125

250

500 1,000 2,000 4,000 Frequency [Hz]

fc < 200 Hz: Building component is sufficiently rigid Heavy building components, e.g. 150-mm concrete, 240-mm sand-lime brick, 240-mm solid brick

fc Sound reduction index [dB]

Sound reduction index [dB] 31.5

End of life: Using timber that can be assigned to waste wood categories A I or A II after demo­ lition allows its further use to follow a ­cascading path (see “Recycling wood as a material – waste and recovered wood”, p. 65): depending on the condition of the wood it can first be reused, then ­repurposed for manufacturing timber products (A II after the removal of coatings) and finally either composted (A I only) or thermally processed [3].

fc

Sound reduction index [dB]

fc

B 3.1

31.5

63

125

250

500 1,000 2,000 4,000 Frequency [Hz]

200 Hz < fc < 1,600 Hz: Building component is acoustically unsuited Medium-weight building components, e.g. 200-mm cross-laminated timber panel

31.5

63

125

250

500 1,000 2,000 4,000 Frequency [Hz]

fc > 1,600 Hz: Building component is sufficiently flexible Lightweight panels, e.g. 12.5-mm plasterboard panel, 4-mm glass pane

B 3.2

103

a

b

Mineral Building Materials: Loam, Brick, Aerated Concrete, Insulating Concrete

also be made from loam-based materials such as light clay bricks or plasters. Depending on their thickness, adobe or loam walls provide good to excellent sound insulation and good heat storage capacity. They also stabil­ise the indoor humidity. Since unreinforced loam building components support only compression but not tension forces, ceilings cannot be manufactured from just loam (Fig. B 3.4). Ground-contact tamped loam floors and loam seals are, however, ­feasible with restrictions.

As a rule, only exterior and interior walls can be constructed entirely from a mono-material mineral building substance. Other building components can be contructed with specific restrictions in their performance, or they must be built with the addition of complementary materials to improve their load-bearing or waterproofing characteristics, for example.

B 3.3

Loam (adobe)

Load-bearing loam walls can be constructed onsite from prefabricated adobe bricks and loam mortar or by tamping, or they can be prefabricated. The outer surface of exterior adobe brick or tamped loam walls must be protected against driving rain, since water run-off leads to erosion of the material and possible frost spalling. Pure loam plasters are not impervious to weather and therefore unsuitable for outdoor use. A limited degree of weatherproofing is achievable using embedded tile strips or trass lime moulding, which inhibit the flow of heavy rain run-off. In exterior walls of this type in which the material is exposed, a certain degree of erosion in the fine grit of the surface is taken into account and the wall thickness adjusted accordingly. Because of the relatively high thermal conduct­ ivity of solid loam, the minimum heat insulation called for in DIN 4108-2 can only be achieved by using additional insulating layers. These can

a

104

End of life: Loam and loam materials can be reused after simple processing if they do not contain additive materials (such as straw or small rock particles). However, if they do contain these additive substances, they can theoretically be composted, e.g. if the clay was extracted locally. If neither of these options apply, loam building materials of solid clay, clay with mineral additives or clay containing less than 3 % plant ­matter by mass may be dumped in class 0 waste disposal sites. “Loam materials with a larger proportion of organic additives must be processed before they can be disposed of” [4]. Brick

Today, very high-performance bricks are available for use in single-leaf masonry walls. They reach amazingly low thermal conductivity ­values down to 0.07 W/mK and simultaneously have enough load-bearing capacity for use in

b

B 3.4

B 3.3 Office building 2226, Lustenau (AT) 2013, ­Baumschlager Eberle Architekten a Construction: The 76-cm-thick brick walls ­consist of two shells made of different varieties of vertically perforated brick. b  View from outside B 3.4 Loam school building, Jar Maulwi (PK) 2013 (1st building phase), Ziegert Roswag Seiler ­Architekten Ingenieure a  Construction with unfinished walls b  Construction with plastered walls B 3.5 Aerated concrete

multistorey buildings. The high insulation effect is often reached by packing the bricks with insulating materials. However, with respect to the mono-material goal, a mixture of material types, such as a fill of polystyrene insulation, should be avoided. However, there are bricks in which similar parameter values are achieved solely through porosity and an extreme mini­ misation of the brick skeleton. As is to be expected, their compression strength is somewhat lower. Insulating bricks are approved for single-leaf walls rendered on both sides, but they have also been used as backing bricks with an exterior facing of clinker bricks for weatherproofing. ­Special attention must be given to moistureproofing in particular. Other test ­constructions, such as masonry walls consisting of highly insulating bricks on the inside interlocked with exterior clinkers, remained isolated cases because of the demanding construction requirements and unresolved questions regarding the penetration of driving rain through the horizontal joints. A combination of bricks with varying heat capacities and thermal conductivities, arranged backto-back to achieve specific thermal storage and conduction properties – as used, e.g. in Building 2226 by Baumschlager Eberle in ­Lustenau – is more promising (Fig. B 3.3). Even here, weatherproofing is achieved by means of exterior ­rendering. In the interests of mono-material ­consistency, both the inner and outer plaster in this case should be purely mineral, without a gypsum component (see “Brickwork”, p. 69f.). Mono-material brick floor slabs can be built only with great difficulty. Hollow brick panels known as Hourdis panels usually require an additional ­concrete layer and, due to their modest spans, a timber or steel support framework. In floors, expanded clay or brick rubble can serve as thermal and impact sound insu­ lation, while brick elements and ceramic dry screeds can be used in radiant floor heating systems, in which the ceramic tiles can ­simultaneously function as finished floor covering (see “Ceramic screed tiles”, p. 55 and “UFH: ceramic or lava plate”, p. 55f.). End of life: Because of the damage caused during demolition, the reuse of brick for masonry

Mono-Material Structures

a Mono-material wall construction with aerated concrete, mineral insulation and limestone-andcement rendering both outside and inside b Aerated concrete bricks as exposed brickwork: Atelier Jürgen Teller, London (GB) 2015, 6a architects B 3.6 Lightweight concrete single-family residence, Stuttgart (DE) 2014, MBA/S Matthias Bauer ­Associates a Construction of a lightweight concrete pitched roof. Because of its lumpy consistency, the ­concrete is brought in by concrete skip. b  View from inside

construction is realistic only in the case of solid bricks. For this reason, its downstream use usually takes the form of brick recyclate in other products, e.g. as a roof greening substrate. Through reprocessing and the appropriate effort, cleanly sorted, recycled brick products can be extracted, despite mortar and adhering plaster residues. If it is not reused, brick rubble can be disposed of as mineral construction waste (inert matter landfill) (see “Brickwork”, p. 69) [5]. Aerated concrete

Aerated concrete consists of sand, limestone and cement. Aluminium is used as an agent to increase the porosity. It is possible to build a mono-material mineral exterior wall of aerated concrete bricks or prefabricated slabs. Mineral panels made of the same material, but of reduced density, are suitable for use as insulation. A limestone and cement render provides weatherproofing on the outside and acts as a wall finish in the interior (Fig. B 3.5). Only the reinforcement fabric for the exterior plaster is unavoidably made of a foreign substance. However, during demolition it can easily be detached from the other materials (see “Composite insulating system on an aerated concrete exterior wall”, p. 109). Aerated concrete cannot be used in monomaterial floor and roof construction; only the support structure can consist of prefabricated aerated concrete slabs. Because of their high porosity, aerated concrete building components have a very low thermal conductivity value; depending on gross density and compression strength, it varies between 0.08 and about 0.20 W/mK [6]. As a consequence, typical current insulation requirements can be met with single-leaf constructions in many cases. As is the case for other highly porous building bricks, the disadvantage is low heat capacity, which means special attention must be paid to protection from heat during summer months. Due to their modest weight, the noise insulation properties of aerated concrete building ­elements are limited, even though they possess relatively high inner damping, which is included in the sound reduction calculations [7]. De-

B 3.5

a

b

pending on the ambient noise situation, the use of shells may be necessary. Single-leaf aerated concrete partition walls are not an option.

standard concretes, the thickness of load-­ bearing building elements needs to be substantial; exterior walls of 50 – 70 cm thickness are not at all unusual. This has positive effects on both the sound and thermal insulation ­characteristics. Nevertheless, with the certified thermal transmittances of the products currently avail­able on the market, the achievable U-values lie only in the 0.50 to 0.65 W/m2K range. Interior walls and floors in lightweight concrete structures are usually made from normal ­concrete. Their storage mass for the equilibration of temperature fluctuations is therefore ­typically high.

End of life: Aerated concrete building elem­ents can be reused if they are dismantled without damage. In its 100 % mono-material form, recycled aerated concrete can replace the usual aggregates in the manufacture of new products. Depending on the new product requirements, the recycled portion can comprise anything from 15 to 40 % of the new product’s mass [8]. Reuse outside of construction is also possible (see “Aerated concrete masonry”, p. 70). The material can be disposed of as mineral construction waste [9]. The use of lightweight rock granules such as perlite, pumice, expanded clay and foam glass gravel now makes it possible to produce very lightweight concretes with thermal conduction values that sometimes fall significantly below 0.3 W/mK (Fig. B 3.6). For this reason, these are also referred to somewhat imprecisely as insulating concretes. Because of their compos­ ition and their very low gross density, insulating concretes do not fall under the usual concrete standards. Their properties must therefore be certified through a National Technical Approval process. Since the compression strength of lightweight concrete is significantly lower than that of

End of life: An aggregate material of foam glass or expanded clay cannot be separated by type from the other concrete components. Because of its reduced load-bearing capacity, the concrete portion is generally ineligible for the typical uses either as a supporting layer in the subbase or as an additive for recycled concrete. The reclamation of the glass foam gravel and the reuse of the expanded clay are both prevented by the adhering concrete residues. The material is therefore disposed of as mineral construction waste [10]. Hydrophobisation, e.g. with poorly degradable silicone resins, must be avoided. Silicone resins are not approved for landfill disposal. If they do end up in a landfill as residues, the products of their decomposition contaminate the landfill run-off [11].

a

b

Lightweight concrete (insulating concrete)

B 3.6

105

Mono-material use possible Mono-material use possible Mono-material use possible with restrictions Mono-material use possible with restrictions Mono-material use not possible Mono-material use not possible Timber Timber

Conclusion and Prospects

Loam Loam

Current research approaches and the further development of existing construction methods demonstrate the ways in which the structural and physical characteristics of mono-­ material constructions can be further improved. So-called infra-lightweight concrete with reliably low thermal conductivity values of less than 0.2 W/mK makes single-leaf concrete walls an option even for the nearly-zero energy houses built to today’s standards [12]. Gradient concretes, whose composition varies over the cross-section of the building component, offer new possibilities for well-insulating and simultaneously highly load-bearing building components [13].

Brick Brick

The use of mineral building materials can often simplify compliance with fire safety and sound insulation requirements, but in common building practice it almost always implies downcycling – except in the case of loam. Because of the purity of type inherent in mono-material constructions, the reuse and recovery of mineral materials is often possible before eventual ­disposal. Thanks to its increasing economic importance, solid timber construction has enormous potential for further development. In addition, its fast assembly times and financial advantages make its future spread beyond the traditional timber construction regions a highly likely prospect.

Lighweight concrete Lighweight concrete

A dogmatic adherence to the principles of mono-material construction sometimes makes it difficult to meet all structural and physical demands to an equivalent degree (Fig. B 3.8). An individual, targeted approach, in which the chosen main material is complemented by other substances that do not pose obstacles to recyclability – from the same waste fraction, if possible – therefore represents a sensible alternative to a forcible mono-material concept.

Aerated concrete Aerated concrete

B 3.7

106

Notes:   [1] Bednar, Thomas; Vodicka, Michael; Dreyer, Jürgen: Entwicklung im mehrgeschossigen Holzbau am Bei­ spiel des Schallschutzes der Trenndecken. Annual Conference of the Österreichische Physikalische Gesellschaft (ÖPG) Fachausschuss Akustik. Graz 2000   [2] Numerous floor constructions and their parameter values can be found in: Holzforschung Austria Öster­ reichische Gesellschaft für Holzforschung (Eds.): Deckenkonstruktionen für den mehrgeschossigen Holzbau. Schall- und Brandschutz. Vienna 2015 (HFA-Schriftenreihe Vol. 20)   [3] Verordnung über Anforderungen an die Verwertung und Beseitigung von Altholz (Altholzverordnung – AltholzV), 03/2003, www.gesetze-im-internet.de/ altholzv. As of 29.09.2017 www.wecobis.de/bauproduktgruppen/bauprodukte-aus-holz.html. As of 29.06.2017  [4] www.wecobis.de/bauproduktgruppen/massivbau­ stoffe/lehmbaustoffe.html – Life cycle /subsequent use. Retrieved on 29.06.2017  [5] www.wecobis.de/en/bauproduktgruppen/massiv­ baustoffe/ziegel.html. Retrieved on 28.8.2017 www.wecobis.de/bauproduktgruppen/massivbau­ stoffe/ziegel/porosierte-ziegel.html. Retrieved on 28.8.2017   [6] Bundesverband Porenbeton (Eds.): Porenbeton ­Bericht 19. Wärmeschutz und Energieeinsparung – EnEV 2014. Berlin 2014   [7] DIN 4109-32:2016-07 Sound insulation in buildings part 32: Data for verification of sound insulation (component catalogue) – solid construction   [8] Product information Xella Deutschland GmbH, Duisburg, 8.12.2016, www.ytong-silka.de/recycling.php. Retrieved on 06.09.2017  [9] www.wecobis.de/bauproduktgruppen/massivbau­ stoffe/porenbeton.html. Retrieved on 14.07.2017 [10] www.wecobis.de/bauproduktgruppen/massivbau­ stoffe/beton/frischbeton.html. Retrieved on 06.09.2017 www.wecobis.de/bauproduktgruppen/daemmstoffe/aus-mineralischen-rohstoffen/schaumglas.html. Retrieved on 06.09.2017 www.wecobis.de/bauproduktgruppen/grundstoffegs/gesteinskoernung-gs/industriell-hergestelltegesteinskoernungen/blaehton-gs.html. Retrieved on 06.09.2017 [11] www.wecobis.de/bauproduktgruppen/oberflae­ chenbehandlungen/farben-lacke-lasuren/silicon­ harzfarben.html. Retrieved on 06.09.2017 [12] Schlaich, Mike; Lösch, Claudia; Hückler, Alex: Infraleichtbeton Stand 2015. In: Holschemacher, Klaus (Ed.): Betonbauwerke für die Zukunft. Berlin 2015, p. 93 –104 [13] Heinz, Pascal; Herrmann, Michael; Sobek, Werner: Herstellungsverfahren und Anwendungsbereiche für funktional gradierte Bauteile im Bauwesen. Final report of the research project funded by BBSR as part of the research initiative Zukunft Bau. Stuttgart 2011 https://www.irbnet.de/daten/baufo/20128035526/ F_2811_Abschlussbericht.pdf

Mono-Material Structures

B 3.7 Comparison of the mono-material construction ­potential of several different building materials B 3.8 Thermal conductivity and additional characteristics of selected materials B 3.9 U-values and sound reduction indices of selected mono-material exterior wall constructions Thermal conductivity λ [W/mK]

Specific heat capacity [J/kg K]

Water vapour diffusion resistance factor, µ-value (moist / dry)

Gross density [kg/m3]

0.12 ... 0.13 0.18 0.13 (0.08) 0.034 ... 0.063 0.13

1,600 1,600 1,600 ≥ 1,700 1,700

20 /50 50 /200 > 20 /50 1/2 ... 3/5 30 /50

450 ... 500 700 450 ... 500 40 ... 250 650

0.91 ... 1.40 0.47 ... 1.40 0.17 ... 1.40

1,000 1,000 ≥ 1,000

5 /10 5 /10

1,800 ... 2,200 1,200 ... 2,200 600 ... 1,200

0.81 ... 1.4 0.50 ... 1.4 0.09 ... 0.29

1,000 1,000 1,000

50 /100 5 /10 5 /10

1,800 ... 2,400 1,200 ... 2,400 550 ... 1,000

0.39 ... 1.35 (0.17)

1,000

70 /150

800 ... 2,000

0.12 ... 1.2

1,000

5 /15

400 ... 2,000

0.08 ... 0.25

1,000

5 /10

350 ... 800

Timber and timber materials Lumber / coniferous Lumber / hardwood Cross-laminated timber Softwood fibre mats OSB panels Loam materials Tamped loam Adobe bricks Lightweight loam bricks Brickwork including mortar joints Clinker Solid brick Lightweight vertically perforated brick (unfilled) Lightweight concrete With closed joints With open-pore concrete joining and porous aggregates Aerated concrete Block masonry

Measured values λB in accordance with DIN 4108-4:2017, DIN EN ISO 10 456:2010, loam construction regulations or National Technical Approvals. The values in parentheses are manufacturers’ claims based on their own measurements as well as values from research and development projects.

Type of exterior wall

Total wall thickness [cm] Sound reduction index R'w [dB] Thermal transmittance U [W/m2K] Heat capacity 1) [Wh/m2K]

Timber beam wall with 40-mm interior sheathing and exter­ ior curtain wall facing

Solid timber wall with weather­ proofing

Solid timber wall with 12-cm softwood fibre insulation and weather­proofing

Tamped loam wall

Masonry wall of highly porous bricks with rendering on both sides

Lightweight ­concrete wall

B 3.8

Aerated concrete wall with rendering on both sides

31

43

38

45

39

60

39

42 – 45

39

45

57

48

58

47

0.20

0.34

0.24

2.1

0.24

0.6

0.24

6

8

8

20

8

12

7

All values are approximate, based on typical material parameter values.

1) 

Calculated in accordance with DIN EN ISO 13 786 over the period of 1 day

B 3.9

107

Can Loop Potential Be Measured? An Analysis Using Facade and Roof Coverings as Examples Anja Rosen

Loop Potential as a New Architectural ­Parameter If the enormous consumption of resources in construction is to be reduced to a sustainable level, construction will have to undergo a paradigm shift. This will require the creation of a political framework, but it will also be necessary to conceptualise the loop potential of buildings by way of a design parameter. In order to incorporate the principles of recyc­ling-friendly construction, new, quantitative evaluation ­criteria will be needed with which to measure the resource efficiency of buildings and structures.

factors, the bulk of the demolition cost depends largely on the amount of human and machine labour required (see “Dismantling, Recovery and Disposal in Construction”, p. 16ff.). In order to study the measurability of demolition costs, the Bergische Universität Wuppertal, in collaboration with training centres and ­man­u­facturers, built and then dismantled a series of sample facade and roof constructions. In anticipation of the disassembly phase, ­special efforts were made in the design of the constructions to use detachable material connections whenever possible so as to sub­ sequently facilitate high-quality separation by type. The experiments are elucidated below, using nine facade and roof constructions as examples.

Criteria for the Assessment of Loop ­Potential Facades The certification systems introduced in the chapter “An Overview of Rating ­Systems” (p. 24ff.) include the ease of dis­assembly and recyclability of structures to a point, although only in a qualitative way. A method for the quantitative assessment of loop potential is ­currently being developed in a doctoral thesis at the Bergische Universität Wuppertal [1] (see also “Assessment of Loop Potential”, p. 114ff.). The systematic approach encompasses not only the technical material aspects but also economic considerations, and is ­predicated on the assumption that, according to the laws of the free market, a high-quality recovery programme will only be implemented if there is profit in it. For a qualitative assessment, therefore, there are three ­critical factors apart from the mass of the resource itself: the technical or natural recycling potential of the material, the value of the reclaimed ­substances and the effort involved in selective demolition. The chapter “The Recycling Potential of Building Materials” (p. 58ff.) introduces the recycling potential of individual substances in terms of their Material Cycle Status. The value of the materials is determined by the revenue generated from their recovery or the cost of their disposal [2]. Aside from construction site-specific 108

All the experimental stands for the facades were fabricated in the same proportions and sizes by various manufacturers and training facilities. The exception was the post-andbeam facade, for which a manufacturer’s test stand was used. Even though the facades were adapted to the given support structures, the focus of the experiment was always on the facade cladding and not the ­support element. Facing brick shell on a load-bearing exterior wall

The recycling potential of fired bricks is limited (see “Mineral materials: masonry materials, concrete”, p. 69ff.). The material is, however, notable for its longevity and its modular con-

B 4.1

Can Loop Potential Be Measured?

B 4.1 Reusable: water-struck clinkers on a solid exterior wall, lime mortar above, cement-lime mortar below B 4.2 Easily repaired: rear-ventilated curtain facade on a solid exterior wall B 4.3 Homogeneous: composite insulating system of mineral insulating panels with lightweight render on aerated concrete B 4.4  Timber cladding on a timber beam exterior wall

struction method. The focus at two of the test stands was therefore placed on the reusability of brick facades. The first test stand shows a solid clinker facing shell, half of which was jointed with eminently hydraulic lime mortar and the other with cement-lime mortar. On the second stand, bricks were dry-laid and attached to the subconstruction with stainless steel anchors (Fig. B 4.1; Fig. B 4.9 Nos. 1 & 2, p. 112 as well as Fig. B 1.20, p. 50). The ­central question in this experiment was how much time and energy would be required to disassemble the facade without damage. While the dry-laid facade including the insu­ lating shell was dismantled quickly and nondestructively using only simple tools, the real surprise came with the mortared shell: even though the cement-lime mortar was expected to have formed a tighter bond than are highly hydraulic lime ­mortar, it turned out to be possible to separ­ate the bricks in both wall types – with an approximately equal, though considerable, investment of time and energy – with very little waste, by means of a hydraulic chisel, so that in both cases the bricks were recovered with only negligible adhesions. The reason for this is the use of high-quality water-struck clinkers with very low water absorption capacity. Ventilated curtain facades on a load-bearing exterior wall

Rear-ventilated curtain facades can be mounted on a supporting wall in many different ways. On one of the test stands, two different cladding materials were affixed to an alumin-

B 4.2

ium subconstruction on a solid wall by different methods (Fig. B 4.2; B 4.9 Nos. 3 – 7, p. 112f.) in the following combinations: •  fibre cement panels with agraffe fasteners •  fibre cement panels with visible rivets •  glued fibre cement panels •  clamped aluminium sheet cassettes The mounting systems were adapted to two ­ ifferent insulating materials: for the mineral d wool insulating mats, the mounting rails were attached to the supporting wall with metal angles and brackets, while anchored brackets were used with the foam glass panels. Attaching the insulation to the support wall with plate anchors or claw plates obviated the need for an adhesive. The focus of the study was the effort required to disassemble the entire construction, including cladding, subconstruction and insulation. Because of the limited recycling potential of the fibre cement panels, the goal was to remove them with as little damage as possible so that they could be reused. The results of the test showed that the agraffefastened fibre cement panels, combined with mineral wool insulation and wall brackets, were most easily and quickly removed without damage. The glued-on panels, on the other hand, could be loosened with force, but the residue of polyurethane adhesive that remained on the joining elements was difficult to remove. The dismantling of the aluminium cassettes clamped to a modular click rail required a ­certain amount of practice in the use of the

B 4.3

manufacturer-provided tools; the time spent on this would become negligible in large-scale applications. Composite insulating system on an aerated concrete exterior wall

A conventional composite insulating system comprises a number of mutually bonded ­layers of inhomogeneous materials, which makes recycling impossible. One of the test stands was therefore used to experiment with a construction that optimised material homogeneity. In this construction, pictured in Fig. B 4.3 and B 3.5 a (p. 105), the supporting structure is an aerated concrete exterior wall clad with an insulating panel made of the same substance in a substantially more porous version. The mortar used to glue on the insulating panels and the outer render are likewise made of the same material. The only foreign element is a plaster-fibreglass mesh. The test results showed that the plaster-and-mesh layer could be easily cut into and torn off, during which some of the plaster and the fouled mesh went to waste. The wall and the insulation were torn down together by machine in very little time and with comparatively low energy expend­ iture and sent on for recovery. Regarding loop suitability, it is important to remember that the recycling of mono-material demolition waste is possible, but its us­­ ability as a secondary substance is limited to a certain percentage of the newly produced material (Material Loop Potential in “Examples of Materials: Fundamentals and Evaluation”, p. 63).

B 4.4

109

Timber cladding on a timber beam exterior wall

The concept for the construction of this test stand was also predicated on the use of homogeneous materials for eventual disassembly. Thus, the materials used were largely from renewable resources that can be reutilised in a one- or multi-step cascade within the biotic loop (see “The recycling potential of biotic materials”, p. 60f.). A timber beam supporting frame was clad in untreated larch wood slats, of which half were tongue-and-groove profiles fastened with hidden screws and half were rhombus profiles with visible screw attachments (Fig. B 4.4, p. 109 and B 4.9 Nos. 9 & 10, p. 112f.). Apart from the binders used in the ­timber materials, the only foreign substances were a windproofing sheet and plastic weather stripping as well as an aluminium ­corner guard. The dismantling process turned out to be quite time-consuming because of the many screw attachments. However, these allowed the untreated timber slats (rated as A1 quality by the German Waste Wood Ordinance, see “Recycling wood as a material – waste and recovered wood”, p. 65) to be ­separated cleanly by type from the other wood-based ­elements. As a consequence, the problemfree reuse of the A1 timber is possible, while the wood-based elements, some of which had sticky residues (adhesive strip on OSB), are more likely to be earmarked for energy generation. In a real demolition scenario, the detaching of the screw joints may only be possible to a limited extent because of weathering. A sep­

B 4.5

110

B 4.5 High-value materials: post-and-beam facade with aluminium profiles B 4.6 Long-lasting: slate tiles on a pitched roof B 4.7 Closed-loop construction: standing seam zinc sheet on a pitched roof B 4.8 A comparison of facade and roof cladding loop parameters Facades: 1 Clinker facade, stainless steel brackets, rock wool 2 Brick, dry-laid system, stainless steel anchors in timber subconstruction, hemp ­insulation 3 Fibre cement with agraffe fasteners, riveted ­aluminium subconstruction, foam glass 4 Fibre cement with agraffe fasteners, riveted ­aluminium subconstruction, mineral wool 5 Fibre cement riveted onto aluminium subconstruction, mineral wool

  6 Fibre cement glued onto aluminium ­subconstruction, mineral wool   7 Aluminium sheet cassettes clamped onto riveted aluminium subconstruction, foam glass   8 Mineral-based composite thermal insulating ­system   9 Timber slat cladding, fibreboard insulation 10 Rhombus timber slats, fibreboard insulation 11 Aluminium post-and-beam facade, insulating glazing Roofs: 12 Inverted roof, bitumen sealing sheeting, foam glass, gravel 13 Flat roof seal of renewable materials, fibreboard 14  Pitched roof, slate tiles, fibreboard 15  Pitched roof, zinc sheet, fibreboard

aration by type is nevertheless fairly easily accomplished by sawing, with destroying of the ­connecting elements.

The window profiles were sent to an aluminium recycling facility in which manually nondetachable foreign bodies are mechanically separated from the metal. The aluminium undergoes high-quality recycling, while the plastics are thermally processed. Glass and EPDM sealing materials can be exploited, although for the most part at a lower quality and as a restricted secondary proportion of the new product (see Material Loop Potential in “Examples of Materials: Fundamentals and Evaluation”, p. 63 and “Openings and Glazing Units”, p. 95ff.).

Post-and-beam facade

A post-and-beam facade is usually a mostly transparent, sectioned exterior wall, the complexity of which becomes apparent only in detail. The necessary seals of the profiles and glazing against moisture and air exchange are often made of materials containing problematic substances (e.g. plasticisers). Plastic insulators in profiles and metallisation on glass are employed in order to comply with stringent thermal insulation requirements. Projections and recesses in a sectioned facade demand complicated detailed solutions, usually involving bonded seals. On the test stand the construction was therefore optimised to minimise its complexity (Fig. B 4.5 and B 4.9 No. 11, p. 112ff.). Posts and beams as well as window frames and casements were made of Cradle-to-Cradle-certified aluminium profiles (see “The materials cycle concept in the ­Cradle-to-Cradle system”, p. 29). In the dismantling test, conditions were similar to those on a realistic construction site and the same tools and machines were used that are normally available on-site, such as, for example, a work platform in place of scaffolding, and crane-driven glass removal with vacuum suction frames. The test showed that the individual pieces of the post-and-beam facade could be disassembled in a relatively short time with little energy expenditure and sorted into their sep­ arate waste fractions.

B 4.6

Roof Coverings When dismantling roofs, glued roof seals ­present the greatest obstacles to the clean separation of layers by type. The experiments therefore focused on constructions that had been optimised for simplicity or those in which adhesives could be avoided. Inverted roof with bitumen seal and foam glass ­insulation

An inverted roof combines two layers – the vapour proofing and the seal – found in a ­conventional roof construction into a single layer beneath the insulation. In this case the vapour barrier already represents a high-­ quality seal [3]. On the test stand, a bitumen underlay acting as this double-functional layer was loosely laid on the supports and heat-sealed only at overlapping seams, while a second layer was then heat-welded

B 4.7

Can Loop Potential Be Measured?

12

25

10

20

8

15

6

10

4

0

0.05

0.30 0.04 0.25 0.03

0.20 0.15

0.02

0.01

0.05

0 1 2 3 4 5 6 7 8 9 10 11

0.35

Transparent building component

0.10

2

5

Cladding

Recovery revenues (+) and waste disposal costs (-) [€/m2]

50

Subconstruction Energy expenditure during dismantling [MJ/m2]

Manual work during dismantling [min/m2]

Insulation

1 2 3 4 5 6 7 8 9 10 11

37 7

12 13 14 15

Ballast 8 7 6 5 4 3 2

6 5 4 3

1 0 -1 -2

2 1 0 -1

-3 -4 -5

-2 -3

0

0 12 13 14 15

Seal/sheet

1 2 3 4 5 6 7 8 9 10 11

12 13 14 15 B 4.8

to the entire surface of the underlying sheet. Closed-cell foam glass panels made from waste glass were used as insulation. Since these do not absorb water nor swell or shrink, they prevent the formation of thermal bridges. A layer of gravel, separated from the insulation by a water-diverting fleece, was spread to protect against buoyancy and wind suction. The roof construction can be dismantled manually with very little effort. The bitumen sheet material can be readily recycled if no metal inlay is used (no vapour-inhibiting function). The manufacturer has established a take-back system for this purpose: old sheets of plastomeric bitumen (with an admixture of atactic polypropylene – APP) are collected, shredded, melted down and reprocessed into new sheeting (Fig. B 4.10 No. 12, p.112). Sealing a flat roof with renewable materials

As an alternative to fossil fuel-based roof sealing sheeting, a Belgian company has developed seals that consist primarily of vegetable oil and pine resin (see “Plant-based roof sealing sheeting”, p. 92). According to the manufacturer’s claims, the Cradle-to-Cradle-certified roof sheeting, with a reinforcing polyester and fibreglass mat insert, can be fully recycled. Because of the innovative approach, there is as yet no applicable, generally recognised verification process in place in Germany, so that the product does not yet have a National Test Certificate (allgemeines bauaufsichtliches Prüfzeugnis (abP)). In general, the manufacturer's installation ­recommendations indicate that the sealing sheet is to be welded on across its entire ­surface. On the test stand, however, a mechanical fastening method was also tested in order to optimise separability by type. In this case, an underlay was joined to the substrate with plate anchors driven straight through crushresistant wood-fibre insulation panels, whereupon an upper layer was full-surface welded over it. The dismantling test revealed that the anchoring presented an obstacle, since the plate anchors were hidden by the upper ply and

could not be manually unscrewed. On a demolition site, a realistic approach would be disassembly using a mechanical grab. Since the sealing sheet is not available in a vapour-proof version, a commonly used bitumen sheet with metal inlay was loosely laid as a vapour barrier. This could be removed ­without adhesions, but can only be thermally reprocessed with the loss of the aluminium inlay (Fig. B 4.10 No. 13, p. 112). Coarse-grained aluminium foil sheeting is recommended as a vapour barrier as a recyclingfriendly alternative (see “Detailed Catalogue: Roof construction”, p. 160). Slate tiles on a pitched roof

Pitched roofs are most commonly covered with mineral materials. However, the recyc­ lability of ceramic tiles, concrete roofing tiles and fibre cement shingles or slate tiles is ­limited (see “Mineral materials”, p. 76ff.). The goal of this demolition test stand was the ­damage-free dismantling of a roof covered in high-quality slate tiles for reuse (Fig. B 4.6 and B 4.10 No. 14, p. 112). The disassembly of the insulation and sheathing was not part of the test. In order to compare the overall ­construction with the flat roof ­experiments, some of the results from the ­dismantling of the “Timber cladding on a ­timber beam exterior wall” (p. 110) were ­substituted. A comparison of the conventional demolition process and manual disassembly revealed a significant relationship between the effort involved in dismantling and the avoidance of damage. The manual disassembly took twice as long and left 75 % of the nailed tiles undamaged, while standard demolition destroyed about 90 % of them. Since mineral roofing materials are subject to weathering, their reusability is limited. For refurbishments, however, reuse represents a resource-conserving option. Double standing seam zinc sheet on a pitched roof

Metal roofing represents a very long-lasting, recycling-friendly alternative to mineral pitched roof coverings. A standing seam sheet is a sheet made up of interlocking, homogeneous

bands of zinc or copper. The double standing seam roof consists of standing seam ­panels (metal sheet profiles) with vertical legs along the sides, which are double-crimped with those of the adjacent panel. The roof ­covering is attached with special metal fas­ teners that are screwed into the sheathing near the edges and that become an intrinsic part of the ­system when the seams are sealed. The dismantling on the test stand (Fig. B 4.7 and B 4.10 No. 15, p. 112) proceeded with the goal of salvaging the metals with no concern for the destruction of the sheets themselves, since single-substance metals can be multiply recycled by melting them down. The time spent on demolition was consequently very short. Conclusions Almost all constructions that were tested and that are compared in the charts in Figs. B 4.9 and B 4.10 (p. 112) can be recommended for urban mining-friendly building. The exception is the ventilated curtain facade with the glued fibre cement panels, since the glue adhesions would have to be removed with a disproportionate amount of effort, and even then their material recovery would be of low quality (downcycling). Figures B 4.8 to B 4.10 (p. 112f.) show the parameters by which the closed-cycle potential of constructions can be measured: at the construction level they reflect the (human labour and energy) investments of the dis­ mantling process as well as the disposal costs or recovery revenues [4], while at the mater­ ial level they reflect the associated recycling process. The graphic comparisons make important aspects of the economic feasibility of selective dismantling readily recognisable: The effort required for dismantling is closely related to the value of the materials. A high degree of disassembly effort is economically justifiable when it results in recovery revenue or waste disposal savings. The greater the ­predicted recovery revenue or the smaller the waste disposal costs, the more profitable the 111

Facades

No. Construction

Wall thickness [mm] Thermal conductivity U [W/m2K] Manual work during ­dismantling [min/m2]

1 240-mm load-bearing ­exterior wall 160-mm anchored mineral wool   40-mm air layer 115-mm water-struck ­clinkers on stainless steel brackets; half bonded with lime mortar and half with lime-cement mortar 555

Energy expenditure during dismantling [MJ/m2]

2 240-mm load-bearing ­exterior wall 200-mm hemp insulation packed between timber ­battens   15-mm MDF panel   40-mm air layer   90-mm dry-laid brick

3 4 240-mm load-bearing 240-mm load-bearing ­ xterior wall e ­exterior wall  nchored 160-mm foam glass on claw 160-mm a mineral wool plates   12-mm fibre cement ­panels,   12-mm fibre cement ­panels, agraffe agraffe-fastened ­fastened to alumin­ to aluminium ium subconstruc­subconstruction tion on wall angles on stainless steel brackets 530 530

585

5 240-mm load-bearing ­exterior wall 160-mm anchored mineral wool   12-mm fibre cement panels visibly riveted onto aluminium subconstruction on sliding point bracket 485

0.20

0.20

0.20

0.20

0.20

50.7

13.6

13.8

7.7

10.6

0.21

0.13

0.32

0.23

0.21

-0.76

+1.96

+1.66

-0.15

Recovery revenues (+)  +35.83 Waste disposal costs (-) [€/m2] Material Loop Potential, cumulative Material-Loop-Potential, 1% ‡ Reuse kumuliert ‡ Recycling 16% Wiederverwendung ‡ Downcycling 3% Recycling Energy recovery ‡  Downcycling of renewable resources ‡  Energy recovery Thermische Verwertung of fossil materialsRohstoffe Nachwachsende 80 %   Waste / landfill disposal Thermische Verwertung

1%

8%

0.5% 9% 3%

15.5%

15 % 36%

76 %

10 % 4%

19 %

26%

48.5%

0.5 %

67 %

62%

Fossile Rohstoffe Entsorgung/Deponierung

B 4.9

Roof

No. Construction

Material-Loop-Potential, kumuliert

1% 12

16 % Wiederverwendung  50-mm gravel 3% Recycling  5-mm PP fleece Downcycling 2≈ 140-mm loosely laid foam glass Thermische Verwertung ­insulating panels, upper Nachwachsende Rohstoffelayer glazed 80 %   5-mm fully welded bitumen Thermische Verwertung ­sealing sheet Fossile Rohstoffe   5-mm bitumen sealing sheet, Entsorgung/Deponierung only seams welded Material-Loop-Potential, Material-Loop-Potential, 2 % graded screed (homogeneous kumuliert kumuliert 6,5 %% Material-Loop-Potential, with slab: not tested) Material-Loop-Potential, composite6,5 Wiederverwendung Wiederverwendung  200-mm reinforced concrete slab kumuliert kumuliert 7,5% 7,5% 6,56,5 %% Recycling Recycling Thermal conductivity Wiederverwendung Wiederverwendung 7,5% 7,5% 0.14 2 U Downcycling [W/mRecycling K] Downcycling Recycling Manual work during Thermische Thermische Verwertung Verwertung Downcycling Downcycling 4.9 2 ­dismantling [min/m ] Nachwachsende Nachwachsende Rohstoffe Rohstoffe 86% 86% Thermische Verwertung Thermische Verwertung EnergyNachwachsende expenditure duringRohstoffe Nachwachsende Thermische Thermische Verwertung VerwertungRohstoffe 86% 86% 0.00 dismantling [MJ/m2] fossile fossile Rohstoffe Rohstoffe Thermische Verwertung Thermische Verwertung Recovery revenues (+)  Entsorgung/Deponierung Entsorgung/Deponierung fossile Rohstoffe fossile Rohstoffe -1.22 Waste disposal costs (-) [€/m2] Entsorgung/Deponierung Entsorgung/Deponierung Material Loop Potential, cumulative Material-Loop-Potential, ‡ Reuse kumuliert 6.5 % ‡ Recycling Wiederverwendung 7.5% ‡ Downcycling Recycling ‡ Thermal recovery Downcycling of renewable resources ‡ Thermal recoveryVerwertung Thermische of fossil materials Nachwachsende Rohstoffe 86%  Waste / landfill Thermischedisposal Verwertung fossile Rohstoffe Entsorgung/Deponierung

112

1%

0,5% 0,5 % 9% 10 % 8% 13 14 15 15,5% 3% 4%   1-mm double standing seam 7-mm slate tile, nailed 2≈ 3-mm  renewable material sealing sheet, 15% zinc sheet  0.5-mm PP fleece underupper ply fully welded, lower ply 19 % 26% 48,5%   0.5-mm PP fleece underlay with lay with mechanically fastened TEEE membrane, TEEE membrane, 50 –170-mm loosely laid graded fibreboard 36% clamped ­insulation 62 %clamped 67 % 76 %   20-mm MDF panel 20-mm MDF panel 160-mm loosely laid fibreboard insulation   40-mm fibreboard insulation 40-mm fibreboard 3.5-mm bitumen vapour-proofing sheet, 220-mm wood fibre insulation ­insulation only seams welded packed between rafters 220-mm wood fibre insu­ 200-mm reinforced concrete slab 0,2% 0,2% lation packed 0,70,7 %% ­between 0,2% 0,2% rafters 0,70,7 %% 10% 10% 11,3% 11,3% 30,7% 30,7 % 4%4% 10% 10% 11,3% 11,3% 14% 14% 30,7 % 30,7 % 4% 4% 0.15 0.16 0.16 14% 14% 86% 86%

6.1 0.00 86% 86%

19% 19%

55% 55% 19% 19%

11.0 55% 55% 0.04

-2.45

-0.96 0.2%

10% 4%

86%

11.3%

8.4 68,7 68,7 %% 0.04 68,7 %% 68,7 +6.97 0.7 % 30.7 %

14% 19%

55%

68.7 % B 4.10

%%

Can Loop Potential Be Measured?

