Ceramic Material Systems: in Architecture and Interior Design 9783038210245, 9783038218432

Citation preview

CERAMIC M AT E R I A L SYSTEMS IN ARCHITECTURE AND INTERIOR DESIGN

CERAMIC M AT E R I A L SYSTEMS IN ARCHITECTURE AND INTERIOR DESIGN

MARTIN BECHTHOLD ANTHONY KANE NATHAN KING

BIRKHÄUSER BASEL

The publisher and the authors wish to thank ASCER Tile of Spain for their support of this publication.

Graphic Design, Cover and Layout: Reinhard Steger Deborah van Mourik Proxi, Barcelona Editor for the Publisher: Andreas Müller, Berlin Library of Congress Cataloging-in-Publication data A CIP catalog record for this book has been applied for at the Library of Congress. Bibliographic information published by the German National Library The German National Library lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at http://dnb.dnb.de. This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, re-use of illustrations, recitation, broadcasting, reproduction on microfilms or in other ways, and storage in databases.For any kind of use, permission of the copyright owner must be obtained. This publication is also available as an e-book (ISBN PDF 978-3-03821-024-5; ISBN EPUB 978-3-03821-593-6) and in a German language edition (ISBN 978-3-0356-0279-1). © 2015 Birkhäuser Verlag GmbH, Basel P.O. Box 44, 4009 Basel, Switzerland Part of Walter de Gruyter GmbH, Berlin/Boston Printed on acid-free paper produced from chlorine-free pulp. TCF ∞

As a rule, this book does not make reference to existing patents, registered designs, trademarks etc. If such reference has been

Printed in Germany

omitted, this does not signify that the product or the product name is not protected. The great number of different materials and

ISBN 978-3-03821-843-2

products mentioned in this book made it impossible to carry out an investigation into the possible existence of trademark protection

987654321

in every case. Accordingly, as a rule, the text makes no use of

www.birkhauser.com

trademark symbols such as ® or TM.

CONTENTS

8

CHAPTER 1

CERAMIC MATERIAL SYSTEMS 12

CHAPTER 2

FIRED CLAY – A MATERIAL LEGACY 12

From the Origins to the 19 th Century

16

18

From the 20 Century to Today th

35

Wheel-throwing

64

35

Jiggering

35

Firing and Kilns

SURFACE EFFECTS

38

Glazing

64

Introduction

38

Post-processing

66

Surface Reliefs

39

Packaging and Distribution

North London, UK 68 40

CHAPTER 5

APPLICATIONS: INTERIORS 40

Adhered Tile Systems

43

Mechanically Connected Tiles

45

Sanitary Ware

46

Museum Brandhorst, 70

Clay

19

Clay Bodies

21

Shrinkage

46

Bonded Tile Facades

22

Properties of Ceramic Parts

50

Ventilated Facades

22

Glazes

52

Screen Surfaces

25

Other Surface Treatments

53

Acoustic Surfaces

and Coatings

54

Roofs

55

Other Outdoor Applications

The Holburne Museum Extension, 72

Three-dimensional Surfaces Museum der Kulturen Basel, Switzerland Pearlescent Glazes Algueña MUCA Music Hall and Auditorium, Alicante, Spain

78

Glaze Transfers

80

High Performance Surfaces

One Eagle Place, London, UK West Beach Promenade, Benidorm, Spain 82

Inkjet Printing La Mandarra de La Ramos, Pamplona, Spain

84

Nano-coatings Pinnacle, Bologna, Italy

CHAPTER 4

PRODUCTION PROCESSES

Custom Glazes Bath, Somerset, UK

CHAPTER 6

APPLICATIONS: EXTERIORS

Color Variation Munich, Germany

74

18

26

The Wallpaper Factory, Islington,

CHAPTER 3

MATERIALS AND MATERIAL PROPERTIES

CHAPTER 8

56

CHAPTER 7

MATERIAL FLOWS: LIFE CYCLE ASPECTS

28

Dry-pressing

29

Extrusion

58

Extraction-to-Production Phase

31

Slump Forming/Slump Molding

59

Construction and Use Phase

32

Die-cutting

60

End-of-Life Scenarios

32

Plastic Pressing

62

Life Cycle Analysis (LCA) and

33

Slip Casting

Material Comparisons

5

86

CHAPTER 9

118

PATTERNS AND AGGREGATIONS

CHAPTER 10

THERMODYNAMIC SKINS

148

CHAPTER 11

FORM CUSTOMIZATION STRATEGIES

86

Introduction

118

Introduction

148

Introduction

88

Complex Geometry

120

Reclaimed Tile Tectonics

150

Computer-aided Slump Molding

90

94

Pulsate, Primrose Hill,

Warehouse 8B Administrative

London, UK

Offices, Madrid, Spain

Complex Assembly

124

100

104

Jardim Botânico Tropical,

Mainz, Germany

Travessa do Marta Pinto,

Non-repeating Patterns

Belém/Lisbon, Portugal

Villa for an Industrialist,

Masonic Louvers

Shenzhen, China

126

Student Services Building, University of Texas at Dallas,

Kosemo Brick, Archie Bray

Louisville, Kentucky, USA

Texas, USA

Foundation, Helena,

Modulating Light

Montana, USA

Curved Surface Urban Mosaics

130

Low-volume Custom Extrusion

Addition to the Israel Museum,

Barcelona, Spain

Jerusalem, Israel

Ministry of Urban Development

Perforated Slab

and Environment,

School Library, Gando,

Hamburg, Germany

Robotic Tiling

134

Burkina Faso

166

170

Systemic Variation

Digital Reconstruction

Cool Cavity

Alberta Legislature Building

Urban Guerrilla, Valencia, Spain

Patio 2.12, Andalucía Team, Solar

Dome Reconstruction, Edmonton,

Hanging Assemblies

Decathlon Europe 2012, 2nd Prize,

Alberta, Canada

Tessellated Surfaces

136

Madrid, Spain

Chengdu, China

114

162

Santa Caterina Market,

Xinjin Zhi Museum, 112

High-relief Slip-cast Surfaces

Muhammad Ali Center,

Ames, Iowa, USA

108

Aichi, Japan 158

Figurative Urban Mosaics

Iowa State Mural, 106

Volumetric Pixelization Spanish Pavilion, Expo 2005,

Grão – Ceramic Pixels

Jewish Community Center,

Zamet Center, Rijeka, Croatia 98

Villa Nurbs, Empuriabrava, Spain 154

140

172

Three-dimensional Assemblies

Spanish Pavilion at the

3Dx1, Milan, Italy

International Exposition of

Restaurant, Ditzingen, Germany 176

Zaragoza, Spain

Structural Assemblies Casalgrande Ceramic Cloud (CCCLoud), Reggio Emilia, Italy

144

Delineated Parallax La Riera de la Salut Remodel, Sant Feliu de Llobregat, Spain

BIO SKIN Sony Research and Development

Angular Variation Trumpf Industrial Campus

Breathing Columns

180

Office, Tokyo, Japan

Aggregate Production Processes Oceanário Addition, Lisbon, Portugal

184

Compound Surface Discretization Museum de Fundatie Extension, Zwolle, Overijssel, The Netherlands

6

188

CHAPTER 12

EMERGING SYSTEMS

PRODUCTS AND TECHNOLOGIES

APPENDIX

188

Introduction

206

Introduction

218

About the Authors

190

Robotic Tile Mosaics

207

Large-format Production Lines

219

Index of Names

Design Robotics Group at Harvard

207

Large-format Tiles: Neolith,

221

Subject Index

Techlam, Maximum

223

Sponsor’s Profile

208

High-strength Porcelain:

224

Illustration Credits

to-Robotic Production

208

Bioactive Ceramics: Bionictile

Design Robotics Group at Harvard

209

Slumped Tile: UP

University Graduate School of

209

Slumped Tile: STAR

Design

210

University Graduate School of Design 192

194

196

SaphirKeramik Sink

Integrated Environmental Design-

Translucent Porcelain: SlimmKer-Light

Thermally Active Building Envelope

210

Modular Ceramic Stove

The Center for Architecture,

211

Berlin Stove Tiles

Science and Ecology, Rensselaer

211

Keramos Cabinets

Polytechnic Institute and

211

Inkjet-printed Tiles: Emotile

Skidmore, Owings & Merrill (SOM)

212

Physical Vapor Deposition: Metallic Coatings

Structural Ceramic Shell Material Processes and Systems

213

Laser Engraving

Group at Harvard University, Graz

213

Recycled Tiles

University of Technology

213

Preassembled Systems: Flexbrick

198

Photosensitive Blueware

214

Ceramic-Concrete Composition

200

Foamed Ceramics

214

Ceramic Louver System: Shamal

European Ceramic Work Center,

215

Photovoltaic Roof Tiles: Panotron

Joris Laarman Studio BV

215

Ceramic Wardrobe: Milky Star

202

Additive Ceramic Systems

216

Acoustic Ceramics: Acoustic

204

Automated Material Manipulation 216

Industrial Tile: Acigres

216

Material Mimicry: Age Wood,

Studio Glithero

System: Terraclad

Shingle

Age Beton, Age Blend

7

CHAPTER 1

CERAMIC MATERIAL SYSTEMS

The past decades have been marked by the rediscovery of architectural ceramics—a material system that has long served merely as a practical surface treatment for buildings, but that is now coming into its own as a multi-functional, intensely aesthetic boundary layer for buildings, landscapes, and cities. This renaissance is enabled and catalyzed by recent advances in material science, fastening technology, industrial production methods, design computation, digital fabrication workflows, and design robotics. Today’s highly controlled clay mixes, combined with computer-controlled kilns, can be customized to design specific material behaviors. Rigid industrial mass-production systems are being complemented by fabricators geared towards collaborating with architects in the development of custom solutions for buildings. Project-specific ceramic designs are increasingly supported by digital environments that address the entire material life cycle from production to robotic assembly approaches. Glaze technology has always been among the most forward-looking aspects of ceramic elements, and recent advances such as self-cleaning or pollution-reducing glazes continue this tradition. These developments now afford architects and other design professionals new opportunities for aesthetically committed, structurally and environmentally active ceramic systems that far transcend the ubiquitous tile as a solution for water-resistant, durable finishes. Ceramic material systems comprise the ecosystem of material extraction and processing to the assembly of construction elements and their eventual reuse and recycling. They are moving from the margins to the forefront of contemporary construction and design culture (1). This book establishes the state of the art of this quickly emerging field, with a particular interest in presenting the knowledge needed for developing project-specific solutions that often involve custom ceramic elements. Doing so requires, on the one hand, a rigorous background of the materials and associated technologies, and on the other, inspiration from the very best built examples of ceramic systems today. The book not only addresses both of these related needs, but also presents the most promising emerging developments and research that will likely shape the future design of ceramic elements and processes. For most laypeople—and indeed for many design professionals—the term “ceramic” is synonymous with surfaces covered by flat tiles, bonded with mortar or adhesives, and sealed with grout joints. Indeed, that description fits the vast majority of present and past ceramic applications, and it continues to serve us well. Glazed or unglazed ceramic surfaces are durable, moisture-resistant, and inflammable. The incredible wealth of tile patterns and glaze colors reflect our diverse cultural and societal heritage (2). But adhering tiles to rigid underlying surfaces is limiting.

Multiple technical advances have brought about much larger, extremely slender, structurally more capable ceramic elements that, when used with mechanical fasteners, allow ceramic claddings to diverge from their slavish adherence to the geometry of supporting walls. These cladding systems feature ceramic elements in their own distinct layer, interacting in new performative ways with the environment. Ceramic elements now can control the transfer of moisture, heat, or sound. They construct deeply contoured surface layers that support new forms of architectural expression. They buffer and modulate daylight. In short, ceramic surfaces now enable multifunctional physical boundary layers that enrich and improve life in buildings and cities alike (3). 1

2 Complex tile patterns in a mosque in Saint Petersburg, Russia.

3 The ceramic facade for the Sony Building in Osaka, Japan, designed by Nikken Sekkei Ltd., uses evaporative cooling to improve the occupants’ comfort and lower the microclimate around the building at the same time.

The Hamburg State Ministry for Urban Development and the Environment in Germany, designed by Sauerbruch Hutton, features a richly colored ventilated facade that includes planar and single-curved pieces.

From a material science standpoint ceramics are oxides, with particular molecular bonding characteristics. They include, among others, cement-based materials, glass, clay-based materials, as well as so-called technical ceramics consisting of alumina, boron, graphite, silicon, and other substances. This book deals with glazed or unglazed clay-based ceramics that are, more specifically, relatively thin compared to their surface area, and fired at high temperatures to produce hard and durable products. Typical examples include multi- and single-layered ceramic panels used for claddings, shaped ceramic roof tiles, wall and floor tiles, as well as the many specialty elements for sunshades, screens, landscaping elements, and other applications. Bricks and brick products, despite being made from similar clays, are not included; instead, the reader is referred to the extensive existing literature.1

9

Ceramic elements, i.e., the fired-clay base shape, often bonded with a glaze or other finish, combine with adhesives or mechanical fasteners, grout and sealants, and other support elements into functionally complex construction systems. The material system view expands the scale of consideration further by including analysis of, and research on, relevant fabrication methods, understanding of the associated supply and distribution networks, and the life cycle study of resource flows. Understanding the basic principles of contemporary production techniques for ceramic elements is important for designers who want to go beyond purchasing a standard product. Production techniques determine the characteristics of the end product to a high degree. Industrial mass-production settings are extremely unforgiving and inflexible, while craft-based manual techniques tend to be rather accommodating. Wall and floor tiles, for example, are produced in both settings. Hand-molded tiles feature subtle color and form variations that are appreciated by many end-users such that a small but sizeable market continues to exist (4). Such tiles contrast visibly with industrially made products that tend to be more uniform in color and size unless, of course, post-processing techniques have deliberately been used to create the “look and feel” of a hand-made tile. The highly automated production systems with their high set-up and tooling costs practically exclude the production of custom tiles (roof, wall, or floor products) for a specific project (5). But even companies that hand-mold tiles are rarely set up to communicate directly with designers who might wish to pursue a project-specific solution. Tiles are typically sold through resellers who receive their products from distributors, so that architects and designers are far removed from the actual places of production. 4

Hand molding of tiles at Ceràmica Elías near Barcelona, Spain. After molding and drying, the handmade tiles are fired in the same computer-controlled kilns used for mass-produced tiles made in the same factory.

5 Highly automated mass-production of dry-pressed floor tiles at Porcelanosa, Castellón, Spain. Industrial production settings such as these can output several thousand tiles per hour.

CERAMIC MATERIAL SYSTEMS

Producers who primarily focus on facade elements are organized in a slightly different way. Their products represent the largest, most structurally capable ceramic elements on the market. Industrial production methods dominate, but the need to customize solutions project by project has created an industry setup where medium-size producers are geared to collaborate with architects, engineers, and facade consultants in developing and producing custom ceramic systems for building envelopes. Appropriate fastening substructures are usually included in the scope of work, even though their production tends to be outsourced. This approach represents the middle ground between craft-based hand molding (low-volume but flexible production) and industrial mass-production (high-volume, inflexible), combining the best of both worlds. The relative ease with which even three-dimensional pieces with unique expressions and performance characteristics can be created differentiates ceramics from many other cladding and surface finish systems. The costs of ventilated ceramic facades tend to be similar to equivalent stone facades, but with the added advantage of a vastly increased potential for design intervention in form and functional customization. Broadened design scope is one of the main reasons for today’s rediscovery of ceramic material systems. It allows architects to engage a long material legacy while still pursuing forward-looking, conceptually and tectonically ambitious designs (6). 6 The extension of Antoni Gaudí’s Teresianas School in Barcelona, Spain, designed by Picharchitects, features a facade composed of hollow ceramic extrusions. The so-called Flexbrick system features ceramic elements clipped onto a thin wire mesh to create a semi-transparent screen that filters light and views.

Following this introduction, Chapter 2 introduces an evolutionary perspective on ceramic material systems. The following chapters introduce the material properties and production processes (Chapters 3 and 4) used to create ceramic elements for applications in the built environment, followed by Chapters 5 and 6 that survey common applications, from interior adhered surface finishes to bonded facades, ventilated facades, sunscreens, acoustic claddings, and more. Chapter 7 on life cycle design outlines resource use and environmental issues from material extraction to end-of-life scenarios. Chapters 8 to 12 are dedicated to case studies of the most interesting, forward-looking, and inspiring uses of ceramic systems in buildings. The cases are grouped by themes that best represent the unique opportunities of ceramics: surface effects, patterns and aggregations, thermodynamic skins, customization strategies, and emerging technologies like 3D ceramic printing, ceramic-concrete composites, robotic construction, and others. Each section includes an introduction that addresses the general issues relating to each theme. The last chapter on Products and Technologies presents a selection of current products from a range of producers. The intent is to provide a glimpse of product trends that complement architecturally ambitious design pursuits with ceramic material systems.

11

NOTE 1 For example Pfeifer, G. et al., Masonry Construction Manual. Basel, Boston, Berlin: Birkhäuser; Munich: Edition Detail, 2001.

CHAPTER 2

FIRED CLAY – A MATERIAL LEGACY

1

The Venus of Dolní Věstonice is among the earliest ceramic figurines found, dating back to 29000 to 25000 BC. It was discovered in 1925 in Moravia, Czechoslovakia. Fingerprints embossed into the surface even let scientists trace back the handling of the unfired object by a child between the age of seven and 14.

From the Origins to the 19 th Century The history of humanity, of civilizations dating back tens of thousands of years, is inextricably linked to firing clay and transforming it into a stone-like, durable material—ceramic. This hard, water-resistant material formed vessels, ovens, musical instruments, eventually tiles and sanitary ware, and much more. The word “ceramic” translates from the Greek keramikos or keramos, describing the product of the potter’s art.1 But long before humans produced ceramic tableware or cookware they made figurines and sculptures for ceremonial use.2 The earliest fired clay figure found to date originates from a Stone Age settlement excavated in the 1920s in Czechoslovakia. Archeologists date this small female figurine to between 29,000 and 25,000 BC (1). Remnants of a purposefully constructed kiln were found on the same site—one of, or maybe the first ever, organized ceramic productions that ultimately led to today’s fully automated production environments.3 Ceramic is considered the first human-designed material, as opposed to materials that were essentially used as extracted from nature and just shaped for specific purposes (e.g., wood, stone). Neolithic gatherers and hunters already employed fired clay items sporadically, but there is evidence that ceramics became more widespread once humans started to settle. Firing changed the material composition on the particle scale as clay, sand, and other materials were sintered and permanently bonded under the intense heat. Material properties changed substantially in the process, creating a harder, durable, and water-resistant substance. This manmade material—ceramic—had properties similar to stone, but was easier to shape and work while soft compared to the tremendous effort of chiseling and shaping stone. This ease of shaping ceramics remains attractive to the present day. Early vessels for consumption and storage of food and liquids were initially hand-built using similar techniques employed by artists and hobbyists today. These manual techniques were supplemented and eventually replaced by one of the first machines ever invented—the potter’s wheel. This simple yet effective device probably evolved around 3,500 BC in the Middle East and in China, and in principle has changed little to the present day. Its attraction lies in that it combines the regular and predictable rotational movement with direct hand-control—a clever method to lower the cost of repetitive as well as customized pottery production. Regular forms can be produced relatively easily and economically and without costly molds and templates. However, while the range of possible shapes is immense, the output is limited to axi-symmetrical shapes.

The desire to decorate ceramic ware and push designs beyond purely practical uses is almost as old as ceramic production itself. Early pottery often imitated textures from other production techniques such as weaving reed or wood. Color was likely first introduced through fire clouds, dark discolorations of the ceramic body from firing it in an oxidizing or a reducing atmosphere. When firing red earthenware, for example, the iron in the clay reacts with oxygen in the atmosphere and turns the ceramic bright red. Cutting off this oxygen supply turns the same ceramic black. Early Egyptian and Chinese cultures understood and deployed this discoloration, initially discovered by accident, to add value to some of the world’s earliest ceramic vessels. The best-known use of this technique is arguably the black and red pottery of ancient Greece around 500 BC. Beyond manipulation of the ceramic body itself, craftspeople have been using glazes, thin glass-based coatings. Such vitreous coatings consist of a glass former (silica), a flux to cause the silica to melt, and a refractory element to give it durability. Their first use dates back to ancient Egypt and Mesopotamia. In the stepped pyramid in Saqqara (2,667–2,648 BC) of pharaoh Djoser glazes with copper oxides were used to produce thousands of small bluish-green tiles resembling turquoise and lapis-lazuli to adorn the burial chamber (2). Another type of early glaze was the salt glaze: salt in the clay body migrates to the surface, where it reacts with the clay silica to form a vitreous coating. Later, powdered glass became a common glaze component and various metal oxides were used to create a range of colors. Since then glazes continue to evoke other, more noble materials. They also prolong the life of ceramic elements by keeping the often porous ceramic material dry. 2 Early blue-glazed ceramic tile used to decorate tomb interiors at the Djoser pyramid in Saqqara, Egypt. The tile measures 36 × 60 mm and is 13 mm thick. Approximately 36,000 tiles were molded for the project. They feature a projection on the back used to connect them to wet plaster substrates. The hole allowed a wire to mechanically secure the tile to the wall—much like mechanical connectors used in modern ceramic construction.

The centers of pottery production were usually in close proximity to where suitable clay could be readily extracted, thus avoiding costly and slow transport of heavy clay. Affordable fuel sources were needed as well, starting with wood or dung, and eventually switching to coal and natural gas as well as electricity. Many early production centers often started with small-scale pottery that gave way to more systematically organized manufacturing activities. Many of today’s industrial producers remain in these original locations, still affecting local economies despite a now more widespread network of clay extraction and its associated trade. Landscapes in parts of the worlds have literally been shaped by clay extraction, but environmental problems are relatively minor compared to surface mining of coal or other minerals. The earliest ceramic artifacts were fired in open fires that led to rough ceramic end products. Exposure to the elements allowed wind and rain to change firing temperatures suddenly—most certainly leading to much loss during ceramic production. Fuel consumption was high, controls were limited, and danger to the craftsperson and the surroundings was always imminent. The development of enclosed ovens, or kilns, satisfied the need for efficiency, and eventually allowed for the production of higher-quality, finer ceramics as a result of slower, more controlled firing sequences.

13

This also permitted the know-how and sophistication of glazes to evolve considerably. Along with material composition, firing sequences thus evolved as the second way through which potters—or should we call them the first material designers—created desirable material properties. Early pottery kilns served as catalysts of innovation far beyond ceramic production. Around 3,500 BC kilns had evolved whose temperatures were high enough for the reduction of the minerals azurite and malachite into copper. This discovery paved the way for blending tin and copper in the production of bronze, ushering in the Bronze Age. Early kilns may have been (partially) dug into the ground or were self-supporting vertical, dome-shaped structures. Cross-draft kilns were an attempt to increase interior volume and better control the distribution of heat. But these kilns had to cool down for loading and unloading, disrupting production cycles and increasing fuel consumption. Fire temperatures were key, and with the emergence of industrial methods more continuous production cycles were highly desirable. The logic of continuous production is best represented in today’s computer-controlled tunnel kilns, horizontal chambers with evenly distributed heat sources throughout, where green clay elements enter on one end, travel through a sequence of temperature zones, and warm ceramic products exit on the other. The production techniques that had been developed for pottery transferred relatively easily to elements used in buildings. Sun-dried clay had long been used as plaster and brick in the Near East.4 Fired ceramic tiles were first developed most likely in Ancient Egypt, as demonstrated by the tiles for the Djoser pyramid discussed earlier. Another early example of ceramic elements as building cladding are the tile-like cones used around 3,300 BC in the Sumerian city of Uruk. The ceramic cones were pressed like nails into an outer mud layer and served as a protective layer. They were painted and organized to form geometric patterns similar to the later tile mosaics. The Assyrians and Babylonians are later cultures that used colorfully glazed tiles. Some of their best-known brick and tile work introduces three-dimensional reliefs as a design feature. The Ishtar gates in Babylon (~ 580 BC)5 show a compelling glazed example, even though the format of the elements was more brick-like. Here careful planning must have taken place to assemble the 60 lion reliefs from many glazed pieces in regular vertical layers. It is assumed that the production involved molds used to prefabricate identical elements for the lions, thus constituting one of the earliest examples of prefabrication methods using indirect (i.e., mold-based) techniques (3). Chinese culture contributed much to advances in ceramic technology and applications, from pottery to exuberant roof tiles and figurines. Around 2500 BC, Chinese potters invented porcelain, a particular kaolinite mix fired at higher temperatures to produce a vitrified material that is more durable, harder, and absorbs less water. The long-lasting Chinese leadership in developing ceramic technology is still reflected in the naming of one of the dominant raw materials as kaolinite; the name traces back to the Chinese city of Gao Ling, a mountainous area of ceramic discovery in early China. Over the centuries the knowledge of clay bodies, firing techniques, and glazes grew. Wooden Greek temples were adorned with terra cotta friezes and column claddings to produce a more solid, stone-like impression. These were painted to blend with other materials. Ceramic roof tiles protected these and other buildings from the elements. Production techniques transitioned from manual methods to pre-industrial serial production techniques using animal or water power to mix clay bodies. Roman engineers set up efficient production centers for the making of roof, wall, and floor tiles (4). Ceramic roof tiles finally allowed for durable roof systems in the wet climates

FIRED CLAY – A MATERIAL LEGACY

3

4 The reconstructed Ishtar gate of Babylon at the Pergamon Museum in Berlin, Germany. Glazed relief tiles were likely molded in small lots to reproduce the lion reliefs.

Reconstructed Roman roof tiles in an archeological park in Xanten, Germany. Tiles were serially produced and held in place in heavy mortar beds. Similar cap and pan designs still exist in the present day.

5 Highly decorated chien nien roof elements at the Mengjia Longshan temple in Taipei, Taiwan. Elaborate ornamentation was traditionally reserved for use on temples and palaces. The figures express authority and are to protect from evil spirits.

of Northern Europe. The Romans also embedded large hollow ceramic vessels in their concrete domes, saving material and lightening dead loads. Larger elements could now be produced in more substantial facilities, bringing down cost that in turn helped to spread their use. Much of this advancement was forgotten in Europe after the demise of the Roman Empire, and relatively little progress took place from the Middle Ages to the Industrial Revolution. Islamic architecture produced some of the most compelling ceramic mosaics in the period between 750 and 1,300 AD. Complex architectural forms, such as the doubly curved domes and mihrabs (semi-circular niches)—often embellished with hundreds of muqarnas (corbels)—were surfaced with glazed ceramic mosaics. Chinese architecture has used glazed decorated roof tiles for centuries. In the 17th century figures were introduced, a tradition very much alive today in the repeatedly reconstructed temples (5). During the Renaissance ceramic ornaments and figures were used on buildings, but their true materiality was usually downplayed by reproducing the appearance of stone. Beginning around 1840, ceramic elements for building facades—known as terra cotta, Italian for “baked earth or clay”—again became an essential and economical choice when highly ornamental features were desired, yet carved stone was either unavailable or too expensive. Terra cotta was not only aesthetic and economical, it also protected 19 th century iron and steel structures from fire. The survival of many terra cotta-clad buildings during the 1871 Chicago fire demonstrated the advantage of terra cotta in combination with metal building frames compared to brick facades and timber structures. Production methods were based on full-scale detail drawings, dimensioned to compensate for shrinkage. Sculptors produced positive plaster plugs from which plaster molds were subsequently cast. Moist clay was hand-pressed into these molds and removed for glazing and firing, once the originally wet clay had been sufficiently dried (e.g., green state). The resulting richly detailed, ornamental terra cotta elements were widely used. They became essential with the development of high-rise buildings in 19 th century USA (6), and promoted the development of the modern curtain wall with their thin, lightweight claddings. The work of Louis Sullivan and the firm Adler & Sullivan became exemplary of this period and remains inspirational in its use of intricately detailed terra cotta elements. Ceramic was frequently

15

6 The USA-based National Terra Cotta Society, founded in 1911, issued standard details for terra cotta-clad buildings, both for steel frame structures as well as for steel/concrete buildings.

disguised behind layers of paint or glazes, often painstakingly executed to mimic other, more noble materials such as stone (7). The intrinsic materiality of fired clay was rarely appreciated as clients, as well as many architects, valued a more traditional appearance. During this period Rafael Guastavino patented and successfully commercialized his fireproof tile vaults in the USA, creating one of the first structural applications for ceramic tiles. Combinations with brick such as in Harvard University’s Sever Hall by H. H. Richardson were widely used in the second half of the 19 th century (8). Richardson used ceramic systems as ornamentation, leaving the brick for the walls and arches, and cut stone for special pieces such as keystones. This tectonic language already points towards the emerging appreciation of ceramics as a pure cladding, without pretense of a tectonic role designated to steel and concrete. 7

8 Adler & Sullivan’s Guaranty Building in Buffalo, NY, USA, was completed in 1896. Some of the highly ornamental, complex elements have been recently recreated and replaced using handpressed molding techniques almost identical to the methods employed when the building was first built.

Sever Hall, completed in 1880, is an example of using terra cotta to “embellish” brick buildings in the Northeastern United States. Ceramics are used for highly ornamental elements only, and in combination with cut stone.

From the 20 th Century to Today Architects such as Frank Lloyd Wright led a slow turnaround towards a new appreciation of ceramic as a material system with its own inherent expression. The Modern Movement continued this incremental change in attitude, but only relatively few architects had more than a cursory interest in the material. The Bauhaus maintained a ceramics studio with a pottery focus during the Weimar years, abandoning the study of this material in 1925, and never engaging with ceramic systems as an industrially producible material. Arne Jacobsen’s Stelling House and Henry van de Velde’s Tweebronnen School (1937–1940, now converted into a library) used glazed flat ceramics—albeit not always to the public’s liking. Architects like Alvar Aalto introduced glazed tiles as a deliberate choice, indulging in their colorful surfaces as accents within modern interiors. Starting in 1954, Eladio Dieste expanded Guastavino’s structural use of ceramics with his tile shells in Uruguay and Spain. Jørn Utzon’s Sydney Opera House (1956–1973) features over 1,050,000 ceramic tiles pre-applied onto precast panels that make up the outer roof surfaces. The use of bonded tile facades became more widespread in many parts of the world, especially in Eastern Europe and the Soviet Union after World War II, and later in parts of Asia. Economic concerns, combined with the well-known practical advantages of durability and water resistance, drove much of this interest. A major breakthrough occurred when larger ceramic elements were designed to be freely suspended outside the enclosed building envelope, serving as a rain screen and protecting other layers such as the insulation or the water barrier from the elements. Better control of clay bodies reduced the risk of fractures that occasionally plagued earlier terra cotta facade ornamentation. Engineering analysis advanced sufficiently to model the connections and design them safely. Production methods evolved with the refinement of machines such as extruders used initially for brick production,

FIRED CLAY – A MATERIAL LEGACY

9 Following Renzo Piano’s earlier residential projects in Paris, France, the IRCAM studio was the architect’s first implementation of a ceramic rain screen for a public building in a prominent location in the historic center of the city.

adding enough control to transform a production model still based on craftspeople handling relatively wet clay mixtures in molds to one that relied on high-volume manufacturing techniques such as extrusion and dry-pressing. With these developments ceramic systems finally came into their own. In Germany, Thomas Herzog at the TU Munich developed a first ceramic ventilated facade jointly with fabricator Moeding. The first installation was executed on a project in Munich’s Lohhof quarter in 1984. Renzo Piano continued the development of ventilated terra cotta facades on his projects in France. His office worked closely with manufacturers such as Giraud Frères in Southern France. The IRCAM studio, completed in 1990 near the Centre Georges Pompidou in Paris, was among his first projects (9). These collaborations between architects and producers created innovative construction solutions that are now widely applied, encouraging several manufacturers to focus on custom production and collaboration with architects as their core business model, a tradition that has enabled much of the most interesting and forward-looking work in architectural ceramics. Industrial tile manufacturers have continued to mass-produce tiles based on market research, and this segment represents the bulk of the production volume. Tile customization through inkjet printing is now entering even these industrial companies, linking them closer to the end-user than ever before. The present manufacturing culture in the ceramics industry continues to be dominated by the duality of relatively few and small craft-based firms and the many highly industrialized tile companies. This book does not favor either, but raises awareness of different production cultures along with their specific abilities and constraints. A small number of companies specialize in producing facade elements and most are geared to working with architects, engineers, and facade consultants to design and ultimately manufacture custom elements. Some industrially produced varieties continue the tradition of disguise by displaying a myriad of surface effects, from photorealistic representations of wood or stone to actual images or text. The aesthetics of ceramics have become widely appreciated for building envelopes, allowing contemporary modes of expression even in a realm otherwise dominated by brick construction.

17

NOTES 1 Oldfather, W. “A Note of the Etymology of the word ‘Ceramic’”. Journal of the American Ceramic Society. Vol. 3, Issue 7, July 1920. pp. 537 – 542. 2 The durability of ceramics did not only serve its early users well, it also preserved these artifacts over thousands of years, helping today’s historians to better understand ancient cultures. 3 Other early ceramic objects date back to around 7,000 BC in the Near East and the Middle East. Chinese pottery can be traced back to 6000 BC. 4 The earliest evidence of using unfired clay bricks is the use of adobe clay bricks in Jordan around the 9 th century BC. It is interesting to note that the use of fired ceramic pottery was widespread long before that, but entered construction culture relatively late in Sumeria (in today’s Iran) around the 4th century BC. Fuel was expensive, and might have included a mix of camel dung and plant materials, limiting the use of the fired clay bricks on the exterior wall surfaces where they provided a durable surface layer. 5 The gate has been reconstructed in the Pergamon Museum in Berlin, Germany.

CHAPTER 3

MATERIALS AND MATERIAL PROPERTIES

The properties of ceramic materials enable a variety of architectural applications. Hardness, density, durability, ability to take on a wide range of finish appearances, and other properties have facilitated the application of ceramics in buildings throughout the world for centuries. Brittleness and lack of tensile strength are disadvantages that need to be compensated for with appropriate part and system design strategies. Clay-based ceramics have unique regional material characteristics that vary based on the geological conditions in a given location over centuries (1). Modern architectural ceramics have highly tailored material properties that are determined by specific mixes of raw materials (clay bodies). Transformation from clay to ceramic occurs during the sintering or firing process, and in some cases the material is vitrified, resulting in a non-porous homogenous product. Material properties should be discussed as they change between unfired stages (clay), fired stages (ceramic), and finished stages (glazed, etc.). The following chapter details each of these phases leading to an in-depth look at forming processes in Chapter 4. 1 Raw clay materials at a Ugandan ceramic production facility.

Clay “Clay” is a broad term describing a family of naturally occurring materials that have unique compositional and material properties and when fired become ceramic. Clay is abundantly available across the globe, primarily composed of alumina, silica, and water (Al2O3 +2SiO2 +2H2O), and formed naturally over geological time periods through the decomposition of igneous rocks, especially granite, into feldspar through weathering and chemical action. Combined with a chemical hydration process, the decomposition of feldspar into alumina and silica along with other minerals results in clay, both residual clay (primary clay) as well as sedimentary clay (secondary clay). Residual clay remains in the site of the original feldspar and is often the purer and more rare of the two types. The more common sedimentary clay is typically more plastic and forms the basis for the vast majority of current architectural ceramics production. Wind, water, and glacial forces can transport sedimentary clays from their origin. During this process clays often become contaminated with additional minerals and organic compounds, giving clays from different geologic regions unique characteristics (2).

Most clay bodies for architectural ceramics are earthenware and stoneware—both sedimentary clay types—as well as porcelain. These terms, used in common language to reference pottery, here designate technical expressions of the blends of clays and additives (3). Further distinctions are made based on the nuanced compositions within each type of clay. Earthenware, including terra cotta, is a common low-fire clay body well-known from flowerpots and often used for roof tiles, thick tiles, and bricks or larger facade elements. Particle size in the earthenware clay bodies tends to remain relatively large. Stoneware is commonly used for architectural tile applications as well as for facade elements. It consists of finer granules, exhibits better mechanical properties, and is less porous. Glazed water pipes for urban water systems are commonly produced in stoneware. Porcelain is a white kaolinite body, fired at the highest temperatures, and usually fully vitrified to make for very low water absorption even without a glaze finish. Any of these basic clay bodies can be prepared as near-liquid casting slip by adding deflocculants. These are typically sodium silicates used to dispel the electrical attraction between the clay particles, thereby keeping the clay in a liquid, low-viscosity state. Casting slips are used in the molding of geometrically complex, often hollow, parts. Toilets and sinks are typical products manufactured using slips (see Chapter 4 for process details).

Lighter in color

Porous

Today, the design and production of clay bodies is a specialized field combining chemistry with process engineering. Clay bodies are critical to the performance of the resulting ceramic elements, and their design requires deep knowledge of the materials as well as the production processes. Given the complexity of the issue, this part of the design process, while based on the performance specifications provided by the design team, is designated entirely to the producer. Many producers have material scientists, chemists, or ceramic engineers on staff that customize clay bodies and the related firing strategies and also coordinate the many glaze finishes.

2

Earthenware

Dense

Clay Bodies Over time, first craftspeople and later chemists and material scientists developed highly specialized knowledge that today allows for the design of “clay bodies”— blends of different clays and additives—in response to project-specific needs. When combined with firing techniques that regulate temperature profiles over time, the resulting ceramic materials are highly customizable, with significant variations in density, porosity, strength, and thermal properties.

Porcelain

Darker in color

Terra cotta *

Stoneware

Diagram of common earthenware, stoneware, and porcelain clay body compositions.1 * Terra cotta is often considered an earthenware and the term is typically used to refer to all reddish and brown porous ceramics in architectural applications.

3

Common red clay

30

Stoneware clay

25

Red clay

B

35

Fire clay

10

10

Flint

10

20

Kaolin

20

20

30

35

10

10

20

10

30

10

10

15

Talc

Sample Clay body compositions (A–E)*

E

75 15

Nepheline syenite

D

25

25

Ball clay

C

Typical Stoneware compositions

Typical Earthenware compositions

A

A

B

C

D

Stoneware clay

30 80

75

40

30

Sagger clay

25

Ball clay

10

35 20 15

20

30

10

Red clay Feldspar Flint Fire clay

30 40

Kaolin

10

10

10

5 15 10

10

Sample Clay body compositions (A–E)* A

B

C

D

E

Georgia kaolin

30 35

25

25

5

30

Florida kaolin

25 10

15

35

40

15

5

10

25

E Typical Porcelain compositions

Sample Clay body compositions (A–E)*

English ball clay Kentucky ball clay Feldspar

30

30

25

Nepheline syenite Flint

15 10 20 25

20

20

25

20

20

*Parts per one hundred

30

Chart summarizing common base clay compositions.2

19

4 Automated clay body preparation in a high-volume production system.

The distinction between different clay bodies can be complicated, as the specific terminology differs to some degree according to the context in which the material is described. Material composition, part performance, density, plasticity, color, and firing range are all considered when distinguishing materials in their contexts. In the architectural discourse, particularly in historical contexts, the term terra cotta is often used to describe all architectural ceramics regardless of clay body, material performance, and other distinguishing characteristics. Often, color alone is mistakenly used to identify specific clay bodies, and it is common for all red or brown clay bodies to be considered terra cotta once fired, and all white clay bodies to be identified as porcelain. Color, however, is not a good indicator of clay type—white stoneware, for example, is quite common but should not be confused with porcelain. In the context of contemporary architectural ceramics the distinction is even more difficult, as additives and coatings can effectively disguise the appearance of the underlying part. Adding coloring agents can give the clay body almost any appearance, blurring any direct relationship to the base material (4). Maybe the most useful parameter for discussing clay bodies is the density and related porosity of the fired component (see also introduction to Chapter 10). Earthenware is less dense than stoneware, which in turn is less dense than porcelain. Density relates to the amount of water that can be absorbed by a fired part and therefore determines the absorption range of the unglazed ceramic element—the less dense the body the higher the absorption rate and the greater the porosity. Most low-density clays, when fired to maturity, do not vitrify and therefore are always permeable by water whereas clays of higher density can become vitreous and resistant to water infiltration. Water absorption in turn determines the resistance to freeze-thaw cycles. The ceramics industry today has a wide and growing set of additives at its disposal that can be incorporated into the clay body for a variety of reasons. This includes recycled ceramics, glass, or stone dust as discussed in Chapter 7. Many performance characteristics can be addressed by combining the appropriate clay body—typically a mix of clays, fluxes, and silica—with additives. Some additives improve material behavior during processing, particularly in craft and low-volume settings. The addition of nylon fibers, for example, increases the “green strength” of the dried clay before firing, thus facilitating the handling of delicate unfired elements. These fibers have little impact on the properties of the finished part because they burn away during firing. Other additives are specifically designed to affect the properties of the end product. Kyanite, for example, reduces thermal stress and increases mechanical strength in the finished product. Reinforcements such as basalt fibers or high-temperature steel fibers are being investigated, but have not yet reached commercial maturity.

MATERIALS AND MATERIAL PROPERTIES

5 The results of differential shrinkage and part geometry. Here, forces concentrated at the corners of the part lead to undesirable results.

Shrinkage Once the clay body has been formed into an element, it dries to the “green state”— either naturally or through machine-based, more controlled drying processes. During drying and subsequent firing, shrinkage occurs as moisture is removed. From a design perspective, it is important to understand the relationship of clay body to shrinkage. Raw material properties such as particle size and moisture content impact shrinkage rates: the smaller the particle size and greater the moisture content the higher the shrinkage rate. All clay shrinks, but while this may be straightforward when considering flat parts where simple oversizing can compensate for dimensional change, formally complex parts can be problematic. A deeply curved part dried on a convex mold, for example, may be more susceptible to cracking, while drying the same part on a concave mold may result in a successful part (5). Shrinkage rates vary between clay bodies from approximately 8–12%. Two stages of shrinkage can be distinguished. First, approximately half of the overall shrinkage occurs during drying when moisture evaporates from the surface, drying the clay from the outside in. Water moves from the center out through capillary action. This causes “differential shrinkage”, which can result in warping and even cracking as outer surfaces dry faster than the core material. Drying can be highly controlled, often using specialized equipment, and by ensuring that all sides of the part dry uniformly by supporting the parts in a way that avoids warping and sagging. Additional shrinkage, typically 50% of the overall rate, occurs during firing when particles are sintered or bonded together and all remaining chemical moisture is released from the clay body. Shrinkage during firing impacts all clays and clay bodies but tends to be much less in dry-processed parts compared to plastic-processed parts, again due to initial moisture content and particle size. Deformation or warping is also possible during firing and is typically accounted for in part design (explored in the case studies later in this book), kiln positioning, and the use of removable support structures that hold cantilevering or unsupported areas (6). The most common method of addressing shrinkage is to scale up parts to match final desired dimensions. It is often possible to dimensionally rectify parts after firing (by grinding, cutting, etc.), but there are costs involved in this additional step. Today’s material and fabrication knowledge allows for fairly precise dimensions,

21

6

Diagram of geometric features of an extruded stair tread designed to minimize potential failures and deformation during production.

yet tolerances remain and have to be considered in the detailed design for production phase when design teams need to work in close consultation with producers. Each production process inevitably comes with its own constraints and rules (see Chapter 4). Properties of Ceramic Parts Generally, ceramic parts are brittle, have a relatively high compressive strength, and behave poorly under tension. Bending strengths range between 7 MPa and 30 MPa for typical tiles to 120 MPa for high-end porcelain sinks. Typically, clay bodies fired at higher temperatures, up to 1,300°C, exhibit increased strength compared to those fired at temperatures as low as 1,000°C. Terra cotta, for example, does not exhibit the structural properties of porcelain. In most cases, the desired finished part properties drive the design of the clay body, but in others a clay body is chosen for its behavior during processing and part properties are manipulated during firing. Some producers might use a consistent stoneware clay body for their entire production but vary firing temperatures and firing sequence in order to control the strength or porosity of the ensuing product. Brittleness and vulnerability to crack propagation should be considered in part design and assembly detailing. Designers should avoid creating areas of high stress concentration, which include drastic changes in wall thickness, sharp edges, openings, localized fasteners (particularly those requiring perforations), acute corners, and non-filleted intersections. Vitrification becomes a critical consideration when determining finished part properties. A ceramic element that has been vitrified can resist moisture infiltration and therefore typically performs better in climates that undergo regular freeze-thaw cycles. When a part is not fully vitrified it remains porous, which can lead to spalling when internal moisture expands during freezing. Porosity, on the other hand, can be highly beneficial for applications that depend on moisture absorption, for example, when ceramic elements are used as evaporative cooling systems. Glazes Glaze is the primary material used to finish architectural ceramic elements, seal the surface to reduce wear, resist stains and dirt, and improve impact resistance. The design of glazes is a technical activity at all volumes of production (e.g., craftbased and industrial), usually balancing aesthetics and a variety of performance goals (7). Some artisans and chemists at industrial manufacturers develop proprietary glazes or glaze techniques beyond what glaze suppliers offer (8). Glazes are glass finishes primarily composed of alumina, silica, and a mix of oxide fluxes such as soda, potassium, and lime/calcium that reduce the overall melting points of the silica and alumina. Alumina, derived from clay and feldspar, increases the viscosity of the glaze and thus keeps it from running off the part as it fuses to the ceramic element during firing. Silica, the glass-forming component in glazes, primarily comes from flint. Most glazes also contain additional oxide fluxes that are used to modify the melting temperature of the glaze and control the coefficient of expansion (COE) of the glaze composition. Different from glass, which is typically mixed and formed into pellets, rods, and other stock shapes for later use in the production of glass products, glaze is applied to the ceramic surface as a mixture of liquid raw materials, and fused in place during firing.

