Bechthold, Kane, King, Ceramic Material Systems

A MATERIAL LEGACY | MATERIAL PROPERTIES | PRODUCTION PROCESSES | APPLICATIONS: INTERIORS | APPLICATIONS: EXTERIORS | LIFE CYCLE ASPECTS | SURFACE EFFECTS | PATTERNS AND AGGREGATIONS | THERMODYNAMIC SKINS | FORM CUSTOMIZATION STRATEGIES | EMERGING SYSTEMS | PRODUCTS AND TECHNOLOGIES

CER AMIC MATERIAL SYSTEMS

CERAMIC MATERIAL SYSTEMS: Far beyond their long-standing decorative and protective use, architectural ceramics have matured into material systems of great potential. Triggered by material research, design computation, and digital fabrication methods, the innovations in ceramic technology are enabling expanded applications for ceramics as multi-functional, performative systems for contemporary architecture and construction.

MARTIN BECHTHOLD

ANTHONY KANE NATHAN KING

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

MARTIN BECHTHOLD ANTHONY KANE NATHAN KING

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

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CONTENTS

8

CHAPTER 1

CERAMIC MATERIAL SYSTEMS 12

From the Origins to the 19th Century

16

18

From the 20th Century to Today

35 Jiggering

SURFACE EFFECTS

35

Firing and Kilns

18 Clay

Clay Bodies

64 Introduction

38 Post-processing

66

Surface Reliefs

39

The Wallpaper Factory, Islington,

Packaging and Distribution

North London, UK 40

CHAPTER 5

APPLICATIONS: INTERIORS 40

Adhered Tile Systems

43

Mechanically Connected Tiles

44

Sanitary Ware

46

CHAPTER 6

APPLICATIONS: EXTERIORS

21 Shrinkage

46

22

Properties of Ceramic Parts

CHAPTER 8

38 Glazing

CHAPTER 3

MATERIALS AND MATERIAL PROPERTIES 19

64

CHAPTER 2

FIRED CLAY – A MATERIAL LEGACY 12

35 Wheel-throwing

Bonded Tile Facades

68

Color Variation

Museum Brandhorst,

70

Custom Glazes

The Holburne Museum Extension,

72

Three-dimensional Surfaces

Museum der Kulturen Basel,

Munich, Germany

Bath, Somerset, UK

Switzerland 74

Pearlescent Glazes

Algueña MUCA Music Hall and Auditorium, Alicante, Spain

78

Glaze Transfers

One Eagle Place, London, UK

80

High Performance Surfaces

West Beach Promenade,

50

Ventilated Facades

22 Glazes

52

Screen Surfaces

25

Other Surface Treatments

82

Inkjet Printing

53

Acoustic Surfaces

and Coatings

La Mandarra de La Ramos,

54 Roofs 55

26

Other Outdoor Applications

28 Dry-Pressing

56

Pinnacle, Bologna, Italy

CHAPTER 7

MATERIAL FLOWS: LIFE CYCLE ASPECTS

29 Extrusion

58

Extraction-to-Production Phase

31

59

Construction and Use Phase

32 Die-cutting

60

End-of-Life Scenarios

32

Plastic Pressing

62

33

Slip Casting

Slump Forming/Slump Molding

Pamplona, Spain 84 Nano-coatings

CHAPTER 4

PRODUCTION PROCESSES

Benidorm, Spain

Life Cycle Analysis (LCA) and Material Comparisons

5

86

CHAPTER 9

118

CHAPTER 10

148

CHAPTER 11

PATTERNS AND AGGREGATIONS

THERMODYNAMIC SKINS

FORM CUSTOMIZATION STRATEGIES

86 Introduction

118 Introduction

148 Introduction

88

Complex Geometry

120

Reclaimed Tile Tectonics

150

Computer-aided Slump Molding

Pulsate, Primrose Hill,

Warehouse 8B Administrative

Villa Nurbs, Empuriabrava, Spain

Offices, Madrid, Spain

154

Volumetric Pixelization

90

Complex Assembly

124

Grão – Ceramic Pixels

Spanish Pavilion, Expo 2005,

Jewish Community Center,

Jardim Botânico Tropical,

London, UK

Mainz, Germany

Aichi, Japan

Travessa do Marta Pinto,

158

High-relief Slip-cast Surfaces