6 7 240-mm load-bearing 240-mm load-bearing ­ xterior wall e ­exterior wall 160-mm foam glass on claw 160-mm mineral wool, plates ­anchored   12-mm fibre cement glued    1-mm aluminium sheet ­cassettes on click onto aluminium rail, aluminium subconstruction on ­subconstruction sliding point rail on stainless steel brackets 485 530

8 240-mm aerated concrete    5-mm lightweight mortar 100-mm mineral insulating panel    5-mm lightweight mortar with fibreglass ­reinforcement    2-mm lightweight mortar surface plaster 352

9   15-mm OSB panel 180-mm solid timber with flexible wood fibre insulation   20-mm fibreboard panel   0.5-mm PP fleece with TEEE membrane, stapled   30-mm black-glazed spruce boards  27-mm larch wood cladding 273

10   15-mm OSB panel 180-mm solid timber with flexible wood fibre insulation   20-mm fibreboard panel 0.5-mm PP fleece with TEEE membrane, stapled    30-mm black-glazed spruce boards   30-mm rhombus slats 273

0.20

0.20

0.19

0.21

0.21

8.5

20.2

0.6

11.4

12.2

0.10

0.21

0.09

0.15

0.17

-1.20

+4.07

-1.86

-0.93

-0.92

1% 1%

0.5 0.5 0.5 %%0.5 %% 1919 %%

135 0.80 8.8 Not including the energy 0.09 expenditure of the aluminium recycling plant

+4.76

0.4 0.4 %%

15% 15%

2323 %%

7676 %%

85% 85%

6.3 6.3 %% 27.3 27.3 %%

39.5% 39.5%

39% 39% 81% 81%

1% 1%

11   50-mm aluminium profiles with insertion ­elements   42-mm triple glazing   40-mm steel tubing 150-mm steel angle ­brackets, sealing profiles and packed EPDM foils

60% 60%

59.5% 59.5%

6666 %%

B 4.9 Overview of the tested facades. The load-bearing economically profitable relationships between dismantling process tends to be. It is worth elements are indicated in grey in drawings and dismantling work and recovery revenue. doing significant dismantling work if the saltext since they are not included in the data. An examination of the energy expenditures vaged materials are themselves valuable. B 4.10 Overview of the tested roof coverings. The loadin particular reveals that constructions involvRecovery revenues can be expected when bearing elements are indicated in grey in drawings ing riveted joints require a relatively large demand, i.e. a market, exists for the waste and text since they are not included in the data. energy input during the dismantling process. materials. This is the case for all scrap metal 1% 1% Notes: 1% 1 % 0,5% 0,5% 0,5% 0,5% 0,4 % 0,4 % The use of clamping or click-lock systems and high-quality clinker bricks, for example. % 0,5% [1] Rosen, Anja: Entwicklung einer Systematik zur quan­ 10% 10% is more suited to 15% disassembly-friendly con15% 19% 19% titativen Bewertung des Kreislaufpotenzials von Bau% 4% 23% 23% struction. Thus, dismantling a mortared masonry curtain 6,3 % 6,3 % konstruktionen in der Neubauplanung. Bergische 39,5%39,5% 39% 39% 27,3 %27,3 % % 19% ­Universität Wuppertal (ongoing doctoral dissertation) The proportionate end-of-life paths of the entire facade may be a very work-intensive process, [2] Based on research personally conducted at 28 waste structure are a function of the recycling potenbut it can still be profitable, since it saves and recycling facilities throughout Germany. As of 67% 67 % waste disposal building materials. This costs 81% 81%and a market for high59,5%59,5 % 60% 60% 66 % 66 % 76 % 76 % tial of the component 85% 85% 8.2016 assessment incorporates not only whether quality clinkers exists. For average contractor [3] Baunetz information, www.baunetzwissen.de/­ recycling is technically possible and actually labour costs of about €40 per hour, the price flachdach/fachwissen/flachdacharten/das-unbelueftete-flachdach-umkehrdach-155949, retrieved on practiced, but also what maximum proportion per brick would have to range from about 04.10.2017 the recycled product can represent in the €0.80 to €1.00, which is in line with the current [4]  see note 2 newly manufactured materials under technic­ purchase price of used solid bricks. An actual ally feasible circumstances – the Material Loop profit might be made with the dry-laid clinker Collaborators: Bildungszentrum des Baugewerbes e. V., BildungszenPotential (see p.63). facade system since the dismantling process trum des Deutschen Dachdeckerhandwerks e. V., BWM involves little effort, assuming that a market for Dübel und Montagetechnik GmbH, Daas Baksteen B. V., For example, it is currently possible to comsuch a system develops in the future. In the Derbigum Imperbel SA, Eternit GmbH, Foamglas GmbH, pletely recycle mineral-based composite insucase of reusable building materials with no Gutex GmbH & Co KG, Halfen GmbH, Kalzip GmbH, lating systems of aerated concrete, but if the market value (e.g. used fibre cement or slate MOLL bauökologische Produkte GmbH, Osmo Holz und Color GmbH & Co KG, Rathscheck Schiefer, Schüco amount of salvaged material were to exceed panels) or materials with a manufacturer take­International KG, Saint Gobain Isover G+H AG, Soprema the Material Loop Potential of the concurrent back system (e.g. recyclable bitumen sheetGmbH, Stebah GmbH, Thermo Natur GmbH & Co KG, total industrial production, the excess would ing), waste disposal expenditure does not vm Building Solutions Deutschland GmbH, Xella have to be disposed of. apply, although recovery revenues cannot be Deutschland GmbH, Ziegelei Hebrok Participants in the Master’s study course on “Sustainable The methodology used to assess loop potenexpected either since the necessary logistical Architecture Performance 2015/16” (Nachhaltige Archi­ effort ­usually cancels out the monetary value of tial under consideration of the economic tektur­perfomance 2015/16) at the Bergische Universität the recovered materials. ­viability of selective dismantling is described in Wuppertal, Chair of Building Construction, Design, MateriIn the present comparison, the post-and-beam the chapter “Assessment of Loop Potential” al Studies: Till Arlinghaus, Dario Gräfe, Deborah Hahn, facade and the zinc roof represent the most (p. 114ff.). Georg Haizmann, Nils Nengel, Fan Ling, Xenia Sagrebin

113

Assessment of Loop Potential Anja Rosen

The Utilitarian Benefit of Recycling “The rightness of human action is measured in its consequences. A measure for judging those consequences is their benefit (utility). But what matters is not only the benefit to the person performing the action. The critical factor is the well-being of all those impacted by the action.” [1] Based on this definition of utilitarianism, the overarching question for each recycling process becomes: Which goals does it achieve? To find an answer, other questions must first be resolved: What is the quality of the recycled substance and how can it be used? What effort is required in the dismantling and recycling processes, and is it worthwhile especially with regard to ecological and economic consider­ ations? In other words, is the recycling process sustainable? It is not about recycling as an end in itself and, by the same token, building

materials that are recyclable should not be assumed to be sustainable per se. The primary goal of recycling is the conservation of resources. The main focus lies on the biotic and non-biotic raw substances that are used to manufacture building products and materials. But the energy consumed throughout the life cycles of products, and also the land surface appropriated for the production of renewable resources – all of which are in constant competition with other uses (living space, food production, etc.) for that space – must also be considered. The nexus of recycling – energy – emissions

Apart from the conservation of resources, there are other goals of extreme ecological, societal and economic relevance that are closely associated with the utilisation of material and energy supplies, the most important of which is the minimisation of greenhouse gases and air pollutants. In the best-case scenarios, recycling

Building Assessment Data Additional information beyond the building’s life cycle

Information about the life cycle of the building

Scenarios

B 5.1 Life cycle assessment Modules A – D based on DIN EN 15 978 B 5.2 Loop potential of an aluminium post-and-beam ­facade with insulation glazing B 5.3 Materials used in an exterior wall example case (fractions by mass in %)

114

Scenarios

Removal C4

Potential for reuse, recovery and recycling

Scenarios

B6  Energy consumption during use

Scenario

B7  Water consumption during use

Scenario

Life Cycle System Limits

C3

Disposal

D Benefits and liabilities outside of the system’s limits

Waste processing

C1– C4

C1 C2 Dismantling / Demolition

Renovation

Replacement

B1 B2 B3 B4 B5

Repair

A5

Maintenance

A4

Use

Use

Production

Transportation

Sourcing of raw materials

A1 A2 A3

Construction

Construction / Installation

Manufacture

B1– B7

Transportation

A4 – A5

Transportation

A1– A3

B 5.1

Assessment of Loop Potential

A1 Timber A1 Timber

57.657.6 % % Pre-use Pre-use

Loam plaster Loam plaster FlaxFlax meshes meshes

23.023.0 % %

Post-use Post-use

2 [kg/m ] 2] [kg/m

Soil/loam Soil/loam

5.9 % 5.9 %

19.119.1 % %

Loam structural panels Loam structural panels

5.4 5.4 0.1 0.1 17.517.5

Squared timber facing installation 2.4 2.4 Squared timber facing installation

21.421.4% % 35.535.5 % %

0.1% 0.1% 14.414.4 % %

Material Loop Potential 114.5% Material Loop Potential 114.5% Pre-use Pre-use Recycled materials Recycled materials

21.121.1

Structural timber support frame Structural timber support frame 8.8 8.8

15.315.3 % %

2.6 % 2.6 % 10.010.0 % % 9.6 % 9.6 % Biological Biological A2 Timber A2 Timber pulppulp

Post-use Post-use Recycable materials Recycable materials Recoverable materials (downcycling) Recoverable materials (downcycling)

Fibreboard panels Fibreboard panels Cellulose cavity insulation Cellulose cavity insulation

14.014.0

Squared timber subconstruction Squared timber subconstruction9.2 9.2 Larch shingles Larch shingles

13.213.2 91.791.7

B 5.2

can contribute to both resource efficiency and emissions reductions. It all depends on the impacts of the recycling process. A proven tool for the analysis of resource consumption and environmental effects throughout the entire lifetime is the ecological life cycle assessment laid out in DIN EN 15 804 for building products and DIN EN 15 978 for buildings. According to both standards, the benefits and drawbacks of recycling lie outside of the life cycle and are essentially exported via Module D into the following life cycle (Fig. B 5.1). The starting point for quantifying Module D entries is: what is being substituted by the recycled product? The step does not assume that a product will be recycled per se, but also takes into account downcycling – both material and ­energetic – and feeds them into its statement of environmental impacts (see “Avoiding waste and recycling”, p. 59f.). The hardest problem in this process is esti­ mating the substitution options over relatively long time spans. At present, for example, waste wood can be used to replace fossil fuels. Because of the planned future conversion to 100 % renewable energy generation, however, when it is time to selectively demolish today’s new buildings, there will no longer be fossil fuels to replace. Nevertheless, Module D still calculates the savings in fossil fuel energy and the associated reduction in emissions for timber that is used in modern construction. On the other hand, the advantages of multi-step cascade utilisation in the long-term seques­ tration of carbon, for example, are not represented in the life cycle assessment. Another aspect that has thus far been neglected in life cycle assessments has to do with end-of-life decisions at the building level. The balance sheet makes use of purely statistical recovery rates, but disregards the buildingspecific installation situation and the separabil­ ity by type of the building products entirely. The life cycle assessment can only furnish a limited view of the recycling potential of built structures. Generally, it follows the principle of ecological efficiency and thus aims to minimise negative impacts on the environment. Because of the abundance of environmental indicators, the life cycle assessment tool is very complex

B 5.3

and is mostly only used in the context of certifications for business-to-business transactions. In practice, there exists a need for simple illustration methods that make positive effects easy to recognise. In such a method, the proportion of materials that can be kept in circulation in essentially closed loops could serve as a de­ cisive parameter. In ongoing doctoral dissertation work at the Bergische Universität Wuppertal, a method­ ology is currently being developed in which the loop potential described in the following paragraphs can be calculated and assessed [2]. Loop Potential of Constructions and ­Building Components Loop potential is determined at the buildingcomponent level and illustrated in two circular diagrams – the “loops” (Fig. B 5.2). The first loop clarifies the degree to which cycles are closed through the utilisation of recycled ma­ terials or renewable resources in the construction phase, that is, pre-use. The way in which these resources are included is immaterial; what matters is the fraction of renewable and secondary-use materials in the building products and thus in the building itself (Material Recycling Content – MRC; see “Recycling potential and reuse: Material Cycle Status”, p. 64). The second loop contains information about the degree to which cycles are predicted to close at the end of the utilisation phase (post-use). The determination of the post-use fraction takes into account the manner of construction, that is, the economic viability of selective dismantling. To do this, the materials expected to be recovered are listed and correl­ated with the recycling effort required and with their monetary value. Finally, a distinction is drawn between closed-loop potential and loop potential according to the definitions that follow. Definitions The loop potential of a construction predicts the fraction of building materials that can be reintroduced into a more-or-less closed

material loop in the post-use phase, taking into account their value and the detachability of their joining. Closed-loop potential

The closed-loop potential of a construction is the percentage of building materials and substances that can remain in use in a closed loop without loss in quality according to predefined criteria. Loop potential

In addition to the closed-loop fraction, the loop potential of a construction also includes the proportion of building materials and substances that can either be recovered with loss of quality (downcycling) or used for energy generation according to predefined criteria. Assessment Parameters and Calculation Methods The following parameters are used in the assessment of the loop potential of built structures or building components. Material Recycling Content – pre-use

Resource-conserving constructions should maximise their renewable or secondary ­material content while keeping non-renewable primary raw materials to a minimum. The pre-use loop potential therefore accounts for the fractions of both recycled materials (Material Recycling Content – MRC) and regrown raw materials (which are already naturally recycled). Resources and end-of-life scenarios – post-use

The resources expected from building demolition are determined from quantity surveys (see example in Fig. B 5.3). Those resource fractions that are anticipated in future to exceed the current standard of the German Commercial Waste Ordinance and to contain no landfill wastes can be assigned to the end-of-life scenarios shown in Fig. B 5.4, (p. 116) according to the demolition method and the associated purity of material separation. The post-use closed-loop potential includes the percentages of both reusable and recyclable materials. 115

Material

End-of-life scenarios Recycling Downcycling Energy recovery renewable fossil

Reuse

Concrete Brick

‡

‡

¥

‡

¥

Tiles and ceramic

‡ High-value end-of-life scenario: limited to used buil-

ding materials for which an established market exists or is anticipated (e.g. high-grade clinkers, large natural stones, oak beams), dismantling necessary ‡ High-value end-of-life scenario, selective dismantling necessary ¥ Usual end-of-life scenario (see MEoL, Fig. B 2.4, p. 64), selective dismantling

‡¥

Natural stone

‡

‡¥

Loam materials

‡

A1 and A2 Timber by Waste Wood Ordinance

¥

‡

‡

Biological pulp (compost)

‡

Glass

‡

¥ ¥

¥

Plastics

‡

Bitumen composites

¥

‡

Scrap, sorted by metal

‡

¥

‡¥

Manufacturer/ federation take-back (e.g. mineral wool, gypsum materials)

‡

B 5.4

the factors described in the following section (see also example in Fig. B 5.8).

The renewable resource timber represents a special case in this regard. As a rule, waste wood designated by the Waste Wood Ordinance as category A1 or A2 is either used in the manufacture of particleboard (considered downcycling) or in energy generation. Although a return to the biological cycle by way of decomposition is theoretically possible, it is does not actually occur in practice. The loop can still be closed, however, if the timber is taken from certified, sustainably managed sources, which guarantees that it will be replaced by new growth and that the forest will be preserved. Downcycling and energetic reclamation of timber are therefore considered part of the construction’s closed-loop potential as long as the timber is certified as sustainably sourced. Fig. B 5.6 gives an example of the closed-loop potential of a timber exterior wall. The identified materials are assigned to the various end-of-life scenarios on the basis of

Economic considerations

The economic viability of selective dismantling determines the probability with which resources are categorised into their highest available end-of-life scenarios. As the chapter “Can Loop Potential Be Measured?” (p. 108ff.) explains, the economic viability depends chiefly on the difficulty of recovery and the value of the recovered materials. The less work the selective dismantling takes and the more the materials are worth, the more profitable selective dismantling is and the greater the recycling probability (and the loop potential) become. The work factor

The disassembly or demolition effort is measured by the physical quantity “work”. Based on scientific investigations of dismantling pro-

Steel, scrap metal Stainless steel Copper Aluminium

€ 441 € 4,091 € 737

Zinc

[€/t, gross]

€ 1,600 € 153 € 188 0

€ -103 € -71 € -74 € -40 € -46 € -127 € -211 € -148 -200

-150

-100

-50

2,000

3,000

4,000 5,000

Clean mineral construction waste Slightly contaminated mineral construction waste Heavily contaminated mineral construction waste Concrete, unreinforced Concrete, reinforced Plaster and plasterboard Aerated concrete Glass A1 timber A2 timber Plastic for thermal reclamation Roofing felt containing bitumen or tar Mixed construction waste for waste disposal

€ -23 € -36 € -48 € -13 € -16

-250

1,000

0

The value factor

The economic value of the recoverable materials is determined on the basis of the current monetary market value in euros. The market value here refers to that of the materials delivered by the demolition contractor to the recycling/waste facility. Figure B 5.5 shows the average recycling revenues and costs of various types of waste in Germany as of 2016 [4].

The Material Loop Potential factor

[€/t, gross]

B 5.5

116

cesses described in the chapter “Can Loop Potential Be Measured?” (p. 108ff.), as well as on research done on demolition sites and on interviews with demolition contractors, the work factor fw is classified on a five-point scale ranging from minimal to very high (minimal, low, medium, high, very high) [3]. The demolition effort is recorded at the level of individual building layers (e.g. insulation, cladding) which are to be separated cleanly by type into the material fractions listed in Fig. B 5.4.

It must be noted that, at present, wastes belonging to the category “biological pulp” (compost) are as yet rarely accepted by the recovery facilities that process construction waste. If the resource transition [5] advocated by the Öko-Institut (Institute for Applied Ecology) – an event which would mark the transition from a predominantly linear to a circular economy – is implemented, the fraction of compostable biological pulp could increase. The price for pulp, which is currently similar to that of A2 timber, would then likely drop in response to the greater throughput. The value factor fV is determined by a sevenpoint scale ranging from very highly positive to extremely negative (very highly positive, highly positive, somewhat positive, somewhat negative, highly negative, very highly negative, extremely negative) [6].

€ 49

Water-struck clinkers, used, 2 kg/dm3 Natural stone slabs, limestone, used, 2 kg/dm3

Reuse: reusable materials Recycling: materials contain reusable substances Downcycling: materials contain recoverable substances Energy recovery: materials can be used for energy generation - renewable: derived from renewable sources - fossil: derived from fossil-based sources

When creating closed loops, it is critical to ascertain what the maximum technically achievable recycled material fraction of a new product could be (Material Loop Potential). For

Greenhouse potential [kg CO2-equiv/m2]

Assessment of Loop Potential

22.5 % 22.0 %

Pre-use

Post-use 28.8 %

59.3 %

Closed-Loop Potential 146.6 % Pre-use Recycled materials Regrown raw materials Post-use Recyclable materials Recoverable materials (downcycling) from certified renewable sources Energetically recoverable materials (energy recovery) from certified renewable sources

40 20 0

+ -

-20 -40 -60 -80 -100

B 5.4 B 5.5

B 5.6

many building materials the relevant substance- and product-specific properties are determined in “Examples of Materials: Fundamentals and Evaluation” (p. 63ff.). The Material Loop Potential enters into the loop potential calculations for a construction as a material-specific quantity. In the calculation, each material is multiplied by its characteristic Material Loop Potential factor. Prospects The quantitatively determined loop potential is useful for the objective assessment of constructions and for the presentation of positive effects. However, they can also be applied in wider-ranging life cycle assessments. The proportional end-of-life scenarios for Modules C and D in a building’s ecological balance sheet (Fig. B 5.1, p. 114) become calculable

Project / Building Material

Reusability: ease of disassembly

EoL scenarios

Reuse

B 5.8

B 5.7

Isolated life cycle data for various end-of-life scenarios already exist at building product level, e.g. for the material and energetic recycling of plastics. Under the sponsorship of the German Federal Environmental Agency, a research team is currently working on developing methodical foundations and

Reusability: Market exists Concrete recycling

Material Loop Potential (MLP) 0.39

B 5.7

with the potential assessment methods illustrated here. In addition, the building-specific installation situation mentioned at the outset is also taken into account in this approach. Figure B 5.8 demonstrates the described assessment methodology using concrete as an example, and indicates how these results could be adopted in a life cycle assessment. In the methodology, the evaluation parameters named above are ordered in terms of their project-specific and socio-economic impacts. The results of these evaluations could be used in a life cycle assessment.

Destructive demolition, no market exists

Work factor fW 0.9

B 5.6

Manu- Replace- Disposal Benefits and facture ment (C 3 − 4) liabilities (A1−3)* (B 4) outside the system’s *excludes loam structural panels limits (D) and flax due to insufficient data

Recovery paths

54 kg

46 kg

Recycling requirement met

Downcycling requirement met

19.5 kg

80.5 kg

Recycling

Downcycling

Recycled concrete

Civil engineering

Value factor fV 0.6 Recyclability requirements

Thermal recovery of renewable resources

Thermal recovery of fossil-based resources

Disposal

Society / Economy

14.0 %

100 80 60

Life Cycle Assessment Module C Life Cycle Assessment Module D

B 5.8

Resources and their end-of-life scenarios, used to determine loop potential Construction and demolition wastes: recovery proceeds and disposal costs (see note 4) Closed-loop potential of the exterior wall construction described in Fig. B 5.3 Greenhouse potential of the exterior wall construction described in Fig. B 5.3 Assessment methodology with transfer of results into the life cycle assessment, using concrete as an example

scenarios in order to make the product-specific information in Modules C and D available in an Environmental Product Declaration (EPD) [7]. The calculation of loop potential closes a gap in the utilisation of these types of product-related data and scenarios at building level. -

In the “Detailed Catalogue” -(p. 135ff.), the loop potential of selected constructions are given. The Global Warming Potential (GWP) is also presented as the most important indicator of the life cycle assessment (see also Fig. B 5.7). Since as yet there are hardly any Environmental Product Declarations with different end-of-life scenarios available, the greenhouse potential for the building components were extracted from generic or productspecific data given in the ecological database Ökobau.dat [8] and from EPDs based on statistical recovery rates.

Notes: [1] www.wirtschaftslexikon24.com/d/utilitarismus/utilitarismus.htm. Retrieved on 23.03.2018 [2] Rosen, Anja: Entwicklung einer Systematik zur quantitativen Bewertung des Kreislaufpotenzials von Baukonstruktionen in der Neubauplanung. Bergische Universität Wuppertal (dissertation in progress) [3] Benchmarks for the classification of the work and value factors will be published in Anja Rosen’s dissertation. [4] Personally conducted research done at 28 waste and recycling facilities throughout Germany. As of 08/2016 [5] Öko-Institut e.V.: Rohstoffwende 2049: Zur Zukunft der nationalen und internationalen Rohstoffpolitik. Documentation of 2016 Annual Meeting. www.oeko. de/forschung-beratung/themen/nachhaltige-ressourcenwirtschaft/rohstoffwende-2049-zur-zukunft-dernationalen-und-internationalen-rohstoffpolitik/. Retrieved on 28.05.2018 [6] see note 3 [7] Ingenieurbüro Trinius, Eva Schmincke and Institut Bauen und Umwelt e. V., Ressourcenschonende Gebäude – EPD für Bauprodukte: Demontage- und Recyclinginformationen (Module C und D) einschließlich gefährlicher Stoffe [8] Ökobau.dat: Online platform of the German Federal Ministry of the Interior, Building and Community for the publication of a standardised database for use in life cycle assessments of buildings. www.oekobaudat.de. Retrieved on 25.02.2018

117

Challenges in the Structural Design of ­Dismantling- and Recycling-Friendly ­Constructions Michael Wengert, Tobias Edelmann

The sustainability certification of a building requires processes that are separate from and supplemental to the building’s basic construc­ tion and operation procedures. The examin­ ation of these processes, i.e. the balancing of the so-called “grey energy” of the utilised materials, is closely related to the examination of the energy cycles in thermal building phys­ ics. In our view, therefore, in future it should logically be integrated in the energy verifica­ tion processes of the building code. From the perspective of building physics, the require­ ment for recycling-friendly construction is thus obvious, but it represents challenges, especially in structural design. What are the features that merit special consideration during the design and execution stages, which can be derived from these general principles? What is the technological state of the art, what develop­ ments can be anticipated, and where are the limits? Since recyclability is predicated on joining with detachable connections as well as on the material recoverability of individual compo­ nents, it leads to the immediate elimination of various options. This has to occur prior to the actual planning stage so that suitable ­alternatives can be found. In timber and steel construction in particular, the detachability of materials is a given, so that the use of these substances is especially suited for recycling-friendly construction and is a mainstay in many of the structures illustrated in the “Detailed Catalogue” (p. 135ff.). Timber is a renewable resource. In general, dry con­ struction timber does not have to be treated with wood preservatives which would restrict its recyclability. Metal materials are by nature predestined for reuse. As a rule, framed struc­ tures comprise a much more complex layering in their construction than their solid counter­ parts, and therefore require the appropriate individualised structural planning. Above all, the detachability requirement pre­ cludes the full-surface gluing of, for example, insulating materials (e.g. a facade with com­ posite thermal insulation, bituminous ­coatings of foam glass). In these cases, a constructive 118

solution must be sought. Possible approaches include factory-jointed slab ­systems (exterior walls, roofs, elevated floor plates), ballasting, detachable joints (including, in addition to point fasteners, e.g. hook-and-loop fasteners) and the use of recyclable bonding agents in timber construction. Potential defects may arise from thermal bridging in framework structures and metal joints as well as from the penetration of water- or vapour-proof surfaces. One a priori alternative to common wall con­ structions is a vapour-permeable structure. The advantage of vapour-permeable construc­ tions is that they transfer moisture intrusions outward thanks to their superior drying charac­ teristics, making them much more tolerant with regard to faults in execution than vapourproof constructions. Vapour-proof construc­ tions, by contrast, are more damage-prone and must therefore be designed and built with great care to ensure that they are absolutely leakfree. This is especially challenging since there are frequently no alternatives to the penetration of the sealing level without the use of adhe­ sives. The issue becomes especially relevant when materials such as loam structural ­panels and fibre insulation are used, since these ­readily absorb moisture. In each case, an air space placed on the outside of the insulation layer is the best approach to diverting moisture incursions. Departures from solid construction can lead to challenges in flat roof structures as well. When­ ever flat roof constructions are not rear-venti­ lated, they should be built so that there are no unmanageable cavities present on the cold side of the insulating layer, and so that the exterior sealing sheet is dark and free of shad­ ing and coverings, so it can dry after rainfall. The sealing sheeting always lies on the support structure as a homogeneous layer. In this case, in summertime the diffusion direction reverses toward the interior. Thus, a moisture-variable vapour barrier is placed on the inside. For fur­ ther information on this topic, see the contribu­ tor consensus reference document (Merkblatt zum Konsens der Referenten) to the “Ecological Timber Construction” conference of 2011 [1]. Other constructions, in which the insulating

Challenges in the Structural Design of ­Dismantling- and Recycling-Friendly ­Constructions

layer does not lie above the structural support, must undergo mandatory dynamic testing pro­ cedures with the appropriate software and can­ not be considered as universally acceptable options. Pitched roofs are subject to the same general construction principles, though they are always less susceptible to moisture intru­ sions from rainwater. On the subject of acoustics, the constructions examined in this publication occupy categories in which there are no definitive noise protection requirements (single-family houses); nor do any applicable standardised procedures exist, since a large number of parameters needs to be considered. Because of the construction methods, the transitions of structure-, air- and impact-borne sound are fluid, and statements about acoustic properties cannot be made based on the mass per unit area alone. For the constructions illustrated in the “Detailed Catalogue” (p. 135ff.), the aspiration is not to run simulations of critical situations but instead to use theoretical knowledge to come up with structural solutions which must then be calcu­ lated and tested on an individual basis. In prac­ tice, cavity walls exhibit a significantly better sound reduction index than single-leaf con­ structions. The acoustic decoupling effect via the reduction of sound bridges becomes espe­ cially relevant through the use of detachable connections, specifically point supports and specially-developed joining techniques. For impact sound reduction there are likewise struc­ tural approaches: elevated floors induce less vibration, where the most suitable options are oscillation-damping elastic constructions (e.g. using trapezoidal sheet). Measures can also be taken to raise the mass (flexible option: fills). A larger obstacle than detachable joining, ­however, is the general availability of recyc­ lable materials and building products. Syn­ thetic substances and composite materials can be specifically designed to incorporate techni­ cal characteristics that are often not achievable in natural products, or can be achieved only through ad hoc treatments (most notably in the areas of vapour-proofing, weatherproof­ ing and rot protection and fire protection). In

practice, this logically leads to a decrease in demand, and to the concomitant fact that many products lack National Technical Approval – both of which are problematic for construction planners. Though in the meantime a certain number of carefully conceived recyclable products or complete systems have been developed – including structural panels, insulation and, increasingly, the typical “problem products” such as sheeting (vapour-proofing and vapour barriers, seals) and even entire sealing sys­ tems – they generally do not perform as well in construction-physical applications as e.g. ­bituminous or synthetic materials; thus, finding products for moisture protection still remains the greatest challenge. The intention to build in a manner that does justice both to recyc­ lability and to building physics runs afoul of the limits of feasibility when it comes to glues and adhesive strips, if not sooner. In the category of installation-ready systems, it must also be pointed out that they often lack general com­ patibility, since they are usually conceived as “add-ons” for standard constructions (e.g. innovative cellar wall sealing systems in the form of insulating brick masonry walls). How then, after eliminating all non-recyclable options, is one to come up with a plan for a construction that departs in this way from established standards and guidelines? In con­ trast to the typical approach, in which the func­ tional layers are first defined and the suitable products are then chosen, the approach here must be highly individualised and, not least, dependent on the experience of the designer. If the elucidated principles and the market are known, one must decide at the very outset on a construction method that works and for which the components are available. In the ideal case, the planning process can then proceed without having to navigate the detours engen­ dered by dealing with construction-physical problems as they crop up, i.e. without going through a solution-finding phase. In the other case it makes sense to start with a general overview of the market so as to assemble a “construction kit” of recyclable products and

joining techniques; this kit can then be used to develop intelligent solutions, from which vari­ ous general principles can in turn be derived and applied to recyclable construction. Such constructions built from example products have been compiled in collaboration with the Bergische Universität Wuppertal (“Detailed Catalogue”, p. 135ff.). Though the importance of recycling-friendly construction has long been known, this repre­ sents just a small first step. Products are avail­ able for many applications, but many are untested special constructions that as yet lack National Technical Approval. At present, it falls to the designer or building client to formulate the sustainability claims regarding dismantling and recycling potentials; likewise they bear all the responsibility and liability for any risks or damages that may result. During a time in which goals are being defined and measures are being implemented at the political level for climate protection and the energy transformation, a series of certification systems proves that the recycling sector is also the object of increased attention. Responsible lawmakers would do well to adopt the require­ ments for building products and construction processes contained in these certifications into the life cycle evaluation process sooner rather than later. Thus it is urgently necessary for products and construction methods to undergo comprehensive testing and, where appropriate, optimisation. This would allow them to be included in the relevant standards, which can then be applied in future as broadly applicable foundations for the design of recyc­ ling-friendly construction.

Note: [1] Borsch-Laaks, Robert: Merkblatt zum Konsens der Referenten des 2. Internationalen Holz[Bau]PhysikKongresses »Holzschutz und Bauphysik« am 10./11. 02.2011 in Leipzig zum Thema: Unbelüftete Flachdächer in Holzbauweise. Leipzig 2011 (Con­ tributor consensus reference document for the 2nd International Wood [construction] Physics Congress 2011 “Ecological Timber Construction”, on the topic of unventilated flat timber roofs)

119

Cost Comparisons of Conventional and Urban Mining Design Constructions Petra Riegler-Floors, Annette Hillebrandt

Are loop-compatible constructions inherently more expensive, as is generally assumed? In order to answer this question, the following ­discussion will study the entire lifetime of a ­construction, including its erection, necessary upkeep during the use phase, demolition and waste disposal. During a building cost analysis, all design ­participants typically focus exclusively on the construction phase. The use phase, if it is considered at all, is usually viewed only from the perspective of energy. Most of the time, the demolition costs are given no attention. However, since expenses are nevertheless incurred for upkeep as well as for demolition and waste disposal, the following analysis will take into account the expenditures for all life phases of the construction in the calculation of its total cost (Fig. B 7.1). As this chapter focuses on the physical structure, the operational costs of supply, cleaning and maintenance as well as running repairs will not be considered here – in contrast to the life cycle cost analyses in the assessment methodologies [1]. In an experimental set-up presented at the end of the chapter, three examples featuring conventional and recyc­ ling-compatible construction versions are ­compared with one another (p. 128ff.). Determination of Project Costs The costs for construction are taken as much as possible from the current Construction Cost Index (BKI – Baukostenindex) [2]. For the few newer or less well-known materials not listed there, costs were determined by combining the price of the material (manufacturer’s list price) with the labour costs for the installation of a comparable material from the BKI. Material and installation costs

Costs for materials and their installation form the basis of construction costs. Material costs Recyclable materials have a reputation for being generally more expensive than their commonly used, less loop-compatible coun­ 120

terparts. Figure B 7.2 shows a comparison between different insulating materials in terms of construction and demolition as well as waste disposal costs (see “Insulation”, p.86ff.). A ­significant price advantage can be seen in the case of blow-in cellulose insulation. All mat- or panel-based insulation materials are in approximately the same price range, with jute insulating mats (made from used coffee or cacao sacks), rather than a mineral oil-based insulation, representing the least expensive variant. The differences in material costs, however, carry less weight overall because of the relatively high labour costs. Installation costs Many detachable joining techniques were not developed in order to facilitate dismantling by material type, but rather to allow for faster and predominantly weather-insensitive instal­ lation, reflected in labour, construction site ­provision and pre-financing cost savings. The comparison of two different joining techniques in facing masonry (Fig. B 7.4) illustrates the advantage of detachable connections: The installation time and associated labour costs of a newly developed dry bricklaying system are about one third less than those of the traditional mortar bonding method (see “Mortarless system for brick curtain walling”, p. 50). At the end of its life cycle the dry-laid facing wall is just as easy to disassemble again, and the clinkers can be sold for reuse (see “Facing brick shell on a load-bearing exterior wall”, p. 108f.). In addition, the work required to remove old mortar adhesions from the bricks before reuse is completely avoided. Upkeep costs: life cycle of the construction and product life

The product lifetimes used in the following studies are mostly taken from the BKI [3], the table “Service Lifetimes of Building Components” of the Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR) [4] and (for green roofs) from a project report compiled by the Fraunhofer Institute for Building Physics [5]. For a few of the newer or less well-known materials not

Cost Comparisons of Conventional and Urban Mining Design Constructions

Conventional construction

Recycling-compatible construction

Dismantling and recycling

€

€

Erection

Erection

€

€ Demolition and waste disposal

Repairs

Repairs B 7.1 Dismantling and disposal costs Installation

Costs [€]

published in these tables the calculations are based on manufacturer service life claims or, where applicable, on manufacturer guarantees. The building life cycle is taken to be 50 years. This corresponds to the time period that the evaluation methodologies of the DGNB ­(German Sustainable Building Council) and the BNB (Assessment System for Sustainable Building) use as a basis for most usage profiles (see “An Overview of Rating ­Systems”, p. 24ff.).

120 100

77

Raw materials with limited availability

Renewable resources

80 60 14

40 38

40

20 43

14 49

Demolition costs: dismantling and waste disposal

No comprehensive data sets or statistics are currently available for demolition and waste removal costs. A demolition cost index similar to the BKI (which covers construction and refurbishment costs) does not exist, though it would be an important tool to have in future. The few demolition costs published in the BKI are too lacking in detail and make no distinctions between joining techniques. Most demolition contractors rely on estimates

12

49

43

14

39

20

Many building materials, however, have a shorter lifetime than 50 years, meaning that they must be replaced once or even several times during this period. If several material ­layers are non-detachably joined, the assumption is that the entire compound structure will have to be replaced as soon as the lifetime of the shortest-lasting component is reached. The building component layers are viewed from the outside inwards, toward the building core, where in all cases the support structure remains untouched. The above reasoning was not employed for materials that would normally not be replaced even after their life expectancy had ended, provided that they are well protected from deterioration (e.g. plastic sheeting in a floor construction). Inexpensively manufactured building materials often also have short service lifetimes. If the costs of repeated repairs or replacements based on the product’s life over the course of the building’s life cycle are added to the original cost, a lower-cost material can turn out to be more expensive overall than an ­initially more costly yet longer-lasting material (Fig. B 7.3).

14

14

14

36

12

27

15

0

Cellulose blow-in Cork ­insulation ­panels TCC 040 TCC 040

Reed Jute Hemp FibreRock PUR EPS ­panels mats mats boards wool ­panels ­panels WLG 035 TCC 030 TCC 035 TCC 040 TCC 040 TCC 040 TCC 055

Seagrass blow-in insulation TCC 045

TCC = thermal conductivity class Dismantling and disposal costs (see note 6) All material and installation costs taken from BKI Part 3 (see note 2) as well as from manufacturer claims

B 7.2

Stainless steel (curtain facade)

Stainless steel 59 (curtain facade)

Aluminium honeycomb core panels (curtain facade)

Aluminium honeycomb core panels 45 (curtain facade)

Wood shingles (curtain facade)

Wood shingles (curtain facade)

42

Clinker slips 37 (cemented onto composite insulating system)

Clinker slips (cemented onto composite insulating system) Synthetic resin plaster (composite insulating system)

33

Synthetic resin plaster (composite insulating system)

Fibre-reinforced resin composite panels 29 (curtain facade)

Fibre-reinforced resin composite panels (curtain facade) 0

10

20

30

40

50

60

70

0

1

Lifetime [years] B 7.3 B 7.1  Period under consideration for project costs B 7.2 Net costs of 160-mm-thick insulation materials for use on an exterior wall, including installation, dismantling and disposal. Insulation from renew­ Mortar0.95 h = € 41.80 able materials is also advantageous from an bonded ­economic standpoint. B 7.3 Lifetimes of exterior cladding materials in years according to BKI (see note 3): long-lasting mater­ 0.60 h = €costs 26.40 Dry-laid ials save replacement B 7.4 Installation time of brick facing wall (h/m2) in ­mortar-bonded curtain wall and dry-laid system variants (labour costs in0.4 €, rates 0 0.2 0.6from BKI, 0.8 see 1.0 note 2; installation times from BKI and2manufacinstallation [h/m and €] turer claims): detachable joining saves labour costs

** Grafik B 7.4 ** 0.95 h = € 41.80 0,95 h= 41,80 € 0.95 h = € 41.80 0,60 h= 26,40 € 0.60 h = € 26.40 0 0,2 0,4 0,6 0,8 1,0 0 0.2 0.4 0.6 0.8 0.60 Montagezeit h = € 26.40 [h/m2 und €] [h/m2 Mörtelverbindung Trockenstapelsystem

Mortarbonded

Dry-laid

0

0.2 0.4 0.6 0.8 1.0 ** Ende Grafik ** installation [h/m2 and €] B 7.4

121

Price index Price index

Natural stone, gravel, sand, concrete and kaolin

120

Timber, cut and planed

Plastic products Natural stone, gravel, sand, concrete and kaolin

Glass and glass products Timber, cut and planed

Ceramic construction products Plastic products

Ready-mix concrete Glass and glass products

Metal constructions Ceramic construction products

Trend line Ready-mix concrete

Metal constructions

Trend line

120

110 110

100 100

90 90

80 80 70 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

70

Costs [€] Costs [€]

B 7.5 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

1.60 1.40 1.60 1.20 1.40 1.00 1.20 0.80 1.00 0.60 0.80 0.40 0.60 0.20 0.40 0.00 0.20

€ 1,40 ea. ca. 73 €/m2 € 1,40 ea. ca. 73 €/m2 € 0.70 ea. 30 – 40 €/m2 € 0.70 ea. 30 – 40 €/m2

0.00 New Belgian-style hand-moulded brick

Recycled dismantled brick B 7.6

122

B 7.5 Manufacturer price indices of commercial ­products – construction materials, Germany, 2000 – 2016, reference year 2010 (see note 13) B 7.6  Comparison of brick prices (see note 12) B 7.7 Urban mining – returns instead of waste disposal costs: predicted realisation of profits through the storage of raw materials in buildings using copper as an example

based on their own experience to come up with pricing proposals and, for competitive ­reasons, these are not made public. For the ­calculations in the following example projects, therefore, there were no average values based on large data samples to fall back on (see p. 128ff.). Instead, individually proposed pricing from a single demolition and waste removal company was used for the specific constructions in the examples so as to ensure that their costs could be fairly compared [6]. No special site-specific costs were taken into account, since the projects were fictitious. The costs and profit of dismantling At present, most of the materials resulting from a building demolition generate costs by virtue of the labour involved (wages, operation of machinery) and the charges incurred for their disposal. A once prominent example was the disposal of polystyrene (PS) containing hexa­ bromocyclododecane (HBCD), a toxic, per­ sistent and bio-accumulating flame retardant [7]: classified as hazardous waste, for a period of time its disposal required a special waste permit, as described on p. 86 in the section “Insulation” [8]. As a result, the disposal costs skyrocketed, increasing from about €120/t to approximately €450/t [9], and occasionally up to €1,000/t [10]. Conversely, it is also entirely possible to make a profit from dismantled materials. Common recycling paths exist, for example, for all types of scrap metal. Especially for aluminium and copper, the scrap metal price is only slightly less than that for new metal: high-quality scrap copper is valued at 95 % of the new copper price [11]. There are many other building materials or building components that can command a ­significant second-hand price, however. ­Examples include solid timber floorboards and door elements as well as solid bricks. ­During their use, solid mono-material building components are rarely damaged in a way that significantly impacts their value. In fact, they often acquire highly desirable signs of wear (patina) that make their reuse econom­ ically attractive. They retain their original value

Cost Comparisons of Conventional and Urban Mining Design Constructions

or at times even exceed it (Fig. B 7.6). Thanks to strong demand, for example, a recycled ­dismantled brick commands about twice the asking price of a similar-looking hand-moulded Belgian-style brick [12]. The bulk of the newly launched products on the market today are composite building materials, which offer the same visual appearance as valuable solid materials at a reduced installation price. However, at the end of their product lifetime (which is generally shorter), they have no resale value. In fact it is quite the opposite, as because of their composite bonding, their ­disposal is more difficult and usually quite expensive. Forecasts for raw material prices and disposal costs

Costs [€]

Predicting future trends is always a matter of speculation. Nevertheless, it is possible to estimate future developments in raw material and disposal costs in two ways: first, through past price trends, and second, by analysing the

existing reserves and sources of raw materials and the available remaining capacities of landfills, including those that are planned and authorised.

2000, they have risen by an average of 20 % [13]. It is likely that, at a minimum, raw goods prices will continue to rise at this rate. It will thus ­presumably be possible to sell material stored in a building at a higher price after ­demolition, as long as it can be selectively ­dismantled and is recyclable – i.e. the building becomes an urban mine.

Raw materials – post-demolition earnings Raw materials contained in buildings that can be recovered and separated by type generally have a resale value, which can generate welcome additional revenue if the prices of those materials have risen during the lifetime of the building.

Figure B 7.7 uses copper as an example to illustrate possible future pricing trends on the basis of data collected over the past 50 years. It clearly shows that using copper as a building material can yield a profit, in addition to the revenue generated by the use of the ­building itself (e.g. as rental property), its original purpose. An investment in the initially expensive material copper (e.g. in the facade) produces a second source of revenue after demolition, while an ­initially inexpensive ­material such as plaster merely generates ­disposal costs.

Price trends to date Prices for raw materials used in construction are influenced by various events (e.g. raw materials prices fell during the 2008 financial crisis and rose during the European debt crisis of 2010; timber prices fell due to over­ supply after Cyclone Kyrill in 2007). Consequently the price trends are not linear, though they tend to rise overall (Fig. B 7.5). Since

16,000

Uncosted increase after depletion of reserves

Estimates

14,000

12,000 per

Up

10,000

8,000

6,000

5,490

Copper price as of 13.09.2017

4,000

Est

5,200

e

ric dp

te

er

Scrap copper price Low as of 13.09.2017

)

r2

ppe

o of c

e of

ric dp

e

mat

Esti

X = uncosted inflation rate of scrap price after reserves are depleted

it

lim

fid

con

ima

6,851

e enc

p

scra

it

e lim

enc

fid con

)

r3

pe cop

Investment return of 1.27 + X % per year 1) 4) in addition to revenue from building use and in place of waste disposal costs Cycle B (50 years): 2017– 2067

Calculation of the material price only, not considering project-specific ­variations in installation and demolition costs 2)  Estimate of copper prices (see note 11) 3)  Estimate of scrap copper prices (see note 11) 4)  Determined with the aid of an online 2067 return-rate calculator 5)  see note 15 B 7.7 1) 

2,000

1,061 Historical copper price

1967

1,319

Investment return of 3.23% per year 1) 4) in addition to return on building use and in place of waste disposal costs Cycle A (50 years): 1967– 2017 2017 Date of study

2054 Predicted depletion of copper reserves 5)

123

Resources Chromium Indium

2477

2033 2154

2028

Cobalt

2274

2072

Copper

2054

Titanium Zinc

2166 2473

2154 2172

2030 2000

Reserves

2100

2200

2300

2400

2500

Predicted date of depletion [year] B 7.8

Reserves and Potential Resources All materials are present on the earth in specific quantities and are thus available on a ­limited basis. A distinction is drawn between reserves (material resources, which can be extracted with current technology in an ­economically ­viable manner) and potential resources ­(material resources, which exist but cannot currently be profitably extracted). Thanks to technological advances, available reserves are steadily increasing [14], but the potential resources are not. Figure B 7.8 shows the availability of a few selected metals and transition elements that are used either directly or as alloying elements in stainless steel [15]. However, metals are not the only substances that are becoming scarce – a few materials that were considered abundantly available are dwindling in dramatic fashion, e.g. river sand [16] that is used in the production of concrete, among other things (see “The Recycling potential of mineral materials”, p. 62). The following conclusion can be drawn from the developments described here: Because of the increasing scarcity of available raw materials, a disproportionate increase in the prices of many substances is to be expected in future. In addition, their value will be entirely lost after building demolition if they are not recyclable. The value of materials used to construct buildings that can be subsequently either reused or recycled is highly likely to increase. Disposal – post-demolition costs Materials that cannot be in some way either reused or recycled after demolition must be disposed of at considerable cost. Price trends to date As is the case for demolition costs, there are no available parameters based on large data samples that enable the cost of disposing of construction waste to be adequately estimated. Presumably, however, the prices ­illustrated in Fig. B 7.9 – compiled from the mutually complementary data sets of two demolition companies – represent general trends. In the period between the years 2000 and 2016, a significant rise in the waste dis124

posal costs for unseparated waste (over 100 % in the case of mixed construction waste) and for contaminated waste (over 1,000 % for contaminated wood) can be observed. But even purely mineral construction waste shows a cost increase of over 100 %, though in absolute terms it remains low. The cost of disposing of plaster and plasterboard within this time frame grew by a factor of eight. The comparatively strongly fluctuating disposal cost of timber (waste wood ­category II) is influenced by several factors: political interventions, such as the subsi­d­ising of wood-burning in Germany in the early 2010s as a means to generate electricity, which ­increased demand, and natural events such as storms, which produced a short-term ­oversupply of timber [17]. Limited landfill capacity In recent years, several German federal states, e.g. North Rhine-Westphalia [18], Bavaria [19] and Rhineland-Palatinate [20], developed ­predictions for landfill demand. These studies distinguish between various future scenarios: a linear extension of the ­status quo and an upper-­limit scenario reflec­ ting a change in the legal framework after the enactment of the Framework Ordinance (Mantelverordnung), the more stringent soil and water conservation requirements of which are likely to divert material streams toward landfills [21]. The North Rhine-Westphalian study also includes a more optimistic lower-limit scenario based on the increased acceptance of recyclable mineral building materials within an unchanged legal framework (Fig. B 7.10). All three forecasts reach the conclusion that the remaining capacity of the existing (including planned and authorised) landfills in the respective federal states will be exhausted before 2030. Public acceptance for the ­planning of additional new landfills is low. In addition, available land for this purpose is extremely limited due to Ger­many’s population density. As a rule, landfills have a primarily regional catchment area; delivery distances of more than 50 km are the exception. Shifting the waste problem to other countries is not a forward-looking ­solution, nor is

it cost-effective in all but isolated cases [22]. Based on the law of supply and demand, it must be assumed that waste deposits in landfills that have only very limited remaining space will become very expensive in future. A Comparison of Example Constructions On p. 128ff., three different building typologies are used as examples to compare conventional and recycling-compatible constructions. Experimental set-up

To ensure an adequate comparison of the three structures, calculations are based on the param­eters elucidated below. Experimental goals In each example, the two buildings under ­comparison, shown in the vertical facade section, exhibit (partly in reference to an existing building) the same function as well as the same proportions and are visually similar (e.g. dry-laid clinker curtain wall compared with bonded clinker slip facade). The construction, upkeep, demolition and waste disposal costs are determined for every item on the basis of the previously mentioned sources [23] and are then combined and grouped by building component for the sake of clarity. The calculations of building component costs are based on cost grouping (KG) 300 of DIN 276 [24]. Technical installations falling under KG 400, such as electrical units or special building components like stairs, are not considered. To determine upkeep costs, the usage cost groups 410 “Building repair” of DIN 18 960 “Usage costs in buildings” were used. In each case, the recycling-compatible version is illustrated in greater detail in the “Detailed Catalogue” (see p. 138ff., 158ff., 166ff.). Time frame All construction and demolition costs were ­calculated on the basis of data from the year 2017. The expected demolition and disposal costs for the year 2067 – at the end of the building’s useful lifetime of 50 years – were

Cost Comparisons of Conventional and Urban Mining Design Constructions

B 7.8  Reserves and potential resources of several ­metals and transition elements (see note 15): In the medium term, man-made repositories will have to be used. B 7.9  Disposal cost trends of selected construction and demolition wastes in €/t, 2000 – 2016 (see notes 9 and 10): general rise for all construction and demolition wastes, significant increases for mixed and contaminated wastes B 7.10 Class I landfill capacity and delivered waste quantities up to the year 2030 in North RhineWestphalia (Thörner / Harms, see note 18): Even the most optimistic scenario foresees the exhaustion of all landfill capacity by 2029. Mixed construction waste

estimated by assuming that past price trends would continue. Therefore, returns from the raw materials used to construct the building will be higher in 50 years, as will the cost of disposing of the construction waste.

Plaster, plasterboard Category II waste wood (suitable for material recycling)

Costs [€]

Category IV waste wood (suitable for energy generation only) 120 100 80 60 40 20 0 -20 2000

2005

2010

2016 B 7.9

Class I landfill capacity and delivery volumes [millions of m3]

Cash value method The costs of the example projects were dynamically calculated using the cash value method, taking into account the effects of inflation and discounting. Time is thus factored into the results both through inflation effects and through an expected return on investment. In other words, in the examples the time-adjusted ­monetary amounts are compared, i.e. the cash value that future transactions are calculated to have in the present. For building-related measures that lie in the future (upkeep, demolition and waste disposal), cost estimates incorporate expected price increases, whereupon these amounts are discounted to reflect their present values. Price increases and discounting have opposing effects: while price increases raise the cost, discounting (of unused, saved capital) results in cost reduction. The price inflation and discounting rates used have a significant effect on the results. The ­calculations done here are based on the values specified in the Assessment System for Sustainable Building (BNB). At present, the general rate of price inflation there is assumed to be 2 % per year, while the discount rate is 1.5 %. The data on which these rates are based come from an internal circular of the German Federal Ministry of Finance [25]. Other sources predict a larger interest rate for the 50-year projected time span; the Deutsche Bundesbank assumes 3.7 % [26], while the German Sustainable Building Council (DGNB) predicts 3.5 % [27]. In future, however, the higher-than-average price inflation rates mentioned earlier, precipitated by raw material and landfill scarcities, will have more marked impacts on the upkeep, demolition and waste disposal costs of buildings. Since these price increases are hard to quantify from the present perspective, the inflation rate used here for the sample calculations reflects the general inflation rate given by the BNB rather than specific inflation rates. To balance this choice, the BNB’s

Mineral construction waste (brick, concrete)

90

84.5

80 70 60 50 40 30 20 10 0

62.1 47.9 Remaining time including planned facilities 27,0 geplantes Volumen (2013ff.) Remaining time excluding planned facilities 29.0 Remaining capacity (2012)

Remaining capacity

51.3

2026

2029

2023

2018

2018

2018

Status quo scenario

Lower-limit scenario

Upper-limit scenario

Accumulated waste quantity 2012 – 2030 [1 m3 = 1.5 t] B 7.10

125

B 7.11 Present cash value cost comparison of floor ­coverings. Due to the cost of frequent replacement, the synthetic carpet, which ­appears ­initially to be the clearly more econom­ical choice, costs much more overall than the solid oak panel floor.