MATERIALS AND MATERIAL PROPERTIES

7 Industrially produced ceramic elements are commonly differentiated with unique, often manually applied, glaze decorations. This strategy increases the value of manufacturing tooling by increasing variety in a single element typology.

8

Coloring oxide combinations IRON +

Cobalt Copper Manganese Vanadium Rutile Nickel Chrome

COPPER +

Cobalt Manganese Vanadium Rutile Nickel Chrome

MANGANESE +

NICKEL +

Vanadium Nickel

Resulting color grey-blue warm green, metallic green, black brown ochre ochre, brown brown to grey blackish green blue-green brown, black yellow-green warm or textured green grey-green green yellow-brown grey or brown

Rutile Cobalt Chrome

brown blue-purple brown

Vanadium Rutile

grey, brown brown

Cobalt Cobalt Chrome

blue-purple brown

COBALT +

Vanadium Rutile Chrome

greyed yellow or mustard textured warm blue or grey-blue blue-green

RUTILE +

Vanadium Chrome

ochre, yellow warm green

CHROME +

Vanadium

yellow-green

Glaze compatibility becomes a critical factor for ensuring that the COE of the glaze and ceramic base part are compatible. To ensure a durable bond, both must behave in a similar manner during heating and cooling. This is particularly important for roof tiles that are subject to extreme temperature fluctuations. Glazes have long been used to provide surface coloring. The complexity of glaze chemistry is exacerbated when color is considered. Color is typically created by the addition of oxides into the transparent glaze mixture. Multiple oxides are often mixed to create particular colors, and while only a limited number of oxides are used in glazing the range of colors is almost endless. Iron oxide is a common coloring agent, but is also regarded as an impurity in products where the desired outcome is white—sanitary ware for example. Environmental conditions (temperature, relative humidity, etc.) and process parameters (firing technique, kiln schedule, etc.), along with the composition of the clay body, have potentially dramatic effects on the color of the fired ceramic pieces (9).

23

Chart showing basic glaze compositions relative to color.3

9 In industrial settings, glaze colors are tested through a series of prototypical elements.

Colors of unfired glazes give no visual clue as to the color of the glaze once fired. In a craft-based production setting glaze colors can be slightly inconsistent across a single production run. These slight variations can be an asset for end-users who value a product that communicates direct involvement of craftspeople in the production. In high-volume industrial settings, by contrast, large production runs of a single color are created and any variation is seen as a flaw. In most processes involving glazes, test tiles or prototypical samples are made to ensure the glaze mix is consistent with expectations. Many automated factories have quality control systems in place that detect defects; others have people positioned along the lines to perform quality checks, or a manual random sampling from the line is removed and evaluated. A variety of glaze techniques are used to create surface texture and other aesthetic or performative characteristics (as described in Chapter 8). The level of nuanced control within current glaze technology is astounding and presents a wide range of design opportunities. A growing variety of tiles mimic other materials (wood, steel, copper, etc.), expanding the historical design of terra cotta facades made to look like stone (10). This trend continues today, stronger and more technically robust than ever. 10 Industrially produced ceramic tiles designed to mimic stone in appearance through the use of texture and glaze.

MATERIALS AND MATERIAL PROPERTIES

11 Pendulum testing apparatus at the Instituto de Tecnología Cerámica (ITC) in Castellón, Spain.

Other Surface Treatments and Coatings In addition to glazes, other surface treatments can be applied to enhance the performance of the ceramic element, such as slip, stain, and chemical resistance. Slip resistance, a fundamental characteristic of ceramics applied to public and wet environments, is of particular importance when considering flooring applications and is often created through a chemical treatment using hydrofluoric acid or ammonium bifluoride that is applied to the glazed surface. Slip resistance is tested in a variety of ways, most commonly using the Pendulum slip resistance testing device but also ramp testing and emerging tribometer technologies, which are becoming standardized to improve uniform testing guidelines (see Chapter 4). Often classification of slip resistance is based solely on the static coefficient of friction (SCOF), but others call for specifying a dynamic coefficient of friction (DCOF), which applies to bodies in motion and more accurately represents slip incidents. In the USA, recently established ASTM guidelines specify the use of an advanced tribometer (BOT-3000) to test DCOF on both wet and dry surfaces. Global standardized reporting and testing methods are still in development, so careful consideration is needed when specifying ceramics for flooring applications, and resistance to slipping should be considered in accordance with local building codes (11). Most surfaces are subjected to chemicals and other damaging agents through use and cleaning, but the need for enhanced resistance is most prevalent where harsh chemicals are common. Chemical resistance, an important consideration in industrial environments, is typically classified based on the porosity of unglazed tile, with the most chemical-resistant tiles having very low water absorption and resistance to acidic solubility. In addition to full vitrification, acid- and chemical-resistant glazes are created with the addition of calcium carbonate, titanium dioxide, and other compounds. Chemical resistance is tested based on ISO standard 10545-13, which addresses the ability of the glazed surface to withstand household chemicals, pool additives, acids, and solvents without degrading the appearance of the tile.

25

NOTES 1, 2, 3 Tables adapted from the book by Daniel Rhodes, Clay and Glazes for the Potter, originally published by Chilton Book Company in 1957, Literary Licensing LLC 2013. This book is a leading resource for ceramicists and potters.

CHAPTER 4

PRODUCTION PROCESSES

The production of ceramic materials involve a complex sequence of steps from upstream aspects such as material extraction and raw material preparation, to activities by ceramic manufacturers that involve the shaping of clay, glazing, drying, and firing of clay as well as post-processing and packaging; to downstream aspects such as distribution and installation (1). The first two levels of this process tend to be more local in character, while the downstream process of distribution is global. Unlike most construction materials, clay can be formed in a wide range of states, from dry powders to near-liquid slip, and in its plastic state can be formed without heat under relatively low pressure. This range of process options results in a uniquely versatile end product whose applications range from decorative mosaic tiles to bathroom appliances and large structural elements. Ceramic production can take place in settings that are entirely industrial or largely craft-based. Industrial ceramic manufacturers operate automated, high-volume equipment typically for mass-production of tiles (2). Craft-based production is characterized by manual operations and low-volume production of higher tolerance end products (3). Combinations of both settings have emerged as the most suitable environments for architects engaged in designing custom ceramic systems for facades, roofs, or interiors. This kind of project-specific customization requires part numbers in the thousands. It is related to, but not identical to, true “mass-customization” where varied, high-volume production enables individualized end products largely as unique combinations of standardized modules. The basic principles of production processes are independent of the actual setting, but important differences exist and will be pointed out in the text. For designers, the practical distinction between “wet” and “dry” production processes is perhaps the most relevant categorization when discussing options for the shaping of ceramic elements. This distinction has bearing on the production capacity (wet processes favor lower production volumes), dimensional tolerances, types of tooling used, and part costs. It is the best indicator for the ability of the designer to engage in the development of novel or individually customized ceramic building components. Nearly all production processes associated with architectural ceramics follow a similar sequence that includes the creation of the clay body, followed by shaping, drying, firing, post-processing, and packaging. As the level of industrial automation increases, several of these stages are combined. In the highest-volume production facilities, a finish material is applied during or directly after the forming process of the clay body. The resulting elements are dried if needed, then moved directly to the

1

2

Typical manufacturing workflows for architectural ceramic material systems.

Automated factories enable high-volume production with very little labor.

Raw Material Extraction + Preparation Clay

Raw Material 1

Other Materials

Raw Material 2

Material Suppliers

Finish

Clay Body

External

Ceramic Producers

Water

Clay Body Customization

Tooling

Shaping Processes

Grog

Waste Recovery

3 Waste Recovery

Drying

An artisan manually glazes a cast ceramic tile in a medium-volume production facility in Valencia, Spain.

Glaze Application

Waste Recovery

Green Kiln Firing

Bisque

Mature

Waste

Supplies

Waste Recovery

Waste Recovery

Post-processing

Packaging

Mature

Kiln Firing

Marketing

Storage + Shipping

Distribution networks Building Materials

Distributor

Contractor

Facade Fabricator

Industry Association

Installer

Installation at Construction Site

Waste

kiln, thus maximizing production efficiency. Key process variations will be discussed in the context of customization potential. Additional details can also be found in the case studies of chapters 8 to 12. There are few other industries where industrial manufacturers continue to co-exist with more nuanced, craft-based production methods. At the lowest end of production volumes are ceramic artists and potters who, on occasion, deploy their manual skills to create one-off architectural products. Intermediate production volumes involve a higher degree of worker specialization whereby some may hand-mold or extrude elements, others glaze them, and yet others oversee firing and other aspects. Many examples in the book, especially those relating to form customization and thermodynamic skins, represent the integration of manual craft with technologies typically encountered in high-volume production settings. These technologies include automated, even robotic glaze application systems, numerically controlled kilns, and computer-numerically controlled post-processing machines. Such hybrid production settings have the highest level of part customization potential by relying on craft-based strategies for some and automated systems for other parts of the production process. Often these producers are keen to work directly with design teams in developing project-specific ceramic systems. On the upper extreme of production volumes are tile manufacturers that operate large production lines where forming, finishing, and post-processing of clay are automated with little to no need for

27

human intervention. Robotic technologies are used routinely to improve productivity. Changes in what is being produced must be minimized to avoid costly equipment downtime during setup. The majority of flat tiles are produced in these environments. Any type of production setting relies on a controlled preparation of clay, additives, and glazes. Preparation of the clay body involves drying and grinding processes such that the desired particle size of approximately 0.01–4 mm is accomplished. In the highest-volume production facilities, the raw materials are often prepared on site (4). In others, pre-mixed clay bodies are supplied to the factory from a distributor. In most craft-based studios it is a supplier who mixes the clay bodies, but it is not uncommon for individual ceramic artists and potters to develop their own custom mixture based on desired material behavior and part properties. In some cases, producers have an established clay body, or collection of clay bodies, that are used for all projects. Companies capable of project-specific custom production often modify their standard clay bodies to meet performance requirements for a project. Dry-pressing A single dry process, pressing, is used to produce the majority of flat or slightly textured ceramic tiles. Industrial dry-pressing is a highly automated process whereby a precisely calibrated, powdered clay body with a moisture content between 3 and 7% is pressed under high, evenly distributed pressure of up to 10,000 tons in a steel mold. Manufacturers deploy substantial hydraulic presses that provide high-precision molding at elevated production speeds, often outputting multiple tiles per second. Air pressure can be used to rapidly release the pressed clay powder from the mold (5). In some cases, pressed elements have a full-body composition, i.e., the unit remains homogenous throughout the entire thickness. In other cases, such as double-pressing, glazes and other higher-value materials with better finish or performance characteristics, such as slip resistance or textures, are applied to the finish layer of the unit, resulting in a stratified finish and body. Due to high tooling costs of the steel molds, dry-pressing is reserved for high production volumes and offers little opportunity for formal customization except through cutting after firing.

4

5 Automated clay body preparation, reserved for the highest production volumes, ensures product consistency. Here, a numerically controlled machine distributes materials for dry-pressing.

6 An automated grinding machine performs incremental dimensional rectification and polishing of finished tiles.

PRODUCTION PROCESSES

Hydraulic presses are used for most dry-pressing operations.

7

8

Clay Body

Continuous glazing occurs during high-volume production. Here, the waterfall glazing technique is applied to pressed tiles in a factory in Valencia, Spain.

Pressed Tile

Diagram of dry-pressing process. 9 An automated extrusion line produces stair treads in a factory in Castellón, Spain.

Dry-pressing is a precision process and tolerances tend to vary with product cost— cheaper products tend to display a slightly higher degree of variation whereas more expensive units achieve precision through dimensional rectification after firing (6). Flat tiles make up the majority of pressed tiles and most have a slightly filleted edge. Slight thickness variation can be achieved in the pressing process and low-relief parts can be made (7). Most pressed tiles are glazed on one side by passing through so-called waterfall glaze modules that are integrated into the production lines (8). Tiles are then dried and fired in automated roller kilns with precise control over temperatures at each stage of the firing. Such production runs achieve great uniformity in format and color. In many cases a manufacturer will offer a single-format tile but in a wide range of colored or textured glazes. Textured finishes can be created during the automated process through a combination of glazes and textured applicators. Within the pressing process, finishing offers the most opportunity for design intervention and in some cases customization may be possible. Advances in finishing techniques, including digital inkjet printing discussed in the Products and Technologies section at the end of the book, offer the potential for low-volume customization and, through digital interfaces, are relatively accessible to the designer and client. Pressed ceramic elements can be cut after firing to create unique shapes. Edge grinding can further reduce dimensional tolerances for high-end products. Pressed tiles can be shaped through slumping techniques during a secondary firing, sometimes aided by locally weakening and scoring tiles. This process is often utilized to form matching trim details such as stair treads and column covers (see Chapter 5). Extrusion Extrusion is a “wet” process used to form clays with a moisture content of 14–22%. During extrusion, a large lead screw system forces clay through a vacuum chamber and eventually through a shaping die in a continuous fashion, resulting in linear parts that have a consistent cross-section throughout (9). A typical extrusion line has a single work cell or machine that receives a clay body, mixes, de-gasses, and shapes the material onto a continuous conveyor or roller system. Once shaped, the material

29

10

Mixing

Diagram outlining the typical extrusion process.

Waste

Clay

Vacuum

Extrusion die Cut

Clay element

is cut to length using an automated wire or blades that move perpendicular to the axis of extrusion. Extruded parts typically undergo two firings: the first creates consolidated green-ware and the second bonds glazes or other finish materials to the final part while achieving full sintering (10). Extrusion is a primary shaping process where the part leaves the die in a final cross-sectional shape. In some cases additional features are added to unsupported areas for the sole purpose of insuring that complex units retain their shape without warping. This additional geometry is broken away either through manual or automated processes after the final firing stage (see also the case study on the Zaragoza Expo Pavilion in Chapter 10. Industrial clay extrusion is a medium- to high-volume manufacturing process that, compared to dry-pressing and despite its linear nature, offers better potential for shape customization. Extrusion dies are cut from plate steel and made to withstand the substantial pressure of wet clay pushed into the die (11). Producers extrude standard floor or wall tiles in addition to special elements such as stair treads. A medium production volume, in the thousands of parts, is typically needed to offset the costs of designing and making the dies. Most companies that specialize in working with architects to develop and produce custom facade elements deploy extrusion processes in their production. Craft-based extrusion exists as well, but is used to a very limited degree in buildings. It is often a manual process using a vertical extruder and much lower pressure. The resulting elements are considerably less accurate than those produced in the industrial process. Custom extrusion dies can be easily produced with very low tooling costs using wood, metal, and other materials. For an example of architectural applications of manual extruded elements see the Kosemo Brick case study in Chapter 11. Extruded parts tend to exhibit higher shrinkage rates that often result in slightly higher dimensional tolerances compared to dry-pressed pieces. Extruded tiles are thicker than their dry-pressed counterparts. Many parts created through extrusion are considered one-sided, with a finish surface and a hidden surface, but some producers are able to create parts with high-quality surfaces on all sides, which is common in the production of shading lamella and baguettes (12). The production of non-flat shapes often requires a secondary support structure that is included in the design of the extrusion of the individual part. When the support structure is removed after firing, it leaves a slight surface defect on the hidden side of the piece (13). In many architectural applications extruded parts are molded with embedded detailing such as slots and grooves. These features eventually allow the element to hook into metal substructures during installation. Extruded parts can be cut or ground after firing to mediate dimensional variation due to shrinkage, or to make provisions for special attachment systems.

PRODUCTION PROCESSES

11

12 Extruded shading baguettes produced by Boston Valley Terra Cotta as part of their standard product line; shown here on the McGee Pavilion at Alfred University designed by IKON 5 Architects.

Extrusion die used in medium- to high-volume production at the NBK Architectural Terracotta factory.

13

14 Supporting features in the extruded stair tread are removed during automated production after firing.

Secondary molding processes are applied to extruded elements to create specialty components and non-flat elements.

Extrusion is also used to create the base stock for other forming processes such as slumping, pressing, or die-cutting. In these processes a homogenous slab of a desired thickness is extruded and a subsequent secondary process is applied to create a final shape. Slump Forming/Slump Molding Slump molding is a “wet” process used to create low-volume or even one-of-a-kind components by forming a relatively soft clay slab or other element over a mold. In the industrial context the clay element is extruded, cut to size, and placed over the onesided mold. This is the typical production sequence for producing curved pieces for ventilated facades made of extruded ceramic elements (14). The process is largely manual and mold materials range from plaster and wood to expanded polystyrene foams, which in architectural applications represent the lowest tooling cost for custom applications. As a craft-based process, slumping requires few specialized tools and is suitable for production of single to tens of parts. The process is common also for use with extruded flat slabs that can be slumped into three-dimensional forms. Final dimensioning and shaping of the slabs can occur prior to molding or after the clay has been placed on the mold. In ceramic studio environments, slabs are not extruded, but instead are rolled using a manual slab roller or hand-held rolling pin. Typically, industrially extruded clay slabs have a lower moisture content than those rolled out manually; therefore, parts generally exhibit lower dimensional tolerances and more predictable behavior during the drying and sintering processes. The case study of the Villa Nurbs in Chapter 11 is an example of slump forming. Kiln-based slump molding is a different process used to create curved elements, trim details, and special components from previously fired flat ceramic parts. By returning the previously sintered component to the kiln for secondary processing the fired ceramic can be softened just enough to allow for plastic deformation to occur without losing its surface quality and dimensional accuracy. In slump molding the sintered part is scored using a grinding machine or placed on a mold within the kiln. When fired the unit deforms to take the shape of the mold.

31

Parts formed through slump molding exhibit similar mechanical properties as parts shaped during the primary forming process. Kiln-formed parts shaped using the scoring methods are weaker along the score line than their flat counterparts because of an overall reduction in cross-sectional area. The base stock used in slumping is often trimmed to a final shape or dimension before forming takes places; thus part edges are often normal to the surface of the unit, making non-tangent installation problematic without specific consideration. Typically slump-molded processes require a large minimum radius (relevant for column covers) whereas kiln-formed parts made through scoring can take on relatively small radii (as required for stair treads or wall-floor transitions). Where wet clay is applied to a mold, sharp angles or tight curvature often result in increased stresses where the material changes direction. This variation can lead to cracking during the drying process or deformation during firing. In cases where a second firing is used to form the part, a relief cut is often made to limit the accumulation of stresses and enable precise bending of the part. Die-cutting In a typical die-cutting process a continuous and rectangular clay slab is extruded and a finished shape is cut using a vertical, steel die-cutting tool. Normally the cutting operation is directly incorporated into the extrusion line. Die-cut extruded tiles are often produced in a volume between dry-pressing and hand-made wet molding, opening an opportunity for the production of a medium-volume run of custom units (15). As with most extrusion processes, the surface of the clay is oiled prior to cutting to avoid sticking. Once a piece is cut, the remaining clay is returned to the extrusion line and reintroduced in a near-zero waste production process. Parts produced using die-cutting have slightly filleted edges resulting from the cutting operation. 15 Hexagonal tiles are die-cut from an extruded slab during a hybrid production process.

Plastic Pressing Plastic pressing is a forming process involving a double-sided mold and a clay body with a moisture content of 14–22%. A clay slug or slab is placed in the mold and formed under pressure. The relatively low mold pressures required for plastic pressing allow for the use of inexpensive pressing tools often made from gypsum, thus lowering tooling costs and rendering the process suitable for low-volume production and part customization. Plastic pressing can produce high-relief parts difficult to generate with extrusion techniques alone. Like all molding processes, plastic pressing requires strict adherence to process constraints. Parts have to be designed with proper draft angles often larger than 2˚. Each press environment will have a maximum depth and minimum feature size. Variations in wall thickness should be limited to reduce stresses during drying and firing (16). Plastic pressing is suitable for low- to high-volume production of architectural ceramic components.

PRODUCTION PROCESSES

16 Diagram of plastic pressing processes. Mold Mold

Clay element

Clay Mold Mold

In an industrial setting, plastic pressing is largely automated and often used for the production of roof tiles. In these production settings, multiple parts are pressed simultaneously using large molding machines or gang-presses fitted with multiple molds. After pressing, each part is continuously supported during firing to avoid any deformation. Once fired, units are stacked and groups of tiles continue their way through the production sequence. Similar to dry-pressing, the state-of-the-art plastic pressing facility is fully automated, from the mixing of the clay body to the packaging of the finished product. As is the case with most production processes, the opportunity for customization decreases with the increase in industrial automation. In the context of high-volume industrial production, surface finish is the key (and the only) opportunity for design intervention on the product level. However, plastic pressing is also suitable for low-volume production, and within this context offers a high level of customization potential. Some producers keep plastic presses in their facilities catering to very small production runs for specific projects, and others produce specialty roof tiles to match historic models. Clay may be prepared and placed by hand, and the stamping machine can even be manually operated. For additional details see the case study of the Aichi Pavilion discussed in Chapter 11. Slip Casting Slip casting is a process involving a near-liquid clay slip (casting slip). It can be discussed as two distinct processes. First, solid slip casting is a molding process whereby a clay slip is poured or injected into a mold and allowed to dry throughout as a solid part. In the second instance, hollow slip casting, a clay slip is poured into a larger mold and allowed to dry out and consolidate only adjacent to the interior mold surface. The duration of the drying process determines the wall thickness of the end product. The remaining slip is drained from the mold leaving a hollow part. Solid slip casting is less common in industrial settings and rare in most craft-based scenarios. Hollow slip casting is common in the industrial production of sanitary ware and heavily used in craft-based settings for a wide variety of parts (17). 17 Slip

Trim

Clay element Slip

Diagram showing a common slip casting process.

33

18

19 Industrial slip casting of sanitary ware at the Laufen ceramic factory in Laufen, Switzerland.

Large-format, lowvolume slip cast architectural detail for the Sagrada Família by Antoni Gaudí. The glazed part is displayed in its mold at the atelier of Ceràmica Cumella.

20 Photomontage of a two-sided slip-casting process and the resulting ceramic element produced by designer Jonathan Grinham.

Both variants of slip casting can be used to create extremely complex geometries through multiple-part molds (two-part molds are usually considered the minimum) or the merger of many molded parts. For example, the Western toilet, arguably the most geometrically complex (and least talked about) architectural element produced in significant volume, is created through multiple slip casts joined together while still in the plastic state to become a singular unit once fired. Slip casting is suitable for a wide range of elements and enables remarkably complex internal and external geometries (19). Pressure casting, a variant on the slip casting process, involves the molding of slip or slurry under pressure. Pressure casting is utilized to produce detailed parts by some producers of sanitary ware. Both craft-based and industrial slip cast productions utilize plaster molds, but special foams can also be used for highly industrial applications. In the studio environment the mold is often created from a positive or male pattern and used for a small series of pieces (20). During industrial operations a plaster mold is used until it becomes overly saturated or worn and is then replaced. Typical plaster molds can only be used approximately 100 times for slip casting. In high-volume production settings a series of tools, made of stainless steel or a range of polymers, are used to efficiently create new plaster molds. This process represents one of the rare operations in ceramic material systems where the creation of tooling is embedded in the production cycle. Often, a mold or die outlasts its production uses and is stored in the factory for reuse at a later date.

PRODUCTION PROCESSES

21

22 Wheel-throwing workshop at the Harvard University Office of the Arts Ceramics Studio.

A collection of wheelthrown vessels created by artist Trew Bennett of Buck Creek Pottery incorporates strategic asymmetry to accentuate the relationship of the rotational wheel and the hand of the artist.

Wheel-throwing The potter’s wheel is not typically used in the production of architectural ceramics. Wheel-throwing is a ubiquitous process used at varying levels of automation throughout the world, and represents one of mankind’s first manufacturing machines. It is different from all other production processes described in this chapter because the majority of these processes deploy tooling to give final shape to the clay, whereas wheel-throwing is a technique relying on the hand to create forms. The outcomes, therefore, tend to have higher tolerances in like parts (21). The potter’s wheel is used to create rotationally symmetrical objects such as vessels and requires trained skill to master. During wheel-throwing a clay ball, or wedge, is centered on the spinning wheel and shaped by hand or with manual tools to a desired form. The thrown (or turned) piece is often post-processed using a variety of manual techniques, and asymmetrical accessories, such as handles, can be added. While wheel-throwing inherently creates symmetrical parts, some artisans do use the wheel to create controlled asymmetry (22). Jiggering Jiggering is a rotational process, similar to wheel-throwing, that employs a Jolly or Jigger (mold) and a contoured template to form repetitive rotationally symmetric parts. It is often used in the production of whiteware. During Jiggering, clay is placed on a rotating mold that forms the interior surface of a part. The final shape is formed when a two-dimensional contour or profile is placed at a distance away from the mold, thus distributing the clay around the mold in a uniform thickness. Jiggering has a relatively high degree of repeatability and can be used to create a variety of complex geometries. This process is employed in craft-based settings but was developed, and is often used, in high-volume production of tableware such as plates, bowls, saucers, etc. Jiggering is not often used in the production of architectural elements but does present the opportunity to create custom parts with relatively low tooling costs and consistent results. Firing and Kilns In order for clay to become ceramic it must be fired. This process is generally considered as the first deliberate human activity that created a new material. Each of the processes described above involves firing, and in some cases multiple times, to achieve the desired end result. Firing is responsible for the majority of embodied energy of any ceramic element (see Chapter 7). The flexibility of kilns to process more than one type of product decreases with their processing capacity. In craft-based settings, kilns have significant flexibility and can be modified to accommodate a variety of shapes and sizes. Tunnel kilns, on the other hand, are used in high-volume tile production and are only suitable for this particular type of product.

35

Small static production kilns range in capacity from 17–600 liters for small electric kilns to up to 6,000 liters for gas-fired variations, including car- and shuttle-type kilns that are also used in lower-volume industrial processes. Kiln construction is relatively consistent, with each manufacturer introducing slight nuances in design, construction, and materials. From the inner volume, which is left open to be individually configured for each firing, walls are made of a refractory “fire brick” and accommodate a heat source. For electric kilns the heat source is a collection of heating elements embedded in the refractory material around the perimeter of the kiln. Gas kilns distribute heat through a combination of forced air and a series of jets that supply fuel to the flame used to heat the kiln. Some form of heat-resistant cladding, usually sheet metal whose primary function is to protect the “fire brick” from damage, wraps the refractory material on the outside of the kiln. Typically a ventilation system ensures consistent heat distribution within the kiln and eliminates potentially toxic off-gassing that may occur during firing (23). In addition to factory-made kilns, ceramicists also create custom kilns that respond to a particular artistic desire, often relating to specific finish qualities. One example is the Anagama, a traditional Japanese kiln consisting of a single chamber that is used to fire the ceramic pieces (24). These kilns are typically very large and wood-fired over a series of days. Wood-fired kilns typically produce a very specific surface character caused by fly ash and reactions during firing that change with many environmental parameters and the kinds of wood used during firing. Anagamas can range in size and can be used to fire large-format pieces. Unlike electric and gas kilns, these often room-size kilns are usually fired infrequently following up to a year or more of production. The distribution of firings and the intense labor involved can lead to community events surrounding each kiln run. 23 A reduction car kiln in use at the Harvard University Office of the Arts Ceramics Studio.

24

25 An Anagama firing at Buck Creek Pottery in Nelson County, Virginia, USA, fires an entire year’s production in a single firing.

PRODUCTION PROCESSES

Industrial roller kilns in a high-volume production facility.

Roller kilns and tunnel kilns, often supported by a range of automated or even robotic material handling systems, are used in high-volume production lines and are suited only for particular applications. For example, a factory that was configured with firing technologies for the production of flat tiles would not be able to transfer to the production of bricks without completely retooling its kilns. Industrial tunnel kilns such as those used in high-volume tile manufacturing are expansive, often spanning the entire length of a very large factory. High-volume industrial kilns are distinct in that the ceramic elements travel through a network of firing zones rather than remaining static during an entire firing cycle (25). The process of firing is a complex balance of heating and cooling, regulated by a kiln schedule that must be precisely controlled to achieve relatively predictable results. As production volume increases so does the level and sophistication of kiln control, with the largest factories utilizing entirely automated computer-controlled systems to operate their industrial kilns. In these systems each firing module within a long kiln is kept at a constant temperature, and kiln schedules are managed by the speed at which the ceramic elements move through the kiln tunnel to achieve the desired firing temperatures. In non-linear kilns the ceramic elements remain in the same location (inside of the kiln) for the duration of the full kiln schedule, which in some cases causes a production bottleneck that can inhibit production speed. Such kilns are common for smaller producers. A typical kiln schedule consists of a ramping-up period in which the temperatures inside the kiln—and of the ceramics pieces—are slowly brought from room temperature to the final firing temperature, or cone, required by the specific clay body. Cone is a term that refers to the pyrometric cone, which is used to verify temperature reading during firing cycles at various spaces in the kiln, with each cone melting at a prescribed temperature (26). Following the ramp phase, the pieces remain at a constant firing temperature for a prescribed duration, then enter a controlled cooling cycle, often much longer than the ramping period, in which the ceramic element returns to room temperature. Kiln scheduling is used to minimize part deformation and ultimately reduce the degree of thermal shock on the fired parts. Rapid temperature fluctuation, which might occur if the lid of an electric kiln is opened at peak temperature, may result in cracking or catastrophic failure within the ceramic pieces. In most contemporary kiln installations some level of digital control is included, but when necessary the kiln schedule can be controlled by observational methods (27). 26 Pyrometric cones deform at a given temperature and are used during firing to ensure proper sintering. The cones here are shown before and after a Cone 10 firing.

37

27 1.300 C

A diagram of an example kiln schedule for an industrial roller kiln used to produce porcelain elements. Here individual thermal zones or kilns within the continuous linear assembly control ramping, sintering, and cooling.

1.200 C 1.100 C 1.000 C 900 C 800 C 700 C

Vitrification

600 C 500 C 400 C 300 C 200 C

Kiln zone

100 C Ceramic Elements 1

2

3

4

5

6

7

8

9

10

11

12

13

14

15+

Glazing In medium- to high-volume production processes, glaze is usually applied as part of the automated production line. A variety of processes are used, but often glazing involves a continuous curtain of flowing glaze that coats the ceramic elements as they travel through the production facility (waterfall glaze modules). Spraying, both automated and manual, is also utilized. Automated robotic spraying processes are utilized by some factories and producers of sanitary ware, facade components, and other geometrically complex parts. Additional finish features can be incorporated while the glaze is wet. These include textures and other patterns that, on high-volume production lines, can be created through a series of rollers that imprint the surface of the glazed tile (28). In some cases workers apply glaze through manual spraying, and it is not uncommon for glazes and details to be manually applied in an artisanal manner with brushes or sponges. The state of the art in glaze technology utilizes high-resolution inkjet processes to direct-print pigments onto tile surfaces. These systems are utilized in medium- to high-volume production environments where tiles are produced to look like other materials. Wood grain or stone textures, for example, can be printed on the surface of the tile. In some cases custom printing services are available and nearly any image or graphic can be printed on an otherwise standard tile. These technologies will be discussed in detail through case studies in Chapters 8 to 13. Post-processing In the industrial context some ceramic products undergo a variety of post-processing operations. For high-end products, dimensional rectification is often performed through grinding or cutting of the edges. Here, fired ceramic parts are passed through a series of incremental grinding machines that use diamond wheels to remove material along the edges. Rectified parts have a square, chamfered, or tapered edge and can be installed with minimal grout lines. In some cases, surface polishing also occurs in a similar incremental manner. Additional post-processing includes secondary shaping, drilling, and cutting processes that are used to create specialty components, accommodate fasteners, and satisfy assembly and installation needs. In most adhered applications, cutting is done on site, but in facade applications parts are usually preconfigured in the factory, taking into account any specialty condition without need for modifications on site.

PRODUCTION PROCESSES

28 A series of rollers are used to create textured glaze effects during the production of ceramic floor tiles.

29 Automated systems, like this one in Castellón, Spain, are utilized in mass-production environments for storage and logistics.

Packaging and Distribution Distribution logistics vary relative to production volume. In the most sophisticated high-volume production settings—primarily large tile producers—packaging is automated and industrial robotic work cells package tiles in cardboard boxes before automated transfer devices take them to a robotic storage warehouse (29). Using bar codes and RFID tags, these automated warehouses employ pick and place robots and similar technologies to assemble custom shipments, readily and automatically palletized, for distributors (or occasionally a producer’s own network of resellers) across the world. International distribution networks bring tiles from the producer to distributors who then supply stores, showrooms, and ultimately installation contractors, other end-users, and consumers. Some elements may ship to fabricators that incorporate ceramic products in prefabricated elements for facades or roofs. As the overall number of like units produced decreases, the level of manual labor involved in packaging increases. In low-volume craft settings, but also in some relatively high-volume production facilities, much packaging and palletizing is still done manually. Producers specialized in custom ceramic solutions for building envelopes typically package project-specific deliveries manually, possibly assisted by mechanical lifting devices. These ceramic elements ship directly to facade contractors charged with assembling the elements into a functioning ceramic construction system, often involving some pre-assembly off site and eventually installation on site.

39

CHAPTER 5

APPLICATIONS: INTERIORS

Ceramic systems are designed and produced for an extremely wide range of building and landscape projects. Each application has its own constraints and opportunities requiring different combinations of clay body, firing, and glaze. Installation procedures vary as well. Product design, selection, and installation relate to the governing building codes and standards for specific locations, and reflect broader building cultures with their specific installation practices. This chapter provides an overview of the state of the art of interior ceramic systems, emphasizing typical industrial products that are widely available. However, the guidelines and issues presented are equally relevant for custom ceramic solutions as covered in Chapters 8 to 11. Emphasis is on overarching principles and fundamental technologies that apply across national and geographic boundaries, with references occasionally made to the code context of Europe and the USA. Adhered Tile Systems Maybe the most obvious interior application for ceramic systems is the ubiquitous tile used to produce robust surface finishes on walls and floors. These are among the oldest known applications of ceramics in buildings, allowing for a wide range of colors and surface effects and, lately, photorealistic imitations of other materials such as wood or stone as well as individualized graphic ornaments. Smaller tile formats can easily be adhered to complex surfaces such as in the library in Pécs, Hungary (1).

1 Colorful ceramic tiles cover the complexly shaped surface of the Beehive project, a regional library in Pécs, Hungary, by architects Török és Balázs Építészeti Kft.

These surface coverings consist of tiles adhered to rigid support surfaces, with grout filling the small gaps between them. Mechanically connected tile surfaces are also available—albeit to a far lesser degree. Durability, ease of cleaning even according to hygienic standards, and overall robustness are among the key advantages that make tiles attractive as a surface finish. Ceramic tile is usually classified according to a combination of size and fabrication method. Dry-pressing and extrusion, the most common production methods, result in tiles that range from 12 × 12 mm to approximately 450 × 450 mm. Small tiles in the order of 12–50 mm, usually referred to as mosaic tiles, are typically factory-adhered to a mesh to speed up installation. The overall mosaic tile element to be installed measures around 300 × 300 mm (2). 2 1.500 mm

Wall tiles come in a wide range of sizes from 12–3,600 mm edge length. Rectangular forms and many other shapes are possible.

3.600 mm

The other extreme is seen in recent trends towards much larger tiles with sizes of up to 1,500 × 3,000 mm or similar, and thicknesses of only 3–5 mm! These products often have glass-fiber reinforcement laminated to the back side or in between two outer ceramic layers, augmenting strength and stiffness properties. These thin tiles can be used as laminated surface covers for furniture, like the outer layer of countertops, or as wall and floor finishes. The extreme thinness allows many of these products to even be installed in single-curved configurations. Tests by the authors showed that radii of single curvature can approach 3 m for 3-mm-thick tiles. These products can also be used to tile over existing tile surfaces without adding significantly to the overall thickness of the floor finish, speeding up construction for refurbishment projects significantly. With a bending strength of approximately 50 N/mm2 these thin elements can even be used for facades with their common wind loads. Tile formats are commonly square and rectangular, but also include many special shapes and patterns. The vast majority are flat, but deeper, contoured, and profiled designs are available and can—in their interplay with light—produce interesting textured surface effects. The backs of all but most large-format thin tiles are textured in order to allow for a better bond with the adhesives or mortars used to connect them to their substrates. Most product lines include special configurations such as a bullnose or double bullnose for edges, as well as cove shapes or special base models for wall-to-floor transitions. Windowsill tiles, also referred to as step nosing, are designed to cover horizontal or moderately inclined surfaces while properly guiding water down (3). Such three-dimensional tile shapes are either wet-pressed or extruded. An overview of US and European standards1 for tiles is shown in (4). Typical, drypressed tiles are between 3 and 11 mm thick, while extruded products are thicker at 10–20 mm and more. Typical dimensional tolerances for flat tiles are 0.5 and 2% in overall size and flatness, and 5–10% in thickness.2 The width of the grout lines relates directly to the dimensional tolerances—grout lines between 1.5 and 6 mm are commonly used, with 3 mm being a typical dimension for many residential surfaces made from industrially produced, dry-pressed tiles. The norms contain many other restrictions.

41

3

Special pieces are made to cover corner conditions as well as many other applications.

4 Minimum Breaking Strength [N]

Europe

USA

US Group (ANSI A 137.1)

Absorption Rate by Weight [%]

Impervious Tile

< 0.5

Group Name (DIN EN 14411) Ia

Typical Firing Temperature [°C]

Minimum Breaking Strength < 7.5 mm [N]

Minimum Breaking Strength >= 7.5 mm [N]

Bending Strength [N/mm^2]

1200–1300

600

1.300

28 / 21

1150–1300

600

1.100

23 / 18

600

950

20 / 11

750

900

17.5 / 8.0

600

600

0.5

average 1.110 individual 1.000

Vitreous Tile (0.5–3 %

1 2

Ib

3 4 Semi-Vitreous Tile (3–7%)

5

IIa

6 7 8

average 1.110 individual 440

Non-Vitreous Tile (over 7 %)

9

IIb

10 > 10

III

Tile classifications in the USA and Europe. Bending strength values are minimum values.

950–1150

8.0 / 7.0

test: 3 linear bar bending first number: minimum average, second number: minimum individual value

test: 4 point bending

When selecting tiles for use on interior surfaces, water absorption, wear resistance, and slip resistance for floor tiles are among the key functional properties. Water absorption is especially important when full-body, unglazed tiles are to be used in wet environments, or when wet cleaning methods are expected. Unglazed terra cotta tiles tend to be the most porous and absorbent, whereas porcelain and stoneware are denser and less absorbent. Chemical resistance can be important for applications in labs and kitchen environments. Slip resistance is crucial for all floor tiles. The precise requirements depend on the application domain with its typical contaminants (e.g., oil or chemicals for industrial uses, water for residential uses) and typical shoe soles worn by the occupants. Choosing a product with better slip resistance usually compromises the degree to which tiles accumulate dirt. Tile size—and with it the number of mortar joints—also influences how slippery a tile floor will be. Joints almost always create a slight roughness with inevitably better friction. Here again the needs of maintenance—mortar joints tend to be less stain-resistant and may allow water to penetrate—and slip resistance need to be balanced. There are several tests to measure slip resistance, but their results, unfortunately, are not always consistent and cannot be easily compared. For on-site use a common procedure is a skid-resistance test using a pendulum device (5). The instrument includes a heavy pendulum that decelerates as its rubber head—simulating a shoe sole—rubs along the tile surface.3 The degree of deceleration gives an indicator of slip resistance. Electronic instruments that measure friction coefficients directly are available as well. A common laboratory test involves a variably sloped ramp and an actual test person walking down the ramp until slippage occurs.

5 A pendulum test of slip resistance can be carried out after the tiles are installed. The microscopic images shows the surface roughness of a flat glazed tile with medium surface roughness.

APPLICATIONS: INTERIORS

6 Tile installation relies entirely on the tile setter’s skills. Each element is carefully set in the troweled mortar or adhesive bed. Once the adhesive has cured, the joints are grouted and the tile surface is cleaned with a sponge.

Tile installation is labor-intensive, relatively time-consuming, and a significant aspect in the overall cost of tile surface finishes (6). This is in part why large tiles with shorter installation times have become more attractive. Installation of adhered tile surfaces involves viscous adhesives applied onto a rigid base surface. In areas of high-water exposure an additional membrane—often using polyethylene—or liquid waterproofing layer may be needed as well. Adhesives include relatively flexible latex-based products—primarily for residential or light commercial use—cement mortars in thin or thick bed methods, or epoxies. The choice of adhesive depends on the quality and evenness of the base substrate, the clay body of the tile—more absorptive ceramics, for example, may require dry-set mortars—and the degree of exposure to moisture and chemicals. A new approach to adhesion-based tile installation is the use of adhesive-coated meshes that are dry to the touch and permit tiles to be rapidly installed. The degree to which this system stands the test of time remains to be seen. Once tiles are adhered and the adhesive has dried, joints can be grouted. Grouting materials, along with the tiles and the adhesive, complete the construction system.4 Cement-based (sanded and non-sanded) grouts as well as acrylics or epoxies are available. Choices depend on the width of the grouted joint and requirements on the tile surface. Highly absorptive, unglazed tiles, for example, are difficult to use with acrylic grouts, as grout residues are hard to remove from the surface. Grout colors need to be chosen carefully to either match or contrast the tile colors. Overall color impressions are quite dependent on grout color, especially when designing surfaces with mosaic tiles. Mechanically Connected Tiles Dry installation systems for interior flat tile surfaces have emerged more recently. Mechanical connections were developed in response to the laborious adhesion process on site, and to allow tiles to be reused in environments where frequent remodeling is expected—such as office buildings. Raised floor applications are one example of mechanically placed tiles. These use thick tiles directly placed on a raised substructure, or combine tiles bonded to rigid boards that in turn rest on fixed or height-adjustable feet. Additional beam elements sometimes support the edges of these raised elements. Interior applications for raised floors are primarily office buildings, but also short-term applications such as trade fair stands and similar spaces. Installation time is much faster compared to adhesion systems, and tile floors are ready to use immediately once the tile has been placed. Ease of disassembly can be an advantage if end-of-life scenarios for tiles are considered (7). Research in the use of elastomeric interlayers between tiles and rigid subfloors is being conducted but has yet to result in a marketable product. The interlayer replaces adhesives, and a gasket between tiles maintains their proper spacing (8).