Belém/Lisbon, Portugal

Villa for an Industrialist,

94

Non-repeating Patterns

Zamet Center, Rijeka, Croatia

126

Masonic Louvers

98

Figurative Urban Mosaics

Student Services Building,

162

Low-volume Custom Extrusion

Muhammad Ali Center,

University of Texas at Dallas,

Kosemo Brick, Archie Bray

100

Curved Surface Urban Mosaics

130

Modulating Light

Santa Caterina Market,

Addition to the Israel Museum,

166

Systemic Variation

Jerusalem, Israel

Ministry of Urban Development

Louisville, Kentucky, USA

Shenzhen, China

Texas, USA

Barcelona, Spain 104

Robotic Tiling

134

Perforated Slab

Iowa State Mural,

School Library, Gando,

Ames, Iowa, USA

Foundation, Helena, Montana, USA

and Environment, Hamburg, Germany

Burkina Faso

170

Digital Reconstruction

Alberta Legislature Building

106

Tessellated Surfaces

136

Cool Cavity

Urban Guerrilla, Valencia, Spain

Patio 2.12, Andalucía Team, Solar

108

Hanging Assemblies

Decathlon Europe 2012, 2nd Prize,

Xinjin Zhi Museum,

Madrid, Spain

172

Angular Variation

Trumpf Industrial Campus

International Exposition of

176

Delineated Parallax

Zaragoza, Spain

La Riera de la Salut Remodel,

Dome Reconstruction, Edmonton, Alberta, Canada

Chengdu, China

140

Breathing Columns

112

Three-dimensional Assemblies

Spanish Pavilion at the

3Dx1, Milan, Italy

114

Structural Assemblies

Casalgrande Ceramic Cloud

144

BIO SKIN

(CCCLoud), Reggio Emilia, Italy

Sony Research and Development

180

Aggregate Production Processes

Office, Tokyo, Japan

Oceanário Addition,

Restaurant, Ditzingen, Germany

Sant Feliu de Llobregat, Spain

Lisbon, Portugal 184

Compound Surface Discretization

Museum de Fundatie Extension, Zwolle, Overijssel, The Netherlands

6

188

CHAPTER 12

EMERGING SYSTEMS

PRODUCTS AND TECHNOLOGIES

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

University Graduate School of Design 192

194

Integrated Environmental Design-

APPENDIX

Saphirkeramik Sink

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

Translucent Porcelain: Slimmker-

Thermally Active Building

Light

Envelope, The Center for

210

Modular Ceramic Stove

Architecture, Science and

211

Berlin Stove Tiles

Ecology, Rensselaer Polytechnic

211

Keramos Cabinets

Institute and Skidmore, Owings &

211

Inkjet-printed Tiles: Emotile

Merrill (SOM)

212

Physical Vapor Deposition:

196

Structural Ceramic Shell

Material Processes and Systems

213

Laser Engraving

Metallic Coatings

Group at Harvard University, Graz

213

Recycled Tiles

University of Technology

213

Preassembled Systems: Flexbrick

198

Photosensitive Blueware

214

Ceramic-Concrete Composition

Studio Glithero

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

204

Automated Material Manipulation

System: Terraclad

Acoustic Ceramics: Acoustic Shingle

216 216

Industrial Tile: Acigres Material Mimicry: Age Wood, Age Beton, Age Blend

7

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 d ­ isadvantages 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).

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

* 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.

75

40

30

Ball clay

10

15

20

30

25

35 75

Red clay 25

15

Fire clay

10

10

Flint

10

Ball clay

20

Kaolin

Nepheline syenite

20

30

35

10

10

20

10

30

10

10

15

Talc

Chart summarizing common base clay 20 Sagger clay 2 compositions.

Ball clay 15 10 20

Typical Porcelain compositions

20

40

Kaolin 10

Red clay Feldspar

10

10

10

10 30

Fire clay Georgia kaolin

35

25

Florida kaolin

10

15

English ball clay

5

10

25

5

30

40

15

25

Kentucky ball clay

15 10

30

30

25

Nepheline syenite Flint

5 15

10

Flint

Feldspar

30

20 25

20

20

25

20

20

*Parts per one hundred

Flint

10

Nepheline syenite

30

35

10 10

10

20

10 30 10 Sample Clay body compositions (A–E)*

A

B

C

10 D

15 E

Common redclay clay Stoneware

30 80

75

25 40

30

Stoneware Sagger clayclay

25

Red Ballclay clay

10

75 15

20

30

30

Ball clay Kaolin

25

15

20

20

20 40

30 10

35 5

Fire clay Feldspar

10 10

10 10

10

Flint Flint

10

35 20

Kaolin Red clay

Nepheline Fire clay syenite

15

10 10

10

20 10

10

30 30

10

Talc Georgia kaolin

35

25

25

10 5

15 30

Stoneware clay Florida kaolin

80 10

75 15

40

30 40

15

30 10

30

5

10

20 25

Ball clay ball clay Kentucky

10

15

20

Kaolin Feldspar

30

30

25

10 20

10 20

10 25

Sagger Englishclay ball clay

Red clay syenite Nepheline Flint Feldspar

10 25

5

20

20 15

30

Fire clay Georgia kaolin

35

25

Florida kaolin

10

15

English ball clay

5

10

25

5

30

40

15

25

Kentucky ball clay

15 10

30

30

25

Nepheline syenite Flint

40 20

*Parts 10 per one hundred 10

Flint

Feldspar

15

20 25

20

20

25

20

20

*Parts per one hundred

Typical Stoneware compositions

Typical Earthenware compositions

80

Stoneware clay

25

10

20

Typical Porcelain compositions Typical Earthenware compositions

Stoneware clay

30

Fire clay

20

Ball clay

Sample Clay body compositions (A–E)* A

B

C

D

E

20

20

30

35

10

10

20

10

30

10

10

15

25

30

35

25 75 25

10

15

20

10

10

80

75

40

10

15

20

30

20 30

10

Red clay Feldspar Flint

30 40

Kaolin

10

10

10

5 15

10 10 Sample Clay body compositions (A–E)* A

B

C

30 D

E

Common red clay Georgia kaolin

30 35

25

25

5

30

Stoneware clay Florida kaolin

25 10

15

35

40

15

Red clayball clay English

5

75 10

25

Ball clay ball clay Kentucky

25

15

20

20 10

20

25

30

35 20

Fire clay

Kaolin Feldspar

30

30

Fire clay syenite Nepheline

10

10

Flint Flint

10 20

20

25 10 25

10 20

10

Talc Stoneware clay

Georgia kaolin

35

25

Florida kaolin

10

15

English ball clay

5

10

80

75

10

15

40

20

30

10 10

10

10

10 30

Fire clay 25

5

30

40

15

25

Kentucky ball clay

15 10

30

30

25

Nepheline syenite

19

5 15

10

Flint

Flint

30 40

Red clay

Feldspar

15

30

Kaolin

Feldspar

20

20

Sagger clay Ball clay

15

10 per 30 10 *Parts one hundred

Nepheline syenite

Typical Stoneware compositions

Common red clay

20

Kaolin

Talc

E TypicalTypical Stoneware compositions compositions Porcelain compositions Typical TypicalEarthenware Stoneware compositions

D

Typical Porcelain compositions

C

Typical Earthenware Earthenware compositions compositions

B

Typical Stoneware compositions

A

15

Stoneware

Typical Porcelain compositions

Sample Clay body compositions (A–E)*

Typical Earthenware compositions

3

25

Terra cotta *

Diagram of common earthenware, stoneware, and porcelain clay body compositions.1

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 a ­ rchitectural 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 Common red clay Stoneware clay water systems are commonly produced in stoneware. Porcelain is a white kaolinite Red clay body, fired at the highest temperatures, and usually fully vitrified to make for very Ball clay low water absorption even without a glaze finish. Any of these basic clay bodies can Kaolin Fire clay be ­prepared as near-liquid casting slip by adding deflocculants. These are typically Flint Sample Clay body compositions (A–E)* sodium ­silicates used to dispel the electrical attraction between the clay particles, Nepheline syenite A B C D E thereby keeping the clay in a liquid, low-viscosity state.

Casting slips are used in the Talc 25 Common red clay 30 molding of geometrically complex, often parts.

Toilets Stoneware clay 35 and sinks are typical Stonewarehollow, clay 25 75 Red clay Sagger clay products manufactured using slips (see Chapter 4 for process details).

Ball clay

Darker in color

20 25

20

20

25

20

20

*Parts per one hundred

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 ­m anufacturing 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

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 e ­ nvironments 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 proces­ ses 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

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 Bau­s toffe 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

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 p ­ roducts 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 m ­ aximize 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

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. D ­ ating 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 custom-­ designed 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 R ­ ichard 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

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

100 mm

150 mm

600–900 mm

100 mm

150 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

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

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

1.800 mm

wet-molded end caps

70 mm 110 mm

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 r­ epresents 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 l­ ower, 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

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 as ­ trategy 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

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 ­S ystems 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 H ­ arvard 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

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-

The support of research in ceramic tech-

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,

building-specific 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

Starting in 1977, the Spanish ceramic tile

pages 176-179) 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-

tive knowledge about ceramic design and

ASCER also supports an international

cia Regional Government. Working with

technology. ASCER (Spanish Ceramic Tile

network of academic study groups at the

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

ceramic-related groups has positioned

sionals and industry stakeholders.

theoretically, but with the integration of

Spain’s ceramic industry as a leading center

Based in Castellón, Spain, ASCER is locat-

hands-on and industry-related activities.

of knowledge. The Spanish ceramic industry

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.

223

A MATERIAL LEGACY | MATERIAL PROPERTIES | PRODUCTION PROCESSES | APPLICATIONS: INTERIORS | APPLICATIONS: EXTERIORS | LIFE CYCLE ASPECTS | SURFACE EFFECTS | PATTERNS AND AGGREGATIONS | THERMODYNAMIC SKINS | FORM CUSTOMIZATION STRATEGIES | EMERGING SYSTEMS | PRODUCTS AND TECHNOLOGIES

CER AMIC MATERIAL SYSTEMS

CERAMIC MATERIAL SYSTEMS: Far beyond their long-standing decorative and protective use, architectural ceramics have matured into material systems of great potential. Triggered by material research, design computation, and digital fabrication methods, the innovations in ceramic technology are enabling expanded applications for ceramics as multi-functional, performative systems for contemporary architecture and construction.

MARTIN BECHTHOLD

ANTHONY KANE NATHAN KING

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

MARTIN BECHTHOLD ANTHONY KANE NATHAN KING