Costs [€]

lower discount rate was also used. Since the same source was chosen for both rates, the calculations remain internally consistent. In the following examples, the first calculations for each individual item are the manufacturing costs (price ≈ quantity), after which the upkeep or replacement costs for each item are determined. The upkeep costs comprise the construction costs for the replacement material, including installation, and the inflation rate up to the time of replacement (determined by the lifetime of the product). This amount is then ­discounted to yield the present value. If it is necessary to replace a building material several times during the building’s 50-year life span, the cash value is calculated for the date of each replacement. The same procedure is used for the removal/disassembly and disposal costs at the time of each replacement, as well as for the final demolition of the building at the end of the 50 years. In the examples, the individually calculated dismantling and disposal costs for replacements are combined 250

200

Total (cash value) € 218.51 2067 Demolition € 5.50

€ 35.00

-50

1)  2)  3) 

Total (cash value) € 110.61

2037 Replacement 2 € 117.00

€ 36.76 € 4.52

0

2047 Replacement 3

€ 38.61 € 4.74

50

2057 Replacement 4

€ 40.56 € 4.98

100

Replacement costs 1) Dismantling and disposal costs 2) Installation costs 1)

€ 42.60 € 5.23

150

with the amount reported for the final demolition. Figure B 7.11 illustrates the procedure using two versions of a building component (floor covering) as an example. The synthetic carpet, which at the outset looks to be a good deal at €35/m2, has a product life of 10 years and must therefore be replaced four times (with all the associated installation, removal and disposal costs). In the end it turns out to be substantially more expensive than the initially more costly solid oak panels, which cost €117/m2. The oak has a product life of more than 50 years, and at the end of the period under consideration it still commands a resale value even after the labour costs for selective dismantling are subtracted. Three factors determine which material is more economical in the final analysis: • the difference in the manufacturing costs of the materials to be compared • the replacement frequency, based on the given product lifetime • the individual dismantling and waste disposal costs

2017 Installation

2027 Replacement 1 2017 Installation

Synthetic textile floor covering (10 year product life) 3)

€ -6.39

Solid oak panel floor covering (> 50 year product life) 3)

Calculation of upkeep and installation costs from BKI Part 3 (see note 2) Dismantling and disposal costs given by demolition firm Kamrath (see note 6) Lifetime estimates from BNB (see note 4)

126

2067 Demolition (resale value after 50 years)

B 7.11

Building location The location posited for the example projects is Dortmund, as it lies at the approximate geographical centre of Germany and occupies an intermediate position in the German urbanrural spectrum. In determining the construction costs, the BKI’s regional factor of 0.879 for Dortmund is used. Dismantling and removal costs are based on calculations provided by the demolition firm assisting in this study [28]. All amounts listed represent the net costs for the completely installed or dismantled building materials. Conclusions: Is a building an urban mine or a disposal problem?

All three examples yield similar results: During the construction phase the loop-compatible buildings are initially more expensive, because recyclable and long-lasting materials are often more valuable per se, and because low sales volume tends to drive up the prices of these materials. In terms of renovation costs (including the removal and disposal of the old building ­components), constructions that can be dis­ assembled and recycled are advantageous. Thanks to detachable joining, individual layers can be renewed fairly easily without the need for replacing entire tightly bonded, layered constructions. In addition, recycling-friendly materials often last longer and have to be replaced less often. The upkeep costs in each of the three loop-compatible buildings are therefore significantly lower. In the demolition /dismantling phase, the costs of loop-compatible constructions are definitively lower than those of conventional buildings. While waste disposal for the latter incurs considerable further expenses, returns on investment can be had from raw materials incorporated in the former, and building ­materials can be economically reused or ­recycled. Owing to increasing densification in urban ­centres, almost every new building is ­preceded by the demolition of an existing one. In future, the value of a plot of land will not be measured just by present real estate

Cost Comparisons of Conventional and Urban Mining Design Constructions

standards such as its location, for ­example, but also by its associated buildings. Decisionmakers are faced with a choice: should these buildings be costly landfill additions or mines for raw materials? The long years of low-interest-rate policies on the part of central banks have led many invest­ ors to shift from the financial to the real estate market and to invest in so-called concrete gold – often in the form of an actual concrete building with a composite insulating system facade. Would it not make far more economic sense in the long term – assuming it was functionally feasible – to invest in a facade that incorporates raw materials with steadily increasing ­values such as copper and stainless steel and to choose a support structure of steel for the same strategic reasons? Or – depending on its structural suitability – to construct a timber building that will cost less to construct and dismantle, instead of investing in an expensive disposal problem? Legal provisions, such as a materials passport for buildings, or mandatory dismantling and recycling requirements recorded in the public easement register (see “Digital Data”, p. 14), could focus the attention of building ­clients on the entire life cycle of the building and on its associated costs. Until then, it is to be hoped that clever investors and clients will perform careful and comprehensive ­calculations ­covering all life cycle phases of their real estate investment before deciding on materials and construction methods, and that they will then opt for the least expensive and most ­forward-looking version: the loop-compatible building. Because of the limited availability of data on demolition and waste disposal costs, and owing to conservative estimates regarding future price inflation rates, the examination done here of the costs of buildings over their life cycles can only indicate a trend. It ­represents an experimental method that is intended to sensitise readers to the coming (presumably much more radical) developments in resource scarcity and disposal bottlenecks, and to offer them a new, comprehensive approach to addressing these issues.

Collaborators: Paul Kamrath, Paul Kamrath Ingenieurrückbau GmbH, Dortmund Guido Spars, Bergische Universität Wuppertal, Fach­ gebiet Ökonomie des Planens und Bauens (Division of the Economics of Design and Construction) Students at the Bergische Universität Wuppertal: Julia Blasius, Dorothee Kaspers, Fan Ling, Nils Schäfer Notes:   [1] Leitfaden Nachhaltiges Bauen. Published by the Federal Ministry of the Environment, Nature Conservation, Construction and Nuclear Safety (BMUB), 2016, p. 35 http://www.nachhaltigesbauen.de/fileadmin/pdf/ Leitfaden_2015/LFNB_D_final-barrierefrei.pdf   [2] BKI – Baukosten 2016 Neubau Teil 3: Statisti­ sche Kostenkennwerte für Positionen. Published by BKI Baukosteninformationszentrum. Stuttgart 2016   [3] BKI – Baukosten 2016 Neubau Teil 2: Statistische Kostenkennwerte für Elemente, Kapitel: Lebens­ dauern von Bauteilen und Bauelementen. Published by BKI – Baukosteninformationszentrum. Stuttgart 2016, p. 70 –106   [4] Nutzungsdauern von Bauteilen zur Lebenszyklus­ analyse nach BNB. Published by BBSR – Federal ­Institute for Research on Building, Urban Affairs and Spatial Development. Berlin 2017 http://www.nachhaltigesbauen.de/fileadmin/pdf/ baustoff_gebauededaten/BNB_Nutzungsdauern_ von_Bauteilen_2017-02-24.pdf. Retrieved on 29.03.2017   [5] Final report: Zuverlässige Beurteilung der hygro­ thermischen und energetischen Auswirkungen von Gründächern. Published by the Fraunhofer ­Institute of Building Physics IBP, Forschungsinitiative Zukunft Bau. Stuttgart 2013   [6] Paul Kamrath, Paul Kamrath Ingenieurrückbau GmbH, Dortmund  [7] Umweltbundesamt: Hexabromcyclododecan (HBCD) 2016; https://www.umweltbundesamt.de/ sites/default/files/medien/479/publikationen/faq_ hbcd_de_0.pdf, p. 4. Retrieved on 19.10.2017   [8] Decision of the Federal Council, 07.07.2017: https://www.bundesrat.de/DE/plenum/plenumkompakt/17/959/081.html?view=main[Drucken]& nn=5492626, retrieved on 20.09.2017   [9] see note 6 [10] according to Recyclingpark Harz GmbH, Gesell­ schaft für Recycling und Entsorgung, Nordharz, As of 10.02.2017 [11] Price of copper on 13.09.2017: €5,490.01/t https://www.boerse.de/historische-kurse/KupferEuro/XC0005705501?onlycontent=1; Copper scrap metal price Kabul (Milberry) on 13.09.2017: €5,200/t, market data. In: Recycling magazin, 18/2017, p. 37 [12] Backstein-Kontor, Köln-Ehrenfeld, offer on 03.05.2017

[13] Statistisches Bundesamt Wiesbaden (Eds.): ­Erzeugerpreisindizes gewerblicher Produkte ­(Inlandsabsatz) nach dem Güterverzeichnis für Produktionsstatistiken, 2009. www.genesis.destatis. de. Retrieved on 07.02.2017 [14] Umweltbundesamt, Fachgebiet III 2.2 (Eds.): Urban Mining – Ressourcenschonung im Anthropozän. Dessau-Roßlau 2017 https://www.umweltbundesamt.de/sites/default/ files/medien/1968/publikationen/uba_broschuere_ urbanmining_rz_screen_0.pdf [15] CUTEC-Studie: Prüfung und Aktualisierung von Rohstoffparametern. Published by Clausthaler ­Umwelt-Institut. Clausthal-Zellerfeld 2016 [16] https://www.ethz.ch/de/news-und-veranstaltungen/ eth-news/news/2014/10/sand-teil-1-eine-endlicheressource.html, retrieved on 01.02.2018 [17]  see note 6 [18] Prognos AG / Thörner, Thorsten; INFA GmbH / Hams, Sigrid: Bedarfsanalyse für DK I-Depo­ nien in Nord­rhein-Westfalen. Zusammenfassung der Ergebnisse. Study by order of the Ministry for Climate Protection, Environment, Agriculture, ­Nature and Consumer Protection of the State of North Rhine-Westphalia. Berlin / Düsseldorf /Ahlen 2013 [19] AU Consult GmbH: Bedarfsprognose: Deponien der Klassen 0, I und II in Bayern. Short version of the study by order of the Bavarian State Office for the Environment. Augsburg 2015 [20] u.e.c. Berlin; ifeu Heidelberg; Dehne, Iswing et al.: Abschätzung des zukünftigen Bedarfs an Deponie­kapazitäten in Rheinland-Pfalz. Short ­version of the study by order of the State Office for the Environment Rhineland-Palatinate. Berlin/Heidelberg June 2016 [21] http://www.bmub.bund.de/fileadmin/Daten_BMU/ Download_PDF/Gesetze/mantelv_vorblatt_begruen­ dung.pdf. Retrieved on 01.02.2018 [22] Thörner, Thorsten; Harms, Sigrid: Deponien braucht das Land. In: Recycling magazin, 09/2015, p. 12 –15 [23] see notes 1, 2, 4, 5, 6 as well as manufacturer ­pricing [24] DIN 276-1:2008-12 Construction costs – Part 1: Buildings [25] Bundesministerium für Umwelt, Naturschutz, Bau und Reaktorsicherheit (BMUB): BNB – Steckbrief Büro- und Verwaltungsgebäude 2015 https://www.bnb-nachhaltigesbauen.de/fileadmin/ steckbriefe/verwaltungsgebaeude/neubau/v_2015/ BNB_BN2015_211.pdf, p. 13 [26] Discount rates of the Deutsche Bundesbank: https://www.bundesbank.de/Navigation/DE/ Statistiken/Geld_und_Kapitalmaerkte/Zinssaetze_ und_Renditen/Abzinsungssaetze/Tabellen/tabellen. html, retrieved on 07.09.2017 [27] Deutsche Gesellschaft für Nachhaltiges Bauen (DGNB) e. V., valid based on system version 2017, information as of 14.11.2017 [28]  see note 6

127

Cost Comparison 1

Conventional Construction Solid lightweight concrete construction with clinker slip facade Roof

Gravel layer, vegetation, plant substrate (lavapumice mixture), PE / PP filter matting, EPS water drainage panels, PE / PP root barrier ­matting, separating sheet, polymer bitumen sealing membrane, EPS insulating panel, PP composite vapour-proofing, aerated concrete ceiling panels, plaster

Building type

School Storeys

2 + partial cellar GFA

1,885 m2 GBV

12,063 m3

Floors

Synthetic fibre blend carpet (glued), calcium sulphate screed with floor heating (plastic pipes), synthetic blend separating membrane, EPS impact sound insulation, aerated concrete ceiling panels, plaster

Pertinent Cost Factors + = positive impacts  - = negative impacts

Loggia

Steel terrace balustrade, concrete pavers, epoxy resin drainage mortar, polymer bitumen sealing membrane, graded EPS insulation, PA vapour-proofing (glued), aerated concrete ceiling panels, plaster

Conventional construction

 - Facade including windows and insulation and interior wall cladding must be replaced once  - Floor coverings must be replaced four times  - High disposal costs for plaster (which requires manual removal before demolition of the concrete underneath), aerated concrete, EPS

Exterior walls

1:500

a

a

Clinker slips in cement mortar with fibreglass reinforcement, EPS insulation, aerated concrete blocks, imitation wood PVC panels (glued) Windows

Plastic windows with triple glazing and sun ­protection coating, window sills: aluminium coated exterior, cast concrete interior, plaster jambs

1:500

Recycling-compatible construction

+ Long-lasting interior wall cladding + Finished interior facing of solid timber ­support structure (no additional covering necessary) + Clinkers and oak floorboards have a resale value

Interior walls

Aerated concrete blocks, imitation wood PVC panels (glued) Foundation /ground slab

Synthetic fibre blend carpet (glued), calcium sulphate screed with floor heating (PVC pipes), synthetic blend separating membrane, EPS insulation, reinforced concrete ground slab, bitumen membrane, lean concrete sub-base Cellar walls

Synthetic blend filter matting, synthetic blend dimpled membrane, XPS perimeter insulation, thick bitumen coating, aerated concrete, ­imitation wood PVC panels (glued)

aa

a

Replacement costs (present cash value)

Dismantling and disposal costs for repairs and for demolition after 50 years (present cash value)

Total costs

€ 127,146

€ 93,184

  € 57,310

€ 277,640

€ 120,609

€ 116,466

  € 71,289

€ 308,364

€ 73,398

€ 43,719

€ 17,428

€ 134,545

Exterior walls ­ including windows

€ 227,522

€ 215,448

€ 163,487

€ 606,457

Foundation including ­cellar walls

€ 181,738

€ 61,958

€ 141,346

€ 385,042

Total

€ 730,413

€ 530,775

€ 450,860

€ 1,712,048

Cost group

Conventional construction

KG 360

Roof

KG 350

Floors including loggia

KG 340

Interior walls

KG 330 KG 320

Construction costs

a

B 7.12

128

Cost Comparisons of Conventional and Urban Mining Design Constructions

Recycling-Compatible Construction Solid timber construction with clay brick drylaid facade (see “Detailed Catalogue” Ex. 07, p. 166ff.) Roof

Gravel layer, extensive green roof, sedum cover with jute underlayer, substratum of re­ cycled crushed brick, loosely laid with ballast, recycled PS drainage panels, PE-HD sealing sheet, tube insulating panels, loosely laid PE-LD vapour-proofing, stacked board ceiling, aluminium flat roof end profile Floors

Linoleum tiles with HDF support panels, wood fibre insulating panels, floor battens, recycled crushed ceramic fill, spruce stacked board ceiling

Roof ­insulation

Conventional EPS Cork

Floor ­covering

Mixed synthetic carpet Linoleum

Interior wall cladding

PVC Timber

Windows

Plastic Wood-aluminium

Exterior wall insulation

EPS tube

Exterior wall cladding

Clinker slips Dry-laid brick system 0

10

20

Cost by life cycle phase [€]

Oak terrace balustrade, timber planks (oak), graded timber planks, rubber granulate building protection matting, PE-HD sealing sheet, tube insulating panels, PE-LD vapour-proofing, OSSB structural panels, recycled crushed ceramic fill, graded timber planks, stacked board ceiling Exterior walls

Dry-laid facing bricks, OSSB structural panels, tube insulating panels, construction timber, solid timber wall of vertically jointed spruce slats

1,000,000

40 50 Lifetime [years]

Conventional

Recycling-compatible

800,000 600,000 400,000 200,000 0

Windows

Wood-aluminium window, triple glazing, ­window sills: aluminium exterior, solid wood interior, solid wood jambs

Construction Replace- Dismantling and costs ment costs disposal costs for (cash value) replacements and final demolition after 50 years (cash value) B 7.15

Interior walls

Total costs by construction type [€]

Timber frame wall with wood fibre insulation, OSSB structural panels, squared timbers, spruce cladding Foundation /ground slab

Pine timber planks, spruce floor battens, wood fibre insulation panels, stacked pine board floor, foam glass insulation panels, loosely laid waterproofing system (geosynthetic drainage composite with a PE-HD drainage core and PE-HD sealing membrane), sand sub-base Cellar walls

Loosely laid waterproofing system (geosynthetic drainage composite with a PE-HD drainage core and PE-HD sealing membrane), foam glass gravel in textile wall bags, solid timber wall of vertically jointed spruce slats Recycling-compatible construction

30

B 7.14

Loggia

Cost group

Recycling-compatible

Construction costs

Replacement costs (present cash value)

Dismantling and disposal costs for repairs and for demolition after 50 years (present cash value)

Erection

1,600,000 1,400,000 1,200,000 1,000,000 800,000 600,000 400,000 200,000 0

conventional construction

recycling-compatible construction B 7.16

Total costs

KG 360

Roof

€ 186,734

€ 77,460

€ 8,486

€ 272,680

KG 350

Floors including loggia

€ 192,763

€ 94,274

€ 29,896

€ 316,933

KG 340

Interior walls

€ 71,652

€0

€ 7039

€ 78,691

KG 330

Exterior walls ­ including windows

€ 208,527

€ 17,111

€ 58,052

€ 283,690

KG 320

Foundation including cellar walls

€ 285,285

€0

€ 56,543

€ 341,828

Total

€ 944,961

€ 188,845

€ 160,016

€ 1,293,822

,

1,800,000

Repairs (50-year life cycle) Dismantling and disposal

B 7.12 Table of costs for conventional construction by cost group B 7.13 Table of costs for recycling-compatible ­construction by cost group B 7.14 Lifetimes of several building materials taken from BKI-2 (see note 3) and BNB (see note 4) B 7.15  Comparison of costs by life cycle phase B 7.16 Comparison of total costs by construction type All quantities given represent net prices for fully installed or dismantled building materials. Section • Ground floor layout Scale 1:1,000 Vertical sections  Scale 1:50

B 7.13

129

Cost Comparison 2

Conventional Construction EPS formwork blocks with concrete cores and imitation wood HPL panel facade Roof

2 + upper level setback

PVC decking on PVC subconstruction, PVC waterproofing sheet, EPS insulation, PP composite vapour-proofing, reinforced ­concrete ceiling, plaster, aluminium parapet

GFA

Floors

145 m2

PVC vinyl floor covering (glued), fibre cement screed, synthetic blend separating membrane, EPS impact sound insulation, reinforced concrete ceiling, plaster, fibreglass wallpaper

Building type

Single-family house Storeys

GBV

1,100 m3

Exterior walls

HPL panels on substructure, EPS formwork blocks with in-situ concrete cores, plasterboard panels, fibreglass wallpaper

Pertinent Cost Factors + = positive impacts  - = negative impacts

Windows

Plastic window frames with triple glazing, PVC drip plate, PVC window sill

Conventional construction

 - Facade including windows and insulation and interior wall cladding must be replaced once  - High disposal costs for plaster, EPS ­formwork blocks with concrete cores, EPS, reinforced concrete, PVC materials, ­heterogeneous gravel materials

Interior walls

Plasterboard stud partition walls with fibreglass wallpaper Foundation /ground slab

PVC vinyl floor covering (glued), fibre ­cement screed, synthetic blend separating membrane, EPS impact sound insulation, ­bitumen waterproofing membrane, re­ inforced concrete ground slab, synthetic blend separating membrane, XPS perimeter insulation, lean concrete, heterogeneous gravel bed

Recycling-compatible construction

- Wood shingle facade cladding and insulation must be replaced once + End of life/disposal: low quantities and costs for timber framework + Returns for copper sheet, steel building components (terrace subconstruction)

aa

a a

a a

Construction costs

Replacement costs (present cash value)

Dismantling and disposal costs for repairs and for demolition after 50 years (present cash value)

Total costs

Roof

€ 38,974

€ 20,684

€ 62,193

€ 121,851

Floors including roof terrace

€ 19,153

€ 6288

€ 8,162

€ 33,603

KG 340

Interior walls

€ 12,482

€ 12,741

€ 5,625

€ 30,848

KG 330

Exterior walls and windows

€ 113,499

€ 100,346

€ 89,773

€ 303,618

KG 320

Foundation /ground slab

€ 30,005

€ 4193

€ 31,064

€ 65,262

€ 214,113

€ 144,252

€ 196,817

€ 555,182

Cost group

Conventional construction

KG 360 KG 350

Total

B 7.17

130

Cost Comparisons of Conventional and Urban Mining Design Constructions

Recycling-Compatible Construction Timber panel construction with larch and copper shingle facade (see “Detailed Catalogue” Ex. 04, p. 152ff.)

Conventional

Roof with roof terrace

Galvanised flat steel balustrade with steel cable, black locust timber decking, black locust floor battens, galvanised steel Å-beams, retractable steel legs, rubber granulate building protection matting, plant-based bitumenand halogen-free roof sealing membrane, wood fibre insulating panels, coarse-grained aluminium vapour-proofing foil, OSB structural panels (formaldehyde-free), glued laminated timber ceiling beams, panelling, loam structural panels with fine loam plaster, copper parapet

Interior wall cladding

Wallpaper Loam plaster

Windows

Plastic Timber (oak)

Exterior wall insulation

EPS Cellulose

Exterior wall cladding

HPL panels Wood shingles 0

10

Cost by life cycle phase [€]

Cork floor panels with HDF mounting plate, ­timber floor battens, wood fibre impact sound insulation panels, cork acoustic decoupling layer, diagonal solid timber panelling, glued laminated ceiling beams, sheep’s wool airborne sound insulation, facing panelling, loam structural panels with fine loam plaster Exterior walls

Larch wood shingles on battens / recycled-­ copper shingles on timber formwork, counter battens, MDF panels, counter battens, ­waste-paper cellulose fibre cavity insulation, fibreboard panels, solid KVH timber, wastepaper cellulose fibre cavity insulation, fibreboard panels, counter battens, facing panelling, loam structural panels with fine loam plaster and filling

300,000

Conventional

100,000

B 7.20

Total costs by construction type [€]

Erection

Timber frame wall with wood fibre insulation, loam structural panel with fine loam plaster Foundation /ground slab

Cork floor panels with HDF mounting plate, ­timber floor battens, wood fibre impact sound insulation panels, cork acoustic decoupling layer, diagonal solid timber panelling, glued laminated floor beams on galvanised steel angle bars, waste-paper cellulose fibre cavity insulation, timber formwork, galvanised steel ground screw footings

Construction costs

Replacement costs (present cash value)

Dismantling and disposal costs for repairs and for demolition after 50 years (present cash value)

Total costs

Roof

€ 44,679

€ 14,654

€ 1,843

€ 61,176

Floors including roof terrace

€ 25,366

€ 12,385

€ 3,713

€ 41,464

Interior walls

€ 26,511

€0

€ 4,392

€ 30,903

€ 137,762

€ 86,488

€ 29,678

€ 253,928

€ 27,797

€ 14,667

€ 2,371

€ 44,835

€ 262,115

€ 128,194

€ 41,997

€ 432,305

KG 340 KG 330

Exterior walls and windows

KG 320

Foundation /ground slab Total

Recycling-compatible

Construction Replace- Dismantling and costs ment costs disposal costs for (cash value) replacements and final demolition after 50 years (cash value)

Interior walls

KG 350

40 50 Lifetime [years]

0

Natural oak wood window frames, triple ­glazing, copper drip plate, solid wood sill

KG 360

30

200,000

Windows

Recycling-compatible construction

20

B 7.19

Floors

Cost group

Recycling-compatible

Interior wall Plasterboard construction Loam construction panels

Replacements (50-year life cycle) Dismantling and disposal

600,000 500,000 400,000 300,000 200,000 100,000 0

Conventional construction

Recycling-compatible construction B 7.21

B 7.17 Table of costs for conventional construction by cost group B 7.18 Table of costs for recycling-compatible ­construction by cost group B 7.19 Lifetimes of several building materials taken from BKI-2 (see note 3) and BNB (see note 4) B 7.20  Comparison of costs by life cycle phase B 7.21  Comparison of total costs by construction type All quantities given represent net prices for fully installed or dismantled building materials. Section • Ground floor layout Scale 1:1,000 Vertical sections  Scale 1:50

B 7.18

131

Cost Comparison 3

Conventional Construction Limestone masonry with fibre-reinforced resin composite panels Roof

Concrete roof tiles, battens, counter battens, synthetic composite underlay, OSB panels, ­rafters packed with EPS insulation, OSB ­panels, synthetic composite vapour-proofing membrane, reinforced concrete ring beam

Building type

Office building Storeys

2 + attic GFA

491 m2

Floors

Laminate (glued), concrete floor heating screed with plastic pipes on a radiant heating mounting system with surface-bonded EPS impact sound insulation, synthetic blend ­separating membrane, reinforced concrete slabs, plaster, fibreglass wallpaper with ­emulsion paint

GBV

1,842 m3

Pertinent Cost Factors + = positive impacts  - = negative impacts

Balcony

Tiles (glued), epoxy resin drainage mortar, ­synthetic blend drainage matting, polymer ­bitumen waterproofing membrane, graded cement screed, prefabricated reinforced ­concrete element with insulated rebar connectors, fibre-reinforced resin composite panels on aluminium substructure

Conventional construction

 - Manufacturing costs for solid reinforced ­concrete construction  - Facade including windows and insulation and interior wall cladding must be replaced once  - Floor coverings, wallpaper must be replaced several times  - High disposal costs for facade panels, ­plaster, EPS, concrete materials, slag ­support layer + End of life/disposal: aluminium subconstruction is cost-neutral (cost of dismantling approximately cancels out credit for material)

Exterior walls

Fibre-reinforced resin composite panels, ­aluminium substructure, polyester fleece ­windproofing, EPS insulation, limestone brick masonry, plaster, ingrain wallpaper with emulsion paint Windows and doors

PVC windows/doors with triple glazing, ­window sills (exterior sills, aluminium-coated) Interior walls

Limestone masonry, plaster, fibreglass wall­ paper with emulsion paint, wood composite door frames and leaves with plastic coating

Recycling-compatible construction

 - Replacement of inner layers of exterior wall cladding and insulation + Product life of interior wall cladding and ­construction, floor coverings, facade and windows + End of life /disposal: low mass and costs for timber materials, high return on copper heating pipes and facade and ­support ­structure

Foundation /ground slab

Laminate (glued), concrete floor heating screed with plastic pipes on a radiant heating mounting system with surface-bonded EPS impact sound insulation, PUR insulation, polymer-­modified bitumen thick-film coating with fabric inlay, reinforced concrete slab, lean concrete sub-base, synthetic blend ­separating membrane, slag support layer

Cost group

Conventional construction

Construction costs

Replacement costs (present cash value)

Dismantling and disposal costs for repairs and for demolition after 50 years (present cash value)

Total costs

KG 360

Roof

€ 41,169

€ 26,133

€ 17,871

€ 85,173

KG 350

Floors including balcony

€ 77,931

€ 52,756

€ 36,404

€ 167,091

KG 340

Interior walls

KG 330

Exterior walls including windows and entry door

KG 320

Foundation /ground slab Total

€ 31,228

€ 61,372

€ 10,932

€ 103,532

€ 162,962

€ 171,295

€ 92,698

€ 426,955

€ 50,353

€ 17,845

€ 41,113

€ 109,311

€ 363,643

€ 329,401

€ 199,018

€ 892,062 B 7.22

132

Cost Comparisons of Conventional and Urban Mining Design Constructions

Recycling-Compatible Construction Steel framework with stainless steel clip-on ­panels (see “Detailed Catalogue” Ex. 01, p. 138ff.) Roof

Stainless steel clip-on panel sheeting and subconstruction, galvanised trapezoidal sheeting, battens, PE-HD windproofing, MDF panels, jute fibre insulation panels, battens, HEB 200 steel profiles, solid KVH timber secondary construction, jute fibre cavity insulation, PE-LD vapourproofing sheeting, OSB/3 panels, metallic hookand-loop ­fastener, battens, jute fibre lining

Roof ­insulation

Conventional Polystyrene Hemp fibre

Floor ­covering

Laminate Mastic asphalt screed

Interior wall cladding

Wallpaper Loam plaster

Windows

Plastic Stainless steel

Exterior wall PUR Jute fibre insulation Exterior wall Resin-composite panels Stainless steel clip-on panels cladding

Floors

Mastic asphalt screed, copper heating pipes, recycled grey board separating layer, wood fibre insulating panels, sand fill, galvanised ­trapezoidal sheets, HEB 200 steel profiles, solid KVH timber secondary construction, counter battens, battens, metallic hook-and-loop fasteners, battens, jute fibre lining

0

20

30

40 50 Lifetime [years] B 7.24

Cost by life cycle phase [€]

Mastic asphalt screed, galvanised dovetail steel sheeting, recycled rubber granulate building ­protection matting, plant-based roof sealing membrane (bitumen- and halogen-free), OSB /3 panels, HEB 120 steel profiles, balustrade: ­galvanised HEB 120 steel profiles, stainless steel clip-on panels, aluminium subconstruction

Recycling-compatible

600,000

400,000

200,000

0

Construction Replace- Dismantling and costs ment costs disposal costs for (cash value) replacements and final demolition after 50 years (cash value)

Exterior walls

Stainless steel clip-on panels and subconstruction, PE-HD windproofing, MDF panels, jute fibre insulating panels, battens, cavity insulation, jute fibre insulating panels, U 200 steel profiles, solid KVH timber secondary construction, OSB/3 ­panels, PE-LD vapour-proofing, metallic hookand-loop fasteners, battens, jute fibre lining

B 7.25

Total costs by construction type [€]

Windows and doors

Glued laminated timber post-and-beam construction with stainless steel capping strip, terrace door: stainless steel frame, triple glazing Interior walls

Timber frame construction with jute fibre insulation panels, loam structural panel planking with fine loam plaster, doors: solid wood frames with solid core leaves, veneered Foundation /ground slab

Mastic asphalt screed, recycled grey board separating layer, PE-LD vapour-proofing, wood fibre insulation panels, sand fill, trapezoidal sheeting, galvanised HEB 200 steel profiles, ­galvanised steel ground screw footings

1,000,000

Erection

Repairs (50-year life cycle) Dismantling and disposal

900,000 800,000 700,000 600,000 500,000 400,000 300,000 200,000 100,000 0

Conventional construction

Recycling-compatible construction B 7.26

Replacement costs (present cash value)

Dismantling and ­disposal costs for repairs and for ­demolition after 50 years (present cash value)

Total costs

Cost group

Recycling-compatible construction

KG 360

Roof

€ 104,427

€ 30,770

€ 83

€ 135,114

KG 350

Floors including balcony

€ 78,127

€ 7,729

€ 187

€ 85,669

KG 340

Interior walls

€ 38,203

€0

€ 12,036

€ 50,239

KG 330

Exterior walls including ­windows and entry door

€ 232,078

€ 59,680

€ 2,402

€ 294,160

KG 320

Foundation /ground slab

€ 33,582

€0

€ 10,683

€ 44,265

€ 486,416

€ 98,179

€ 24,851

€ 609,447

Total

10

Conventional

Balcony

Construction costs

Recycling-compatible

B 7.22 Table of costs for conventional construction by cost group B 7.23 Table of costs for recycling-compatible ­construction by cost group B 7.24 Lifetimes of several building materials taken from BKI-2 (see note 3) and BNB (see note 4) B 7.25 Comparison of costs by life cycle phase B 7.26 Comparison of total costs by construction type All quantities given represent net prices for fully installed or dismantled building materials. Section • Layouts of ground floor and first floor Scale 1:1,000 Vertical sections  Scale 1:50

B 7.23

133

134

Part C  Detailed Catalogue

Steel Construction 01 Steel Skeleton Construction / Stainless Steel Clip-On Panel Facade Determination of Loop Potential 02  Steel Skeleton Construction / Glass Ceramics Panel Facade 03  Steel Skeleton Construction / Natural Stone Panel Facade Timber Construction 04 Timber Panel Construction / Larch and Copper Shingle Facade Determination of Loop Potential 05  Timber Panel Construction /Aluminium Honeycomb Composite Panel Facade 06  Timber Panel Construction / Charred Timber Formwork Facade 07 Solid Timber Construction / Dry-laid Clay Brick Facade Determination of Loop Potential Bathrooms 08 Metal Bathroom: Steel Skeleton Construction / Weather-Resistant Structural Steel Panel Facade 09  Glass Bathroom: Steel Skeleton Construction / Channel Glass Facade

138 144 148 152 158 162 166

172 175

The Rauch House, Schlins (AT) 2008, Boltshauer Architekten with Martin Rauch

135

The best possible potential (given currently available recycling paths) for the continued use of all materials used in the following constructions is indicated as end-of-life potential using these criteria: Wiederverwendung Wiederverwendung

Verfüllung/„Landfill“ Wiederverwertung Deponie Kl. 0

Reuse

Recycling

If a product can be used again for its ori­ Wiederverwertung ginal purpose, it is assigned to the “Reuse” category. This category encompasses Weiterverwendung ­building materials that are long-lasting, ­modular or large or for which a market exists or is expected to exist in future. Examples includeWeiterverwertung high-quality timber such as oak, ­natural Wiederverwendung stone slabs and glass facade panels, clinker Herstellerrücknahme bricks and stable and rot-proof fills such as sand and foam glass gravel. Wiederverwertung Kompostierung

If substances extracted from the breakdown Deponie Kl. I & II Weiterverwendung of a product are used for new products at the same Kl. level quality in a practically Deponie III of & VI Weiterverwertung closed utilisation loop, they are said to have Gefahrenstoff Wiederverwendung been “recycled”. This category includes all closed-loop materials: most notably metals, Herstellerrücknahme but alsoWiederverwertung biotic or mineral materials such as Verfüllung/„Landfill“ cork or loam. Deponie Kl. 0 Kompostierung Weiterverwendung Deponie Kl. I & II

Weiterverwendung

Verwertung Wiederverwendung Further Energetische use

If a used building product can be used Weiterverwertung again for a purpose other than its originally Wiederverwertung intended function at a lower-quality level, it is Herstellerrücknahme considered to be of “further use”. All ­materials that are categor­ised as reusable Weiterverwendung Wiederverwendung can, of course, also be used for a different Kompostierung purpose, possibly at a lower-quality level. Weiterverwertung Wiederverwertung Energetische Verwertung Herstellerrücknahme Weiterverwendung

Manufacturer take-back

In theseKompostierung cases the manufacturer has agreed Weiterverwertung to take back its products /materials after use in order to recycle them in a closed Verwertung productEnergetische loop. These materials are, however, Herstellerrücknahme simultaneously assigned to their alternative use categories. Kompostierung

Energetische Verwertung Weiterverwertung Deponie Kl. III & VI Gefahrenstoff Downcycling Verfüllung/„Landfill“ A substance Wiederverwendung Deponie Kl. 0that can be recovered from Herstellerrücknahme processing only in a lesser-quality form is subjected to “downcycling”. This category Deponie Kl. I & II Wiederverwertung Kompostierung includes substances such as concrete, materially reclaimable timber (e.g. unwea­ Deponie Kl. III & VI Verfüllung/„Landfill“ thered Weiterverwendung timber and waste woods that have Gefahrenstoff Deponie Kl. 0 reused),Verwertung alreadyEnergetische been and mono-material synthetics, whose utilisation in recycling ­processes associated with loss Deponie Kl.isI always & II Weiterverwertung in quality. Deponie Kl. III & VI Herstellerrücknahme Gefahrenstoff Kompostierung Composting

Although the composting of naturally grown Energetische Verwertung building materials in composting facilities is not a common practice at present, it is expected to become an option for further ­utilisation in the future.

Energetische Verwertung Energetic reclamation

If a material cannot be reutilised in material Wiederverwendung form, it is used to generate energy. Ex­ amples of such materials include weathered timber, derivedWiederverwertung wood products and biotic ­insulation that have reached the end of their utilisation cascade, as long as they are not Wiederverwendung compostable. Weiterverwendung Materials of negligible mass (adhesive strips, silicone, elastomer films Wiederverwertung and other mixed synthetic materials) are also Verfüllung/„Landfill“ Weiterverwertung energetically reclaimed. Deponie Kl. 0 Weiterverwendung Herstellerrücknahme Deponie Kl. I & II Landfill classes Weiterverwertung I and II

Deponie Kl. III & VI Kompostierung Building materials that can only be disposed Gefahrenstoff of in landfills were not used in the selected constructions.Herstellerrücknahme Energetische Verwertung Kompostierung

e

136

Energetische Verwertung

Verfüllung/„Landfill“ Deponie Kl. 0 Landfill class 0 / Fill

Inert substances (e.g. contaminated, Deponie Kl. I & slightly II unrecyclable mineral materials) that must Verfüllung/„Landfill“ be disposed of inKl. a Class 0 landfill were Deponie Deponie Kl. 0III & VI avoidedGefahrenstoff in the constructions described here. Deponie Kl. I & II Deponie Kl. III & VI Gefahrenstoff Landfill classes III and IV /  Hazardous materials

The constructions shown here contain no hazardous materials.

Verfüllung/„Landfill“ Deponie Kl. 0 Deponie Kl. I & II Deponie Kl. III & VI Gefahrenstoff Verfüllung/„Landfill“ Deponie Kl. 0 Deponie Kl. I & II Deponie Kl. III & VI Gefahrenstoff

Verfüllung/„Landfill“ Deponie Kl. 0 Deponie Kl. I & II Deponie Kl. III & VI Gefahrenstoff

The designs and constructions on the following pages were created specifically for this book. The illustrations show exclusively positive examples of Urban Mining Design: The constructions can be disassembled (see “Detachable Connections and Constructions”, p. 42ff.) and their materials can be either kept in closed material loops or take the cascading ­utilisation of renewable resources into account (see “The Recycling Potential of Building ­Materials”, p. 58ff.). In addition, a few of the projects incorporate recovered building elements or materials made from previously recycled waste (secondary raw materials). Exceptions are formed by products for which no closed-loop alternatives with the same level of performance are yet available for the intended purpose, e.g. water-impermeable concrete for cellars. The avoidance of entire building component layers – leaving the construction visible – should be considered a generally positive decision. The illustrated designs and constructions are mainly suggestions and in some cases have not been fully tested in real buildings (e.g. unvarnished window frames, basement constructions in solid timber). Information regarding regulatory requirements such as National Technical Approvals can be found in the descriptions in the chapters “Detachable Connections and Constructions” (p. 42ff.) and “The Recycling Potential of Building Materials” (p. 58ff.). The constructions were planned and designed in close consultation with an expert in structural physics. In general, it is clear that vapour-proof or vapour-tight layers (MDF or OSB panels, trapezoidal sheet metals or plastic sealings) must be sealed at their joints. In the examples, building components that are exposed to moisture over limited time periods are made from domestic timber varieties of high natural durability (without chemical wood-protecting agents) (see “The Recycling Potential of Building Materials”, p. 58ff.). Specific information on the structural physics of individual detailed designs is provided in the illustration legends. Further general challenges and problems are ­covered in greater depth in the chapter “Challenges in the Structural Design of Dismantling- and Recycling-Friendly Constructions” (p. 118f.). The loop potential of the main building elements in three of the projects, which differ from one another in the constructions of their load-bearing structure, facade, roof and foundation types, were quantitatively determined as examples. The evaluations were done using a complex assessment tool that was developed in doctoral dissertation work at the Bergische Universität Wuppertal. The methodology is explained in the chapter “Assessment of Loop Potential” on p. 114ff. The last two projects focus specifically on the challenge of building (private) bathrooms in a ­loop-compatible manner. The roof and wall base details shown in the preceding projects are not examined separately in these examples.