43

7 Mechanically placed tile for a raised floor system. The absence of adhesives allows easy reuse in office environments that tend to change space layout frequently.

8 The prototypical tile system for dry installation features specially contoured tile edges that match an elastomeric gasket for a tight fit between tiles.

Mechanical connections can certainly be used on interior ceramic claddings adapted from systems developed for exterior envelopes, as for example in the National Museum of American Jewish History in Philadelphia, Pennsylvania, USA, by New York-based Ennead Architects. Here a single system was actually used throughout, but gaskets were eliminated on the interior (9). Certain extrusions were bent to develop smooth corner details. Mechanical connections can also be designed as an integral feature of the ceramic element itself. Figure (10) shows a custom extruded element developed by Spanish architect Francisco Mangado. The design integrates a knuckle-like connector that interlinks the elements into a continuous network. Once supported along the edges, the system can function as a visually complex interior spatial divider.

9 An extruded ceramic cladding system features prominently on the interior of the National Museum of American Jewish History. The warm custom terra cotta tone juxtaposes with the cooler, more technical materiality of the steel glass envelope.

APPLICATIONS: INTERIORS

10 The interlocking stoneware extrusions for this screen prototype evoke knit textiles. The knuckle connector can be easily integrated into the logic of the extrusion process.

Sanitary Ware Glazed porcelain remains widely used in the production of sinks, lavatories, toilet bowls, and similar items. The porcelain clay bodies used are strong, and glaze systems provide a waterproof, relatively scratch-resistant outer surface. Quality features include dimensional accuracy and the material properties of the porcelain. Antimicrobial glazes tend to slow down the growth of bacteria and mold, but never replace proper cleaning protocols. Better sanitary ware has fully glazed surfaces that are easier to clean even in areas hidden from view, while less expensive models can have unglazed areas in zones susceptible to water exposure. Sanitary ware is typically mass-produced using slip casting in plaster or polymer molds. This process clearly favors rounded forms over rectilinear shapes. Sharp corners are virtually impossible to produce, and flatness of larger planar surfaces can be challenging to achieve. The chapter on Products and Technologies shows a recent exception to this convention. Despite automation approaches in the production, manual labor remains a key aspect of manufacturing. Quality checks completed in the factory include bouncing a rubber mallet off the surface to detect hidden cracks. A clear, bell-like sound indicates the absence of cracks to the expert. Custom sanitary ware is uncommon, but not impossible to conceive, especially when it comes to ceramic counters for inset sinks. Such counters can be made from standard flat tile products cut to size and adhered to a rigid substructure. Ceramic counters can even be custom extruded pieces with holes cut in in the factory according to the designer’s specifications (11). 11

NOTES 1

ANSI 137.1 and DIN EN 14411.

2 DIN EN 14411. Many other tolerance measures are also prescribed in this and other norms. A difference is usually made between maximum values and averages. Products with an allowed 2% maximum tolerance in width and length, for example, should not feature an average deviation of more than 1.5%. 3 Applicable codes and standards include ANSI A137.1 and ASTM E 303 (US), and DIN EN 1308 (Europe).

Openings for an inset sink bowl and faucet were CNC-cut into the custom extruded terra cotta countertop.

4 More detail can be found in the technical literature such as Garrison, E. (Ed.). The Graphic Standards Guide to Architectural Finishes. Hoboken: John Wiley & Sons, 2002.

45

CHAPTER 6

APPLICATIONS: EXTERIORS

Ceramic systems for exterior applications deploy the traditional advantages of the material—water resistance, durability, and finish choices—in a context that is less forgiving than many interior applications (1). Outdoor paving, building facades, screens, and roofs are subject to the elements, pollution, and other environmental and human factors. If designed and installed correctly, ceramics can be very durable and robust. However, improper combinations of glaze, clay bodies, adhesives, mortars, or grouts can lead to failures such as water penetration, which are especially problematic in climates with frequent freeze-thaw cycles. Such ceramic systems can quickly deteriorate. The ceramics industry has long recognized these challenges and they are reflected in best-practice recommendations embedded in the various codes and standards. This chapter provides a general overview of the fundamental principles of exterior applications. More information is available both in trade literature and in publications by related industry associations such as the Tile Council of North America, the Tile Association in the UK, the Fachverband Baustoffe und Bauteile für vorgehängte hinterlüftete Fassaden e.V. in Germany, and the respective national groups in other countries. 1 The Elfstedenmonument bridge in the Netherlands is covered with standard flat tiles, adhered to the concrete structure. Artists Bas Lugthart and Maree Blok worked with ceramic manufacturer Royal Tichelaar Makkum to produce a mosaic whereby each tile is an image of a participant in the annual skating race.

Bonded Tile Facades Ceramic claddings form the immediate visual and tactile interface between the building, its surroundings, and the onlooker. They provide weather protection, may control light, sound, views, or modulate humidity and temperature. Ceramic facades can produce a broad range of aesthetics and expressions but from a functional point of view can be divided into barrier walls (with or without external insulation), cavity walls, and pressure-equalized ventilated facades. The classification of exterior applications is determined, in part, by the processes used to attach the element to the substructure, which are typically categorized as adhered (bonded) and mechanically fixed ceramic systems.

2a

2b

2c 2 a/b: Traditional Japanese building with full-body tile facade. The mortar joint is sculpturally expressed by thickening it towards the exterior. 2 c: Complex and colorful ceramic cladding of a traditional pub in Dublin, Ireland.

3 The white precast concrete panels on the facade of the Jaume I High School, in Valencia, Spain, by architect Ramón Esteve studio, are accentuated through brightly colored, tiled courtyards.

By far the oldest applications of ceramic facades are non-loadbearing tiles adhered to a rigid substructure. Earliest examples of this construction type date back to around 600 BC. Terra cotta elements, be they early classic Greek or from the 18 th to 19 th centuries, were essentially bonded to masonry with mortar, occupying a special place within the legacy of bonded tile facades. Today the fear of de-bonding, and the need for breathable outermost facade layers have reduced the interest in this construction type, but many interesting historical examples survive (2). Bonded tile facades remain dominant in many Asian cities—they are not always the most pleasing and interesting, but have proven lasting durability. Both in-situ installation as well as prefabrication on rigid panels—often prefabricated concrete—is possible. In principle, the design opportunities are similar to those for interior tiled walls, always with a focus on matching tile designs and aggregation patterns with the design intention of the building. A myriad of glaze finishes are available that further expand design scope (3). Tile sizes today allow for large panels on the order of 900–1200 mm in length to be adhered, often using cement-based mortars. Smaller tile formats continue to be used as well. Adhered tile facades typically feature grout lines of approximately 5 mm between all tiles that are sealed to prevent water penetration. Expansion joints of 8–10 mm in width need to be constructed such that each tile area measures no more than 12–16 m2. The design of expansion joints should consider any potential dimensional and geometric changes in the substrate the tiles are adhered to, including changes in material and geometry, and the presence of primary structural elements such as columns or slabs. The patterns of tile joints need to be carefully planned, incorporating construction tolerances and the many openings and other geometric features of the facade. Installation drawings, typically created by the architect or the facade contractor, should include this information. For all but very small tiles, metal anchor systems are commonly used in addition to adhesives to secure the tiles. Anchors safeguard against spalling, and usually tie into slots along the edge or back of the tile to remain invisible once the joint is filled with grout (4).

47

4

Stainless steel anchors can be used as additional safeguards for bonded tile facades.

As mentioned, water penetration is always a concern, especially in climates where alternating freeze-thaw conditions could quickly lead to visible and internal damage on tiled surfaces. Barrier walls and cavity walls have slightly different needs and characteristics, but both generally benefit from a dry wall surface. Tiles, especially when glazed, can be specified to resist water infiltration while the grout lines remain a potential weak area. It is unrealistic to assume that workers can produce a complete grout seal over a large surface. Even for impeccable installation, some grouts, especially cement-based ones, can crack over time, thus increasing the risk of water penetration. Adhered tile facades tend to require a certain maintenance effort, which is another reason why they have fallen out of favor in parts of the world. Epoxy grout or silicone/polyurethane sealants tend to be more watertight than cement mortar but require monitoring and occasional repairs. Grouts used for expansion joints are normally silicone-based materials that maintain their flexibility over time. Adhered tiles require a well-finished, flat surface. Masonry and concrete walls are the preferred, traditional base for adhering tiles, and are widely used especially in Europe and Asia. Coefficients of thermal expansion for ceramic and concrete or masonry remain within a similar magnitude to ensure good bonding over time and range from 5 × 10 -5 to 8 × 10 -6. North American steel construction often connects tiles to rigid building boards carried by metal stud wall systems—these are good base surfaces that tend to be flat and dimensionally stable. Use of adhered tiles in combination with timber construction systems is also possible, albeit uncommon. Doing so requires the use of cement-based building boards that are connected to the timber structure, and serve as a basis to which the tiles are bonded. Ceramic tiles can also be bonded to external insulation systems. These are common in Europe and are now more frequently encountered in the USA. The significant weight of multiple layers of plaster, mesh reinforcement, adhesives, and tiles requires rigid stainless steel tie-back systems that can transfer the shearing forces from the outer rigid layer through the porous insulation to the structural wall. Certain sub-surfaces are less suited for adhered tile construction. Steel is generally not recommended because any water penetration will lead to corrosion and expansion—quickly loosening the tiles. Metals such as aluminum heat up quickly and expand or contract three to five times more than ceramic tiles, potentially causing similar problems with delamination, while interior applications on metal surfaces, especially in dry environments, can function well. The majority of bonded tile facades utilize single-layer ceramic elements, but there are hollow extrusions and other elements that can be adhered to sub-surfaces. Extrusions are more commonly used in ventilated facades, but certain benefits may be derived in bonded construction types. The cavity of the ceramic extrusion can be deployed for environmental benefits. Facade tiles developed for a kindergarten in Gandía, Spain, designed by Paredes Pedrosa Arquitectos, illustrates this idea (5). Here the custom-designed and produced hollow extrusions are cemented onto a rigid masonry wall and supplemented by interior thermal insulation. Air is allowed to circulate in the interstitial air space, thus removing heat during the hot summer months and contributing to regulating the interior temperatures. The horizontal joints remain open to facilitate air circulation.

APPLICATIONS: EXTERIORS

5 Extruded hollow elements for architect Angela Paredes’ kindergarten in Gandía, Spain, are split after firing to serve as ventilated facade elements (tubular form) and roof cladding (flat piece). The facade tiles are bonded to a masonry layer that wraps around the steel structure.

5

1 – Ventilated ceramic tile 2 – Brick base 3 – White ceramic tile roof cladding 4 – Concrete structure roof slab 5 – Metal structure 6 – Metal grid

2 1

6

S1

3

4

1

0

2

0,25

1

5

6

0,50 m

6, 7 Ceramic extrusions are mechanically hooked onto an aluminum substructure. Panel subdivisions will remain visible and need to be taken into account in the design of the surface. The blue Muel glaze for the extruded tiles at the Aragonia project in Zaragoza, Spain, is architect Rafael Moneo’s subtle reference to blue ceramic tiles brought to Spain under Arab dominance in the Middle Ages.

49

Ventilated Facades The increasing requirements for thermal insulation of the building envelope have greatly contributed to the development of ventilated facades. These feature an outer rain screen layer that protects a ventilated, pressure-equalized cavity and an insulation layer from direct exposure to sun and rain. Air can freely circulate on both sides of the ceramic cladding elements. They are no longer considered the primary moisture barrier, as is the case for bonded tile facades. Any water that does penetrate beyond the outermost ceramic layer can dry out over time through the ventilated cavity, thus resolving the nagging problems of moisture penetration that have plagued certain historical terra cotta facades. This approach also mechanically disengages the ceramic system from the exterior wall, reducing the risk of cracks caused by movement of the building (6). Ventilated facades are considered the state of the art of ceramic cladding systems. They are available in a wide range of ceramic elements that differ in finish quality, durability, and detailing (7). All systems include the actual cladding elements, a metal substructure, possibly gaskets, and the connectors between the cladding and the other parts of the enclosure (8). 8 Typical pressed tile facade system with aluminum substructure and stainless steel anchors.

Ventilated facades function in slightly different ways under hot and cold climate conditions. In warm conditions, with significant sun exposure, the ceramic elements transfer heat to the cavity, creating an internal stack effect. If designed correctly, air flows in from the lower zones and exits through openings at the top, reducing heat transfer across the cavity through the building envelope and into the interior. Open joints between ceramic elements can further contribute to air circulation. Prototypical buildings such as the Patio 2.12 pavilion (see Chapter 10) have successfully used evaporative cooling on the interior of a ventilated ceramic facade to effectively lower the temperature in the air cavity. This can in turn reduce energy needs for cooling the interior spaces. Ceramics are particularly suitable as cladding for this type of system because the clay body can be designed to absorb and release water effectively for evaporative cooling, and with minimal mechanical ventilation needs. Moisture will not degrade the ceramic elements over time, yet care must be taken to avoid mold growth. Simulation studies have shown energy savings for cooling on the order of 25% in moderate, Southern European climates. In the cold season, the thermal effect of the interstitial air cavity is minimal and can even be detrimental since cold air is directly adjacent to the building insulation. Interesting cases are ventilated facades in moderate climates—such as Southern Europe—where studies show that heat recovery of the warm air in the cavity can lead to a reduction in heating energy of up to 76% compared to a non-ventilated facade (9).1 Additional devices and mechanical systems may be necessary to adequately monitor and control air exchange rates. Such thermal effects can vary for countries with more stringent minimum requirements for envelope insulation.

APPLICATIONS: EXTERIORS

9 Energy Consumption [kWh/m2 ]

Simulation study showing that reducing the airflow in the ventilation cavity can lead to energy savings for the heating season in moderate climates such as those found in Southern Europe.

50

Standard Facade Ventilated Facade (VF) VF + Evaporative Cooling VF + Heat Recovery

25

10

Heating

Cooling Burgos

Heating

Cooling Sevilla

The choice and design of ceramic elements depend on the desired appearance, the available sizes, as well as desirable aggregation patterns. Most common are hollow or single-layer extrusions, but dry-pressed elements are used as well. Hollow extrusions tend to be 20–40 mm thick and can be placed horizontally, which is the most common solution, or vertically. Maximum sizes are in the range of 150–1,000 mm height and lengths of up to 3,000 mm. Unit-weights are approximately 55–65 kg/m2. Single-layer extruded elements of between 14–20 mm thickness are also used, smaller in format and with self-weights starting at around 30–32 kg/m2. Red clay bodies are common, yielding a warm earthen-like color. Stoneware is another common clay body, and both can be glazed to achieve an astonishing range of effects. Typical bending strength is in the range of 13–20 N/mm². The number of profiles available is quite large, and custom profiles can be developed in collaboration with fabricators. Horizontal joints are typically designed to shed rainwater towards the outside. Small vertical butt joints between adjacent ceramic elements remain open, but measure only millimeters and do not permit major water penetration.2 The backs of many ceramic facade elements feature grooves or slots that allow them to hook over aluminum substructures. Facade elements are heavy enough to be held in place merely by their self-weight, and most systems allow for individual elements to be exchanged should local damage occur. This ease of disassembly also potentially facilitates reuse and recycling. A number of companies offer complete facade systems (substructure, gaskets, and ceramic elements) as a kit of parts. Some producers carry standard ceramic extrusions, while others have a standardized substructure with proprietary connection systems, but leave the choice of the extrusion profile up to the designer in close cooperation with the fabricator. Designing a custom extruded facade is practicable except for very small projects where the cost of custom extrusion dies cannot be recuperated through the production volume. In 2013, simple extrusion dies were quoted € 2,000 and up, not including the significant time needed for development and engineering.3 The case study on the Ministry of Urban Development and Environment in Hamburg, Germany, illustrates the process in more detail (see Chapter 11). A typical project will require multiple dies as well as special pieces that may be produced with a combination of extrusion, plastic pressing, or slip casting. Curved elements can be produced by slumping flat extrusions over plaster molds. Corner solutions include tightly bent pieces as well as adhesive bonded mitered corners using epoxy resins. Open corners with accentuating metal or other profiles are also possible (10).

51

10

Closed corner solutions include epoxied joints adhered in the factory, as well as tightly curved pieces post-processed by hand to give a smooth finish.

Dry-pressed, flat tiles are an alternative to extruded profiles. Here the ceramic element is normally thinner, with 7–11 mm, and formats are often larger than those of tiles used in bonded facades. Again aluminum substructures are used, and the tiles are mechanically connected via small slots along the edges or back. In order to hide these connectors, metal clips can be epoxied or sintered onto the ceramic panels, which are then mechanically fastened to the substructure. While extruded ceramic facades have open joints, flat ceramic claddings can feature sealed joints, thus giving a more homogenous impression. Air inlets and outlets are usually located at the bottom and the top perimeter of each facade surface. Special ceramic ventilated facades include large-format tiles similar to those for interior surfaces. Two thin sheets of approximately 3–5 mm can be laminated together using a 0.5 mm fiberglass mesh. The lack of bending stiffness of these slender surface elements necessitates their linear support through aluminum extrusions located on the back to maintain flatness as much as possible. Gentle curves in a single direction can also be achieved with these products.

11 1 2 3 4 5 6 7 8

Special contoured interlayers by CeraVent can provide ventilation for ceramic facades with exterior insulation. 1 – wall 2 – thermal insulation 3 – adhesive layer 4 – wall plug system 5 – proprietary ventilation mat 6 – reinforcement mesh 7 – adhesive 8 – ceramic tile

A special construction approach has been developed for externally insulated facades with an insulation depth of up to 190 mm. Here a deep-textured mat is installed over the external insulation and then coated with multiple layers of plaster, mesh, and adhesive prior to bonding the tiles. The mat allows air to circulate between the insulation and the supporting plaster and mesh layers. The mat, with its adhered tiles, is mechanically anchored through the insulation into a rigid facade layer. The air gap is on the order of 15–20 mm and ensures that moisture can be effectively evacuated from the exterior facade layers (11). Screen Surfaces Logical extensions of the developments in ventilated facades are screens designed to aesthetically enrich envelopes, providing shading and/or privacy by themselves or in conjunction with glass facades. A typical solution is the use of hollow extrusions with common shapes including circular, square (also referred to as “baguettes”), rectangular, or elliptical sections (12). Many special cross-sections, custom-designed and made for specific projects, are equally possible (see Chapter 10 for the Israel Museum case study). Elements can be mounted horizontally or vertically. To complement the bending resistance of the ceramic, aluminum extrusions or steel profiles can be inserted inside the ceramic elements. Horizontal element lengths rarely exceed 1 m, but multiple elements can be mounted on the metal cores to produce overall lengths of 2.5 m or more. Vertical spans can reach a full story height.

APPLICATIONS: EXTERIORS

12 Standard sun-shading lamellas can be combined with other system elements including perforated elements.

Red clay bodies are common for screens, at times colored with pigments or glazed. In exceptional cases technical ceramics have been used, as is the case with the sunscreen elements of the New York Times Building in New York, USA, designed by Renzo Piano Building Workshop. Here the requirements of wind and seismic loads on a high-rise building narrowed the range of options for the screen, and ultimately led the design team to select a ceramic tube normally used as kiln rollers in the production of ceramic water pipes. The pipes consist of aluminum silicates (chemical composition: Al 2O3 60%, SiO2 35%, K 2O 3%) and were glazed to avoid the accumulation of dirt (13). 13 Renzo Piano’s New York Times Building was a first application of ceramic sun-shading elements on a high-rise building. The custom-made elements were produced in Germany from the same material normally used for producing kiln rollers for industrial production of clay-based ceramic elements.

Acoustic Surfaces Special applications for architectural ceramics include acoustic cladding systems for both the interior and exterior. These products are often configured as hollow extrusions—much like those used in ventilated facades—often with earthenware clay bodies (14). The hollow spaces may be filled with mineral wool or other acoustically absorbent materials, but acoustic absorption can be achieved through the perforated ceramic layer itself. Robustness and resistance to moisture are the main advantages of ceramic absorbers compared to many other solutions. Sound enters the hollow interior space of the tiles through slots or holes mechanically cut into the outer layer, where it is absorbed through multiple reflections, ultimately converting it into heat. The tiles usually have grooves on the back that allow them to be mechanically hung onto an aluminum substructure. Some systems deploy single-layer extrusions with slots and holes, and require installation of the acoustic insulators separately onto the rigid surface behind.

53

14

15 Acoustic ceramic surfaces combine the benefit of their selfweight with the intricacy of hollow geometric shapes conducive to converting sound waves into heat.

Different types of roof elements on Antoni Gaudí’s Casa Batlló in Barcelona, Spain. More subtle elements with gentle curvatures combine with highly sculptural configurations produced as slip castings. The broken “Trencadis” tiles are typical for Catalonia and remain in production until the present day.

Roofs Durability and the ability to shed water efficiently is what made ceramics attractive as a roofing solution. Ceramic roof tiles have been used since ancient times and continue to cover roofs across the world, in a broad range of shapes and sizes (15). When installed properly, ceramic tiles have a life span of 75 to 100 years or more, outlasting similar-looking concrete tiles that are typically produced for a 50-year life span. 16

Roof tiles come in a wide variety of shapes, sizes, and colors. The interlocking tile by Ludovici Roof Tile originated in a design that was patented in the 1890s, while the S-shaped tile by Wienerberger GmbH translates the traditional cap and pan systems into a single element. The flat tile by Braas GmbH relies on significant overlaps and slope to resist water penetration. Similar designs are offered by most producers, with a wide variety of sizes and detail features.

Ceramic roof tiles are available in a variety of designs, ranging from simple flat slabs to single-curved, S-shaped, as well as highly contoured and three-dimensionally profiled elements (16). Profiles and channels on the tile underside are designed to prevent water from traveling up the roof (and then inside) when rain combines with wind. Different tile designs work on roofs with different pitches, with a general rule being that flat elements tend to require steeper pitches, while deeper, contoured, and profiled models can provide protection on pitches as low as 15°. Tiles overlap in order to shed water reliably, with the visible portion of the tile referred to as the exposed area. Many tiles are designed to allow for the overlap to adjust by 10–60 mm, thus facilitating subdivisions and placement on roofs of different sizes. Special pieces are designed and made for eaves, edges, roof penetrations, and for meeting other special needs. Traditional roofs, which held up over long periods of time, relied exclusively on the tile for waterproofing. Water that did penetrate simply dried out again—a scenario that today’s well-sealed building envelopes no longer easily permit. In contemporary practice, a separate underlayment provides an added layer of protection. The sheet is supported either by sheathing or battens and the roof joists. This system is effective even with rain and high winds. Roof tiles in areas with freeze-thaw climates need to have relatively low porosity on the order of 3% or less. Local codes and standards tend to classify tiles according to their permitted usage, and designers are wise to adhere to these guidelines. Most roof tiles are full-body tiles available in a range of colors. This includes lighter colors that address issues of urban heat islands by reflecting a large percentage of the incoming solar radiation. Glazed roof tiles are available as well, albeit less common (17). Glazes need to be carefully designed to have thermal expansion coefficients similar to the ceramic base surface. Roof tiles are subject to even more extreme temperature fluctuations than facades, and poor fit of glaze to ceramic base can lead to premature defects. Glazes can produce a smoother surface finish that discourages the growth of fungus and mildew on the roof. Considering the many interesting developments in glaze technology, there seems to be plenty of room for both visually as well as functionally striking ceramic roofing systems that are just waiting to be explored—an example of such an opportunity can be seen in the Santa Caterina Market case study in chapter 9.

APPLICATIONS: EXTERIORS

Most roof tiles today are laid onto battens, simply weighted down by their own selfweight. Protruding features on the underside of the tile just hook over the batten. A few completely flat models are held in place by nails or screws. In areas exposed to extremely high wind loads, additional metal brackets secure tiles in place and avoid uplift with high winds. Traditional tiles such as cap-and-pan systems were laid in a mortar bed, and this practice continues in parts of Southern Europe and beyond. The dead loads can be substantial and require appropriate structural design. Tiles can also be embedded into precast elements configured to work as the outermost roofing layer, thus creating visual contrasts through their reflective glazes in the material context of concrete (18). 17

18 The photographer Barbara Krobath combined glazed tiles into an image on farm buildings in Austria.

Francisco Mangado’s congress building in Zaragoza, Spain, lightens the bold building forms through a playful integration of ceramic tiles into the undulating concrete roof landscape.

Recent needs to produce electricity on site have led to a number of tile products that integrate photovoltaic (PV) elements directly attached to the surface (see chapter on Products and Technologies). While these can be more visually pleasing than the externally attached photovoltaic modules, the dark PV cells lead to higher tile temperatures, risking differential expansion relative to the cooler edge areas. While this is not often critical, it is a concern that designers should address with manufacturers and their warranty claims. Another concern with these integrated systems is the difference in life span between PV cells and the tiles. Unless PV cells can be exchanged easily, the long-term benefits of this more integrated approach may be counterproductive when considering life cycle aspects. Other Outdoor Applications Ceramic elements for landscapes and cityscapes include pavement tiles, wall tiles, outdoor furniture with adhered tile surfaces, as well as elements such as screens, planters, etc. Extruded tubes have been known to be used for outdoor seating areas. Outdoor pools rely extensively on ceramic surfaces to maintain hygienic conditions. Special elements such as gratings and other features can be quite intricate and complex to produce. Many of the issues previously mentioned apply here as well. For exterior ceramic elements the resistance to freeze-thaw cycles and the related water absorption are of prime concern. Good slip resistance for paving systems is crucial. Exterior ceramic elements are occasionally used in harsh climates such as those in parts of North America or Northern Europe, but are more frequently encountered in mild climates without frost in the cold season.

55

NOTES 1 Study conducted in 2012 by the Instituto de Tecnología Cerámica in Castellón, Spain. 2 Many facade systems allow for an elastomeric vertical gasket to be installed directly behind the vertical butt joints as a protection against water penetration. 3 The cost of highly complex dies for the extrusion of large hollow bricks can easily be 20 times larger.

CHAPTER 7

MATERIAL FLOWS: LIFE CYCLE ASPECTS

The construction sector is a major global source of CO2 emissions, energy consumption, and waste production. Building activities consume over 40% of the total primary energy consumption in the USA and in Europe; they contribute approximately 40% to carbon emissions in the USA and 30% in Europe, and generate between 24% in the USA and 34% in Europe of municipal solid waste.1 Current professional practice is narrowly focused on building energy efficiency as the primary goal. This discussion is fundamentally flawed on at least two levels. First, questions of energy consumption and carbon emissions are being almost exclusively focused on the operational phase of the building, thus disregarding upstream production processes and downstream end-of-life scenarios. The embodied energy for a typical office building, for example—the total sum of energy needed to produce and transport materials, make building products, construct, and install all systems—is currently equal to approximately 5 to 8 years of operational energy consumption. As buildings use less energy (and emit less carbon) to maintain comfortable conditions during operation, this balance will shift toward the embodied aspects—even when considering the energy balance over an average 50-year life span. This new reality has led to more material data being included in sustainability rating systems, and to environmental product declarations and similar information for building products becoming more widespread. A second level of confusion is caused by the fact that the basic laws of thermodynamics are routinely overlooked. Broadly, thermodynamics studies energy transfers with a particular focus on heat. From a thermodynamic standpoint, energy cannot be used up within a given system, it is simply converted from one form into another. The goal of building design must be to structure this transformation such that the largest possible portion of transformed energy actually creates value and positive outcomes, for example, heat being used for warming occupants rather than being wasted through envelope heat losses. Energy efficiency ultimately means to maximize useful work for a given energy transformation, thus minimizing entropy. A more mindful use of the term “efficiency” is important because it encourages a holistic view of energy transformations throughout—from material extraction, production, and use to disposal, reuse, or recycling. It shifts our focus from operational energy consumption to a broader life cycle perspective in design. Life cycle design understands buildings as ideally closed-loop systems of energy and matter, built such that the environmental impact from material extraction (cradle) and production (gate) through operation to end-of-life scenarios (grave)2 is minimized. It is related to, yet different from, life cycle analysis (LCA), which is limited

to the analysis itself; being the quantitative system study of energy, emissions, water consumption, and waste involved over the life span of a product, building, or other. LCA is formally governed by ISO 14040, and various databases and kinds of software assist in the assessment. While some level of analysis and quantification of impacts and resources is indispensible for the related life cycle design effort, actually producing a full LCA is extremely cumbersome and, especially for design development purposes, not necessarily useful (1). The LCA also does not model the impact of material mix, connections, and access on the potential to disassemble and reuse or recycle building products. These and other aspects are considered in life cycle design. 1 Clay Extraction Sorting

Grinding

Glaze Raw

Mixing

Materials

Storage + Weathering Water

Producer

Wet Processes

End-Users

Dry Process

Solid Waste Waste Water

Crushing

Ball

Milling

Milling

Grinding

Wet Clay

Liquid Clay

10–20 % Water

30–40 % Water

Plastic Pressing

Waste

Drying Atomization

Dry Clay Powder 2–5 % Water

Slip Casting

Dry Pressing

Ground Tile Recycling

Extrusion

Distributors Drying

Glazing

Glazing Waste Reuse

Drying

Firing

Waste Reuse

Packaging

Life cycle analysis mapping of resource flows during clay extraction and ceramic tile production.

Post-Processing

Cardboard, Plastic Film, Wood Pallets

Life cycle design conceives buildings as temporal material formations, and seeks to source much of the needed construction materials from the salvage or the recycling stream. The actual construction and design strategies should then produce thoughtful configurations of the overall building, its infrastructure, and construction systems such that repurposing, reuse, and recycling of the entire building and its parts is possible. This normally involves limiting the number of materials used (fewer materials means facilitating separation and reuse), designing for the renewal and upgrade of those portions of the building that reach the end of their useful life sooner than others, and ease of separating materials for their own reuse and recycling processes. Informed material selection is an integral aspect of life cycle design. Life cycle analysis and design issues specific to ceramic construction systems include the actual ceramic elements and their support structure. We approach the topic more in relative than absolute terms, because absolute data without context are rarely helpful during the design process. Designers make choices, and other material systems compete with ceramics for interior surface finishes, facades, or roofs,

57

to name a few. We first look at the extraction-to-production phase and its impacts (cradle-to-gate), followed by an analysis of the more complex use phase which, for the purpose of this book, is understood to include the construction process as well. It is here that design aspects are most important. Third, we analyze end-oflife and landfill scenarios (cradle-to-grave) as well as reuse and recycling options (cradle-to-cradle). Finally, we present comparative studies that position ceramics relative to other material systems in the life cycle context. Extraction-to-Production Phase Ceramic production begins with the extraction of raw materials that comprise mostly clay (approximately 60%), but also sand, kaolinite3 as well as other materials. Clay is abundantly present all across the world, but its qualities and properties vary greatly. This has led to regionally typical ceramic products that represent local sources and their related production expertise. Clay is usually harvested by open extraction methods using mechanized equipment such as draglines, power shovels, backhoes, and shale planers (2). Underground mining methods are also used, especially in the USA where higher-quality fire clay is typically found at greater depths, which are uneconomical for open pit mining. Today’s mechanical extraction methods are very efficient—a single worker can extract up to 800 tons of meter-size clay shapes per shift. To help with the necessary breaking down of the material, clay is often stockpiled and weathered for several months. After that period the raw clay is usually processed by crushing, grinding, and screening. The production of dust-pressed tiles also required energy-intensive spray-drying processes. Bleaching and other chemical processes may be necessary to produce particularly pure raw materials. Companies specialized in processing the raw materials into dry mixes are usually located close to the clay pits. For historic reasons this also tends to be the case for the majority of manufacturers. The local nature of extraction and production reduces the cost and impact of transporting the low-value, heavy raw materials. Glaze chemicals are often sourced from more distant suppliers as well, but the amounts used are minor compared to the clay body. 2 Open clay pit in Austria. Pits are usually landscaped once they are no longer commercially used, and much smaller in scale compared to coal mining pits.

Even though clay, sand, kaolinite, and glaze are the primary raw materials needed in ceramic production, the industry relies on other supplies as well. Packing requires cardboard, PE films, and pallets to make sure products arrive in good condition at distribution centers and eventually at their final destination. Within the overall material volume for production these are relatively minor components, with well-established recycling flows for cardboard and pallets. Energy needs for ceramic production include diesel to power extraction equipment and truck transport, electricity to run processing plants, and a combination of electricity and natural gas to run drying machines for clay preparation, power kilns, and production lines. Power for drying equipment and for firing kilns remain the two major elements in the embodied energy and carbon footprint of typical ceramic production.

MATERIAL FLOWS

Most kilns for ceramic tile production today operate with relatively clean-burning natural gas. A study by the Italian Ceramic Center in Bologna, Italy, shows that energy needs for firing ceramic tile have decreased from 10 GJ/t in 1970 to 5–6 GJ/t in 2010,4 a trend in line with process improvements for other materials such as steel. Despite this progress there is plenty of room for improvement, as at present only 5–20% of the kiln energy effectively fires the ceramic products.5 The major portion of the kiln energy input is heat lost through the kiln walls, through the exhausts, and with the tiles that exit the kilns. Heat recovery strategies are being considered to improve the overall process efficiency. Modern ceramic production settings are quite efficient in avoiding waste. Unfired clay waste is fed directly back into the material preparation (3). Water is also recycled. Ongoing research investigates the use of recycled materials as additives to the clay body. Grog—ground-up ceramic—is commonly added to decrease shrinkage and increase porosity. Experiments with other waste materials such as residual sludge from mineral production and water filtration have shown promise but are largely awaiting industrial implementation.6 Ground-up recycled ceramic and recycled glass can also be added to virgin clay (see section on end-of-life scenarios). 3 Unfired tile scrap can be ground up and reused as raw material for production.

Transportation impacts vary depending on the distance between the place of production and the location of use. Different modes of transport have their unique emissions and energy consumption per unit distance traveled. A 2011 study from Spain shows that transportation impacts (emissions and energy footprint) make up 5 – 10% of the total environmental impact of a typical tile produced in Europe, given that approximately half of the production was used nationally, and a quarter each was exported within Europe and to other parts of the world.7 Construction and Use Phase The second major stage in ceramic system life cycles includes construction and use. Actual energy use and emissions during construction are negligible in the overall material life cycle. Solid waste production is small for facades, where ceramic elements tend to be preconfigured in size, thus reducing or even eliminating on-site

59

cutting waste. Adhered interior tile surfaces, however, typically generate more waste as tiles are cut to size based on as-built conditions. On small projects (e.g., a typical residential bathroom remodeling) contractors tend to purchase 10–15% more surface area of tiles to take into account cutting waste, as well as to save extra tiles for future repairs. Resource consumption and emissions during the use phase vary widely. Most facades or roofs may only be subject to the occasional repair but remain without cleaning for decades. Adhered interior tile surfaces, however, are subject to regular cleaning. A typical life cycle analysis of ceramic tiles in the interior 8 shows that much of the environmental impact and embodied energy is concentrated in the manufacturing phase, but the use phase over 50 years actually ranks a close second. These studies include the use of water and chemical products for cleaning (see section on end-oflife scenarios). Considering the significance of the initial production, key factors for understanding life cycle impacts are durability and longevity. When installed correctly, tiles can last an extremely long time. Evidence of this longevity is present in many archeological museums that showcase historic tiles. Tile floor surfaces in buildings today can easily last 75 to 100 years,9 provided substructures are rigid and do not deform over time. Unglazed, full-body tiles can even be refinished by rotary grinding and polishing processes similar to those used for concrete floors. As evidence of the durability of ceramic roof tiles, typical manufacturer’s warranties are over 50 to 75 years. Facade systems are equally durable if detailed and built adequately. Many historic terra cotta facades have lasted 80 or more years. Some have certainly seen their share of cracks and failures over decades of use, and the need to renovate and replace broken elements has kept a small set of producers in business. Degrading physical conditions, however, is but one reason why ceramic systems reach the end of their service life. Changing program needs in buildings, as well as changing tastes and preferences, often lead to the removal of ceramic systems that are technically in perfect condition. For example, in the UK 46% of structures are demolished within 11 to 32 years of age, and the typical life span of Japanese office buildings is less than 30 years for steel frame and almost 40 years for concrete frame buildings.10 A 2004 US study11 of 227 buildings demolished in Minneapolis/St. Paul showed that physical degradation led to demolition only in about a quarter of all cases. End-of-Life Scenarios Ceramic construction systems can be reused, recycled, or landfilled. The decision on what option to pursue depends on many factors, including the ease of removal, the existence of return chains, and the potential to redistribute reclaimed ceramic elements. Other incentives for avoiding waste stem from government regulations or sustainability rating systems that credit recycling and the avoidance of landfill. Prior to utilizing post-consumer ceramics they need to be extracted from the building. Removing the ubiquitous adhered tiles from their substrates is possible but relatively labor-intensive. A certain amount of breakage will occur. Mortar and adhesives then need to be manually removed from the back of the tiles before they are ready to be reused. This kind of salvage work tends to take place primarily when the tiles are historically valuable, or if regulations forbid landfilling of construction debris. Mechanically connected tiles can be more readily reclaimed and reused even when their geometries are intricate (4).

MATERIAL FLOWS

4

5 Architect Arturo Franco reused old roof tiles as interior screens in a warehouse renovation in Madrid. See also the Reclaimed Tile Tectonics case study in Chapter 10.

Tiles can be made from a mix of recycled sanitary ware, glass, and stone dust. Sanitary ware can be easily collected and taken to processing facilities. See also the Recycled Tiles products in the chapter on Products and Technologies.

A small industry has developed that distributes salvaged roof tiles with a focus on historically valuable models. Ceramic facade elements used with mechanical connection systems are relatively recent, so little information is available on realistic end-of-life options. Their removal is quite straightforward, since the commonly used extruded elements are simply hooked over aluminum substructures, held in place by their dead weight. Provided that there is an appropriate infrastructure, their reuse seems entirely possible, although its economic viability is uncertain. Given the increasing tendency of governments to limit or even ban landfilling of construction debris, we will likely see an increase in ceramic reuse. The development of mechanical connections even for interior tile surfaces would certainly help this agenda enormously. At present, only raised floor products can be installed without adhesives, but studies show that mechanically connected interior tile surfaces are feasible (see Chapter 5). Whenever reuse is not feasible, ceramic elements can be recycled through crushing and grinding. The resulting material is usually down-cycled for use as roadfill or landscape construction. The material mix of adhesive/mortar and tile—and possibly brick or concrete from wall construction—does not lend itself easily to reuse in the production of new tiles. Porcelain toilets and sinks, however, are comparatively clean and easy to collect, and a relatively large amount of high-quality glazed ceramic becomes available with comparatively little effort. Niche tile producers have recognized this return stream and are turning the potential waste into newly extruded tiles. Here ground-up sanitary fixtures are mixed with recycled glass as well as virgin material into a new clay body with up to 70% of post-consumer recycling content (5). Clever marketing sells the sustainability of the resulting tile products for a high-end market that now includes large franchises with a desire to shift their image towards the “green” spectrum. Other tiles with recycled content use recycled glass, usually readily available through established glass collection and return streams. The clay bodies can contain up to 50–70% of recycled glass. Sustainability rating systems such as LEED may give credit for products with a certain proportion of recycled content, thereby creating an additional incentive to designers and building owners.

61

A last resort—but still the predominant end-of-life scenario—is landfilling the ceramic demolition debris. The material is chemically inert and will not pollute water or air, but special attention should be paid to landfilling tiles adhered with polymer-based adhesives. Life Cycle Analysis (LCA) and Material Comparisons Ceramic materials form a small portion of the materials used in building construction. The average building contains just over 0.3% (by weight) of adhered ceramic tiles on interior surfaces.12 This proportion increases somewhat when ceramic is used as a facade cladding or roofing system. The relatively small amount of ceramic used in buildings provides the context for the LCA. The relative pros and cons of ceramics compared to other material systems certainly can be evaluated, but it is unlikely that choosing alternative surface finishes, roof or facade systems will have a major impact on the LCA of entire buildings. Adhered tile finishes were subject to an in-depth LCA in 2011.13 Spanish researchers quantified the associated resources and impacts in detail, based on the input of over 50 Spanish tile producers. Given the fact that tile production in developed countries uses extremely similar methods and manufacturing equipment, this study provides good general guidance into the relative impacts during different phases from extraction to end-of-life. The scope of the study includes extraction, processing and production, transport to end-use location, installation using adhesive mortar, a use phase of 50 years, and demolition with landfill 50 km from the demolition site as the typical end-of-life scenario. Transportation assumed that one-quarter of the national production went overseas (5,000 km ship transport), just over one-quarter exported within Europe (2,000 km trucking), while just under half of the production remained in Spain. The use phase included typical cleaning activities with water and cleaning products, on a rhythm between 1 to 14 times weekly, thus reflecting a range of residential to commercial/institutional uses for living areas, kitchens, and bathrooms. The study evaluated the impact of 1 m2 of industrially produced tile (functional unit) with a surface weight of 17–23 kg/m2. Figure (6) summarizes the quantitative results both in absolute terms as well as relative between the different life cycle stages. Global warming potential and primary energy consumption largely result from production, and they are the primary environmental impact of the material system. Further research is needed to reduce the energy needed for drying and preparing the raw materials as well as the energy needed to operate the kilns. Water consumption and ozone depletion potential, on the other hand, relate largely to the use phase and its cleaning activities. They would be similar to other finishes that perform similar

MATERIAL FLOWS

1E + 3 MJ Energy kg Water

Water Consumption

Primary Energy Consumption

Ozone Depletion Potential

Photooxidant Formation

Global Warming Potential

1E-07 kg

Eutrophication Potential

1E-03 kg

Acidification Potential

1E-01 kg

Abiotic Resource Depletion

6 Life cycle analysis of a typical industrially drypressed ceramic tile.

End of Life Use Phase Transportation Manufacturing

NOTES 1 EPA Building Energy Handbook. March 2012, and Eurostat June 2013, http://epp.eurostat.ec.europa.eu/ statistics_explained/index.php/ Waste_statistics, accessed April 2014. 2 The cradle, gate, and grave terminology follows McDonough, W.; Braungart, M.: Cradle to Cradle: Remaking the Way We Make Things. New York: North Point Press, 2002. 3 Rocks containing large amounts of kaolinite along with other minerals are called kaolin. The term is frequently used when describing extraction of raw materials for ceramic production. 4 Giorgio Timellini, Director, Italian Ceramic Center Bologna. Lecture at the Architectural Ceramics in the 21st

Century Conference, MIT, Cambridge, MA , 23 March 2014. 5 Mezquita, A. et. al.: “Energy Optimization in Ceramic Tile Manufacture by Using Thermal Oil”. In: Proceedings 2012 Qualicer. Valencia, 2012. 6 Junkes, J. A.; M. A. Carvalho, A. M. Segadães, D. Hotza: “Ceramic Tile Formulations from Industrial Waste”. Interceram 01/2011. pp. 36–41. 7 Benveniste, G. et al: “Analisis de ciclo de vida y reglas de categoría de producto en la construcción. El caso de las baldosas ceramicas”. Informes de la Construcción, Vol. 63, 522, January–March 2011. pp. 71–81. 8

Benveniste 2011.