Constructions: Annette Hillebrandt, Petra Riegler-Floors Illustrations: Johanna-Katharina Seggewies Loop potential: Anja Rosen Structural physics: Pfeil & Koch ingenieurgesellschaft GmbH & Co. KG Michael Wengert, Tobias Edelmann Contributors: Students at the Bergische Universität Wuppertal Till Arlinghaus, Julia Blasius, Dario Gräfe, Dorothee Kaspers, Janina Meiners, Nils Nengel, Fan Ling, Nils Schäfer, Xenia Sagrebin, Charlotte Schweden, Johanna-Katharina Seggewies, Alina Weidenhaupt

137

Example 01: Steel Skeleton Construction / Stainless Steel Clip-On Panel Facade Structure and shell as a valuable investment

A real investment: stainless steel clip-on panels envelop a steel framework with trapezoidal sheet floors and roof. The high-priced, long-lasting and valuable materials are completely recyclable with no loss in quality after dismantling, and therefore represent a moneyback guarantee. The pitched roof and the facade are fitted with the same rear-ventilated system. Rain gutters and downpipes are hidden so that the reductionist angularity of the building cubage remains undisturbed. The material and the grid-like pattern of the shell intensify the disciplined appearance of the exterior. On the inside, a very different effect is achieved: the walls and ceilings are lined with old coffee sacks, likewise detachably fastened in panel form. The printing on the jute attests to the panels’ use all over the world. The mastic asphalt screed is dark; the polish on its surface brings out the little speckles of the light-coloured aggregates. Recyclable and spread over valuable copper pipes, it represents a perfect urban-mining building component. Thanks to its frost-proof and moisture-resistant properties it is also used on the balcony. As is often the case in steel skeleton structures, solid structural timber (KVH) and wood composite panels serve as a secondary construction. 138

Example 01

Partial elevation Scale 1:50 Vertical section Scale 1:20

Materials

Structure and foundation •  steel skeleton structure •  cavity insulation •  KVH secondary construction •  ground screw footings Exterior claddings •  stainless steel clip-on panels •  U-profile subconstruction Exterior floor coverings • balcony: mastic asphalt screed poured on dovetailed steel sheeting Interior claddings •  jute-lined timber framing •  metallic hook-and-loop fasteners Interior floor coverings •  floating mastic asphalt screed •  wood fibre impact sound insulation Insulation •  jute fibre insulating panels •  fibreboard insulating panels Doors / Windows •  stainless steel door frames • post-and-beam glued laminated timber / stainless steel cladding •  triple glazing •  flashings with lapped EPDM foil connections 139

a

Horizontal sections Scale 1:20 a  Ground floor section b  Upper floor section Roof construction (U-value: 0.18 W/m2K)

Exterior wall construction (U-value: 0.14 W/m2K)

Balcony door (U-value: 1.10 W/m2K)

• 1-mm stainless steel clip-on panel, clipped and secured with screws • 2 – 3-mm stainless steel U-profile subconstruction, secured with screws • 35/207-mm galvanised steel trapezoidal sheet in negative position, secured with screws • 24/48-mm untreated spruce battens, ­rear-ventilated, secured with screws • 0.2-mm high-density polyethylenene (PE-HD) windproofing sheet, diffusion-permeable, sd: 0.025 m, lapped and stapled • 15-mm tongue-and-groove MDF panels, ­diffusion-permeable, sd: 0.165 m, secured with screws • 40/60-mm untreated spruce battens, secured with screws • 60-mm jute fibre insulation panels packed between battens, 90 % recycled cacao and coffee sacks with PLA reinforcing fibres, λ: 0.038 W/mK • 200/200/9-mm galvanised steel HEB support profiles, secured with screws • 120/200-mm untreated KVH secondary ­construction, secured with screws • 200-mm jute fibre cavity insulation, 90 % recycled cacao and coffee sacks with PLA reinforcing fibres, λ: 0.038 W/mK • 22-mm OSB/3 panel with formaldehyde-free bonding agent, secured with screws • 0.2-mm low density polyethylene (PE-LD) vapour-proofing, sd: >100 m, lapped and ­stapled • 30/2.5/0.2-mm metallic hook-and-loop ­fasteners, chromium nickel steel, secured with screws on both sides • 2-mm jute fabric ceiling lining, 100 % re­ cycled, stapled onto 30/50-mm untreated spruce battens attached with metallic hookand-loop fasteners

• 1-mm stainless steel clip-on panels, clipped and secured with screws • 2 – 3-mm stainless steel U-profile subconstruction, secured with screws • 0.2-mm high-density polyethylene (PE-HD) windproofing sheeting, diffusion-permeable, sd: 0.025 m, lapped and stapled • 15-mm tongue-and-groove MDF panel, ­diffusion-permeable, sd: 0.165 m, secured with screws • 60/85-mm untreated spruce structural timber, secured with screws • 85-mm jute fibre insulation panels packed between timbers, 90 % recycled cacao and coffee sacks with PLA reinforcing fibres, λ: 0.038 W/mK • 200/75/8.5-mm galvanised steel U-support profiles, secured with screws • 120/200-mm untreated spruce KVH ­secondary construction, secured with screws • 200-mm jute fibre cavity insulation, 90 % recycled cacao and coffee sacks with PLA reinforcing fibres, λ: 0.038 W/mK • 22-mm OSB/3 panel with formaldehyde-free bonding agent, secured with screws • 0.2-mm low-density polyethylene (PE-LD) vapour-proofing, sd: >100 m, lapped and ­stapled • 30/2.5/0.2-mm metallic hook-and-loop ­fasteners, chromium nickel steel, secured with screws on both sides • 2-mm jute fabric ceiling lining, 100 % re­ cycled, stapled onto 30/50-mm untreated spruce battens attached with metallic ­hook-and-loop fasteners

• 70-mm flush-mounted stainless steel insulated frame, double-glazing • windproof flashing with lapped EPDM foil connections

Roof drip edge

• 120/150-mm stainless steel box gutter, secured with screws 140

Floor constructions

• 50-mm floating mastic asphalt screed with polished surface, with copper pipes when functioning as heating screed • 0.34-mm recycled-cellulose-fibre grey board separating sheet, loosely laid • 60-mm lignin-bonded fibreboard impact sound insulation, two layers, λ: 0.04 W/mK, loosely laid • 48.5/250-mm galvanised steel trapezoidal sheet, point-attached with screws on a ­natural rubber elastomer underlay • sand fill poured into the troughs of the trap­ ezoidal sheet • 200/200/9-mm galvanised steel HEB support profiles, secured with screws • 120/200-mm untreated spruce KVH ­secondary construction, secured with screws • 30/50-mm untreated spruce counter battens, secured with screws • 30/50-mm untreated spruce battens, secured with screws • 30/2.5/0.2-mm metallic hook-and-loop ­fasteners, chromium nickel steel, secured with screws on both sides • 2-mm jute fabric ceiling lining, 100 % re­ cycled, stapled onto 30/50-mm untreated spruce battens attached with metallic hookand-loop fasteners Balcony floor construction

Post-and-beam windows (U-value: 0.79 W/m2K)

• 50/160-mm flush-mounted glued laminated timber post-and-beam construction with stainless steel cladding, triple glazing, ­windproof flashing with lapped EPDM foil connections

• 35-mm mastic asphalt screed with polished surface • poured onto 16/34-mm dovetailed galvanised steel sheeting secured with screws • 35/50-mm galvanised steel H-support profiles, special design, secured with screws

Example 01

b

Ver De

Wiederverwendung

• 10-mm recycled polyurethane-bonded ­rubber granulate building protection matting, spot-positioned under support ­profile • 3-mm plant-based roof sealing membrane (bitumen- and halogen-free), sd: 150 m, homogeneously glued joints, loosely laid • 22-mm OSB/3 structural panels with ­formaldehyde-free bonding agent, secured with screws • 35/50-mm galvanised steel H-support ­profiles, secured with screws • 120/120/9.5-mm galvanised steel HEB ­support profiles, secured with screws • 2 – 3-mm stainless steel U-profile subconstruction, secured with screws • 1-mm stainless steel clip-on panels, clipped and secured with screws Ground floor construction (U-value: 0.23 W/m2K)

• 50-mm floating mastic asphalt screed with polished surface, with copper pipes when functioning as heating screed • 0.34-mm recycled-cellulose-fibre grey board separating sheet, loosely laid • 0.2-mm low-density polyethylene (PE-LD) vapour-proofing, sd: > 100 m, loosely laid • 60-mm lignin-bonded fibreboard impact sound insulation, two layers, λ: 0.04 W/mK, loosely laid • 100-mm pressure-resistant lignin-bonded fibreboard insulation, multiple layers, λ: 0.04 W/mK, loosely laid • 48.5/250-mm galvanised steel trapezoidal sheeting, joints rendered wind- and vapourproof with clamped natural rubber strips (µ: 10,000), point-attached with screws onto a natural rubber elastomer underlay • sand fill poured into the troughs of the trap­ ezoidal sheet • 200/200/9-mm galvanised steel HEB support profiles, secured with screws • galvanised steel ground screw foundation, secured with screws

Weiterverwendung Wiederverwendung Wiederverwertung

De Ver De De Ver Ge De

Weiterverwertung Wiederverwertung Weiterverwendung

De Ge

Wiederverwertung Wiederverwendung

Loop Potential of the Construction Materials: Recycling Path / End-of-Life Potential

Reuse

Wiederverwendung Wiederverwendung Sand fill Recycling Wiederverwertung

Wiederverwertung Steel support profiles, ground screw footings, trapezoidal Weiterverwendung sheeting, stainless steel clip-on Weiterverwendung panels with subconstruction, dovetailed sheet metal, stainWeiterverwertung Weiterverwertung less steel box gutters, metallic hook-and-loop fasteners, ­sHerstellerrücknahme tainless steel door frames, Herstellerrücknahme post-and-beam construction, Wiederverwendung Wiederverwendung used stainless steel cladding, Kompostierung ­c opper pipes, mastic asphalt Kompostierung Wiederverwertung screed Wiederverwertung Energetische Verwertung Further Use Energetische Verwertung Weiterverwendung Weiterverwendung

Downcycling Weiterverwertung

Wiederverwendung Weiterverwertung Spruce KVH, spruce battens and floor sleepers, glued Wiederverwendung ­lHerstellerrücknahme aminated timber post-andWiederverwendung Wiederverwertung Herstellerrücknahme beam constructions, OSB/3 Wiederverwertung panels, MDF panels, copper Kompostierung Wiederverwertung Weiterverwendung Kompostierung floor heating pipes, EPDM foil connectors, low-density Weiterverwendung polyethylene (PE-LD) vapourEnergetische Verwertung Weiterverwendung Weiterverwertung Energetische Verwertung proofing, rubber granulate building protection matting, Weiterverwertung plate glass Weiterverwertung Herstellerrücknahme

Verfüllung/„Landfill“ Manufacturer take-back Verfüllung/„Landfill“ Herstellerrücknahme Weiterverwendung Deponie Kl. 0 Jute fibre rubber Weiterverwertung Deponie Kl. insulation, 0 granulate building protection mattingKl. I & II Deponie Kompostierung Weiterverwertung Deponie Kl. I & II Herstellerrücknahme

De Ge

Deponie Kl. VI Deponie Kl. III III & &Verwertung VI Energetische Composting Herstellerrücknahme Gefahrenstoff Kompostierung Gefahrenstoff Jute fibre insulation, jute fabric lining, fibreboard Kompostierung Energetische Verwertung Energetic reclamation

Verfüllung/„Landfill“ Energetische Verwertung Verfüllung/„Landfill“ Grey board separating sheet, Deponie Kl. Deponie Kl. 0 0 roof sealing plant-based ­membrane, natural rubber Deponie Kl. & elastomer high-­ Deponie Kl. IIunderlay, & II II density polyethylenene Deponie III ­(PE-HD)Kl. windproofing sheet Deponie Kl. III & & VI VI Gefahrenstoff Gefahrenstoff Verfüllung/„Landfill“ Landfill class 0 / Fill Deponie Kl. 0 Verfüllung/„Landfill“ Deponie Kl. 0 Verfüllung/„Landfill“ Deponie Deponie Kl. Kl. I0& II Landfill classes I and II Deponie Kl. I & II Deponie Kl. III & VI Deponie Kl. I & II Gefahrenstoff Deponie Kl. III & VI Gefahrenstoff Deponie Kl. IIIIII&and VI IV /  Landfill classes Gefahrenstoff Hazardous materials

Herstellerrücknahme

ForHerstellerrücknahme a detailed illustration of loop potential see p. 142f.

Kompostierung

Kompostierung Kompostierung Energetische Verwertung Energetische Verwertung Energetische Verwertung

141

Materials and masses Roof 1-mm stainless steel clip-on panels 2 – 3-mm stainless steel U-profiles 35/207-mm galvanised steel trapezoidal sheeting 24 – 40/40 – 60-mm spruce battens 0.2-mm PE-HD windproofing 15-mm MDF panels 60-mm + 200-mm jute fibre insulation 200/200/9-mm galvanised steel HEB profiles 120/200-mm spruce KVH structural timber 22-mm OSB/3 panels 0.2-mm PE-HD vapour barrier 2-mm recycled jute wall lining

Materials – percentages by mass [kg/m2] 8.6 6.3 4.8 3.6 0.1 8.1 9.1 8.2 6.0 13.6 0.2 0.3

Manufacturer take-back

Compost 0.5 %

Synthetics 0.4 %

13.2 %

12.5 %

Reclamation profits (+) and disposal costs (-) by dismantling process in €/m2

Scrap metal 9.1 %

19.7 %

7.0 %

11.9 % 11.8 %

A2 timber

8.7 %

5.2 % A1 timber

€ 9.00 € 8.00 € 7.00 € 6.00 € 5.00 € 4.00 € 3.00 € 2.00 € 1.00 € 0.00 - € 1.00 - € 2.00 - € 3.00 - € 4.00 - € 5.00 + €5.78 /m2

68.9 Exterior walls 1-mm stainless steel clip-on panel 2 – 3-mm stainless steel U-profiles 0.2-mm PE-HD windproofing 15-mm MDF panels Spruce structural timbers / battens 60/85 + 30/50-mm 85 mm + 200-mm jute fibre insulation 200/200/8.5-mm galvanised steel U-profiles 120/200-mm spruce KVH structural timber 22-mm OSB/3 panels 0.2-mm PE-HD vapour barrier 2-mm recycled jute wall lining

Compost Synthetics 0.4 % 0.6 %

[kg/m2] 8.6 6.3 0.1 8.1 3.5 10.0 5.5 6.0 13.6 0.2 0.3

Manufacturer take-back Scrap metal

13.9 %

16.0 %

10.1 % 13.0 % 8.8 % 5.6 % 21.9 %

9.6 %

A2 timber

A1 timber

62.2 Floors 50-mm mastic asphalt screed Copper floor heating pipes Aluminium heating pipe plate fins 0.34-mm grey board 60-mm fibreboard impact sound insulation 48.5/250-mm galvanised steel trapezoidal sheeting Sand fill in pitches of trapezoidal sheeting 200/200/9-mm galvanised steel HEB profiles 120/200-mm spruce KVH structural timber 2≈ 30/50 spruce battens 2-mm recycled jute ceiling lining

[kg/m2] 100.0 1.5 0.5 0.2 15.0 8.8

A1 timber Compost 0.3 % 3.2 % 0.8 % 8.0 % Scrap metal 15.6 %

53.2 %

24.3 29.4 6.0 1.8 0.3

4.7 % 12.9 %

194.9

Synthetics Compost

€ 9.00 € 8.00 € 7.00 € 6.00 € 5.00 € 4.00 € 3.00 € 2.00 € 1.00 € 0.00 - € 1.00 - € 2.00 - € 3.00 - € 4.00 - € 5.00

0.3 % 0.8 %

0.1 %

Asphalt

12.6 % 1.6 %

16.3 %

51.3 %

4.5 % Scrap metal

12.5 % Soil Rounding differences in the ­diagrams are software-related

142

+ €5.42 /m2

+ €4.24 /m2

[kg/m2]

50-mm mastic asphalt screed 100.0 Copper floor heating pipes 1.5 Aluminium heating pipe plate fins 0.5 0.34-mm grey board 0.2 0.2-mm PE-HD vapour barrier 0.2 60-mm + 100-mm fibreboard insulation 24.6 Sand fill in pitches of trapezoidal sheeting 24.3 48.5/250-mm galvanised steel trapezoidal 8.8 sheeting 200/200/9-mm galvanised steel HEB profiles 31.7 1600-mm galvanised steel ground 3.1 screw footings

Asphalt

Soil

187.9

Ground slab / Foundation

1.0 %

€ 9.00 € 8.00 € 7.00 € 6.00 € 5.00 € 4.00 € 3.00 € 2.00 € 1.00 € 0.00 - € 1.00 - € 2.00 - € 3.00 - € 4.00 - € 5.00

€ 9.00 € 8.00 € 7.00 € 6.00 € 5.00 € 4.00 € 3.00 € 2.00 € 1.00 € 0.00 - € 1.00 - € 2.00 - € 3.00 - € 4.00 - € 5.00

+ €4.35 /m2

Example 01

Global Warming Potential (GWP) in kg CO2eq /m2 120 100 80 60 40 20 0 -20 -40 -60 -80

Loop potential of the construction

Loop potential for the steel skeleton construction / stainless steel clip-on panel example

52.5 % 26.3 %

+ -

Pre-use

Post-use 8.4 % 10.4 %

43.7 %

3)

4)

4)

) ies D ilit ng ( b i l a li yc e a tur os nd ec em fac ac isp sa mr l t u i D p f n fro ne Re Ma Be 1–

A e(

nts

(B

3–

l (C

20.6 % 7.8 %

Pre-use

Post-use

Total

Closed-loop potential

70.0 %

80.9 %

150.9 %

Loop potential

70.0 %

99.7 %

169.7 %

Jute fibre insulation not included due to lack of data

120 100 80 60 40 20 0 -20 -40 -60 -80

47.4 % 26.1 %

+ -

Pre-use

Post-use 9.4 %

48.4 %

3)

4)

nts

(B

3–

l (C

8.6 %

4)

) ies D ilit ng ( b i l a li yc e a tur os nd ec em fac ac isp sa mr l t u i D p f n fro ne Re Ma Be 1–

A e(

22.6 %

11.5 %

Pre-use

Post-use

Total

Closed-loop potential

74.5 %

78.6 %

153.1 %

Loop potential

74.5 %

99.5 %

174.0 %

Jute fibre insulation not included due to lack of data

120 100 80 60 40 20 0 -20 -40 -60 -80

12.9 %

+ -

Pre-use 12.2 % 8.1 %

)

4)

4)

) ies D ilit g ( iab yclin l d c os em ctu an re isp lac ufa its rom D p f n e e f n R Ma Be –3

A1

( re

ts en

(B

3–

(C al

Post-use

1.5 % 8.5 % 0.7 % 3.5 %

72.6 %

Pre-use

Post-use

Total

Closed-loop potential

20.3 %

89.7 %

110.0 %

Loop potential

20.3 %

99.8 %

120.1 %

The use of valuable materials is reflected in the diagrams of all the building elements. The ex­ terior wall and roof contain about one third, by mass, of the steel and stainless steel materials. The ferrous metals, which consist of about 35 % secondary materials, command a high scrap value at the end of the building components’ service lifetimes. Although the mastic asphalt screed is entirely made from non-renewable primary materials, it surrounds a true treasure: The copper heating pipes make up only a ­relatively small fraction of the floor and ground building components, but their scrap value is very high. The selective dismantling of the screed is therefore worth the effort for its “contained” value alone. Melting the asphalt allows the copper to be separated from it easily and then sent on to be recycled, while the screed itself can be repoured. Because of the value of the metals and the ease of separation, select­ ive dismantling is absolutely economical, with the result that the metals enter into the postuse portion of the loop potential at a 1:1 ratio and the screed at 0.9 (because of the work-­ intensive dismantling process). The sand used as bulk fill in the floors can be reused directly. The jute fibre insulation consists of 88 % secondary material, and it can be defibered and reutilised in the pro­ duction of new fibre mats (manufacturer takeback process). The manufacture of the incorporated metals is extremely energy-intensive and produces climate-damaging greenhouse gases (Module A of the Life Cycle Assessment). However, recycling the metals at the end of their service lifetime reduces emissions in comparison to the use of primary raw materials, resulting in a credit that is exported into the next life cycle (Module D). No life cycle assessment data exist for the high-grade recycling of mastic asphalt screed, so that in this case only construction waste processing can be applied in Module C. Credits for the entire construction would in actual fact be higher. As for the timber materials used, the explanations given for the constructions on p. 157f. apply. Loop potential key Pre-use Recycled materials (MRC, see B 2.4a p. 64) Regrown raw materials

120 100 80 60 40 20 0 -20 -40 -60 -80

12.5 %

+ -

Pre-use

2.4 %

12.6 %

Post-use Post-use

76.6 %

8.2 %

8.6 %

)

4)

4)

) ies D ilit g ( iab yclin l d c os em ctu an re isp lac ts om ufa i D p f n r f ne Re Ma Be –3

A1

( re

ts en

(B

3–

(C al

Pre-use

Post-use

Total

Closed-loop potential

21.2 %

89.1 %

110.3 %

Loop potential

21.2 %

99.7 %

120.9 %

Reusable materials Recyclable materials Downcyclable materials from certifiably ­sustainable renewable sources Energetically recoverable materials from ­certifiably sustainable renewable sources Downcyclable materials Energetically recoverable materials from renewable sources

143

Example 02: Steel Skeleton Construction / Glass Ceramics Panel Facade Structure 100 % recyclable – shell made of 100 % recycled material

The structure of the shell material reveals its origins: rounded glass fragments seem to float in the surrounding melt. The elegant facade panels are made of 100 % recycled glass, their colours inviting guesses as to its former function: did it come from window panes, perhaps, or bottles? Owing to their large format and longevity, the panels might themselves be reused someday. Fittingly, although they are not visible from the outside, the insulation panels are made from foam glass and recycled bottle corks. Both the primary and the secondary construction are made of steel, an investment in the urban mine concept. In the interior, loam structural panels, reinforced with a flax mesh and entirely free of synthetic substances, are covered with loam plaster and a fine loam mortar. Much like the finished mastic asphalt screed, they will have no need of surface coverings for a long time to come. The openings draw attention to the strength of the wall. Opaque ventilation flaps and transparent window glazing framed in steel alternate between exterior and interior flushmounting and create a sculptural appearance. A roof covering of water-coloured recycled glass gravel completes the glazed shell as its fifth facade. 144

Example 02

Partial elevation Scale 1:50 Vertical section Scale 1:20

Material

Support structure and foundation • steel skeleton construction •  cavity insulation •  solid timber (KVH) secondary construction •  ground screw footings Exterior cladding •  glass ceramic panels •  aluminium rectangular tubes Interior cladding •  loam structural panels with loam plaster • battens Interior floor coverings • mastic asphalt screed, floating • floor heating system panels with wood fibre insulation Insulation •  foam glass panels •  foam glass gravel insulating fill •  cork insulating panels •  granulated cork fill •  fibreboard insulation Doors / Windows •  stainless steel frames •  triple glazing •  flashing with lapped EPDM connecting foils 145

a Horizontal sections Scale 1:20 a  Ground floor section b  Upper floor section Roof construction (U-value: 0.12 W/m2K)

Exterior wall construction (U-value: 0.16 W/m2K)

Interior wall construction

• 30 –70-mm 100 % recycled glass gravel bed • 2-mm 100 % EPDM roof sealing membrane, sd: 140 m, uniformly bonded at overlapping seams, loosely laid • 200-mm 70 % recycled foam glass panel insulation, two layers, with additional 40 – 90-mm tapered insulation layer, λ: 0.038 W/mK, floating • 35/207-mm galvanised steel trapezoidal sheet in negative position, overlapped joints rendered wind- and vapour-proof with clamped natural rubber strips (µ: 10,000), point-attached with screws onto a natural rubber elastomer underlay • 98 % foam glass gravel fill, λ: 0.1 W/mK, poured loosely into the troughs of the trap­ ezoidal sheet • 1810/180/8.5-mm galvanised steel HEB ­support profiles, secured with screws • 40/60-mm untreated spruce counter battens, secured with screws • 40/60-mm untreated spruce battens as ­interior facing, secured with screws • 25-mm loam structural panels with loam ­plaster and loam mortar, flax reinforcing mesh, Q3 surface finish, secured with screws

• 22-mm 100 % recycled glass ceramic panels, invisibly attached by undercut anchors to agraffe profiles • 40/30/20-mm aluminium rectangular tube, secured to L-profile with screws • 15-mm tongue-and-groove MDF panels, vapour-permeable, sd: 0.165 m, secured with screws • 40/80-mm untreated spruce structural timber, secured with screws • 80-mm 100 % cork insulating panels between beams, λ: 0.037 W/mK • 180/180/8.5-mm galvanised steel HEB ­support profiles, secured with screws • 180/70/8-mm secondary construction of ­galvanised steel fi support profiles, secured with screws • 180-mm granulated cork fill cavity insulation from 100 % recycled bottle corks, λ: 0.045 W/mK • 10-mm fibreboard, wood from sustainably managed forests, sd: 1.6 m, airtight bonding at joints, secured with screws • 40/60-mm untreated spruce battens as ­interior facing, secured with screws • 25-mm loam structural panels with loam ­plaster and loam mortar, flax reinforcing mesh, Q3 surface finish, secured with screws

• 25-mm loam structural panels with loam ­plaster and loam mortar, flax reinforcing mesh, Q3 surface finish, secured with screws • 40/60-mm untreated spruce battens as ­interior facing, secured with screws • 10-mm fibreboard, wood from sustainably managed forests, sd: 1.6 m, airtight bonding at joints, secured with screws • 100/60-mm untreated solid timber (KVH) frames • 100-mm granulated cork fill cavity insulation from 100 % recycled bottle corks, λ: 0.045 W/mK, factory-prefabricated • 10-mm fibreboard, wood from sustainably managed forests, sd: 1.6 m, airtight bonding at joints, secured with screws • 40/60-mm untreated spruce battens as ­interior facing, secured with screws • 25-mm loam structural panels with loam ­plaster and loam mortar, flax reinforcing mesh, Q3 surface finish, secured with screws

Roof drip edge

• 2-mm E6/EV1 anodised aluminium flat roof drip edge profile, tilted, clamped onto cor­ responding retainer element which is screwed onto untreated timber board

146

Windows (U-value: 0.90 W/m2K)

• 70-mm stainless steel window frames, inner / outer flush mounting, triple glazing, stainless steel ventilation flaps • 70-mm 100 % cork insulating panels between panes, λ: 0.037 W/mK, windproof flashing with lapped EPDM connecting foils

Floor construction

• 35-mm mastic asphalt screed with polished surface, with copper pipes when functioning as heating screed, floating • 0.34-mm grey board separating sheet from recycled cellulose fibres, loosely laid • 40-mm lignin-bonded fibreboard impact sound insulation, λ: 0.04 W/mK, loosely laid • 15-mm tongue-and-groove MDF panel, vapour-permeable, sd: 0.165 m, secured with screws • 48.5/250-mm galvanised steel trapezoidal sheeting, point-attached with screws onto a ­natural rubber elastomer underlay

Example 02

b

Ver De

Wiederverwendung

• sand fill poured loosely into the troughs of the trapezoidal sheeting • 180/180/8.5-mm galvanised steel HEB ­support profile, secured with screws • 40/60-mm untreated spruce counter battens, secured with screws • 40/60-mm untreated spruce battens as ­interior facing, secured with screws • 25-mm loam structural panels with loam ­plaster and loam mortar, flax reinforcing mesh, Q3 surface finish, secured with screws Ground floor construction (U-value: 0.23 W/m2K)

• 35-mm mastic asphalt screed with polished surface, with copper pipes when functioning as heating screed, floating • 0.34-mm grey board separating sheet from recycled cellulose fibres, loosely laid • 80-mm lignin-bonded fibreboard impact sound insulation, double layer, λ: 0.04 W/mK, loosely laid • 15-mm tongue-and-groove MDF panels, vapour-permeable, sd: 0.165 m, secured with screws • 180/180/8.5-mm galvanised steel HEB ­support profile, secured with screws • 35/207-mm galvanised steel trapezoidal sheet in negative position, overlapped joints rendered wind- and vapour-proof with clamped natural rubber strips (µ: 10,000), point-attached with screws onto a natural rubber elastomer underlay • 160-mm granulated cork fill cavity insulation from 100 % recycled bottle corks, λ: 0.045 W/mK, loosely filled into trape­z­ oidal sheeting • galvanised steel ground screw footings, screwed into the ground

Ver De Ver De De De Ge De De Ge De

Wiederverwendung Wiederverwertung Wiederverwendung

Loop Potential of the Construction

Wiederverwertung Weiterverwendung

Materials: Recycling Path / End-of-Life Potential Wiederverwertung

Reuse

Wiederverwendung Glass ceramic panels, sand fill, foam glass gravel insulating fill, Wiederverwendung glass gravel fill Wiederverwertung Recycling

Wiederverwertung Weiterverwendung Granulated cork insulating fill, cork insulating panels, steel support profiles, ground Weiterverwendung Weiterverwertung screw foundation, trapezoidal sheeting, aluminium subconWeiterverwertung struction and profiles, stainless Herstellerrücknahme steel window frames, copper floor heating pipes, mastic Herstellerrücknahme asphalt screed, glass ceramic Kompostierung panels, foam glass insulating Wiederverwendung Wiederverwendung gravel fill and panels, loam Kompostierung Energetische Verwertung structural panels Wiederverwertung Wiederverwertung Wiederverwendung Wiederverwendung Energetische Verwertung Wiederverwendung Further use

Weiterverwendung Weiterverwendung Wiederverwertung Wiederverwertung Wiederverwertung Downcycling Weiterverwertung Weiterverwertung Weiterverwendung Spruce solid timber (KVH), Weiterverwendung Weiterverwendung spruce battens, MDF panels, Herstellerrücknahme EPDM roof sealing membrane, Herstellerrücknahme Weiterverwertung Weiterverwertung EPDM connecting foils, plate Weiterverwertung glass Kompostierung Kompostierung Herstellerrücknahme Herstellerrücknahme Herstellerrücknahme

Weiterverwendung Weiterverwertung Weiterverwendung Manufacturer take-back Verfüllung/„Landfill“ Weiterverwertung Herstellerrücknahme Deponie Kl. 0sealing EPDM roof Weiterverwertung membrane Verfüllung/„Landfill“ Herstellerrücknahme Deponie Kl. 0 I & II Kompostierung

Ge

Herstellerrücknahme Composting Deponie Kl. IIII&&II VI Kompostierung Energetische Verwertung Fibreboard insulation Gefahrenstoff Kompostierung Deponie Kl. III & VI Energetische Verwertung Gefahrenstoff Energetic reclamation Energetische Verwertung Grey board separating

sheet, plant-based roof ­sealing membrane, ­natural ­rubber strips, natural ­rubber elastomer Verfüllung/„Landfill“ Verfüllung/„Landfill“ underlay, adhesive tape Deponie Deponie Kl. Kl. 0 0 Deponie II & II Verfüllung/„Landfill“ Landfill Kl. class Deponie Kl. &0 / Fill II Verfüllung/„Landfill“ Verfüllung/„Landfill“ Deponie Kl. 0 Deponie Kl. Kl. 0 0 Deponie Deponie Kl. Kl. III III & & VI VI Deponie Gefahrenstoff Landfill classes Deponie Kl. II & &I and II II Gefahrenstoff Deponie Kl. Deponie Kl. I & II II Deponie Kl. III & VI Deponie Kl. VI Deponie Kl. III IIIIII& &and VI IV / Landfill classes Gefahrenstoff Gefahrenstoff Gefahrenstoff ­Hazardous materials

Energetische Verwertung Energetische Verwertung Kompostierung Kompostierung Kompostierung Energetische Verwertung Verwertung Energetische Energetische Verwertung

147

Example 03: Steel Skeleton Construction / Natural Stone Panel Facade Detachably fastened reusable long-lasting facade

The travertine in the facade comes from a regional quarry. The plate heights vary from layer to layer, making the natural banding of sedimentary rock a thematic element of the shell. The facade panels are mechanically fixed onto spring-tensioned metal clamps via factory-milled slits on their backs, and mounted by concealed means onto an aluminium subconstruction. The panels can be individually replaced, facilitating repairs. The commonly used undercut anchors, which must be bonded to the stone, are avoided, allowing for 1:1 reusability of the facade materials. As a contrast to the regional, textural natural stone, globally available float glass in a special structurally glazed format is installed flush with the building surface. To do this, the inwardfacing sides of the glass panes are factoryglued onto subconstruction moulding and then screwed onto the post-and-beam construction on-site. The unusual fact that the posts and beams are made from glued laminated timber contributes significantly to reducing the facade’s carbon footprint. On the inside of the building, textile surfaces of robust sisal combined with soft wool felt characterise the look. 148

Example 03

Partial elevation Scale 1:50 Vertical section Scale 1:20

Materials

Support structure and foundation •  steel skeleton construction •  cavity insulation •  KVH structural timber secondary construction •  ground screw footings Exterior cladding •  natural stone • aluminium subconstruction  Exterior floor coverings • natural stone terrace pavers • tile-levelling spindles Interior cladding • sheep’s wool felt lining   • metallic hook-and-loop fastener  Interior floor coverings • sisal carpet on gypsum fibreboard dry screed • floor heating system panels with wood fibre insulation Insulation • coconut fibre insulation panels  • fibreboard insulation Doors / Windows • glued laminated post-and-beam structural glazing • triple glazing  • flashings with lapped EPDM connecting foils  149

a Roof construction (U-value: 0.18 W/m2K)

• 30-mm regional travertine stone panels, ­random structure, laid on • 80-mm galvanised steel tile-levelling spindles • 10-mm polyurethane-bonded recycled rubber granulate building protection matting, spotlaid under levelling spindles • 2-mm 100 % EPDM roof sealing membrane, sd: 140 m, uniformly bonded at overlapping seams, loosely laid • 160-mm lignin-bonded fibreboard insulation, multiple layers with additional 40 – 90-mm graded layer, λ: 0.04 W/mK, floating • 48.5/250-mm galvanised steel trapezoidal sheet in positive position, overlapped joints rendered wind- and vapour-proof with clamped natural rubber strips (µ: 10,000), point-attached with screws onto a natural rubber elastomer underlay • bulk sand fill poured loosely into the troughs of the trapezoidal sheeting • 200/200/9-mm galvanised steel HEB support profiles, secured with screws • 2-mm aluminium C-profile subconstruction, secured with screws  • 12.5-mm gypsum fibreboard panels, secured with screws • 30/2.5/0.2-mm metallic hook-and-loop ­fasteners, chrome nickel steel, secured with screws and sewn • 5 mm sheep’s wool felt ceiling lining, attached via metallic hook-and-loop fasteners Exterior wall construction (U-value: 0.14 W/m2K)

• 30-mm regional travertine stone panels, ­random structure, clamped • 3-mm dark-anodised aluminium subconstruction of vertical profiles and spring clamps, secured with screws 150

b

• 15-mm tongue-and-groove MDF panel, vapour-permeable, sd: 0.165 m, secured with screws • 55/90-mm untreated structural timber, secured with screws • interspersed with 90-mm lignin-bonded ­fibreboard insulation, λ: 0.04 W/mK • 200/200/9-mm galvanised steel HEB support profiles, secured with screws • 200-mm flax fibre mat cavity insulation, borate-free with biological bonding agents, λ: 0.04 W/mK • 25-mm OSB/3 panels, with formaldehydefree bonding agents, secured with screws • 3-mm aluminium C-profiles, secured with screws • interspersed with 50-mm flax fibre mat cavity insulation, borate-free with biological bonding agents, λ: 0.04 W/mK • 12.5-mm straw panels, two layers, compressed wheat straw core with cardboard facing, no bonding agents, secured with screws • 30/2.5/0.2-mm metallic hook-and-loop ­fasteners, chrome nickel steel, secured with screws and sewn • 5-mm sheep’s wool felt wall lining, attached via metallic hook-and-loop fasteners Window post-and-beam (U-value: 0.69 W/m2K)

• 60/200-mm glued laminated timber postand-beam construction, flush-mounted on exterior; triple glazing factory-glued onto ridged, birch-laminated plywood coupling strip with 2-component silicone and screwed onto post-and-beam • windproof flashing with lapped EPDM ­connecting foils

Terrace and balcony door (U-value: 0.69 W/m2K)

• 60/200-mm glued laminated timber postand-beam construction with aluminium ­capping strip, flush-mounted on exterior; ­triple glazing, windproof flashing with lapped EPDM connecting foils, ridged ­plywood ­coupling strip with glued-on glass, screwed onto post-and-beam Floor construction

• 6-mm carpet, looped sisal fibre with cotton backing, spot-attached with double-sided adhesive tape • 12.5-mm gypsum fibreboard dry screed, two layers glued and screwed together • 30-mm fibreboard insulation floor heating panels with aluminium thermal conducting sheeting and PE-RT /aluminium alloy floor ­heating pipes, floating • 50-mm cardboard honeycomb panels with cardboard facing on underside, floating • bulk sand fill poured loosely into the honeycomb cells • 25-mm OSB/3 panels, two layers, made with formaldehyde-free bonding agents, secured with screws • 200/200/9-mm galvanised steel HEB support profile, secured with screws • 80/160-mm untreated spruce KVH structural timber, secured with screws • 2-mm aluminium C-profile subconstruction, secured with screws • 12.5-mm gypsum fibreboard panels, secured with screws • 30/2.5/0.2-mm metallic hook-and-loop ­fasteners, chrome nickel steel, secured with screws and sewn • 5-mm sheep’s wool felt ceiling lining, attached via metallic hook-and-loop fasteners

Example 03

Horizontal sections Scale 1:20 a  Ground floor section b  First floor section c  Second floor section

Loop Potential of the Construction Materials: Recycling Path / End-of-Life Potential

Verfüll Depon Verfüll Depon Depon

Reuse

Wiederverwendung Natural stone panels, sand fill Wiederverwendung Wiederverwertung

Recycling

Wiederverwertung Steel support profiles, ground Weiterverwendung screw foundation, trapezoidal sheeting, aluminium subconstrucWeiterverwendung tion and clamps, metallic hookWeiterverwertung and-loop fasteners, aluminium post-and-beam capping strips, Weiterverwertung ­aHerstellerrücknahme luminium thermal conduction sheeting, steel levelling spindles, Wiederverwendung Wiederverwendung Herstellerrücknahme aluminium vapour-proofing, ­gKompostierung ypsum fibreboard, cardboard Wiederverwertung honeycomb panels Wiederverwertung Kompostierung

Depon Depon Gefahr Depon Gefahr

Energetische Verwertung Further use

Depon Depon Gefahr Gefahr

Verfüll Verfüll Depon Depon

Depon Depon

Weiterverwendung Weiterverwendung Energetische Verwertung

c Floor construction with exterior exposure (U-value: 0.15 W/m2K)

• 6-mm carpet, looped sisal fibre with cotton backing, spot-attached with double-sided adhesive tape • 12.5-mm gypsum fibreboard dry screed, two layers glued and screwed together • 30-mm fibreboard insulation floor heating panels with aluminium thermal conducting sheeting, floating • 50-mm cardboard honeycomb panels with cardboard facing on underside, floating • bulk sand fill poured loosely into the honeycomb cells • 25-mm OSB/3 panels, two layers, made with formaldehyde-free bonding agents, secured with screws • 200/200/9-mm galvanised steel HEB support profiles, secured with screws • 80/160-mm untreated spruce KVH structural timber, secured with screws • 200-mm flax fibre mat cavity insulation, borate-free with biological bonding agents, λ: 0.04 W/mK • 55/90-mm untreated structural timber, secured with screws • interspersed with 55-mm lignin-bonded ­fibreboard insulation, λ: 0.04 W/mK • 15-mm tongue-and-groove MDF panels, vapour-permeable, sd: 0.165 m, secured with screws • 3-mm subconstruction of aluminium vertical profiles and clamps, secured with screws • 30-mm natural limestone panels, random structure, clamped

Ground floor construction (U-value: 0.20 W/m2K)

• 6-mm carpet, looped sisal fibre with cotton backing, spot-attached with double-sided adhesive tape • 12.5-mm gypsum fibreboard dry screed, two layers glued and screwed together • 30-mm fibreboard insulation floor heating panels with aluminium thermal conducting sheet and PE-RT /aluminium alloy floor ­heating pipes, floating • 0.05-mm coarse-grained aluminium ­vapour-proofing foil, sd: > 2,500 m, loosely laid • 130-mm lignin-bonded compression-­ resistant fibreboard insulation, multiple ­layers, λ: 0.04 W/mK, floating • 50-mm cardboard honeycomb panels with cardboard facing on underside, floating • bulk sand fill poured loosely into the honeycomb cells • 48.5/250-mm galvanised steel trapezoidal sheet in positive position, overlapped joints rendered wind- and vapour-proof with clamped natural rubber strips (µ: 10,000), point-attached with screws onto a natural rubber elastomer underlay • bulk sand fill poured loosely into the troughs of the trapezoidal sheeting • 200/200/9-mm galvanised steel HEB support profiles, secured with screws Wiederverwendung Wiederverwendung • galvanised steel ground screw footings, Wiederverwendung screwed into the ground

Downcycling Weiterverwertung

Weiterverwertung Spruce KVH structural timber, Wiederverwendung spruce battens and floor sleepers, glued laminated timber post-andHerstellerrücknahme Herstellerrücknahme beam, OSB/3 panels, MDF panels, Wiederverwertung sheep’s wool felt lining, floor heatWiederverwendung Kompostierung Kompostierung ing pipe alloy, EPDM connecting foils, EPDM roof sealing memWeiterverwendung Wiederverwertung brane, rubber granulate building Energetische Verwertung Wiederverwendung Energetische Verwertung protection matting, glass panes Weiterverwertung Weiterverwendung Wiederverwertung Manufacturer take-back

Herstellerrücknahme Straw panels, EPDM roof sealing Weiterverwertung Weiterverwendung membrane, rubber granulate ­bKompostierung uilding protection matting Herstellerrücknahme Weiterverwertung Kompostierung Straw panels, fibreboard insulaHerstellerrücknahme tion, flax fibre insulating panels, sisal carpet Verwertung Energetische Kompostierung Energetic reclamation

Energetische Natural rubber Verwertung strips, natural ­rubber elastomer underlay, ­adhesive tape Landfill class 0 / Fill Verfüllung/„Landfill“ Verfüllung/„Landfill“

Verfüllung/„Landfill“ Deponie Kl. Deponie Kl. Kl. 00 0 Deponie

Landfill classes Deponie Kl. I I&and II II

Weiterverwendung Weiterverwendung Weiterverwendung

Landfill classes Deponie Kl. IIIIII&and VI IV / Gefahrenstoff Gefahrenstoff Gefahrenstoff materials Hazardous

Deponie Kl. Kl. II & & II II Deponie

Deponie Kl. Kl. III III & & VI VI Deponie

Weiterverwertung Weiterverwertung Weiterverwertung Herstellerrücknahme Herstellerrücknahme Herstellerrücknahme Kompostierung Kompostierung

Depon Verfüll Depon Depon Gefahr Depon Verfüll

Depon Depon Gefahr Depon

Depon Gefahr

Energetische Verwertung Composting

Wiederverwertung Wiederverwertung Wiederverwertung

Verfüll Depon

151

Example 04: Timber Panel Construction / Larch and Copper Shingle Facade Naturally ageing shingle textures

The building is characterised by the shingle cladding on the exterior shell. Most of the surface is covered with small larch shingles, while the recessed entry features copper shingles – a combination of renewable resources and economically employed high-value material in an urban mine. Both materials undergo authentic ageing processes during which they change colour, although at different rates. The longer-lasting copper sheet is also used as cladding in the area near the foundation that is exposed to water spray. The copper facade elements under the protective overhang will develop a different patina than the ones exposed to the weather, visually reflecting the ageing process. The windows in the recessed, shaded section are mounted flush with the outer wall surface and feature a window bench inside. The upper-storey windows are flush with the interior of the wall, so that the resulting deep soffits provide their own shade for passive sun protection. The roof terrace decking forms an even plane with the parapet coping. A circumferential gap for cleaning and maintenance inspections fulfils building code requirements for flat roofs. The material and partitioning of the terrace balustrade complete the visual elegance of the overall design. 152

Example 04

Partial elevation Scale 1:50 Vertical section Scale 1:20

Materials

Support structure and foundation •  prefabricated timber panels •  cavity insulation •  prefabricated timber beam floors •  ground screw footings Exterior cladding •  wood shingles •  on battens •  copper shingles •  on formwork Exterior floor coverings •  black locust terrace decking •  timber grating •  steel subconstruction Interior cladding • loam structural panels with loam plaster ­interior finish •  click-lock cork flooring •  floor batten subconstruction Insulation •  cellulose insulation •  fibreboard insulation Doors / Windows •  oak frames •  triple glazing •  flashing packed with loose hemp wool 153

a Roof construction (U-value: 0.12 W/m2K)

Exterior wall construction (U-value: 0.16 W/m2K)

Upper storey windows (U-value: 0.70 W/m2K)

• 1,000-mm galvanised flat steel balustrade with tensioned stainless steel cables, secured with screws • 60/140/7-mm galvanised steel fi support profiles, secured with screws • 150/30-mm untreated and planed black locust terrace decking, secured with screws • 40/90-mm untreated and planed black locust support beams, secured with screws • 100/55/4.1-mm galvanised steel Å deck ­supports, secured with screws • steel levelling spindles, height-adjustable • 10-mm building protection matting, polyur­ ethane-bonded recycled rubber granulate, spot-placed under levelling spindles • 3-mm plant-based roof sealing membrane, multiple layers, bitumen- and halogen-free, sd: 150 m, uniformly bonded at overlapping seams, loosely laid • 180-mm lignin-bonded fibreboard insulation, multiple layers with additional 70 –140 mm graded layer, λ: 0.04 W/mK, loosely laid • 0.05-mm coarse-grained aluminium vapourproofing foil, sd: > 2,500 m, loosely laid, airtight adhesive joining at seams, mechanically fastened to parapet with aluminium profile • 15-mm OSB/3 panels, with formaldehydefree bonding agents, secured with screws • 120/260-mm untreated glued laminated ­timber ceiling beams • 40/60-mm untreated spruce battens as ­interior facing, secured with screws • 25-mm loam structural panels with loam ­plaster and loam mortar, flax reinforcing mesh, Q3 surface finish, secured with screws

Cladding 1: Wood shingles • 20-mm untreated split larchwood shingles, two layers, secured with screws • 40/60-mm untreated spruce battens, secured with screws • 40/60-mm untreated spruce counter battens, secured with screws 15-mm tongue-and-groove MDF panels, •  vapour-permeable, sd: 0.165 m, secured with screws Cladding 2: Copper shingles • 0.7-mm recycled copper shingles, crimped, nailed • 18-mm untreated spruce formwork, secured with screws • 40/60-mm untreated spruce counter battens, secured with screws • 15-mm tongue-and-groove MDF panels, vapour-permeable, sd: 0.165 m, secured with screws Wall construction • 60/60-mm untreated spruce structural timber, secured with screws • interspersed with 60 mm insulation from waste paper cellulose fibres, λ: 0.04 W/mK, blown in • 5-mm fibreboard, 97 % wood ,sd: 0.06 m, secured with screws • 80/160-mm untreated spruce KVH solid ­timber framing • interspersed with 160-mm cellulose cavity insulation from waste paper, λ: 0.04 W/mK, blown in • 8-mm fibreboard, sd: 1.48 m, airtight bonding at joints, secured with screws • 24/60-mm untreated spruce counter battens, secured with screws • 40/60-mm untreated spruce battens as ­interior facing, secured with screws • 25-mm loam structural panels with loam ­plaster and loam mortar, flax reinforcing mesh, Q3 surface finish, secured with screws

• 78-mm oak frames mounted flush with ­interior wall surface, treated with oil on ­outside, untreated inside; triple glazing, ­windproof flashing packed with loose hemp wool • 0.7-mm copper outer shell and window sill sheet, crimped and nailed • 50-mm cavity insulation, 100 % cork insulating panels, λ: 0.037 W/mK • 8-mm impact-rated laminated safety glass, 2≈ 4-mm, seated in groove by plug connection, easily replaceable

Roof drip edge

• 2-mm copper parapet coping, tilted, clamped onto retainer and secured with screws • tapered untreated spruce board, secured with screws 154

Entry door / ground floor windows (U-value: 0.70 W/m2K)

• 78-mm oak framed windows/entry door mounted flush with exterior wall surface, treated with oil on outside, untreated inside; triple glazing, windproof flashing with loose hemp wool • jambs and window bench of 35-mm oiled ­plywood panels • 60-mm hemp fibre mat cavity insulation with PLA reinforcing fibres, λ: 0.04 W/mK Floor constructions

• 10.5-mm click-lock cork floor tiles: HDF ­support panels, cork overlay, cork counter layer, secured with screws • 30/60-mm untreated spruce floor sleepers • interspersed with 60-mm lignin-bonded ­fibreboard impact sound insulation, double layer, λ: 0.04 W/mK, floating • 2-mm cork underlay for acoustic ­decoupling, stapled • 30-mm solid silver fir timber diagonal-board panels, individual boards connected with one another via dovetail joints, secured with screws • 140/280-mm untreated spruce glued ­laminated timber ceiling beams

Example 04

Horizontal sections Scale 1:20 a  Ground floor section b  Upper floor section

Ver De Ver

Wiederverwendung Wiederverwendung

De De

Wiederverwertung

De De Ge De

Wiederverwertung Weiterverwendung

b

• interspersed with 100 mm sheep’s wool sound insulation matting, λ: 0.039 W/mK • 40/60-mm untreated spruce battens as ­interior facing, secured with screws • 25-mm loam structural panels with loam ­­plaster and loam mortar, flax reinforcing mesh, Q3 surface finish, secured with screws Ground floor construction (U-value: 0.17 W/m2K)

• 10.5-mm click-lock cork floor tiles: HDF ­support panels, cork overlay, cork counter layer, secured with screws • 30/60-mm untreated spruce floor sleepers • interspersed with 60-mm lignin-bonded ­fibreboard impact sound insulation, ­double layer, λ: 0.04 W/mK, floating ­installation • 2-mm cork underlay for acoustic ­decoupling, stapled • 8-mm fibreboard, sd: 1.48 m, airtight bonding at joints, secured with screws • 30-mm solid silver fir timber diagonal-board panels, individual boards connected with one another via dovetail joints, secured with screws • 140/200-mm untreated spruce glued lamin­ ated timber beams • interspersed with 200-mm cellulose cavity insulation from waste paper, λ: 0.039 W/mK, factory-installed • 22-mm timber formwork, wood use class 2 (DIN 68 800-1), durability class 2 (DIN EN 35), e.g. pine / scots pine, oak, sd: 0.88 m, tongue-and-groove jointed, secured with screws • 70/70/7-mm galvanised steel support ­profiles, point-attached with screws onto a ­natural rubber elastomer underlay • galvanised steel ground screw footings

Weiterverwendung

Loop Potential of the Construction Materials: Recycling Path / End-of-Life Potential

Reuse

Wiederverwendung Wiederverwendung Recycling Wiederverwertung Wiederverwertung Cork insulating panels, steel profiles, ground screw foun­ Weiterverwendung dation, steel balustrade, Weiterverwendung ­stainless steel levelling ­spindles, copper shingles, Wiederverwendung Wiederverwendung Weiterverwertung Weiterverwertung copper parapet coping, ­aluminium vapour-proofing, Wiederverwertung loam structural panels Wiederverwertung Herstellerrücknahme Herstellerrücknahme Further use

Weiterverwendung Weiterverwendung Kompostierung Kompostierung Wiederverwendung Wiederverwendung Wiederverwendung Downcycling Weiterverwertung Weiterverwertung Energetische Verwertung Spruce KVH, solid timber Energetische Verwertung Wiederverwendung Wiederverwertung ­diagonal-board panels, spruce Wiederverwertung Wiederverwertung Herstellerrücknahme battens, oak window frames, Herstellerrücknahme Wiederverwertung Weiterverwendung glued laminated timber planks, OSB/3 panels, fibreboard, Weiterverwendung Weiterverwendung Kompostierung MDF panels, cellulose insulaKompostierung Weiterverwendung Weiterverwertung tion, rubber granulate building Weiterverwertung Weiterverwertung protection matting, plate glass Energetische Energetische Verwertung Verwertung Weiterverwertung Herstellerrücknahme

Ge

Weiterverwertung Weiterverwertung Herstellerrücknahme

Herstellerrücknahme Verfüllung/„Landfill“ Composting Verfüllung/„Landfill“ Kompostierung Deponie Kl. New sheep’s Deponie Kl. 0 0 wool insulating Kompostierung matting, fibreboard, hemp wool Deponie Kl. Energetische Deponie Kl. II & & II IIVerwertung Energetic reclamation Energetische FacadeKl. wood&Verwertung shingles, black Deponie VI Deponie Kl. III III &decking, VI locust terrace cork Gefahrenstoff Gefahrenstoff floor tiles, new sheep’s wool Verfüllung/„Landfill“ Verfüllung/„Landfill“ insulating matting, plant-based Deponie Kl. Deponie Kl. 0 0 membrane, natural roof sealing rubber elastomer underlay, Deponie Kl. II solid spruce adheDeponie Kl. II & &formwork, II sive tape Deponie Kl. Kl. III III & & VI VI Deponie Gefahrenstoff Verfüllung/„Landfill“ Landfill class 0 / Fill Gefahrenstoff Deponie Kl. 0 Verfüllung/„Landfill“ Verfüllung/„Landfill“ Deponie Kl.Kl. 00 Deponie Verfüllung/„Landfill“ Deponie Kl. Kl. 0I & II Deponie Landfill classes I and II

Deponie Kl.Kl. I &I & II II Deponie Deponie Kl. III & VI Deponie Kl. I & II Gefahrenstoff Deponie Kl.Kl. III III && VI VI Deponie

Gefahrenstoff Gefahrenstoff Deponie Kl. IIIIII&and VI IV / Landfill classes Gefahrenstoff ­Hazardous materials

Manufacturer take-back

Herstellerrücknahme Herstellerrücknahme New sheep’s wool insulating Herstellerrücknahme matting, hemp wool, rubber Kompostierung granulate building protection Kompostierung Kompostierung matting Kompostierung Energetische Verwertung ForEnergetische a detailed illustration of loop potential see p. 156f. Energetische Verwertung Verwertung

Energetische Verwertung

155

Materials and masses Roof 30/50 + 40/90 mm-black locust terrace decking 100/55/4.1-mm steel profiles 3 mm roof sealing sheeting 180 + 70 –140-mm fibreboard insulation 0.05 mm aluminium vapour-proofing sheet 15-mm OSB /3 panels 120/260-mm spruce glued laminated timber 40/60-mm spruce battens 25-mm loam structural panels Flax mesh 3-mm loam plaster

Materials – percentages by mass

25.3 6.6 3.7 40.0 0.1 9.3 23.7 1.7 17.5 0.1 5.4 133.4

Exterior walls 20-mm larch shingles 2≈ 40/60 + 60/60-mm spruce battens 60 + 160-mm cellulose cavity insulation 80/160-mm KVH structural timber framework 5, 8 and 15-mm fibreboard panels 24 + 40/60-mm squared timber facing 25-mm loam structural panels Flax mesh 3-mm loam plaster

Plastics / Scrap synthetic metal blends

[kg/m2]

[kg/m2]

A2 timber

91.7

€ 1.00 Soil /loam

5.0 % 4.0 % 2.8 % 13.1 % 6.9 %

- € 1.00

18.9 %

- € 3.00 30.0 % Biological fibrous materials

17.8 % 1.3 %

A1 timber

- € 4.00

A2 timber

Soil /loam

5.9 %

Floors 10.5-mm cork tiles 30/60 + 40/60-mm spruce battens 60-mm fibreboard insulation 2-mm cork underlay 30-mm silver fir solid wood panels 140/280-mm glued laminated timber beams 100-mm sheep’s wool cavity insulation 25-mm loam structural panels Flax mesh 3-mm loam plaster

[kg/m ] 8.0 3.1 9.2 0.4 13.7 29.8 6.6 17.5 0.1 5.4 93.8

Ground slab / Foundation 10.5-mm cork tiles 30/60-mm spruce floor sleepers 60-mm fibreboard insulation 2-mm cork underlay 8-mm fibreboard 30-mm silver fir solid wood panels 140/200-mm glued laminated timber beams 200-mm cellulose cavity insulation 22-mm larch framework timber 70/70/7-mm galvanised steel L-profiles 1,600-mm galvanised ground screw footings

23.0 %

156

- €5.08 /m2

€ 1.00

- € 1.00 - € 2.00

0.1 % 14.4 %

15.3 % 10.0 %

A1 timber

Biological fibrous materials

2.6 % 9.6 %

- € 3.00 - € 4.00 - € 5.00 - € 6.00 - €3.70 /m2

Soil / loam

5.8 % 7.0 %

€ 1.00 € 0.00

3.3 %

- € 1.00

18.7 % 14.6 %

- € 2.00

0.1% - € 3.00

0.4 % Biological fibrous materials

9.8 %

- € 4.00

8.5 %

- € 5.00

31.9 %

A1 timber

A2 timber

- € 6.00

Scrap metal 11.9 %

3.3 %

A1 timber

1.4 % 14.1 %

€ 0.00 - € 1.00 - € 2.00

12.1 % 15.7 %

0.4 % Biological fibrous materials

- €3.33 /m2

€ 1.00

- € 3.00 - € 4.00

9.5 % 15.0 %

8.3 % 8.3 %

A2 timber

96.6

- € 6.00

19.1 %

[kg/m2] 8.0 1.3 9.2 0.4 8.0 13.7 15.2 11.7 14.5 11.5 3.1

- € 5.00

€ 0.00

Manufacturer take-back 2

€ 0.00

- € 2.00

13.2 9.2 14.0 8.8 21.1 2.4 17.5 0.1 5.4

Reclamation profits (+) and disposal costs (-) by dismantling process in €/m2

- € 5.00 - € 6.00 - €2.84 /m2

Rounding differences in the ­diagrams are software-related

Example 04

Global Warming Potential (GWP) in kg CO2eq /m2

Loop potential of the construction

Loop potential for the timber panel construction / larch and copper shingle facade example

400 300

46.1 %

1.7 %

200 100

+ -

0

17.4 % 76.3 %

-100 -200

*

*

3)

nts

4)

(B

3–

(C al

* waterproofing, loam structural panels and flax not included due to lack of data

100 80 60 40 20 0 -20 -40 -60 -80 -100

27.8 %

4.9 % 3.9 %

4)

) s itie (D bil ling a i l yc me os nd ec tur ce isp sa mr fac a t l i u D f o p n fr ne Re Ma Be 1–

A e(

Post-use

Pre-use

+ -

Pre-use

Post-use

Total

Closed-loop potential

78.0 %

68.4 %

146.4 %

Loop potential

78.0 %

100.0 %

178.0 %

14.0 %

22.0 %

22.5 %

Pre-use

Post-use 9.9 %

59.3 %

*

4)

) s itie (D bil ling a i l e d cyc os tur em an re isp fac ts om lac i u D f p n fr ne Re Ma Be 1–

A e(

3)

nts

4)

(B

3–

(C al

* loam structural panels and flax not included due to lack of data

28.8 % 16.9 %

Pre-use

Post-use

Total

Closed-loop potential

73.3 %

73.3 %

146.6 %

Loop potential

73.3 %

100.0 %

173.3 %

150 100 37.3 %

50

+ -

0

Pre-use

-50

)*

–3

tu

re

c ufa

n

Ma

1 (A

me

e

c pla

Re

4)

) s itie (D bil ng lia ycli d c o an re sp Di fits from e n Be

nts

4)

(B

3–

l (C

sa

40.6 %

2.4 % 9.1 %

75.3 %

-100

Post-use 10.6 %

Pre-use

Post-use

Total

Closed-loop potential

75.3 %

87.0 %

162.3 %

Loop potential

75.3 %

100.0 %

175.3 %

* sheep’s wool, loam structural panels and flax not included due to lack of data

160 140 120 100 80 60 40 20 0 -20 -40 -60 -80 -100

Loop potential key Pre-use Recycled materials (MRC, see B 2.4a p. 64) Regrown raw materials

16.4 % 22.5 %

+

Pre-Use

-

3)

4)

13.2 %

4)

) ies D ilit ng ( b i l a li e a d cyc tur os em an re fac ac isp s l t m u i D p f fro n ne Re Ma Be 1–

nts

(B

3–

l (C

30.0 %

Post-Use

71.6 %

A e(

From foundation to roof seal, the construction is characterised by the use of recyclable and primarily biotic materials. In the exterior wall with the larch shingles and in the roof construction, practically the only non-biotic primary ­resources are the loam materials. Thanks to their plasticity, however, these are easily ma­ terially reclaimable post-use. After dismantling, the structural timbers can be categorised as class 1 waste wood (A1 timber) and are therefore eligible for downcycling in the post-use portion of the loop potential, while the wea­ thered larch wood formwork is expected to be suitable for energetic reclamation only. The cellulose cavity insulation in the exterior wall and the ground plate is already the product of cascade utilisation. Its reusability at the end of the building’s lifetime, however, is in doubt, which is why it is categorised in the loop potential as a downcycled material. The recyclable roofing membrane is earmarked for energetic reclamation until a relevant manufacturer takeback system is introduced. While the natural building materials generate low to medium recovery costs, at the end of the building’s life cycle the steel elements of the foundation and the terrace construction still have a value as scrap metal, thanks to their practically limitless recycling potential. The ­dismantling effort required for the exterior wall and roof constructions is classified as low to very low. The ground screw dismantling effort is taken to be average. The timber and biological fibrous materials used bind carbon during their growth phase and thereby extract climate-damaging CO2 from the atmosphere. At the end of the usage period, energetic reclamation is assumed for all organic materials, as hardly any life cycle assessment data for scenarios involving ma­ terial recovery are currently available. Burning releases CO2, which is recorded in Module C of the life cycle assessment. The energy thus released, however, can replace energy produced from fossil fuels, resulting in a credit in Module D for the associated savings in CO2 generation.

11.7 %

22.0 %

Pre-Use

Post-Use

Total

Closed-loop potential

88.0 %

74.5 %

162.5 %

Loop potential

88.0 %

99.4 %

187.4 %

Post-use Reusable materials Recyclable materials Downcyclable materials from certifiably ­sustainable renewable sources Energetically recoverable materials from certifiably sustainable renewable sources Downcyclable materials Energetically recoverable materials from renewable sources

157

Example 05: Timber Panel Construction / Aluminium Honeycomb Composite Panel Facade Inexpensive urban mine

The outside and inside of the timber panel construction have contrasting appearances. Whereas the exterior features smooth, reflective aluminium panels with clearly delineated joints, the interior showcases visible ceiling beams, reused oak planks and sheep’s wool felt on the walls. On the outside, the ageing process of the shell material is not apparent; its expression is cool and disciplined. On the inside, the signs of wear and the patina of the reused timber elements, paired with the soft, open structure of the felt, create the impression of a cosy interior. The edges of the house are sharp, lacking both window ledges and parapet coping. The windows give the appearance of having been cut out of the facade. The frames of dark domestic thermally modified wood disappear behind the exterior cladding with its concealed window sill drainage detail. Seating furniture and shelves are placed in front of the upstairs wall openings; a frameless skylight completes the picture. Thanks to reversibly attached sealing and insulation sheets, the waterproof concrete of the cellar remains eligible for high-quality downcycling. The renewable resources and increasingly valuable metals incorporated in the assembled building components make this a perfect urban mining design. 158

Example 05

Partial elevation Scale 1:50 Vertical section Scale 1:20

Materials

Support structure and foundation • prefabricated timber panels •  prefabricated timber beam floors •  waterproof concrete tanking Exterior cladding • aluminium honeycomb composite panels • aluminium subconstruction Exterior floor coverings • extensive green roof Interior cladding •  felt from new sheep’s wool • loam construction panels with loam finishing coat Interior coverings •  solid oak planks •  floor sleeper subconstruction Insulation •  hemp insulation matting •  fibreboard insulation •  sheep’s wool insulating panels •  foam glass insulating panels •  foam glass insulating gravel •  bulk sea grass insulation Doors / Windows • thermally modified wood frames • triple glazing • flashings with lapped EPDM connecting foils and hemp oakum strips 159

a

Horizontal sections Scale 1:20 a  Ground floor section b  Upper floor section

Roof construction (U-value: 0.17 W/m2K)

Exterior wall construction (U-value: 0.15 W/m2K)

Entry door

• 40 – 200-mm extensive green roof, with 500-mm gravel bands at flashings • 100-mm system substrate growing medium of recycled crushed clay brick enriched with substrate compost, loosely poured • 3-mm biosynthetic filter sheet, loosely laid • 60-mm drainage layer of > 95 % sugarbased renewable resources and minerals, loosely laid • interspersed with bulk fill, 100 % recycled crushed clay brick • 3-mm biosynthetic protection and storage matting, loosely laid • 2-mm 100 % EPDM roof sealing membrane, sd: 140 m, uniformly bonded at overlapping seams, loosely laid • 240-mm 70 % recycled foam glass panel insulation, multiple layers, with additional 30 – 80-mm tapered insulation layer, λ: 0.038 W/mK, bonded together and loosely laid • 0.05-mm coarse-grained aluminium vapourproofing foil, sd: > 2500 m, loosely laid, mechanically fastened to parapet with ­aluminium profile • 15-mm untreated spruce formwork facing, planed, secured with screws • 100/240-mm untreated spruce roof beam, in concealed galvanised steel beam hanger

• 10-mm honeycomb composite panels, 100 % aluminium (E6EV1 anodised), secured with screws • aluminium profile subconstruction • 0.20-mm windproofing layer of sheep’s wool felt on kraft paper with biological adhesive, vapour-permeable, overlapped and stapled • 40/60-mm untreated spruce counter battens, secured with screws • 40/60-mm untreated spruce battens, secured with screws • interspersed with 80-mm lignin-bonded fibreboard insulation, double layer, λ: 0.04 W/mK • 15-mm untreated spruce formwork, secured with screws • 160/60-mm untreated spruce KVH solid ­timber framing • 160-mm bulk seagrass cavity insulation, λ: < 0.04 W/mK, factory-installed and ­compacted • 15-mm untreated spruce formwork, secured with screws • 0.2-mm low-density polyethylene (PE-LD) vapour barrier, sd: >100 m, overlapped and stapled • 40/24-mm untreated spruce battens, secured with screws • interspersed with 40-mm hemp fibre insulation matting with PLA reinforcing fibres, λ: 0.04 W/mK • 2-mm felt fabric lining, 100 % sheep’s wool, sound-absorbing, stretched around battens

• entry door flush with inner surface of wall, frame of thermally modified beech, leaf clad with 10-mm honeycomb composite panels, 100 % aluminium (E6EV1 anodised), secured with screws • between, 70-mm hemp fibre insulation ­matting with PLA reinforcing fibres, λ: 0.04 W/mK • windproof flashing with lapped EPDM ­connecting foils, joints packed with hemp oakum

Roof drip edge

• 10-mm honeycomb composite panels, 100 % aluminium (E6EV1 anodised), tilted and secured to tapered timber plank with screws

160

Windows (U-value: 0.70 W/m2K)

• 78-mm thermally modified beech wood frames in the insulation plane, triple glazing • windproof flashing with lapped EPDM connecting foils, joints packed with hemp oakum • 20-mm impact-rated laminated safety glass, secured with frame-integrated retaining strip

Interior wall construction

• 20-mm loam structural panels with loam ­plaster and loam mortar, flax reinforcing mesh, Q3 surface finish, secured with screws • 40/24-mm untreated spruce battens as ­interior facing, secured with screws • interspersed with 40-mm hemp fibre insulation matting with PLA reinforcing fibres, λ: 0.04 W/mK • 15-mm untreated spruce formwork, secured with screws • 100/60-mm untreated spruce KVH solid ­timber framing • 100-mm bulk sheep’s wool cavity insulation matting, λ: 0.04 W/mK, factory-installed • 15-mm untreated spruce formwork, secured with screws • 40/24-mm untreated spruce battens, secured with screws • interspersed with 40-mm hemp fibre insulation matting with PLA reinforcing fibres, λ: < 0.04 W/mK • 2-mm felt fabric lining, 100 % sheep’s wool, sound-absorbing, stretched around battens

Example 05

  Loop Potential of the Construction Materials: Recycling Path / End-of-Life Potential

Verfüll Depon Verfüll Depon Depon

Reuse

Wiederverwendung Recycled crushed clay brick, Wiederverwendung foam glass gravel insulating fill Wiederverwertung

Recycling

b

Wiederverwertung aluminium honeycomb composite Wiederverwendung Wiederverwendung Weiterverwendung panels, aluminium vapour-proofing, loam structural panels, foam Weiterverwendung Wiederverwertung glass gravel insulating fill Wiederverwertung Weiterverwertung

Depon Verfüll Verfüll Depon Depon Depon Gefahr Depon Gefahr Depon Depon

Further use Weiterverwertung

Depon Depon Gefahr Gefahr

Weiterverwendung Weiterverwendung Herstellerrücknahme

Herstellerrücknahme Downcycling Weiterverwertung

Floor construction

Ground slab construction (U-value: 0.13 W/m2K)

• 20-mm oiled oak planks, reused, tongue-andgroove joining with concealed screws • 60/80-mm untreated spruce floor sleepers, installed floating on impact sound insulation strips of 100 % hemp fibre felt • interspersed with 40 mm hemp fibre impact sound insulation matting with PLA reinforcing fibres, λ: < 0.04 W/mK, loosely laid • on 40-mm bed of crushed recycled clay brick fill • 0.25-mm kraft paper trickle protection, ­overlapped and loosely laid • 20-mm edge insulation strip, 100 % hemp wool • 15-mm untreated spruce formwork facing, planed, secured with screws • 100/200-mm untreated spruce KVH ceiling beam, on a natural rubber elastomer sheet, attached with screws to concealed galvanised steel beam hanger; on the ground floor, fastened to KVH of wood use class 3.2 (DIN 68 800-1), durability class DC 2 (DIN EN 359-2), e.g. oak

• 20-mm oiled oak planks, reused, tongue-andgroove joining with concealed screws • 60/40-mm untreated spruce battens, secured with screws • interspersed with 40-mm hemp fibre impact sound insulation matting with PLA reinforcing fibres, λ: < 0.04 W/mK, loosely laid • 60-mm lignin-bonded fibreboard impact sound insulation, double layer, λ: < 0.04 W/mK, loosely laid • 20-mm edge insulation strip, 100 % hemp wool • 0.05-mm coarse-grained aluminium vapourproofing foil, sd: > 2,500 m, loosely laid and run up the walls to the skirting plate • 250-mm waterproof concrete ground plate containing recycled concrete aggregate, with waterstop • 5-mm geotextile fabric separating sheet, 100 % polypropylene, loosely laid • 360-mm foam glass gravel insulating fill, 98 % waste glass, λ: 0.08 W/mK, loosely poured, with drainage pipes • 5-mm geotextile fabric separating sheet, 100 % polypropylene, loosely laid

Cellar wall construction (U-value: 0.17 W/m2K)

• 300-mm waterproof concrete wall containing recycled concrete aggregate, with ­waterstop • 450-mm foam glass gravel insulating fill, 98 % waste glass, λ: 0.08 W/mK • in 5-mm geotextile fabric wall bag, 100 % polypropylene (PP), mechanically fastened to waterproof concrete

Wiederverwendung Wiederverwendung

Wiederverwertung Wiederverwendung Wiederverwertung

Weiterverwendung Wiederverwertung Weiterverwendung

Weiterverwertung Weiterverwendung Weiterverwertung

Weiterverwertung Spruce KVH, solid spruce formKompostierung work, reused oak planks, tapered Kompostierung Wiederverwendung Herstellerrücknahme timber board, spruce battens Herstellerrücknahme Energetische Verwertung and floor sleepers, thermally ­m odified beech, EPDM roof Energetische Verwertung Wiederverwertung Kompostierung Kompostierung ­sWiederverwendung ealing membrane, low-density polyethylene (PE-LD) vapour ­bWeiterverwendung arrier, polypropylene (PP) geo­ Energetische Verwertung Energetische Verwertung Wiederverwertung textile ­fabric, waterproof concrete, plate glass, foam glass insulating Weiterverwertung panels, sheep’s wool felt Weiterverwendung Wiederverwendung

Verfüll Depon

Depon Verfüll Depon Depon Gefahr Depon

Depon Verfüll Gefahr Depon

Manufacturer take-back

Herstellerrücknahme Hemp insulating matting, bulk Weiterverwertung Wiederverwertung ­seagrass insulation, sheep’s wool insulating matting, hemp wool, Kompostierung Herstellerrücknahme Weiterverwendung EPDM roof sealing membrane

Depon

Depon Gefahr

Energetische Verwertung Composting

Kompostierung Weiterverwertung Sheep’s wool insulating matting, fibreboard insulation, hemp insu­ lating matting, hemp felt impact Energetische Verwertung Herstellerrücknahme sound insulation matting, hemp oakum strips, extensive green roof Kompostierung vegetation, system substrate Energetic reclamation

Energetische Verwertung Bulk seagrass insulation, sheep’s wool felt on kraft paper, kraft paper trickle protection, drainage element, filter sheet and storage protection matting, natural rubber ­elastomer sheeting Verfüllung/„Landfill“ Landfill class 0 / Fill

Deponie Kl. 0 Verfüllung/„Landfill“ Deponie Kl. 0 Verfüllung/„Landfill“ Deponie Kl. I & II Deponie Kl. 0 Landfill classes I and II Deponie Kl. I & II Deponie Kl. III & VI Deponie Kl. I & II Gefahrenstoff Deponie Kl. III & VI Gefahrenstoff Landfill classes III & and Deponie Kl. III VIIV / materials Hazardous Gefahrenstoff

Herstellerrücknahme Weiterverwertung Herstellerrücknahme

Kompostierung Herstellerrücknahme Kompostierung

Energetische Verwertung Kompostierung

161

Example 06: Timber Panel Construction / Charred Timber Formwork Facade Reused and of further use: Wood for carbon storage

At first glance the house’s shape is familiar – two storeys, with a gable roof, a balcony and a terrace. On closer inspection, however, the timber building surprises with its construction methods and its unusual use of materials. The load-bearing system of walls and floors comprises diagonally placed solid spruce structural timbers, which are finished with compression-resistant wood fibre insulation shims to form prefabricated elements. Rear-ventilated larch boards lend the roof and wall exteriors a unifying charred black, silken gloss with a finely textured surface. This is made possible through the use of concealed trapezoidal sheet panels on the roof, which serve as the water-bearing layer. Although the charring of the timber improves its durability, its suitability as an exterior wall cladding must nevertheless be certified. The roof and balcony drainage details are hidden from view, thus supporting the abstract quality of the building’s appearance. The concept is extended to the balcony exit, which has no step and forms a continuous extension of the first storey floor. The interior features another classic material: ceramic tiles as an exposed screed. These are complemented by large reused solid timber panels which serve as wall and ceiling cladding. 162

Example 06

Partial elevation Scale 1:50 Vertical section Scale 1:20

Materials

Support structure and foundation • prefabricated timber framework system of KVH solid structural timbers •  ground screw footings Exterior cladding •  charred larch wood formwork • battens Exterior floor coverings •  charred larch terrace decking • tile-levelling spindles Interior cladding •  solid timber panels • battens Interior floor coverings •  ceramic tile dry screed, floating •  underfloor heating system panels Insulation •  bulk wood shavings insulating fill •  fibreboard insulating panels Doors / Windows •  untreated oak door frame • glued laminated timber post-and-beam, capped with aluminium • triple glazing • flashings with lapped EPDM connecting foils and hemp wool 163

Horizontal sections Scale 1:20 a  Ground floor section b  Upper floor section

a Roof construction (U-value: 0.16 W/m2K)

Exterior wall construction (U-value: 0.20 W/m2K)

Entry door

• 24-mm larch board formwork, surface charred, secured with screws • 24/48-mm dark thermally modified wood ­battens, rear-ventilated, secured with screws • 35/207-mm galvanised steel trapezoidal sheet in negative position as water-bearing layer, powder-coated black, overlapped and secured with screws • 24/48-mm untreated spruce battens to ­establish ventilation plane, secured with screws • 0.2-mm high-density polyethylene (PE-HD) windproofing, vapour-permeable, sd: > 0.025 m, loosely laid • 100-mm lignin-bonded fibreboard insulation, multiple layers, λ: 0.04 W/mK, secured with wood screws • 20-mm untreated spruce formwork, tongueand-groove joints, secured with screws • 100/180-mm untreated spruce rafters, secured with screws • 180-mm bulk wood shavings cavity ­insulation, shavings from spruce and fir, λ: 0.049 W/mK, blown in • 20-mm untreated spruce formwork, tongueand-groove joints, secured with screws • 0.2-mm low-density polyethylene (PE-LD) vapour barrier, sd: >100 m, overlapped and stapled • 28/48-mm untreated spruce battens as ­interior facing, secured with screws • 19-mm reused large solid oak panels, oiled and grooved, secured with concealed screws

• 24-mm larch board formwork, surface charred, secured with screws • 24/48-mm dark, thermally modified wood ­battens, rear-ventilated, secured with screws • 24/28-mm dark, thermally modified wood counter battens, rear-ventilated, secured with screws • 0.2-mm high-density polyethylene (PE-HD) windproofing, black, vapour-permeable, sd: 0.025 m, loosely laid • 40/60-mm untreated spruce battens, secured with screws • interspersed with 60-mm lignin-bonded ­fibreboard insulation, double layer, λ: 0.04 W/mK • 200-mm system composed of diagonally placed KVH spruce timbers (240/60-mm) with compression-resistant wood fibre ­insulation shims (λ: 0.04 W/mK) and faced with 20-mm tongue-and-groove untreated spruce panels, prefabricated • 0.2-mm low-density polyethylene (PE-LD) vapour barrier, sd: > 100 m, overlapped and stapled • 28/48-mm untreated spruce battens as ­interior facing, secured with screws • 19-mm reused large solid oak panels, oiled and grooved, secured with screws

• 100-mm door flush-mounted to wall exterior; oak frame, insulated leaf with aluminium cladding (E6/C35 dark-anodised) and recessed grip on outside, oiled solid timber panel cladding on inside • 55-mm 100 % cork insulating panel inside leaf, λ: 0.037 W/mK, windproof flashing with lapped EPDM connecting foils

Roof drip edge

• 150-mm sheet steel box gutter, powdercoated black 164

Window post-and-beam (U-value: 0.69 W/m2K)

• 60/150-mm post-and-beam construction, untreated glued laminated timber with aluminium capping strip (E6/C35 ­dark-anodised), flush-mounted to wall ­exterior; ­triple glazing, windproof flashing with lapped EPDM connecting foils

Terrace door (U-value: 0.69 W/m2K)

• 80-mm terrace door flush-mounted to wall interior, oak frame, triple glazing, windproof flashing with bulk jute wool Interior wall construction

• 19-mm reused large solid oak panels, oiled and grooved, secured with screws • 28/48-mm untreated spruce battens as ­interior facing, secured with screws • 20-mm untreated spruce formwork, tongueand-groove joints, secured with screws • 100/100-mm untreated spruce KVH structural timber frame secured with screws • interspersed with 100-mm insulation of bulk wood shavings from untreated spruce and fir,  λ: 0.049 W/mK, factory-installed and compacted • 20-mm untreated spruce formwork, tongueand-groove joints, secured with screws • 28/48-mm untreated spruce battens as ­interior facing, secured with screws • 19-mm reused large solid oak panels, oiled and grooved, secured with screws Floor constructions

• 20-mm ceramic tile dry screed, reddishbrown, floating • 30-mm fibreboard insulation floor heating panels with aluminium thermal conducting

Example 06

Loop Potential of the Construction Materials: Recycling Path / End-of-Life Potential

Verfüll Depon Verfüll

Reuse

Wiederverwendung Wiederverwendung

Depon Depon

Wiederverwertung

Recycling

Wiederverwertung Ground screw foundation, trape­z­ Weiterverwendung oidal sheet, steel levelling spindles, steel box gutter, aluminium capWeiterverwendung ping strip from the post-and-beam Wiederverwendung Wiederverwendung Weiterverwertung construction, aluminium underfloor Weiterverwertung heating system panels, stainless Wiederverwertung steel facade drain Wiederverwertung Herstellerrücknahme

Depon Depon Gefahr Depon

Herstellerrücknahme Further use

Depon Depon Gefahr Gefahr

Weiterverwendung Weiterverwendung Kompostierung

Kompostierung Weiterverwertung Energetische Verwertung Spruce KVH, solid timber diagonalboard panel, reused solid oak Energetische Verwertung Herstellerrücknahme ­pHerstellerrücknahme anels, battens, wooden wedges, thermally modified wood battens, glued laminated timber post-andKompostierung Wiederverwendung Kompostierung beams, oak door frame, tongueand-groove timber panels, floor heating pipe alloy, low-density Energetische Verwertung Wiederverwertung Energetische Verwertung ­pWiederverwendung olyethylene (PE-LD) vapour barrier, EPDM roof sealing membrane, EPDM connecting foils, rubber Weiterverwendung Wiederverwendung Wiederverwertung granulate building protection matting, plate glass, dry screed tiles Weiterverwertung Wiederverwertung Weiterverwendung

Verfüll Gefahr Verfüll Depon Depon

Depon Depon

Downcycling Weiterverwertung b

sheet and PE-RT /aluminium alloy floor ­heating pipes, floating • 30-mm lignin-bonded fibreboard impact sound insulation, λ: 0.04 W/mK, floating • 30-mm solid silver fir timber diagonal-board panela, individual boards connected with one another via dovetail joints, secured with screws • 200-mm system composed of diagonally placed KVH spruce timbers (240/60 mm) with compression-resistant wood fibre insulation shims (λ: 0.04 W/mK) and faced with 20-mm tongue-and-groove-jointed untreated spruce panels, prefabricated • 50/70-mm untreated spruce structural timber, secured with screws • 40/60-mm untreated spruce battens, secured with screws • 19-mm reused large solid oak panels, oiled and grooved, secured with screws Ground floor construction (U-value: 0.18 W/m2K)

• 20-mm ceramic tile dry screed, floating • 30-mm underfloor heating system insulating panels of lignin-bonded fibreboard, λ: 0.04 W/mK, with aluminium thermal conducting sheet and PE-RT /aluminium alloy floor heating pipes, floating • 30-mm lignin-bonded fibreboard impact sound insulation, λ: 0.04 W/mK, floating • 30-mm solid silver fir timber diagonal-board panels, individual boards connected with one another via dovetail joints, secured with screws • 180/250-mm untreated spruce KVH ceiling beam, secured with screws • interspersed with 250-mm insulation of bulk wood shavings from untreated spruce and fir,  λ: 0.049 W/mK, factory-installed and compacted

• 22-mm timber formwork, wood use class 2 (DIN 68 800-1), durability class 2 (DIN EN 35), e.g. European larch, pine / Scots pine, oak, sd: 0.88 m, tongue-andgroove jointed, secured with screws • galvanised steel ground screw footings, screwed into the ground Balcony floor construction

• 24-mm larch board formwork, surface charred, secured with screws • 40/60-mm dark, thermally modified wood floor sleepers, rear-ventilated, secured with screws • 80-mm galvanised steel levelling spindles, secured with screws • 10-mm building protection matting, polyur­ ethane-bonded recycled rubber granulate, spot-placed under levelling spindles • stainless steel facade drain, aluminium cover grating (E6/C35 dark-anodised) • 2-mm 100 % EPDM roof sealing membrane, sd: 140 m, uniformly bonded at overlapping seams, loosely laid • 20-mm untreated spruce formwork, tongueand-groove joints, secured with screws • 30-mm untreated spruce wedge, 2 % incline, secured with screws • 20-mm untreated spruce formwork, tongueand-groove joints, secured with screws spruce KVH ceiling • 50/180-mm untreated Wiederverwendung Wiederverwendung Wiederverwendung beam, secured with screws • 40/60-mm thermally modified wood battens, Wiederverwertung rear-ventilated, secured with screws Wiederverwertung Wiederverwertung • 24-mm larch board formwork, surface charred, secured with screws Weiterverwendung Weiterverwendung Weiterverwendung

Manufacturer take-back

Kompostierung Kompostierung Kompostierung

Depon Verfüll Depon Depon Verfüll Gefahr Depon

Depon Depon Gefahr

Depon Gefahr

Herstellerrücknahme Weiterverwendung EPDM roof sealing membrane, Weiterverwertung ­rubber granulate building protection matting Kompostierung Weiterverwertung Herstellerrücknahme Energetische Verwertung Composting Herstellerrücknahme

Kompostierung Fibreboard insulation, bulk wood shavings insulating fill, jute wool Kompostierung Energetische Verwertung Energetic reclamation

Energetische Verwertung Charred larch board formwork, high-density polyethylene (PE-HD) windproofing, solid spruce formwork Landfill class 0 / Fill Verfüllung/„Landfill“ Verfüllung/„Landfill“

Verfüllung/„Landfill“ Deponie Kl. Deponie Kl. Kl. 00 0 Deponie

Landfill classes Deponie Kl. I I&and II II

Deponie Kl. Kl. II & & II II Deponie

Deponie Kl. III & VI

Deponie Kl. III III &and VI IV / Landfill classes III& Deponie Kl. VI Gefahrenstoff Gefahrenstoff Hazardous materials Gefahrenstoff

Weiterverwertung Weiterverwertung Weiterverwertung Herstellerrücknahme Herstellerrücknahme Herstellerrücknahme

Verfüll Depon

165

Example 07: Solid Timber Construction / Dry-Laid Clay Brick Facade Sufficient solid timber construction – mortarless facing shell

The entire house is built from solid timber, with ceilings of stacked board and the walls consisting of a system of vertically interlocking form-milled timber slats that perfectly support loads at right angles to their grain. In line with the concept of sufficiency, the wood surfaces in the interior remain visible; surface cladding is unnecessary. The light-coloured clay brick facade is composed of special, long-format bricks laid in a mortar-free and easily dismantled dry-joining system. The inner facing of the window frames is timber, while the casements outside immediately in front of them consist of cognac-coloured anodised aluminium. On the interior, the frame is covered by a deep, picture-frame-like timber reveal. The construction of the cellar is extremely innovative: the solid wood support structure is protected on its exterior by an adhesivefree multilayered rear-ventilated waterproofing system which is mechanically fastened to it at plinth height. This system, used for years in the waterproofing of landfills, is used here in an architectural application. Recycled foam glass gravel serves as cellar insulation, both compacted and load-distributing under the ground slab and in geotextile bags loosely positioned in front of the walls. 166

Example 07

Partial elevation Scale 1:50 Vertical section Scale 1:20

Materials

Support structure and foundation •  solid timber wall elements •  stacked board ceiling •  solid timber basement Exterior cladding •  clay bricks, dry-laid •  rear-anchored to OSB panels Exterior floor coverings •  extensive green roof Interior cladding •  exposed solid timber wall facing Interior floor coverings •  solid oak planks •  floor sleeper subconstruction •  linoleum panels •  floor sleeper subconstruction Insulation •  bulrush insulating panels •  reed insulating matting •  fibreboard insulation •  foam glass insulating gravel Doors / Windows •  wood-aluminium frames •  triple glazing •  flashing packed with bulk hemp wool 167

a

Roof construction (U-value: 0.17 W/m2K)

• 40 – 200-mm extensive green roof, with 500-mm recycled crushed ceramic tile at building component joints • 30-mm growing medium, sedum substrate over jute underlayer, loosely laid • 30-mm substrate of perforated rock wool felt, no additional bonding agents, loosely laid • 12.5-mm recycled, impact-resistant polystyrene (HIPS) drainage element on a geotextile base, loosely laid • 1.8-mm waterproof polyolefin (FPO) root ­barrier, PVC- and biocide-free, loosely laid and welded at overlaps and mechanically fastened to the parapet • 240-mm bulrush panel insulation, multiple layers with additional 60 –120-mm tapered layer, λ: 0.052 W/mK, loosely laid • 0.2-mm low-density polyethylene (PE-LD) vapour barrier, sd: >100 m, overlapped and stapled • 200-mm untreated spruce stacked board ceiling, exposed, λ: 0.13 W/mK, mechanic­ ally fastened to cork separating sheeting with beech wood dowels

Horizontal sections Scale 1:20 a  Ground floor section b  Upper floor section

• 100-mm multilayered bulrush insulating ­matting, additive-free, rot-resistant, λ: 0.045 W/mK, packed in • 100/50-mm untreated spruce structural ­timber, secured with screws • 220-mm solid timber wall of vertically ­interlocking form-milled spruce slats, untreated, fastened at sills with wooden ­dowels • 40-mm untreated solid spruce shelves, secured with screws • aluminium loggia balustrade (E6/C33 ­anodised), secured with screws Windows (U-value: 0.82 W/m2K)

• wood-aluminium frame, mounted flush to the exterior, untreated softwood frame sash, aluminium casement (E6/C33 anodised) with thermal separation, triple glazing, windproof flashing packed with hemp wool • 0.7-mm aluminium sill and soffit (E6/C33 ­anodised), secured with screws Loggia door (U-value: 0.82 W/m2K)

• 2-mm flat roof edge profiles, anthracite powder-coated aluminium, multi-piece, tilted and secured with screws

• loggia door mounted flush to the exterior, untreated softwood jamb as anchor plate, aluminium casement (E6/C33 anodised) with thermal separation, triple glazing, bolted to structural timber with window frame anchors • windproof flashing packed with hemp wool

Exterior wall construction (U-value: 0.20 W/m2K)

Interior wall construction

• clay bricks in a special d = 100 mm dry-joining system format, fastened to one another via steel clips, with a bolted stainless steel rear anchor • 16-mm OSB/3 panels with formaldehyde-free bonding agents, secured with screws

• 22-mm untreated spruce formwork, tongueand-groove joints, secured with screws • 28/48-mm untreated spruce battens, secured with screws • 5-mm fibreboard, 97 % wood, secured with screws

Roof drip edge

168

• 100/100-mm untreated spruce KVH solid ­timber framing • interspersed with hemp fibre insulating ­matting with PLA fibre reinforcement • 5-mm fibreboard, 97 % wood, secured with screws • 28/48-mm untreated spruce battens, secured with screws • 22-mm untreated spruce formwork, tongueand-groove joints, secured with screws Floor constructions

• 9.8-mm click-lock linoleum tiles: HDF support panels, linoleum overlay, cork counterlayer, secured with screws • 60/40-mm untreated spruce battens, secured with screws • interspersed with 40-mm lignin-bonded ­fibreboard impact sound insulation, λ: 0.04 W/mK, loosely laid • 40-mm bed of recycled crushed clay brick fill • 200-mm untreated spruce stacked board ceiling, exposed, λ: 0.13 W/mK, mechanic­ ally fastened to cork separating sheet with beech wood dowels Loggia floor construction (U-value: 0.17 W/m2K)

• 27-mm untreated oak planks, secured with screws • 35 – 70/60-mm untreated oak tapered planks • 10-mm building protection matting, polyur­ ethane-bonded recycled rubber granulate, loosely laid • 1.8-mm waterproof polyolefin (FPO) root ­barrier, PVC- and biocide-free, loosely laid, welded at overlaps and mechanically fastened to the parapet

Example 07

Loop Potential of the Construction Materials: Recycling Path / End-of-Life Potential

Verfüll Depon

Reuse

Wiederverwendung Oak planks, clay bricks, recycled crushed clay brick, foam glass gravel insulating fill (cellar wall) Wiederverwertung Wiederverwendung

Depon Verfüll Depon Depon Gefahr Depon

Weiterverwendung Recycling

Wiederverwertung Aluminium flat roof drip edge ­pWiederverwendung rofiles, aluminium balustrade, Wiederverwendung ­aWeiterverwertung luminium window casements, Weiterverwendung foam glass gravel insulating fill Wiederverwertung (ground slab) Wiederverwertung Herstellerrücknahme Weiterverwertung

Verfüll Verfüll Depon Depon Gefahr

Depon Depon

Depon Depon Gefahr Gefahr

Further use

Weiterverwendung Weiterverwendung Kompostierung Herstellerrücknahme

Downcycling Weiterverwertung

b

• 200-mm bulrush insulating panel, multiple layers, λ: 0.052 W/mK, loosely laid • 0.2-mm low density polyethylene (PE-LD) vapour barrier, sd: > 100 m, overlapped and stapled • 22-mm OSB/3 panels with formaldehyde-free bonding agents, secured with screws • 15 – 40/60-mm untreated spruce tapered plank, secured with screws • interspersed with 40-mm bulk fill of recycled crushed clay brick • 200-mm untreated spruce stacked board ceiling, exposed, λ: 0.13 W/mK, mechanic­ ally fastened to cork separating sheet with beech wood dowels Cellar wall construction (U-value: 0.16 W/m2K)

• 450-mm foam glass gravel insulating fill, 98 % waste glass, λ: 0.10 W/mK • in 5-mm storey-high geotextile fabric wall bags, 100 % polypropylene (PP), loosely placed • 2-mm high-density polyethylene (PE-HD) waterproofing membrane, loosely laid and clamped with a fastening rail • 9-mm high-density polyethylene (PE-HD) drainage core with upper layer of separating and filtering fleece, loosely laid • 440-mm solid timber wall of vertically ­interlockeing form-milled spruce slats, untreated, fastened at sills with wooden ­dowels Note: To prevent moisture damage in the ­cellar construction described here, relative humidity of more than 50 % is to be avoided. For uses that are likely to be exposed to ­moisture, mechanical ventilation must be ­provided.

Ground floor construction (U-value: 0.15 W/m2K)

• 27-mm untreated oak planks, secured with screws • 60/40-mm untreated spruce battens, secured with screws • interspersed with 40-mm lignin-bonded ­fibreboard impact sound insulation, λ: 0.04 W/mK, loosely laid • 200-mm untreated spruce stacked board ceiling, exposed, λ: 0.13 W/mK, mechanic­ ally fastened to cork separating sheeting with beech wood dowels • 9-mm high-density polyethylene (PE-HD) drainage core with upper layer of separating and filtering fleece, loosely laid • 2-mm high-density polyethylene (PE-HD) waterproofing membrane, loosely laid and clamped with a fastening rail • 5-mm geotextile fabric separating sheeting, 100 % polypropylene, loosely laid • 400-mm foam glass gravel insulating fill, 98 % waste glass, λ: 0.1 W/mK, loosely poured and compacted • 5-mm geotextile fabric separating sheeting, 100 % polypropylene, loosely laid Wiederverwendung Wiederverwendung Wiederverwendung

Weiterverwertung Energetische Verwertung Spruce KVH, solid spruce boards, Kompostierung Wiederverwendung spruce battens and floor sleepers, Herstellerrücknahme softwood window frame sash, Herstellerrücknahme OSB/3 panels, Verwertung cork separating Energetische Wiederverwendung Wiederverwertung sheeting, polyolefin and low-density Kompostierung Kompostierung polyethylene ((PE-LD) roof sealWiederverwertung ing membranes, polypropylene Weiterverwendung geotextile fabric, rubber granulate Energetische Verwertung Verwertung Energetische building protection matting, plate Weiterverwendung Weiterverwertung glass Wiederverwendung Manufacturer take-back Weiterverwertung

Herstellerrücknahme Hemp wool, polyolefin roof sealing Wiederverwertung membrane, rubber granulate buildHerstellerrücknahme ing protection matting Kompostierung Weiterverwendung Composting

Kompostierung Energetische Reed insulatingVerwertung matting, bulrush, Weiterverwertung insulating panels, fibreboard insu­ lation, hemp wool, hemp fibre Energetische Verwertung ­iHerstellerrücknahme nsulating matting, extensive green roof vegetation, system substrate growth medium, rock wool felt Kompostierung Energetic reclamation

Energetische Verwertung Linoleum floor tiles, drainage ­element Landfill class 0 / Fill Verfüllung/„Landfill“ Verfüllung/„Landfill“

Verfüllung/„Landfill“ Deponie Kl. Deponie Kl. Kl. 00 0 Deponie

Wiederverwertung Wiederverwertung Wiederverwertung

Landfill classes Deponie Kl. I I&and II II

Weiterverwendung Weiterverwendung Weiterverwendung

Deponie Kl. III III &and VI IV / ­ Landfill classes III& Deponie Kl. VI Gefahrenstoff Gefahrenstoff Gefahrenstoff Hazardous materials

Weiterverwertung Weiterverwertung Weiterverwertung Herstellerrücknahme Herstellerrücknahme Herstellerrücknahme

Deponie Kl. Kl. II & & II II Deponie

Deponie Kl. III & VI

For a detailed illustration of loop potential see p. 170f.