9 Jackson, J.: Study of Life Expectancy of Home Components. National Association of Home Builders. February 2007.

10 Yashiro, T.: “Overview of Building Stock Management in Japan”. In: Stock Management for Sustainable Urban Regeneration. Tokyo, Berlin: Springer, 2009. 11 O’Connor et al.: “Survey on actual service lives for North American buildings”. Lecture at the Woodframe Housing Durability and Disaster Issues Conference. Las Vegas, October 2004. 12

Benveniste 2011.

13

Benveniste 2011.

14 Bowyer, J.: Life Cycle Assessment of Flooring Materials. Report Dovetail Partners Inc., 2009. The study compared ceramic tile with 75 % recycled glass, linoleum, vinyl composition tile, composite marble tile, terrazzo, natural cork parquet tile, natural cork floating floor plank,

63

850

Aluminum Honeycomb

Brick

Extruded

1.300

Stone Veneer

MJ

0

12–20 cm glass fiber or foam insulation

Ventilated facades contain more material, have potentially more impact, and a comparative study was conducted by the authors. The study analyzed the embodied energy of a functional facade unit of 1 m2 using extruded ceramic elements (thickness 15–28 mm), aluminum sandwich panels (25 mm deep, with 0.5 mm aluminum facings), brick (115 mm deep), fiber-reinforced concrete (8–13 mm), and granite natural stone (30 mm). This cradle-to-gate study considered extraction to production of all elements including the cladding itself and the typically needed components such as anchors, substructure, and mortar or sealants.16 For metal components, such as aluminum substructures, an average recycling content was assumed. The results are shown in (7). With 850 to 1500 MJ/m2 ceramics require less energy than brick (a direct competitor) or composite panels, but are more energy-intensive than thin concrete panels or granite. While these differences seem significant, they become relatively minor once 12–20 cm of polystyrene or glass fiber insulation is added to the assembly! Overall, ceramics compare favorably with other material systems especially when considering ceramic’s good durability without much maintenance, possibly outliving thin concrete panels.

7

GFRC Panels

functions. How does ceramic fare in an LCA when compared with other materials? A comparative study between eight different flooring materials and ceramic tile with a 75% recycled glass content shows tiles occupying a middle rank in environmental and economic criteria based on a 30-year life cycle.14 Generally, natural materials such as cork, wood, or linoleum rank with lower environmental impacts, whereas certain carpets and marble composite flooring rank poorer than tile. Since tile floors last longer, their impact would likely decrease beyond 30 years. A study comparing ceramic tile with marble showed marble as slightly preferable in terms of environmental impact,15 but in terms of robustness, ease of maintenance, and resistance against water and chemicals tiles would surely be preferable to natural stone. A direct comparison between different LCA studies is difficult at best because product life span and what is and what is not included varies widely. The typically small amount of tiles in a typical building would be unlikely to have any real impact on its life cycle energy footprint and other environmental factors.

Range of typical embodied energy of different facade systems, study by the authors.

nylon broadloom carpet, and wool broadloom carpet. 15 Nicoletti, G. M. et al: “Comparative Life Cycle Assessment of Flooring Materials: Ceramic versus Marble Tiles”. Journal of Cleaner Production 10, 2002. pp. 283 – 296. The study assumes a 20-year life span for tile and 40 years for marble, concluding that marble is approximately twice as environmentally friendly as ceramics. The findings would likely change if the service life of the products was adjusted. 16 The study is based on independently certified environmental product declarations provided by manufacturers. Other data were generated by the authors through an EcoAudit performed with CES Edupack 2013.

CHAPTER 8

SURFACE EFFECTS Cultures have been producing ceramics for thousands of years, and we never tire of their timeless effects, nor have we run out of ways to innovate. The history of ceramic has, in many ways, been a history of surface treatments. Each society and culture has not only expanded the range of glazes, application techniques, and understanding of the complex chemical processes that occur during firing, but has deployed this knowledge in advancing the material culture of ceramics through specific surface designs. This trend continues today. Each year brings new glazes and new treatment processes; periodically, outdated colors and styles return to fashion, and sometimes we find ways to reinvent or readopt traditional methods. More frequently, we are discovering entirely new treatment processes that imbue ceramic surfaces with neverbefore-seen effects or performance capacities. The case studies in this chapter are selected to show a representative spectrum of innovative ways to use a wide range of surface effects, from some of the oldest techniques of bas-relief and colored glazes all the way to the latest nanotechnologies. Among the many common surface effects present in the market today, architectural ceramics are classified as unglazed (sometimes called “terra cotta,” see Chapter 3) or glazed. Between the two, a wide range of surface treatments is possible. In unglazed ceramic one can highlight the materiality of the fired clay body itself. Each clay body, when combined with a specific firing process, reveals the entire palette of earthen to white hues. When a tile is full-bodied (i.e., the clay is consistent through its cross-section), even if weathered or cracked it will always maintain its color. Worn full-body tile floors can be restored to appear almost as new by grinding them. Unglazed tiles need not be plain or homogenous; there are numerous methods for creating designs in ceramics through the use of different colored clay bodies. Encaustic (or inlaid) tiles date as far back as the 13th century, and are produced today through a multi-mold process where each color clay body is cast into the pattern to produce the desired effect. In glazed ceramic, the choices are nearly limitless with every color imaginable as well as patterns, images, metallic effects, mirror effects, and even underglazes that create the illusion of depth. It is not surprising that manufacturers often number their glaze recipes in the thousands or tens of thousands. Glazes will never fade, with ancient Egyptian tiles still holding their luster after nearly 5,000 years. However, the trade-off is that the effect is limited only to a thin surface layer. Color, not surprisingly, is the most commonly utilized surface effect of ceramics. Throughout history these color glazes were applied by hand, giving the pattern or design a painterly quality. Over time, printing methods were developed to consistently produce any pattern imaginable. Modern glazing lines can even incorporate elements of randomization to ensure no two tiles appear repetitive in their surface patterning. Already inkjet technology has been adapted to glaze application. This process starts with a digital image and ultimately leads to highly customizable, photorealistic glaze patterns. A mural of a photograph comprised of hundreds of unique printed glazed tiles, which will never fade, is now possible (1). For both unglazed and glazed ceramics, manipulating the surface to produce texture or sculptural relief has been a key advantage of this plastic material for millennia. Early ceramicists who lacked highly controlled glazes embossed tiles with patterns to ensure the glazes did not bleed into one another. Today surface embossing and glaze choices can work together to heighten the perception of depth or to reflect and refract light. In the Museum der Kulturen Basel, the individual elements are quite formal in their three-dimensionality, yet when aggregated across a field produce a striking, and lively, surface effect (2). In fact, ceramic is so plastic and its aggregation so common that the distinction between surface and form becomes blurred.

1

2

3

Photo mural, inkjet-printed in ceramic glaze in an Amsterdam showroom.

Roof of the Museum der Kulturen Basel, designed by Herzog & de Meuron.

Details of the ceramic elements of the Wallpaper Factory in London, designed by Chassay+Last Architects.

4

5

Benidorm West Beach Promenade, designed by OAB.

Daniel Libeskind’s “Pinnacle” installation in Bologna, treated with a photocatalytic surface.

This spectrum is explored in this chapter’s first case study, the Wallpaper Factory, and in greater detail in Chapter 9, where surface effects expand into broader form manipulations (3). It is important to note that not all surface treatments are driven by aesthetic preferences. Textures in the body can imbue performance qualities like slip resistance, and the choice of body and firing can increase the durability and frost resistance of the ceramic. Likewise, glazes are non-porous and stain-resistant. Ceramics have long been used to clad hygienic or potentially corrosive spaces such as hospitals and laboratories. In Spain, the glazed tiles of Benidorm’s beach promenade (discussed in greater detail in this chapter) were even engineered to withstand the corrosive effects of sand and salt water (4). Advances in ceramic technology are continually improving and widening performance characteristics. While metallic and pearlescent glazes date back to the 12th century, new glazes can now produce a never-before-seen mirror finish. At the nano-scale, advanced titanium dioxide coatings have been successfully applied to create super-hydrophilic photocatalytic surfaces that, with UV radiation from the sun, break down harmful organic pollutants in the air and are, at the same time, self-cleaning (5). In coming years, the inkjet technology used to deposit glaze may be expanded to incorporate metal and polymer deposition, perhaps leading to ceramics with embedded electronics or solar panels. It is not hard to imagine a wide range of performance characteristics that may be engineered for the ceramic elements of the future. The ability of this timeless material to reinvent itself appears limitless.

65

SURFACE RELIEFS THE WALLPAPER FACTORY ISLINGTON, NORTH LONDON, UK

DESIGNER: Chassay+Last COMPLETED: 2009 CERAMIC MANUFACTURER: Shaws of Darwen CERAMIC ELEMENTS: Over 500 825 × 595 × 50 mm slip-cast elements

1 – Elevation of the north facade showing element layout.

Ceramic can be utilized to create a strong connection to the past with methods and techniques that have changed only slightly over centuries. The Wallpaper Factory, a mixed-use development project in Islington, North London, used ceramic to commemorate the site’s industrial past (1, 2, 3). Ceramic manufacturer Shaws of Darwen produced the elements using a traditional casting method that dates back centuries. Fabricator, architect, and facade contractor also worked closely in developing an assembly system for ensuring that the custom pieces would be properly supported. The system is used as a rain screen, with the elements supported on steel angle brackets and pins. Cole & Son was founded in 1873 and is known for historic wallpaper design. Their factory was situated in Islington, an area known at the time for hand-block printing

SURFACE EFFECTS

companies. To note this history, architects Chassay+Last procured two of the original wood blocks used for hand printing the paper. They worked with Shaws of Darwen, a company founded not long after Cole & Son in 1897 as the Shaws Glazed Brick Company. Over time, their production has evolved and Shaws of Darwen is currently divided between sanitary ware, such as their signature Belfast sink, and architectural terra cotta and faience. The architectural side is further divided between new builds and architectural restoration—in some cases for facades fabricated by that same company over their nearly 120 years of activity. In the last two decades, manufacturers like Shaws of Darwen have noticed a resurgence of interest in using ceramic on facades and in the last ten years an interest in custom-made ceramics. For the Wall-

paper Factory traditional hand-craft was combined with modern firing techniques. Using the shape of the printing wood block as a guide, a model of the wallpaper design was hand-carved in clay as a relief (4, 5). This was then used to produce plaster molds from which the final pieces were slip-cast (6, 7, 8, 9). Slip casting is generally considered to have been invented in England sometime between 1730 and 1750 and became an important industrial process during the subsequent Industrial Revolution. The section of the facade consists of over 500 identical 825 × 595 mm tiles with a thickness of 50 mm. The pieces were fired with a more fluid glaze, which would run off the high points and pool in the low points, creating a two-tone effect that accentuates the bas-relief of the surface. This intentionally varied glaze also emphasizes the craft nature of the ceramic production.

2 – North facade and building front.

3 – Street level view of the north facade.

4 – The bas-relief pattern is based on a historic wood block used for printing wallpaper.

5 – Detail of the bas-relief pattern and glazing, which accentuates the edges.

6 – The clay is cast into the plaster molds.

8 – Elements were laid out prior to delivery to ensure proper fit.

7 – Application of the custom glaze.

9 – The final assembly system was developed collaboratively by the architect and manufacturer.

67

COLOR VARIATION

DESIGNER: Sauerbruch Hutton COMPLETED: 2009 CERAMIC MANUFACTURER: NBK Architectural

MUSEUM BRANDHORST MUNICH, GERMANY

Terracotta CERAMIC ELEMENTS: 36,000 40 × 40 × 1,100 mm extruded ceramic rods in 23 colors

1 – Detail of the colored rods and folded metal.

While individual colors may come in and out of style, the use of color as a salient feature in architecture is timeless. By the mid-20th century any color was possible in ceramic glazes, and modern production processes enabled absolute color accuracy and consistency across large quantities. The work of architects Sauerbruch Hutton, with several of their projects featuring glazed ceramic elements, explores how we perceive color. The 12,100 m2 large Museum Brandhorst, built at a cost of € 46 million and completed in 2009, was designed to house an extensive private collection of late-20th century and contemporary art and sits on the edge of Munich’s museum district. The building consists of three simple interlocking volumes, providing a quiet backdrop to the building’s stunning polychromatic facade, comprised of 36,000 ceramic rods glazed in 23 different colors.

SURFACE EFFECTS

From a distance the facade appears homogenous and flat, but up close the intensely colored (40 × 40 × 1,100 mm) rods become distinct (1, 2, 5). These vertical rods are offset 42 mm from a perforated, horizontally folded metal skin of alternating colors. The depth and layered color of the system adds dynamism to the facade, casting shadows and changing appearance according to the observer’s position and movement. The rods are hollow, square-profile extrusions produced in a medium-volume industrial process by custom ceramic manufacturer NBK. For the assembly, each rod is supported by two bolts embedded in the ceramic, which connect back to a metal substructure, passing through pre-drilled holes in the perforated metal skin. A nut, attached by hand, secures the connection. The perforated metal skin is supported on a perpendicular substructure and backed

with insulation for the added benefit of dampening street noise. Each volume of the museum has a distinct color scheme (3). While they may appear from afar to be single neutral colors, they are in fact comprised of three families of eight colors with unique variations of lightness and hue. In addition, the placement of each colored rod was not random but painstakingly follows a precise pattern established by the architect. To ensure that the glazing matched the desired color, Sauerbruch Hutton relied on the manufacturer’s experience (4). Though the product of a highly precise industrial process, the facade does retain an element of craft associated with the ceramic material. This combination of volume production, color, and craft lead many to consider the ceramic an appropriate reflection of the contemporary art housed within.

3 – Each volume has a different color scheme.

2 – As one approaches from the street the colors become distinguishable.

4 – A mock-up was installed to test the color schemes and visual effect.

5 – From a distance the perception of individual colors is difficult.

69

CUSTOM GLAZES THE HOLBURNE MUSEUM EXTENSION BATH, SOMERSET, UK

DESIGNER: Eric Parry Architects COMPLETED: 2011 CERAMIC MANUFACTURER: Shaws of Darwen CERAMIC ELEMENTS: More than six unique element types ranging to 1 m in length and 55 mm in thickness

1 – Sydney Gardens elevation.

2 – Second floor plan.

The limitless variety of available glazes means that any ceramic project has the potential to customize its surface treatment to its specific context. Architects work hand in hand with ceramic manufacturers to determine color, create illusions of depth, and vary glaze thickness to create highlights and shadows. In this way the surface effect works to enhance the formal characteristics of the ceramic. The Holburne Museum terminates a 600 m long vista down Great Pulteney Street among the classical Georgian architecture of historic Bath. The art museum is a Grade I listed Unesco World Heritage Site, and sits at the entrance to the remains of the country’s last 18 th century pleasure garden. In 2002, Eric Parry Architects of London won a competition for the renovation and extension of the museum. Given the sensitivity of both the building and its historic site, a long debate followed with final approval of the design given in 2008, which included a glimmering green ceramic and glass facade (1, 2, 3) . To achieve what is described as the “arboreal lyricism” of the facade, the archi-

SURFACE EFFECTS

tect sought to eliminate any perception of a grid. Ceramic fins cover all vertical seams as well as the attachment mechanisms (4, 5). While the facade may appear to be merely flat panels and vertical fins, it is in fact comprised of dozens of unique forms including three unique panel sizes, corner conditions, fins, and caps (6). The large pieces, ranging up to 1 m in length, were produced by Lancashirebased Shaws of Darwen, who have a history of working with Eric Parry Architects on custom projects. The units were therefore produced in the same manner as the manufacturer’s fire clay sinks, through an industrial form of slip casting that uses a thick slurry of clay. This allowed for greater complexity with interlocking forms. With wall thicknesses averaging 50 mm, the units are also significantly thicker than common extrusions with wall thicknesses between 8 and 11 mm (7). The design of the units, and the manner of their attachment, was influenced by the significant shrinkage and deformation that occurs in ceramic pieces of this size. By using slip casting, the overall shrinkage

is reduced to around 4.6%. Still, all units were dry-laid out to ensure that tolerances were met before the units were sent to the site. Nevertheless, a greater degree of wastage was estimated by the architects compared to more conventional systems. Of particular importance was the custom glaze developed for the project to create ambiguity of depth and color in the surface. The underlayer of glaze is darker, the overlayer contains titanium to give it lightness, and the two layers are fired together. Beside the green ceramic, the glass curtain wall reflects the greenery of the gardens with similar illusions of depth. As ceramic glazes are a form of glass, the architect utilized the material qualities of pairing glass and ceramic, each with their own color, transparency, and reflectivity. Ultimately, the extension’s custom facade conveys a sense of craft—appropriate for the art within—that would have been lacking in a conventional system.

3 – View from Sydney Gardens.

4 – Detail of Sydney Gardens facade.

6, 7 – Manufacturing process of bespoke ceramic cladding at Shaws of Darwen.

5 – Exploded perspectival section showing ceramica element attachment.

71

THREE-DIMENSIONAL SURFACES

While forms of metallic glazes date back to the 12th century, mirror glazes were developed much more recently and offer new opportunities in ceramic finishes. Dating back to the middle of the 19th century, the Museum der Kulturen Basel sits in the heart of the medieval city’s Cathedral Hill. When faced with the task of extending the neoclassical building to accommodate a larger fraction of the museum’s more than 300,000 objects, Herzog & de Meuron chose to grow vertically rather than filling in the historic courtyard (1). An attic space was designed with a folded roof that reinterprets the medieval rooflines of the city in a modern way (2, 3). Most striking are the custom-made ceramic elements, covering an area of approximately 1,300 m2 (4, 5). The three-dimensional hexagonal ceramic elements are an abstraction of the

SURFACE EFFECTS

COMPLETED: 2010 CERAMIC SUPPLIER: Agrob Buchtal GmbH CERAMIC ELEMENTS: 1,300 m2 of four types of slip-cast hexagonal units with 196 mm edge lengths and 12 mm wall thickness

MUSEUM DER KULTUREN BASEL SWITZERLAND

1 – Section showing the new roof and gallery space.

ARCHITECTS: Herzog & de Meuron

2 – Complex geometry of the structural form.

tiled roofscape of Basel. However, unlike the orange-red terra cotta of its neighbors, the greenish mirrored glaze of the museum specifically references the traditional green roof tiles of the landmark cathedral that dominates the local skyline. While the cathedral roof garners attention through its diamond patterns of white, red, yellow, and green, the Museum der Kulturen gives a dynamic quality through its pattern of convex, flat, and concave ceramic elements that vary dependent on the viewer, incidence of light, and weather. The overall effect is a design that seems fitted to its surroundings and yet still stands out as a signature work of architecture. The ceramic elements were customdesigned by the architects and fabricated by ceramic specialists Agrob Buchtal. The striking mirrored glaze was also cus-

tom-developed, going through a trial of recipes until the exact desired characteristics were met. This is a common process for Agrob Buchtal, which has developed over 15,000 custom glaze recipes over the past decades. The tiles were produced using a modified industrial slip casting process with plaster molds in order to achieve the necessary precision. The formwork included three hexagonal elements (convex, concave, and flat) as well as a trapezoidal end piece with edge lengths of 196 mm and a wall thickness of 12 mm (7, 8). The mounting system allows each individual element to be removed independently in order to access the water barrier (6).

3 – The museum set among the terra cotta roofscape of Basel.

4 – Assembly pattern and element sections.

6 – The elements are individually installed on the mounting system.

7 – Detail of the mirror finish with its deep green underglaze.

5 – View of the addition from the courtyard.

8 – The angles and forms of the elements paired with the mirror glaze scatter the light.

73

PEARLESCENT GLAZES

DESIGNER: COR asociados, Miguel Rodenas + Jesús Olivares COMPLETED: 2011 CERAMIC MANUFACTURER: COR asociados CERAMIC ELEMENTS: 498 × 498 × 19 mm, 685 m2

ALGUEÑA MUCA MUSIC HALL AND AUDITORIUM ALICANTE, SPAIN

1 – First-floor plan.

Pearlescent glazes date back to the 12th century, became renowned in the green pearlescent glazes of Hungarian manufacturer Zsolnay, and were used frequently by the Art Nouveau movement. They then fell out of style. In Algueña, architects COR asociados, Miguel Rodenas and Jesús Olivares, revived and modified a glazing technique that once might have adorned elements of their grandparents’ homes, seeking to create something new. Algueña is a small town of 2,000 inhabitants with an economy of agriculture and marble industries. The white hills of the quarries are a prominent backdrop in the town landscape. COR asociados were asked to design a flexible space that would incorporate the music activities of the town and be a landmark for the community—this on a limited budget of about € 560,000. The project included the renovation of an abandoned guardhouse from the 1960s and the construction of a new 230-seat, 350 m2 auditorium (1, 2). The focus of the project is

SURFACE EFFECTS

2 – Massing model showing the new pearlescent concert hall and existing renovated structure.

a mother-of-pearl facade that both stands apart from, and yet resonates with, its surroundings. For the landmark component, rather than attempt monumentality on a limited budget, the design pursued an approach based on the psychology of perception. The goal was a blurring effect with vibrant elements constantly changing according to the viewer and lighting (3, 4, 5). The architects initially pursued all materials that might produce these effects, including glass, metals, and plastics, but ultimately settled on ceramic for allowing significant customization on budget. Research was conducted over a period of eight months to refine the glazing process and create the desired brightness, durability, and color. The architects worked with a small ceramic manufacturer with expert knowledge about ceramics and the ability to customize the glazing process while keeping costs down. A standard frost-resistant exterior porcelain was chosen to allow the research

to focus exclusively on the iridescent glaze that involves a traditional triple-fired process. The tiles are dry-pressed using conventional processes and bisque-fired at 950°C. The white enamel base is then applied and fired at 1,180°C to vitrify the pieces. Finally, a thin metallic coating is deposited on the surface and fired at 780°C (6, 7). The tiles were then adhered directly to the concrete structure (8, 9). The mother-of-pearl effect is not entirely new, being a chemical process traditionally used in Spain to coat ceramic window sills. These traditional pieces of a green color base fell out of production over time due to complications with the process causing breakage. COR asociados, working with the ceramic manufacturer, revived the process. They changed the color base to white, resolved the production problems, and enhanced the pearlescent effect to create something contemporary. The firm now markets and sells custom versions of these tiles for use on other projects.

3 – The addition and renovation creates a clear separation from the historic structure.

75

4 – Aggregated across the facade, the tiles both scatter light and reflect the sky.

5 – West facade.

SURFACE EFFECTS

6, 7 – Application of the thin metallic coating between firings.

8, 9 – Adhering the tiles to the structure.

77

GLAZE TRANSFERS

DESIGNER: Eric Parry Architects COMPLETED: 2014 CERAMIC MANUFACTURER: Shaws of Darwen CERAMIC ELEMENTS: 25 m long slip-cast cornice in 39 sections with 30 unique designs

ONE EAGLE PLACE LONDON, UK

1 – Piccadilly elevation.

The ceramic industry continually adopts technologies utilized by other industries, particularly printing. Screen printing, developed in China during the Song Dynasty (AD 960–1279) and introduced to Europe in the 18th century, was soon adopted by the ceramic industry for applying glazes to ceramic, which previously was done exclusively by hand. Now widespread in certain sectors of the ceramic industry, these processes offer designers opportunities for architectural applications. One Eagle Place bridges the historic Piccadilly boulevard it fronts, and the neon lights (now LEDs) of Piccadilly Circus just meters away. Functionally, as the building faces north, the glazed facade is meant to pick up the natural—and artificial—light. The building adopts the grid and structure of its classicist neighbors and also the dental friezes, cornices, and rustication,

SURFACE EFFECTS

2 – Piccadilly facade details.

but offers a contemporary interpretation of ornament in architecture (1). The facade is entirely clad in custom off-white ceramic elements. They are mortared to create a continuous sealed surface, acting more as a brick wall than a rain screen (2, 3, 4). Of particular interest is the 25 m long, brightly colored cornice designed in collaboration with artist Richard Deacon (5). The cornice is divided into 39 multi-faceted sections of 14 different types, with each facet glazed in one of 30 designs. Each of the 39 cornice sections is comprised of two or three discrete ceramic elements that only join on internal facets so as to minimize the visual presence of the joints. While seemingly small from a street-level view, some of the ceramic elements weigh up to 200 kg (6)! The design of the glazed elements was implemented by means of a glaze transfer,

a form of decal. First, in a process similar to silk screening, glazes are printed onto a substrate sheet. They are then wetted and applied to a fired ceramic element and eventually fired again. This glaze transfer is a common method for repetitively creating precise glaze designs. Glaze transfers, or decals, are widespread in the ceramic industry, being used for almost every decorated plate, bowl, coffee mug, or kitsch souvenir, and dating back to the middle of the 18th century. However, they are not commonly used in architectural applications. The manufacturers spent months working closely with the artist to ensure the transfer colors were exactly right according to the design (7). The result is the polychromy of One Eagle Place, which, Parry notes, “has a smile”.

3 – View of the Piccadilly facade.

4 – Piccadilly facade cutaway.

6 – Richard Deacon cornice. Ceramic blocks in dry lay.

5 – Piccadilly facade, featuring a ceramic cornice by Richard Deacon.

7 – Numerous samples were created to ensure color accuracy.

79

HIGH PERFORMANCE SURFACES

COMPLETED: 2009 CERAMIC MANUFACTURER: Keramia Ceramicas CERAMIC ELEMENTS: 1,500 m promenade paved mm triangular tiles in 22 colors

1 – Geometry of the tile pattern in plan and section.

SURFACE EFFECTS

and Xavier Martí Galí

in extruded 430 × 15 mm circular, and 120 × 15

WEST BEACH PROMENADE BENIDORM, SPAIN

Benidorm West Beach Promenade is a highly praised achievement of the 500,000- person high-rise resort town. An undulating form of white concrete snaking 1.5 km along the beach with a maximum width of 30 m, the promenade provides protection from the sea, it enables rainwater capture, views to the sea, access to underground parking, access to streets, and offers a range of activity spaces. The design ties together culture, local materials, and the intellectual concepts of designers OAB (Office of Architecture in Barcelona). In addition to the complex geometry cast in white concrete, the signature design element of the project is the colorful ceramic pavers fired in 22 different colors that gradually shift and interlace along the promenade. Dozens of models, from paper and poster-board to 4.2 m long maquettes weighing 250 kg, were created over a period of six years to refine and understand the complex geometry (1, 2). In order to achieve

DESIGNER: OAB, Carlos Ferrater

the flexibility needed for covering the complex surface of the promenade, a ceramic paver was designed exclusively for the project. The circular geometry is directionless, allowing for the seamless integration with the curvilinear promenade as well as the mixing of different braids of color. The weaving pattern also separates and at the same time integrates the changing levels of the project (3, 4, 5, 6). In order to address the difficult environmental challenges of the site—high traffic, slip resistance of wet tiles, corrosive salt, and abrasive sand—OAB involved the Instituto de Tecnología Cerámica (ITC), a research organization established to support the Spanish ceramic industry cluster. Using European and Spanish methodologies, ITC was able to determine the mechanical resistance (break load), slip resistance when wet, and permanence of this characteristic over time, also taking into consideration the abrasion of sand and

2 – Photograph of a design maquette.

water, of a variety of products available on the market. Manufacturer Keramia Ceramicas was able to produce pieces in 22 different colors to meet the requirements. The circular units are 430 mm in diameter and 15 mm thick, with triangular infill units with a width of 120 mm. The units were extruded and cut with custom dies. The body of the tiles is a special mix that after firing forms a mass with almost no porosity and high mechanical resistance. To create a slipand stain-resistant surface, the glazes incorporated alumina, a tough aluminum oxide that resists the wear of the sand. Multiple layers of glaze enamel were applied in order to ensure vivid and lasting colors. Finally, the firing curve was modified to 50% longer at higher temperatures, to ensure the vitrification of the body and integration of the layers of enamel with each other and the body. 1 Ferrater und Galí 2011.

3 – Benidorm promenade, looking west.

5 – The tiling pattern weaves through different paths.

4 – Benidorm promenade, looking east.

6 – Detail of the tiling pattern with circular and triangular units.

81

INKJET PRINTING

1 – The Cretaprint is one system for applying glaze using inkjet technology.

While applying glazes by hand still exists for specialty artisanal products, the glazing processes adopted by the industry are largely the same as conventional printing of paper or textiles. Glazing systems are installed such that glazes are applied directly onto tiles on the production line. In typical high-volume production settings, any variations or individual glazes are extremely difficult to implement unless large numbers of tiles are required. Individual glazes are most often achieved by oscillating the application systems or alternating within a set number of patterns, which requires physical, mechanical changes of the glazing machines. Given the similarities between industrial glazing and paper printing, it is not surprising that over the past 15 years inkjet printing technology has been adapted for decorating ceramic tiles. The result allows digital image replication with bespoke patterns that are as easily replicable as mass-produced designs. The technology permits the development of large photorealistic murals with all the inherent benefits of ceramic tiles, such as durability, easy maintenance, and lasting color. In the Pamplona restaurant La Mandarra de La Ramos (4), the festival of San Fermin—popular for

SURFACE EFFECTS

its running of the bulls—is commemorated in ceramic floor murals produced using inkjet printing technology (1, 2, 3). Since the images are baked into the glaze, and not applied on top of the tile, they are capable of withstanding the heavy foot traffic and daily abrasive cleanings of a restaurant floor (5, 6, 7, 8). Similarly manufacturer Ceracasa Ceramica has worked with the brewing company Mahou-San Miguel Group to produce exterior advertisement murals that will never fade or deteriorate. Styled after classic advertisements, these murals offer an interesting alternative to the fading, but now highly appreciated, advertisements painted on side walls of buildings in the early 19 th century (9, 10). Aside from specialty products, the technology can also be used in the large market for tiles that mimic natural materials such as stone and wood. Currently, glazing systems struggle to mimic the complex variations that make each piece of wood or stone unique. Unlike the single printhead system of multi-pass printers seen in homes and small offices, industrial inkjet printers use a single pass with multiple printheads in order to apply the glaze in-line. Here, each color has a print bar consisting of at least ten printheads mounted above the tile

2, 3 – The system uses multiple print heads to apply the glaze quickly.

transport system, operating at speeds of approximately 0.5 to 1 m/s. This allows the inkjet printers to keep up with the speed of modern ceramic tile manufacturing lines. The development of ceramic inkjet printing has largely mirrored conventional inkjet technology. Future developments will likely see improved color quality and increased resolution. To improve competitiveness with conventional glazing systems, single-pass printing speeds may increase, but significant challenges would have to be addressed in the inks and data transfer for this purpose. The most promising developments will likely involve depositing a wider range of materials such as ceramics, metals, and polymers.1 Printing ceramic slip could produce colors based on the clay body rather than pigments in glazes. Metals and polymers could add novel functionality to ceramic products. For example, as a market for the printed circuits, industry ceramics could incorporate sensors, switches, and acoustic transducers. In the coming years, ceramic tiles may also act as solar panels, occupancy sensors, speakers, display screens, and more.

1 Hutchings, 2010.

4 – La Mandarra de La Ramos restaurant in Pamplona, Spain.

5 – Detail of printing resolution.

6 – The bar features cityscapes, while the floor is an aerial view of the famous running of the bulls.

8 – Each tile is unique and installed in its proper place in the mural.

7 – The process is the same as in traditional tiles and withstands foot traffic and wear equally well.

9 – Printed murals enliven an otherwise blank building wall.

10 – The cost is significantly less than that of hand-painted murals and the result is more durable.

83

NANOCOATINGS

DESIGNER: Studio Daniel Libeskind Architect COMPLETED: 2013 CERAMIC MANUFACTURER: Casalgrande Padana S.p.A. CERAMIC ELEMENTS: 120 pressed stoneware panels 600 × 1,200 mm

PINNACLE BOLOGNA, ITALY

1 – Section illustrating the concealed steel substructure.

There is a vast potential for new nanotechnology treatments on ceramic. In the 1960s scientists discovered the photocatalytic properties of titanium dioxide (TiO2), which off-gasses when exposed to water and UV light. This oxidizing effect destroys virtually all organic compounds. Water, forming a low contact angle when hitting superhydrophilic surfaces, spreads, maximizes contact, and washes off cleanly. The combination of sunlight and rainwater results in a self-cleaning surface. For the 2013 Bologna Water Design conference, which looked at water in the urban context, architect Daniel Libeskind

SURFACE EFFECTS

and ceramic manufacturer Casalgrande Padana collaborated to create the installation Pinnacle, which featured Casalgrande Padana’s Bios Self-Cleaning technology (2, 3, 4, 5). In a reversal of the traditional relationship of manufacturers designing products for architects, the structure is clad in panels designed by Libeskind as a product line for Casalgrande Padana. The panels feature a subtle bas-relief geometric pattern that, combined with a special metallic stainless steel glaze, reflects and scatters light. The architect found inspiration from numerous references such as light, water, sky, the horizon,

and desire. The installation is set in the 17th century surroundings of the Cortile del Priore dell’ex Maternità. Pinnacle is comprised of 120 stoneware panels of 600 × 1,200 mm and fired at 1,235°C. The tiles are supported by concealed fixings over a steel substructure and primary structure (1). The metallic effect is achieved by saturating the glaze with metal oxides, improving the crystallization process during firing, and then polishing the metal particles embedded in the glaze after firing. Subsequent to this process, the company’s patented Bios Self-Cleaning treatment was applied.

3 – The ceramic achieves a metallic effect through metal oxides in the glaze.

2 – The ceramic elements, designed by Daniel Libeskind, feature a subtle bas-relief.

4 – The installation is set in the Cortile del Priore dell’ex Maternità.

5 – The ceramic elements are treated with a photocatalytic nanocoating.

85

CHAPTER 9

PATTERNS AND AGGREGATIONS

1 – View of the Caterina Market roof in Barcelona.

2 – The ceramic facade of the Muhammad Ali Center in Louisville, Kentucky.

In recent years contemporary architecture has reexamined the nature of ornament, while at the same time finding new ways to clad the complex surfaces and structures brought on by the digital age. “Pattern,” once thought of as merely an aesthetic indulgence, has recaptured the interest of designers when generated through complex multi-variable algorithms. At the same time mosaics, often identified as historic, still exist and are even catalyzed by robotics and other technologies that make them technically and economically feasible to produce and install. They continue to maintain their relevance to the vast scale of architecture and cities today, and reestablish deep cultural connections albeit in highly contemporary ways. Architects are also exploring the new robustness and improved strength of ceramic tiles, once thought too thin and brittle to exist except where fully adhered to rigid substrates. Tiles today can be self-supporting or even structural, and the recent potential to explore the depth dimension invigorates the age-old opportunities inherent in the rich patterning of tiles. The cases in this chapter are divided into three parts. The first showcases several examples of novel, architect-designed, and complex geometric tiling patterns. We then look at how mosaics have been reinvented through 21st century digital technology. We conclude with how architects are pioneering three-dimensional aggregations, and thus expand the traditional view of tiled surfaces as two-dimensional patterns into a bold third dimension. Organic curving forms are not entirely new to architecture, and historically ceramic has played an important role in cladding complexly shaped surfaces. Here the use of small-format tiles adhered to an underlying complex surface make for a cost-effective, versatile finish. The verb to “tessellate” in modern usage simply refers to tiling a surface. It takes its root from the Latin tessera—small stone cubes used in mosaics—emphasizing that at its core tessellating is an act of design. Perhaps the best ceramic tile examples come from the Golden Age of Islam where complex geometrical patterns were incorporated as surface decoration, both two- and threedimensionally, tessellating the complex curvatures of onion domes and corbelled mihrabs (see Chapter 2). Today, as architects and designers increasingly adopt new tools and training such as scripting, programming, and parametric modeling, a new interest in complex tessellations has emerged.

3 – The CCCloud by Kengo Kuma and Associates uses ceramic elements structurally.

4 – A 2015 installation by Martin Bechthold and researchers at the Harvard Graduate School of Design uses large format tiles in a 3.6 m structural assembly.

The earliest mosaics were pebbles, but over the centuries they have become identified as much with ceramic as with stone. Ceramic tiles with their myriad of colors were a natural choice to create vivid mosaics. Yet the cost of labor has driven these works of art to become increasingly rare. By the 19 th century manufacturers were imprinting larger tiles with patterns to make them appear like smaller mosaic tiles. Yet today mosaics do not need to be comprised of small units. The scale of today’s buildings paired with digital technology means urban-scale mosaics can be created where an entire panel—or dozens of tiles as we will see in the Santa Caterina Market—takes the place of a single pixel (1). In the Muhammad Ali Center in Louisville, Kentucky, USA, the facade-scale image created by colored ceramic elements and clearly visible from far away dissolves into seemingly random squares of color as one approaches (2). While the word “tile” today may refer to a thin slab of some material, its root is the Latin tegula, specifically a fired ceramic roof tile. It implies a unit that is aggregated—not necessarily in a flat plane—over a surface. Far from digital, these ceramic roof tiles with the flexibility of their aggregation have clad curved roof structures in East Asia for centuries. Today, architects are finding new ways to aggregate tiles over complex surfaces and are even experimenting with pulling ceramic tiles off their substrates to be truly three-dimensional (3). Large-format ceramic (4) with lengths of over 3 m and a thickness of 3–5 mm can even bend without breaking, a structural property heretofore unheard of in ceramic (see Chapter 5). This chapter is but a cross-section of the contemporary range of explorations in tessellating and aggregating ceramic elements. Traditional methods of mosaic are being re-imagined and realized at new scales. Robotic technologies are making mosaics not only economically feasible again, but more importantly they provide a crucial linkage between a historic art form and the digital age. The chapter then explores how new manufacturing techniques and controls are producing tiles strong enough, and reliable enough, to be freed from their sub-surface. These three-dimensional aggregations of ceramic elements represent a new field of exploration for architects and designers.

87

COMPLEX GEOMETRY PULSATE PRIMROSE HILL, LONDON, UK

DESIGNER: Lily Jencks and Nathanael Dorent COMPLETED: 2013 CERAMIC MANUFACTURER: Marazzi Group STRUCTURAL DESIGN: Manja van de Worp, NOUS Engineering, London CERAMIC ELEMENTS: 2,950 100 × 600 × 5 mm pressed stoneware elements

1 – Plan and section of the changing floor and ceiling heights.

2 – Capitol Designer Studio facade.

Modern theories of computation in architecture have brought tessellating surfaces through complex algorithms to the forefront of architectural discourse and made them the subject of serious academic study. Like mosaic, this complex tiling is also often considered labor-intensive and therefore prohibitively expensive. Pulsate demonstrates that geometric tiling can be both complex and feasible. Pulsate is a pop-up installation designed for tile distributors Capitol Designer Studio (CDS) in Primrose Hill, London. The interior project challenges traditional perceptions of ceramic tiles as merely floor or wall coverings by creating a complex

PATTERNS AND AGGREGATIONS

pattern that blends floor, wall, ceiling, and furniture into a single surface (1, 2). Designers Lily Jencks and Nathanael Dorent were inspired by Op Art and Gestalt psychology, intending the installation to question the perception of distance and shape (3, 4, 5). The designers chose the Sistem N tile line by Italian manufacturer Marazzi— literally off the shelf from the distributor. The tiles are fine porcelain stoneware, 100 × 600 × 5 mm, dry-pressed, and fired at over 1200°C. The slip and impact resistance of the tiles makes them suitable for both floor and wall applications. A palette of four standard colors was used to create

the undulating wave effect of the pattern. The design highlights the geometric complexity of continuous tiling patterns as the herringbone floor pattern extends up the walls and reconnects with itself on the ceiling. In addition, to ensure the continuity of the pattern, the floor had to be sloped at the same degree off-normal as the walls. This meant that even a couple millimeters deviation in the wooden support structure would cause the pattern to fail. The tiles were adhered to the wooden substructure using traditional methods, but a high degree of precision was required from experienced installers marking off the pattern (6).

3 – The pattern works with the forced perspective of the space to challenge the viewer’s perception of distance.

4 – A view in the opposite direction reveals the forced perspective.

5 – Complex geometry ensures the continuity of the pattern across the changing surfaces.

6 – The visual effect depends on the precision of the tile placement.

89

COMPLEX ASSEMBLY

DESIGNER: Manuel Herz Architects COMPLETED: 2010 CERAMIC MANUFACTURER: NBK

JEWISH COMMUNITY CENTER MAINZ, GERMANY

Architectural Terracotta CERAMIC CONSULTANT: Niels Dietrich CERAMIC ELEMENTS: 17,000 extruded 150 × 100 × (600, 750, 900) mm elements

150 mm

100 mm

600–900 mm

1 – Section and elevation of the extruded element. 2 – Unglazed fired extrusions.

The ceramic manufacturing process and the material properties were incorporated into this building design to achieve an intricate pattern that creates the illusion of three-dimensionality. Unlike many ceramic assemblies, the intricacies of the pattern are in the assembly logic and its relationship to the building form, rather than the color or arrangement of individual elements applied to a surface. The design of the Jewish Community Center in Mainz is a reflection on the importance of writing in the Jewish tradition. It also references the role of Mainz during the Middle Ages as a primary center for the study of the Talmud. The building form itself is an abstraction of five Hebrew letters and the grooved custom facade has a directionality that reflects the act of inscribing. The facade is a ventilated rainscreen of custom-designed extruded ceramic components attached to an aluminum substrate over a concrete structure. The facade was not initially designed to be ceramic, with the team of Manuel Herz Architects considering steel or concrete for the complex custom form. However, after studying the fabrication process ceramic proved to be the best material choice given the challenges of the very irregular pattern as well as the need for a durable material formal enough to reflect the dignity of the

PATTERNS AND AGGREGATIONS

program. According to firm owner Manuel Herz, “There is an incredible efficiency in the usage of ceramic because I used the logic of the production process of the pieces themselves, and all the geometries could be solved using just one master tile piece.” The architects worked with ceramic manufacturer NBK to produce the facade’s 17,000 600–900 mm long components using only a single extrusion die. The components are triangular, 150 mm in width and 100 mm in height, with a T-shaped groove along their base for attaching to the substructure (1, 2). These triangular components and the concentric geometry create perspectival illusions along the flat exterior walls. After winning the competition in 1999, a delay in the project ended up being a benefit, allowing the architect and manufacturer to work together to develop the facade in more detail. The building windows are parallel offsets of the outermost edges, creating concentric facade lines and eliminating the need for custom pieces around the openings (3). The beginning of each row of elements is a custom angle cut in NBK’s factory as the extrusions exit the production line (12). After the first element is installed, standard elements are assembled along the row until a change in direction. The final element of every line also has a custom angle but is cut on site

to account for any discrepancies. In order to prevent noticeable seam patterns, the standard elements were produced at lengths of 600, 750, and 900 mm, and varied as they were assembled. In this way, only the first and last components of the rows were unique, requiring numbering and specific placement. There are a limited number of unique angles in the facade meaning these “custom” cut components could still be produced in batches of several hundred (10, 11). Even so, identifying and placing the custom pieces shipped from the factory did prove to be a logistical challenge on the confined urban construction site. Designing an appropriate attachment system for the facade elements, which vary in angles from horizontal to vertical, was difficult. Ultimately, an aluminum substructure was attached to the concrete walls at right angles to the facade geometry, with a secondary aluminum substructure running parallel to the geometry (4, 5, 6, 7). The elements were then bolted to this secondary system by hangers inserted into the elements’ back groove with adhesive used as a precaution (8, 9). The substructure was designed to account for any variation in the raw construction and precisely assembled with tolerances of roughly 5 mm to accommodate the ceramic components.

3 – Elevation showing assembly pattern. Each color represents different lengths of ceramic elements.

5 – Manually adhering attachment clips.

6 – Attaching the units to the substructure.

4 – Section showing the attachment of the ceramic elements, aluminum substructure, insulation layer, and concrete structural wall.

7 – Test assembly of the final units.

91

8 – Assembly process with visible substructure.

9 – Units staged on site for assembly.