Kompostierung Kompostierung Kompostierung Energetische Verwertung Verwertung Energetische Energetische Verwertung

169

Verfüll Depon

Verfüll Depon

Depon Depon Gefahr

Depon Verfüll Gefahr Depon

Depon

Depon Gefahr

Materials and masses Roof 30-mm sedum vegetation matting 30-mm rock wool felt 12.5-mm HIPS drainage element 1.8-mm FPO waterproofing 240 + 60 – 20-mm bulrush (typha) insulating panels 0.2-mm PE-LD vapour barrier 200-mm spruce stacked board floor

Materials – percentages by mass

Reclamation profits (+) and disposal costs (-) by dismantling process in €/m2

Synthetics

[kg/m2] 25.0 3.3 1.4 1.9 72.6

0.7 %

€0.00 1.0 %

A1 timber

- €4.00

36.2 % 48.0 %

51,3%

0.2 96.4

- €5.00 - €6.00 - €7.00

1.6 %

- €8.00

1,4%

Biological fibrous materials

- €9.00

12.5 %

- €10.00 - €9.11/m2

Biological fibrous materials

€ 0.00

A2 timber

90-mm dry-laid bricks Stainless steel fasteners 16-mm OSB/3 panels 100/50-mm structural timber 100-mm reed insulation 220-mm solid spruce walls

- €2.00 - €3.00

200.8

Exterior walls

- €1.00

[kg/m2]

5.3 % 3.6 %

142.1 0.1 9.9 4.0 14.8 106.0

Bricks

1.4 %

- € 1.00 - € 2.00 - € 3.00 - € 4.00 - € 5.00

51.3 %

51,3%

- € 6.00 - € 7.00

38.3 %

276.9

- € 8.00

1,4%

A1 timber

- € 9.00 - €10.00 - €5.56 /m2 Biological fibrous materials

Floors 9.8-mm linoleum tiles 60/40-mm spruce floor sleepers 40-mm fibreboard insulation 40-mm recycled crushed clay brick 200-mm stacked board ceiling

[kg/m2] 8.6 2.3 5.6 39.0 96.4

€0.00 A1 timber

3.7 %

Bricks

- €1.00 - €2.00 - €3.00

25.7 %

- €4.00 - €5.00 - €6.00

151.9

63.4 %

5.7 % A2 timber

- €7.00 - €8.00

1.5 %

- €9.00 - €10.00 - €4.64 /m2

Synthetics

Ground slab / Foundation 27-mm oak planks 60/40-mm spruce floor sleepers 40-mm wood fibre insulation 200-mm spruce stacked board flooring 2-mm PE-HD waterproofing + 9-mm PE-HD drainage core 2≈ 5-mm PP geo-fleece 400-mm foam glass gravel insulating fill

[kg/m ] 2

Manufacturer take-back

19.4 2.9 5.4 96.4 2.7

28.9 %

0.8 52.0

3.0 %

0.4 %

€0.00 A1 timber

1.5 %

- €1.00 - €2.00 - €3.00 - €4.00

53.7 %

- €5.00 - €6.00

179.7

Biological fibrous materials

Reuse

- €7.00 - €8.00

10.8 % 1.6 %

- €9.00 - €10.00 - €7.13 /m2

Rounding differences in the ­diagrams are software-related

170

Example 07

Global Warming Potential (GWP) in kg CO2eq /m2 250 200 150 100 50 0 -50 -100 -150 -200

Loop potential for the solid timber construction / dry-laid clay brick facade in the example

30.1 %

+

-

)

–3

A1

( re

ctu

ufa

n Ma

Loop potential of the construction

ce

pla

Re

1)

(B

3–

(C al

Straw used in place of reed insulating panels

250 200 150 100 50 0 -50 -100 -150 -200

96.6 %

Post-use 7.2 % 0.6 % 9.1 %

38.9 %

4)

) ies D ilit g ( iab yclin l d c os an re sp Di fits from e n Be

ts

n me

0.7 %

Pre-use

Pre-use

Post-use

Total

Closed-loop potential

97.3 %

78.1%

175.4 %

Loop potential

97.3 %

85.9 %

183.2 %

37.0 % 4.3 %

+

-

Pre-use

Post-use 1.9 %

33.2 %

10.4 %

)

)

48.2 %

)

) s itie (D A C bil ling ts ( ( a n i l l e re a d cyc os em ctu an re isp lac ts om ufa i D p f n fr ne Re Ma Be 3 1–

4 (B

Straw used in place of reed insulating panels

250 200 150 100 50 0 -50 -100 -150 -200

8.1 %

4 3–

Pre-use

Post-use

Total

Closed-loop potential

48.2 %

82.6 %

130.8 %

Loop potential

48.2 %

94.9 %

143.0 %

3.0 % 25.7 %

25.7 %

+

-

Pre-use

0.2 %

52.8 %

12.2 %

74.1 %

3)

Post-use 1.9 %

4)

4)

) s – – itie (D (B A1 C3 bil ling ts ( ( a n i l l e re a d cyc os em ctu an re isp lac ts om ufa i D p f n fr ne Re Ma Be Recycled crushed clay brick not included due to lack of data

Pre-use

Post-use

Total

Closed-loop potential

99.8 %

93.7 %

193.5 %

Loop potential

99.8 %

95.5 %

195.3 %

In each building element, solid timber building components make up the bulk of the raw materials. Since glues are avoided, these remain entirely within the biotic loop. Using ­timber from certifiably sustainably managed forests ensures that sufficient wood is grown to replace it. In its timber floors and walls, the building sequesters large quantities of carbon, which are released at a later date as CO2 via energy reclamation after the building is dismantled. However, the solid wood is also very well suited for material downcycling post-use in multi-step cascade utilisation. The insulating materials from the stalks or leaves of the bulrush plant (typha) and the glue-free wood fibre insulation, as well as the green roof vegetation, can all be materially recycled post-use as compost. In the exterior wall, the dry-laid bricks of the facing wall make up the largest-mass portion of the incorporated materials. Since most of the materials used in their manufacture are primary resources, the result is a moderate pre-use loop potential. However, most of the bricks will be highly suitable for reuse after dismantling. It is assumed that approximately a quarter of the brick mass will undergo a post-use downcycling process to make aggregate; this is due in part to the mutual cementing that is necessary in the cornice and lintel areas, but also to the economic cost represented by selective dismantling. The recycled crushed brick and foam glass materials enter into the pre-use portion of the loop potential; post-use, the crushed brick can be easily separated out and recovered and is fully reusable 1:1, while in the case of the foam glass gravel only 70 % is expected to be downcyclable because of the necessary compaction of the material and the economic consider­ ations for selective dismantling. The loosely laid waterproofing membranes are notable primarily in an indirect way: they make the recovery and separation by type of the solid timber panels in the roof and floors possible.

Loop potential key 250 200 150 100 50 0 -50 -100 -150 -200

M

-

Pre-use

2.5 %

)

–3

A1

( re

e

lac

p Re

4)

0.6 % 8.5 %

(B

3–

(C al

Post-use 44.8 %

11.6 %

4)

) ies D ilit g ( iab yclin l d c os an re sp Di fits from e n Be

ts

n me

Post-use

9.7 %

69.1 %

tu

fac

u an

23.9 %

28.4 %

+

Pre-use Recycled materials (MRC, see B2 p. 64) Regrown raw materials

Pre-use

Post-use

Total

Closed-loop potential

97.5 %

90.0 %

187.5 %

Loop potential

97.5 %

99.1 %

196.6 %

Reusable materials Recyclable materials Downcyclable materials from certifiably ­sustainable renewable sources Energetically recoverable materials from ­certifiably sustainable renewable sources Downcyclable materials Energetically recoverable materials from renewable sources

171

Example 08: Metal Bathroom: Steel Skeleton Construction / Weather-Resistant Structural Steel Panel Facade Closed-loop design for the bathroom Materials

Support structure and foundation • steel skeleton construction • with cavity insulation Exterior cladding • weather-resistant structural steel • stainless steel /aluminium subconstruction Interior cladding • expanded metal panels • aluminium subconstruction Interior floor coverings • solid timber planks • floor sleeper subconstruction Insulation • wood shavings fill • cork insulating panels • fibreboard insulation Doors / Windows • aluminium post-and-beam • triple glazing with capillary plates • flashing with lapped EPDM connecting foils Mechanical ventilation The entire construction is designed to achieve as great a loop potential as possible. Its not inconsiderable manufacturing costs are expected to be outweighed at the end of the building’s use phase by the ease of dismantling, the clean separability by type of the materials and their very high resale price due to their increased future value. This case contrasts sharply with that of a solid construction with cemented tiles, in which the demolition materials are either downcycled or deposited in landfills. The steel skeleton structure, the various types of metal cladding and the subconstruction are all recycled within a closed loop system, undergoing material recovery without loss of quality. Similarly, the bathroom fixtures are not made of the usual synthetic or mineral materials, but rather of stainless steel or steel sheet, which is provided with a traditional enamel coating. The stainless steel panels on the interior walls are polished to a mirror finish or corundumblasted. The resulting soft golden shimmer of the surface is reflected in the patina of the reused oak planks on the floor. A translucent, light-scattering capillary plate is integrated in the insulating glass. 172

Partial view Horizontal section Vertical sections Scale 1:20

Example 08

173

Loop Potential of the Construction Materials: Recycling Path / End-of-Life Potential

Reuse

Wiederverwendung Sand fill Wiederverwendung Wiederverwertung Recycling

Exterior wall construction (U-value: 0.19 W/m2K)

• 4-mm weather-resistant structural steel ­cassettes, clipped on • stainless steel and aluminium bracket and T-profile subconstruction, secured with screws • 0.2-mm high-density polyethylene (PE-HD) windproofing, vapour-permeable, sd: 0.025 m, overlapped and stapled • 100-mm lignin-bonded fibreboard insulation, multiple layers, λ: 0.04 W/mK, anchored • 16-mm tongue-and-groove MDF panels, vapour-permeable, sd: 0.165 m, secured with screws • 180/180/8.5-mm galvanised steel HEB ­support profile, secured with screws • 180/70/8-mm secondary construction of ­galvanised steel fi support profiles, secured with screws • 180-mm spruce and fir wood shaving fill with soda ash and whey, λ: 0.05 W/mK, poured in • 22-mm OSB/3 panel, with formaldehyde-free bonding agents, airtight bonding at joints, secured with screws • 40/60-mm untreated spruce structural timber as interior facing, secured with screws • 12.5-mm plasterboard, adapted for bathroom applications, secured with screws Windows (U-value: 0.8 W/m2K)

• 50/140-mm aluminium post-and-beam construction, anthracite powder-coated, secured with screws • triple glazing with 30-mm integrated capillary plates, polymethyl methacrylate (PMMA) with a glass mat coating on both sides, λ: 0.8 W/mK, clamped; windproof flashing with EPDM connecting foils • brass-coated steel mesh impact protection Interior wall construction and fittings

• 1.5-mm stainless steel panels, reinforced with crosspieces, corundum-blasted matte and mirror-polished surfaces • attached to welded-on L-angles, natural r­ubber profiles wedged into panel joints, ­silicone used in wall joints • stainless steel U-profile subconstruction, secured with screws • 22-mm OSB/3 panels with formaldehyde-free bonding agents, secured with screws 174

• 125/50/0.6-mm aluminium C-profile subconstruction, secured with screws • 125-mm spruce and fir wood shaving fill with soda ash and whey, λ: 0.05 W/mK, poured in • 22-mm OSB/3 panels with formaldehyde-free bonding agents, secured with screws • 40/60-mm untreated spruce structural timber as interior facing, secured with screws • 12.5-mm plasterboard panels, secured with screws • 700/530/60-mm enamelled steel sheet ­washbasin, white, seated • 22-mm washstand of solid oak, secured with screws, silicone at wall joints • 1,000/2,600-mm enamelled steel sheet ­bathtub, on supports, silicone at wall joints • steel bathtub support, sound-insulated, placed • stainless steel toilet with wooden toilet seat varnished black

Floor constructions

Wiederverwertung Cork insulating panels, steel ­sWeiterverwendung upport profile, trapezoidal sheet, weather-resistant structural steel Weiterverwendung cassette, stainless steel panels, Weiterverwertung stainless steel subconstruction, expanded stainless steel panels, Weiterverwertung enamelled steel sheet or stainless Herstellerrücknahme steel fixtures, aluminium subconHerstellerrücknahme struction and suspended ceiling Kompostierung system, aluminium window frames, Wiederverwendung Wiederverwendung steel mesh, copper and aluminium Kompostierung floor heating system, steel sheet Energetische Verwertung Wiederverwertung drains, plasterboard Wiederverwertung Energetische Verwertung

Kompostierung

Kompostierung Energetische Verwertung Energetische Verwertung

Deponie Kl. Deponie Kl. Gefahrensto Deponie Kl. Gefahrensto

Verfüllung/„ Verfüllung/„ Deponie Deponie Kl. Kl. Deponie Deponie Kl. Kl.

Weiterverwendung Wiederverwendung Weiterverwendung Wiederverwendung

Deponie Verfüllung/„ Deponie Kl. Kl. Verfüllung/„ Gefahrensto Deponie Kl. Gefahrensto Deponie Kl.

Downcycling Weiterverwertung

Verfüllung/„ Deponie Deponie Kl. Kl.

Further use

Wiederverwertung Wiederverwendung Weiterverwertung Wiederverwertung Spruce structural timber and floor sleepers, reused timber planks, Herstellerrücknahme wooden washstand, MDF panels, Weiterverwendung Wiederverwertung Herstellerrücknahme Weiterverwendung OSB/3 panels, low-density poly­ ethylene (PE-LD) vapour barrier, Kompostierung Weiterverwertung Weiterverwendung Kompostierung plate glass Weiterverwertung Manufacturer take-back

• 22-mm oiled oak planks, reused, tongueand-groove joints with concealed screws, joints sealed with clamped natural rubber, ­silicone at wall joints • 40/60-mm untreated oak floor sleepers, secured with screws • 30-mm underfloor heating system panels in between: copper pipes with aluminium thermal conducting sheet, seated in • 30-mm cork insulating panels, 100 % cork bark, λ: 0.04 W/mK • 22-mm OSB/3 panels with formaldehyde-free bonding agents, secured with screws • 48.5/250-mm galvanised steel trapezoidal sheet, point-attached with screws onto a Wiederverwendung ­natural rubber elastomer underlay Wiederverwendung • bulk sand fill poured loosely into the troughs of the trapezoidalWiederverwendung sheet Wiederverwertung • 180/180/8.5-mm galvanised steel HEB Wiederverwertung ­support profiles, secured with screws Wiederverwertung Weiterverwendung • aluminium C-profile subconstruction, secured with screws Weiterverwendung • aluminium suspended ceiling system, Weiterverwendung Weiterverwertung threaded supports, secured with screws Weiterverwertung • 1-mm expanded stainless steel panels, ­suspended Weiterverwertung Herstellerrücknahme • mechanical ventilation, galvanised steel Herstellerrücknahme sheet ducts Herstellerrücknahme Kompostierung

Verfüllung/„ Deponie Kl. Verfüllung/„ Deponie Kl. Deponie Kl.

Energetische Weiterverwertung Herstellerrücknahme Energetische Verwertung Verwertung Herstellerrücknahme

Composting Kompostierung Herstellerrücknahme

Kompostierung Fibreboard insulation, wood ­shavings fill Energetische Kompostierung Energetische Verwertung Verwertung Energetic reclamation

Energetischepolyethylene Verwertung(PE-HD) High-density windproofing, natural rubber ­profiles, silicon seals, adhesive tape, plastic anchors Landfill class 0 / Fill Verfüllung/„Landfill“

Deponie Kl. 0 Verfüllung/„Landfill“ Deponie Kl. 0 Verfüllung/„Landfill“ Deponie Kl. 0I & II Deponie Kl.

Landfill classes I and II

Deponie Kl. I & II Deponie Kl. III & VI Deponie Kl. I & II Gefahrenstoff Deponie Kl. III & VI Gefahrenstoff Landfill classes Deponie Kl. IIIIII&and VI IV / ­ Gefahrenstoff Hazardous materials

Deponie Kl. Deponie Kl. Kl. Deponie Gefahrensto Gefahrensto

Deponie Kl. Gefahrensto

Example 09

Example 09: Glass Bathroom Steel Skeleton Construction /Channel Glass Facade Detachably jointed – recycling in the bathroom

Materials

Support structure • steel skeleton construction • with cavity insulation Exterior cladding • channel glass • in aluminium subconstruction

Partial view Vertical section Scale 1:20

Interior cladding • single-pane tempered glass on • aluminium subconstruction Interior floor coverings • glass ceramics • aluminium supporting subconstruction Insulation • granulated cork fill • cork insulating panels • fibreboard insulation Doors / Windows • stainless steel frames • triple glazing • flashings with lapped EPDM connecting foils Mechanical ventilation The design experiments with the aesthetic possibilities of glass as a working material. At the same time, it illustrates practically all levels of the cascade utilisation model for glass. Trapezoidal sheet is set into the steel skeleton and its troughs are filled with an easily suctioned and reusable bulk fill of sand for improved sound insulation. The remaining room surfaces are composed of structural and insulating panels made from renewable resources. Cork used as insulation is notable here for its moisture resistance, but it is also 100 % recyclable or has already been manufactured from old bottle corks. The interior wall cladding of the bathroom is made of sandblasted glass; its colour complements that of the waterproof backlit glass ceramic surface of the floor. The cloudy structure of the floor varies from white to grey-brown and is a result of the process in which old, metal-coated insulating glass panes, originally designed for sun protection, are recycled. The rear-ventilated outer shell, sectioned horizontally by aluminium profiles and designed, like the entire construction, to be easily disassembled, is made from inexpensive channel glass. Stainless steel window frames complete the somewhat cool appearance of the room. 175

176

Example 09

Loop Potential of the Construction Materials: Recycling Path / End-of-Life Potential

Wiederverwendung Glass ceramic tiles, sand fill

Verfüll Depon

Wiederverwendung Wiederverwertung

Verfüll Depon

Reuse

Recycling

Horizontal section Vertical section Scale 1:20 Exterior wall construction (U-value: 0.23 W/m K) 2

• 331/60/7-mm channel glass, double-layered U-profile cast glass, clipped on • 83-mm aluminium subconstruction frame with spacers, secured with screws • 16-mm tongue-and-groove MDF panels, vapour-permeable, sd: 0.165 m, secured with screws • 60-mm lignin-bonded fibreboard insulation, two layers, λ: 0.04 W/mK, loosely laid • 8-mm fibreboard, sd: 1.48 m, airtight bonding at joints, secured with screws • 180/180/8.5-mm galvanised steel HEB ­support profile, secured with screws • 180/70/8-mm secondary construction of ­galvanised steel fi support profiles, secured with screws • 180-mm granulated cork fill cavity insulation from 100 % recycled bottle corks, λ: 0.05 W/mK • 22-mm OSB/3 panels with formaldehyde-free bonding agents, airtight bonding at joints, secured with screws • 40/60-mm untreated spruce structural timber as interior facing, secured with screws • 12.5-mm plasterboard panel, secured with screws Windows (U-value: 0.9 W/m2K)

• 70-mm stainless steel frame, triple glazing, windproof flashing with lapped EPDM ­connecting foils Interior wall construction and fittings

• 8-mm single-pane safety glass, sandblasted, glued onto aluminium toothed profile, joints sealed with wedged natural rubber profiles, wall joints with silicone • aluminium subconstruction rail with toothed profile counterpart, secured with screws • 12.5-mm plasterboard panels, secured with screws • 125/50/0.6-mm aluminium C-profile subconstruction, secured with screws • 125-mm granulated cork fill cavity insulation from 100 % recycled bottle corks, λ: 0.05 W/mK

• 12.5-mm plasterboard panels, two layers, secured with screws • 700/530/60 mm enamelled steel sink, white, inserted • 22-mm glass ceramic plate loosely laid as washstand counter surface, wall joints sealed with silicone • 22-mm washstand, solid oak, secured with screws • 1,000/2,600-mm enamelled steel sheet ­bathtub, on supports, silicone at wall joints • steel bathtub support, sound-insulated, placed • stainless steel toilet with black-varnished wooden toilet seat varnished black Floor construction

• 20-mm glass ceramic tiles, white, 100 % waste glass, loosely laid on natural rubber elastomer underlay, joints sealed with wedged natural rubber profiles, wall joints with silicone • aluminium support subconstruction, secured with screws • 50-mm stainless steel levelling spindles, height-adjustable • 21-mm spruce three-ply board, weight ­distribution, spot-placed under levelling ­spindles • 50-mm cork panel impact sound insulation, 100 % cork, λ: 0.04 W/mK • 48.5/250-mm galvanised steel trapezoidal sheet, point-attached with screws onto a ­natural rubber elastomer underlay Wiederverwendung • bulk sand fill poured loosely into the troughs of the trapezoidalWiederverwendung sheet • 180/180/8.5-mm Wiederverwendung galvanised steel HEB Wiederverwertung ­support profiles, secured with screws Wiederverwertung • aluminium C-profile subconstruction, secured Wiederverwertung Weiterverwendung with screws • 40/60-mm untreated spruce structural Weiterverwendung ­timber as interior facing, secured with Weiterverwendung Weiterverwertung screws Weiterverwertung • 12.5-mm plasterboard panels, two-ply, secured with screws Weiterverwertung Herstellerrücknahme • mechanical ventilation, galvanised steel Herstellerrücknahme sheet ducts Herstellerrücknahme Kompostierung Kompostierung Kompostierung Energetische Verwertung Energetische Verwertung

Wiederverwertung Weiterverwendung Granulated cork insulating fill, cork insulating panels, steel support ­pWeiterverwendung rofiles, trapezoidal sheet, stainless Weiterverwertung steel window frames, enamelled steel sheet and stainless steel fixWeiterverwertung tures, aluminium subconstruction, Herstellerrücknahme levelling spindles, steel sheet Wiederverwendung drains, channel glass, plasterboard Wiederverwendung Herstellerrücknahme Kompostierung Wiederverwertung

Depon Gefahr

Wiederverwertung Kompostierung

Depon Depon Gefahr Depon

Energetische Verwertung Further use Weiterverwendung

Weiterverwendung Energetische Verwertung

Depon Gefahr

Verfüll Depon Verfüll

Depon Depon

Gefahr Verfüll Depon Verfüll

Weiterverwertung Wiederverwendung Downcycling Weiterverwertung Spruce structural timber and floor Wiederverwendung Herstellerrücknahme sleepers, wooden washstand, Wiederverwertung MDF panels, OSB /3 panels, fibreHerstellerrücknahme Wiederverwendung Wiederverwertung board, three-ply boards, plate Kompostierung glass, single-pane safety glass, Weiterverwendung glass ceramic tiles Kompostierung Wiederverwertung Weiterverwendung Energetische Verwertung Weiterverwertung Energetische Verwertung Weiterverwendung Weiterverwertung

Depon Depon Verfüll

Depon Depon Gefahr Depon Gefahr

Depon Gefahr

Manufacturer take-back

Herstellerrücknahme Weiterverwertung Herstellerrücknahme

Kompostierung

Composting Herstellerrücknahme

Kompostierung Fibreboard Energetische Verwertung Kompostierung Energetische Verwertung Energetic reclamation

Energetische Verwertung Natural rubber profiles, silicone seals, elastomer underlay

Verfüllung/„Landfill“ Landfill class 0 / Fill

Deponie Kl. 0 Verfüllung/„Landfill“ Deponie Kl. 0 Verfüllung/„Landfill“ Deponie Kl. I & II Deponie Kl. 0 Landfill classes I and II Deponie Kl. I & II Deponie Kl. III & VI Deponie Kl. I & II Gefahrenstoff Deponie Kl. III & VI Gefahrenstoff

Landfill classes Deponie Kl. IIIIII&and VI IV / ­ Gefahrenstoff Hazardous materials

177

Part D  Completed Examples

Technological Loop: Urban Mines 01  RCR Arquitectes – Musée Soulages in Rodez (FR) 02  kadawittfeldarchitektur – Lausward Power Plant in Düsseldorf (DE) 03  Durisch + Nolli – Training Centre in Gordola (CH) 04  Wandel Hoefer Lorch + Hirsch – Documentation Centre in Hinzert (DE) 05  Steven Holl Architects – The Nelson-Atkins Museum of Art in Kansas City (US) 06  Graber & Steiger – Window Factory in Hagendorn (CH) Biotic Loop: Renewable Resources 07  Cukrowicz Nachbaur Architekten – Community Centre in St. Gerold (AT) 08 Michael Green Architecture – Wood Innovation and Design Centre in Prince George (CA) 09  Werner Sobek – Aktivhaus Residential Estate in Winnenden (DE) 10  Proarh – Holiday Home in Kumrovec (HR) 11  Georg Bechter Architektur + Design – Residence in Vorarlberg (AT)

190 192 194 195 196

Techno-Biotic Loop 12  architekturwerkstatt Bruno Moser – Office Building in St. Johann in Tyrol (AT) 13  NKBAK – European School in Frankfurt am Main (DE) 14  Dorte Mandrup – Wadden Sea Centre in Ribe (DK)

198 200 202

Locally Sourced Materials 15  Boltshauser Architekten with Martin Rauch – the Rauch House in Schlins (AT) 16  spaceshop Architekten – Residence in Deitingen (CH) 17  2012 Architecten – Villa Welpeloo in Enschede (NL)

204 206 208

Recycled 18  Lendager Group – Upcycle House in Nyborg (DK) 19 David Chipperfield Architects Berlin – Folkwang Museum Building Extension in Essen (DE) 20 Alvaro Siza with Finsterwalder Architekten – Cultural Institute, Formerly Hombroich Rocket Station near Neuss (DE) 21  Amateur Architecture Studio – History Museum in Ningbo (CN)

Administrative building, Reutlingen (DE) 2002, Allmann Sattler Wappner

180 182 184 186 187 188

210 211 212 213

Few built examples exist today that meet the requirements for urban mining-compatible construction. Complex ­buildings with large space allocation plans and stringent specifications (e.g. for fire safety), in particular, represent a challenge when it comes to detachable construction and selecting recyclable materials. The completed buildings featured here were often not designed or built with an eye to an urban mining principle at all, but the results of completely different motivations: a particular material aesthetic, the advantages of an ­ecologically conscious approach in general, short construction times, series fabrication economies of scale or low ­construction costs. For this reason they often fulfil only parts of an urban mining strategy: concepts for minimisation or the repurposing of space, a high proportion of renewable resources, a facade as a resource storage, the avoidance of building component layers (sufficiency thinking), sound building biology, soil conservation, local sourcing of materials or the utilisation of ­recycled materials. In the descriptions accompanying the drawings, detachable connections and recyclable materials are elucidated in greater detail, while the standard materials and joining methods are mentioned only with respect to function.

179

b

a

Steel as an Interior and Exterior Surface

a b

a

Musée Soulages Rodez, FR 2014 Architects: RCR Arquitectes, Olot

c

c c

c c

a

b

a

a

The materials used in the exposed surfaces were chosen for design reasons: the weathering steel on the exterior facade makes reference to the reddish ­limestone that is typical for the region and is found in the nearby cathedral, while the ­interior cladding of black steel complements the exhibited works of the artist Pierre Soulages. Black is the hallmark colour of this internationally recognised painter of non-representational art, who has been ­creating monochrome black surfaces exclusively for almost 40 years. Aside from its aesthetic qualities, steel is almost limitlessly recyclable, making it a ­perfect closed-loop material. The variability in its uses as an exposed surface material was explored fully in this building: In addition to the large-scale panels of weathering steel used in the facade, there are also longitudinal steel bar grate bridges over a water basin, horizontally placed steel plates used as a park boundary and vertical sun protection louvres of the same material attached to the outside of the post-and-beam facade. The visible floor coverings and wall and ceiling claddings in the interior are all made from black plate, as are the benches and seating alcoves in the window reveals, as well as the free-standing movable partitions.

Sections • Floor plan Scale 1:500 Facade section of the exhibition cube Scale 1:20  Vertical section • Horizontal section of the core structure’s north facade Scale 1:20

180

b

A

B

aa

bb

cc

a

b

c c

a

b

Technological Loop: Urban Mines

2

3

4

9

10

1

11

d

d

4

7

8

5

12

13

8

14

B

13

13

7

6

14

A 1 Exterior wall construction: 6-mm weathering steel stainless steel support 120-mm thermal insulation 360-mm reinforced concrete 520-mm installation space 2≈ 12.5-mm plasterboard 2 Roof edge: 6-mm weathering steel parapet coping EPDM joint seals 3 Roof construction: 30 ≈ 30-mm weathering steel grate 340-mm spacer, height-­ adjustable waterproofing sheet 180-mm thermal insulation vapour-proofing layer 120-mm reinforced concrete

dd 100-mm installation space 60-mm soundproofing layer 0.7-mm perforated steel sheet, coated 4 Steel sheet wall frieze, coated white 5 False ceiling construction daylight-scattering ceiling panel direct / indirect acoustics and ­artificial lighting perforated steel sheet, coated white 40-mm sound insulation, on 160/300-mm steel profile frame 6 Floor construction: 6-mm black plate 100-mm concrete levelling course 350-mm reinforced concrete

100-mm thermal insulation 100-mm rear ventilation 6-mm weathering steel   7 180-mm weathering steel fi profile   8 6-mm weathering steel   9 1012/180-mm pre-oxidised sun protection louvre 10 Insulated glass 11 Weathering steel reveal, ­removable for glass replacements 12 Insulated glass skylight 13 180/700-mm weathering steel ­facade mullion, welded 14 20-mm black plate window bench

181

Steel Structure with Clip-On Steel Facade Lausward Power Plant Düsseldorf, DE 2015 Architects: kadawittfeldarchitektur, Aachen

A B C D

District heat extraction Turbine hall Boiler house “Window to the City”

C

D

B

es

sett

cas

A

The detachably constructed facade of the power plant was installed within a very short time and also promises to be easy to dismantle, as the inner steel cassettes are attached to one another and fixed to the steel structure with screws. The joints between the cassettes are sealed with clamped sealing trips. Thermal and sound insulation is packed into these cassettes and fixed in place by the screw-fastened steel support of the outer shell. The corner-crimped exterior facade cassettes (which are custom-made) are clipped onto profiles in the subconstruction and interlocked. In the light gaps, additional perforated-sheet cassettes make the gaps appear dark during the day, while allowing the illumination to shine through at night. The steel profiles of the support structure are connected to one another with screws. These easily detachable connections allow the building to be readily disassembled, after which the individual materials can be effortlessly separated by type. At the end of its service life, the entire building or just its single components can be reused. When the building is finally dismantled it becomes an urban mine. Instead of incurring disposal costs, the sale of the steel, i.e. the main building material in the structure, will generate a profit.

182

ture

truc

rt s

ppo

l su

stee

tion

the

rma

ula l ins

rail ction for dule stru ace mo ubcon ) surf s on aps ttes acti g sse s refr acklit de ca es ette a b sett ass (fac cas de et c she faca ted ra o perf

1

Technological Loop: Urban Mines 1 1

Axonometric projection of the plant Exploded view of the facade Vertical section • Horizontal section Scale 1:20

2 2

2 2

3 3

1 Roof edge: 400/1.0-mm steel sheet parapet coping and splice plate, RAL 9006 trapezoidal sheet (on inside) rolled steel profile subconstruction rolled steel profile parapet support 2 Roof construction: waterproofing sheet thermal insulation trapezoidal sheet rolled steel profile beam 3 Exterior wall “frame” construction 260-mm steel IPE profile beam 160/600 ≈ 1.0/1.25-mm crimped steel sheet facade system cassette 160-mm thermal insulation 60 ≈ 3-mm thermal separation module rail subconstruction 400/1.0-mm steel cassette facade cladding, RAL 9006 4 Wall “gap” construction 600/1.5-mm perforated sheet (RV 12/16) cassettes, RAL 9005 steel cassette as refraction surface, RAL 9016 module rail subconstruction 60 ≈ 3-mm thermal separation 160-mm thermal insulation 160/600 ≈ 1.0/1.25-mm crimped steel sheet facade system cassette 260-mm steel IPE profile beam 5 Tubular fluorescent light

3 3

aa

a a

a 5 a 4

5

4

a a

3

5

3 4 4

5

183

Elevated Steel Structure with Stainless Steel Shell Training Centre Gordola, CH 2011 Architects: Durisch + Nolli, Lugano

aa

a

a

b

The elevation of the building leaves the topography of the location essentially unchanged, allowing the Magadino Plain to “flow” underneath the building without interruption. As a precious resource, the soil was conserved to the extent possible. By pla­cing the required outside facilities (e.g. parking spaces and ­storage areas) under the building, the architects were able to halve the amount of sealed surface. The choice of materials and the efficiency of the construction facilitate repairs and allow for an uncomplicated dismantling process. The steel structure consists of a few simple and identical building elements that repeat in series. The facade and exterior cladding of the saw-tooth roof are all composed of stainless steel. The inner roof cladding of galvanised trapezoidal sheet is perforated to ensure both the appropriate absorption of machine noise from the workshops and optimal acoustics for the classrooms on the upper level. The separation of structure and installation allows for great flexibility in adapting to future changes in technological developments. The numerous carefully planned media are suspended from the structure on open tracks and conform to its grid spacing of three metres, which corresponds to the allotted area at the workbenches. 184

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Technological Loop: Urban Mines

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1 Roof construction: 45/900/0.8-mm stainless steel trapezoidal sheet 60-mm battens  /counter battens vapour-permeable ­waterproof membrane battens 2≈ 80-mm thermal ­insulation vapour barrier 59/900/1-mm galvanised steel trapezoidal sheet, painted perforated girders with acoustic inserts 2 25-mm multi-wall skylight, translucent PMMA

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3 Truss: upper and lower chords: ­canted steel sheet secured with screws, truss members: 75-mm Ø steel tube 4 Suspended installation track 5 Wall construction: 45/900/0.8-mm stainless steel trapezoidal sheet 2≈ 40-mm steel Z-profile, ­vertical/horizontal 40 + 80-mm thermal ­insulation 80/500-mm reinforcing ­galvanised steel sheet wall cassette, painted steel HEA 200 profile ­supports

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Load-Bearing Building Shell of Weathering Steel Documentation Centre Hinzert, DE 2006 Architects: Wandel Hoefer Lorch + Hirsch, Saarbrücken

The design of the Documentation Centre is char­acterised by a sufficiency-inspired treatment of the utilised material and thus of its ­resources. The building shell acts as structure and facade at the same time, manufactured ­entirely of the closed-loop material steel. In the factory, twelve large-scale elements were fabricated from over 3,000 different CNC-milled triangular plates of weathering steel and then welded together on site. The angles between the individual panels were chosen to ensure that the entire construction would form a sufficiently rigid folded plate structure. After welding, the surface of the steel was sandblasted and uniformly oxidised. The welded metal outer shell is vapour-impermeable and thus – unlike the principally pref­ erable vapour-permeable constructions – ­requires perfectly sealed vapour-proofing on the inside of the insulation. This is provided by 1.5-millimetre-thick galvanised steel sheeting, which is screwed onto the steel sheet cassette mounts of the insulation. The joints ­between the sheet panels and the drilled holes are sealed with tape. Through incon­ spicuous holes drilled into the outer steel skin, the vapour pressure that builds up in the interstices of the construction during rapid heating of the material is equalised.

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1 Exterior wall construction: 14-mm pre-oxidised ­weathering steel, coated with hot paraffin wax, thermally decoupled ribs with a 95 – 300-mm air layer between them 2≈ 80-mm thermal insulation U-shaped sheet metal cassettes fastened to the ribs for mounting the insulation 1.5-mm galvanised steel ­vapour-proofing installation space 95-mm aluminium support 17-mm timber composite board, partially perforated, with sound-insulating fleece on the back and birch veneer on the exposed side, agraffefastened onto support 2 Clipped HEA 300 steel profile 3 5/5-mm grooved drip edge 4 Thermal insulating glazing 5 Weathering steel profile ­welded from ¡ 50/10 mm + ¡ 180/10 mm 6 Aluminium windows with ­insulating glass 7 Thermal decoupling

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Technological Loop: Urban Mines

Recyclable Channel Glass Facade The Nelson-Atkins Museum of Art Kansas City, US 2007 Architects: Steven Holl Architects, New York

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Unlike the neoclassical main structure, the building’s extension reflects the local topography and appears above ground in several small-scale, elegantly light cube-like structures. The bulk of the floor space lies hidden beneath the lawns of the surrounding park. Like lanterns, the two-storey glazed structures funnel daylight through scoop-shaped room elements into the lower exhibition levels. The supports and beams of the above-ground buildings are made of steel, the ceilings of trapezoidal sheet with concrete topping. The skeleton structure is either covered by the ex­terior claddings or concealed within the ­double-skin translucent walls. The latter combine with a few strategically placed viewing openings to dominate the effect of the interior. The translucent walls consist of storey-height, double-skin channel glass bands in aluminium frames, with capillary plates in between to ­adequately scatter the light and thermal insu­ lation. The capillary plates are composed of small acrylic (PMMA) tubes arranged in a honeycomb pattern and coated with glass ­matting. They are spot-fastened to the channel glass panes with silicone. Frames, channel glass, PMMA tubes and glass matting can all be separated by type and recycled.

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1 Roof edge: 0.8-mm aluminium sheet waterproofing sheet 13-mm OSB panels 75-mm thermal insulation, double-layered 75-mm trapezoidal steel sheet steel profiles 2 Roof construction: waterproofing sheet, ­multilayered 150-mm thermal insulation vapour-proofing layer 90-mm reinforced concrete 75-mm trapezoidal steel sheet steel beam 10-mm composite timber acoustic panels, perforated 25-mm aluminium support with overlying acoustic ­insulation 3 Exterior wall construction: 57/400/10-mm U-shaped channel glass with reduced iron fraction, etched texture, coated 24-mm capillary tube ­inserts, glass-mat-coated poly(methyl methacrylate) (PMMA) tubes 27-mm air layer 57/400/6-mm U-shaped channel glass with reduced iron fraction, sandblasted, in 110-mm ­aluminium frame galvanised steel grating 100/100-mm suspended steel tube 19 mm steel rods 2≈ 9.5-mm laminated safety glass for sun and light protection, etched on the inside 4 Floor construction: 10-mm ash wood parquet 90-mm reinforced concrete 75-mm trapezoidal steel sheet

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Steel Structure with Lightweight Synthetic Shell Window Factory Hagendorn, CH 2006 Architects: Graber & Steiger, Lucerne

The expansion of the window factory borders on the adjacent nature conservation area, ­huddled under a large green roof. In response to the sensitive building location, the archi­ tecture features a trellis framework for native plants placed in front of the facade. The roof is designed as a wetland meadow and pre­ pared for the weight of a permanent retention area with excavated material and crushed brick. The large roof overhang protects the loading area from the weather, while also providing shade for the storey-high translucent facade surfaces to prevent overheating in the summer. Maximum and therefore energy-saving day­ light utilisation is achieved by way of light­ weight, translucent, partially transparent walls as well as light-scattering skylights. The steel support structure of the roof mainly consists of wide span trusses, complemented by an exposed secondary construction. The post-and-beam facade is made of timber and fitted with readily recyclable polycarbon­ ate panels or steel gates with glass or acrylic inserts. The materials reflect the tension inherent at the intersection of commercial location and landscape. Although the timber and untreated copper at the roof edge will develop a patina over time, the ageing of the varnished steel ­elements and the synthetic shell is not recog­ nisable.

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Technological Loop: Urban Mines

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1 Roof edge: 3,900/700/1.6-mm (approx.) crimped raw copper facades and parapet coping timber composite panels and slat supports 2 Roof construction: native vegetation green roof 120-mm growing medium, excavated materials and crushed brick, with 50-mm permanent water retention 30 – 40-mm drainage matting root barrier bitumen waterproofing, multilayered separating sheet 2≈ 100-mm thermal insulation vapour-proofing sheet (hall interior) 111-mm varnished trapezoidal sheet rolled steel profile truss with auxiliary girders, ­varnished 3 1-mm sheet flashing element, varnished and ­insulated 4 Timber ventilation flaps, varnished and insulated, attached via varnished gusset plate 5 Untreated larch post-and-beam construction with larch capping strip 80-mm polycarbonate chamber plate insert, ­translucent rolled steel profile support, varnished, attached via varnished gusset plate 6 Floor construction: 30-mm concrete surface course 350-mm reinforced concrete

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189

Timber Panel Construction with Environ­ mentally Friendly Insulation Community Centre St. Gerold, AT 2009 Architects: Cukrowicz Nachbaur Architekten, Bregenz

The Community Centre houses the municipal office, a kindergarten and a village store. Together with the retaining wall towards the hillside, it forms the new village square. The timber materials used in the building, which is the first four-storey timber building constructed in Vorarlberg, were sourced from the surrounding forests and processed in regional carpentry firms. The exterior cladding and window frames are made from untreated silver fir, as are the floor coverings, the doors and the ceiling and wall claddings inside. Glued wooden composite materials were completely avoided. Instead, the building incorp­ orates dowelled stacked board ceilings, and diagonal-board formwork replaces the usual

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reinforcing composite panels in the wall ­constructions. In the prefabricated storeyheight timber panel elements, supports and girders of solid wood are integrated in the wall structure. A ventilated cold roof keeps the attic floor free of condensate. With the exception of the sheep’s wool sound insulation and the vertical perimeter insulation, all of the insulating material used in the building shell and floors consists of wood fibre. Thus, from structure to detail, timber is consistently used as a building material throughout. Only the ground-contact building components of the two lower levels feature waterproof components made of pure concrete.

Biotic Loop: Renewable Resources

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1 Roof construction: 5-mm waterproofing sheet, double-layered 27/100-mm spruce formwork, tongue-and-groove 500-mm ventilation space with timber subconstruction 2-mm PE membrane, full-surface 27/100-mm spruce formwork, butt-jointed 40 – 230-mm sloping squared timbers, with interspersed wood fibre thermal insulation 100/180-mm squared spruce timbers, with interspersed wood fibre thermal insulation 220/100-mm timber beams, with interspersed wood fibre thermal insulation 27/100-mm spruce formwork, tongue-and-groove PE vapour barrier 110-mm installation cavity 30-mm sound insulation black fleece trickle protection 40/36-mm untreated silver fir slats 2 Silver fir window frames, sanded smooth, with triple glazing 3 Solid silver fir window ledge, planed 4 Exterior wall construction: 30/50 –120-mm silver fir battens, rough-sawn 30/50-mm spruce battens, painted black 30/50-mm spruce counter battens /rear ventilation black paper wind-sheathing Prefabricated element: 25/80 –150-mm diagonal tongue-and-groove spruce formwork, 60/125-mm spruce uprights, wood fibre insulation between Prefabricated element: 25/80 –150-mm diagonal tongue-and-groove spruce formwork, 60/200-mm spruce uprights, wood fibre insulation between 25/80 –150-mm diagonal tongue-and-groove spruce formwork PE vapour barrier spruce battens, interspersed with 40/50-mm installation cavity and sheep’s wool thermal insulation 20/50 –120-mm silver fir formwork, tongue-and-groove 5 Floor construction: 27/80 –100-mm silver fir plank flooring, rough-sawn, tongue-and-groove, nailed down 62-mm floor joists, interspersed with crushed brick fill 30-mm wood fibre impact sound insulation 220-mm dowel-jointed stacked board timber installation cavity 40-mm sheep’s wool sound insulation 15-mm gypsum fibreboard 26-mm installation cavity 30-mm sheep’s wool sound insulation black fleece trickle protection 40/35-mm untreated silver fir slats

191

Timber High-Rise Wood Innovation and Design Centre Prince George, CA 2014 Architects: Michael Green Architecture, Vancouver

As Canada’s first timber high-rise, the WIDC stands as a testament to the high performance characteristics of timber as a building mater­ ial. The building is a research and education venue for the engineering and architecture ­disciplines. It incorporates regionally manufactured solid timber products made from various ­coniferous woods. The goal was to completely avoid the use of cement or concrete above the ground slab. The structure consists of a timber framework with a stiffening access core that is also made of wood. Composite constructions were not used, thereby favouring a simple dismantling process and postuse recycling.

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In a typical storey, the timber beams are joined to glued laminated timber supports via steel connectors embedded in the wood. Two layers of plywood elements of different heights are laid on top of these to create installation cav­ ities. They ensure the best possible flexibility in case the floor plan should change in future. Fire safety requirements are met through ­oversized timber and a sprinkler system. The encasing of elements for fire protection is ­obsolete, so the timber construction remains exposed and can be fully experienced. The facade sections alternate between storeyheight glazing and fixed fields clad in thermally modified wood. The building spandrels are covered with aluminium sheet.

Biotic Loop: Renewable Resources

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  1 Roof construction: waterproofing sheet, multiple layers 200-mm thermal insulation, multiple layers 100 –140-mm (approx.) tapered insulation vapour barrier 25-mm plywood panels 19-mm plywood panels 239-mm cross-laminated timber, seven-ply 2 Cavity 19/40-mm battens acoustic fleece 24-mm sound insulation 320/500-mm glued laminated timber beam 3 Exterior wall construction: aluminium sheet 80-mm thermal insulation vapour-proofing layer 4 Timber /aluminium post-and-beam facade triple glazing wood slat blinds 320/320-mm glued laminated timber support 5 Floor construction: 9-mm carpet 7-mm impact sound insulation 99-mm cross-laminated timber, three-ply 169-mm cross-laminated timber, five-ply 220/500-mm glued laminated timber beam 6 Heating and supply duct 7 Installation channel: 2≈ 13-mm plywood panels 2≈ 25-mm sound insulation 8 installation space: 89/40-mm timber plank spring-loaded hollow metal rail 50-mm sound insulation 2≈ 16-mm plasterboard cavity 19/40-mm battens acoustic fleece 24-mm sound insulation 320/500-mm glued laminated timber beam  9 Sprinkler 10 Exterior wall construction: 30-mm thermally modified cedarwood sheathing, varying widths, charred or untreated surfaces 13-mm weather-resistant plywood strip 10-mm horizontal timber board windproofing sheet 13-mm fibreboard 165-mm thermal insulation 18-mm fibreboard 16-mm plasterboard 11 Ground floor construction: Polished reinforced concrete Perimeter insulation on facing side

Section • Floor plan Scale 1:750 Vertical section Scale 1:20 Axonometric view

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Prefabricated Houses in Variable Module Design Aktivhaus Residential Estate Winnenden, DE 2016 Architects: Werner Sobek, Stuttgart

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The residential estate in Winnenden opens up a new dimension in the construction of pre­ fabricated housing. Against the backdrop of a worldwide population explosion, and driven by the conviction that meeting the ­associated economic, ecological and socio­ logical challenges requires a new way of ­dealing with the built environment, the archi­ tects designed a modular system that minim­ ises resource consumption, is affordable and nevertheless offers individuals a comfortable living space. In Winnenden, 38 of the series-produced ­timber panel construction modules form an ensemble of two-storey buildings in which 200 refugees will find accommodation for approximately three years. Afterwards the houses will be made available to low-income citizens. The modules are prefabricated to a very high degree, ranging from the finished exposed ­timber panels to the buildings’ technical equip­ ment. Composite materials have been avoided and reinforced concrete has only been used in the foundations. The system offers a large array of design ­variants, since it is not based on identical ­building elements but rather on a uniform ­joining method for the components. The ­elements can therefore differ in their dimen­ sions and can be arranged according to need.

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1 1 Roof construction: waterproofing sheet 60 – 40-mm tapered insulation 120-mm thermal insulation vapour-proofing layer 140-mm cross-laminated timber ceiling 60-mm squared timber 15-mm spruce three-ply boards 2 200/280-mm main girder, glued laminated timber 3 Exterior wall construction: 27-mm larch wood slats, tongue-and-groove, ­rear-ventilated 20-mm spruce battens vapour-permeable facade membrane 100-mm thermal insulation 15-mm fibreboard 60 /160-mm timber posts, interspersed with 160-mm thermal insulation 15-mm OSB panels 15-mm spruce three-ply boards 4 Ground floor construction: 3-mm linoleum 25-mm dry screed 30-mm floor heating system panels 25-mm OSB panels 80/280-mm glued laminated timber auxiliary girders, interspersed with 280-mm thermal insulation 15-mm building slab 5 Reinforced concrete strip foundation

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5 Module floor plans Scale 1:250 Vertical section Scale 1:20

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Biotic Loop: Renewable Resources

Straw as Facade and Roof Covering Holiday Home Kumrovec, HR 2012 Architects: Proarh, Zagreb

When converting an old farmhouse into a ­holiday home, the architects focused on the purist utilisation of the materials straw, ­timber, glass and stone. Surrounded by hills, the traditionally constructed “hiza” (cottage) stands in the Zagorje region of northern Croatia. Structurally unsound and in a state of disrepair, it was renovated with due attention to the distinctive ­features of the local building heritage. In this process, although the existing form of the house was preserved, the originally open area on the ground floor is now taken up by a glass cube. The straw covering on the roof was replaced and extended to cover the entire facade. The gables were clad in larch wood. The straw was tied into individual bundles and treated with a fire-retardant soluble glass emulsion, after which it was attached with metal wire to the secondary timber construction of the roof and walls. The soft covering of the warm roof provides protection from cold, heat and moisture. Rainwater penetrates only a few centimetres into the material, which then dries. Since the outer straw layer is denser when it is wet, a moisture-variable vapour barrier would be required in more rain-prone regions. From the inside, the wall construction of old solid oak beams is readily apparent. They are stacked horizontally and jointed with a mixture of sawdust and glue.

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Roof construction: 300-mm bundled straw, attached with wire 100-mm battens and counter battens 1-mm underlay 24-mm timber formwork Wall construction: 300-mm bundled straw, attached with wire 100-mm battens and counter battens 1-mm underlay 100-mm solid oak

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Existing building

Renovation measures Straw Timber

Glass cube

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Load-Bearing Straw Walls Residence Vorarlberg, AT 2014 Architects: Georg Bechter Architektur + Design Langenegg

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The building clients’ wish for an environmentally friendly, inexpensive residence was implemented by the architects as an experimental straw house. The rapidly regrowing and compostable building material used in this single-storey house functions not only as thermal insulation but also as the load-bearing structure. The connection between the prefabricated roof module of screw-fastened timber box girders and the loosely stacked, untreated 70 ≈ 120 ≈ 240 cm straw bales it rests on is purely gravitational. Protected by a roof overhang, the walls are ­rendered with lime on the outside and loam on the inside. The floor of smoothed screed forms a solid composite with the waterproof concrete ground slab. In winter, this composite stores the radiant heat of the sun, which enters the house through the cleverly designed projecting roof. Only in the wall area do additional welded-on bitumen sheets offer protection from rising moisture. Recycled brick fill forms a drainage layer beneath the ground slab and a growth medium for vegetation on the green roof. The latter ­protects the loosely-laid waterproofing sheet, attached at the roof edges, from wind suction. As the roof was implemented as a rear-ventilated cold roof, vapour-proofing was unnecessary. In the interior, four wooden boxes enable an open room design concept. 196

Section showing the ­construction principle Floor plan Scale 1:300 Vertical section Scale 1:20

Biotic Loop: Renewable Resources

1 Roof construction: extensive green roof with recycled brick EPDM waterproofing membrane, multilayered, loosely laid 27-mm spruce three-ply boards ventilation space spruce box girder elements, joined with screws 700-mm straw bale thermal insulation 1 27-mm spruce three-ply boards 2 Exterior wall construction: 30-mm lime scale plaster

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1,200-mm straw bale thermal insulation 30-mm loam plaster Floor construction: 35-mm smooth composite screed 250-mm waterproof concrete 200-mm perimeter insulation 50-mm lean concrete blinding layer recycled brick fill reinforced concrete pile foundation Plinth render 140-mm perimeter insulation

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Timber Module Construction with a Copper Facade Office Building St. Johann in Tyrol, AT 2015 Architects: architekturwerkstatt Bruno Moser, Breitenbach am Inn

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The headquarters of a manufacturer of wood construction materials is one of four buildings the architect has designed using a modular system developed especially for the company. Conceived as a timber frame construction, it is designed around the maximum dimensions (2.80 ≈ 11.40 metres) of the OSB/4 panels produced by the company. Large quantities of identical elements can thus be prefabricated to ensure a short construction atime. The crosssections of the elements conform to the lar­ gest possible load each will be subject to. The cost of the resultant oversizing is balanced by the efficiency of prefabrication. The floors, box constructions of glued laminated timber

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beams with integrated installation spaces and OSB cover panels attached to both sides, are supported solely by the glued laminated timber columns. To enable the wood structure to remain visible, various compensatory measures were taken: additional outdoor emergency stairways were added as well as projecting copper-sheathed ceiling panels to act as flashover fire barriers. The latter simultaneously shade the room-height window ­glazing, providing physical protection for the timber. The value-adding copper was also used as facade cladding. In crimped perforated sheet form, it is attached vertically to the spandrels.

Techno-Biotic Loop

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Roof construction: EPDM waterproofing sheet, mechanically fastened 2≈ 140-mm thermal insulation vapour-proofing layer 22-mm OSB panels tapered battens 6≈ 30-mm OSB /4-cover panels 530/200-mm glued laminated timber beams cavity with cable conduits 30-mm OSB /4 cover panels, glazed Canopy construction: EPDM waterproofing sheet 22-mm OSB panels tapered battens 5≈ 30-mm OSB /4-cover panels 500/100-mm glued laminated timber beams 30-mm OSB /4 cover panels, glazed Timber aluminium window with triple glazing Floor construction: floor covering 10-mm impact sound insulation 18-mm tongue-and-groove OSB panels 32-mm tongue-and-groove OSB panels 30-mm OSB /4 cover panels 200/520-mm glued laminated timber beams cavity with cable conduits 60-mm crushed brick fill 30-mm OSB /4 cover panels 2≈ 20-mm plasterboard 500-mm suspended cable conduit 18-mm OSB /4 panels, glazed white Heating vent Grate of untreated larch wood slats EPDM waterproofing sheet 30-mm OSB panels 100/300 – 320-mm glued laminated timber girder 4≈ 30-mm OSB /4 cover panels, varnished Crimped copper sheet separating sheet 30-mm OSB panels Exterior wall construction: 85/44-mm vertical larch wood battens 85/44-mm rhomboid larch wood battens vapour-permeable facade sheet 32-mm fire-resistant fibreboard, tongue-and-groove 60/280-mm timber beams, interspersed with 2≈ 140-mm thermal insulation 22-mm OSB /4 cover panel, glazed white Ground foor construction: 10-mm floor covering 22-mm OSB panels 30-mm OSB panels vapour-proofing layer 60/140-mm battens, interspersed with thermal insulation 30-mm (approx.) levelling course 300-mm reinforced concrete

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Timber Module Construction with an ­Aluminium Facade European School Frankfurt am Main, DE 2015 Architects: NKBAK, Frankfurt am Main

Isometry Floor plan scale  1:500 Vertical sections • Horizontal section Scale 1:20

Thanks to the time-saving efficiency of the ­prefabricated module construction method, the containers typically required for a tempor­ ary school expansion, currently licensed for a five-year period, were not needed. It took only 17 months from the initial planning enquiries to commissioning to create a building of sophisticated design and flexible structure. The school building is characterised by the module dimensions of 9 metres (classroom depth) by 3 metres, where three modules combine to form a square classroom space. Suspended ceiling panels of glued laminated timber are installed in the 3-metre-wide hallways between the room modules. The main beams span the classrooms in the direction of the long module

axes. The use of high-strength beech wood laminated veneer timber saves 8 centimetres of height compared to conventional spruce glued laminated timber. The modules were entirely prefabricated, including the interior visible surfaces, windows and technical services. Only the installation of the floor coverings and the mounting of the aluminium facade were performed on-site in order to avoid unwanted joints. Because of the well-planned emergency escape routes, a fire protection coating was required only in the stairwells. The recyclable aluminium facade will generate a profit after the building is dismantled. The modules can be reused until their timber is eventually reclaimed in a cascade utilisation process.

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1 Roof construction: waterproofing sheet 120-mm minimum thickness ­tapered insulation vapour-proofing layer 80-mm plywood 50-mm thermal insulation 25-mm wood wool acoustic panels 360/220-mm birchwood laminated veneer timber beam 2 Metal foil gutter 3 1 mm varnished aluminium sheet building wrap 120-mm thermal insulation 4 360/120-mm birchwood laminated veneer timber 5 Timber aluminium window with

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­anti-fall guard inset into the frame 6 100-mm plywood 50-mm sound insulation, ­perforated acoustic panels 7 Hallway floor construction: 2.5-mm linoleum 2≈ 16-mm particleboard 25-mm impact sound insulation panels 80-mm plywood 265-mm installation space 60-mm thermal insulation 25-mm wood wool acoustic panel 8 100/200-mm squared timber joist 9 Classroom floor construction: 2.5-mm linoleum 2≈ 16-mm particleboard

25-mm impact sound insulation panels 60 – 80-mm plywood 60-mm thermal insulation 25-mm wood wool acoustic panels 360/220-mm birchwood laminated veneer timber beams 10 Ground floor construction: 2.5-mm linoleum 2≈ 16-mm particleboard vapour-proofing sheet 25-mm impact sound insulation panels 80-mm plywood 100-mm thermal insulation 300-mm reinforced concrete ground slab

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Techno-Biotic Loop 4

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Steel and Timber Framework with Reed Thatching Wadden Sea Centre Ribe, DK 2017 Architects: Dorte Mandrup, Copenhagen

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In the flat landscape on Denmark’s west coast, topography and weather have combined to shape the traditional design of farmhouses. It is characterised by low, mostly U-shaped or four-sided closed layouts with a wind-protected inner courtyard. When the Wadden Sea Centre was refurbished and expanded, the shell of the ori­ginal 1990s building, which referenced the local construction typology but lacked ­visual appeal, was largely kept intact, a strategy that ensured the conservation of resources. The new exter­ ior cladding of narrow, grey-glazed black locust wood slats surrounds the double-leaf masonry and the steel structure of the ­original building, generating an entirely new appearance for the north- and west-facing building sections. The east wing gave way to a new construction, which was furnished from plinth to ridge with a thatched covering made of reeds sourced from two nearby bays. The new support structure was built from the closed-loop material steel, which allowed for the greatest possible freedom in the determination of form and the spatial partitioning of the interior, while the secondary framework is made of timber. In the roof, prefabricated timber panel elements were slotted in between the steel frames. The second new construction, which is likewise thatched in reed, is situated in front of the untouched southern wing of the compound and is built entirely of timber.

Techno-Biotic Loop

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1 Roof construction: 280-mm reed thatch fleece 73/38-mm battens 45/30-mm counter battens 9-mm building slab 45/45-mm battens, interspersed with thermal insulation 245/45-mm squared timbers, ­interspersed with thermal insulation vapour-proofing sheet 12-mm plywood 70/45-mm battens, interspersed with thermal insulation 18-mm plywood panels 12.5-mm plasterboard panels 46 mm acoustic panels with ­insulating coating 2 3≈ 12.5-mm plasterboard panels 70-mm galvanised steel fi profile support 3 HEB 220 steel profile column 4 UPE 120 steel profile girder 5 Exterior wall construction: 225-mm reed thatch fleece 60/30-mm battens 45/25-mm counter battens 9-mm building slab 245-mm thermal insulation vapour-proofing sheet 45-mm thermal insulation (installation zone) 15-mm plywood 12.5-mm plasterboard panels

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Built from the Hillside The Rauch House Schlins, AT 2008 Architects: Boltshauser Architekten, Zurich, with Martin Rauch, Schlins

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Eighty-five per cent of this residential and ­studio building was quite literally created from the hillside. The loam extracted from the excavated soil is used throughout the house, from foundation to roof. The manufacture of the loadbearing rammed earth walls is apparent in their exterior stratification. Clay brick strips, made from the same basic materials and fired on site, make up part of the rammed structure, emphasising its horizontal dimension and providing erosion protection in driving rain. Inside, the softer side of loam becomes visible. As a finegrained light-coloured plaster, it covers the internal insulation of renewable and compost­ able reed; polished smooth and with a silken gloss, it forms the surface of the terrazzo-like rammed earth floor. Depending on their spans, lintels are strengthened with steel beams or steel reinforcement, or poured from trass lime – a mixture of lime and volcanic trass powder – and ­covered with rammed earth. Doors and windows are mechanically joined to the rammed earth walls, and the joints are sealed with flax fibre and loam. The Rauch House is the result of focused material loop thinking: Instead of having to be disposed of as usual, the excavated ground is repurposed to furnish the building materials. In the end, after the technological elements have been removed, the house can revert once more to its original form – the hillside.

Locally Sourced Materials

1   1 Roof construction: 40-mm fired mud bricks 130 – 230-mm lava gravel fill multilayered waterproofing sheet 27-mm three-ply board 4≈ 50-mm reed thermal insulation matting vapour-proofing sheet 30 – 65-mm cork/loam mixture, sloped 180-mm (approx.) beam ceiling in dowelled beam ­construction filler timber 25-mm loam structural panels with 5-mm loam plaster   2 Exterior wall construction: 450-mm rammed earth 2≈ 50-mm reed thermal insulation matting 30-mm loam plaster reinforced with flax mesh 3 – 4-mm multiple layers of loam finishing coat   3 Oak wood windows, untreated outside and oiled inside, with insulated glass   4 27-mm spruce three-ply board reveals, smoothed with multiple layers of casein fill and waxed   5 100-mm rammed earth floor, waxed with hot plant-based wax levelling course 180-mm (approx.) beam ceiling in dowelled beam construction   6 280/120/30-mm fired mud brick erosion protection   7 300/150-mm ring beam, trass lime, steel-reinforced   8 400 – 600/300/40-mm fired mud brick splash zone protection   9 Multilayered waterproofing sheet 100-mm foam glass insulation 4-mm waterproofing sheet 10 Ground floor construction: 50-mm reed thermal insulation matting hollow core slab (Hourdi slab) 60/60-mm trass lime mortar and steel }-beam composite and 30-mm fired mud bricks 11 Ground slab construction: 100-mm sanded trass clay levelling course capillary-breaking gravel fill

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Regionally Sourced Natural Building ­Materials Residence Deitingen, CH 2009 Architects: spaceshop Architekten, Biel

The building client, a professional gardener, had the obvious aim of living self-sufficiently and in tune with the cycles of nature. The design of this house helps meet these criteria through the use of natural, locally sourced building materials. The character of the house is determined by its components, which are left untreated. The plinth is a masonry construction made from unmodified old tombstones and stones recovered from dismantled bridges and walls, bonded with trass lime mortar. The walls are of cob construction, using mater­ ials excavated from a building site in a neighbouring community. The mixture of loam and straw was layered without formwork and cut with spades to form the finished wall. A large roof overhang protects it from weather exposure. The lintels are strengthened with a reinforcement of bamboo cane and reed. The spruce for the support structure was sourced from the local forest. The large crosssections in the roof and floors are not made of glued laminated timber, but rather of reinforced, nailed and bolted beams. The roof and floor insulation was grown on neighbouring fields: untreated straw, compressed into bales, was packed between joists. The windows are sealed with hanks of “Seiden­ zopf” (“silken braid” – a backfill material made from recycled cotton). This measure is further supported by externally attached window frames that cover the joints.

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4 Solid larch wood windows, sealed with hanks of ­recycled cotton fibre and window joint tape timber construction with vapour barrier on inside 5 Ground floor construction: 120/27-mm solid spruce plank flooring, planed and waxed 60/60-mm battens 24-mm spruce subdeck vapour barrier 440/80-mm solid spruce joists, interspersed with 490/1,000/380-mm straw bale insulation 24-mm spruce decking 40/40-mm edge lath 6 150-mm natural stone masonry plinth 40/40-mm ventilation / ledger board 24-mm spruce sheathing 7 120/260-mm timber sill

1 Roof construction: 80-mm extensive green roof on recycled brick protection layer EPDM waterproofing sheet, loosely laid, clamped at roof edges separating sheet 28-mm spruce sheathing 100 –150-mm battens, rear ventilation, 24-mm spruce subdeck, 80/440-mm solid spruce rafters, interspersed with 490/1,000/380-mm straw bale insulation on cellulose panels vapour barrier 60/60-mm battens 120/20-mm spruce formwork, rough-sawn 2 800-mm cob wall, loam / straw 3 140/140-mm timber columns, encased in oiled paper

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Recycled Material from the Neighbourhood Villa Welpeloo Enschede, NL 2010 Architects: 2012 Architecten, Rotterdam

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About 60 % of the Villa Welpeloo’s new construction comprises reused and further used materials from the surrounding area, i.e. material left over from the demolition of a former ­textile factory in Enschede. The support structure is composed of steel beams that are screwed together, 90 % of which were taken from old textile machinery. Because the exact quality of the steel could no longer be determined, the structural designers assumed the worst possible quality in making their calculations. The facade is made from ­timber slats salvaged from the axles of large discarded cable drums. The wood was heat-treated before installation to improve its durability. Crimped horizontal lengths of sheet

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metal protect the end grain and partition the ­facade. The EPS thermal insulation in the ­exterior walls is sourced primarily from a ­demolished industrial building in the area. Because of the reuse and further use of existing materials and the short transportation routes, this building boasts significant savings in resources as well as carbon emissions compared to a conventional new building. Charting the nearby source locations of the used building materials for this project culminated in the “Harvest Map” (www.oogstkaart.nl). The website, originally developed by the ­architects for regionally procuring used mate­ rials in the Netherlands, is now operational throughout Europe.

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Maximised Recycling Fraction Upcycle House Nyborg, DK 2013 Architects: Lendager Group, Copenhagen

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The Upcycle House was developed as an experimental project by a Danish real estate company to investigate different approaches to sustainable construction. The building fully explores possibilities for the continued use of materials that have already completed one life cycle – not necessarily in the con­struction industry. As a result, the Upcycle House produces 86 % fewer CO2 emissions in its manufacture than a conventional building. A few of the project ideas will likely remain ­customised solutions (2, 4, 25). However, many of the recycled building materials are already in common use (6, 7, 11, 15, 19) or will conceivably find broad application

(3, 14, 24, 26). The recycling of plasterboard (20) has become widespread in Denmark. Used windows (13) or windows from defective lots (5) present challenges to design, since the sizing and customisation options are limited. The latter type were installed here with fixed glazing and with their frames concealed by the facade, so they cannot be opened. Insulated vents provide ventilation. Filled water canisters (1) replace the storage mass of solid building components. Although some of the materials used are not indefinitely loop-compatible, the extension of the lifetimes of already existing materials conserves resources.

Exploded view   1 Partition wall of used water canisters   2 Wall lining made from used bed sheets   3 Tiles of recycled waste glass   4 Kitchen floor from old champagne corks   5 Glass windows from defective lots   6 Corrugated sheet cladding, 95 % recycled aluminium   7 Recycled paper thermal insulation   8 45 ≈ 50-mm used wood battens   9 45 ≈ 195-mm used wood roof beams 10 Facade cladding from waste paper and plant resins 11 Ø 60-mm recycled aluminium columns 12 Terrace planks: composite of waste synthetics and wood 13 Used windows from a school refurbishment

14 Patio floor insulation of recycled foam glass granulate 15 Recycled paper facade insulation 16 Particleboard from waste wood 17 Kitchen countertop from used timber planks 18 Used kitchen cabinets, newly painted 19 Patio floor of used brick 20 Plasterboard of 25 % recycled gypsum 21 OSB panels from waste wood 22 45 ≈ 50-mm used wood battens 23 45 ≈ 95-mm used wood joists 24 Used 40-foot shipping container 25 Floor insulation from shredded EPS rigid foam waste 26 Plinth from the boards of an ice skating rink 27 Footings of used screw piles

Recycled

Recycled Glass Facade Folkwang Museum Building Extension Essen, DE 2010 Architects: David Chipperfield Architects Berlin

Horizontal section Scale 1:20 1 Exterior wall construction: 20-mm glass ceramic facade panels, supported on aluminium angles, anchored from the rear by ­powder-coated aluminium compression-suction ­anchors 80-mm rear ventilation 120-mm thermal insulation 300-mm reinforced concrete high-load steel sheet support profiles 40-mm thermal insulation 18-mm OSB panels 12.5-mm plasterboard, rendered and painted 2 15 mm fixed ESG white glazing, clamped into 20/120-mm glass ceramic pilaster / capping strip ­together with facade panels, on custom aluminium profile mounting bar 3 Aluminium windows, matte powder-coated, insulated 4 Aluminium posts, matte powder-coated 5 Aluminium windows, matte powder-coated, with insulating glass

The new extension of the Folkwang Museum complements the historically listed older building from the 1960s. The design assimilates the existing structure through the addition of further pavilions around interior green courtyards. With the newly built extension, the ­existing building also gains an inviting exterior staircase. The shining glacier-green pavilions rest on a base course clad with artificial stone. The facade material of the pavilions is a product made out of recycled waste glass shards that have been sintered into panels. This “glass ceramic” has a very hard, easy-to-clean surface with a great depth effect, which makes

its appearance vary widely with the ambient light. The detachable fastening of the facade panels is achieved by supporting them on ­concealed brackets and securing them with compression-suction anchors. The placement of the large openings set into the facade panel grid emphasises the abstract cubic appearance of the buildings. Set flush with the facade, the openings are executed as a double facade of aluminium profiles with a fabric sun protection panel between them. Capping strips also made from glass ceramic section the facade in a pilaster-like manner and connect opaque and transparent surfaces across storeys.

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Reused Brick Building Shell Cultural Institute, Formerly Hombroich Rocket Station Neuss, DE 2009 Architects: Alvaro Siza, Porto, with Finsterwalder Architekten, Stephanskirchen

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With a space-shaping gesture, the structure expands into the surrounding area of a former rocket station, which has been converted into a cultural campus extension of the Insel Hombroich Museum. The exhibition rooms are situated in the centre of the building, which is dedicated to the sculptor Erwin Heerich. The view from these rooms is directed across the interior courtyard and out into the landscape. The brick of the shell references the architecture “sculptures” by Heerich on the neighbouring museum island, which are made of the same material: bricks sourced from dismantled buildings from the surrounding area and the nearby Netherlands. For this location, in fact, the recycled bricks were actually less expensive than new bricks with a comparable aesthetic haptic quality. The roof construction comprises spruce KVH structural timbers, reinforced from below by 20 millimetres of solid oak. Thanks to its dimensions, the high quality of its materials and its ease of disassembly, the construction makes subsequent reutilisation possible. The roof is conceived as a ventilated cold roof, thus avoiding the critical problem of ­condensation. The limestone tiles cladding the interior surfaces of the toilet area can be separated by type at demolition and reintroduced into the limestone material loop.

Recycled

A Tradition of Reusing Structural Components History Museum Ningbo, CN 2010 Architects: Amateur Architecture Studio Wang Shu / Lu Wenyu, Hangzhou

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With expressive power, the museum occupies a broad, urban expanse in the form of a colossal stone sculpture. Resting on a rectangular plinth, the structure splits up into upwardstriving, sharp-edged volumes. The openings are compositionally placed and allow scant conclusions to be drawn about the functions or floors beyond. Subordinating itself to the “usable sculpture” motif, the shell material extends across facades and pitched roofs. Although the building presents itself as abstract when seen from afar, up close it references a more human scale. Large portions of the facade consist of well-known elements such as ­roofing tiles, masonry bricks or hewn stone. The materials recovered from demolition, of which there are about 20 different kinds, appear to be interwoven with one another and alternate like pieces of a collage with haptic, rough-faced exposed concrete surfaces and wooden window shutters. The reutilisation of used structural components can be traced back to a regional tradition, still honoured in the present day in reconstruction work following natural disasters. In adopting the tradition here, however, the architects are reminding visitors of the man-made destruction of the dozens of surrounding villages from which the materials were taken – villages that were forced to give way to the rapidly expanding city.

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Authors Annette Hillebrandt Born in Essen in 1963 Univ.- Prof. Dipl.-Ing. Architect BDA (German Architects’ Association) 1982–1989 studied architecture at the Technische ­Universität Dortmund 1989 –1994 employed as an architect Since 1994 self-employed architect in Cologne 1994– 2001 Hillebrandt + Schulz-Architektur, Cologne 2001– 2010 hillebrandt-architektur, Cologne Since 2010 msah m. schneider a. hillebrandt architektur, Cologne 2001– 2003 Professor of Structure, Design and Construction in Existing Buildings, FH Kaiserslautern 2003 – 2013 Professor of Building Construction, Münster School of Architecture Since 1992 member of Architektenkammer NRW ­(Chamber of Architects North Rhine-Westphalia) Since1996 active as jury member in architecture ­competitions Since 2001 member of various design committees Since 2013 Professor of Building Construction, Design and Material Studies, Bergische Universität Wuppertal, with a research focus on Loop Potential in Architecture 2009 founder of www.material-bibliothek.de 2010 appointed to panel of experts on “Dismantling and Recycling Compatibility” of the DGNB (German Sustainable Building Council) 2011 awarded German Facade Award for rear-ventilated facades Since 2014 member of the DGNB 2015 Urban Mining Award 2016 Founding member of IRBau (Initiative for ResourceConserving Building ) 2016 co-founder of the Urban Mining Student Award 2016 founding member of IRBau Initiative Ressourcen­ schonende Bauwirtschaft (Initiative for Resource-­ Conserving Building), renamed re!source Stiftung e. V. in 2019 2017 founder of www.urban-mining-design.de Petra Riegler-Floors Born in Saarbrücken in 1975 Dipl.-Ing. Architect 1994 –1995 Diplôme de Culture française, Sorbonne, Paris 1995 –1997 studied biology at the RWTH Aachen 1997– 2003 studied architecture at the RWTH Aachen and at ETSAV Barcelona 2004 – 2007 employee and project leader at synn architekten, Vienna 2007– 2008 research associate at the Faculty of Residential Construction and Design, Prof. Wim van den Bergh, RWTH Aachen 2007– 2011 employee and project leader at msah architektur, Cologne Since 2011 self-employed architect in Cologne Since 2013 research associate at the Faculty of Building Construction, Design and Material Studies, Prof. Annette Hillebrandt, Bergische Universität Wuppertal 2003 Euregional Prize for Architecture EAP, First Place 2003 Masterclass Steel, Archiprix International, Berlage Institut Rotterdam Since 2010 member of the Architektenkammer NRW (Chamber of Architects North Rhine-Westphalia) Anja Rosen Born in Bielefeld in 1970 M.A. Architect 1986 –1998 training as a banker, followed by employment and parental leave 1999 – 2009 employed at Hartmann-Walk Building Biology and Ecology, Warendorf 2005 – 2012 studied architecture at the Münster School of Architecture 2009 – 2011 research associate at the Münster School of Architecture; development of www.material-bibliothek.de 2012 – 2013 employed at msah architektur, Cologne

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Since 2009 employed at the agn group, agn Niederberghaus & Partner, Ibbenbüren Since 2013 DGNB auditor and certified expert for ­sustainable building (SHB) Since 2013 lecturer at the Faculty of Building Con­ struction, Design and Material Studies, Prof. Annette Hillebrandt, Bergische Universität Wuppertal Since 2010 member of the DGNB Since 2014 doctoral studies at the Bergische Universität Wuppertal in the Faculty of Building Construction, Design and Material Studies, Prof. Annette Hillebrandt, dissertation on the development of a methodology for the quantitative assessment of the loop potential of buildings in new construction design Since 2016 member of the Architektenkammer NRW (Chamber of Architects North Rhine-Westphalia) 2009 recognition award from the Arbeitsgemeinschaft Industriebau (AGI), Second Place 2010 university award 2009/10, FH Münster 2014 appointed to panel of experts on “Dismantling and Recycling Compatibility” of the DGNB (German Sustainable Building Council) 2016 co-founder of the Urban Mining Student Award 2016 founding member of IRBau Initiative Ressourcen­ schonende Bauwirtschaft (Initiative for Resource-­ Conserving Building), renamed re!source Stiftung e. V. in 2019 Johanna-Katharina Seggewies Born in Münster in 1988 M.A. M.Sc. 2009 – 2012 studied architecture at the Bergische Uni­ versität Wuppertal, B.Sc. 2012 – 2014 studied architecture at the Kunstakademie Düsseldorf, M.A. degree in architecture 2014– 2016 studied architecture at the Bergische Universität Wuppertal, M.Sc. 2013 – 2016 employed at blumberg + schürg architekten – ingenieure, Wuppertal 2015 – 2016 research assistant at the Faculty of Design and Building Studies, Prof. Susanne Gross, Bergische Universität Wuppertal Since 2016 research associate at the Faculty of Building Construction, Design and Material Studies, Prof. Annette Hillebrandt, Bergische Universität Wuppertal

Authors of the Technical Contributions Günther Bachmann Prof. Dr.-Ing. 1974–1978 studied landscape design 1983 – 2001 worked at the German Federal Environmental Agency: responsible for the Federal Soil Protection Act Since 2001 Secretary General of the Berlin office of the Council for Sustainable Development Chairman of the jury for the German Sustainability Award as well as the Next Economy Awards Since 2012 honorary professor at the Leuphana University of Lüneburg Active in scientific advisory panels, foundations and ­international networks Markus Binder Born in 1970 Prof. Dipl.-Ing. Architect Studied architecture at the University of Stuttgart Studied building physics at the Hochschule für Technik Stuttgart 1998 – 2011 project-leading architect at architecture offices in the greater Stuttgart area 2007– 2011 teaching associate at the Hochschule für Technik Stuttgart, Dept. of Building Physics 2009 – 2011 university teaching position in building ­physics at the Staatliche Akademie der Bildenden ­Künste Stuttgart 2011 visiting professor for Building Construction and Design, specifically climate-conscious architecture, at the Hochschule für Technik Stuttgart Since 2012 Professor of Integrated Building Technology at the Hochschule für Technik Stuttgart Since 2013 partner at CAPE climate architecture physics

energy, Esslingen / Schwäbisch Hall Since 2017 Dean of Bachelor Studies in Architecture and Associate Dean of the Faculty of Architecture and Design at the Hochschule für Technik Stuttgart Manfred Helmus Born in Leverkusen in 1959 Univ.-Prof. Dr.-Ing. 1979 – 1985 studied civil engineering in Dortmund and Stuttgart 1989 earned doctorate at the Technische Hochschule Darmstadt under Prof. Dr.-Ing. G. König Since 1992 Professor of Construction Management Since 1999 founder and chairman of the V.S.G.K. e. V. (Association of German Safety and Health Coordinators) Since 2002 director of the AHO expert commission on construction site ordinance Since 2003 university Professor of Construction Management at the Bergische Universität Wuppertal 2015 foundation of the BIM Institute at the Bergische ­Universität Wuppertal (location for interdisciplinary ­specialist research in the field of Building Information Modelling, where processes are analysed and documented, concepts are developed, optimised and implemented in pilot projects) Recipient of the Konrad Zuse Medal from the Zentralverband des Deutschen Baugewerbes (Central Federation of the German Construction Industry) for outstanding achievements in construction informatics Member of the executive committee “Council of Building Coordinators” in the Federal Ministry of Labour and Social Affairs Member of the “personal protective gear (PSA)” standards committee of the “RFID in PSA” working group of the DIN Member of the BIM working group of the reform com­ mission “Major Construction Projects” of the Federal Ministry of the Interior, Building and Community Holger Hoffmann Born in Gütersloh in 1974 Univ.- Prof. Dipl.-Ing. Architect BDA (German Architects’ Association) 1993 –1995 apprenticeship as bricklayer in Wiedenbrück 1995 – 2000 studied architecture at the FH Münster 2000 – 2001 employed as an architect at Bolles + Wilson, Münster 2001– 2004 postgraduate fellowship through the Konrad Adenauer Foundation 2001– 2004 Städelschule Frankfurt, degree with distinction 2005 Taut Prize of the Bundesarchitektenkammer ­(Federal Chamber of Architects) 2002 – 2008 employed as an architect at UNStudio, Amsterdam 2007– 2011 Professor of Digital Construction and Design at the Hochschule Trier 2015 – 2016 Visiting professor at the Städelschule in Frankfurt am Main Since 2009 one fine day: office for architectural design, Düsseldorf Since 2011 Professor of Representational Methodology and Design at the Bergische Universität Wuppertal Thomas Maximilian Kasper Born in Vienna in 1976 Dipl.-Ing. Mag. jur.  1994– 2004 studied land and water management at the University of Natural Resources and Life Sciences, Vienna; Thesis at Griffith University, School for Environmental Engineering; Brisbane, Australia 2000 – 2002 employed at the civil engineering firm DI Vinzenz Trugina, Trugina & Partner GmbH, Laxenburg Since 2004 at PORR Umwelttechnik GmbH, currently master builder, director of process development 2008 – 2013 studied law at Johannes Kepler University Linz 2013 founded Büro Kasper, an engineering firm for land and water management Since 2014 member of the board of directors of the Austrian Güteschutzverband (GSV) Recycling-Baustoffe (Quality Assurance Association for Recycled Building Materials)

Since 2015 vice president of the European Quality Association for Recycling (EQAR) Since 2016 president of the Baustoff-Recycling Verband (BRV) (Construction Material Recycling Association) Member of CEN (European Committee for Standardization) Expert and staff member at the Austrian Standards Institute Winner of the 2004 FCP Award for Sustainable Development in Civil Engineering Holger Kesting Born in Münster in 1975 Dipl.-Ing. 1999 – 2009 studied civil engineering at the Bergische Universität Wuppertal 2009 – 2015 employee and deputy general manager at Kullmann Bau-Unternehmen GmbH, Haan Since 2015 estimator at Kullmann Bau-Unternehmen GmbH, Haan Since 2015 research associate in the academic and research field of Construction Operations and Industry at the Bergische Universität Wuppertal Since 2016 lecturer at the Bergische Universität Wuppertal Since 2017 research associate at the Faculty of Materials in Construction, Univ.- Prof. Dr.-Ing. Steffen Anders at the Bergische Universität Wuppertal Since 2017 lecturer at the IHK Essen Member of the VDI (Association of German Engineers) – Arbeitskreis 2552 Blatt 9 Building Information Modeling – Klassifizierungen Member of the audit committee for the training of construction management assistants in architecture and engineering, IHK Essen Since 2016 active as an author Thomas Matthias Romm Born in Eschweiler in 1965 Dipl.-Ing. Architect Studied architecture at the TU Wien and the TU Berlin Since 1986 architecture and construction site practical experience concurrent with university studies 2000 thesis on recycling-compatible construction 2000 – 2003 managing director for building physics, A-NULL EDV GmbH (energy consumption analysis in BIM) 2003 – 2013 collaboration with Dr. Robert Korab, Büro für Städtebau (Office of Urban Construction); research and project development 2007– 2011 residential construction and research as independent architect Since 2011 large-scale urban mining projects in bidding consortium with Dr. Ronald Mischek ZT 2013 nominated for Austrian State Prize for Engineering Consulting Since 2015 state-licensed architect/engineer, forschen planen bauen ZT, Vienna Since 2017 lecturer at IKA, Akademie der bildenden ­Künste, Vienna 2015 co-founder of www.BauKarussell.at, employment and recycling economy 2018 environmental award from the City of Vienna for BauKarussell Michael Wengert Dipl.-Ing. 1997– 2002 studied civil engineering, specialising in building physics / materials, design and construction and building construction management Since 2008 employed ati Pfeil & Koch ingenieurgesell­ schaft Since 2012 power of attorney Since 2016 general commercial power of representation Since 2006 energy consultant BAFA Since 2008 member of the Ingenieurkammer (Chamber of Engineers) Baden-Württemberg Since 2010 certified Passive House designer Tobias Edelmann B. Eng. 2013 – 2018 studied building physics at the HfT Stuttgart, specialising in thermal building physics and energy technology Since 2018 employed at Pfeil & Koch ingenieurgesellschaft

Project Participants Musée Soulages in Rodez (FR) Musée Soulages in Rodez (FR) Architects: RCR Arquitectes, Olot Project team: G. Trégouët (project management) Structural engineering: Passelac & Roques, Narbonne Lausward Power Plant in Düsseldorf (DE) Architects: kadawittfeldarchitektur, Aachen Project team: Burkhard Floors (project management), Hagen Urban, Mathias Garanin, Jonas Kröber, Christoph Katzer, David Baros, Hanns Luh, Florian Graus, Marc Bennemann, Andreas Horsky, Vera Huhn, Astrid Dierkes, Julika Metz Structural engineering: Bollinger + Grohmann Ingenieure, Frankfurt am Main Training Centre in Gordola (CH) Architects: Durisch + Nolli, Lugano Project team: Thomas Schlichting, Dario Locher, Birgit Schwarz Structural engineering: Jürg Buchli, Haldenstein, Tecnoprogetti, Camorino Documentation Centre in Hinzert (DE) Architects: Wandel Hoefer Lorch + Hirsch, Saarbrücken Project team: Christine Biesel, Alexander Keuper Structural engineering: Schweitzer Ingenieure, ­Saarbrücken The Nelson-Atkins Museum of Art in Kansas City (US) Architects: Steven Holl Architects, New York Project team: Richard Tobias (project management), ­Martin Cox (project management), Gabriela BarmanKraemer, Matthias Blass, Molly Blieden, Elsa Chryssochoides, Robert Edmonds, Simone Giostra, Annette Goderbauer, Mimi Hoang, Makram el-Kadi, Edward ­Lalonde, Li Hu, Justin Korhammer, Linda Lee, Fabian Llonch, Stephen O’Dell, Susi Sanchez, Irene Vogt, Urs Vogt, Christian Wassmann Local architects: Berkebile Nelson Immenschuh ­McDowell Architects, Kansas City Structural engineering: Guy Nordenson & Associates, New York Window Factory in Hagendorn (CH) Architects: Graber & Steiger, Lucerne Project team: Urs Schmid (project management), ­Roland Stutz (project management), David Zimmermann Structural engineering: Locher AG, Zurich Community Centre in St. Gerold (AT) Architects: Cukrowicz Nachbaur Architekten, Bregenz Project team: Stefan Abbrederis (project management), Michael Abt, Christian Schmölz Structural engineering: M+G Ingenieure, Feldkirch Wood Innovation and Design Centre in Prince George (CA) Architects: Michael Green Architecture, Vancouver Project team: Mingyuk Chen, Carla Smith, Seng Tsoi, Kristalee Berger, Alfonso Bonilla, Jordan van Dijk, ­Guadalupe Font, Adrienne Gibbs, Jacqueline Green, Asher deGroot, Soo Han, Kristen Jamieson, Vuk KrcmarGrkavac, Alexander Kobald, Sindhu Mahadevan, Maria Mora Structural engineering: Equilibrium Consulting, Vancouver

Residence in Vorarlberg (AT) Architects: Georg Bechter Architektur + Design, ­Langenegg Project team: Anna Höss Structural engineering: Eric Leitner, Schröcken Office Building in St. Johann in Tyrol (AT) Architects: architekturwerkstatt Bruno Moser, Breitenbach am Inn Project team: Bruno Moser, Florian Schmid, Thomas Schiegl Structural engineering: dibral, Alfred R. Brunnsteiner, ­Natters European School in Frankfurt am Main (DE) Architects: NKBAK, Frankfurt am Main Project team: Simon Bielmeier, Larissa Heller Structural engineering: Bollinger + Grohmann Ingenieure, Frankfurt am Main merz kley partner, Dornbirn Wadden Sea Centre in Ribe (DK) Architects: Dorte Mandrup, Copenhagen Project team: Kasper Pilemand (project management) Structural engineering: Anders Christensen, Birkerød The Rauch House in Schlins (AT) Architects: Planungsgemeinschaft Roger Boltshauser, Zurich, with Martin Rauch, Schlins Collaborators: Thomas Kamm (project management), ­Ariane Wilson, Andreas Skambas Structural engineering: Josef Tomaselli, Bludesch Residence in Deitlingen (CH) Architects: spaceshop Architekten, Biel Project team: Raphaël Oehler, Beno Aeschlimann, Stefan Hess, Reto Mosimann Timber structural engineering: TS Holzbauplanung, ­Ersigen Loam construction consulting: Ralph Künzler, Winterthur Villa Welpeloo in Enschede (NL) Architects: 2012 Architecten, Rotterdam Project team: John Bosma, Frank Feder Structural engineering: Nico Plukkel Bouwkundig, Haarlem Upcycle House in Nyborg (DK) Architects: Lendager Group, Copenhagen Collaborators: Anders Lendager (project management), Rune Sjöstedt Sode, Christoffer Carlsen, Jenny Haraldsdottir, Anna Zobe Structural engineering: MOE Rådgivende Ingeniører, ­Copenhagen Folkwang Museum Building Extension in Essen (DE) Architects: David Chipperfield Architects, Berlin Project team: Ulrike Eberhardt (project management), Eberhard Veit (project management), Markus Bauer, ­Florian Dierschedl, Annette Flohrschütz, Gesche Gerber, Christian Helfrich, Barbara Koller, Nicolas Kulemeyer, Dalia Liksaite, Marcus Mathias, Peter von Matuschka, ­Sebastian von Oppen, Ilona Priwitzer, Mariska Rohde, Franziska Rusch, Antonia Schlegel, Marika Schmidt, Thomas Schöpf, Gunda Schulz, Manuel Seebass, Robert Westphal Executing architects: PLAN FORWARD, Stuttgart Structural engineering: Pühl und Becker, Essen

Aktivhaus Residential Estate in Winnenden (DE) Architects: Werner Sobek, Stuttgart Project team: Stephanie Fiederer, Thorsten Klaus, Frank Peiser, Alen Masic Structural engineering: Werner Sobek, Stuttgart

Cultural Institute, Formerly Hombroich Rocket Station near Neuss (DE) Architects: Alvaro Siza, Porto, with Finsterwalder Archi­ tekten, Stephanskirchen Project team: Burkhard Damm, José Diniz Santos, ­Matthias Heskamp, Heinz Kirschner, Steffi Zucker Structural engineering: Horst Kappauf, Monheim am Rhein

Holiday Home in Kumrovec (HR) Architects: Proarh, Zagreb Project team: Davor Mateković (project management), Oskar Rajko Structural engineering: Branko Galić, Zagreb

History Museum in Ningbo (CN) Architects: Amateur Architecture Studio, Hangzhou Wang Shu, Lu Wenyu Project team: Song Shuhua, Jiang Weihua, Chen Lichao Structural engineering: Shentu Tuanbing, Hangzhou

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Glossary aerogel Highly porous solid in which up to 99.98 % of the volume is taken up by the pore cavities. The most common aerogels are silicate-based. In principle, all metal oxides, ­polymers and other materials can be used as a base ­substance for the synthesis of an aerogel using the solgel process. aggregate Sand, gravel or crushed stone, etc. used in the manufacture of mortar and concrete. anthropogenic resource repositories Man-made forms of storage created to accommodate ­resources that have been extracted from their natural ­locations. These include infrastructure, buildings, goods, products and waste materials. anthropocene From the Greek anthropos = human and kainos = new. A term used in science for the new (current) geological age, in which humanity has become one of the most ­significant factors impacting biological, geological and atmospheric processes on planet Earth. A / V ratio Ratio of surface area A and volume V of a geometric ­object. BES 6001 A standard developed by the British Building Research Establishment (BRE) for the responsible sourcing of raw materials for use in building materials and products. The standard establishes a framework for the organisational governance, supply chain management and environmental and social aspects that must be addressed so that businesses and organisations can provide evidence that an effective ongoing system for responsible sourcing ­exists for a given product. biocides Substances and products that are used to combat pests or vermin such as insects, mice and rats, but also algae, fungi or bacteria. Because of the potential hazards they pose to the environment and the health of humans and animals, biocides must undergo an en­ vironmental risk analysis and be certified before being used in the EU. biosphere The volume of a planetary body (and Earth in particular) occupied by living organisms. biosynthetics, bio-based synthetics or biopolymers Synthetic materials that are based on renewable primary resources. Starting materials are primarily starch and ­cellulose, biopolymers of sugars. In comparison to fossilderived synthetics, in general biosynthetics represent a 30 –70 % reduction in CO2 emissions. biotic / abiotic factors Biotic factors are influences on an organism that originate from other living organisms. They can come from organisms of the same type or from different types. The abiotic part of an ecosystem is the non-living component. Abiotic factors include all environmental influences in which living organisms have no apparent role, such as radiation, temperature, carbon dioxide, oxygen, nutrients, wind and any impacts resulting from these parameters (e.g. corrosion), mechanical influences, ground structure, chemical compositions of the air and soil. biotic / abiotic substances / building materials Biotic substances are all those of animal or plant ­origin that have not been transformed into fossil or ­mineral ­materials, e.g. timber or cork (renewable ­resources).