PATTERNS AND AGGREGATIONS

10 – Elements cut to various lengths.

11 – The completed facade.

12 – Manufacturer’s mock-up. Detail of the assembly joints.

93

NON-REPEATING PATTERNS

DESIGNER: 3LHD COMPLETED: 2009 CERAMIC MANUFACTURER: Florim Ceramiche S.p.A. CERAMIC ELEMENTS: Cut from 600 × 600 × 10 mm base tiles

ZAMET CENTRE RIJEKA, CROATIA

2 – Configuration pattern of the pentagonal elements and hexagonal groupings.

1 – The shapes were cut from standard rectilinear units that can be seen on the stairs and roofline.

Sometimes the challenge of complex tiling is to appear as if there is no pattern at all. For the Zamet Centre, a community complex located in Rijeka’s quarter by the same name, the architects carefully used multiple colors of off-the-shelf tiles with an efficient attachment system to tessellate roofs, walls, floors, and to create a stunning non-repeating patterned surface. Set in the city’s northwestern slopes, the Zamet Centre incorporates major sporting facilities, shopping, library, parking, and even local government offices in a 12,000 m2 site. The program is delineated by a series of ribbons that cross the site and navigate the topographic changes. The architects took inspiration from the vernacular dry-stacked stone retaining walls that have been used for centuries to carve out space from the surrounding hills,

PATTERNS AND AGGREGATIONS

and abstracted their image as a surface treatment. Ceramic was chosen as a material that could be applied as facade, roof, stairs, and floor, being lightweight enough for the roof and walls while durable enough for the floor and stairs (1, 4, 5, 10). A similar cladding in stone would have been three times as thick and more expensive. Important to the design was creating a non-directional surface pattern. Using free online software applications, 3LHD arrived at a pentagonal shape (2). With an intent to use off-the-shelf products, the Italian fabricator Florim Ceramiche was chosen: that company not only produced lines of complementary colors but was willing to cut the tiles to the designer’s specifications. Using the Architech line of Florim’s subsidiary Floor Gres, a palette of grey shades was

3 – Detail section showing the wall assembly and preassembled facade panels used for cladding.

chosen and the shapes were waterjet-cut from full-body 600 × 600 × 10 mm tiles. A texture on the surface, standard for the manufacturer, provided an R11 slip index, making the products suitable for exterior flooring and stairs. 3LHD painstakingly designed the pattern of colors by hand in order to ensure a seemingly random and non-repeating distribution. The facade system consists of four pentagonal tiles adhered to a hexagonal aluminum frame with a polyurethane adhesive—each frame’s tiles being carefully arranged according to the design (8, 9). These panels were then mechanically connected to a substructure on the facade (3). Floor and stair tiles used traditional mortar settings on concrete. From a bird’seye view, the coloring of the plaza tiles reveal the name “Zamet Centar” (6, 7).

4, 5 – The placement of the colored tiles was carefully chosen to ensure a non-repeating pattern across the facade, roof, stairs and floor.

95

6 – Site and roof plan. 7 – The Zamet Centre utilized a single system of ceramic tile as roof, wall, floor, stair, and signage.

8 – For the facade, aluminum frames were constructed for each module consisting of four pentagons.

9 – The ceramic elements were chemically adhered to the frames.

PATTERNS AND AGGREGATIONS

10 – The individual pentagonal figures aggregate to form hexagonal units.

97

FIGURATIVE URBAN MOSAICS

DESIGNER: Beyer Blinder Belle Architects & Planners COMPLETED: 2005 CERAMIC SUPPLIER: Agrob Buchtal GmbH FACADE CONSULTANT: Arup CERAMIC ELEMENTS: Approx. 10,000 extruded stoneware tiles 300 × 600 mm

MUHAMMAD ALI CENTER LOUISVILLE, KENTUCKY, USA

2 – Diagram of the assembly pattern.

1 – Approaching along the highway, a viewer quickly experiences the full range of the facade’s effects on image perception.

3 – Detail section showing the attachment system.

Part of the prohibitive aspects of tile mosaics is the scale of contemporary architecture when compared to historic buildings. Tiling the large surfaces of today’s buildings by hand with custom patterns of small square tiles is not economically feasible. The creation of figural motifs through the subtle array of individual plain colors demands a high sensitivity for proportions: while in the interior it is in most cases impossible to work with any but small-sized elements, the building envelope permits significantly larger modules due to a variable viewing distance. The Muhammad Ali Center uses colored ceramic panels to recreate photographic images across the building facade (1). The building is intended to honor the life of the legendary American boxer. Of particular importance to the museum

PATTERNS AND AGGREGATIONS

founders were images of Ali taken by photographer Howard Bingham. Architects Beyer Blinder Belle teamed with New Yorkbased design consultancy 2x4 Inc. to incorporate these images into the facade of the building, making the surfaces beacons of the museum’s purpose. While other media such as LEDs and glass etching were first considered, cost constraints ultimately led to ceramics. The graphic designers settled on a system of interlacing colored and white bands of tiles to visualize the image (2). Efforts were made to reduce the number of different colors while still creating optically interesting, rich images. The interlacing both referenced the visual language of television, which made Ali famous, as well as reduced the number of colored tiles and custom arrangements by 50% for the sake

of cost (6). In addition, the colored bands alternate between warm shades of blue and grey to warm shades of orange and red. Each color band was comprised of four colors plus white. To choose the best-suited images from his collection, mock-ups were created and viewed from a distance to test the effect. The final facade uses an off-the-shelf tile system with eight custom colors and white, mounted to an aluminum substructure (3). There are roughly 10,000 extruded stoneware 300 × 600 mm tiles. While they appear to be an abstract random pattern from up close (4, 5) from a distance the interlaced alternating colors merge visually to create a single clear image of Ali. For those driving the nearby highway, this effect is heightened approaching and receding from the building at high speed.

4 – Up close the facade appears to be an abstract arrangement of colored ceramic panels.

5 – The colored panels aggregate to form images of Muhammad Ali taken by photographer Howard Bingham.

6 – The colored ceramic elements are interlaced with bands of white ceramic elements, which create both a unique visual effect and reduce the customized assembly by half.

99

CURVED SURFACE URBAN MOSAICS

DESIGNER: Enric Miralles and Benedetta Tagliabue, EMBT COMPLETED: 2005 CERAMIC MANUFACTURER: Ceràmica Cumella CERAMIC INSTALLATION: 120,000 extruded 150 mm hexagonal stoneware tiles in 67 colors

SANTA CATERINA MARKET BARCELONA, SPAIN

1 – West elevation.

The produce found in Barcelona’s Santa Caterina market forms a vibrant pattern of rich colors. Allowing the roof to express outwardly this internal quality seems natural, and the use of ceramic tile is a strong cultural connection to the city’s history (1, 2, 13). This urban mosaic is comprised of modules of 37 large ceramic tiles that aggregate to form a single “pixel.” Built in 1848 on the ruins of a 13 th century Gothic convent, Santa Caterina is the oldest market in Barcelona. By 1997, the market itself was in such a state of disrepair that only the three existing white facades were retained in the renovation. A new undulating roof was designed to float over the site, freeing the interior of partitions and sheltering the historic walls. While the project had a complex program— two levels of parking, two blocks of housing, loading docks, space for a museum, a pneumatic garbage collection center,

PATTERNS AND AGGREGATIONS

and the market—a stunning feature is the custom mosaic that tiles the expansive roof structure; an abstract still-life of the market’s produce (7, 8). The mosaic is comprised of 120,000 150 mm hexagonal stoneware tiles produced by Ceràmica Cumella. The image itself is made of monochrome “pixels,” groups of 37 tiles arranged into a larger hexagon (3). In order to perfectly match the mural design, which contained 67 unique colors, the ceramic manufacturer conducted a long glazing study involving over 300 test pieces. Production was on a standard extrusion line. After being cut to length, a custom die stamped out the final hexagon shape (9, 10). To make installation feasible each pixel’s 37 tiles were adhered in their proper place to a fiberglass mesh designed by the manufacturer before being transported to the site (11). The topography of

the roof was mapped to indicate the location of each pixel, and specialized teams installed the meshes (4, 5). The roof structure is primarily steel overlaid with four layers of wood (6). These layers, laid crosswise, were bent to accommodate the roof surface and support the ceramic tiles. Nevertheless, due to the inherent deformation of the wood, traditional ceramic installation was not possible. After the waterproofing layer, an elastic polyurethane adhesive was used to adhere the tiles to the roof. Concerns over the movement of the tiles also led to an increased 5 mm spacing between the tiles and use of a flexible cement instead of rigid grout (12). Along the edges where the double curvature of the roof did not allow even hexagonal tiling, broken tiles were used in the Catalan trencadis style common in Barcelona and in the works of Antoni Gaudí.

2 – Undulating form of the roof.

3 – 37 tiles comprise one “pixel” in the mural pattern.

4 – Adhering the mats of tiles to the roof structure.

5 – On sloped surfaces, the mats were tied down to prevent slippage while bonding.

101

6 – Roof under construction.

9 – Extruding and die-cutting the hexagonal tiles.

10 – Glazed and stacked in the kiln for firing.

7 – Roof tile pattern showing abstraction of market produce.

11 – Adhering tiles into larger hexagon arrangements with a glass fiber mesh.

8 – Detail of the color pattern layout.

12 – Detail showing the layers of steel structure, wood structure, four layers of wood surfacing, sealant, and tiles.

PATTERNS AND AGGREGATIONS

13 – Aerial view of the market roof.

103

ROBOTIC TILING IOWA STATE MURAL AMES, IOWA, USA

DESIGNER: Eric Sealine COMPLETED: 2011 MANUFACTURER: Artaic CERAMIC ELEMENTS: Over 200,000 25 mm porcelain tiles

3 – Stacks of 300 × 300 mm grids ready for installation.

1 – Learning to Fly, original oil painting by artist Eric Sealine.

2 – Artaic robot retrieving tiles from color rows and placing them in the 300 × 300 mm grid.

4 – The ceramic mural was based on the artist’s original oil painting.

Large elaborate mosaics have always been a sign of wealth but have become increasingly expensive, especially in the developed world, due to their complexity and the cost of labor. The mosaic at the State Gymnasium pool facility of Iowa State University is comprised of 200,000 25 mm unglazed porcelain tiles covering 130 m2. It is a recreation of artist Eric Sealine’s oil painting Learning to Fly, and would have been prohibitively expensive to create by hand (1). However, Artaic, a Boston-based company providing robotically placed custom mosaics, collaborated with the artist to realize the installation (5). The process at Artaic begins with proprietary software that analyzes a digital image and translates pixels into tiles. The user selects a material, such as 25 mm unglazed porcelain tiles, and the system cross-references the array of available tile colors to best match the tile to the image. Using photographs of the tile products,

a photorealistic rendering of the final design is produced, which users can adjust to the final desirable design. The system then automatically generates the necessary robot code in order to produce the mosaic. In production, the pattern is divided into 300 × 300 mm grids, the industry-common mesh size for factory-applied mosaic tiles. In the case of the pool at Iowa State University, each of these grids contained 144 tiles. Tiles are color-sorted and loaded onto sloped tracks that ensure proper alignment as the tiles slide forward towards the robotic placement system. Using a pneumatic suction attachment, a robotic arm picks tiles from the color-sorted tracks and places them in their correct location on the grid (2). As a tile is removed, a new tile slides into its place, ensuring a continuous production flow. Tile grids are used to hold the tiles in place with the proper separation until they can be fixed in place for transport.

Robotically placing a tile takes approximately 860 milliseconds, meaning for Iowa State pool 22 minutes per square meter. The process is approximately ten times faster than human installation which, for complex designs, may average 8–9 seconds a tile. While a human could memorize repetitive patterns and thereby improve this time, the advantage of the robotic system is in complex non-repeating custom patterns that would be too difficult for a human to assemble by hand. A second-generation robotic arm will reduce the time tenfold to 86 milliseconds per tile. When placing is finished, a self-adhesive backing, either mesh or film, is applied and the units are labeled with their location in the mosaic (3). Once shipped to the job site, the installation is conventional and can be completed by local tile installers. By following the placement layout, an exact replica of the digital image is revealed full scale in ceramic mosaic (4).

PATTERNS AND AGGREGATIONS

5 – Over 200,000 mass-customized ceramic tiles form the Learning to Fly mural.

105

TESSELLATED SURFACES

DESIGNER: GGlab, Paulo Flores, and XWG COMPLETED: 2009 CERAMIC MANUFACTURER: Decorativa Tozeto, S.A. CERAMIC ELEMENTS: 520 extruded and cut elements and 150 hand-molded elements

URBAN GUERRILLA VALENCIA, SPAIN

2 – Perspectival drawing of the cladding pattern and different unit types.

1 – The polystyrene positive of the bench indicating the forms of the custom elements.

While tessellation often refers to breaking complex surfaces into a series of flat planes, ceramic tiles can also be formed to match curved surfaces. Urban Guerrilla explored both methods. This installation was a collaboration of designers from Spain, Mexico, United Kingdom, and China. Their goal was to link digital architecture with fabrication and to better understand the digital world through tectonics and materiality. The installation was located at the headquarters of the Valencia Territorial Association of Architects (CTAV) and dynamically wraps the facade features. The tessellation of the complex surface paired with its metallic glaze alters the light of the corner, making the space brighter and more inviting. The shape itself is intended to bring the facade to a more human scale, with part of the surface folding into a bench (4). As Valencia is located adjacent

PATTERNS AND AGGREGATIONS

3 – Perspectival drawing of the installation substructure.

to Spain’s ceramic industry cluster and has a long ceramic history of its own, ceramic was chosen to tile the surface. The designers worked closely with manufacturer Decorativa Tozeto to develop the elements. The digital surface was tessellated into 520 flat triangles, with the exception of the bench, which required 150 doubly curved surfaces. The flat tiles were extruded and fired, with 456 tiles wet sawcut into 14 different types; 64 of the flat tiles were unique elements. For the bench an expanded polystyrene positive was milled on a five-axis machine (1, 2, 3). Most of the 150 unique curved tiles were produced manually by applying wet clay directly to the polystyrene positive and allowing it to dry. In cases of extreme curvature, plaster molds had to be cast from the polystyrene to better control the shrinkage of up to 4% (5). Extreme or un-

even shrinkage can lead to deformation, defects in the ceramic, or even breakage. Plaster molds, which absorb moisture, assist by allowing the material to dry evenly across the surface and on both sides of the elements. All of the tiles went through a standard firing process and were finished with a gold metallic glaze. The substructure was also fabricated using CNC processes. The main structure was wood profiles cut with a 2.5 axis milling machine. The tiles were then adhered to a similarly tessellated wooden mounting surface (6). For the bench the poly styrene positive was used to adhere the tiles. Since the installation was temporary and on a small scale (7), the designers and manufacturers felt a hybrid approach of standard manufacturing with manual customization was suited to the project.

4– Street view with the flat elements on the left and upper extension, and curved elements on the lower bench

5 – Examples of the plaster molds created for extreme curvature elements.

6 – The elements were installed on a CNC-milled wood frame with markers indicating the placement for each element.

7 – Urban Guerrilla installation in 2009 outside the Valencia Territorial Association of Architects.

107

HANGING ASSEMBLIES XINJIN ZHI MUSEUM CHENGDU, CHINA

DESIGNER: Kengo Kuma and Associates COMPLETED: 2011 STRUCTURAL ENGINEERS: Oak Structural Design Office MECHANICAL ENGINEERS: P. T. Morimura & Associates Ltd. CERAMIC ELEMENTS: Traditional hand-made roof tiles 10 × 180 × (320, 390, 450) mm

1 – North elevation.

Ceramic elements can be aggregated in very non-traditional ways. Outside Chengdu, the capital of Suchuan Province in Southwest China, the Xinjin Zhi Museum sits at the foot of Laojunshan mountain, welcoming pilgrims to the holy Taoist site (1, 2). The region has been inhabited for over 4,000 years, gaining prominence 2,300 years ago as a capital city. Testifying to that history are the historic centers in and around Chengdu, marked by their traditional grey-tiled roofs, which when seen collectively create stunning man-made landscapes set against the natural beauty. Architects Kengo Kuma and Associates sought to express the essence of Taoism in Xinjin Zhi, emphasizing nature and balance. The tiles, which comprise the facade, are made from local clays and produced by hand in the traditional way. Aggregated as they are, the unevenness of the hand-crafted tiles and blemishes from the firing pro-

PATTERNS AND AGGREGATIONS

cess are readily apparent and give texture and character to the material (3). Hung from wire, the roof tiles are re-imagined as sunscreens, both shading and allowing light to pass through (4). The tiles are 10 mm thick and 180 mm wide. In order to create a gradation along the facade, three lengths were produced: 450 mm, 390 mm, and 320 mm. They are hung on a wire support structure by holes located at each corner. Each facade is subtly customized to its surroundings. To the south, it is divided vertically and set at a different angle in order to create the desired effect in each reflecting pool. To the east, the roof stretches out and the facade twists to respond to the dynamism of the road. The facade to the north is static and flat, and faces the pedestrian square. Thus while a single system wraps the building, subtle changes allow it to respond to each of the unique surrounding conditions.

In addition, multiple degrees of transparency are achieved by changing the tile configuration. Taking advantage of the many levels, the project is designed like a spiral leading from darkness into light and ultimately guiding occupants to an open view of Laojunshan mountain. Therefore at the entrance the tiles are densely placed to create a dark solid wall. Around the facade they are spaced to allow both interior daylighting and partial shade (7, 8, 9). In the teahouse, where an added layer of privacy was desired, the supporting wires run diagonally and the tiles are placed on their side (5, 6). The Xinjin Zhi Museum combines modern and traditional craft, industrial and natural materials, darkness and light, precision and variation, by finding new ways to use a ubiquitous material as ancient as its surroundings.

2 – Exploded axonometric of the space layout and position of screening elements.

3 – Traditional hand-made ceramic roof tiles, suspended across the Xinjin Zhi Museum as a sunscreen.

4 – At night, the screening effect of the ceramic elements is reversed as light pours out from the inside.

109

5 – View of two configurations, with tiles around the tea room.

6 – Attachment detail showing the three configurations of the ceramic elements.

7 – The interior effect of the screen and the reflections of the ceramic elements in the pool and glass walls.

8 – View from the east.

PATTERNS AND AGGREGATIONS

9 – The visual effect of the hanging elements is reflected in the pools of water.

111

THREE-DIMENSIONAL ASSEMBLIES

DESIGNER: Studio Odile Decq COMPLETED: 2012 CERAMIC MANUFACTURER: Graniti Fiandre S.p.A. CERAMIC ELEMENTS: 140 large-format pressed tiles 3,000 × 1,500 × 3 mm

3D×1 MILAN, ITALY

1 – Designer’s sketch of the installation concept.

Ceramic manufacturing has extended so far beyond our existing preconceptions that the idea of a 3 mm thick and 3,000 mm long ceramic tile that bends would leave many people in disbelief. For the Fuori Salone 2012 Milan Design Week, ceramic manufacturer Fiandre partnered with architect Odile Decq to showcase their large-format ceramic tile line “Maximum.” Large-format tiles have increased in popularity over the past decade, and due to advances in technology manufacturers are now capable of producing tiles larger than 3 m in length with thicknesses of 3–5 mm. These tiles are so large and thin they can be slightly bent before breaking, defying the conventional wisdom that classifies ceramic as a brittle material. By liberating the tiles from their traditional role as surface coverings, the design draws attention to the paper-thin ceramic, both its suppleness and its strength. The volume is rendered dynamic by the extraction of a conical volume cutting

PATTERNS AND AGGREGATIONS

2 – Detail of the large-format thin tiles and panel divisions.

diagonally through the layers (1, 2, 3). Here the designer’s intention was to redirect the perspective of the viewer and to influence their sense of materiality. From each viewpoint a different relationship of solid and void is experienced (4). The resulting sculpture is a cube divided into 31 slices spaced 150 mm apart. A single slice of the 4.5 × 4.5 × 4.5 m cube is comprised of four and one-half 3,000 × 1,500 mm white tiles, each with an area of 4.5 m2. The entire sculpture comprises a total 140 tiles with a cumulative area of 627 m2. In developing the assembly, the architect relied on the manufacturer’s knowledge of the flexibility and strength of the material in order to create the grid of supporting rods. Threaded steel rods were assembled in segments on a 500 mm grid in order to provide stability to the structure. White steel tubes were placed around these rods to act as spacers ensuring each layer was exactly 150 mm apart (5).

Pressed tiles have been limited in size due to air trapped in the tile body when the loose powder is compressed. If left in the body, the pressurized air could expand and cause breakage during firing. To avoid this tiles remain under pressure long enough for the air to evacuate through the body. However, the time required to evacuate the air increases as the surface area and thickness of the tile increases. This is not economical given the modern production rates of tile manufacturing lines and hence most pressed tiles remain under 1 m. Several companies have developed proprietary production lines capable of overcoming these challenges. Some replace the traditional pressed-mold method by compacting the dry powder under belts, others pre-compact the dry powder under belts in order to evacuate the air, but then finish the process with a second compaction using a traditional mold press. New possibilities are opening for large-format tiles and aggregations that free them from their substrates.

3 – 3D×1 installed at the Fuori Salone 2012 Milan Design Week.

5 – Threaded steel rods run inside white steel spacers to keep the structure stable.

4 – A conical volume is cut from the regularity of the grid.

113

STRUCTURAL ASSEMBLIES

DESIGNER: Kengo Kuma and Associates COMPLETED: 2010 CERAMIC MANUFACTURER: Casalgrande Padana S.p.A. CERAMIC ELEMENTS: 1052 600 × 13 × 1200 mm

CASALGRANDE CERAMIC CLOUD (CCCLOUD) REGGIO EMILIA, ITALY

pressed tiles cut to length

1 – South and west elevations.

Conventional wisdom has always taught that the brittleness and compressive strength of ceramic make it a poor material to put in tension. However, new production techniques are changing the material properties of ceramic as well as our understanding of how they function structurally. The CCCloud incorporates off-the-shelf ceramic tiles with steel structures to create a sculptural work of ceramic tile art free from substrates. The construction of a roundabout outside the ceramic tile manufacturer Casalgrande Padana’s headquarters created an ideal location for a monument (1, 2). The site, in the satellite town of Casalgrande, marks the entrance to the Sassuolo ceramic tile district, the industrial center of the Emilia Romagna region of Italy. As the home of 300 ceramic tile manufacturers, it is one of the largest ceramic tile districts in the world. Funded by Casalgrande Padana and supported by municipal authorities, the monument clearly needed to feature ceramic tiles. It took the form of an artificial “cloud,” a 5-m-tall ceramic curtain floating in a reflection pool. Located in a rural setting outside the town, the monument was designed to be experienced by automobile. It is aligned with the axis of the

PATTERNS AND AGGREGATIONS

main road, making it appear thin, less than 2 m thick, along the approach, yet revealing its full 45 m length as cars enter the roundabout. In addition, the angles of the tiles change along the length, creating a moving point of transparency as the viewer circles (12, 13, 14). Using an off-the-shelf, white, unglazed stoneware element produced by Casalgrande Padana, the construction method liberates the monument from the traditional concrete substrate in order to give it lightness and transparency. The structure is comprised of 526 elements, each consisting of two 600 × 13 mm pressed tiles with varying lengths up to 1200 mm. The tiles are produced with a textured back to improve mounting adherence; in order to have finished surfaces on both sides two tiles were laminated together with fiber mesh and epoxy adhesive (9). Radial saws were used to cut two slits in the sides of the panels to attach the plates of 30 × 30 mm steel profiles (10, 11). The steel profiles have an 18 mm diameter hollow core through which runs a 16 mm diameter rod. This rod was constructed in sections as the panels were slid on, but extends the full 5 m height of the structure (3, 4, 5, 6). After the final tiles were put in place, each

rod was post-tensioned to ensure the continuity of the load. Once in compression, the ceramic elements act as the primary structural support of the system. Neither the engineers acting as consultants to Kengo Kuma Associates nor the local engineers—both using different techniques—were able to create models that accurately represented the complex and novel structure that relied on laminated ceramic tiles for stability. While it extended the pre-construction phase, several mock-ups 3 m tall and 7 m long were created to test the system. Initially intended to merely verify the construction and assembly process, more and more sophisticated equipment was used to test the structural properties. Mechanisms applied specific force while measuring deflection. These were then compared with the deformations of the engineers’ structural models to verify they reflected reality. The process was a back and forth between the abstract and the physical, but ultimately the mockups proved the system worked. Additional time was also spent on the precision of the foundation. There was no margin for error in the ceramic panels, and the location of the vertical supports had to be aligned to the millimeter.

2 – When viewed on angle, the structure appears opaque.

115

3 – The vertical supports were installed first, with little margin for error.

4 – The panels then slid onto the vertical supports by way of the attached hollow rods.

5, 6 – The ceramic panels are held in compression by the pretensioned steel profiles.

7 – Section and elevations of the ceramic panels with vertical connectors.

9 – Each panel is made of two ceramic elements laminated together.

PATTERNS AND AGGREGATIONS

10 – Slits are cut into the laminated panels.

8 – Panels joining at a fix angle around the steel tubes.

11 – Adhesive was used to ensure a strong connection with the vertical structural profiles.

12 – The CCCloud, commissioned by Casalgrande Padana, marks the entrance to Italy’s ceramic manufacturing region.

14 – Plan of the roundabout reflecting pool and CCCloud.

13 – As one traverses the traffic circle, side views of the structure present an open screen.

117

CHAPTER 10

THERMODYNAMIC SKINS The quest for comfortable yet environmentally sensitive living environments has never been more pressing. Buildings have long relied on an increasingly complex technical infrastructure to maintain comfortable indoor environments. Construction systems have become more complex to meet energy and safety standards. This is particularly evident in the design and construction of building envelopes and roofs that have transitioned from solid timber, stone, or brick walls to multilayered assemblies of building products and materials. Their layering and interconnection may satisfy codes and operational needs, but disassembly and reuse are rarely considered and all too often extremely difficult. Far too little attention has been given to the powerful role material systems themselves can play in the quest to balance occupant comfort with low life-cycle environmental impacts. By designing building skins with fewer but more thoughtfully configured material systems, designers can potentially simplify the overly complex mix of products and materials. An end goal could be a new simplicity of construction, the design of highly performative skins that are capable of disassembly such that materials can find a second use once the building reaches the end of its useful service life. This chapter presents several innovative strategies that illustrate the role ceramic systems can play in advancing this agenda. Special emphasis is on daylighting and thermal issues, as well as combinations thereof. Some are more mature than others, and all together provide but a glimpse of the opportunities inherent in fired clay. Ceramics have long been used as a modulator of humidity and thermal performance. Ceramic water bottles have cooled water for centuries by evaporative cooling through the vessels’ ceramic walls. Roman engineers deployed ceramic channels to guide hot air to radiate heat into a spa’s floors and walls (1). Ceramic stoves and stove tiles have long modulated the intensity of wood and coal fires, to keep occupants warm in cold weather. Modern chemistry, material science, advances in industrial processing, and the inventiveness of design teams are now enabling these and other historic precedents to function at larger scales and in more predictable ways. The recently improved scientific understanding of the material and today’s highly controlled processing technologies now allow producers to directly design the material properties for maximized environmental benefits. Computational simulation is a key enabling design technology that allows design teams to rapidly evaluate the performance of alternative solutions. As is evident in the case studies, prototyping and testing remain crucial aspects of the design development process. Today’s ceramic systems enable some of the most innovative—yet remarkably simple—thermodynamic skins in buildings. A key variable in the material design of ceramics is porosity. It impacts the all-important water absorption of ceramic elements (thus affecting durability), influences resistance to heat flow and specific density. In the context of this chapter, porosity is of particular interest in buildings that deploy ceramic as a medium for evaporative cooling strategies. These systems utilize the evaporation of water through the ceramic elements themselves as a way to lower ambient air temperatures, at times with simple mechanical ventilation systems. The absorption and evaporation is facilitated by appropriately porous ceramic material. Porosity can be controlled through the actual material mix of the clay body, as well as through firing sequences and temperature. Longer kiln firing at higher temperatures creates denser, less porous ceramic, whereas adding grog or other materials increases porosity. Experimental research even investigates the role of burn-out strategies whereby sawdust, foam, or other inflammable materials are mixed in with the clay (2). During firing, the flammable aggregate burns, leaving small voids behind that form the desired foam-like matter. Numerically controlled mixing systems, combined with the experience of craftspeople, enable the tight control of material porosity and its related water absorption in almost any production setting today. Evaporative cooling with ceramics is not

Trier

470 mm Naples

510 mm

1 – Roman tile models shaped to form an interstitial space when the protruding back element is halfembedded into a masonry wall. Hot air channeled through the air layer heats up the tile and heat radiates to the occupants.

2 – Porous ceramic structures with pores in the millimeter range improve thermal resistance and absorb sound.

Pompeii

540 mm

d = 20 mm

new, but technological advancements now allow for this simple principle to scale up from the size of small portable vessels to building scale and beyond. The large ceramic cooling facade for the Sony Center in Tokyo, for example, has demonstrated cooling effects on its adjacent urban microclimate. Specific heat capacity and thermal resistance of ceramics have always been of keen interest when ceramic elements were used to radiate heat—in floor heating, stoves, or freestanding ceramic radiators common before cast iron and then steel replaced ceramics. Glazes also play a significant thermodynamic role. This highly sophisticated and quickly evolving field has produced an immense variety of materials with a wealth of properties, many of which impact how ceramic elements interact with heat, water, and light. Reflective light-colored glazes, for example, can significantly reduce the amount of energy absorbed from incoming solar radiation, potentially reducing cooling loads. This is particularly true for elements applied on inclined roofs, but is also relevant for facades. Special shaping of ceramic facade elements can contribute to reducing heat flux through the outermost layers, especially when combined with reflective light-colored glazes applied on areas exposed to the sun. Initial tests on solid, brick-like elements show a 10–15% reduction in heat flux compared to traditionally flat elements.1 While exact amounts will vary depending on geometry and climate, the ability of ceramic producers to generate custom shapes designed for specific sun exposures and locations creates a particular interest in self-shading ceramic systems. Their effect, however, is likely most significant if elements are directly adhered to a rigid masonry or concrete wall, thus without a ventilated cavity. Maybe the most obvious benefit of shaping ceramic elements is their ability to control incoming daylight. Here the ease of customizing cross-sections, adjusting the spacing of sun-shading lamellas and their inclinations produces a broad range of design opportunities. Alternative systems in metal often appear highly technical and somewhat cold. Ceramic sun control systems, however, continue the tradition of a visually warm and welcoming material family that integrates well into the landscape and cityscape. Extruded elements are most commonly used, and colored glazes can further expand their ability to reflect, diffuse, and control the amount and quality of natural light. This chapter includes several case studies with a focus on daylight control.

NOTE 1– Andreani, S. (Re)volving Brick. MDesS Thesis. Cambridge, MA: Harvard University Graduate School of Design, 2013.

The longevity of ceramics has obvious advantages in reducing life cycle impacts, but the downside is often seen when older tiled surfaces appear aesthetically outdated and are thus demolished despite being in technically good condition. The robustness of the material theoretically allows for ceramics to be reused, provided that disassembly is economically and technically feasible—here the industry is challenged to find ways to facilitate the removal of adhered tiles. In the meantime the use of factory stock of discontinued tile models provides a glimpse of the design opportunities inherent when newly composing overall patterns from tiles that might individually prove less appealing, even dated, in their appearance. The Ceramic Pixel case study illustrates the renewed interest of designers and artists in exploring tiles as “found objects.” The first case study on the refurbishment of a disused warehouse plays with our perception of roof tiles by removing existing tiles from their original context and re-purposing them. Doing so not only gives greater value to an otherwise ordinary, ubiquitous building product, it also challenges established notions of ceramic material systems and their context.

119

RECLAIMED TILE TECTONICS

DESIGN: Arturo Franco COMPLETED: 2008 CERAMIC MANUFACTURER OF ORIGINAL ROOF TILES: Francisco Ramón Borja S. A. CERAMIC ELEMENTS: Approx. 700 m2 reclaimed ceramic roof tiles, model 5 A

WAREHOUSE 8B ADMINISTRATIVE OFFICES MADRID, SPAIN

2 – Warehouse roof tile.

1 – Material flow.

The longevity of ceramics remains one of the most compelling arguments for their use, especially in applications where they are exposed to the elements. The same property, however, is also significant when considering material reuse in the context of existing construction. Roof tiles are of particular interest because they are easy and fast to remove when compared to adhered tiles, containing little or no contamination from mortar or adhesives that would require laborious removal procedures (1). The intricate geometry of roof tiles, however, makes their reuse in anything but the same application challenging (2). When the slaughterhouses of Madrid were moved to the outskirts of the city, the original compound, designed in 1907 by Luis Bellido, remained unused for almost 30 years. In 2005, the Arts Council of the city decided to renovate the building and convert the compound into a cultural center. Building 8B was to house the new administrative offices for the center. The program was simple, focused on stabilizing the structure, replacing the dilapidated roof structure, and creating an acoustically

THERMODYNAMIC SKINS

and thermally comfortable work environment (3, 4, 5, 6). The design was inspired by the roof tiles, which remained in overall good condition despite having protected the building for approximately 60 years. Other unused building materials such as timber beams and tiles were piled up in the empty warehouse, suggesting their possible reuse. Franco was interested in a contemporary conversion project, yet wished to maintain the character of a building that forms an integral part of Madrid’s history. The roof elements were carefully removed and sorted manually (7, 8). The roof tile model 5 A had been widely used in Spain and remained in production for decades. Very few tiles, approximately 0.5 m3, were defective and could not be reused. They were ground up on site and mixed with the mortar used to construct the new tile walls. All other tiles were stored on site for masons to construct non-loadbearing interior partitions and wall facings. Details and aggregation patterns were discussed and developed directly on site between the architect and the masons.

The tiles were bonded with standard cement-based mortar. During installation the masons checked each tile again for defects. Wall facings were made from tiles cut in half along their length, thus reducing construction depth, increasing the number of tiles available, and maximizing the available interior space. Every four to five rows the cut tiles were connected back to the structural wall using steel ties. Freestanding tile partitions were anchored to the structural steel at the top every two meters using steel U-profiles. By only partially embedding tiles in mortar, the masons created porous conditions and established lattice-like openings that allow for views while maintaining the visual continuity of the tile wall. The origin of the tile elements only becomes apparent at a second glance—their intricate detailing, usually hidden from view, plays out as an ornamental feature (9, 10). A lap joint detail was developed to produce corners with interlocking tile layers, inspired by similar joints used in the timber construction on site.

3 – Reclaimed roof tiles line the interior walls.

6

4 3 2 1

4 – Section.

4 3 2 1

5 – Plan.

121

6 – Screen wall.

7 – Tile removal.

8 – Storage of tiles waiting to be reinstalled.

THERMODYNAMIC SKINS

9 – Intricate lattice pattern.

10 – Circulation space.

123

GRÃO – CERAMIC PIXELS

DESIGNER: Pedrita CERAMIC MANUFACTURER: Various COMPLETED: 2012 CERAMIC ELEMENTS: 559 tiles 150 × 150 mm

JARDIM BOTÂNICO TROPICAL TRAVESSA DO MARTA PINTO BELÉM/LISBON, PORTUGAL

1 – Urban strategy.

Often overlooked is the large ceramic tile market for used, waste, leftover, and factory second tiles that exists all around the world. These tiles, collected from closing factories or leftover from construction sites, gain value as they are stored in warehouses, becoming rare. They are most often used in repairs when property owners, searching for replacement tiles, are directed by tile manufacturers to the collection companies. Architects Pedro Ferreira and Rita João, founders of Pedrita, developed another method to bring new life to these warehouses of discontinued industrial tiles. In Portugal, a country with a long history of decorating buildings externally and internally with tiles, Pedrita partnered with the largest end-of-life tile reseller to create large murals from photographic images (1). The project’s name, Grão, literally “grain,” is taken from the grain of photographs and refers to how each reclaimed tile is used as a pixel in the larger mural. The process begins by consistently photographing the stocks of tile available

THERMODYNAMIC SKINS

2 – Rendering of tile mosaic.

in order to ensure accurate color capture and luminosity. Off-the-shelf image processing software is used to create a reproduction of a digital image from the tile photographs (2). The panels are then manually dry-assembled in the studio in order to visually test the results (3, 4). Some stocks of tiles may be limited; others, as industrial seconds, have an inconsistent color or format. Adjustments at this stage are based on the human eye. The designers describe the process as half manual and half digital, using industry standard software. Once the result is satisfactory, the tiles are either numbered and packaged for traditional onsite installation, or assembled into panels for temporary installations. The murals are comprised of standard format 150 × 150 mm tiles; however, different manufacturers over the decades have varied by 3 mm, from 149–152 mm. This adjustment is accounted for during installation by varying the grout lines of the tiles. The murals are significantly more expensive than standard tile installations, not only because of the

design process but because they consist of rare, discontinued tiles already priced higher. A proof of concept for Grão was first exhibited in the National Tile Museum in Lisbon in 2007. In 2012, a large installation of a Muscovy duck was installed on the wall of the Jardim Botânico Tropical in Lisbon (5, 6). The installation is made up of six pretiled panels assembled on site with a total of 559 150 × 150 mm tiles covering an area of 4.5 × 5.5 m (7, 8). While the image of the duck is visible from the end of the perpendicular Travessa do Marta Pinto, along the approach the same image recedes as the visibility of the individual tiles increases. Pedrita notes the significance of the emotional connection between people and the installations, a connection that transcends the mere recognition of the image. As the murals are comprised of hundreds of different discontinued tiles collected locally, many viewers identify some among them, and relate them to their personal memories of spaces they once inhabited.

3 – Test assembly.

4 – Mock-up.

5 – Close-up.

6 – Finished installation.

1 2 3 4

5

6 1 – 150 × 150 mm tile 2 – Metal anchor 3 – Galvanized steel profile 40 × 40 mm 4 – Polycarbonate panel d = 8 mm 5 – Silicone 6 – Galvanized steel U-profile 7 – 10 mm steel bolt 8 – Galvanized steel profile 40 × 40 mm 9 – Galvanized steel flat 5 × 60 mm

7

8

9 7 – Installation on site.

8 – Installation system and detail.

125

MASONIC LOUVERS

DESIGNER: Perkins+Will CERAMIC MANUFACTURER: Boston Valley Terra Cotta

STUDENT SERVICES BUILDING UNIVERSITY OF TEXAS AT DALLAS, USA

FACADE CONSULTANT: Curtainwall Design Consulting (CDC) COMPLETION: 2010 CERAMIC ELEMENTS: Nine different models, altogether 3,756 elements, typical dimension 1,821 × 157 × 49 mm

152 mm

157 m

m

89 mm 49 m

m

1.929 mm

1 – Facade section with shading strategy.

2 – Typical ceramic elements. The end pieces were removed before shipping.

Ceramic elements are of particular interest for external shading systems in that they combine durability with a wide range of color options, always maintaining a warm, non-technical aesthetic that can soften the often harsh visual appearance of external shading lamellas. The sunny climate in Texas makes external shading a must, especially if extensive use of glazed surfaces is desired for transparency and views (1). Temperatures during the summer routinely exceed 37°C (100°F), and drop below freezing in the winter. The student service building, the campus’ first ever LEED Platinum-certified building, communicates openness and offers a sense of welcome, yet maintains a “masonic” look that integrates well into what was perceived to be the dominant aesthetic of the campus architecture. The task was also to maximize the number of workplaces with views toward the exte-

rior. The achieved energy efficiency is 41% better than ASHRAE 90.1, and 50% more efficient than the average of all buildings on campus. Large glazed areas were needed but solar gain had to be controlled through an efficient exterior shading strategy. To maintain visual lightness, a pretensioned rod system suspends the ceramic extrusions of various lengths from steel outriggers anchored to the structure (2). The density of the lamella pattern corresponds with the various facade exposures, and accommodates views where needed while controlling solar gains. Louver spacing is less dense where occupant and pedestrian views need to be maintained (3, 4, 5, 6). Specific louver patterns were assigned on different facades, guided by computational daylight simulations. In the final version, 76% of all occupied spaces have natural daylight, and 93% have views towards the outside. The operational

THERMODYNAMIC SKINS

building turned out to be 63% more energy-efficient than the average of all campus buildings. Working in collaboration with Boston Valley Terra Cotta, the designers developed a custom profile that met the aesthetic preferences and satisfied the shading criteria. The hollow profile was designed to accommodate the concealed horizontal stainless steel rod assembly as well as aluminum end brackets for enhanced structural capacity. A wet-pressed end piece caps the hollow extrusion and provides the unusually solid “masonic” appearance of the louvers (7, 8, 9). The custom stainless steel vertical and horizontal suspension system features threaded steel rods connecting to small aluminum brackets, which in turn support the ceramic elements. The rods are post-tensioned to reduce lateral displacements from wind and other lateral loads over the 12 m height of the facade (10).

3 – Lobby space.

4 – Ceramic louver system at the student center.

5 – Ground floor plan.

0

127

30

6 – The system balances sun protection with views.

1 – Stainless steel rod 2 – Ceramic extrusion 3 – Silicone profile 4 – Aluminum bracket 5 – Wet-pressed ceramic end cap

1 2 3 4 5

7 – Exploded system view.

THERMODYNAMIC SKINS

8 – Close-up view.

9 – Corner detail.

10 – Post-tensioning rods provide an almost invisible support structure.

129

MODULATING LIGHT

DESIGNER: James Carpenter Design Associates Inc. (JCDA) CERAMIC MANUFACTURER: Moeding

ADDITION TO THE ISRAEL MUSEUM JERUSALEM, ISRAEL

Keramik fassaden GmbH COMPLETION: 2010 CERAMIC ELEMENTS: Three profiles for shading elements with lengths from 640 to 2,975 mm, typical length 1,440 mm, approximately 7,000 elements

48

m

m

50 mm

79 mm 68 mm

224 mm

50 mm 550 mm

1 – Exploded system view.

Unique opportunities arise when shading and light redirection are combined to shape customized louvers that literally sculpt light, almost materializing it as a spatial medium. This approach was taken by James Carpenter Design Associates Inc. in their thoughtful yet restrained design for an addition to the Israel Museum in Jerusalem. The existing museum buildings, designed by Alfred Mansfeld and completed in 1964, had addressed the challenging local sun exposure by locating small clerestory windows higher up. This solution cut out most of the strong sunlight but provided limited control. JCDA chose a radically different strategy by conceiving a completely transparent glass pavilion and surrounding it with a layer of louvers such that incoming sunlight is partially reflected and partially redirected to the ceiling, thus indirectly lighting the interior (1, 2, 3). The distance between glass and shading elements is normally 1.5 m, enough to allow for the sunlight to project color traces of the surrounding landscape onto louvers and glass. At the entry this interstitial space opens up and becomes occupiable, creating a semi-interior environment with the warm materiality of the gray glazed ceramic louver pattern on one side and the transparent glass on the other side.

THERMODYNAMIC SKINS

1.290 mm

2 – Typical ceramic element.

JCDA is known for the masterful handling of transparency and light. Key for the Israel Museum addition was the ability to design project-specific shading screens that would completely block out the intense Middle Eastern sunlight, while preserving a sense of connectedness with the surroundings. The designers initially favored a louver version made from high-strength fiber concrete, but ultimately selected ceramic because of its lower unit-weight and cost advantages. Ceramic’s slight variations in color and texture were a secondary reason, assuring a material-based connection to the natural surroundings and creating visual warmth in contrast with the neutral and more technical glass enclosure. Computational ray-tracing studies were used to analyze and design foilshaped louvers for the different facades (4). Two sets of ceramic shading elements were eventually developed, one for the east and west elevations, the other for the south-and north-facing surfaces. The cross-sections were optimized as a hollow form ideal for extrusion processes, and additional ceramic elements were developed as wall claddings. The shading elements are relatively slender and span up to 2.9 m, necessitating extruded aluminum profiles to be inserted into the hollow ceramic

extrusions to provide additional structural capacity. The German fabricator Moeding Keramikfassaden completed the final design of the combined ceramic/aluminum system in collaboration with JCDA and the aluminum contractor Alumeyer. Moeding’s engineers designed a custom clay body (3% water absorption) that satisfied the designer’s expectations for color, haptic quality, and surface granularity. A series of aluminum end caps were added to the elements, tied together along the internal aluminum profile. The end caps include rectangular slots that slide into matching pieces mounted on the mullions during the installation process. This approach guarantees that the correct inclination angle of the louver relative to the sun is reliably maintained (5, 6). The aluminum hardware was assembled with the ceramic shading elements prior to shipping from Germany to Israel. The end caps provided good protection against chipping of the ceramic, and the pre-assembled elements could be quickly mounted onto the mullions on site. In the final building, the overlapping louvers produce a soft daylight quality with indirect reflections and a hint of patterns from the surroundings, displaying on the ceramic surface (7, 8, 9).

3 – Interstitial space between ceramic and glass layers.

4 – Ray-tracing study.

5 – Full facade mock-up.

6 – Mock-up.

131

7 – Addition by JCDA.

8 – Ground floor plan.

THERMODYNAMIC SKINS

9 – Interior view.

133

PERFORATED SLAB

CERAMIC PRODUCTION: Locally

SCHOOL LIBRARY GANDO, BURKINA FASO

clay pots without bottoms, diameter up to

1 – Plan. 2 – Sections.

Skylights are a common strategy to provide daylight for deep interior spaces that cannot receive sufficient natural light through facade openings. In hot climates such as that of tropical zone Burkina Faso, however, roof skylights quickly lead to overheating due to the extreme solar radiation, and sand storms might quickly reduce their optical quality. Berlin-based Kéré Architecture sought to overcome this challenge by designing a layered roof envelope that shields openings in the concrete roof slab with a metal roof spaced apart such that indirect light illuminates the interior. The building forms part of an extension to a school designed by the same architects and completed earlier. The library closes a corner between the existing school and its extension, also sheltering the schoolyard from dusty winds. Load-bearing walls are made from compressed earth blocks, and the horizontal enclosure is formed by a concrete roof with playfully positioned openings formed through clay elements (1, 2).

THERMODYNAMIC SKINS

DESIGNER: Kéré Architecture COMPLETION: 2011 CERAMIC ELEMENTS: Approximately 230 800 mm, wall thickness 10–20 mm

3 – Transport to site. 5 – Cutting off the bottoms.

The corrugated metal roof covers the entire building, providing shade and protecting the interior from rain during the wet season. Selected roofing areas are covered with translucent roofing material to augment the amount of daylight for the library. A solution for the skylights was found by tapping into the local pottery tradition instead of purchasing costly industrial products. Clay liners were produced that form the openings while pouring the slab. There was no need to seal the skylights—leaving them open provided a welcome source of air movement. The average daily high temperatures in Gando range from 25–32°C. During the day the metal roof surface heats up quickly and draws up air through the clay-lined openings in the concrete slab. The effect improves air circulation and thermal comfort in the library, making the space more conducive to reading and study. The clay elements are segments from traditional pots made locally by women from the village, with wall thicknesses of approximately 10–20 mm (3). The pots are

4 – Clay pots on site. 6 – Moving pots for installation.

dried in the hot sun and not fired, due in part to the lack of fuel sources.1 Clay pots of varying sizes were produced and carried to the site where the bottoms were cut off by construction workers (4, 5, 6). The open-ended, bellied clay shapes were then placed on the flat concrete formwork, with reinforcement bars in between (7). Upon casting the 100 mm deep concrete slab, clay and cement formed a strong bond, and there was no need to remove the clay pots, which effectively act as permanent formwork (8). The clay surface appears as a liner in the concrete, its smoothness juxtaposed with the exposed concrete surface, pleasantly filtering indirect daylight in the interior (9, 10). The ensemble maximizes efficiency with minimal system and material effort.

1 Sun-dried clay would not be considered ceramics by our definition—this case study was included nevertheless because the lack of firing has little impact on design and performance.

7 – Pots are placed on concrete formwork.

9 – Exterior view, under construction.

8 – Poured concrete bonds well to the clay elements.

10 – Interior view.

135

COOL CAVITY

DESIGNER: Javier Terrados Cepeda CERAMIC MANUFACTURER: Decorativa Tozeto S.A. COMPLETION: 2012

PATIO 2.12, ANDALUCÍA TEAM SOLAR DECATHLON EUROPE 2012, 2ND PRIZE, MADRID, SPAIN

CERAMIC ELEMENTS: 432 terra cotta extrusions; 800 × 397 mm tiles, diameter 20 mm, wall thickness 6 mm

20 mm 800 mm 397 mm

1 – Ceramic elements.

Technologies for cooling usually involve a mechanical chiller unit or other heat exchanger that cools down air or water, which in turn is utilized to lower the indoor air temperature through a variety of heat exchange interfaces. The energy needed to operate these or similar systems can be significant. The use of natural evaporative cooling in combination with porous ceramic water absorbers offers an alternative. The 2012 Solar Decathlon provided a welcomed test bed for a small working prototype— Patio 2.12. This competition entry by four Spanish universities won second prize in the international competition among universities for the most resource-efficient house that takes best advantage of solar energy. The house was collaboratively designed by 20 investigators and 50 students from the universities of Sevilla, Granada, Málaga, and Jaén (1, 2). The name—patio is Spanish for courtyard—reveals the fundamental concept. The traditional Mediterranean courtyard typology guided the layout, which features four prefabricated modular spaces arranged around a multifunctional, enclosed courtyard (3, 4, 5). Two spaces, the living room and the kitchen, are located on the northern side of the patio, whereas the bedroom and a technical space are located on the southern side. The courtyard itself provides a breathable, glazed and shaded buffer zone connecting all spaces into a house of just under 70 m2 (6, 7).

THERMODYNAMIC SKINS

2 – Computational fluid dynamics study of interior airflows.

The environmental design strategy includes a plethora of connected systems that range from photovoltaic panels, water management networks, and layered daylight control systems to a hybrid climate control strategy that combines natural ventilation and mechanical systems. The building is designed for an installation in Madrid with its hot, dry summers. Success hinges on finding and implementing an energy-efficient cooling strategy. The team developed a ventilated facade clad with custom ceramic panels devised to cool incoming air, using the age-old principle of water evaporation. The use of water-absorbent ceramics was inspired by the Spanish bo­ tijo, a traditional ceramic drinking vessel used for cooling water. The ceramic walls of the botijo absorb a small amount of water, which then evaporates to the outside. The energy needed to transfer water from a liquid to a gaseous state reduces the temperature of the ceramic, effectively cooling the water in the container along with it (8, 9). Patio 2.12 deploys custom-produced, hollow terra cotta extrusions as the core strategy of a multifunctional cladding system. The facade panels on the northern facades were activated for evaporative cooling, and are filled with mineral wool. A drip system at the top moistens the interior of the panel, and as the water trickles down it is absorbed into the ceramic. Horizontal panel joints between the 800 mm long

extrusions are bridged by an elastomeric insert to prevent water leaking out at the seams. The cooling principle is similar to that of the botijo. Water is absorbed by the porous facade elements, which in turn are cooled as the water evaporates. The lower surface temperature of the cladding in turn cools the air in the cavity space. At the bottom of the cavity, the cool air is mechanically drawn to the interior space. The system is self-controlled by temperature sensors inside the cavity. The air is only drawn to the interior if the temperature inside the facade cavity is lower than the interior temperature. During a hot day, cool air is thus naturally provided by only using small electrical fans and water. The extraction of warm air from the interior takes place through solar chimneys. Here the sun heats an inclined mechanical duct and hot air moves up through a stack effect, drawing air out from the inside. The ceramic extrusions feature a deep wave texture on the outside to increase the surface area available for evaporation (10). Produced from porous terra cotta with 10% water absorption, the ceramic panel surface facing the ventilated cavity is coated with a polyurethane waterproof layer to prevent the transfer of humidity to the cavity air. Most of the evaporation thus takes place on the outside, and the cooled air remains dry for improved indoor comfort.

3 – Exterior view of north facade.

5 – Interior ceramic cladding.

4 – North-south section.

137

10 – West facade with integrated openings.

139

BREATHING COLUMNS SPANISH PAVILION AT THE INTERNATIONAL EXPOSITION OF ZARAGOZA, SPAIN

DESIGNER: Mangado & Asociados S.L. SUSTAINABILITY CONSULTANTS: Iturralde y Sagüés Ingenieros, Fundación CENER-CIEMAT CERAMIC MANUFACTURER: Decorativa Tozeto S.A. and Ceràmica Cumella ENGINEERING CONSULTANT CERAMIC FASTENING SYSTEM: Disset COMPLETION: 2008 CERAMIC ELEMENTS: 25,000 terra cotta extru-

150 mm

sions; 14,000 semi-circular pieces 200 × 831 mm, and 14,000 larger pieces 310 × 831 mm

1 – Ceramic elements with breakout sections for stability during drying and firing.

300 mm

Evaporative cooling can be effective beyond lowering indoor air temperatures in buildings. In fact, a well-known feature of landscape design is the use of water pools to lower temperatures in the immediate surroundings. The design of the Spanish Pavilion for the 2008 International Exposition at Zaragoza features such cooling pools, but also includes an innovative area of breathing columns designed to maintain comfortable conditions for the typically long lines of visitors wishing to gain access to the pavilion. The building was the winning competition entry by architect Mangado & Asociados (1, 2, 3, 10). The competition brief not only called for a building with low operational energy but also limited the embodied energy of entries to 110 KWh/m2, thus encouraging the use of local materials with high recycled content. Mangado’s design conceptually references a bamboo forest that consists of closely spaced steel columns clad in terra cotta extrusions. The columns support a large roof canopy that shades the building and its surrounding water pools (4). The western perimeter of this outdoor environment features closer column spacing that provides more shade in the afternoons. For the main entry on the eastern side, the design team devised a breathing ceramic column cladding that locally controls outdoor temperatures through evaporative cooling. The overall environmental concept of the building was developed in collaboration with the Navarro-based Bioclimatic Architecture Department of the Renewable Energy Centre (CENER). Inspired by the use

THERMODYNAMIC SKINS

of porous terra cotta containers to cool drinking water stored in buildings, the Zaragoza system is conceived to follow a similar principle albeit on a larger scale. Rainwater is collected on the roof and guided through the columns into the reflecting pool underneath the canopy. This water basin supplies the evaporative cooling system located on the eastern perimeter where it surrounds the entry passage through the outdoor space into the interior. Misting nozzles located at the top of the columns produce a continuous film of water running down the smooth inside surface of the terra cotta extrusions. Once the entire ceramic surface has been moistened, the water supply is cut off and air is mechanically blown from the top down towards slots in the ceramic elements. These cladding elements, saturated with water, are relatively porous to allow for the evaporation of water that cools the air flowing down. The cooled air exits at pedestrian level through slots cut in the ceramic elements, producing a cooling effect that increases the comfort of individuals in the shaded outdoor space. Once the ceramic elements have dried out, the cycle restarts with renewed water misting at the top. During the design phase computational fluid dynamic simulations were used to verify the effect (5). The terra cotta elements are 12–23 mm thick and 831 mm long. Both manufacturers combined extruded approximately 100 pieces each day. The architects welcomed the slight color variations between different pieces that, for them, emphasize the natural origin of the ceramic material and align the appearance naturally with the

bamboo metaphor. During the design development process much time had been spent to evaluate clay tones through prototypes. The clay body has grog added to increase the porosity to 10%. To compensate for its shrinkage of 6% during the drying and firing process, all dies were scaled up—thus the 300 mm diameter pieces were extruded with a die diameter of 318 mm. Different extrusion dies were fabricated to produce semi-circular elements with a ribbed outer texture (6). Inner support elements were broken out after firing—they merely helped to avoid distortions of the drying pieces prior to firing (7). Directly after the extrusion, the pieces were cut to length before drying for approximately five days. The firing process was extremely slow, taking 56 hours at temperatures of 960–1,030°C. To ensure stability during the drying and firing process, the extrusion included a system of radial elements designed to easily break out after firing. Many elements did not show clean end profiles, especially those that had been fired vertically. A precision saw was used to further trim the pieces and achieve a satisfactory quality. After production the exterior of the extrusions was coated to improve their weather resistance. Slots in the ends allow mechanical hooks to hang the ceramic elements from the interior steel columns (8). The connecting elements, developed in collaboration with the engineering firm Disset—specialized in ventilated facades—were designed to minimally reduce air and water flow through the interstitial space between the ceramic element and steel column (9).

2 – View from the south.

3 – Entry level plan.

N

0 1 2

5

10 m

141

81,0 0,6

4 – Densely spaced column network.

81,0

5 – CFD study on cooling airflow.

17,8 30,0

21,9 30,0

6 – Detailed column plans with interior steel structure and drainage pipe.

7 – Extrusion during manufacturing.

THERMODYNAMIC SKINS

8 – Connection detail.

9 – Exploded column diagram.

10 – Entry area.

143

BIO SKIN

DESIGNER: Nikken Sekkei Ltd. (Tomohiko Yamanashi, Tatsuyu Hatori, Yoshito Ishihara, Norihisa Kawashima)

SONY RESEARCH AND DEVELOPMENT OFFICE TOKYO, JAPAN

RESEARCH AND DEVELOPMENT: Nikken Sekkei Research Institute (NSRI), Katsumi Niwa CERAMIC MANUFACTURER: Toto Ltd. COMPLETION: 2011 CERAMIC ELEMENTS: Tile geometry: cross-section 70 × 110 mm, diameter 12 mm, typical length

70 mm

1,800 mm; 9,504 extruded pipe segments with

110 mm

wet-molded end caps

1.800 mm

1 – Typical ceramic element.

Tokyo, like many large urban conglomerations, has long experienced an urban heat island effect that has led to rising temperatures compared to less developed areas on the outskirts. Traditional solutions include the construction of green spaces, urban ventilation corridors, and white roofs on buildings. Evaporative cooling through an extremely large ceramic surface represents a novel approach. This facade system addresses both the increase in urban temperature as well as the desire to lower building energy consumption. The narrow building is designed to allow the prevailing winds from Tokyo bay to enter the city. The eastern facade features a system of water-filled ceramic pipes that double up as railing for exterior balconies—the BIO SKIN (1, 2, 3, 4). Its functionality depends entirely on the porosity of custom-extruded ceramic pipes that allow for controlled water evaporation on hot days—thereby producing a veil of cool air and reducing air temperatures in the vicinity of the building. The BIO SKIN system was inspired by the traditional Japanese use of sudare screens, horizontal bamboo or wood slats woven together with thin thread and used to protect outdoor veranda spaces from the sun. The current design recalls this reference, albeit at the scale of a tall building. The design team initially compared the cooling capacity of water-filled porous ceramic pipes with a horizontal aluminum

THERMODYNAMIC SKINS

louver system. Tests on a prototype at conditions similar to those at the actual site showed clear benefits of the ceramic solution with the wet ceramic system featuring a 5–9°C lower surface temperature. Computational fluid dynamics (CFD) simulations on the scale of the actual building predicted a 10°C lower surface temperature, a 1–2°C lower temperature near the glass enclosure behind, and a 2°C lower temperature in the immediate surroundings of the building. Measurements by Nikken’s engineers during operation of the finished building confirmed the thermal benefits of the ceramic facade, with a difference in surface temperature between BIO SKIN and non-shaded parts of the eastern facade of 11.6°C. Temperatures in the urban vicinity of the building were also measurably lower, but due to the newly planted trees it is difficult to quantify what portions of the heat reductions are due to the evaporative cooling effect of the facade. The system is operated by rainwater stored in underground tanks from where it is pumped through the pipes. Operational electricity is provided by photovoltaic panels installed on site. The horizontal pipes are mounted with stainless steel hardware to high-strength steel tension cables that are suspended vertically along the facade (5, 6, 7). The spacing of the pipes—denser in the railing area, less dense in the area above the vision zone—

also helps control solar heat gains by partially blocking direct sunlight. The ceramic pipes with an oval cross-section of 110 × 70 mm were extruded in 1.8 m long segments. The clay body was customized by adding a granular additive such that water permeability was approximately 10%. The disadvantage of high water absorption of the ceramic is the increased risk of moss and mold growth in Tokyo’s humid climate, but an appropriate vertical spacing of the pipes ensures good ventilation. A photocatalytic coating of titanium dioxide (Ti2) was added to further prevent the growth of plants on the pipes. To achieve the horizontal span between cable supports, each hollow pipe is supported by an internal aluminum profile. Both materials are joined by an elastic adhesive. A stainless steel piping system leads the water around the corners to connect adjacent horizontal ceramic elements. This corner piping is covered with molded ceramic cap pieces that match the color of the ceramic pipes. Over 9,500 pipes were installed in the building, shading the 140 × 120 m glazed east facade (8, 9). As an urban prototype the building successfully synthesizes local references with a conceptually simple but technically sophisticated approach to cooling a building’s boundary layer. The material design of the ceramic system is an integral aspect of this approach (10).

3 – Exterior view from the southeast.

2 – Site plan and section showing cooling effect.

4 – Typical floor plan.

145

110 mm

70 mm

7 – Facade section and element detail. The ceramic extrusions are adhered to an aluminum core.

5 – Facade close-up.

8 – Exploded system view.

6 – First mock-up.

THERMODYNAMIC SKINS

9 – Interior close-up.

10 – Partial exterior view.

147

CHAPTER 11

FORM CUSTOMIZATION STRATEGIES

The contemporary demand for the form customization of construction elements can generally be traced to two related, yet distinct, impetuses. The first is design-driven, the second aims to optimize building performance—combinations obviously exist as well. The performance-based approach seeks to optimize a particular performance characteristic (daylighting, ventilation, structural, etc.) through individualized strategic customization. Despite the different starting points of these two approaches, their outcomes may have similar repercussions for the design of facades, roofs, or other building parts. In these cases constituent ceramic elements often need to vary in shape, occur in many configurations and versions, and all but eliminate the notion of a standard part. This pursuit of formal variation has also contributed to the emergence of novel modes of design practice, and increasingly new players have been introduced to the industry that help bridge the gap between the design intent and the realities of building construction. The principles of mass-customization have often been quoted as the savior of architecture’s age-old pursuit of individualized solutions. It is all too easy to overlook that “mass” is typically missing in the context of project-specific architectural production. Here production volumes are a few thousand or ten thousand elements at best, still very small compared to high-volume mass production. Any varied production approach will struggle with the fundamental conundrum of reconciling cost and time, both of design—including engineering—and production. While the former can be effectively supported with the appropriate computational tools, the same seamlessness does not exist on the level of production. Here fixed costs for tooling (molds, forms, cutters, etc.) and set-up (e.g., installing and preparing tooling for production) have to be “financed” over larger production runs. Variable costs include materials, labor, machine depreciation, and other factors of production. Compared to most other raw materials, architectural ceramics come in a wider range of states, from dry clay powder to moist clay and highly liquid slip. The plasticity and viscosity of clay are key parameters that determine appropriate production methods, which in turn come with their own combinations of fixed costs and variable costs. Glazes and kiln firing strategies add further to the toolkit of ceramic designers with costs relative to production volumes. Ceramic production processes thus offer unique opportunities of multi-stage interventions towards customized outcomes. Clay body design, shaping methods, manipulations in the wet, green, and fired states are reviewed in Chapter 3, and these factors all contribute to creating a highly versatile and cost-effective material system that supports contemporary needs for form customization. Among the range of production processes for different clay consistencies, “wet processes” clearly emerge as the most promising for form customization (1, 2, 3). These involve relatively efficient extrusion or stamping techniques, combined with post-processing such as cutting, bending, slumping, adhering, and others. The production equipment involved is relatively simple.

1 – A series of custom slip-casting molds produced by Ceràmica Cumella.

2 – A custom curved extrusion at the shops of Ceràmica Cumella.

Tooling for extrusions can be produced with common tools found in any qualified metal fabrication shop, and stamping tools for plastic clay do not have to resist high pressures that would necessitate costly, high-strength materials. The industry has maintained a productive mix of craft-based and industrial methods particularly conducive for project-specific production volumes. Such settings often combine sophisticated, numerically controlled kilns used to fire elements produced in relatively basic ways on a variety of production lines involving little if any automation. Here simple machines may do the bulk of the work, but two or more experts may service each line and handle post-processing of base shapes in a highly flexible setting. Finally, ceramics can be further manipulated—subdivided, scored, trimmed, drilled—in the green state or once fired. The forces involved are higher after firing, thus requiring more substantial equipment, but with the added benefit of increased precision because the effects of shrinkage have been eliminated. The following case studies explore formal customization in producing architectural ceramic elements. In some, individualized ceramic components are created to form a one-of-a-kind envelope system that may include a project-specific substructure. In others, individual ceramic units within a standardized construction system of substructures and connectors are modified to accommodate specific architectural conditions. In cases where the form is derived digitally, tooling is often created using computer numerically controlled (CNC) equipment such as lasers or milling machines, while the actual forming of the ceramic material remains manual—at least at some level. Opportunities for formal customization with more substantial involvement of digitally controlled equipment are on the horizon and are included in the Chapter 12. 3 – A complex slip-cast ceramic element for use in the Sagrada Familia in Barcelona, Spain, shown here in the studio of Ceràmica Cumella.

149

COMPUTER-AIDED SLUMP MOLDING

DESIGNER: Enric Ruiz-Geli (Cloud 9) COMPLETED: 2009 CERAMIC MANUFACTURER: Ceràmica Cumella CERAMIC ELEMENTS: 460 slump-molded glazed stoneware elements 600 × 25 × (500–1,400) mm

VILLA NURBS EMPURIABRAVA, SPAIN

1 – Detail of ceramic panel hung from the cable structure.

Villa Nurbs has been described as a laboratory for mass-customization, testing the boundaries of customization in architecture through a variety of materials. Three separate living areas blend into a single structure surrounding a central swimming pool that rests atop a massive concrete base. The elevation of the building is stratified into three layers. First, a unique tripod-like arrangement of post-tensioned concrete columns constructed of topographic layers anchors the building to the ground. The second brings together the three living areas and is wrapped in a heterogenous facade, including the ceramic rain screen (2). The third is a group of six ETFE pillows that make the roof of the structure (7, 8). The stoneware rain screen—fabricated by Ceràmica Cumella—covers a large portion of the facade, is supported by a custom cable netting system and is buffered by an EPDM tube that surrounds the net where the ceramic elements are present (1). Unit variation allows the ceramic parts to conform to the complex shape of the building. These are applied based on the relative curvature of the facade (9). Each of the twelve types of ceramic elements exploits three opportunities for customization including perimeter shaping, three-dimensional form, and surface finish. The elements are created through a slump molding process. Due to the industrial nature of the element production and the relatively low water content of the base clay, very little variation is seen between similar units. After firing, each

FORM CUSTOMIZATION STRATEGIES

unit was custom-glazed—some by artist Frederic Amat—for a high level of individual customization (5). During production, a 600 × 25 mm extrusion was hand-cut to prescribed two-dimensional shapes using water-jet aluminum patterns and then manually slumped over individual expanded polystyrene molds (3, 4). The molds were translated from the architect-prepared digital model using a three-axis CNC milling machine. In total, 60 molds were created and reused to form parts in batches to achieve the final 460 elements that range in length from 500–1,400 mm. Each of the twelve shapes was coded on the edge so that installation instructions could be easily translated on site by way of color-coded facade drawings. The underlying process used to create the base slabs for slumping ensures a consistent part thickness that enables all pieces to behave similarly during forming and to be fired using the same kiln schedule (11). Material shrinkage resulted in a final part thickness of 22 mm, based on the experience and intuition of the ceramic manufacturer rather than prescribed by computational or rigorous performance calculations. Once finished, units were hand-packaged by the fabricator and delivered to the site for installation (6, 12). The flexibility of the ceramic manufacturer overcame any logistical barriers of shape customization including packaging and shipping, which are typically a bottleneck in the production of varied parts. Part replacement, a common concern when dealing with individualized parts, is accounted

for by the fabricator who holds one physical example of each mold type along with a catalog of shop drawings and digital files to ensure the long-term sustainability of the ceramic rain screen. For Villa Nurbs, strategic customization was employed to create three-dimensional ceramic elements. The detail system was more standardized and based on hooking the elements onto a geometrically regular cable grid. While restraint—in terms of digital customization—may seem out of place in the context of this project, the formal customization strategy allows for a relatively straightforward assembly logic based on grouping of self-similar elements while resisting the opportunity to make each unit formally unique. A customized secondary finish does enable total individualization within the system, thus realizing the full gamut of customization allowed in low-volume ceramic production in terms of form, finish, and installation strategy (10, 13). Villa Nurbs takes advantage of the area between industrial production and craftbased fabrication where the desire for customization results in the automated production of custom tooling (molds and patterns). The industrial nature of part production gives way to a very manual craft-based process at the intersection of the digitally fabricated tooling and the material itself. This confluence of the automated and the manual is common when dealing with form variation, and all shaping and forming for the Villa Nurbs elements was ultimately a manual operation.

4 – Extruded and trimmed element prior to slumping.

5 – Artist Frederic Amat individually glazing slumped ceramic elements.

2 – Villa Nurbs ceramic rain screen.

6 – Workers install ceramic elements onto structure on site.

3 – Individual ceramic elements slump-molded on polystyrene molds.

151

8 – Building roof elevation showing ETFE “bubbles”.

7 – Facade section showing the formal unit variation in aggregate.

9 – Selected of individual element types based on relative facade curvature.

FORM CUSTOMIZATION STRATEGIES

686

639

500

926

455

869

455

812

495

754

495

500

581

530

523

550

11 – Each element is supported during firing to reduce warping.

12 – Partially installed rain screen.

10 – Completed rain screen.

13 – Completed project including ceramic rain screen.

153

VOLUMETRIC PIXELIZATION

DESIGNER: Foreign Office Architects (FOA), Farshid Moussavi and Alejandro Zaera COMPLETED: 2005 CERAMIC MANUFACTURER: Ceràmica Cumella and Decorativa, Tozeto SA CERAMIC ELEMENTS: Plastic-pressed glazed

SPANISH PAVILION, EXPO 2005 AICHI, JAPAN

stoneware tiles 500 × 430 × 125 mm

1 – Elevation drawing of the aggregate facade assembly.

The Spanish Pavilion at the 2005 Exposition in Aichi, Japan, is characterized by its ceramic facade, a reinterpretation of the lattice screen, itself a symbol of the synthesis of Islamic and Judeo-Christian cultures that marks Spain’s unique history (1,2). The interior of the pavilion is comprised of small peripheral rooms surrounding a central gallery—an allusion to Gothic cathedrals and Muslim courtyard homes. The ceramic facade consists of six unique types of a hexagonal form, each joined with a symmetric pair to form an exterior and interior face (3). A seventh type, a corner unit, completes the system (5). The custom elements were produced by Ceràmica Cumella, a Spanish company specializing in custom ceramic manufacturing, through a method of plastic pressing in partnership with Decorativa. The process—described in Chapter 4—utilizes a pneumatic press

FORM CUSTOMIZATION STRATEGIES

to force semi-wet clay between a two-part mold (6). Secondary processes were used to form the open elements (4). Before firing, while the clay was in the green state, the bottom of the pressed unit was removed to produce the final form (7). After firing, slots were cut into the elements to accommodate assembly and installation detailing. Approximately 12,400 pieces were produced to create the facade. In this case, a relatively large volume of custom parts were created in series using custom tooling. Because plastic pressing involves lower pressures than dry pressing, molds can be created from materials such as wood or mild steel, which require less time to produce and therefore lower cost. A family of six custom molds was created to produce large groups of like elements. Secondary processing and later a variety of glaze colors were incorporated to resolve

detailing considerations not possible in the initial pressing operation, and ultimately the group of custom units was applied in an aggregated manner that diminishes the visual impact of the individual elements. The finished elements are 500 × 430 × 125 mm with a material thickness of 12 mm. Brackets, adhered to slots machined in the fired piece, join mechanically to a vertical steel substructure that unifies the two halves of the assembly (8, 9). The irregularity of the six types was combined with the palette of glazes to produce a homogenous yet constantly varying pattern. Vibrant glazes of red, ochre, and brown may evoke classic images of Spain, but underneath is an even more striking symbol—the ceramic elements—quite literally “Spanish soil” transplanted to Japan (10).

2 – The aggregation of multi-colored pressed ceramic element creates a dynamic “deep” surface.

217 mm

250 mm

375 mm

3 – Detail drawing of a representative element and its connection detail.

4 – Exterior facade showing variation in unit type and color.

155

5 – Completed exterior of the pavilion. 6 – Plastic pressing was used to create individual elements using a two-part mold. 7 – Pressed parts are trimmed to create openings. 8 – Two halves are assembled to form the double-sided surface. 9 – Individual finished element.

FORM CUSTOMIZATION STRATEGIES

10 – Completed interior view of the pavilion.

157

HIGH-RELIEF SLIP-CAST SURFACES

DESIGNER: Peter Lynch, Studio Metasus with Ahlaiya Yung COMPLETED: 2009 CERAMIC MANUFACTURER: Craft-based, team of local craftsmen CERAMIC ELEMENTS: Slip-cast porcelain tiles

VILLA FOR AN INDUSTRIALIST SHENZHEN, CHINA

E

Tile

Half tile

C

D

Quarter tile 80

73 75

Keyed hole for mortar attachment, typ.

70

A

45

E

D

R4 typ.

R23

C 71 75

B

R27

67

125 120

112 typ. Tile course dim.

B B

B

B 87

4 typ B

Full “plus” tile

146 150

A

Top view

End tile (flat)

Bottom view

1 – Drawing of an individual representative unit showing keyed opening developed to create a mechanical bond once the mortar has cured.

The design intention for this interior renovation of a 464 m2 villa in Shenzhen, China, was to implement new ideas about craft, geometry, and ornament. Each space within the villa is delineated through material-specific crafted elements, displaying the skills of the local craftsmen in materials such as aluminum, hardwood, porcelain, and woven rattan, with each programmatic space representing a separate craft. Customization was made possible by direct relationships between local craftspeople and the designers working closely with the fabricators during the project’s realization. For the space comprising the highrelief slip-cast ceramic wall tiles, groups of four geometric modules are nested to form the repeating element with various combinations of the base geometry (1,2). The modular unit was conceived through hand drawing and then translated to digital geometry (3) which was in turn modified and 3D-printed. The form of the printed pattern was calibrated by hand,

FORM CUSTOMIZATION STRATEGIES

then used to create a series of slip casting molds (4). Further customization occurred in the glazing of the units, and unexpected color variation occurred within each small-batch production run, common in the craft-based production setting of this project. Global aggregation of the unit was determined during installation, based on inconsistencies in glaze coloring. Glaze variation is common in most low-volume production scenarios and is especially prevalent in the craft-based production setting employed in this project. Installation of high-relief surfaces requires special care during grouting and in this case the grout was applied by hand (5). The production of the ceramic elements exemplifies what is possible through the engagement of the designer with the craftsman at the level of unit production, when labor is not the driving cost of production. The incorporation of the digital during this process—a 3D-printed pattern used for fabrication—positions this project

as an example of the conversation between the rigidly prescribed and the reality of the final construction (8, 9). Unlike most architectural products that operate within a standard range of tolerance, ceramic elements—particularly those produced in craft-based manufacturing environments—have the potential to exhibit a high degree of variation, even with parts from the same mold. A skilled ceramicist can maintain a high level of precision and consistency from part to part. During the slip casting process the composition and amount of slip, along with the amount of time the slip remains in the mold, all play a role in the final outcome. The longer the slip is exposed to the air the more likely it is to change consistency; the more times the plaster mold is used the less absorptive it becomes. In a high-volume production system these parameters are assumed and controlled, but in a craft-based environment the skill of the ceramicist becomes the metric for quality control (6, 7, 10).

R80

R40

R20 R20

R13

R20

5

5

5

5 typ

2 – Section drawing of an individual representative unit showing keyed opening developed to create a mechanical bond once the mortar has cured.

Glazed slip-cast ceramic tile

14

23 31

Section E-E through half tile

Keyed hole for mortar attachment, typ.

81

22

Section D-D through half tile Keyed hole for mortar attachment, typ.

3 – An individual prototype element made of plasticine.

4 – A prototypical positive was employed as a pattern to create slip casting molds used in the final production.

5 – High-relief tiles combined with a slightly curved substrate create a dynamic lighting effect in the basement of the villa.

159

6 – Overall panoramic view of the ceramic surfaces.

7 – Unrolled elevation of the modular pattern that was used to guide the installation of the bar elements.

8 – The installation was entirely manual, with positioning and spacing maintained by the installer without templates.

FORM CUSTOMIZATION STRATEGIES

9 – Image of in-process installation showing modular variations of the individual units.

10 – Completed installation creates a dramatic effect within the bar area.

161

LOW-VOLUME CUSTOM EXTRUSION KOSEMO BRICK, ARCHIE BRAY FOUNDATION HELENA, MONTANA, USA

DESIGNER: Nathan Craven COMPLETED: 2005 CERAMIC MANUFACTURER: Craft-based, Nathan Craven CERAMIC ELEMENTS: Manually extruded stoneware, assembled dimension 92 × 57 × 200 mm

1 – Installation diagram used to ensure correct patterning.

Nathan Craven is a ceramic artist whose work explores ceramics in the context of architecture through large-format installations and building applications. This project explores the possibilities of low-volume manual terra cotta extrusion. The Kosemo Brick, temporarily installed at the Archie Bray Foundation in Helena, Montana, is comprised of a series of interlocking extruded shapes (1). As seen in other cases, including the Zaragoza Pavilion (see Chapter 10), extrusion allows the creation of custom components with a continuous cross-section. For industrial production, the requisite custom die costs between USD 2,000–10,000, requiring a large production volume to be economical. The Kosemo Brick—using manual extru-

FORM CUSTOMIZATION STRATEGIES

sion—has relatively low tooling costs for an architectural facade installation of 2,390 × 2,590 × 140 mm (2, 3, 4). Four complex interlocking extrusions form a single rectangular unit or “brick” (10, 11). During production, a clay “slug’” is extruded, dried, and bisque-fired. The fired slug is then cut into shorter units of a finished dimension, using a wet saw, and these units are individually glazed (5). Typical of most extruded ceramic elements, the Kosemo Brick has a hollow cross-section, but unlike many screen-like architectural applications these units are combined with a secondary material, glass, to create a weather barrier. The enclosed block is created during an additional firing when glass frit is partially kiln-cast into

the hollow extruded section. During firing, the glass becomes molten and bonds to the ceramic material and—because of careful considerations in kiln programming and material composition to ensure compatible coefficient of expansion—the element behaves as a single hybrid unit. This installation demonstrates the opportunities for customization at very low production volumes through craft-based means. Manual extrusion adheres to similar process parameters as industrial-based extrusion, and this project could conceivably be scaled to a larger application (6). The strategic use of custom ceramic elements results in an architectural condition beyond what would be possible with more common shading screens (6, 7, 8, 9).

2 – The aggregate units.

3 – Extrusion dies are created from common materials using accessible tooling. 4 – Final die fabrication.

5 – Once fired, extruded elements are cut to length using a wet saw. 6 – In-process installation.

163

7 – The installed wall.

8 – Exterior view of the installation, showing the visual lighting effect of the cast frit within the extruded units.

FORM CUSTOMIZATION STRATEGIES

9 – Material effect of the assembled wall.

10 – Drawing showing interlocking individual elements that form the building module.

11 – Assembled wall detail.

165

SYSTEMIC VARIATION

DESIGNER: Sauerbruch Hutton COMPLETED: 2013 CERAMIC MANUFACTURER: NBK Architectural

MINISTRY OF URBAN DEVELOPMENT AND ENVIRONMENT HAMBURG, GERMANY

1 – Plan drawing of the Ministry of Urban Development and Environment.

Form customization through extrusion can be seen in this project by Berlin-based architects Sauerbruch Hutton (1). The facade consists of 27,000 ceramic units that exemplify form and color customization within medium- to high-volume production (2,3). The extrusion process, when combined with die customization, enables a range of project-specific cross-sections. Extruded facade systems are available in pre-defined shapes but often—as with all NBK systems—a custom die is produced for each project. Custom dies have an approximate six week lead-time until the first tiles are extruded. Dies are scaled to compensate for clay shrinkage, a function of the clay body composition, so all project parameters must be defined prior to tooling. During the extrusion process, clay is forced through the die by large helical extruders onto a proprietary conveyor that protects the underside of the unit to ensure consistency (see Chapter 4 for details). Beyond the primary extrusion process, secondary forming processes enable individual ceramic elements to respond to specific architectural conditions, including corners and both concave- and convex-curved building geometry (8, 13, 14). From the extrusion line, specialty parts

FORM CUSTOMIZATION STRATEGIES

Terracotta CERAMIC ELEMENTS: Extruded terra cotta in various lengths, finished in a range of colors

2 – Aerial view.

are transferred to a secondary production line where they are molded by hand into one-sided plaster molds. Parts are molded with the finish surface against the mold face so that any curvature-induced material deformation can be corrected by hand without impacting the visible face of the unit. While secondary forming processes maintain the tolerance of the universal assembly system, some variation is expected. Because the secondary manual processes add significant cost to the unit, curved parts are specified only for highly visible areas where the building’s curvature exceeds what can be resolved through flat parts. All elements are cut to final length prior to glazing—typically when in bisque state—using a CNC wet saw to refine tolerance post-shrinkage (4). After parts are dimensionally rectified, a glaze is applied using an industrial robotic work cell. To ensure consistency and homogeneity in appearance, glaze is applied to all faces of the parts—including the ends, which are often left unfinished. Each element is hollow with dual 10 mm layers and a corresponding 10 mm air space between. Integral struts are spaced periodically and span between the two layers. The hollow section minimizes weight while adding structural depth, provides

spaces for reinforcement bars as needed, and allows enough space to incorporate mechanical installation detailing without reducing unit performance. Each element is individually self-supporting and can be replaced without disrupting the global system (9). The extruded elements are designed to fit within a family of details, and all facades produced by NBK incorporate installation considerations that match prescribed standardized systems (11). In this case, a hidden channel is included in the extrusion so that the element can engage a group of cleats attached to the substructure on the building (12). Each element overlaps the part below, thus keeping the cleats out of sight on the finished surface. In some cases, particularly where a part spans an opening or a seam occurs in an unsupported condition, an aluminum extrusion is used to reinforce the part’s hollow section (10). The facade system consists of 2,044 prefabricated units that include enclosure, windows, and finish mounting hardware shipped to the site. Typically the ceramic elements are installed on the prefabricated facade components prior to building installation (5, 6, 7).

3 – The completed facade enables the building to blend into its surroundings.

4 – A wet saw is used to cut the extruded elements to final length prior to glazing. 5 – Ceramic elements are staged on site prior to assembly. 6 – Prefabricated facade units are lifted into place.

7 – Facade assemblies are installed onto the building with minimal labor.

167

8 – Detail of completed facade showing periodic curvature.

9 – Facade detail utilizes a hidden connection while allowing individual elements to be removed without disturbing the neighboring units.

10 – Integrated reinforcement allows ceramic elements to span voids in the facade.

FORM CUSTOMIZATION STRATEGIES

11 – Integrated channels engage standardized mounting hardware.

12 – Detail section drawing showing variation within the family of extrusions.

13 – Continuously curving horizontal ceramic elements conform to the dynamic façade.

14 – Detail of curved facade elements.

169

DIGITAL RECONSTRUCTION ALBERTA LEGISLATURE BUILDING DOME RECONSTRUCTION EDMONTON, ALBERTA, CANADA

DESIGNER: Allan Merrick Jeffers (original building) CERAMIC AND FACADE CONSULTANT: Building Science Engineering Ltd. COMPLETED: 2014 CERAMIC MANUFACTURER: Gibbs & Canning (original building); Boston Valley Terra Cotta (replacement) CERAMIC ELEMENTS: Extruded, cast, and hand carved terra cotta. A typical ridge element measures 600 × 305 × 535 mm. Ashlar units are 50 or 150 mm deep at 305 mm height.

1 – 3D scanned data was used to produce computational models of each complex element.

Terra cotta cladding was commonly used in the late 1800’s through the early 20 th century. Today, these facades have been exposed to the elements for over 100 years and many are in desperate need of restoration—often requiring replacement. Until recently, this process was similar to the original analog design-to-production model that started with the architect’s 2D drawings, shop drawings scaled to accommodate shrinkage, the production of plaster models, and then molds for making the reproduction units. The restoration of the Alberta Legislature Building dome shows that a digital design workflow can now facilitate and accelerate this tried and true process (1,2). The 1912 building features two domes clad with terra cotta produced to match the appearance of the sandstone of the upper floors. The larger of the two domes reaches a height of 54 m, thus presenting a challenge for construction and the need for extensive scaffolding and staging (6). The dome’s terra cotta facade had undergone an initial restoration in 1987 when bowing of the cladding elements away from the steel structures was addressed. To prevent further displacement, steel anchors were embedded and epoxied into the back of the terra cotta elements, tying these elements to the underlying structural steel. Additional improvements included waterproofing, and the combined effort stabilized the existing surface cladding for

FORM CUSTOMIZATION STRATEGIES

two decades. In 2012 the owner launched a more substantial renovation to replace the original terra cotta elements with replicas, renewing the structural surface of the larger of the two domes, improving waterproofing and installing new terra cotta units with a ventilated air space to ensure durability (7). Boston Valley Terra Cotta (BVTC), one of two remaining producers of terra cotta facade elements in North America, was commissioned to reproduce the over 18,000 cladding elements. The new dome roof included a 135 mm thick shotcrete surface supported by curved structural steel. Stainless steel anchors were embedded for the mounting of the new terra cotta rain screen, and 38 mm of sprayed-on insulation and waterproofing completed the surface preparation of the dome. One type of custom steel anchor supports the dead weight of the cladding, the other one maintains the proper spacing between the terra cotta and the underlying structural surface. A pattern of movement joints allow differential displacement of cladding and structures to take place without damage. 3D laser scans of one-eighth of the large dome produced the existing overall geometry, as well as surface data for each piece. Each element was modeled using Rhino incorporating the new base surface and the system of anchors. A 10 mm joint between pieces ensured a good fit of the complex assembly. All digital part files

were virtually assembled in an overall digital model of the dome. After scaling to accommodate for 8% clay shrinkage, the surface data could be used to produce toolpaths for a CNC milling machine used to create molds and patterns (3). Only highly ornamental pieces were carved by hand— similar to production in 1912 England (4). The clay composition was customized to provide excellent freeze-thaw resistance suitable for Edmonton’s harsh climate. BVTC staged a full-scale assembly mock-up over a wood substructure at their facility to test fit, color range, and tolerances (8). Color conformance with the dome’s original sandstone base was a key objective of the project. Assembly was based on detailed setting drawings that included reference points and part location, based on the as-built survey of the newly constructed structural surface. The Alberta dome reconstruction demonstrates the opportunities for digital workflows in support of the often challenging historic preservation of terra cotta architecture. Parts of the process can be digitized, while a sizeable portion—including the actual production of parts from molds—remains craft-based. Preserving cultural heritage might create deeper bonds with the past, but it does not preclude the use of innovative processes as enablers of success (5).

3 – A 5-axis CNC machining was used to create plugs from digital geometry.

2 – Alberta Legislature Building following the completed renovation.

4 – Highly decorative elements were made by hand using molds created using computational technologies.

6 – Major dome under renovation.

7 – Installation of replacement terra cotta details providing an air gap and additional structural support.

5 – Completed dome renovation.

171

ANGULAR VARIATION

DESIGNER: Barkow Leibinger Architects COMPLETED: 2008 CERAMIC MANUFACTURER: NBK Architectural

TRUMPF INDUSTRIAL CAMPUS RESTAURANT DITZINGEN, GERMANY

Terracotta CERAMIC ELEMENTS: Plastic pressed terra cotta, measuring 350 mm across with 15–45 mm in depth

2 – Detail elevation indicating the placement of the two element types.

3 – Detail photograph of factory-based prototype showing the aggregation of convex and concave elements.

1 – Detail drawing of the two element types.

The pavilion on the Trumpf industrial campus serves as a 700-person cafeteria and 800-seat auditorium in landmark opposition to the architectural typology of the surrounding industrial buildings. A “floating” roof that spans the open floor plan characterizes the building. The roof combines a steel frame with infill, constructed from individualized glue-laminated timbers. Each of the over 300 unique joints within the honeycomb-like roof structure is customized through CNC milling and cutting. The building is wrapped by what constitutes primarily a glass facade, with closed areas clad in custom ceramic elements (4). On the interior, the wall separating the main hall from the kitchen area is clad in the same high-relief elements used on the facade but differentiated by glaze colors that are also repeated periodically throughout the building. Two custom ceramic shapes, one convex and one concave, form a three-di-

FORM CUSTOMIZATION STRATEGIES

mensional surface pattern whose visual complexity is heightened through the strategic use of color (1, 2). Each unit is formed through plastic pressing (7, 8) and visual differentiation is achieved through variation in glaze coloring (3, 9). Each module fits within a bounding limit of 350 mm square and ranges in depth from 15–45 mm, creating a high-relief surface. In total, 12,000 units were created—5,000 on the exterior and 7,000 on the interior (5). The exterior pieces perform as a rain screen while the interior units are directly adhered to the substrate (6). The ceramic elements are characterized by angular facets that react to light in a variety of ways, creating a dynamic surface not typically associated with ceramic cladding (10, 11). The intersection of each facet is softened to reduce stresses associated with sharp angles, and additional details—such as the continuous reveal molded into each part to accumulate glaze overrun—were

developed in close collaboration with the ceramic manufacturer. The installation of the exterior elements utilized a series of aluminum details adhered to the back of the element and fastened to the substrate with screws, creating a dry installation process. On the interior, the elements are adhered to a substrate and joints are grouted to seal the surface. The use of custom ceramic elements added textural variety to an interior composed primarily of large planar surfaces (5). The specification of the ceramic elements in certain locations helps identify areas of programmatic importance and mimics the overall logic of the complex honeycomb roof system, which delineates programmatic function through module distribution. For this customization strategy, the versatility of the material was used to create integral modules that added visual and textural complexity to otherwise planar interior walls and exterior facades.

4 – Exterior view of the campus restaurant.

173

5 – Interior view of the cafeteria showing ceramic clad wall and honeycomb structural system.

6 – Installation in progress.

FORM CUSTOMIZATION STRATEGIES

7 – A clay billet is prepared for a pressing operation. 8 – Individual units are formed using a two-sided mold.

9 – Strategic use of colored glazes delineates programmatic shifts within the building.

10 – Elevation drawing of ceramic rain screen.

11 – Extended surface depth is created through the modulation of concave and convex elements.

175

DELINEATED PARALLAX

DESIGNER: Pol Femenias COMPLETED: 2013 CERAMIC MANUFACTURER: Ceràmica Cumella CERAMIC ELEMENTS: 14,256 extruded and glazed stoneware elements up to 200 × 200 × 200 mm

LA RIERA DE LA SALUT REMODEL SANT FELIU DE LLOBREGAT, SPAIN

0

m

m

20 m

20

0

m

20 20

134 mm

90,00°

45,00° 135,00°

134 mm

20 0

m

m

45,00° 135,00°

20 0

m

m

1 – Elevation drawing of the three individual ceramic elements.

2 – Drawing of unit aggregation.

Located in a working-class neighborhood— one of the most built-up areas of Sant Feliu de Llobregat—a wall divides a park from the private courtyards of houses erected around a now demolished textile factory (3). Ceramic was used to reflect the industrial heritage while allowing customization of the wall height, permeability, and color, as well as ensuring durability. An attempt was made to develop a simple geometric pattern using the fewest number of pieces that could address the various heights of the cross walls and changing topography along the 150 m length. Three pieces were developed for the latticework wall: a 200 × 200 × 200 mm

cube, a hollow rhomboid, and a solid rhomboid (1). The elements were extruded with 20 mm wall thicknesses and wire-cut (4). They were glazed in eight colors, each with the option of matte or gloss finishes for a total of 16 surface variations. To vary the permeability, the cube elements were rotated to appear open or closed (2). The rhomboids are identical forms that have been installed in different orientations to allow permeability and variation. A total of 4,752 square elements (2,671 placed as solid, facing front, and 2,081 placed as open), 5,243 solid rhomboids, and 4,261 open rhomboids were produced by Ceràmica Cumella, comprising the 420 m2 wall.

FORM CUSTOMIZATION STRATEGIES

They were produced in a single firing but at a higher than normal temperature of 1,240°C to ensure a high-quality product (5). The assembled elements are largely self-supporting, with only the addition of 4 mm steel rods that run internally to tie them together (6). With colors selected from its surroundings, the work blends naturally into its setting (7, 8, 9, 10, 11, 12). The design leverages two forms, three extrusion dies, and eight colors to create a piece that appears highly complex and customized.

3 – Aerial view of the ceramic wall that separates the private courtyards from the public space.

4 – Continuous formed profiles are cut to length immediately following extrusion. 5 – Collection of ceramic elements awaiting firing in the factory of Ceràmica Cumella.

6 – The installation sequence involves the periodic addition of reinforcement.

7 – Representative section of the aggregated assembly.

177

8 – Height variation in the wall mimics the neighboring skyline.

9 – Variation in orientation creates additional visual complexity.

FORM CUSTOMIZATION STRATEGIES

10 – Color variation enhances the complexity of the system without additional form customization.

11 – The 150 m wall continually follows the pathway.

12 – The ceramic wall separates the public from the private while blending with the surrounding architecture.

179

AGGREGATE PRODUCTION PROCESSES

DESIGNER: Campos Costa Arquitectos COMPLETED: 2012 CERAMIC MANUFACTURER: Ceràmica Cumella CERAMIC ELEMENTS: Extruded, plasticpressed, and die-cut stoneware elements

OCEANÁRIO ADDITION LISBON, PORTUGAL

1 – Drawing of the south elevation of the addition.

Sometimes multiple customization processes are required to create a system that may appear standardized. The original Aquarium was designed and built in 1998 by Peter Chermayeff, the addition was commissioned in 2008 and completed in 2012. The building is an irregular prism lifted off the ground on seven pylons and clad in over 5,000 custom ceramic elements (1, 2). The facade system presents itself as a repeating pattern of scallops, evoking images of fish scales or rippling water— associated with the Oceanário—while also referencing Lisbon’s long history of ceramic-clad buildings. The second level gradually transitions from a ventilated facade into an open shading element inspired by the Islamic screens of North Africa. Both systems help regulate the building climate—a major issue with its large southern exposure and the hot climate. The architects worked closely with the manufacturer Ceràmica Cumella to develop the ventilated facade elements, corner elements, open screen elements, and opaque

FORM CUSTOMIZATION STRATEGIES

screen elements, each requiring a different form and assembly logic. A majority of the facade elements are extruded, cut with a custom die into the scallop shape, and then press-molded into the final form (3, 4). To reduce costs, Campos Costa and Ceràmica Cumella cooperated closely to design an element that could use standard ventilated facade hanging systems (10). Open screen elements were extruded and slumped into the final curved form. Screws connect each element to an internal steel support structure (11). The connection allows the elements to shift due to the different rates of thermal expansion of the ceramic and steel, which otherwise—in the hot climate—would have caused the ceramic to crack. The opaque elements of the screen, which visually transition between the two systems and dapple the interior light, are in fact two custom forms (8). They are also extruded, die-cut, and pressed. The openings for the attachment system were then cut by hand using custom jigs.

Finally, the relatively few corner elements were pressed and post-processed by hand (5, 6). Glaze was airbrushed onto the complex forms. Firing and glaze production are so controlled and homogenized today that ten different shades of white glaze were chosen to intentionally create the variation in the facade color (7). As a result, depending on the time of day and quality of light (9, 12, 13) the building appears to ripple in subtle shades of green and yellow (14). Due to cost restrains, original ideas for structural ceramic elements were replaced with the ventilated facade and screen system through a long prototyping process with Ceràmica Cumella. Campos Costa notes that the firm’s goal is to have a closer relationship with industry in order to recapture a time when architects worked with manufacturers to develop more bespoke components. They admit it is hard to find industries willing to work in such a collaborative way but were pleased with the result in ceramics.

208

50

2 – Interior view through the facade.

416

50

19

195

257

50

64 516

8 – Drawing of the two primary facade elements. 3 – Clay is extruded and die-cut prior to forming. 4 – Individual clay element following pressing. 5 – Corner elements are composed of two elements that are joined by hand in the factory.

6 – Specialized elements remain on a supporting mold during the drying process to ensure consistency. 7 – Tonal modification in glaze coloring mimics craft-based variation that has largely been engineered out of most industrial production environments.

181

39

9 – The completed addition appears as a single homogenous architectural volume.

10 – Prototype of the standardized installation hardware.

FORM CUSTOMIZATION STRATEGIES

11 – Section drawing of the typical facade assembly.

12 – Oceanário Addition.

13 – Manually produced corner details allow continuity between the addition elevations.

14 – Tonal variation within the facade changes due to light conditions.

183

COMPOUND SURFACE DISCRETIZATION

DESIGNER: Bierman Henket Architects COMPLETED: 2013 CERAMIC MANUFACTURER: Royal Tichelaar Makkum CERAMIC ELEMENTS: Plastic pressed terra cotta, 100 and 200 mm square, with variegated glaze

MUSEUM DE FUNDATIE EXTENSION ZWOLLE, OVERIJSSEL, THE NETHERLANDS

1 – Elevation drawing of a representative aggregation of modular elements.

The 1841 courthouse became the home to the Provincial Planning Authority in 1977, which occupied the palace until the early 1990s. At that time a new cultural mission was given to the palace and in 2005 the architect Gunnar Daan planned the museum conversion and initial renovation. The recently completed renovation and expansion was opened in 2013 and is designed to accommodate larger exhibitions and increased museum traffic. The project features a large elliptical “cloud” that emerges from the neo-classical structure. It houses two exhibition spaces and provides an unprecedented view of the city through a large window cut in the otherwise homogenous construction (3). The exterior of the cloud structure is clad in 55,000 pressed terra cotta elements manufactured by the historic ceramic manufacturer Royal Tichelaar Makkum. Each element is glazed in a bluewhite gradient to visually blend with the

FORM CUSTOMIZATION STRATEGIES

2 – Ceramic elements are installed over a weather barrier.

sky and create a subtly changing surface. Each of the square elements is symmetrical in only one direction with a “high” side and a “low” side, which results in differentiation through 90° rotation (1, 2). The cloud’s 1,340 m2 elliptical surface is randomly patterned with two square units (20 and 10 cm). Due to the specific geometry of the addition, parallel horizontal bands are not possible and any geometric variation was taken up by shifting the spacing of each unit. Surface division began at the horizontal meridian, which was used to define four converging quadrants that are further divided into six horizontal bands (4, 5). Each quadrant is divided vertically into nine equal sections along the meridian. This geometric division allows for relatively consistent distribution of ceramic elements, based on fields filled at random by installers on site using a series of “rules of thumb” for location (7). Starting with the perimeter of each identified

field, installers were instructed to work toward the middle by placing a random combination of small and large elements rotated relative to each other at a spacing of roughly 5–10 mm (8). The combination of modularity and asymmetry enabled two custom elements to create a varied three-dimensional surface that—due to the random nature of the installation process—is likely to have no repeating fields. Regularity in the base geometry, combined with uniform installation logic, enabled the designers to clad the complex geometric surface without specifying the location of each individual unit. The use of ceramics allowed the designers to realize the intended blending with the sky by enabling both formal and finish customization. The resulting appearance visually ties the seemingly out-ofplace geometry to the surrounding roofline while blending smoothly to the point of disappearing against the sky (6, 9, 10).

3 – View of the front of the museum from the neighboring shops.

4– Front elevation of the building showing the glass aperture.

5 – Section drawing showing the relationship of the addition and the historic sections of the museum.

185

6 – View of the museum from across the canal.

7 – Installation is completed based on relative positioning and parameters that ensure natural variation in the system.

8 – Slight variation in spacing allows the orthogonal elements to follow the curvature of the addition.

FORM CUSTOMIZATION STRATEGIES

9 – Aerial view nearing completion.

10 – Gradient glazing allows the addition to blend with the sky while enabling the historic building to maintain its presence.

187

CHAPTER 12

EMERGING SYSTEMS

Research and design explorations in the area of ceramic systems are constantly evolving. While the primary innovation space of the ceramics industry surrounds the development of new glaze and finish technologies, design professionals, including architects, product designers, interior designers, and artists, are actively pursuing new ideas through the development of novel forms and methods. In addition, academic research has conceptualized new potential for application and innovation within ceramic systems, with a number of groups engaged in research activities. Newly emerging methods of assembly, unit aggregation, and digital fabrication are challenging the dominance of the ubiquitous ceramic tile. Ceramic materials have the potential to produce a great diversity of shapes through a variety of material processes that take advantage of a range of material properties. Craft-based manufacturing and high-volume production of ceramics are both affected by digital and robotic fabrication techniques and have emerged as a vehicle to test ideas related to computational design and material realization (1). Recognizing the potential offered by re-envisioning ceramic materials and processes in light of emerging design and manufacturing technologies, the ceramics industry has extended modes of collaboration with academic researchers and technologists. Industry collaborations with academic research organizations have led to the introduction of a variety of new ideas in the conversation surrounding the future of claybased ceramics and their application in architecture, culminating in ongoing course work that explores the intersection of emerging technologies and ceramic material systems. The well-established connection of many in the ceramics industry with leading research and design institutions worldwide suggests that the future of applications of ceramics in architecture and design is bright. As these collaborations yield commercially viable innovations, new design opportunities will emerge.

1 – Custom-automated processes offer new potential for design exploration.

This chapter introduces a selection of current projects and studies at the cusp of feasibility. It is intended to allude to application potential, along with viable research trajectories, for design teams that want to be among the first to experiment with new technology and system applications in buildings. In many of the cases presented here development is still ongoing, but the system at hand has reached a state of maturity that warrants the realistic prediction that a full-scale implementation is at least technically feasible. In many cases concepts of low-volume customization are revisited in light of an emerging technology, and in all examples new design ideas, intentions, and expressions are explored through emerging techniques, processes, and materials that rely on a deep understanding of collective knowledge that has evolved over centuries of human-material interaction, all within the realm of ceramic materials systems.

189

ROBOTIC TILE MOSAICS DESIGN ROBOTICS GROUP AT HARVARD UNIVERSITY GRADUATE SCHOOL OF DESIGN

RESEARCHERS: M. Bechthold, N. King, P. Michalatos, A. Kane, and A. Lee STATUS: Research, ongoing SPONSOR: ASCER Tile of Spain

1 – Screen capture of the Rhino-based integrated design-to-production workflow.

The manual installation of complex tile mosaics is hardly economical in industrialized economies. This project develops an integrated design-to-production workflow that allows a robotic work cell to efficiently place tiles robotically such that recognizable patterns are generated (1). The work differs from commercial approaches introduced earlier (see Chapter 9) in that it permits the use of tiles of varying sizes as determined by the user. The mosaic image is produced based on grout and tile having different tones or brightness. Assuming

EMERGING SYSTEMS

darker grout, a closer spacing of grout lines through the use of smaller tiles will create an overall darker tone in the eye of the observer (4). The software component allows users to upload images, which are then discretized based on tonal values and the available tile sizes that can be specified by the user. The graphical user interface allows for the image to be verified and easily permits edits and changes. Once the designers are satisfied, the same software is used to generate the actual code that runs a six-axis

robotic manipulator (5). Assuming an offsite robotic tile placement, the research includes the subdivision of larger tile surfaces into panels that can be tiled off-site and then installed manually on-site (2). Grouting takes place once all pre-tiled panels are installed such that an overall homogenous mosaic image is represented through the tile pattern (3). Extensions of the work include the use of multiple color tiles, real-time stochastic patterning, and the tiling of curved and complex surfaces with irregular boundaries.

2 – Displacement analysis of factory-installed mosaic panel ensures that each module remains intact during installation on site.

4 – Detail of tiled surface showing modular variation that allows change in grout line density.

5 – Robotic tile placement using a pneumatic suction gripper.

3 – Prototypical robotically constructed mosaic.

191

INTEGRATED ENVIRONMENTAL DESIGN-TO-ROBOTIC PRODUCTION

RESEACHERS: M. Bechthold, N.King, A. Kane, J. Lavallee, and others STATUS: Research, ongoing SPONSOR: ASCER Tile of Spain SUPPORTED BY: Ceramics Program, Office for the Arts at Harvard

DESIGN ROBOTICS GROUP AT HARVARD UNIVERSITY GRADUATE SCHOOL OF DESIGN Fabrication

Design Form Optimization Process

Tool Parameters

Output

Shading Design and Form-Finding

Grasshopper - Location - Desired Shading - Minimal Width

Optimal Shading Surfaces

Validation Through DIVA Software

File Pre p a ra tio n

Design Detailing Subdivision and Thickening

Grasshopper - Length - Thickness -Attachment Method

Orientation and Placement

Robotically Actuated Mold Setting

Rhinoscript

Pin Mold Rhinoscript

- Scaling - Location - Rotation

Individual Components

Pro d u c t i o n

Optimal Placement

- Mold Dimensions - Pin Height

Robot Movement Custom Mold

Post-Processing Material Deposition

Rectification

Extrusion Nozzle Grasshopper Script

Milling Head Grasshopper Script

- Vertical Offset - Stepover

- Vertical Offset - Stepover

Robot Movement Printed Component

Robot Movement Milled Component

Design Feedback Fabrication Feedback

1 – Environmental design-to-robotic production workflow.

Design teams have long been challenged by the complex requirements involved in the design and construction of building envelopes. This study presents an integrated design-to-production approach that involves a design environment for a system of external shading lamellas that can be optimized to minimize energy consumption while maintaining desired views and expressive patterns. Emphasis is on the ability to mass-customize the actual lamellas, assuming architects will pursue highly individualized designs and patterns. Facades with different orientations relative to the sun, combined with possible inclinations, will also require highly individualized shading patterns (1). Within the same software, the lamella can be prepared for robotic production

EMERGING SYSTEMS

by adding thickness and segment length based on structural and construction requirements. The robotic production environment is a modular system comprised of a variable mold that shapes a ceramic extrusion. The researchers developed a dedicated robotic 3D ceramic placement system that deposits wet clay over the mold surface. If used in typical industrial production settings, the latter step can be substituted by draping flat extruded or hollow extruded elements immediately after the extrusion process, thus in their wet and flexible state, over the variable mold. The prototypical mold involves a series of height-adjustable robotically positioned pins. An interpolating surface is used to provide a continuous surface area (2). The proprietary mechanism locks all pins

in place such that the resulting pin surface can support the weight of the wet clay body. In typical industrial systems, a flat extruded (solid or hollow) element would be placed and shaped over the mold such that the desired shading lamella form can be created. The relative stiffness of the wet clay further aids in smoothly interpolating between pin positions such that no indentations from the pins are visible in the final product. In a more advanced system, a wet clay mix can be extruded directly over the mold such that custom lamellas are produced (3). The ability to eliminate a cost penalty for the production of serially varying elements opens up an entirely new territory for ceramic facade systems (4). The production of other ceramic elements is equally feasible.

2 – Robotically actuated variable mold surface is positioned for individualized lamella production.

3 – In the prototyped process, automated robotic material extrusion is used to produce each individualized ceramic element.

4 – Full-scale prototypical facade section showing a series of individualized ceramic elements.

193

THERMALLY ACTIVE BUILDING ENVELOPE THE CENTER FOR ARCHITECTURE, SCIENCE AND ECOLOGY, RENSSELAER POLYTECHNIC INSTITUTE AND SKIDMORE, OWINGS & MERRILL (SOM)

DESIGNERS: Jason Oliver Vollen RA, Associate Director and Kelly Winn STATUS: Research, ongoing SUPPORT PROVIDED BY: AIA Upjohn Research Grant, Nexus-NY, Dr. Shay Harrison and Tegula Tile

1 – Rendering of representative unit including thermally active surface and integrated cooling loop.

Researchers at the Center for Architecture, Science and Ecology are working on the prototypical design of a ceramic envelope system that takes advantage of the relative ease with which custom ceramic elements can be designed and produced. The ongoing work studies the interaction between a variety of effects that have traditionally been utilized as isolated phenomena in separate building elements. Research of the so-called High-performance Masonry System (HpMS) has developed a component that allows the facade to be self-shaded through the combination of its overall form and smaller surface dimples (1). Simulation studies have shown that a dimple surface pattern can be used to increase the overall solar gain on a collecting surface by increasing the range of angles where direct solar insulation is received (3). The small-scale testing has established that a dimple pattern can be combined effectively with coloration in order to de-

EMERGING SYSTEMS

crease summer heat gain by self-shading and increase winter heat gain by a dark color pattern on a vertical surface. The overall shaping of the ceramic is geared towards maximizing self-shading while maintaining large solar collection values at the top surface. The geometry is to be adjusted to a specific location (4). The prototype shown is designed to work best in continental, colder climates. For use in arid climates with significant diurnal temperature fluctuations, the actual thermal mass of the envelope system can be enhanced by integrating Phase Change Materials (PCM) that store large amounts of latent heat (2). If designed correctly for specific climates they can contribute to delaying temperature increases during the day by allowing for the solar energy to be stored in the PCMs. An integrated liquid cooling loop can be used to transfer this heat energy to a heat exchanger for nighttime cooling or collection.

2 – Prototypical cast facade elements.

3 – In-situ rendering of thermally active building envelope.

4 – Detail rendering of thermally active building envelope.

195

STRUCTURAL CERAMIC SHELL

DESIGNERS: M. Bechthold, F. Raspall, Q. Su, M. Imbern, S. Andreani, A. Lee, K. Hinz, and others (Harvard GSD); A. Trummer (TU Graz) STATUS: Research, ongoing SPONSOR: ASCER Tile of Spain

MATERIAL PROCESSES AND SYSTEMS GROUP AT HARVARD UNIVERSITY, GRAZ UNIVERSITY OF TECHNOLOGY

1 – Computational structural analysis of the prototypical shell structure.

The structural use of ceramics flourished in the work of Rafael Guastavino and Eladio Dieste, but few if any new developments have occurred since that time. Researchers at Harvard University and Graz University of Technology have now developed a strategy for using three-dimensionally formed ceramic elements in composite action with ultra-high-strength fiber concrete (UHSFC) for the construction of rigid shell structures (1). The ceramic elements are designed to produce the formwork for two perpendicularly oriented concrete ribs. Once the ribs are cast using UHSFC, all ceramic elements are connected into a rigid surface structure consisting of extremely stiff, thin concrete ribs and their ceramic

EMERGING SYSTEMS

2 – Rendering of the proposed proof of concept used to develop the initial prototype.

surface elements, which stabilize the ribs, prevent grid distortion, and form an enclosed surface that sheds water (2). The size of the ceramic is determined by production constraints of plastic-pressing or slip casting, both processes with low tooling costs suitable for small production volumes in the hundreds of parts (4). The choice of fabrication method depends largely on the available fabrication expertise and equipment. Custom elements can be developed to form a broad range of overall shell shapes based on a few guiding principles. The team developed a specific ceramic element that forms a variety of non-developable larger surfaces similar to hyperbolic paraboloids, albeit with only

a single ruling line. The UHSFC is cast into the hollow channels formed by the array of ceramic elements (5). Gaps between the elements can accommodate fabrication tolerances as well as subtle differences between the pure mathematical addition of the elements and the global surface geometry. The gaps are sealed either by a system-compliant elastomeric gasket or by casting the UHSFC inside flexible liner tubes that conform to the channel shape. Metal corner connectors tie the perpendicular concrete channels and the ceramic surface elements together and provide shear resistance. The concrete/ceramic hybrid system can be used to produce a broad range of exciting structural shapes (3).

3 – Aggregated ceramic elements on display at the 2014 CEVISAMA exhibition in Valencia, Spain.

5 – Installation of the completed prototypical assembly.

4 – Prototypical ceramic element produced using a slip-casting process.

197

PHOTOSENSITIVE BLUEWARE

DESIGNERS: Tim Simpson and Sarah van Gameren STATUS: Research, ongoing

STUDIO GLITHERO

1 – System designed by Glithero for even exposure on doubly curved surfaces such as vases.

2 – The exposure patterns are generated by light shining through plants pressed between two panes of glass.

Founded in 2008 as a design studio, Glithero seeks to create work that expresses “the perfection and beauty in a moment of transformation.” The Blueware collection was inspired by the work of English botanist Anna Atkins—one of the first female photographers—who used cyanotypes to document specimens. The process uses a photosensitive solution of ferric ammonium citrate and potassium ferricyanide which, when exposed to UV light reacts to produce a cyan-blue. The result is a photogram, translating an object directly onto the photosensitive surface. Cyanotypes were widely used in architecture and engineering to create the original “blueprints.” Further researching the process, Glithero began an exploration of other ma-

EMERGING SYSTEMS

3 – The result is reminiscent of Anna Atkins’s biological specimen cyanotypes.

terials that might produce cyanotypes. A success in plaster led naturally to ceramics where the studio found an aesthetic parallel in the famous blue Delftware. Cyanotypes require a porous surface—eliminating glazed or porcelain ceramics—so the team used unglazed earthenware (5). However, unlike paper, ceramic can absorb chemicals deep into their complex pore structures and then slowly leach them over time, ruining the cyanotype. Glithero’s contribution to the field was not in the cyanotype process but the method of drying and washing the photosensitive solution on ceramic, a discovery that took over a year of research. Glithero has successfully produced large murals of ceramic tiles, utilizing traditional pattern techniques. Exposures

were created from arrangements of plants pressed between sheets of glass, which were then flipped to create mirrored patterns (2, 3, 4). Expanding into vases, they developed a special process to control the light exposure over the three-dimensional surface (1). The nature of the cyanotype does not make it suitable for applications involving high heat, light, moisture, or foot traffic. Despite a protective coating to preserve the image, to date Blueware has been installed primarily as interior decorative elements. Glithero’s ongoing research of the process led to the release of Silverware in 2013, and the designers believe that improving the durability of the treatment will open it to wider architectural applications.

4 – Flipping the glass panels and repeating the process on new tiles creates mirrored patterns.

5 – The cyanotype process is applied to unglazed ceramics.

199

FOAMED CERAMICS

DESIGNER: Marjan van Aubel STATUS: Research, ongoing

EUROPEAN CERAMIC WORK CENTER JORIS LAARMAN STUDIO BV

1 – Array of foamed ceramic material samples.

Foaming as a strategy to imbue new properties to solid materials is used widely for many polymers, metals, and other materials. While there has been much research and development in foaming technical ceramics, and applications such as ceramic filters are now widely used, there has been little progress on the same issue in claybased materials (1). Van Aubel is a Dutch designer with a knack for science—maybe due to a family background in chemistry.

EMERGING SYSTEMS

While at the European Ceramic Work Center, she developed a method to produce foams from a mix of 5–25% kaolinite, 10–30% of alkali metal salts and/or alkaline earth metal salts, 40–75% frit as well as other materials. After a low-temperature drying phase, kiln firing at temperatures between 800° and 1,200°C produces a rigid foamed material that expands approximately 300% compared to the solid bulk. Its density is 300– 400 kg/m2, considerably

lower than that of solid ceramic (2). The material structure is comprised of thermally insulating and water-resistant closed-cell pores (3). Glazing the foamed material adds robustness and strength. Initial applications by van Aubel included furniture and tableware objects, but building products and other objects can be developed as well (4, 5).

2 – Detail of the foamed material sample showing cellular properties and translucency.

3 – Foamed porcelain used to create a functional translucent vessel.

4, 5 – Foamed porcelain used to create a large-format ceramic sculpture.

201

ADDITIVE CERAMIC SYSTEMS 1 – Six-axis robotic work cell utilized to create prototypical large-format woven ceramic facade elements.

Additive manufacturing technologies (AMT), commonly discussed under the umbrella term 3D printing, is quickly emerging as an exciting field in technology development for architectural applications. Currently, a few relatively well-established processes are actively used in manufacturing functional parts or tooling for a variety of fields, including medical industries and aerospace applications. The promise of additive manufacturing is directly in line with contemporary trends in architecture and product design where the desire for complexity, both geometric and functional, intersects the demand for individualized customization—all of which are potentially available through the application of AMTs and are particularly possible through ceramic materials. Within a variety of AMT processes several have been explored in the context of clay-based ceramics. In particular, binder jetting has been commercialized to some extent. The process involves the controlled deposition of a liquid binder solution or other material onto a bed of powder that is supplied at a controlled thickness to build objects layer by layer to form rigid parts. This process emerged from the development of 2D inkjet printing technology and led to the coining of the term 3D printing, now commonly accepted in reference to all AMT processes. In common binder jet systems, the binder is deposited from standard inkjet printing heads that travel across the build chamber using a two-axis gantry system. The build layer remains at

EMERGING SYSTEMS

the same height, with all movement in the Z axis occurring in the build chamber itself. Existing binder jet systems range in size from small prototyping machines suitable for offices and classrooms to very large machines used in the production of tooling for foundries. The Z-Printer, a common binder jet prototyping system, is produced by 3D Systems/Z-Corp, and several third-party material vendors have developed retrofits that allow this system to print alternative materials such as ceramic powders. A vase produced by designer Jonathan Grinham was designed using the Rhino modeling platform and manufactured by Shapeways, a web-based print-to-order company capable of producing individual prints in a variety of materials using a number of AMTs (3, 4). When designing ceramic parts for binder jet 3D printing processes, specific parameters should be considered; some are material-specific and some imposed by process. Parameters include minimum and maximum wall thickness, limited overall thickness variation, build volume and part dimensions, aggregate thickness of material and glaze, and feature size. As binder jetting is a commercially available ceramic AMT process, details relating to cost, lead-time, and process parameters are variable. Additional AMTs, particularly through automated material extrusion, have also been explored in the context of ceramics but have yet to be commercialized. Contour Crafting, a process developed by Behrokh Khoshnevis at the University of Southern

2 – A printed facade element is developed for specific lighting effects through controlled density variation; created by students O. Mesa, H. Kim and J. Friedman at Harvard GSD.

California that now utilizes concrete to print entire buildings, began with the development of a ceramic printing process. It achieved relatively high surface finish quality compared to other related material extrusion processes. Other processes have emerged that utilize automated deposition of extruded material. Several designers have developed modified or custom desktop printers to deposit clay slips and slurries, layer by layer, to realize printed ceramics elements (5). In one example, artist Olivier van Herpt utilizes a custom designed delta robot to print detailed functional ceramics objects (6). Robotically controlled material deposition is the driving technology behind the prototypical shading lamellas created by the Design Robotics Group at Harvard University shown in this chapter (1). As an extension of these technologies, the Y-Form printing process utilizes a robotically (or otherwise) controlled extrusion device to print architectural-scale “woven” facade systems (2). This process, developed at the Harvard University Graduate School of Design, seeks to overcome a perceived limitation in the eventual architectural application of printed ceramic elements by circumventing the traditional layer-by-layer approach by using offset layers. Further expanding on this technique designers from the Rhode Island School of Design have developed a series of facade proposals that utilize systemic variation to enhance environmental facade performance (7).

3, 4 – A computationally designed vase produced using binder-jetting, created by designer Jonathan Grinham.

5 – Custom material deposition system using a delta robot platform that prints a ceramic vase, created by artist Olivier van Herpt.

6 – Precise material deposition enables the automated system to produce intricate patterns.

7 – Printed facade section directs lighting and view through controlled aperture variation; created by students C. Wang, H. Cheng and A. Baquerizo at the Rhode Island School of Design.

203

AUTOMATED MATERIAL MANIPULATION

1 – Robotically roll-formed clay process developed to create customized cladding systems by students at the Harvard University Graduate School of Design.

2 – Prototypical ceramic element formed through robotic wire cutting at the 2011 Smart Geometry Conference as part of the Ceramics 2.0 cluster.

In part as a result of a shifting industrial manufacturing landscape and overall cost reduction, and in parallel to emerging computational tools and automated machine programming workflows, industrial robots have been rapidly adopted in the production of art, architecture, and design. Industrial robots, whether individually or in collaborative work cells, are remarkably flexible devices. Where programming workflows and cost were once hurdles, designers now enjoy unprecedented opportunity to engage process as a mode of material exploration—whether through the invention of novel tooling or the adaptation of existing methods. While low-volume ceramics producers have yet to adopt the industrial robot, the intense design-driven development in this area leads to the obvious speculation that an increase in opportunities for robotically manipulated ceramic building components will occur. Early research has proven the technical feasibility as well as design potential of automated material manipulation within the context of architectural ceramics. Explorations in this context can be categorized as shaping and cutting (1).

The development of each technique seems to follow the same logic. First, researchers experiment with the varied automation of otherwise fixed or manual processes. Robotic cutting, which has largely been explored as a strategic intervention within the industrial extrusion process, has emerged through the development of custom end effectors or robotically driven tools that mimic existing operations but add additional degrees of freedom, such as in-line wire-cutting of ruled surface geometry (2). In other examples, variable blade or die cutting has been explored as a mechanism for creating families of like components. Robotic forming has been explored as a primary means of shaping ceramic elements either in-line with existing processes or as a standalone method. Here a clay slab or ball is supplied to the robotic work cell and, through automated control of custom end effectors, is shaped to form a desired geometry or effect. While these are computationally driven operations, early proof of concept explorations has shown that it is the behavior of the clay in combination with the automated tool that gives the final

EMERGING SYSTEMS

form. Vision sensing and other existing real-time feedback loops suggest that robotic material manipulation can become highly predictable (4). Typically the desire is to reduce the material variability and strive for precision, but in light of current ceramic industry trends we will likely see an embracing of material effects and the utilization of automated tooling to provide efficient craft-like products that can be produced in automated settings. The example shown in figures (1) and (4) represents early tests in the creation of robotically roll-formed facade elements by students at the Harvard University Graduate School of Design (5). In addition to external manipulation of materials, there are strategic process interventions that address process-specific tooling. Variable extrusion, for example, presents an exciting opportunity to create custom geometries while maintaining efficiency in the production process. As discussed in Chapter 4, the primary shaping mechanism during the extrusion process is a fixed die. Early research demonstrates, at least in part, the opportunity for variable extrusion through variability in the die itself (3).

3 a, b, c – Automated variable extrusion die enables surface variation while maintaining consistent wall thickness and detailing features. Created by N. King, C. Yurkovich, and D. Jimenez at the Harvard GSD.

4 a, b – Felix Raspall has developed real-time material feedback systems for the robotic manipulation of clay materials.

5 – Prototypical robotically roll-formed facade panel produced by students S. Cooke, B.Shin, R. Kotelova, and P. Sprowls at the Harvard GSD.

205

PRODUCTS AND TECHNOLOGIES

Much of this book has focused on the interesting and innovative ways ceramic is used as a central design element in architecture and interior design. In many cases architects and designers worked with manufacturers to produce bespoke systems unique to the project and its context. However, innovation in ceramics is not limited to the delivery of projects, and many product designers and manufacturers work to produce interesting and novel products, processes, or technologies, available in the market for every designer to utilize. From impossibly large tiles to nano-scale surface treatments—and everything in between—the world of ceramic products is constantly expanding. The product list of this section intentionally avoids common ceramic elements, assuming they are already familiar to designers, and focuses rather on products and opportunities likely to be unknown. Several products in this chapter even break with the traditional conception of ceramic as ‘cladding’ and explore ceramic furniture. Many of the surface treatments identified are infinitely customizable to creative designers willing to work with manufacturers. Whereas the previous chapter identified ceramic research that looks ahead to the future this chapter focuses on products and technologies that are available now, and yet perhaps unbeknownst to the average practitioner. To the reader these products may serve as the starting point for their next novel design solution or as the jumping off point into further research into the vast realm of ceramic products. The products in this chapter by no means represents a comprehensive list of innovative ceramic products—the contents of which would expand beyond this book—but rather were chosen to indicate the range and variety of products and technologies available. Likewise, the products and manufacturers identified are examples and do not represent a comprehensive list of products of a particular type or the manufacturers who produce them. The authors do not endorse products listed in this chapter but rather present them as indicative of the options available to designers.

LARGE-FORMAT PRODUCTION LINES Manufacturers: Sacmi Imola S.C.; System Ceramics Traditionally, dry-pressed tiles were limited in size due to air getting trapped in the tile body when the powder was compressed; the pressurized air would expand and cause breakage during firing. Conventionally pressed tiles remain under pressure long enough for the air to evacuate; however, the time required increases with the surface area and thickness of the tile, making this process uneconomical beyond certain limits. More recently, two companies have developed proprietary production lines capable of overcoming these limits. One type of line replaces the pressed mold method by compacting the dry powder under belts. The other type additionally finishes the process with a second compaction, using a traditional mold press.

LARGE-FORMAT TILES: NEOLITH, TECHLAM, MAXIMUM TheSize: Neolith; Levantina: Techlam; Fiandre: Maximum Several companies now offer large-format tiles that range over 1,000 × 3,000 mm in size and 3-5 mm in thickness. Variations can include adhered fiberglass backings to increase the tensile strength of the product. Neolith by TheSize is available in 3,600 × 1,200 mm and 3,200 × 1,500 mm formats in thicknesses of 3, 5, 6, and 12 mm. Manufactured entirely from clay, feldspar, silica, and mineral oxides, it is capable of bending to a surprising degree. These elements can be used to quickly cover large areas with the absolute minimum of tile and grout seams. With their flexibility and strength, they lend themselves to more creative applications like the 3DX1 installation (Chapter 9).

207

HIGH-STRENGTH PORCELAIN: SAPHIRKERAMIK SINK Manufacturer: LAUFEN Bathrooms AG Designer: Toan Nguyen The design of sinks provides an excellent representation of the limitations and opportunities of slip casting processes. Production typically takes place in high-volume settings that nevertheless involve a fair amount of hand labor. The use of porcelain slips in combination with the casting process limits designers: larger flat areas are rather difficult to produce, and edges need to be curved with radii of at least 7–8 mm. LAUFEN Bathrooms AG developed a proprietary slip casting process whereby slip is injected under high pressure into plastic molds, thereby increasing production speed as ceramic elements can be removed from the molds in approximately 10 minutes (as opposed to an hour). The company also developed a new ceramic material, called SaphirKeramik, which exceeds the typical strength of ceramic by a factor of two to three and has an average bending strength in the order of 120 MPa. The improved mechanical properties allow for sharper corners with bending radii as low as 1–2 mm. Extremely thin walls and slender features can be produced in this way, which typically would have required glass or steel for production.

BIOACTIVE CERAMICS: BIONICTILE Manufacturer: Ceracasa Cerámica In the 1960s scientists discovered the photocatalytic properties of titanium dioxide (TiO2), which off-gasses when exposed to water and UV light, in an oxidizing effect that destroys virtually all organic compounds. In the 1990s the laboratories of the world’s largest plumbing products manufacturer, the Japanese company TOTO LTD., combined the TiO2 coating with a super-hydrophilic surface and patented HYDROTECT®, a self-cleaning surface triggered by sunlight and rainwater. When hitting superhydrophilic surfaces, water does not form a contact angle so that it spreads, maximizes contact, and washes off cleanly. This process can be applied to glass, therefore also to glazed ceramics and more recently has been successfully applied even to unglazed ceramic. It does not impact the quality of the tiles and can therefore be offered on a range of standard products. BIONICTILE reacts with nitrogen oxide in the air, which is responsible for human health issues and acid rain, and converts it to nitrates. The product advertises that compared to conventional tiles, photocatalytic tiles reduce by 19% the potential for photochemical ozone formation.

PRODUCTS AND TECHNOLOGIES

SLUMPED TILE: UP Manufacturer: Aparici UP uses the slumping process described in Chapter 4 to create three-dimensional tile assemblies. Because they are cut from standard pressed tiles and re-fired in the slumping process, the products are available in any of the manufacturer’s porcelain collections. They are microsealed and frost-resistant and therefore can be applied indoor and outdoor. In UP there are two units, the “up” unit with a convex shape, and the inverted “down” unit with a concave shape; the depth of the units being approximately 40 mm. Wave patterns can be created by offsetting rows of one unit, while woven patterns can be created by alternating “up” and “down” units at right angles to each other. The units are generally 880 -1,180 mm long and range in widths from 50 -220 mm. A range of glazes and surface treatments is also available, allowing the final assembly to mimic wood or stone.

SLUMPED TILE: STAR Manufacturer: Porcelanico STAR also utilizes slumping to create three-dimensional tile assemblies. The units are cut from pressed tiles and re-fired to their final shape. STAR is inspired by the work of artist Erwin Hauer, known for his modular light-diffusing sculptures. The units are 600 × 600 mm and offset to create the visual effect of interlocking panels. They can be backlit for dramatic effect and to enhance the perceived depth. The panels are usable in both indoor and outdoor applications.

209

TRANSLUCENT PORCELAIN: SLIMMKER-LIGHT Manufacturer: Inalco Ceramic tiles have achieved remarkably sophisticated glaze finishes, yet until recently the claim of translucency had been beyond the reach of industrial producers. Inalco’s SlimmKer-Light technology is among the first to produce a translucent thin tile using an extremely pure, white clay body in combination with highly vitrifying firing techniques. The end product allows for the transmission of light, and is probably at its best when combined with artificial light sources. The translucent effect is enhanced by a polished relief pattern that scatters the light in different ways on the surface, resulting in slightly different tones. The white base material can become colored through the use of a colored light source.

MODULAR CERAMIC STOVE Manufacturer: La Castellamonte Designer: Adriano Design The combination of controlled radiating heat and convection heat continues to fuel the use of ceramic stoves. Their historical use especially in Northern Europe with cold winters and abundant fire wood waned with the introduction of central heating systems, but today’s trend towards site-based energy production has rekindled interest in a heating technology that became widely known through the Romans’ hypocaust systems. Many ceramic stoves feature ceramic elements on the interior to capture a large amount of the heat emitted by the fire, and distribute it slowly over hours through a combination of radiation and convection. The exterior ceramic enclosure further controls the heat distribution, and permits the same variety of glazed finishes generally available for tiles. Some stoves can be connected to a central heating system in order to coordinate temperature control. The system shown here offers a modular approach that allows the end user to configure units at different height and shape. Production techniques use slip casting and a clay body with particularly high alumina content. Glazes are manually applied after the initial bisque firing.

PRODUCTS AND TECHNOLOGIES

BERLIN STOVE TILES Designer: Daniel Becker Historical ceramic stoves feature ornate ceramic tiles often in bas-relief. The outer ceramic cladding consists of relatively thick tiles that contribute to storing and moderating the heat of the fire. Designer Daniel Becker conceived a contemporary stove tile that references a popular older German model commonly produced in blue and brown tones. The tile increases the surface area while referencing, at least vaguely, notions of pixelation and three-dimensional images. It can also easily be combined with flat versions to produce accents on larger surfaces.

KERAMOS CABINETS Manufacturer: La Castellamonte and Adriano Design Ceramic stoves blend performance with a scale akin to furniture. Taking this established concept one step further, a ceramic outer shell forms the core element of this modular cabinet. Typically two ceramic elements are joined through a tongue-andgroove system of wood connectors. Wooden doors, inner shelves, and legs complete the element. The toy-like appearance is enhanced through the use of brightly colored glazes. The ceramic shells are slip cast and designed to avoid any sharp corners, thereby expressing the logic of the casting process and the materiality directly, juxtaposing it with the rectilinear nature of the doors.

INKJET-PRINTED TILES: EMOTILE Manufacturer: Ceracasa Cerámica Translating inkjet technology into the ceramic industry involved a high degree of precision to coordinate the data feed, printing, ink supply system, and tile transport system, and “their integration into a robust, reliable and precise machine capable of operating continuously with minimal maintenance in a ceramic production environment.”1 The development of suitable glazes was also a major challenge. The complex rheological properties of liquids, such as viscosity and surface tension, play a significant part in the size and formation of droplets, critical to the drop-on-demand inkjet printheads. The printability of certain glazes is therefore limited. In particular, colored glazes are typically either finely ground pigments or soluble metallic

211

compounds that react during firing to create the desired color. For inkjet printing, solid particles can alter the liquid viscosity, clog printheads, or lead to sedimentation. For these reasons, in the past, the limiting factors for ceramic inkjet printing have been image resolution and color quality. As these technical challenges have been overcome, manufacturers like Ceracasa Cerámica have offered mass-customized product lines like Emotile. Practitioners provide the image, set the overall project dimensions, and size of tile to be used. The manufacturer handles the rest.

PHYSICAL VAPOR DEPOSITION: METALLIC COATINGS Manufacturer: Emozzioni by Titanium In the field of nano-technology, physical vapor deposition (PVD) is the deposition of a thin film of vaporized material. The process is physical rather than chemical, relying on high-temperature vacuum evaporation or plasma spraying. By applying various metals and alloys, specific physical and aesthetic qualities can be achieved, like highly controlled metallic colors and effects by customizing the light reflection properties of the specific deposition layers. Titanium coatings can be applied—as in the case of bioactive coatings— as well as gold and platinum coatings. Iridescence can be achieved by selecting the coatings according to an effect known as thin film interference. Physical vapor deposition is a well-known family of processes with origins dating back to the 19 th century. While previously used exclusively in high-tech products or scientific research recent years have seen its expansion into other manufacturing contexts. Its use on ceramics by manufacturers like Emozzioni to produce metallic coatings represents one new permutation of this technology.

PRODUCTS AND TECHNOLOGIES

LASER ENGRAVING Manufacturer: Pamesa CNC laser cutters are another example of a technology originally developed for a different purpose that has expanded into the world of ceramics. Laser engraving offers a new way of decorating ceramic tiles in a highly customized way, with manufacturers like Pamesa offering it as a secondary treatment option on their product lines. One method is to use the heat of the laser to create microcracks that remove the surface of the ceramic at the microscale. For high-gloss glazes this ablation removes the polished effect and can create subtle patterns of polish and matte. The laser uses bitmaps, essentially fields of dots, to drive the pattern-creating gradients through the density of dots. A second method uses the laser to cut the ceramic. The ensuing patterns are linear and driven by vector files. A third method uses traditional glazing material combined with thermal absorbers. The laser then acts as the heat source to fuse ceramic glaze in a highly controlled way.

RECYCLED TILES Manufacturers: Porcelanosa, Royal Mosa, Fireclay, Daltile, Terra Green Ceramics Ceramic tile production in both craft and industrial settings is material-efficient in that all production waste can be easily recycled. Many manufacturers advertise that production waste is recycled, without however mentioning that modern production equipment has reduced waste to the largest possible degree. Some larger manufacturers efficiently collect all production waste and process it for new production. Porcelanosa, for example, offers a porcelain tile with 95% pre-consumer recycled content. Royal Mosa offers Cradle-to-Cradle-certified tiles with 21–45% pre-consumer recycled content. The use of post-consumer ceramic materials is not as common, in part because prior to recycling tiles from the demolition waste, all mortar and adhesive needs to be removed—a labor-intensive process hardly economical. Compared to tiles, toilets and other ceramic bathroom appliances produce cleaner ceramic recycling streams. Several tile manufacturers now offer ceramic tiles with a high percentage of post-consumer recycled content. Fireclay, a California-based company, produces tiles with 70% recycled content consisting of curbside recycled glass, waste porcelain from toilets and bathtubs, as well as granite stone dust from a local quarry. Daltile has ceramic tile with 10% pre-consumer and 30% post-consumer content. Terra Green Ceramics features a tile made from a mix of virgin clay and 55% recycled glass. PREASSEMBLED SYSTEMS: FLEXBRICK Developers: Piera Ecocerámica, Cerámica Malpesa, and Dr. Vicente Sarrablo Flexbrick is a new construction system that features a wire mesh onto which ceramic extrusions are mechanically hooked. The prefabricated elements of the wire ceramic system are connected to the building structure. The basic hollow extruded tile of this system measures 243 × 97 mm with a thickness of 30 mm. Its profile is designed with

213

a chamfered side channel that allows the tile to be quickly pushed into the flexible steel mesh. Leaving mesh modules free of tiles can produce the effect of a perforated screen. The elements are typically hung vertically as facades, but they can also be installed on roofs or other surfaces. The tiles are left natural with their red clay body, or they can be glazed in a range of colors and surface effects. More robust tile versions can be used for floor applications as well.

CERAMIC–CONCRETE COMPOSITE SYSTEM: TERRACLAD Manufacturer: Boston Valley Terra Cotta and other manufacturers An alternative to adhesive bonding or mechanical connection is to embed special tile shapes into concrete during the concrete placement process. The TerraClad system features specially profiled ceramic tiles designed for concrete pre-cast panels and other elements. The tiles measure up to 1,524 mm × 610 mm with a thickness of 30 mm. Their back features a dovetail-shaped profile designed to permanently bond to the concrete. Hollow core extrusions complement the flat profiles to create sills and other details.

CERAMIC LOUVER SYSTEM: SHAMAL Manufacturer: Terreal The Shamal System offers a selection of shaped louver products that, together with the system’s aluminum structure, can be configured to shade facades for a broad range of locations and seasons. The ceramic louver is a hollow extrusion, produced in terra cotta and available in a range of unglazed or glazed finishes. The system components allow the louver spacing and inclination to be individually adjusted. Tabulated data guide designers at least in the initial product selection process. The maximum profile length is 1,290 mm, a span that can be supported without an interior metal profile.

PRODUCTS AND TECHNOLOGIES

PHOTOVOLTAIC ROOF TILES: PANOTRON Manufacturer: Gasser Ceramic Many building energy codes require that a certain amount of energy be produced on site, and photovoltaic (PV) technology is by far the most frequent solution to satisfy electricity needs. Visual integration of the panels can be challenging, especially for roofs covered with ceramic roof tiles, as the small-scale tiles combine with difficulty with the relatively large PV panels. Gasser Ceramic offers a system whereby a small PV panel is integrated into a specially designed ceramic roof tile. The tile measures 450 × 255 mm and is suitable for roof slopes between 17° and 60°. The system can generate up to 70 W/m2, and no tile penetrations are needed to accommodate cables and other system components. As the PV cells need to be replaced during the service life of the roof tiles, the system allows the PV panels and tiles to separate through specially designed mechanical connectors. Used PV elements can be returned to the company for recycling.

CERAMIC WARDROBE: MILKY STAR Manufacturer: POLI Keramik GmbH Designer: Pudelskern Many tile products for bathrooms offer special pieces that integrate soap dishes and other features directly into tiles. The Milky Star tile system takes the same principle to living areas. It consists of a single base tile with a slight surface camber and interlocking features not unlike the elements of a jigsaw puzzle. The design allows for the tiles to be assembled into a highly ornamental, textured surface. The same base tile is available with an integrated coat hook, permitting the wall cover to be used beyond its decorative value. The shape was inspired by forms found in microscopic views of the Ornithogalum dubium flower. The tile has also been used as an exterior cover for heat-emitting walls and ceramic stoves.

215

ACOUSTIC CERAMICS: ACOUSTIC SHINGLE Manufacturer: Terreal Acoustic shingles are one of several ceramic acoustic panel systems offered by manufacturer Terreal. The systems include extruded ceramic elements mechanically attached to metal substructures. The elements are perforated and filled with sound-dampening mineral wool. The acoustic panels can be matched with non-perforated panels of the same type to allow projects to customize the acoustical properties of the surface. The acoustic shingle measures 300 × 1,400 mm, with a wall thickness of 70 mm and perforations of 14 mm. The durability and easy maintenance of the ceramic is combined with the sound absorbance needed for large high-traffic interior or exterior public spaces. INDUSTRIAL TILE: ACIGRES Manufactuer: Brancós Ceramics Acigres combines the mechanical strength of highly vitrified clinker bricks with the properties of acid-resistant tiles, resulting in a high resistance to abrasion, thermal shock, acids, and alkalis. The tiles can be adhered with a two-component acid-resistant epoxy in order to ensure the surface is completely resistant to harsh chemicals.

NOTE 1 Hutchings, Ian. “Ink-jet printing for the decoration of ceramic tiles: technology and opportunities”. In: Proceedings Qualicer, XI: Forum on Ceramic Tile, Castellón 2010.

MATERIAL MIMICRY: AGE WOOD, AGE BETON, AGE BLEND Manufacturer: Pamesa Cerámica Inkjet technology is used here to apply individual glaze patterns to lend each tile a unique texture associated with wood. Along with Age Wood, the manufacturer produces Age Beton, which simulates concrete, and Age Blend, which merges wood and concrete textures.

PRODUCTS AND TECHNOLOGIES

APPENDIX

ABOUT THE AUTHORS

MARTIN BECHTHOLD is Professor of Architectural Technology at the Harvard University Graduate School of Design (GSD), and Associate Faculty at the Wyss Institute for Biologically Inspired Engineering. He was Baumer Visiting Professor at Ohio State University, and Visiting Professor at the Institute for Structural Design at the Graz University of Technology, Austria. He directs the GSD’s Doctor of Design program and is the Founding Director of the school’s Material Processes and Systems Group (MaPS). Bechthold is the co-author of Structures (7th edition, Prentice Hall, 2013), Digital Design and Manufacturing (Wiley, 2004) as well as the author of Innovative Surface Structures (Taylor & Francis, 2008), a book that addresses the increasing conflation of structural design and digital fabrication techniques through the microcosm of thin shells and membranes. Bechthold has taught workshops and lectures internationally. His design research on ceramics has been exhibited annually at the Valencia-based CEVISAMA since 2012. He was awarded the 2014 ACADIA Innovative Research Award of Excellence. ANTHONY KANE is Vice President of Research & Development at the Institute for Sustainable Infrastructure in Washington, DC. His work focuses primarily on sustainability in the built environment and advanced fabrication methods. He is a contributing author of Infrastructure Sustainability and Design (ed. Spiro Pollalis et al, Routledge, 2012) and has published articles for the International Symposium on Automation and Robotics in Construction (ISARC). His work is also featured in Fabricating the Future (Philip F. Yuan et al, Tongji University Press, 2012). Kane was formerly a research associate with the Material Processes and Systems Group at Harvard University, and an instructor at the Boston Architectural College. NATHAN KING is Assistant Professor of Architecture at the School of Architecture + Design at Virginia Tech, and has taught at the Harvard University Graduate School of Design (GSD) and The Rhode Island School of Design (RISD). With a background in Studio Arts and Art History, Nathan holds Masters Degrees in Industrial Design and Architecture. He earned the degree Doctor of Design from the Harvard GSD where he was a founding member of the Design Robotics Group. Beyond academia, King is the Director of Research at MASS Design Group, where he collaborates on the development and deployment of innovative building technologies, medical devices, and evaluation methods for global application in resource-limited settings. He consults on the development of research facilities, programs, and software to support the exploration of emerging opportunities surrounding technological innovation in art, architecture, design, and education.

APPENDIX

INDEX OF NAMES # 2x4 Inc. 98 3D Systems/Z Corp 202 3Dx1 112–113, 207 3LHD 94 A Aalto, Alvar 16 Acigres 216 Adler & Sullivan 15 Adriano Design 210, 211 Age Beton 216 Age Blend 216 Age Wood 216 Agrob Buchtal GmbH 72, 98 AIA Upjohn 194 Alberta Legislature Building dome reconstruction, Edmonton 170–171 Algueña MUCA Music Hall and Auditorium, Alicante 74–77 Ali, Muhammad 98 Allan Merrick Jeffers 170 Alumeyer 130 Amat, Frederic 150, 151 Andreani, S. 196 Aparici 209 Aragonia project, Zaragoza 49 Archeological Park, Xanten 15 Architech by Floor Gres 94 Artaic 104 Arts Ceramics Studio, Harvard University 35, 36 Arts Council, Madrid 120 Arup 98 ASCER Tile of Spain 190, 192, 196, 223 Atkins, Anna 196 B Baquerizo, A. 203 Barkow Leibinger 172 Bauhaus, Weimar 16 Bechthold, Martin 87, 190, 192, 196, 218 Becker, Daniel 211 Beehive Project, regional library, Pécs 40 Bellido, Luis 120 Benidorm West Beach Promenade 65, 80–81 Bennett, Trew 35 Beyer Blinder Belle Architects & Planners 98 Bierman Henket Architects 184 Bingham, Howard 98 BIONICTILE 208 BIO SKIN 144 Bios Self-Cleaning 84 Blok, Maree 46 Boston Valley Terra Cotta (BVTC) 31, 126, 170, 214 Braas GmbH 54 Brancós Ceramics 216 Buck Creek Pottery 35, 36 Building Science Engineering Ltd. 170 C Campos Costa Arquitectos 180 Capitol Designer Studio (CDS) 88 Casa Batlló, Barcelona 54 Casalgrande Ceramic Cloud (CCCloud) 87, 114–117

Casalgrande Padana S.p.A. 84, 114, 117 Center for Architecture, Science and Ecology, Rensselaer Polytechnic Institute 194 Centre Georges Pompidou 17 Ceracasa 82, 208, 211, 212 Ceràmica Cumella 34, 100, 140, 149–150, 154, 176, 177, 180 Ceràmica Elias 10 Cerámica Malpesa 213 CeraVent 52 Chassay+Last Architects 65, 66 Cheng, H. 203 Chermayeff, Peter 180 Cole & Son 66 Congress Building, Zaragoza 55 Contour Crafting 202 Cooke, S. 205 COR asociados 74 Cortile del Priore dell’ex Maternità, Bologna 84, 85 Craven, Nathan 162 Cretaprint 82 Curtainwall Design Consulting (CDC) 126 D Daan, Gunnar 184 Daltile 213 Deacon, Richard 78, 79 Decorativa Tozeto S.A. 106, 136, 140, 154 Decq, Odile, see Studio Odile Decq Design Robotics Group at Harvard University Graduate School of Design 190, 192, 202 Dieste, Eladio 16, 196 Dietrich, Niels 90 Disset 140 Djoser, Pharaoh 13 Djoser Pyramid 13 Dorent, Nathanael 88 E Elfstedenmonument bridge 46 Emotile by Ceracasa S.A. 211 Emozzioni by Titanium 212 Ennead Architects 44 Enric Miralles and Benedetta Tagliabue (EMBT) 100 Eric Parry Architects 70, 78 Esteve, Ramón 47 European Ceramic Work Center 200 F Fachverband Baustoffe und Bauteile für vorgehängte hinterlüftete Fassaden e.V. 46 Ferrater, Carlos 80 Ferreira, Pedro 124 Fiandre 207 Fireclay Tile 213 Flexbrick system 11, 213 Floor Gres 94 Flores, Paulo 106 Florim Ceramiche S.p.A. 94 Foamed Ceramics 200–201 Foreign Office Architects (FOA) 154 Francisco Ramón Borja SA 120 Franco, Arturo 61, 120 Friedman, J. 202 Fundación CENER-CIEMAT 140 G Galí, Xavier Martí 80 Gasser Ceramic 215 Gaudí, Antoni 11, 34, 54, 100 GGlab 106

Gibbs and Canning 170 Giraud Frères 17 Glithero, see Studio Glithero Graniti Fiandre S.p.A. 112 Grão – Ceramic Pixels, Belém 119, 124–125 Graz University of Technology 196 Grinham, Jonathan 34, 202, 203 Guaranty Building, Buffalo 16 Guastavino, Rafael 16, 196 H Harrison, Shay 194 Harvard University Graduate School of Design 190, 192, 202, 204, 205 Hatori, Tatsuyu 144 Hauer, Erwin 209 Herz, Manuel, see Manuel Herz Herzog, Thomas 17 Herzog & de Meuron 65, 72 High-performance Masonry System (HpMS) 194 Hinz, K. 196 Holburne Museum extension, Bath 70–71 HYDROTECT 208 I IKON 5 Architects 31 Imbern, M. 196 Inalco 210 Instituto de Tecnología Cerámica (ITC), Castellón 25, 80 Integrated Environmental Design-to-Robotic Production 192–193 Iowa State University, Mural, Ames 104–105 IRCAM studio 17 Ishihara, Yoshito 144 Ishtar Gate of Babylon, Pergamon Museum 14, 15 Israel Museum, Jerusalem 52, 130–133 Italian Ceramic Center 59 Iturralde y Sagüés Ingenieros 140 J Jacobsen, Arne 16 James Carpenter Design Associates Inc. (JCDA) 130 Jardim Botânico Tropical, Lisbon 124 Jaume I High School, Valencia 47 Jencks, Lily 88 Jewish Community Center, Mainz 90–93 Jimenez, D. 205 João, Rita 124 Joris Laarman Studio BV 200 K Kane, Anthony 190, 192, 218 Kawashima, Norihisa 144 Kengo Kuma and Associates 87, 108, 114 Keramia Ceramicas 80 Keramos Cabinets 211 Kéré Architecture 134 Khoshnevis, Behrokh 202 Kindergarten, Gandía 48, 49 Kim, H. 202 King, Nathan 190, 192, 205, 218 Kosemo Brick, Archie Bray Foundation, Helena30, 162–165 Kotelova, R. 205 Krobath, Barbara 55 Kuma, Kengo, see Kengo Kuma

219

L La Castellamonte 210, 211 La Mandarra de La Ramos restaurant, Pamplona 82, 83 La Riera de la Salut Remodel, Saint Feliu de Llobregat 176–179 LAUFEN Bathrooms AG 208 Laufen ceramic factory 34 Learning to Fly (Sealine) 104 Lee, A. 196 Levantina y Asociados de Minerales S.A.U 207 Libeskind, Daniel, see Studio Daniel Libeskind Architect Lohhof quarter, Munich 17 Ludowici Roof Tile 54 Lugthart, Bas 46 Lynch, Peter 158 M Mahou San Miguel Group 82 Mangado & Asociados S.L. 140 Mangado, Francisco 44, 55, 140 Mansfeld, Alfred 130 Manuel Herz Architects 90 Marazzi Group 88 Material Processes and Systems Group at Harvard University 196 Maximum Fiandre Extralite 112, 207 McGee Pavilion, Alfred University 31 Mengjia Longshan temple, Taipei 15 Mesa, O. 202 Metasus, see Studio Metasus Michalatos, P. 190, 192 Milky Star 215 Ministry of Urban Development and Environment, Hamburg 9, 51, 166–169 Miralles, Enric see Enric Miralles Moeding Keramikfassaden GmbH 17, 130 Moneo, Rafael 49 Morimura, P. T. see P. T. Morimura Mosa 213 Mosque, Saint Petersburg 9 Moussavi, Farshid 154 Muhammad Ali Center, Louisville 87, 98–99 Museum Brandhorst, Munich 68–69 Museum de Fundatie extension, Zwolle 184–187 Museum der Kulturen Basel 64, 65, 72–73 N National Museum of American Jewish History, Philadelphia 44 National Renewable Energy Centre (CENER) 140 National Terra Cotta Society, USA 15 National Tile Museum, Lisbon 124 NBK Architectual Terracotta 31, 68–69, 90, 166–167, 172 Neolith 207 New York Times Building 53 Nikken Sekkei Ltd. 9, 144 Nikken Sekkei Research Institute (NSRI) 144 Niwa, Katsumi 144 NOUS Engineering, London 88 O Oak Structural Design Office 108 Oceanário Addition, Lisbon 180–183 Office of Architecture Barcelona (OAB) 65, 80 Olivares, Jesús 74 One Eagle Place, London 78–79 P Pamesa Cerámica 213, 216 Panotron AG 215

APPENDIX

Paredes, Angela 49 Paredes Pedrosa arquitectos 48 Parry, Eric, see Eric Parry Patio 2.12 pavilion 50, 136–139 Pedrita 124 Perkins+Will 126 Photo mural, Amsterdam showroom 65 Photosensitive Blueware 198–199 Piano, Renzo, see Renzo Piano Picharchitects 11 Piera Ecocerámica 213 Pinnacle, Bologna 65, 84–85 Pol Femenias Arquitectes 176 POLI Keramik GmbH 215 Porcelanico 209 Porcelanosa 10, 213 P. T. Morimura & Associates Ltd. 108 Pudelskern 215 Pulsate, Primrose Hill, London 88–89 R Ramón Esteve studio 47 Raspall, F. 196, 205 Renzo Piano Building Workshop 17, 53 Rhinoceros 170, 190, 202 Rhode Island School of Design 202, 203 Richardson, Henry Hobson 16 Rodenas, Miguel 74 Royal Tichelaar Makkum 46, 184 Ruiz-Geli, Enric 150 S Sacmi Imola S.C. 207 Sagrada Família, Barcelona 34, 149 Santa Caterina Market, Barcelona 54, 87, 100–103 SaphirKeramik 208 Sarrablo, Vicente 213 Sauerbruch Hutton 9, 68, 166 School Library, Gando 134–135 Sealine, Eric 104 Sever Hall, Harvard University 16 Shamal 214 Shapeways 202 Shaws Glazed Brick Company 66 Shaws of Darwen 66, 70, 71, 78 Shin, B. 205 Simpson, Tim 198 Sistem N tiles 88 Skidmore, Owings & Merrill (SOM) 194 SlimmKer-Light 210 Sony Building, Osaka 9 Sony Research and Development Office, Tokyo 119, 144-147 Spanish Pavilion at the 2005 Exposition in Aichi 33, 154-157 Spanish Pavilion for the 2008 International Exposition in Zaragoza 30, 140–143, 162 Sprowls, P. 205 STAR by Land Porcelánico 209 Stelling House, Copenhagen 16 Structural Ceramic Shell 196–197 Student Services Building, University of Texas, Dallas 126–129 Studio Daniel Libeskind Architect 65, 84, 85 Studio Glithero 198 Studio Metasus 158 Studio Odile Decq 112 Sullivan, Louis 15 Su, Q. 196 Sydney Opera House 16 System Ceramics 207

T Tagliabue, Benedetta 100 Techlam 207 Technische Universität München (TUM) 17 Tegula Tile 194 Teresianas School, Barcelona 11 TerraClad 214 Terrados Cepeda, Javier 136 Terra Green Ceramics 213 Terreal 214, 216 Thermally active building envelope 194–195 TheSize 207 Tile Association, UK 46 Tile Council of North America 46 Toan, Nguyen 208 Török és Balázs Építészeti Kft 40 Toto Ltd. 144, 208 Trencadís 54 Trummer, A. 196 Trumpf Industrial Campus Restaurant 172–175 Tweebronnen School 16 U University of Southern California 202 UP by Cerámicas Aparici S.A. 209 Urban Guerrilla, Valencia 106–107 Utzon, Jørn 16 V Valencia Territorial Association of Architects (CTAV) 106, 107 Van Aubel, Marjan 200 Van de Velde, Henry 16 Van de Worp, Manja 88 Van Gameren, Sarah 196 Van Herpt, Olivier 202, 203 Venus of Dolní Věstonice 12 Villa for an industrialist, Shenzhen 158–161 Villa Nurbs, Empuriabrava 31, 150–153 Vollen, Jason Oliver 194 W Wallpaper Factory, Islington 65, 66–67 Wang, C. 203 Warehouse 8B Administrative Offices, Madrid 61, 120–123 Wienerberger GmbH 54 Winn, Kelly 194 Wright, Frank Lloyd 16 Xinjin Zhi Museum, Chengdu 108–111 XWG Architecture Studio 106 Y Yamanashi, Tomohiko 144 Yung, Ahlaiya 158 Yurkovich, C. 205 Z Zaera-Polo, Alejandro 154 Zamet Centre, Rijeka 94–97 Z-Printer 202 Zsolnay 74

SUBJECT INDEX A acoustic 53, 120, 216 Additive Manufacturing (AM) 202–203 adhesive 8, 40–43 aluminum 48, 51, 53, 61, 90, 95, 126, 130, 145, 166 aluminum oxide 80 anagama firing 36 automation 8, 14, 27–28, 37-38, 87, 104, 166, 188, 190, 192, 202, 204 B baguette 30, 52 bas-relief 64, 66, 84 bisque 27, 74, 166, 211 bonded facade 11, 46, 53 brittleness 18, 22, 86, 112 C capillary action 21 ceramic vessel 13, 15 Greek 12 Chinese 13–14 Neolithic 12 chemical resistance 25, 43 clay 18–20 additives 19–20 color 20 density 20 mining 58 pit 57–58 recycling 58–61 reinforcement 20 residual 18–19 sedimentary 18–19 slab 31, 151 types 18–20 clay body 19–21, 28–32, 43 green 21 particle size 21 shrinkage 21 corner detail 45, 129, 183 corner solutions 51, 52 cyanotype 198–199 D daylight 119, 126, 130, 134, 137 die 29, 30, 33–34, 51, 90, 100, 140, 162, 167, 177, 180, 204 die-cutting 31–32 disassembly 43, 51, 118 dome 170–171 draft angle 33 dry pressing 28–32, 41, 52, 75, 207 E earthenware 13, 19, 20 embodied energy 35, 57, 59, 61, 63, 140 enamel 74, 81 evaporative cooling 9, 22, 50, 118, 136, 140, 144 expansion joint 47–48 external insulation 48, 52 extrusion 29–33, 48, 51, 53, 91, 136, 140, 146, 148, 163, 166, 176

F feldspar 18, 22, 207 fiber reinforcement 20, 41, 52 fire clouds 13 foam, ceramic 119, 200–201 firing cone 37, 125 firing pit 13 freeze-thaw 20, 46, 54, 170 frost resistance 65, 74, 209 G glass 9, 13, 20, 22, 59–63, 131, 144, 163, 198 glaze colors 22–24 iridescent 74 metallic 64, 73, 75, 85, 107, 212 mirror 64, 72 photocatalytic 65, 84, 145, 209 self-cleaning 8, 65, 85, 209 texture 13, 24, 28–29, 38, 41, 65, 95 two tone effect 66 transfer 78 granite 19, 63, 213 grout 8, 38, 41, 43, 47, 101, 124, 158, 190 H hydration 18 hydrophilic 65, 84, 208 I igneous rock 18 inkjet printing 17, 39, 65, 82, 211 installation 13, 30, 32, 39–40, 43, 47, 49, 62, 104, 125, 158, 166, 176, 184, 191 interlocking 45, 71, 121, 163, 209 J jiggering 35 K kiln anagama 36 computer-controlled 8, 14, 37, 38 cross-draft 14 efficiency 59 energy consumption 51, 57, 59, 62 schedule 37–38, 150 shuttle 35 tunnel 35, 37 wood fired 36 L LEED 61, 126 life cycle analysis 57, 60, 63 life cycle design 56 M mass-customization 26, 149–150 mass-production 10, 39, 27 mold 51, 67, 72, 107, 150, 155–156, 159, 174, 180, 192 convex 21 design 21, 30–33, 35 plaster 16, 35, 51, 66, 72, 106, 186 polystyrene 31, 106, 151 mosaic 14–15, 41, 43, 46, 86–88, 98, 100, 104, 124, 190 P particle size 21 phase change material 194 photovoltaic 55, 215 pipes 19, 53, 144

plastic deformation 31 plastic pressing 32–33, 51, 154, 172, 180, 184 porcelain 15, 19–23, 37 porosity 18, 22, 42, 118, 136, 141, 145, 198 post-processing 11, 26–27, 38 potter’s wheel 12, 35 pottery 12–14, 17, 19, 35, 134 prefabrication 14, 39, 47, 137, 167, 213 pressure casting 34, 208 print, 3D 202–203 production craft-based 10, 26 dry 26 high-volume 10, 26–27 medium volume 10, 26–27 wet 26 R rainscreen 16, 50, 66, 78, 91, 99, 150, 170, 172 raised floor 43, 61 ramp test 25, 42 reclamation 60, 120, 124 rectification 28–29, 39, 192 recycling 8, 51, 56–58, 60, 63, 213 restauration 170–171 robotic extrusion 192, 202 forming 204 glazing 166 installation 190 mosaics 87, 104, 190 packaging 38 technology 27–28, 188 roof tiles 9,14–16, 19, 23, 33, 54–55, 60–61, 72, 87, 100, 108, 120, 150 S sanitary ware 23, 33, 35, 39, 45, 66 screen 11, 45, 51–53, 108–109, 120–123, 130–133, 144, 154, 162, 180, 214 sealant 10, 48, 63, 136 shading lamella 30, 53, 119, 126, 192–193 shell 16, 196, 211 shrinkage 15, 21, 30, 59, 70, 106, 140, 149–150, 166, 170 silica 13, 18-20, 22, 53, 207 sink 19, 22, 45, 61, 66, 70, 208 sintering 18, 30, 31, 37–38 slab roller 31 slip 19, 33–34 slip casting 19, 33–34, 45, 54, 66, 70, 72, 78, 149, 158–159, 196–197, 202, 208 hollow 33 solid 33 slip resistant 25, 28, 42, 55, 65, 80 slump molding 31–32, 150 slumping 29, 31–32, 51, 150, 209 slurry 34, 70 spalling 22, 47 stair tread 21, 29–32 stoneware 19-23, 42 stove 210 strength bending 22, 41–42, 51–52 compressive 22, 114 tensile 18, 207 slumping 151-153, 209 sub-surface 48, 87 sun shading 53, 119 surface effect 64 surface treatment 25

221

T technical ceramics 9, 53, 201 terra cotta 15, 19–22, 47, 60 tesselate 86 thermal expansion 48, 54, 180 thermodynamics 56, 118 tile adhered 38, 40–43, 47–48, 52, 55, 60, 62, 74, 100, 172 bullnose 41 curved 9, 31, 52, 151–153, 168, 209 dry-pressed 28–29 encaustic 64 extrusion 21, 29–31, 141, 145, 163 floor 10, 14, 25, 30, 38–39, 41, 43, 60, 63, 82, 89, 95, 214 full body 29, 42, 54, 60, 64, 94 hand-molded 10, 106, 109, 150, 159 laminated 41, 52, 113 large-format 41, 52, 87, 113, 207 mechanically connected 41, 43–44, 55, 52, 60 mosaic 14–15, 41, 43, 46, 86-88, 98, 100, 104, 124, 190 outdoor 47, 90–91 overview 40 plastic-pressed 21, 33, 51, 155 porous 18, 22, 42, 118, 136, 141, 145, 198 recycling 8, 51, 56, 60, 213 relief 14, 29, 33, 67, 159, 172, 210, 211 service life 60 slip-cast 33–34 texture 13, 25, 28-29, 41, 94, 215–216 wall 10, 31, 41, 47, 55, 67, 71, 82, 90, 94, 125, 136, 159, 172, 209, 215 toilet 19, 34, 45, 61, 213 tolerances 41 tooling cost 10, 28, 31, 33, 35, 163, 197 trencadis 56, 100 V ventilated facade 49, 50–52, 136–139, 166–169 embodied energy 63 gasket 50 operational energy 51 substructure 52, 91 tile 52, 90–93 vitrification 21–22, 25, 75, 81 W water absorption 136, 138 wheel-throwing 36 whiteware 35 wind load 41, 55, 126

APPENDIX

NETWORK OF KNOWLEDGE: ASCER TILE OF SPAIN 1

2, 3

4

The fragmentation of the building industry

the Valencia area as a center of production,

called Trans/Hitos, and curated by the Insti­

has often been cited as one of the main

based on the presence of extensive clay

tute for Ceramic Technology (ITC). The show

reasons for the slow rate of innovation and

sources. ASCER analyzes and publishes

features the year’s best work done by stu­

progress in the construction sector. Many

industry and market trends, and supports

dents in the different Ceramic Tile Studies

construction materials and building systems

the annual Tile of Spain awards in the cate­

Departments (figure 4).

today indeed seem all too similar to what

gories Architecture, Interior Design and Stu­

was the state of the art of construction

dent Work. Judged by an international jury of

nologies and design is of primary impor­

technology 100 years ago, certainly when

experts, the award winners include a House

tance in the competitive market of tiles and

comparing the building industry to quickly

in Príncipe Real (2014, architects: Camarim,

building­specific ceramic systems.

advancing fields such as automotive or aero­

figure 1), the La Riera de la Salut remodel

The Institute for Ceramic Technology (www.

space engineering and manufacturing.

project (2013, architect: Pol Femenias, see

itc.uji.es) in Castellón has become one of

pages 176­179) and the Catering School in

Europe’s leading institutions in this domain.

producers recognized the need to form a

the former abattoir in Medina Sidonia Cádiz

It is supported by the network of producers,

strong industry alliance to advance collec­

(2012, architects: Sol89).

the European Union as well as the Valen­

Starting in 1977, the Spanish ceramic tile

The support of research in ceramic tech­

tive knowledge about ceramic design and

ASCER also supports an international

technology. ASCER (Spanish Ceramic Tile

network of academic study groups at the

cia Regional Government. Working with producers and other stakeholders, ITC has

Manufacturers’ Association, www.ascer.es)

Spanish universities in Madrid, Barcelona,

extensive laboratory and prototyping facil­

was founded and today represents approxi­

Castellón, Alicante and Valencia, as well

ities. ITC studies have addressed a broad

mately 135 Spanish tile producers that gen­

as research and teaching at Liverpool Uni­

range of topics from lifecycle analysis, ceramic chemistry and glaze processes to

erate 95 % of the national tile production.

versity, the TU Darmstadt and the Harvard

The activities of ASCER are supporting re­

University Graduate School of Design.

innovative installation and recycling strat­

search, contributing to the dissemination of

The educational effort provides opportuni­

egies (figures 2, 3). The combined research

knowledge and supporting education at the

ties for students and faculty to engage in

and educational effort by ASCER and other

university level as well as for design profes­

a contemporary material system not just

ceramic­related groups has positioned

sionals and industry stakeholders.

theoretically, but with the integration of

Spain’s ceramic industry as a leading center

hands­on and industry­related activities.

of knowledge. The Spanish ceramic industry

Based in Castellón, Spain, ASCER is locat­ ed in immediate proximity to the majority of producers that have long established

“ExpoCátedra” is the annual exhibition of academic projects – integrated into a show

is Europe’s largest and the world’s second largest exporter of ceramic tiles.

ILLUSTRATION CREDITS All illustrations not credited otherwise are by the authors

9

11 12 13 15

16 17 18 23 24 27 31 32 34 35 36 37 40 42

43 44 45

46 47 49 52 53 54

55 58 61 65

66 67

Yury Asotov (2), T. Yamanashi + T. Hatori + Y. Ishihara + N. Kawashima/ NIKKEN SEKKEI (3) Simon Garcia|arqfoto.com (6) Moravské Zemské Muzeum (1) © The Trustees of the British Museum. All rights reserved (2) bpk, Berlin/Vorderasiatisches Museum, Staatliche Museen, Berlin, Germany/Art Resource, New York (3), US National Terracotta Society (6) Boston Valley Terracotta (7, both photos) Marina Sartori (9) David Saladik, MASS Design Group (1) Justin Lavallee (7) Ceràmica Cumella (9) Justin Lavallee (3) Brad Feinknopf courtesy of ikon.5 Architects (12) Toni Cumella, Ceràmica Cumella (15) Laufen Bathrooms AG (18), Jonathan Grinham (20 a–c) Kathy King (21), Buck Creek Pottery, Nelson County, VA (22) James Leynse (23), Buck Creek Pottery, Nelson County, VA (24) Kathy King (26, both photos) Márta Nagy (1 left), Jószsef Sárkány (1 right) SATRA Technology Centre (5 right), ULTRAGRIP Project (www.youtube.com/ user/itceramica/videos) (5 left) Kalinovsky (6 right) Porcelanosa (7), ITC/Javier Mira (8), Halkin Mason Photography/Shildan, Inc. (9) Mangado & Asociados (10 left), Bambalina/ Francisco Mangado (10 right), © NBK Keramik/Andreas Lechtape (11) Bas Lugthart, Maree Blok, www.bloklugthart.nl (1) Xavier Mollá (3, both photos) Paredes Pedrosa arquitectos (5, drawings), Luis Asín (5, photos), Terreal Terra Cotta (6) Gutjahr Systemtechnik GmbH (11) Terreal Terra Cotta (12), Felix Amtsberg (13, both photos) Terreal Phoniceram (14), Ludowici Roof Tile (16 top left), © Wienerberger AG: Model Alegra, Brand Koramic (16 top right), Braas GmbH (16 bottom) Barbara Krobath (17) TONDACH Gleinstätten AG (2, both photos) Carlos Fernández Piñar (4), Fireclay Tile, www.fireclaytile.com (5) © Ceracasa (1), Agrob Buchtal (2), Macieh Gutowski, Chassay+Last Architects (3), Aleix Bagué (4), Aldo Magnani (5) Chassay+Last Architects (1) Macieh Gutowski, Chassay+Last Architects (2, 6–9), Clay Perry (3–4), Shaws of Darwen (5)

68 69

70 71 72–73 74–77 78–79

80–81 82–83 85 87 88–89 90–93 94–97 98–99

100–103 104–105 106–107 108–111 112–113 114–117 119 120–123 124–125 126–129 130–133

134–135 136–139

140

145–147 150–153

154–157

158–161 162–165

© Andreas Lechtape (1) © Annette Kisling/ Sauerbruch Hutton (2), © Andreas Lechtape (3), © Sauerbruch Hutton (4), © Koyupinar/ Bayerische Staatsgemäldesammlungen (5) Eric Parry Architects (1–2) Hélène Binet (3–4), Eric Parry Architects (5), Grant Smith (6–7) Herzog & de Meuron (1, 4, 6–7), Agrob Buchtal (2, 3, 5, 8) COR asociados, Miguel Rodenas + Jesús Olivares (1–9) Eric Parry Architects (1–2, 4, 6), Dirk Lindner (3, 5), Shaws of Darwen (7) OAB (1–2), Aleix Bagué (3–6) Cretaprint (1–3), © Ceracasa (4–10) Aldo Magnani (2), Valeria Portinari (3), Enrico Geminiani (4–5) © Ted Wathen/Quadrant (2) Lily Jencks and Nathanael Dorent (1), Hufton+Crow (2–6) Manuel Herz Architects (1–10), Iwan Baan (11) Domagoj Blažević (1), 3LHD (2–3, 8–9), Damir Fabijanić (4–5, 7, 10) © Ted Wathen/Quadrant (1, 4), Beyer Blinder Belle Architects & Planners (3, 5–6) Miralles Tagliabue EMBT (1–2, 4–8, 12–13) Ceràmica Cumella (9–11) Eric Sealine (1), Artaic (2–5) Green Geometries Laboratory (1–7) Kengo Kuma and Associates (1–9) Studio Odile Decq (1–5) Kengo Kuma and Associates (1–14) Zach Seibold (2) Arturo Franco Arquitecto (1–2, 4–5, 7–9), Carlos Fernandez Piñar (3, 6, 10) Pedro Ferreira (1–8) Perkins+Will (1–2, 5, 7), Charles Davis Smith, AIA (3–4, 6, 8–10) James Carpenter Design Associates (1-2, 4, 8), Reid Freeman, James Carpenter Design Associates, © JCDA, Reid Freeman (3, 5, 9), Richard Kress, James Carpenter Design Associates, ©JCDA, Richard Kress (6), © Timothy Hursley (7) Diébédo Francis Kéré (1–10) Andalucía Team (1, 4, 7–9), Andalucía Team/Euroestudios (2), Ricardo Santonja (Solar Decathlon Europe 2012) (3, 6), Pedro M. Ugarte (Andalucía Team) (5, 10) © Mangado & Asociados (1, 3, 5–6, 9), © Roland Halbe Fotografie/2008 Mangado: Spanish Pavillon Expo Zaragoza/E (2, 10), © Decorativa-Cumella (7) T. Yamanashi + T. Hatori + Y. Ishihara + N. Kawashima / NIKKEN SEKKEI (2–10) Cloud 9 Architects (1, 7–8, 9, 11–12), Toni Cumella, Ceràmica Cumella (2-6, 10), Victor Llanos (13) Foreign Office Architects (1, 3, 8–9), Satoru Mishima (2, 5, 10), Toni Cumella, Ceràmica Cumella (4, 6–7) Peter Lynch (1–10) Nathan Craven (1–11)

166–169 Sauerbruch Hutton (1, 12),

170–171

172–175

176–179

180–183

184–187 189 191 194–195 196–197

198–199 200–201 202–203

204–205 207 208

209 210

211

212

213

214

215 216

© Wa Wettbewerbe aktuell (2), Jan Bitter (3), © Sauerbruch Hutton (5), Frank Kaltenbach, Munich (6–7, 10–11), Andreas Lechtape (8, 13–14) Boston Valley Terra Cotta (1, 3–4, 7), Government of Alberta, Ministry of Infrastructure (2, 5, 6) Barkow Leibinger (1–2, 6–8, 10), Amy Barkow (4, 5, 9), David Franck, Ostfildern (11) Pol Femenias, FEM Architecture (1–2, 4–8, 10–11), Guillem Olivares/Marc Morales (3, 9, 12) Campos Costa Arquitectos (1, 8), Daniel Malhao, Tile of Spain Awards (2, 9), Toni Cumella, Ceràmica Cumella (3–7, 14), Campos Costa Arquitectos (8, 11), Radek Brunecky, Tile of Spain Awards (12–13) Bierman Henket Architects (2, 4–5, 7–8), Joep Jacobs (3, 6, 10), Pedro Sluiter (9) Olga Mesa (1) Amanda Lee (3) Kelly Winn (1–4) Andreas Trummer (1), Stefano Andreani (2), Felix Raspall (3), © DecorativaCumella (4), Bambolina (5) Petr Krejčí (1–5) Marjan van Aubel (1–5) Heamin Kim (1), Jared Friedman (2), Jonathan Grinham (3–4), Olivier van Herpt (5–6), C. Wang, H. Cheng and A. Baquerizo (7) Rosie Kotelova (1, 5), Cat Callaghan (2), Felix Raspall (4a, b) THE SIZE (all) Laufen Bathrooms AG (High-strength porcelain), © Ceracasa Cerámica (Bioactive ceramics) Cerámicas Aparici (Slumped tile: UP), Land Porcelanico (STAR) Inalco Cerámica (Translucent porcelain), La Castellamonte Stufe-Italy (Modular ceramic stove) Daniel Becker (Berlin stove tiles), La Castellamonte Stufe-Italy (Keramos cabinets) © Ceracasa Cerámica (Inkjet-printed tiles), Emozzioni by Titanium (Physical vapor deposition) Pamesa Cerámica (Laser engraving), Fireclay Tile, www.fireclaytile.com (Recycled tiles) Vicente Sarrablo (Flexbrick), Boston Valley Terracotta (Terraclad), Terreal Terra Cotta (Shamal) Panotron AG (Panotron), Markus Bstieler (Milky Star) Terreal Terra Cotta (Acoustic Shingles), Brancós Ceramics (Acigres), Pamesa Ceramica (Material mimicry)