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The abiotic materials include all those of a “non-living” ­nature that are therefore non-renewable, e.g. metallic, fossil or mineral resources. bonding agents, thermosetting / thermoplastic Synthetic, polymer-based bonding agents. Polymers are created when small molecules (monomers) bond chemic­ ally to form larger molecules. Thermoplastics are uncured polymers. At temperatures above about 80 °C, previously hardened thermoplastics begin to melt and become elastic; with further temperature increases they achieve plasticity. Thermoplastic ­resins harden through the evaporation of solvents or water. Thermosetting polymers, once cured, cannot be melted again. In contrast to thermoplastics, heating thermosetting polymers will not result in plasticity. buffer space Unheated intermediate space between the outdoors and heated interior rooms (e.g. attic, conservatory, cellar or stairwell). Building Information Modelling (BIM) A 3D-model-based process that provides architects, ­engineers, building clients and facility managers with ­information and tools for the design, construction, ­maintenance and administration of buildings and infrastructure. by-product Term used to describe everything that is generated during the manufacture of a (main) product, including occasional unwanted materials. Industrial by-products include, for example, carbon dioxide in the energy industry and various slags in branches of the metal industry and blast furnace production. cascade utilisation Successive multi-step material and, where applicable, eventual energetic reclamation processes for the utilisation of primary resources such as timber (e.g. structural timber – plywood – energetic reclamation). cash value Financial term describing the value that future expend­ itures have in the present, assuming a particular interest yield. The determination of cash values allows the comparison of expenditures that will occur at different times. To calculate the cash value of a cash flow, the individual receipts and disbursements are discounted by a given ­interest rate. Discounting takes into account that, the further the due date for a payment is delayed, the smaller the present cash value of the payment becomes for both the debtor and the creditor. circular economy An economic model in which the primary resources used in a construction or product are supposed to be ­reintroduced into the production process after the original object life cycle has ended. This requires the ­existence of closed product-recycling loops. closed-loop material * A material of which almost 100 % can be kept in a re-­ utilisation loop without loss of quality. This is true, for ­example, of many metals. As a renewable resource, ­timber can be made into a 100 % closed-loop material if its cultivation is converted from conventional to ­certified sustainable, thus guaranteeing that timber will never be harvested to a greater degree than can be regrown. closed-loop potential * The potential of a construction or of a product to generate closed loops. The closed-loop potential of a construction is the percentage of its materials and components that can be kept in a closed loop without loss of quality as ­defined by predetermined criteria.

confidence interval Range of values within which the true value of a given ­parameter is assumed to lie with a stated probability (confidence level). The interval is based on the distri­ bution generated by an infinite repetition of a random ­experiment. A frequently employed confidence level is 95 %, which means that at least 95 % of the confidence intervals calculated on the basis of measured values will include the true mean value of the distribution in question. confidence limit Mathematically/statistically determined interval bound­ ary. Measured or functional random sample values that fall beyond this limit are assumed to be statistically significant (have a non-random probability). The confidence interval is bounded by upper and lower confidence limits. construction and demolition wastes Collective term for the mineral and non-mineral wastes that are generated during the construction and demolition of buildings. Construction and demolition wastes are classified in Chapter 17 of the Waste Catalogue Or­ dinance (AVV). construction site waste Primarily non-mineral mixtures of recyclable and non-­ recyclable wastes generated during construction ­activities. corrosivity The characteristic ability of a corrosive medium (a liquid or gaseous substance) to eat away at or erode material in a given situation. degradation In the context of photovoltaic modules, this term refers to their decrease in efficiency over time. downcycling A substance that can be recovered from processing only in a lesser-quality form is subject to “downcycling”. This category includes substances such as concrete, ­materially reclaimable timber (e.g. unweathered timber and waste woods that have already been reused), and mono-material synthetics, whose utilisation in recycling processes is always associated with loss in quality (∫ recycling, ∫ upcycling). Example: The use of crushed brick as a plant substrate. durability classes DIN EN 350 establishes the criteria by which the resistance of timber and timber products against biological ­attack are tested. The standard classifies the durability of wood with respect to fungi, beetle infestations, termites and marine organisms and subsequently cate­ gorises a large selection of timber varieties by their ­durability. eco-effectiveness Term used by German chemist Michael Braungart and American architect William McDonough in their 2002 book Cradle to Cradle (C2C). They used the term in contrast to eco-balance (∫ Life Cycle Assessment) and ∫ ecoefficiency. According to Braungart and McDonough, products are eco-effective if they can be kept either within a biological loop as biological nutrients or continually within a technological loop as a technological material. eco-efficiency The ratio of the economic value of a product and the ­impact that its manufacturing process has on the envir­ onment, measured in an appropriate unit. The term was introduced in 1991 by the Business Council for Sustain­ able Development, now the World Business Council for Sustainable Development – WBCSD. The motivation for

this was the goal of bringing the negative ecological ­effects and resource intensity over the entire life cycle of a product to a level that was compatible with the Earth’s capacity limits. efficiency Level of performance and economic feasibility, from the Latin efficere = effect, bring about, do. It is an evaluation criterion which can be used to determine whether a measure can be implemented to achieve a specified goal under given conditions (e.g. in an economically ­viable manner). electrodynamic fragmentation ∫ fragmentation electrohydraulic fragmentation ∫ fragmentation EMAS (Eco-Management and Audit Scheme) A joint system developed by the EU from environmental management and environmental auditing programmes for businesses and organisations for the purpose of ­improving their ecological efficiency. End of Life, EoL scenario In the context of product life cycles, this term describes the end phase of the existence of a product (after the manufacture and use phases). The EoL scenario lists the possible options available to a product after its use phase, ranging from recycling to disposal. Environmental Product Declarations (EPD) EPDs describe building materials, products or components in terms of their environmental impacts based on life cycle assessments as well as their functional and technical characteristics. The information is quan­ titative, objective and verified and refers to the entire life cycle of the building product. EPDs provide an ­important foundation for the sustainability assessment of buildings. fossil substances / building materials substances / building materials consisting of the remains of animals and plants from earlier geological ages. These include, for example, oil-based materials such as bitumen or plastics. fraction ∫ waste fraction fragmentation, electrodynamic or electrohydraulic Process for the separation of composite materials. The electrodynamic process allows substances such as waste concrete, combustion slag and carbon-fibre-­ reinforced synthetics to be separated, based on the ­principle that ultrashort (< 500 nsec) underwater impulses selectively fragment solids because the electrical ­discharge tends to occur along phase boundaries. The technology has already been implemented on a large scale, for example in the breakup of hyperpure silicone for the solar cell industry, or for the extraction of lithium from the surrounding rock matrix. The electrohydraulic process is suitable for the release of metallic inclusions from mineral slags, the dissociation of fibre and laminate materials (e.g. carbon-fibre-re­ inforced plastics – CRP, fibreglass, glass laminate foils). It is based on shockwaves produced by spark dis­ charges and transmitted to the material through a fluid. Short but very powerful mechanical shocks isolate the weak points of the material and separate it at ­macroscopic (clamped, glued, screwed) joints or at ­microscopic (aggregate or phase) boundaries. FSC (Forest Stewardship Council) An international not-for-profit organisation founded in 1993 that has defined a worldwide basic standard

for ­responsible forest management. The label FSC on timber and timber products certifies that these are not ­associated with destructive exploitation or environmental degradation, but are sourced from sustainably managed forests.

lignin Structural substance found in timber which, together with cellulose and other substances, forms the cell walls of wood. The decomposition of lignin through UV radiation causes the brown colouration of wood.

further use If a used building product can be used again for a ­purpose other than its originally intended function at a lower-quality level, it is considered to be of “further use”. All materials that are categorised as reusable can, of course, also be used for a different purpose, possibly at a lower-quality level (∫ downcycling). Example: The reuse of intact masonry bricks as lawn edging.

loop potential * A quantity which provides information about the component fraction of a material or construction that allows for a constant-value recycling or reduced-quality downcycling or cascade utilisation. The loop potential of a construction thus extends beyond the closed-loop portion to include resources and building materials that, according to predefined criteria, can undergo either a material reutilisation with loss in quality (downcycling) or an energetic reclamation process.

glass ash Quenched power plant ash used as an alternative to crushed stone or gravel, for example as a levelling course or capillary-breaking layer under the ground slab, for drainage or as a pavement sub-base. grey energy In construction, a term used to describe the energy that is required in the erection of a building. Grey energy ­includes the energy needed to source, manufacture and process building materials, to transport people, ­machines, building components and materials to the ­construction site, to install the building components, and to dispose of waste.

maintenance Combination of all the technical and administrative as well as management measures that must be taken during the life cycle of a unit in order to maintain or re-­ establish the functionality for which the unit was installed. ­According to DIN 31 051, maintenance encompasses all the regular inspections, care and servicing of an existing object. Material Cycle Status * The Material Cycle Status encompasses the three cat­ egories Material Recycling Content – MRC, Material Loop Potential – MLP and Material End of Life – MEoL.

ideal residual cross-section The effective cross-section of timber members that ­remains after burn depth and the effects of corner smoothing and splitting have been taken into ­account.

Material End of Life (MEoL) * The current status of the post-use utilisation or disposal options for a material: the description of the utilisation and /or disposal fractions of a building material at the end of its usage phase.

inert material landfill Inert = sluggish, immovable. Inert materials are those that are chemically and biologically stable without further processing and can be disposed of in class 0 landfills. (∫ landfill)

material flow management Targeted, responsible, holistic and efficient management of material streams as seen from ecological, economic and social perspectives. The management of material flows in the waste industry serves to analyse, assess and optimise waste systems.

landfarming The depositing of demolition and soil materials – after breaking them up and adding nutrients – to large flat ground surfaces. landfill A disposal site for wastes, classified according to the type of waste deposited: Class 0: For the disposal of inert wastes (minimally ­contaminated mineral wastes) Class I: For the disposal of non-hazardous wastes with a very small organic component Class II: For the disposal of non-hazardous wastes with a small organic component Class III: For the disposal of hazardous wastes Class IV: For the disposal of mining wastes Life Cycle Assessment Procedure for the compilation and assessment of the ­balance of input and output flows and the potential ­environmental impacts of a product system throughout its life cycle. The inputs are the product, resource and ­energy flows that enter into a process module. The outputs are the product, resource and energy flows that are generated by a process module. The life cycle assessment for buildings is governed by DIN EN 15 978 and ISO 14 044. Life Cycle Costs The costs incurred by a product or service over the course of its entire lifetime. ISO 15 686-5 subdivides the Life Cycle Costs (LCCs) of buildings into categories for construction, occupancy, maintenance and “end of life”.

Material Loop Potential (MLP) * Possible future percentage of recycled materials in a product, assuming the maximum use of secondary raw ­materials in the manufacture of the product. Material Recycling Content (MRC) * The current percentage of recycled materials in a product (∫ recycling content). metallic substances / building materials Substances / building materials that belong to the chem­ ical group of metals and their alloys, in which the extension into the semi-metals is taken to be continuous. The cohesion in metals is based on metallic bonds. The bond is also the source of properties such as electrical conductivity, thermal conductivity, ductility and mirror ­finishes. Metallic materials include, e.g. zinc and steel. mineral substances / building materials Inorganic, non-metallic substances / building materials of crystalline composition, e.g. gravel or brick. moisture storage capacity The ability of a building material to absorb water vapour, store it, and release it over a period of time. obsolescence From the Latin obsolescere = to wear out, become old, lose value. The term describes the naturally or artificially induced ageing or aged condition of products or bodies of knowledge. Goods or usable objects decline in user acceptance before the end of their usage phase (as ­determined by their performance limitations) is reached.

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particle size distribution curve Graphic representation of the grain size distribution of soil, sediment or sedimentary rock by means of a summation curve. The particle size distribution curve is determined by a sieve analysis, in which sieves with successively smaller mesh sizes are used and each mesh size corresponds to a particular grain size. PCB (polychlorinated biphenyl) A grouping of 209 different hydrocarbon-chlorine compounds. Since the 1989 enactment of the Chemicals ­Prohibition Ordinance, the use of PCBs is forbidden in Germany. PCBs were used, for example, as separating agents (formwork oils) in concrete, impregnation sub­ stances for wood and paper, flame retardants for paints and lacquers and Thiokol sealing compounds (various connecting joints). It is persistent and lipid-­soluble. PCB is classified as being severely hazardous to water (WGK-3). It is also suspected of being carcinogenic. ­Because of the dangers that it poses, only its ­permanent removal from the biosphere, preferably its ­destruction, are acceptable for the purposes of environmental conservation. PCBs are now considered one of the “dirty dozen” known organic toxins that were banned worldwide by the 2004 Stockholm Convention. PEFC (Programs for the Endorsement of Forest ­Certification Schemes) International certification system for sustainable forest management, founded as an alternative to the FSC ­labelling system in the mid-1990s by German forest land owners’ associations and the forestry industry. PLA (polylactic acid or polylactide) Non-naturally occurring polyesters that are synthesised from sugar in a multi-step process. In the process, sugar is fermented to produce lactic acid, which is then polymerised to form PLA. The addition of heat ­allows PLA to be made into formable synthetics (thermoplastics). porous bricks Vertically perforated bricks with a bulk density under 1,000 kg/m3. The pores are created through the addition of porosifiers. Materials used as porosifiers are wood ­fibres, untreated sawdust and recycled paper fibre or ground paper as well as expanded polystyrene (recycled or new). These burn off during firing and leave air cavities behind. The use of clays that already contain organic substances (e.g. carbonaceous clays) can obviate the need for other porosifying additives. Porosifiers can comprise up to 35 % of the brick material by volume. post-consumer material / pre-consumer material Post-consumer material is waste that the end user (individual, household, business, etc.) generates at the end of a product’s usage phase. Pre-consumer (also known as post-industrial) wastes, in contrast, are generated during manufacture or production (production wastes, construction off-cuts by type, etc.). product stewardship According to the German Waste Management Act ­(Kreislaufwirtschaftsgesetz KrWG, § 23, 2.1), product stewardship encompasses “in particular [...] the devel­ opment, manufacture and circulation of products that are reusable, technologically long-lasting and suitable for appropriate harmless and high-quality recycling as well as for environmentally compatible disposal.” RC building material Recycled building material, ∫ substitute mineral building material REACH regulation This European chemicals ordinance, Regulation (EC) No 1907/2006, concerns the Registration, Evaluation,

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­ uthorisation and Restriction of Chemicals (REACH) A within the EU. It came into force on 1 June 2007. rebound effect Term that describes the quantitative difference between possible resource savings through increases in efficiency and actual savings. Efficiency-related savings can be ­entirely or partially cancelled out by changes in user / consumer behaviour. For example, price reductions due to greater efficiency can lead to increased use. recyclate Recycled material. recycled content The fraction of secondary resources in a building mater­ ial. The recycled content in ∫ MRC and ∫ MLP do not ­include: reintroductions of materials from a product’s own manufacture (pre-use/pre-consumer materials), since these can be ascribed to processing efficiency, or materials that are generated as a by-product of other manufacturing processes, since these are also not sourced from a targeted reintroduction of previously used and processed products or construction wastes. recycling If substances extracted from the breakdown of a product are used for new products at the same level of quality in a practically closed utilisation loop, they are said to have been “recycled”. This category includes all closedloop materials: most notably metals, but also biotic or minerals such as cork or loam. This definition does not include the reintroduction of production wastes, since this is simply the result of processing technique optimisation, or industrial by-products (e.g. FDG gypsum from flue gas desulfurisation plants, granulated slag, fly ash). The product of a recycling process achieves the same qualitative level as the initial product, with negligible loss in performance (∫ downcycling, ∫ upcycling). ­Recycling reduces the use of primary raw materials and therefore helps conserve resources. Example: Scrap steel is melted down to form a new steel beam. regranulate Ground plastics that are subjected to a melting process to form new granulate. renewable resources Organic resources from agricultural and forest production that are not used for nutrition or animal feed, but ­utilised to produce heat, electricity, fuels or building ­materials. reuse If a product can be used again for its original purpose, it is assigned to the “reuse” category. This category ­encompasses building materials that are long-lasing, modular or large or for which a market exists or is ­expected to exist in future. Examples include high-­ quality timber such as oak, natural stone slabs and glass facade panels, clinker bricks and stable and ­rot-proof fills such as sand and foam glass gravel. reuse potential * A quantity describing the proportion of primary re­ sources and materials incorporated in a construction that can be introduced post-use into a more-or-less closed material loop; the quantity takes into account the intrinsic material value as well as the detachability of its connections. reutilisation The reintroduction of materials or wastes into material loops through treatment or processing that breaks up the original product form. (∫ recycling or ∫ downcycling)

reversibility The ability to return to a starting point, to reverse a ­process sd value Related to ∫ vapour diffusion resistance factor secondary material / resource / building substance Raw materials generated through the recycling of wastes or residues, as distinct from primary materials taken from natural sources. Secondary resources are categorised as either ∫ pre-consumer material or ∫ post-consumer material. semiconductor Solid chemical element whose electrical conductivity ­depends on temperature (the higher the temperature, the greater the conductivity). Silicon (Si) is the most ­commonly used semiconductor in solar arrays. sharing economy or share economy Collective term for companies, business models, platforms, online and offline communities and practices that allow for the shared utilisation of entirely or partially unused resources. shared mobility Transportation strategy that offers users access to mobil­ ity services at all levels and is based on the shared or collective use of all modes of transportation. shared space In the context of mobility, a concept that allows, for ex­ ample, for the equitable use of public street space by motorised and non-motorised traffic participants alike. soil decontamination The removal of hazardous substances from contaminated soil. Depending on the contaminants present, different processes may be used. In situ: Soil is rehabilitated in its natural location without involving material excavation. Ex situ: Contaminated soil material is removed from the ground and rehabilitated on-site (e.g. in an enclosed building) or off-site (e.g. in a soil remediation facility). ­Microbiological soil treatment involves the soil’s own bacteria (with the addition, where appropriate, of struc­ tural materials (such as straw), nutrients and water) and proceeds until the soil returns to a cultivatable state (best-case scenario) or can be disposed of as a nonhazardous material. solar gain (g-value) The degree to which a transparent building component (e.g. a glass window) transmits solar energy. The g-­ value is equal to the solar heat that is transmitted through the material directly plus the secondary heat that is ­re-emitted into the enclosed space via radiation and ­convection. structural glazing (SG), structural sealant glazing (SSG) Glued, load-distributing glass constructions in which the panes are glued directly onto the support (usually ­aluminium) by means of a special silicone structural sealant. substitute mineral building materials Mineral building materials that are waste or by-products created during processing or construction and that are earmarked or suitable for incorporation in technical buildings, either as they are or after processing. sufficiency From the Latin sufficere = to be enough, to suffice. In ­sustainability research and environmental and natureconservation politics, the term is used to refer to the minimisation of resource and energy consumption through

self-containment, consumer abstinence, suitability and even ascetics. In discussions on sustainability, sufficiency is often regarded as complementary to ∫ eco-efficiency and consistency.

Urban Mining Design * A comprehensive strategy intended to close material loops in construction in order to conserve resources and avoid waste: www.urban-mining-design.de.

sustainability An operating principle for resource consumption. The principle prioritises the conservation of the essential characteristics, stability and natural regenerative ability of a system. The German version of this term (Nachhaltigkeit) was first used in 1713 by Hans Carl von Carlowitz in the context of a long-term plan for the responsible use of timber.

usage life (service life) Statistically determined time period during which mater­ ials, building products and components can be used safely for specific purposes. These types of data are published, e.g. in www.nachhaltigesbauen.de

sustainable management In the case of a forest, for example, sustainable management means that the utilisation of the land takes into account the economic, social and cultural interests of this and future generations, while also preserving the diversity of species. This standard can be used for any renewable resource. tall oil (tallol) Also known as liquid resin. By-product of the kraft ­(alkaline) process of wood pulp manufacture. It is a dark brown, viscous liquid consisting of a mixture of fatty acids, resinous acids and small quantities of non-saponi­ fiable substances.

usage costs in building construction According to DIN 18 960, all the regularly or irregularly recurring costs in built structures and on their land from the onset of occupancy until their removal (usage life). usage cost group The grouping of individual costs that are related by usage criteria. At the highest level of usage cost categorisation, the total costs are sorted into the following four usage cost groups: capital costs, object management costs, operational costs and upkeep costs (DIN 18 960). vapour diffusion resistance factor μ Resistance of a building material to the penetration of water vapour as compared to the diffusion resistance of unmoving air (μ =1). Related to ∫ sd value.

technosphere The entirety of the man-made technological environment as well as all the associated impacts on nature through landscape-reconfiguring interventions and their side ­effects. The technosphere is essentially the sum total ­aggregate of technical artefacts, resources and, not least, wastes.

VOC (Volatile Organic Compound) Organic chemicals that have a high vapour pressure at ordinary room temperature. VOCs encompass gases and vapours of organic origin in air, e.g. hydrocarbons, alcohols, aldehydes and organic acids. Many solvents, liquid fuels and synthetically manufactured substances can act as VOCs, as can numerous organic compounds that are formed in biological processes.

thermoplastics (plastomers) Synthetic materials that can be reversibly deformed within a particular temperature range. The process is repeat­ able, as long as the thermal decomposition of the material is not initiated by overheating.

waste fraction Wastes that have been separated out and are designated for reuse or recycling. Section 3 of the Commercial Waste Ordin­ance (GewAbV) classifies commercial wastes into eight waste fraction categories.

total resource productivity The sum of adjusted gross domestic product and ad­ justed import expenditure (GDP + M), divided by the combined masses of domestically used extracted resources and imports, expressed as domestic material consumption (DMC). Total resource productivity includes both biotic and abiotic resources. It is a production-­ related measurement of the resource efficiency of a ­domestic economy.

water retention capacity From the Latin retinere = to hold back, to hold: describes the ability of soil, for example, to store water.

The glossary terms marked by an asterisk * are coined and defined by the authors.

upcycling Processing of previously used products or wastes to form products whose quality exceeds that of the ­original product. An upcycled product is generally used for a more high-value purpose (∫ downcycling, ∫ recycling). upkeep Measures that are taken in order to restore the function of a faulty unit. According to DIN 31 051, upkeep is understood to include the repair and replacement of objects during the usage phase. upkeep costs One of the four usage cost groups according to DIN 18 960. The upkeep costs encompass the upkeep of buildings, technical plants, outdoor facilities and equipment. (∫ usage cost group). urban mining, urban mines Cities or settlements that serve as man-made resource repositories, in which raw primary materials removed from their natural deposits are incorporated in buildings, goods, infrastructure, products and wastes.

219

Picture Credits The authors and the publisher would like to sincerely thank everyone who contributed to the production of this book by providing images, granting permission to ­reproduce their work and supplying other information. All the drawings and the diagrams in this book were created especially. The authors and their staff created those graphics and tables for which no other source is credited. Photos for which no photog­rapher is credited are ­architectural or work photos or come from the archive of DETAIL magazine. Despite intensive efforts, we have been unable to identify the copyright holders of some images. However, their ­entitlement to claim copyright remains unaffected. In these cases, please feel free to contact us. Figures refer to ­illustration numbers.

Part A A

TEAMhillebrandt

Circularity in Architecture – Urban Mining ­Design A 1.2 Werner Huthmacher A 1.3 Nils Schäfer Holger Hoffmann A 1.4 A 1.5 Götz Wrage Cornelis Gollhardt A 1.6 A 1.7 Volkswagen AG TEAMhillebrandt A 1.8 Dismantling, Recovery and Disposal in Construction A 2.1 Levels of waste legislation relevant to dis­ mant­ling and recycling in construction, ­illustration Anja Rosen A 2.2 Anja Rosen, based on the Waste Catalogue, supplement to the European Waste Catalogue Ordinance (AVV), 2001 A 2.3 Illustration based on Directive 2008/98/EC of the European Parliament and of the Council of 19 November 2008 on waste and repealing certain directives, and the Waste Management Act (Kreislaufwirtschaftsgesetz – KrWG), 2012 A 2.4 Anja Rosen, source: Federal Statistical Office, waste balance 2014 (waste generation and whereabouts waste classifications, waste ­generated by industry branch). Wiesbaden 2016 A 2.5 Anja Rosen, source: Federal Statistical Office, “Abfallentsorgung”, Technical series 19, no. 1 – 2014, published in Wiesbaden 2016 A 2.6 Anja Rosen, source: Kreislaufwirtschaft Bau Initiative, published by Bundesverband Bau­ stoffe – Steine und Erden e. V., report on the generation and whereabouts of mineral ­construction wastes in 2014. Berlin 2017 A 2.7 After Stoll, Michael: “Recycling von minera­ lischen Abfällen – Aktueller Stand und Ausblick aus Sicht der Wirtschaft”. In: ThoméKozmiensky, Karl J. (eds.): Mineralische Nebenprodukte und Abfälle. Nietwerder 2014 A 2.8 Anja Rosen, based on Institut für Bau und Umwelt, Hochschule Rapperswil, in collabo­r­ ation with Holcim (Schweiz) AG, life cycle ­assessments of recycled aggregates for concrete. Zurich 2010 A 2.9 Anja Rosen, based on Dt. Abbruchverband e. V. (eds.): Abbrucharbeiten. Cologne 2015 – illustration after LAGA M 20 A 2.10, 2.11  Anja Rosen A 2.12 Anja Rosen, based on appendix A DIN 18 007:2000-05 Demolition work, terms, procedures, applications A 2.13 Müller, Annette: “Einfluss von Entsorgungsund Personalkosten auf die Abbruch- bzw.

220

Rückbaukosten”, data from: Schultmann, Frank: Kreislaufführung von Baustoffen – Stoffflussbasiertes Projektmanagement für die operative Demontage- und Recyclingplanung von Gebäuden. Berlin 1998 A 2.14, 2.15  Anja Rosen, based on: Deilmann et al.: Materialströme im Hochbau, Forschung für die Praxis, Vol. 06, published by Bundes­ institut für Bau-, Stadt- und Raumforschung (BBSR) in the Bundesamt für Bauwesen und Raumordnung (BBR) Bonn, 2017 A 2.16 Anja Rosen, based on: Haeming, Hartmut, ­Interessengemeinschaft Deutsche Deponiebetreiber (InwesD): Entsorgungssicherheit über Deponiekapazitäten in Deutschland, ­retrieved on 01/2018 An Overview of Rating Systems Anja Rosen A 3.1 A 3.2 Anja Rosen, data sources: BNB, DGNB, BREEAM, LEED A 3.3 Anja Rosen, based on Bundesministerium für Umwelt, Naturschutz, Bau und Reaktorsicherheit (eds.): Bewertungssystem Nachhaltiges Bauen (BNB), Büro- und Verwaltungsgebäude – Neubau, Version 2015, https://www.bnbnachhaltigesbauen.de/fileadmin/steckbriefe/ verwaltungsgebaeude/neubau/v_2015/BNB_ BN2015_414.pdf, retrieved on 29.12.2016 A 3.4 Anja Rosen, based on Deutsche Gesellschaft für Nachhaltiges Bauen (DGNB) e. V. (eds.): DGNB System, Kriterienkatalog Gebäude Neubau, Version 2018, Kriterium TEC1.6 Rückbau- und Recyclingfreundlichkeit A 3.5, 3.6 Proprietary illustration based on BRE Global Ltd. (eds.): BREEAM International New Construction 2016. Non-domestic buildings. Technical Manual, SD233 1.0 A 3.7, 3.8 Anja Rosen, based on U.S. Green Building Council (eds.): LEED v4 for Building Design and Construction (BD+C), URL: http://www. usgbc.org/resources/leed-v4-buildingdesignand-construction-current-version, as of 04/2016, retrieved on 12.11.2016 A 3.9 Illustration based on McDonough Braungart Design Chemistry LLC: Cradle to Cradle CertifiedTM Product Standard, Version 3.1, 2016 A 3.10 Blauer Engel, RAL gGmbH Natureplus e. V. PEFC Deutschland e.V. Forest Stewardship Council (FSC) ©  2009 EPEA GmbH A 3.11 KÖLBL KRUSE A 3.12 A 3.13, 3.14  Dirk Schwede and Elke Störl Using BIM to Optimise Materials Cycles in Con­ struction A 4.1, 4.2 Holger Kesting An Elastic Standard – Urban Mining and Computational Design Roland Borgmann A 5.1 A 5.2 Tobias Nolte A 5.3 Kunlin Ji Eco-Efficient Construction Using Local Resources A 6.1 Wien 3420 aspern Development AG A 6.2 Romm / Mischek ZT A 6.3 Karoline Mayer A 6.5 Romm / Mischek ZT A 6.6 Wien 3420 aspern Development AG

Part B B

© Adam Mørk/VADEHAVSCENTRET

Detachable Connections and Constructions

B 1.1 Petra Riegler-Floors B 1.2 Based on Brenner, Valentin: Recyclinggerechtes Konstruieren. Thesis at ILEK ­Stuttgart 2010, p. 54 and El Khouli, Sebastian; John, Viola: Nachhaltig Konstruieren. Munich 2014, p. 67 B 1.3 TEAMhillebrandt Dorte Mandrup B 1.4 Galerie Patrick Seguin B 1.5 B 1.6 Petra Riegler-Floors, table based on DIN 8593 B 1.7 Based on FG-Innovation GmbH, Technologie­ zentrum Ruhr: Formgedächtnistechnik – eine kurze Einführung. Bochum B 1.8 Graupner / SJ GmbH B 1.9 Maurice Spohn, TEAMhillebrandt Hans Murr Häuser in Holz GmbH B 1.10 BTW-Mietservice (Martin Groß) B 1.11 B 1.12 Krinner GmbH Switzerland B 1.13 a GEOCELL B 1.13 b FOAMGLAS® Misapor B 1.14 B 1.15 ABG Abdichtungen Boden- und Gewässerschutz GmbH B 1.16 /topmost  © Erwin Thoma Holz GmbH B 1.16 /2nd from top  Esterbauer Holzbau GmbH B 1.16 /3rd and 6th from top  inholz GmbH B 1.16 /4th, 8th and 9th from top  holzius GmbH B 1.16 /5th from top  naturi-haus.at / Zainzinger GmbH sawmill and planing facility B 1.16 /7th from top  Holzbau Willibald Longin GmbH B 1.17 Warth, Otto: Die Konstruktionen in Holz. ­Leipzig 1900, Figs. 71, 84, 90 – 92 Maurice Spohn, TEAMhillebrandt B 1.18 B 1.19 Linea Cladding Systems – Franken-Schotter GmbH & Co. KG Daas Baksteen B 1.20 B 1.21 Easyklett – Kebulin-Gesellschaft, Kettler GmbH & Co. KG B 1.22 DachTechnikBriel GmbH B 1.23, 1.24  Petra Riegler-Floors B 1.25 Petra Riegler-Floors, illustration based on DIN 18 195-9 B 1.26 Maars Deutschland GmbH B 1.27 Hölzel Stanz- und Feinwerktechnik GmbH + Co. KG B 1.28 a Maurice Spohn, TEAMhillebrandt B 1.28 b, c Joh. Sprinz GmbH & Co. KG Forbo Flooring GmbH B 1.29 B 1.30 Dry Tile, trison GmbH Petra Riegler-Floors, various sources B 1.31 Tarkett B 1.32 B 1.33 Fermacell GmbH CREATON AG B 1.34 B 1.35 thermisto GmbH B 1.36 Janßen-HeizungsSysteme B 1.37 LITHOTHERM Deutschland GmbH Frank Kaltenbach B 1.38 B 1.39 Maurice Spohn, TEAMhillebrandt B 1.40 Stabalux GmbH B 1.41 © Petschenig /Uniglas The Recycling Potential of Building Materials B 2.1 Annette Hillebrandt B 2.2 Hillebrandt with Düllmann-Lüffe, based on the Cradle-to-Cradle strategy of Braungart / McDonough B 2.3, 2.4 a Annette Hillebrandt B 2.4b Hillebrandt / Seggewies B 2.5 based on AltholzV B 2.6 TEAMhillebrandt B 2.7 Based on DIN 68 800-1 and DIN EN 335 B 2.8 Technical University of Munich B 2.9 Based on DIN 68 800-1 and DIN EN 350-2 B 2.10 Based on DIN EN 350-2016, Fig. B.1 B 2.11 Christoph Schuhknecht (Bauforum Stahl) B 2.12 Sonnenerde GmbH B 2.13 b Daniela Haussmann B 2.14 Hillebrandt / Seggewies

B 2.15 – 2.17  TEAMhillebrandt Thermory AG, Estland / Brahl Fotografi B 2.18 TEAMhillebrandt B 2.19 B 2.20 Christian Richters Claudius Pfeifer, Berlin B 2.21 Eva Schönbrunner B 2.22 © Omid Khodapanahi B 2.23 B 2.24 TEAMhillebrandt Hillebrandt / Seggewies B 2.25 istraw – straw-based building materials B 2.27 B 2.28 Susanne Reichherzer / Thermo Natur Agaton Lehmtrockenbau B 2.29 Hillebrandt / Seggewies TEAMhillebrandt B 2.30 m.schneider a.hillebrandt architektur B 2.31 Quiel, Wieland-Werke AG, Ulm B 2.32 B 2.33, 2.34  Hillebrandt / Seggewies DESSO c/o Tarkett Holding GmbH B 2.35 Baufritz Holz, Erkheim /Allgäu, Germany B 2.36 Based on DIN 4108-10 B 2.37 B 2.38 tdx / Thermo Natur B 2.39 NeptuTherm e. K. research and development Karlsruhe B 2.40 ZIRO – Die Welt der Böden, Lothar Zipse e.Kfm. B 2.41 Isolena Naturfaservliese GmbH B 2.42 Hillebrandt / Seggewies Villgrater Natur Produkte B 2.43 B 2.44 Maurice Spohn, TEAMhillebrandt CARLISLE® Construction Materials Europe B 2.45 B 2.46 Hillebrandt / Seggewies TEAMhillebrandt B 2.47 B 2.48 Hanffaser Uckermann Schüco International KG B 2.49 B 2.50 TEAMhillebrandt Hillebrandt / Seggewies B 2.51 B 2.52 based on: Prof. Dr.-Ing. habil. Anette Müller, Bauhaus-Universität Weimar, professor for materials processing and recycling, lecture D / chapter 9: Glass

dauern von Bauteilen und Bauelementen B 7.4 Petra Riegler-Floors, based on BKI – Bau­ kosten 2016 Neubau Part 3 B 7.5 Petra Riegler-Floors, based on Federal Statistical Office Wiesbaden (publ.): “Erzeuger­ preisindizes gewerblicher Produkte (Inlands­ absatz) nach dem Güterverzeichnis für Pro­ duktionsstatistiken”, 2009 B 7.6 Petra Riegler-Floors, based on BacksteinKontor, Cologne-Ehrenfeld, quote dated 03.05.2017 B 7.7 Petra Riegler-Floors, based on various ­sources B 7.8 Petra Riegler-Floors, based on CUTEC study: Prüfung und Aktualisierung von Rohstoff­ parametern. Published by the Clausthaler Umwelt-Institut. Clausthal-Zellerfeld 2016 B 7.9 Based on Paul Kamrath Ingenieurrückbau GmbH as well as information from Recyclingpark Harz GmbH, Gesellschaft für Recycling und Entsorgung, Nordharz, as of 10.02.2017 B 7.10 Petra Riegler-Floors, based on Prognos AG / Thörner, Thorsten; INFA GmbH / Hams, Sigrid: “Bedarfsanalyse für DK I-Deponien in Nord­ rhein-Westfalen. Zusammenfassung der Ergebnisse”. Study commissioned by the ­Ministry for Climate Protection, Environment, Agriculture, Nature and Consumer Protection of the State of North Rhine-Westphalia. Berlin / ­Düsseldorf  /Ahlen 2013 B 7.11 Petra Riegler-Floors, based on BKI – Bau­ kosten 2016 Neubau part 3: Nutzungsdauern von Bauteilen zur Lebenszyklusanalyse as well as on BNB and information from Paul Kamrath Ingenieurrückbau GmbH B 7.12 – 7.26  Petra Riegler-Floors, Annette Hillebrandt

Mono-Material Construction B 3.1 a Spindler GmbH Tord-Rikard Söderström B 3.1 b B 3.2 Markus Binder Wienerberger GmbH B 3.3 a B 3.3 b Jakob Schoof ZRS Architekten B 3.4 Anja Rosen B 3.5 a B 3.5 b Johan Dehlin MBA/S Matthias Bauer Associates B 3.6 a B 3.6 b Roland Halbe Petra Riegler-Floors, Markus Binder B 3.7 B 3.8, 3.9 Markus Binder

C

Beat Bühler

Detailed Catalogue S. 142, 143 S. 156, 157 S. 170, 171

Anja Rosen Anja Rosen Anja Rosen

Can Loop Potential Be Measured? B 4.1, 4.2 Anja Rosen B 4.3 Xenia Sagrebin B 4.5 Till Arlinghaus B 4.4 Anja Rosen B 4.6, 4.7 Nils Nengel B 4.8 – 4.10   Anja Rosen Assessment of Loop Potential B 5.1 Based on DIN EN 15 978 B 5.2 – 5.8 Anja Rosen Cost Comparisons of Conventional and Urban Mining Design Constructions B 7.1 Petra Riegler-Floors B 7.2 Petra Riegler-Floors, based on BKI – Bau­ kosten 2016 Neubau Part 3: Statistische Kostenkennwerte für Positionen, Paul Kamrath Ingenieurrückbau GmbH and information from manufacturers B 7.3 Petra Riegler-Floors, based on BKI – Bau­ kosten 2016 Neubau Part 2: Statistische Kostenkennwerte für Elemente, chapter: Lebens-

Christian Vorhofer thomasmayrarchive.de P. 200 Kaufmann Bausysteme P. 201 top P. 201 centre RADON Photography / Norman Radon P. 201 bottom NKBAK Adam Mørk P. 202, 203 top Dorte Mandrup P. 203 bottom Beat Bühler P. 204 top, bottom P. 204 centre Reinold Amann Beat Bühler P. 205 Stephan Weber P. 206 spaceshop Architekten P. 207 P. 208 Allard van der Hoek Jesper Ray P. 210 Christian Richters P. 211 top Ute Zscharnt for David P. 211 bottom left Chipperfield Architects P. 211 bottom centre Christian Schittich Christian Richters P. 211 bottom right FG+SG P. 212 Iwan Baan P. 213 top P. 213 bottom left Amateur Architecture Studio Iwan Baan P. 213 bottom right

Part C

Part D D

Florian Holzherr

Completed examples P. 180 Pep Sau Hisao Suzuki P. 181 P. 182 top Stadtwerke Düsseldorf AG P. 182 bottom, 183 Jens Kirchner P. 184 top David Willen Tonatiuh Ambrosetti P. 184, 185 P. 186 Norbert Miguletz P. 187 top Courtesy of Andy Ryan / The Nelson-Atkins Museum of Art P. 187 bottom Roland Halbe P. 188, 189 Dominique Marc Wehrli P. 190 Hanspeter Schiess P. 191 Cukrowicz Nachbaur Architekten P. 192 Ed White Photographics ©2015 P. 193 Michael Green Architecture P. 194 Zooey Braun P. 195 top Miljenko Bernfest P. 195 bottom Proarh P. 196 Adolf Bereuter P. 197 Georg Bechter P. 198 Christian Flatscher P. 199 EGGER Holzwerkstoffe /

221

Subject Index A 70f., 105 aerated concrete 19, 33, 70, 105 aggregates aluminium 74, 200f. 159ff. aluminium honeycomb composite panels 109 aluminium sheet cassettes 58ff. avoiding waste B biodiversity 38 61, 190ff. biotic cycle/loop 58, 60f., 65ff., 72f., biotic materials 80f., 83ff., 86ff., 92, 95 Biowaste Ordinance (Bioabfallverordnung – BioAbfV) 61 bitumen 93 88 blow-in insulation BNB (Assessment System for Sustainable Building) 24f. 25, 27 BREEAM (system) brick 32ff., 104 70 brick masonry 77 brick products bricks 213 brownfield sites 11 114 building assessment 24 building certification building cubature 11 14, 32f., 34, 37 Building Information Modelling (BIM) building life cycle 24, 27, 32 58ff. building materials building materials processing 36 118f. building physics 10 building stocks building structure 12 13 building technologies C CAM (Computer-Aided Manufacturing) 34 cardboard honeycomb panels 54 carpets 54 cash value method 125ff. 47, 93 cellar (basement) sealing 88 cellulose flakes channel glass 78, 175ff., 187 6f., 10, 16ff., 36ff. circular economy clinkers 76 6 closed-loop circulation of building materials closed-loop potential 115ff., 143, 157, 171 69, 72ff. coatings cob construction 206 86 coconut fibre Commercial Waste Ordinance (GewAbV) 17 34f. computational design concrete 69f., 104f. 42f. connection types construction (or building) product 32f., 58ff. construction phase 42 Construction Products Regulation 16, 39 construction work 37 consumer behaviour 11 copper 55, 75, 84, 122f. copper shingles 152ff. cork 88 corrosion protection 68, 74f. cost comparisons 120ff., 128ff. cost relevance 128ff. Cradle-to-Cradle system 29 cyclical process 38 D deck underlay, housewrap and facade sheeting 93 demolition materials 208, 213 detachable connections 42, 102, 118f. 135ff. Detailed Catalogue DGNB (system) 24, 26f. dismantled bricks 122f., 212 dismantling 16ff., 42, 121f. dismantling and demolition methods 19f. dismantling costs 120

222

dismantling effort disposal disposal costs double facade downcycling dry screeds dry-laid clay bricks durability class

108, 111 124 108, 111ff., 123, 142, 156, 170 211 19, 59ff. 55f. 166ff. 67

E eco-efficient construction 36f. 116 economic considerations 113ff. end-of-life paths 28ff. end-of-life phase 115f. end-of-life scenarios – post-use environmental labels and declarations 28f. EPDM 93ff. 16f., 39 EU Waste Framework Directive 90 expanded clay exterior coverings 49f. 50 exterior floor coverings F 47f. fabric wall bags facades 12, 108ff. 77, 109 fibre cement (panels) fibre insulating panels 87ff. 51 field fasteners fills 54 68ff. fire protection flat roof 50f., 79, 92f., 111, 118 111 flat roof sealing flexibility of use 12 54f. floating installation floor constructions 53ff. 53ff., 84ff. floor coverings floor structures 84ff. 84ff. floor, ceiling: surfaces 90 foam glass foam glass gravel 46f., 90, 97 109, 111 foam glass panels fossil materials 59, 61f., 75, 84, 86, 93, 95 46f., 65ff. foundation frame materials 96 42f. functional separation further use 59ff. G 175ff. glass bathroom glass ceramic 77, 144ff., 211 77 glass fibre reinforced concrete glass materials 77 glazing 95ff. Global Warming Potential 62f. glued laminated timber 192ff. 38f. gravel processing green roof structures 79f. ground screw foundations 46, 69 gutting 20 gypsum fibreboard panels 83 gypsum plasterboard panels 83 H Harvest Map hemp hollow-chamber panels hook-and-loop fasteners hook-and-loop system

59, 208 88, 95 75 45 52f.

I installation costs 120 insulating felt 88f. insulating fill 88ff. insulating gravel 90 insulating mat 88f. insulating panel 88, 90 insulating wool 88f. insulation 86ff.

interior wall constructions interior wall facing inverted roof J joining techniques jute K Kraft paper trickle protection

52 52 110 44f., 119f. 83, 89, 95 92

L landfill / landfill classes 19 124 landfill capacity 51 lap seam connection 25, 28 LEED (system) Life Cycle Assessment 24, 36 114 life cycle assessment modules 32 life cycle building 30 Life Cycle Costs (LCC) life cycles 7, 32 105 lightweight (insulating) concrete limestone 76 51 linear connection linoleum 53, 86 66ff. load-bearing structure loam 81, 104, 204 81 loam structural panels locally sourced materials 204ff. 114ff., 143, 157, 171 loop potential loose waste material fill 79 M magnetic connections 45, 53 14, 64, 113 manufacturer take-back 69 masonry materials mastic asphalt screed 84 43 material bonding material costs 120 65, 71, 78, 82, Material Cycle Status 85, 91, 94, 97, 108 64 Material End-of-Life (MEoL) Material Loop Potential (MLP) 64, 117 6, 32 material loops / cycles material purity 26f. 64, 115 Material Recycling Content (MRC) Material Recycling Content (Pre-Use) 115 10 materials categories 6 materials streams metal bathroom 172ff. 52f. metallic hook-and-loop fasteners metallic materials 59, 61, 68f., 74f., 92 104 mineral building materials mineral fibre insulating mats 90 mineral materials 59, 62, 69f., 76f., 79, 83, 90 mining 6 194, 200f. modular construction modular timber construction 198f. mono-material construction 102ff. mono-material systems 45 multiwall sheeting 75 N natural stone natural stone (panel, facade) natural stone panels nylon carpet tiles

76 50 148ff. 86

O older buildings 11 on-site concrete plant 38f. on-site raw materials production 36 on-site recycling 11, 36ff. on-site recycling materials 36 openings 95 OSB (panel) 80 owner responsibility 6

P PE-LD 93 46 perimeter insulation 79 photovoltaic systems 75, 80, 93 plastics /synthetics plywood 192 75, 188 polycarbonate panels (PC) 95 polyurethane (PU) 43 positive locking post-and-beam facade 56, 110 115, 143, 157, 171 post-use 64 post-use material 115, 143, 157, 171 pre-use product certification 28f. 96 profile materials 120 project costs R 24 rating systems raw material prices 123 6f. raw materials 126 raw materials mine 19 RC concrete rebound effect 11 66, 118f. recyclability 210 recycled building materials recycled concrete 70 211 recycled glass recycling 59ff. recycling potential 58ff. 18f. recycling quotas reed 89 42f., 73, 202f. reed thatching repository of raw materials 22 11, 58ff. resource conservation resources 36 10, 14, 84, 16f. responsibility for products retaining element 50f. 10ff., 36, 59, 64 reuse reused bricks 212 213 reused building elements 108, 111 revenues /profits from material reclamation 142, 156, 170 50, 92, 93 roof sealing sheeting roof coverings 110 51f. roof edges S sand-lime brick 32f., 70 screed tile 55, 84 seagrass 89 sealing sheeting 92 92ff. seals and separating layers 36 secondary raw materials segregated recovery 13 selective demolition 19f. selective dismantling 19f. separation (separation by type) 42ff. separation of reusable materials 19f. 89f. sheep’s wool sheep’s wool felt 83 sheep’s wool on kraft paper 92 sisal, coconut, animal hair carpets 86 slate tiles 111 solid timber 79, 192 solid timber construction 48f., 102f., 166f. solid timber diagonal-board panel 82 stainless steel 74 stainless steel clip-on panels 133, 138ff. stainless steel shell 184 steel 68f. 182 steel cassettes steel construction 49 steel facade, clip-on 182f. steel skeleton construction 138ff., 144ff., 148ff., 172ff., 175ff. straw (structural panels) 81, 195f. structural panels (interior /exterior) 80ff.

sufficiency 11 sustainability 7 6 sustainable urban development T Tadelakt 83 198ff. techno-biotic loop 60, 180ff. technological cycle / loop 72f. thermally modified wood timber beam construction 110 110 timber cladding 73, 80 timber composite panels 162ff. timber formwork 198 timber frame construction timber framework and timber panel construction 49 102, 152ff., 158ff., timber panel construction 162ff., 190ff. 65ff., 79 timber / timber composite materials U (under)floor (radiant) heating systems (UFH) unventilated facades upkeep costs urban development urban mining urban mining concept Urban Mining Design urban resource exploration use class utilisation / usage phase V vapour barrier ventilated curtain facade (VCF) ventilated curtain wall

53, 55f., 84 50 120 10 6f., 34, 38 37 10 6 66f. 42 93 49f., 109 50

W wall, ceiling: interior surfaces 83 Waste Catalogue Ordinance 16f. 16f. Waste Framework Directive waste laws 16f. 16f. Waste Management Act waste volumes 18 65 waste wood (categories) 74f., 172ff., 180f. weathering steel wind suction safeguard 50f. 56 windows and entry doors windproofing 92 65ff., 72ff., 79ff. wood / wood-based materials wood-fibre insulation 87f. 79 wood polymer compounds (WPC) wood protection 65f. 88 wood shavings Z zinc (sheet)

69, 75

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The authors and publishers wish to thank the following companies and institutions for their sponsorship of this publication: