The Ecologies of the Building Envelope

THE ECOLOGIES OF THE BUILDING ENVELOPE A MATERIAL HISTORY AND THEORY OF ARCHITECTURAL SURFACES ALEJANDRO ZAERA-POLO / JEFFREY S. ANDERSON

Table of Contents

0.0—Envelopes: A Material and Environmental Ontology

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1.0­—Environmental Performances: The Teleology of the Envelope —026— 1.1—Transparency: The Material Tempering of a Modern Ideology —030— 1.2—Watertightness: From the Roof to the Wall —063— 1.3—Airtightness: The Breathless Envelope —084— 1.4—Insulation: The Rise of the Cellular —112— 1.5—Economics: Depth, Weight, and Logistics —134— 2.0—Components: Microevolutions in the Envelope —162— 2.1—Mullions: The Miniaturization of the Envelope —166— 2.2—Joints: Subject to Movement —188— 2.3—Membranes: Performance without Form —208— 3.0—Assembly Logics: The Tectonics of Modern Envelopes —230— 3.1—Panelized: Embodying Labor —234— 3.2—Layered: A Vertical Geology of Hidden Tectonics —264— 4.0—Assemblages: The Speciation of the Envelope —282— 4.1—Curtain Walls: Currency of the Modern Envelope —288— 4.2—Double Façades: Climate Incorporated —308— 4.3—All-Glass Envelopes: Total Vision —328— 4.4—Precast Concrete: Sin and Redemption —348— 4.5—Screens: The Making of the Mask —366— 4.6—Tensile Enclosures: From Comfort to Spectacle —380— 4.7—Media Façades: From Information to Atmosphere —396— 4.8—Vegetated Envelopes: Greenwashing —414— 4.9—Kinetic Assemblages: The Politics of Control —432— —Images Copyrights —456— —Glossary —460—

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The Ecologies of Envelopes

0.0

ENVELOPES A MATERIAL AND ENVIRONMENTAL ONTOLOGY

Envelopes: A Material and Environmental Ontology

Charles Eissen frontispice of 1753 Essai sur l’Architecture by Marc-Antoine Laugier

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The Ecologies of Envelopes

E N VELO P ES: A MATER IAL AN D EN VIRO N M ENTAL ONTOL OGY

While the façade is one of the most thoroughly theorized elements of architecture, it is also one of the most questioned since the end of the 19th century. The liberation of the façade from structural performances, facilitated by modern building technologies, may have inadvertently triggered its theoretical challenges. Within the discipline of architecture, the traditional understanding of the façade is driven by faciality and focuses primarily on semiotic and compositional operations (proportional laws and linguistic codes) which are generally deployed on the building envelope’s surface.

The hypothesis of this book is that despite the extended crisis of the façade since modernism, the building envelope remains a crucial element of architecture (in fact, perhaps one the most crucial elements), but its performance occurs through the literal and material embodiments of economic, technological, and environmental contingencies rather than through the dialectics of superficial, ornamental representation. The exponential development of building technologies across the 20th century, coupled with the large scale of modern construction, has diminished the compositional and ornamental capacities of the “façade” in favor of the material, quantitative, and technical performances of the “building envelope.” Rather than the surfacial understanding of the façade, a micro-sectional analysis has become our primary vehicle to transcend the historical constitution of the façade in the discipline of architecture.

Therefore, the aesthetic and affective performance of the envelope must become re-integrated with its associated economic, technological, cultural, and political ecologies in order to reconstruct a proper contemporary discipline of the building envelope. The theory we are aiming to construct here will—we hope—overcome the two discourses that have so far co-opted the architectural theorization of building technologies: tectonics and phenomenology. While Studies in Tectonic Culture1 remains an important reference text, as the latest significant attempt to theorize building construction, we 1. Kenneth Frampton, Studies in Tectonic Culture: The Poetics of Construction in Nineteenth and Twentieth Century Architecture (Cambridge, MA: MIT Press, 1995).

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Envelopes: A Material and Environmental Ontology

believe that the casuistic of contemporary buildings can no longer be contained within the realm of the tectonics or entirely described within a phenomenological analysis. The increasing relevance and urgency of ecological and environmental concerns and the rise of what we could describe as post-human sensibilities require a complete reframing of the theories of building technology, and the building envelope is a crucial field to explore this reconstruction.

What we are aiming here is the re-evaluation of the building envelope as a study of the processes, ecologies, and assemblages that have evolved in parallel to technical and technological development inside and outside of the field of architecture primarily during the 20th century. Materials such as glass, and assembly logics such as rainscreens or curtain walls are not representations of cultural or political concepts, but are, in themselves, literal embodiments of larger ecologies, politics, and cultures.2 The emergence, at once, of a cosmopolitical scale of performance, which addresses wider ecological concerns and a micropolitical scale of management through the building details, requires a reframing of architectural sensibilities and a shift away from the biases of the phenomenological, humanistic perspective.

Each material aspect of the contemporary façade has direct attachments to the complex ecology of economies, politics, and social structures to which it belongs. For example, the repurposing of the war machine after World War II toward the building industry, both in the United States and in Germany,3 the tendency toward the use of opaque and insulated façades after the 1973 oil crisis,4 or the use of titanium in face-sealed envelopes after the collapse of the Soviet Bloc in 1991, are all examples of the crucial links between the technologies and materials of the building envelope and their multiple ecologies.5 It is crucial that we realign the historical analysis and theories of building technologies with a new breed of architectural sensibilities that engage the wider effects of ecologies of building technology.

ENVELOPE ASSEMBLAGES AND ENVIRONMENTAL ADAPTATION

The concept of envelope assemblage, which we will use as a central methodological tool through this work, describes the incorporation of various materials to form a singular ensemble, a whole which is greater than the sum of its parts. An envelope assemblage can be interpreted as a temporary state of equilibrium within the conditions of a particular building environment (and by “environment” we mean a whole set of technical, climatic, social, economic, and political conditions affecting a building).

Central to our notion of envelope assemblages is the process of environmental adaptation. Assemblages

2. See: Alejandro Zaera-Polo, “The Politics of the Envelope, Part 1,” Log 13/14 (Fall 2008): p.25; and Alejandro ZaeraPolo, “The Politics of the Envelope, Part II,” Log 16 (Spring/ Summer 2009)p. 32 3. In relation to aluminum, see: for the US, Charlotte Muller, “The Aluminum Monopoly and the War,” Political Science Quarterly 60, No. 1 (March 1945): pp. 39-43; and, for the UK, E.C. Goldsworthy, “Light Alloys in Post-War Britain,” Journal of the Royal Society of Arts 92, No. 4663 (April 1944): pp. 230-41.

4. See Noel Uri, “The U.S. Insulation Market,” Energy Policy 6, No. 1 (March 1978): pp. 78-80.

5. For a general treatise on the construction of American power and its transformations across various socio-political platforms, see C. Wright Mills, “The Structure of Power in American Society,” British Journal of Sociology 9, No. 1 (March 1958): pp. 29-41.

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The Ecologies of Envelopes

compound the complex set of agents and forces that determine a building envelope. For example, we can refer to the degree of environmental adaptation of an envelope assemblage in order to understand its performances and how changes in these conditions may affect its design. In articulating these environmental inputs, an envelope assemblage may adopt a standard form, capable of being deployed in a wide range of projects, or a specific mode, designed for a particular situation. The range of possibilities between generic and specific, cheap and expensive, local and global sets out performances that an envelope assemblage may cater to in response to differing environmental conditions. However, a high degree of environmental adaptation in an envelope assemblage does not necessarily imply a good design: a perfect environmental adaptation is also an index of the near-total submission to predominant environmental forces and may endanger the species in the event of a sudden change in such conditions.

Excessive fitness may also become an impediment to the resilience of an envelope assemblage.

Just like natural species, envelope assemblages undergo a process of development, proliferation, and— sometimes—extinction. Unlike details, assemblages are never architectural singularities; they mobilize instead an evolving fabric of elemental and impersonal forces associated with architectural materials and their ecologies. For example, the enormous success that double façades enjoyed in Germany during the 1990s was due to a politico-ecological conflation of effects that included: the prominence of the Green movement; the fact that employment laws were passed (the law of co-determination, which made it possible for employees to require operable windows and direct sunlight in their work spaces); and a prosperous economy. A weaker economy, the pressures of space efficiency, and the availability of affordable and superior alternative technologies have considerably reduced the appetite for such doublefaçade technologies in other environments such as the United States and Asia.

1981 Mike Davies’ diagram of a futuristic computer-aided Smart Glass Pane: a thin but densely layered membrane, explained in section. Increasingly, the façade is understood less as a surface, no matter how thin it is, and more as a “thick” composition of layers with multiple performances.

There is never a singular, dominant representation attached to any envelope assemblage. Instead, there is a multiplicity of conflicting narratives and sub-narratives encompassing multiple ecologies, which may often be external to the architectural discipline. Envelope assemblages, such as precast concrete, face-sealed envelopes or media façades do not appear suddenly and evolve in a smooth historical continuum, following an inexorable path toward perfection; they do not have a progressive evolution whatsoever. They may lie dormant for decades, migrate from parallel industries, or mutate in response to new environmental pressures or simple accidents and fateful errors.

If traditional architectural history presents us with a sequence of canonical buildings and heroic architects who sequentially destabilize the pre-existing orders, we have sought here a narrative of instability punctuated by instances of convergence, when everything momentarily reaches a state of apparent

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Envelopes: A Material and Environmental Ontology

equilibrium. Our approach here dissolves these moments into a dynamic evolution of assemblages, where we might follow their rise and fall. From this perspective, non-human agents, with names such as Corning Glass, H.H. Robertson, and DuPont acquire a decisive role in the process, as the producers of entirely new and artificial materials that account for a large percentage of a contemporary building envelope’s mass. What would have become of Mies van der Rohe if he could have had access to Pilkington’s float glass before it was commercially available in the 1960s? And what fate might have befallen Frank O. Gehry without the final collapse of the Soviet Union and its effect on titanium prices?

THE EVOLUTION OF ENVELOPE ASSEMBLAGES

Buildings and their environments are perpetually changing, but they are also constrained by a limited set of possibilities, both past and future. Envelope assemblages establish and feed these constraints, without precluding their future evolution. They produce a design space;6 that is, a collection of intrinsic qualities of material components (such as tensile strength, thermal conductivity, or flexibility) as well as environmental factors (such as supply chains, markets, political economies, aesthetic trends, and regulatory frameworks), all of which, as topological field, delimit the possible evolutions of a material assemblage.

These environmental factors not only modify the actual design of material assemblages through technological development, but also their semiotic performances and the way we experience them.

Materials and material assemblages inevitably become attached to multiple narratives and representational systems over time. For example, in the early 19th century, steel windows became appreciated for their strength, slenderness and, in contrast to wooden windows, resistance to decay.7 They were immediately associated with modernist aesthetics and with the obsolescence of the traditional solid façade. While originally used for purely functional reasons, the material became imbued with “ideological merit.” –Steel windows evolved rapidly, which made them even more desirable. Yet it did not entirely guarantee the permanent success of the assemblage: the high consumption of steel during World War II led the industry to a return to wooden window frames, as steel fabricators were pressed into military production. In Italy, seriously afflicted by the League of Nations’ embargo on coal shipments to the Axis powers, the use of steel windows came to be seen as a form of treason.8 Both the signification and the experience of a façade assemblage may be dramatically affected by malfunctions in the socio-political environment as much as by its raw physical performance.

6. “Design space” is a concept proposed by Daniel Dennett to define design within an evolutionary process. Daniel Dennett, Darwin’s Dangerous Idea: Evolution and the Meanings of Life (New York: Simon and Schuster, 1995).

7. See Hentie Louw, “The Rise of the Metal Window during the Early Industrial Period in Britain, c.1750-1830,” Construction History 3 (1987): pp. 31-54. It is impossible, for example, to imagine the architectural effects in Walter Gropius’ 1913 Fagus Factory or Albert Kahn’s early 20th-century Detroit factories without monolithic walls of glass and steel.

8. See Robert Davison, “Possibilities in Postwar Techniques,” Architectural Record (May 1945): pp. 85-90. See: Nina Rappaport, “Factory,” in R. Stephen Sennott, ed., Encyclopedia of 20th-century Architecture, Vol. 1 (New York: Fitzroy Dearborn, 2004); and Sergio Poretti, “Le tecniche costruttive negli anni trenta tra modernismo e autarchia,” in 150 Anni di Costruzione Edile in Italia (Rome: Edilstampa, 1992).

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1.0

ENVIRONMENTAL PERFORMANCES THE TELEOLOGY OF THE ENVELOPE

Environmental Performances: the Teleogoly of the Envelope

Le Corbusier Le Mur Neutralisant. Possibly the first architectural enunciation of the incorporation of climate control to the facade assemblage. Drawing from the example of Northern-European traditional Kastenfenster, Le Corbusier projected a comprehensive system for entirely glazed facades.

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Envelopes: A Material and Environmental Ontology

In order to capture the complexities of the new ecologies of the building envelope, our environmental and evolutionary perspective of the subject not only requires the replacement of the old notion of “material” with the updated term “material assemblage,” it also demands the consideration of envelopes vis-à-vis the artificial reconstruction of natural elements. Water, air, heat, light, and the whole of the biosphere are now ruthlessly and comprehensively redesigned by contemporary technologies, also at play in building envelopes.

Current politics increasingly revolve around these artificial cosmologies and the phenomenology of the building envelope has to be redefined in respect to these emerging concerns.

From this perspective, we could start looking at every building as a redesign or reconfiguration of natural elements, where water cycles, air-exchange rates, heat flow, daylight intake, and biodiversity are performances that can be controlled by the geometry and materiality of the building envelope. If architecture has customarily “represented” politics, the current “politicization” of these natural elements (with which architecture has traditionally dealt with in a purely “professional” manner) offer a much more relevant field to enact political agency, within the artificial cosmologies of the Anthropocene.1 After decades of using HVAC systems to provide environmental control for buildings, it is now obvious that ventilation and insulation, two of the most critical performances that regulate the environment in buildings, appear to be dramatically affected by the material conditions of the building envelope alone.

Lighting requirements, which have been primarily controlled through artificial means in modern buildings, are once again returning to daylight provisions in the wake of increasingly stringent environmental regulations. A complex calculus of U-values, breathability, and transparency (naturally contradictory parameters) is becoming crucial to reduce the energy budget of a building envelope and, therefore, its carbon emissions—ultimately to improve its ecological performance.

1. See Bruno Latour, Politics of Nature: How to Bring the Sciences into Democracy (Cambridge, MA: Harvard University Press, 2004).

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Environmental Performances: the Teleogoly of the Envelope

For example, high-resolution sensing and modeling of airflow and atmospheric parameters are now demonstrating that the shape of a building is crucial not only to reduce downdraft and drag force in tall buildings, but also to enhance air exchange in urban canyons—a crucial factor to improving air quality in more conventional urban fabrics. There is increasing regulatory pressure to enforce a high albedo in building surfaces—in order to reflect solar radiation—and to plant green roofs and terraces in order to retain humidity on the building surface.

These regulations not only affect a building’s interior environment but reflect upon the city around in important ways, altering the local atmosphere, reducing heat island effects, or ensuring biodiversity and the continuity of wildlife corridors within urban structures. Both municipal regulations and ratings such as LEED, BREEAM, or Minergy are already setting the constraints by which the design of building envelopes will be determined through parameters of insulation, daylight transmission, or solar protection. Building regulations have recently begun to address the effects of buildings on urban climate, regulating the retention of humidity and even the provision of biodiversity and biomass on the building envelope. These parameters are becoming the real battlefield of the architectural envelope.

Most of these performances relate to the capacity of a building envelope to delimiting, distorting, or conducting the flows of natural elements, which, in the Anthropocene, have been vested with political agency. In this work we have focused on the investigation of building envelope’s performance, addressing the evolution of their technologies during the 20th century.

We have identified five relevant performances that have dictated the evolution of envelopes: transparency, insulation, airtightness, watertightness and economy.

The narratives behind the contemporary expression of many of the selected performances often overlap, feeding upon or negating one another, involving different material and cultural lineages which have become embedded in building envelope technologies.

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Environmental Performances: the Teleogoly of the Envelope

Vertical glass fins at 1978 Foster’s Sainsbury Center, Norwich, England. Seeking complete transparency, the lateral loads are taken by tempered glass elements rather than by an opaque secondary structure out of timber or metal.

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Transparency: The Material Tempering of a Modern Ideology

1.1

TRANSPARENCY: THE MATERIAL TEMPERING OF A MODERN IDEOLOGY

The quest for transparency was one of the fundamental drivers of architecture in the 20th century.

Often, it has been associated with certain political values such as openness, clarity, health, cleanliness, sincerity, democracy, and modernity. Because of these associations, transparency became a quintessential quality of modern buildings from the early 20th century. The building industry became quickly aware of people’s latent desires for transparent walls, and a range of technologies, mostly associated with the glass industry, became widely available at the end of the 19th century.

Transparency-driven technologies went through an accelerated development during the 20th century.

However, these developments not only yielded exclusively transparent elements, but a whole range of technologies and materials able to produce effects that vary from opaqueness—even reflectivity—to total transparency, ranging through many degrees of translucency. During the 20th century, we can observe technological developments aimed at achieving transparency drift toward the exploration of a wide range of effects.

While plastics appeared in the second half of the 20th century as an alternative transparent material, glass was the material around which most of the experiments in envelope transparency gravitated. Like other materials such as steel, brick, or wood, glass triggered a powerful mythology, but there is a more complex set of factors that affect the ecologies of building transparency. These include variations in taste and cultural associations as much as energy consumption and material costs. The overall transparency of the envelope is a complex equation in which these and other factors have contributed to a non-linear evolution. Materials such as glass blocks have already seen several waxings and wanings in popularity since they became available in the 1930s, whereas the quest for total transparency of the 1950s gave way to the coatings and polychromatic plastics of the 1970s. By the 1980s, smoked, colored, and mirrored glass became synonymous with office buildings and corporate towers, while today we are witnessing a return to complete transparency and the simultaneous emergence of translucency as a desirable effect. In this chapter we will try to elucidate the relations between these tendencies and associated technical, economical, and political processes.

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Environmental Performances: the Teleogoly of the Envelope

Image of a curved standing seam envelope, blurring the line between roof and façade.

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Watertightness: From the Roof to the Wall

1.2

WATERTIGHTNESS: FROM THE ROOF TO THE WALL

The building envelope has traditionally been split into two construction systems: the façade and the roof. Each of these building elements used specific technologies and developed distinct structural systems, tectonic logics, and performances. While façades had primarily defensive functions and were constructed as breathing or semi-permeable assemblages, roofs were designed to be watertight membranes, tasked with shedding bulk water away from the building’s walls and foundations.

Walls were expected to be weather resistant while allowing a certain amount of air and moisture in.

Roofs were expected not to leak, so their material constitution tended to be much more hermetic.

However, over the last century, technologies for weatherproofing façades and roofs have begun to look increasingly similar.

The disappearance of the façade’s structural duties following the emergence of steel and reinforced concrete structural skeletons, as well as the progressive takeover of mechanical ventilation as the prevalent climate control technology in buildings, triggered a period of radical transformation in the building envelope. As the façade became progressively responsible for climate control rather than for structural stability, roof and façade technologies began to merge. The façade became as insulated, waterproofed, and air-tight as the roof. While structural façade materials—for example, bricks—were always expected to provide a level of watertightness, they had a certain porosity that allowed the façade to breathe, often relying on the wall mass to evaporate capillary water penetration.

In traditional construction, watertight technologies in walls such as flashings and drip edges were mostly focused on openings, sills, jambs, and lintels, but not on the façade surface itself. While metal had been used on roofs for centuries in overlapped applications, the sudden affordability of metals during the 19th century facilitated the development of lightweight metal cladding: tried and tested roof technologies started to migrate progressively to the façade. The availability of tar paper, and later plastic membranes, in building construction triggered a progressive shift toward increasingly watertight performances in the building envelope. With the “descent” of watertight technologies from the roof to the wall, and furthermore, with the introduction of non-osmotic materials such as plastic and metal in wall and roof construction, watertightness became applied to the whole wall surface with a thin layer of material. If traditional roof and wall technologies were breathable, the

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Environmental Performances: the Teleogoly of the Envelope

introduction of non-osmotic materials across the whole wall surface effectively “sealed” the building envelope, improving upon problems associated with moisture infiltration and thermal performance, but causing collateral building problems such as in-wall condensation and sick building syndrome.

PRE-ARCHITECTURAL WATERTIGHTNESS

The watertight lineages of building envelopes derive primarily from roof technologies rather than wall assemblages. Historically, waterproofing in walls was more focused on preventing rising damp from the ground than on shedding rainwater or preventing moisture infiltration. Until the late 19th century, the wall had always been a semi-permeable membrane, allowing water to be absorbed, evaporate and dry, hopefully before reaching the interior, but dampness rising from moisture in the soil was always a concern. Thus, the first non-osmotic materials in walls were developed as horizontal layers for cutting capillary action between the wall and the ground, rather than as vertical layers for waterproofing against wind-driven rain. Alternately, roof technology has always prioritized watertightness, through a series of moisture-proofing strategies.

The physiognomy of the pitched roof was designed to use gravity, thickness, overlaps, and air chambers to prevent any water or moisture from passing through the roof. With the emergence of synthetic, non-osmotic materials, the geometrical determinations of the roof became less relevant. Watertightness could now be resolved—without relying exclusively on gravity or breathability to transmit water away from the building envelope—by relying exclusively on material performance. The roof, often referred to as the “fifth façade,” slowly became performatively one with the façade.

Waterproofing material performances may be categorized within three different technological lineages: wall thickness; sealed joints; and waterproof membranes. Material thickness uses redundancy, evaporation and gravity to prevent water ingress through the building envelope. Cavities, either intrinsic to the material, as in the spaces between straws in a thatch roof, or designed in the assemblage, as in hollow cavities formed between overlapping tiles, enable interstitial ventilation within the material to evaporate water before saturating and penetrating it. A certain amount of thickness is necessary for the material to absorb water and evaporate it before it reaches the inner side of the envelope.

The second watertight lineage is based on sealing joints between parts of the envelope. Using nonosmotic caulks—typically oil-based putties or silicone— standing seams or pressure equalizing chambers to prevent the ingress of water or humidity through the joints are examples of this technological lineage.

In the third lineage, membranes wrap the entire envelope with a layer of non-osmotic, waterproofing material. Membranes have a much longer durability than joints, and they are the most recent waterproofing technology for building envelopes, emerging only during the 20th century, first in the form of tar paper, and then in the form of plastic-based films and spun-bonded breathable membranes such as Tyvek, the latter constituting the most common type of homewrap used today.

The same three lineages of watertight technology have since migrated to the façade. Until recently, most walls were expected to accept some level of water ingress, which would dry through evaporation,

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Watertightness: From the Roof to the Wall

Caulking the hull of a ship with oakum and cotton.

not unlikely the mode in which a thatched roof works. The advantage of this is that the wall would allow the building some level of “breathability.” Breathing was sacrificed for the sake of thinness and lightness, through the replacement of thick, osmotic enclosures by thin, non-osmotic membranes or envelopes with sealed joints. The application of putties and mastics to waterproofing joints between components, or waterproofing membranes became part of this tendency toward thinness which characterizes the twentieth century façades. Today, most buildings, even panelized ones, rely on a waterproofing membrane of some sort.

The latest evolution of waterproofing technologies may be associated with what we could describe as water/air micro-entanglements, like those that can be found in standing seam assemblages or pressureequalized chambers and joints, which use the detailed geometry of building elements to prevent water ingress through superficial tension, gravity, pressure-equalization, and evaporation. Schematically, it is possible to trace the evolution of waterproofing technologies in the building envelope through a nonlinear evolutionary gestalt: that is, from a macro-geometrical technology (the “natural history” of the pitched roof, etc.), to a material technology (“industrial-strength” sealants and non-osmotic membranes), to a micro-geometrical technology (pressure equalized joints, standing seams and drip edges). The implied circularity implicates technicity, rudimentary or otherwise, in a subtle dance with both natural forces and artificial materials, the former always returning as ultimately hidden within the latter.

THE MATERIAL LINEAGE: LACQUER AND SHIPBUILDING TECHNOLOGY

Waterproofing technologies rely fundamentally on two properties of the cladding components: material and geometrical. For centuries, the hulls of boats have been waterproofed through various means. Some of the material-based technologies for transferring waterproofing joints were tested in shipbuilding technologies before being transferred to buildings. The damp-proof courses installed in Victorian walls and the lacquers of tar used in roofs and envelopes are examples of these technological transfers from “sea to land.”

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Environmental Performances: the Teleogoly of the Envelope

The most common practice for waterproofing boat hulls before the 19th century was to caulk the seams between timber planks, applied by tamping caulking material made of “cotton yarn or string, and most importantly, oakum” between the cracks and then tarring over the surface with hot pitch or lead paint.1 This practice of lacquering components with bituminous materials in order to make a waterproof seal developed in parallel in architecture, mostly applied to the base of the exterior wall, where a single course of waterproofing material was used to prevent moisture infiltration from the ground into the envelope by capillarity. Other technologies, such as soaking timbers with oil, served to prevent waterdriven decay in various building applications.2 One of the most common and arcane techniques (which remains effective to this day) was applying a layer of hot tar to the roof, which would form a monolithic, waterproof membrane. The disadvantage of these technologies was that the tar would eventually dry out and crack, requiring periodic replacement. The advantage, however, was clear: the ability to waterproof without having to resort to mechanical or geometrical manipulation of materials, which requires a higher investment in fabrication. In the mid-1950s, new non-osmotic materials like silicones and plastics— which were developed by the military industry for their lightweight and strength—were assimilated to modern construction systems. Membrane technologies constitute the latest evolution of materialbased waterproofing technologies, which enabled, for example, the flat roofs that characterized modern architecture and inaugurated a new formal freedom that was exploited extensively in the second half of the 20th century. What was crucial to the modernist shifts in the use of these technologies was that they freed the building envelope from formal constraints; constraints that had been historically determined through limits on performativity in building materials, such as the simple measure of arresting water ingress by, for example, using pitched roofs to shed the water from the roof.

COMPLEX GEOMETRIES, LIGHTNESS, AND THE ORIGINS OF WATERTIGHT METAL CLADDING

Certain types of architecture had already challenged the neat division between roof and façade technologies for several centuries. Domes, part roof, part façade, are a type of building envelope that required a waterproof cladding that was both highly durable and geometrically ductile. The use of thin metal cladding was, even during Roman times, the most common solution to shed water while adapting to geometrically complex building envelopes. Because the process of making a watertight metal envelope is fundamentally about connections between tiles or panels, different forms of overlapping and locking joints were developed. Overlapping or standing seam joints, in all their variety, produced a distinct pattern of parallel joints, which became characteristic of these cladding systems. Any joints or accidents in the surface, such as windows or intersecting volumes, required specific details, such as flashings and drip edges, to maintain its waterproofing performance. Copper was the most common metal used for overlapped or standing-seam roof assemblages in buildings since antiquity, due to its resistance to corrosion, non-osmotic nature, and relative availability. Famously, the dome of the Pantheon in Rome was clad in copper plates and copper tiles before the material was pilfered for use in other buildings.3 1. Sanford Moss, “Ship Caulkers and Their Tools,” New Bedford Whaling Museum Blog, September 8, 2009, http://whalingmuseumblog.org/2009/09/08/943/ (accessed June 6, 2016).

2. Edward Dobson, Rudiments of the Art of Building (London: J. Weale, 1849), p. 68.

3. Nnamdi Anyadike, Copper: A Material for the New Millennium (Amsterdam: Elsevier, 2002), p. 3.

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Watertightness: From the Roof to the Wall

Flat seam copper dome at the New Palace of Sanssouci, Potsdam, Germany. Copper, standing seam roof cladding is one of the roof technologies used historically for complex roofs in high-profile buildings.

Copper or lead was often used to clad highprofile buildings with complex geometries, and they therefore acquired a certain status as building materials associated with representative buildings such as churches or palaces. Watertight metal claddings were the first building technology to enable the construction of geometrically complex envelopes and sculptural forms, such as Gustave Eiffel’s 1886 Statue of Liberty or William Van Alen’s 1930 Chrysler Building spire, but they also became effective in the construction of buildings that required lightness and construction speed, such as British colonial villages in the early 1900s.

The invention of inexpensive, lightweight Corrugated Galvanized Iron (CGI) by Henry Robinson Palmer in 1829 opened up new possibilities for envelope design, particularly for inexpensive applications.4 The corrugation of the thin metal sheets provided rigidity to large sheets of material, which enabled fast, pre-fabricated construction of watertight envelopes.

Very durable and easy to prefabricate, CGI became a popular option for colonial architecture in Australia and other British Colonies. Lacking processing facilities William Van Alen 1931 Chrysler Building’s Spire was clad with and even raw materials in rural Australia, standing seam stainless steel plate, as a test of this new material which was had been recently made available to the automobile industry. prefabricated, portable housing was needed and CGI was commonly used to build watertight buildings in record time. Several manufacturers became popular in the U.K., including Samuel Hemming, H. John Manning, and J.H. Porter. In the 1830s, the “Manning Portable Colonial Cottage for Emigrants” used a simple and easy-to-construct prefabricated timber frame, which could be clad in wood or corrugated metal siding.5 Hemming’s Patent Portable House Manufactory, in Bristol, England, produced whole portable towns of CGI and installed them on the factory grounds 4. Stuart Thomson, Wrinkly Tin: The Story of Corrugated Iron in New Zealand (Wellington: Steele Roberts, 2005).

5. “Portable house proposed to be erected for the Archbishop of Sydney” (lithograph), Subinscription: “Hemming’s patent improved portable houses, sole manufactory, Clift House, Bedminster, Bristol,” Sydney Living Museums, July 2005, http:// sydneylivingmuseums.com.au/research-collections/catalogues-research-tools/pictures-catalogue (accessed June 6, 2016).

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Environmental Performances: the Teleogoly of the Envelope

A Life Magazine photograph of civilians wearing gas masks during a practice drill in London in the 1940s.

After the gas attacks of World War 1, the air itself had become a battleground, subject to weaponization.

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Airtightness: The Breathless Envelope

1.3

AIRTIGHTNESS: THE BREATHLESS ENVELOPE

According to Peter Sloterdijk, the 20th century began in April of 1915 when the German army (under the command of Fritz Haber, a Nobel laureate chemist) released its first chlorine gas attack in Ypres, France. “Classical forms of battle” were replaced with “assaults on the environmental conditions of the enemy’s life.”1 As theories of “the environment” began to take hold, the realization that air itself could be weaponized, that “the enemy’s environment, the space occupied by him, could be destroyed,”2 changed warfare forever. The potential to devastate entire armies of people at once, not through violent explosions or through high-speed projectiles, but through poisoned air, meant that war had become an impersonal battle unfolded through the radical alteration of the environment. While forms of chemical warfare had existed for centuries (with practices such as poisoning enemy water supplies or launching diseased corpses over fortifications), the use of gas in warfare underlined the crucial importance of the environment. One cannot surrender to a cloud of gas or negotiate with a molecule.

Air became a dangerous milieu subject to weaponization and a carrier of disease and pollution. Nations involved in World War I outfitted both their armies and their civilians with gas masks and protective clothing, the closest “envelope” to the human body, in order to protect them from such an attack.

Because a soldier’s objective was to make his enemy’s “continued existence impossible by his direct immersion in an unlivable milieu for a sufficiently long period of time,”3 an internal environment free of dangerous chemicals needed to be developed. A gas mask for every man, woman, and child was the only means to ensure safety from airborne pathogens. The airtight mentality that pervades modern culture through the 20th century starts here, and is driven by fear.

Such an environmental paranoia can be seen repeatedly translated to the building envelope which is periodically conceived not only as a means to generate a comfortable interior, but also as a means to fully seal out external contaminants, outside influences, foreign races, other classes, and unfamiliar ideas.

1. Peter Sloterdijk, Amy Patton, and Steve Corcoran, Terror from the Air (Los Angeles: Semiotext(e), 2009), p. 16.

2. Peter Sloterdijk, “Atmospheric politics,” in Bruno Latour and Peter Weibel, eds., Making Things Public (Cambridge, MA: MIT Press, 2005), p. 945.

3. Sloterdijk, Patton, and Corcoran, Terror from the Air, p. 16.

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Environmental Performances: the Teleogoly of the Envelope

Prior to the 20th century, airtightness was not considered a crucial performance of a wall: as long as there was structural stability and a minimum defensive performance, walls did not have to be perfectly sealed.

Air was not considered a major source of thermal conductivity, nor a major risk for the spread of disease, and no technologies were developed to block it. Airtightness became a real concern for building technology mostly as a result of the combined threat of industrial pollution, urban epidemics, and chemical warfare at the beginning of the 20th century, and architecture became often an expression of this fear.

The citizens of the developed world in the early 20th century experienced an acute episode of collective “terror from the air.”4 This led to a generalized desire for buildings—particularly those in urban contexts—to seek complete isolation from the open air, which had to be strictly filtered and, ideally, climatized. As a result of this quest for a radical split between the inside and the outside of buildings, new technical possibilities for treating air and sealing the building envelope developed very quickly: mechanical ventilation systems, synthetic membranes, and sealants, which hardly existed in the building industry before the 1950s, became prevalent in building envelope assemblages.

In some instances, the separation of interior and exterior expanded to include class and racial divisions: elevated walkway systems in downtowns during the 1960s and 1970s produced the segregation of public space and “breathable” air.

The “white flight” of this period carried citizens predominantly of white ethnicity from the city to their suburban bubble: highway systems and skywalks between parking garages and 2015 Chai Jing’s documentary “Under the Dome”was seen by 300 million people office buildings preserved the right in a week, before it was banned by the Chinese government, but it has been credited with China’s current drive to fight air pollution due to its massive impact. atmosphere in hermetically sealed tubes connecting conditioned 5 environments. The psycho-social environment in which this shift occurs is clearly conditioned by a combination of white privilege and general fear or paranoia at a mostly subconscious and collective level.

If air is a “common” element, which we all share, and connects every human being,6 buildings in the early 20th century discovered their power to delimit air, filter it, and qualify it, making it available for 4. Ibid.

5. The term white flight refers to the mid-20th century phenomena (primarily in the United States but also in other countries) in which white families moved out of racially mixed cities and into racially homogenous suburbs. This resulted from a number of factors including urban decay, the construction of

the interstate highway, desegregated schools, and racially biased renting practices. See: Encyclopedia of Race, Ethnicity, and Society, Vol. 3. ed. Richard T. Schaefer (Thousand Oaks CA: SAGE Publications, Mar 20, 2008). pp. 1395-97.

6. Naomi Klein, This Changes Everything (New York: Simon & Schuster, 2014).

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Airtightness: The Breathless Envelope

those who could afford it. Ventilation had been a past concern of architecture, but containment was a rather new interest of the 20th century. The development of air-based weapons on an industrial scale, plus the development of hermetic sealant technologies during the Space Race, produced an entirely new perception of air and atmosphere during the 20th century.

Architecture, which had never been very concerned about air became invaded by technologies of filtering, heating, and cooling, or more generally “qualifying” air. Many of the technologies developed to contain air through architecture have later developed their own pathologies, such as the infamous “sick building syndrome,” which developed in buildings built during the post-war period, where the possibility of natural ventilation had been entirely removed, and normative ventilation standards dropped below minimum requirements.7 The “breathability” of the building atmosphere has become an important question for modern buildings, particularly in light of new environmental and security risks, both real and imagined.

CAPITALISM AND AIR: THE BIRTH OF “THE ENVIRONMENT”

The word “environment,” which we commonly use to describe a physical, social, climatic, ecologic, or cultural milieu in which we are immersed has a relatively recent history. The concept of “environment” was “coined by biologist Jakob von Uexküll in 1909 in his book Umwelt und Innenwelt der Tiere.8 Described as the “biological foundations that lie at the very epicenter of the study of both communication and signification in the human [and non-human] animal,”9 Umwelt refers to all the information exchange between a living entity and its surroundings. Before the turn of the 20th century, there was no conception of “environment” as we now understand it. If anything similar existed, it was the classical notion of socio-political milieu. The development of biology and an increased awareness of the ecological impact of the Industrial Revolution at the end of the 19th century were perhaps the reasons for this newfound environmental consciousness, later to edge toward an ethics that would, in turn, infiltrate the building trades in the late-20th century. The polluting effects from the Industrial Revolution became evident already in the early 19th century, when crowded European cities were inundated with smog and waste and subject to devastating epidemics such as the 1817-1824 Cholera pandemic, and later the air-borne Spanish Flu from 1918, which infected 500 million people worldwide and decimated urban populations across the globe.

Such a casuistic triggered a variety of initiatives aimed to protect cities from the toxic effects of industrial activities and exponential urban population growth.

Under increasing pressure from the urban middle class, the first large-scale environmental protection laws came in the form of Britain’s Alkali Acts. These acts, first enacted in 1863, attempted to limit the discharge of industrial byproducts (specifically, gaseous hydrochloric acid) in the production of soda ash, which were demonstrated to cause negative effects on the health of animal and plant life.10

7. See W.J. Fisk, A.G. Mirer, and M.J. Mendell, “Quantitative Relationship of Sick Building Syndrome Symptoms with Ventilation Rates,” Indoor Air 19, No. 2 (April 2009): pp. 159-65.

8. Jakob von Uexhull, Umwelt und Innenwelt der Tiere (Berlin: J. Springer, 1921).

9. Thomas A. Sebeok, “Foreword,” in Contributions to the Doctrine of Signs (Lisse: Peter de Ridder Press, 1976), p. x.

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Environmental Performances: the Teleogoly of the Envelope

Fitting rockwool insulation between battens of a timber structure.

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Insulation: The Rise of the Cellular

1.4

INSULATION: THE RISE OF THE CELLULAR

While walls always had to protect property and provide shelter from rain and wind, the capacity of the envelope to act as a thermal barrier to provide comfort has a much shallower history. Thermal control (and to a degree, acoustic shielding) was supposed to be regulated by active systems or personal clothing. Until fairly recently, most homes in temperate or cold climates used fireplaces to fight the cold, and the hearth focalization created a gradient of thermal comfort throughout the house. The development of active systems technologies produced a shift from this gradient of temperature, radiating from the hearth, to a more homogeneous temperature distribution preserved by the envelope.

It was only when the threshold of comfort rose as a result of rising energy prices that the need for insulating performances appeared in the ecological gestalt of the building envelope. The desire for a higher level of comfort may be said to have proportionally driven the attendant higher performances of the assemblage.

Insulation is the performance most closely tied to economic ebbs and flows. While waterproofing and airtightness are generally non-negotiable performances, levels of thermal and acoustic comfort are expendable and can also be undercut in times of scarcity. As thermostats go down, both traditional and technical means for staying warm re-appear. Since the beginning of the 20th century, every economic downturn has seen a subsequent thickening of the envelope insulation, whereas times of economic prosperity have sponsored emaciated façades that use energy wastefully. Insulation and economy are so closely tied that the energy crises of the 1970s created a national shortage of insulation material in the United States as homeowners scrambled to increase the thermal resistance of their property to economize on heating. Crucially, until very recently there was no technology capable of producing visual transparency and high insulation at once, and the options remain still very limited. Therefore, insulation has inevitably been linked with opacity and all of its associated semiotics: the free-flowing, borderless, transparent space of modernism is fundamentally at odds with environmentally conscious energy-saving measures as well as with the postmodern re-cellularization of space.

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Environmental Performances: the Teleogoly of the Envelope

Eugene Peclet, a French Physicist was the first to theorize the physics of thermal transfer in his Traité de la chaleur considérée dans ses applications in 1868. He formulated the U-Value as the measure of heat transfer.

Before the systematic application of insulation layers to building envelopes, insulation occurred simply through the constituent building elements acting as thermal barriers. Vernacular construction systems, which were primarily designed to keep out rainwater and dampness, also have inherent insulating properties or thermally stabilizing performances, delivered through thermal mass. Adobe structures, mud brick, cotton or hay infill, thatched roofs, and other natural building materials prevented water infiltration through evaporation, while also providing walls and roofs with thermal mass and insulation which contributed to mitigate temperature peaks. It was not until the mid-19th century that artificial insulating materials for building construction became available as a distinct layer of the envelope assembly, mostly as a result of the development of artificial insulation materials such as rockwool or plastic foams. Traditional insulating materials—for example, felts, cork, carpets and wooden cladding—disappeared with the development of synthetic insulation, which was much easier to produce and install, and more durable.

Interestingly, materials such as cotton, hay, and sawdust have seen a recent resurgence in light of environmental consciousness and sustainable building practices.

THE VALUE OF INSULATION

Building envelopes, were always considered primarily an enclosure with structural, defensive, or representative functions. Their performances included the containment of air and protection from rain, wind, and sun, but were not driven to the blockage of thermal transfer. It was assumed that by stopping airflow between inside and outside, environmental conditions could be controlled by heating and cooling the internal space. The heat transfer through the building envelope was effectively ignored as a relevant environmental control factor. The quantification of heat transfer is a much more complicated measurement in building envelopes than air, water leakage, or structural stability, and the development of envelopes as thermal barriers was only possible after the development of heat-transfer measurement systems.

The framework for our current understanding of heat transfer and thermal conduction in building envelopes was set up in the 19th century by French physicists Jean Baptiste Joseph Fourier and Jean Claude Eugène Péclet. Fourier formalized his studies of heat and heat transfer in his 1822 publication, The Analytical Theory of Heat, wherein he revised Isaac Newton’s heat equations to recognize that 1. Kurt Rolle, Heat and Mass Transfer (New York: Cengage Learning, 2015), p. 38.

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Insulation: The Rise of the Cellular

heat “flows down a temperature gradient, or temperature differential over a distance separating the two temperatures.”1 Describing phenomena such as heat flux, temperature gradients, and thermal conductivity, Fourier’s research was expanded upon in the following years by Péclet. In 1828, Péclet introduced the k-value, a coefficient for “a body’s permeability to heat.”2 This value, currently known as the U-value, measured in watts per square meter Kelvin (W/m2K), has become the standard measure of heat transfer in building envelope design, although it would take over a century to become incorporated into building regulations. It was only with the energy consciousness which emerged with the Great Depression and peaked during World War II and the 1970’s Oil Crisis that heat transfer through building envelopes became an increasingly relevant concern. Today, the building envelope is designed to match thermal performances as defined by measurable and scientifically calculable parameters. While Péclet’s work did not affect the building industry until long after his death, he could certainly be considered one of the pioneers of modern building physics, those people who helped to understand phenomena previously only intuitively assessed by centuries of building practice. U-value has become now one of the key parameters of environmental control calculation for buildings and one of the biggest drivers of the current evolution of building envelopes.

STONE COTTON CANDY AND THE TECHNOLOGICAL LEGACY OF THE GREAT DEPRESSION

The first deliberate use of insulation in buildings was not intended to protect occupants from harsh climates but to protect them from the dangers of industrial production. It took place in the UK during the Industrial Revolution, when steam engines and furnaces became wrapped in insulation to protect workers from the intense heat radiating from industrial furnaces.3 The first artificial insulation was produced by chance in 1840 in a blast furnace in Wales owned by Edward Parry.4 Originally known as slag wool, and it was produced by firing a jet of steam at a flow of molten slag (the stone-like waste product resulting from smelting or refining metallic ores) causing beads of molten material to be expelled and form thread-like filaments of material as they cooled.5 This process was refined and blankets of material began to be sold at an industrial scale, with the same general product becoming known variously as, to name a few, mineral wool, rockwool, and stone wool.

It was not until the 1880s that mineral wool insulation was first installed in American homes. Rigid and semi-rigid board materials, under brands such as Celotex or Insulite, started their use in American housing between 1910 and 1930,6 but there was no widespread use of insulating material for residential buildings until the late 1930s. An Architectural Forum article from 1937 described the basics of 2. Matthias Fuchs, Manfred Hegger, Thomas Stark, Martin Zeumer. Energy Manual: Sustainable Architecture (Basel: Birkhauser, 2008), p. 83.

5. Ibid.

3. Richard T. Bynum, Insulation Handbook (New York: McGraw-Hill, 2001), p. 4.

6. Joanna Dowling, “Blanketing the Home: The Use of Thermal Insulation in American Housing, 1920-1945,” Association for Preservation Technology Bulletin 40, No. 1 (2009): pp. 33-39.

4. “Slag,” in Charles G. Warnford Lock, Robert Haldane, Ernest Spon, Workshop Receipts, for Manufacturers and Scientific Amateurs (London: E. & F.N. Spon, Ltd., 1909), p. 439.

7. Albert Meyer, “A Technique for Planning Complete Communities: Part 2,” Architectural Forum (February 1937): p. 140.

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2.0

COMPONENTS MICROEVOLUTIONS IN THE ENVELOPE

Components: Microevolutions in the Envelope

Kraanspoor Office Building by OTH Architecten

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Envelopes: A Material and Environmental Ontology

Building envelopes are often built from a kit of parts. These parts are obviously determined by the construction logic of the assemblages. As construction logics evolved, so did these components. If we were to apply Cuvier’s principle of correlation between parts1 to the parts of the building envelope, the analysis of a single part can reveal the nature of the species to which it belongs. The analysis of the envelope’s primary components (as subject to independent evolutionary processes) is an interesting scope within our attempt to an ontology of the building envelope.

These chapters are an attempt to look at the evolution of envelopes from the analysis of a selection of their parts. We have selected three primary components of modern envelopes—mullions, joints, and membranes—as the key components through which we might understand the evolution of the envelope’s species.

The evolution of the mullion over the last century has involved the successive incorporation of higher performative requirements of the building envelope. As a result, the contemporary mullion has evolved into a microcosm of all the environmental barriers that the envelope itself is expected to uphold. At its most basic level, a mullion is a structural element which fixes the envelope to the primary structure of a building without substantially reducing the performances of the panels that it holds in place— such as watertightness, airtightness, and acoustic insulation. Furthermore, the mullion has evolved from a single sealed joint to a pressure-equalized and thermally broken joint.

The materials that typically compose both membranes and joints have coevolved through two quite different envelope lineages. Primitive waterproofing materials, such as tar, could be used as joint sealants or infused with paper to form membranes.

Rubber could be formed into either sheets for covering large areas or durable gaskets for waterproofing paneling joints. When synthetic materials became available, the construction logics of both membranes and joints evolved with them. These materials became immediately popular with building envelope technologies: Styrofoam, vinyl cladding, silicone caulk, polyethylene vapor barriers, and elastomeric sealants for joints, such as Thiokol, appeared around the mid-20th century and were enthusiastically adopted by the industry. Their successors—silicone, spun-bound polyethylene fiber 1. Cuvier’s principle of correlation of parts states that all organs in an animal’s body are interdependent, and species’ existence relies on these interactions. For example, a species whose digestive tract is best suited to digest flesh cannot survive if the rest of the body is adapted to foraging for

plants. Thus in all species, the functional significance of each body part must be correlated to the others. George Cuvier Recherches sur les ossements fossiles de quadrupedes (Discours préliminaire) (Paris: Flammarion, 2013. Originally published in 1812).

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Components: Microevolutions in the Envelope

membranes, PTFE, and ETFE—appeared later to tackle durability issues and address other conflicts, including condensation. Increasing regulatory pressure continued to drive the evolution of these components to better environmental performances.

Much as we might consider the evolution of the eye semi-independently of a specific animal or genetic lineage of animals, we can consider the history of the mullion semiindependently of the context of any specific building or envelope assemblage. The history of the mullion involves building typologies from hot houses to storefronts, from casement windows to curtain walls. Elastomeric joints cannot be said to belong exclusively to any one assemblage. The same membranes are used in “high” and “low” architectures, now cladding both the stud walls of modest housing projects and the bespoke rainscreens of cultural compounds. Often, new types of components have their beginnings outside the field of building construction, be it storefronts, ship building, automotive, or aeronautic technologies. These beginnings are often obscured by their most successful applications in the building industry. But there is always a more complex set of agents and processes that drive the micro-evolution of building components. For example, whether we focus on the metal workers who gave rigidity to glazing profiles, the shop-front designers who started using closed-profile metal extrusions, the vernacular Scandinavian builders who foresaw pressure equalization, or the refrigerator designers who first incorporated thermal breaks in insulated metal panels, all have played a crucial role in these evolutionary processes.

Mullions, joints, and membranes all have intriguing histories, full of successes and failures through which they have come to be what they are now. Getting to know these evolutions will let us understand the different instantiations of the component as temporary moments of balance within a complex of moving forces. The contemporary development of these three envelope components has revolved around the evolution of light envelope systems and curtain walls, which generally follow a logic of large-scale panelization. These modern building systems produced unprecedented complexity at the junctures between different parts (the joints) or their substructures (the mullions), or in the development of systems able to insulate and weatherproof the entire envelope (the membranes). The tectonic gestalt of these elements follows a construction lineage that escapes the piling logics of stone buildings on which the discipline of architecture has been built and engages with frame and infill structures. The evolution of modern envelope components presents an opportunity to understand the development of material ecologies yet to be incorporated in the history of the discipline.

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Components: Microevolutions in the Envelope

Image of a typical mullion detail featuring pressure caps, thermal break, gaskets, and insulated glazing units. The mullion could be said to embody every environmental performance of the envelope in a miniaturized form. (Schucco FVS 60 CV)

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Mullions: The Minituarization of the Envelope

2.1

MULLIONS: THE MINITUARIZATION OF THE ENVELOPE

Robert Le Ricolais famously stated that “The art of structure is how and where to put holes.”1 In this way, mullions may be considered a rarefaction of the wall, the pieces that are left once we have removed all unnecessary, non-structural material. Mullions are the latent framework of the wall and appear any time we attempt its excavation. From Romanesque windows and Gothic traceries to contemporary curtain walls, mullions have appeared alongside openings in the wall, originally to shorten the span of lintels but most recently, to act as a support for infill elements against wind forces. The mullion’s ubiquitous presence as the most visible component of a curtain wall (possibly the most prevalent species of modern envelopes) establishes a parental relationship to a less-evident component—the frame. If the frame “happens” when the wall is conceived as a lattice, rather than as a solid pile of matter, the mullion is the emergence of that lattice once the originating load-bearing wall proper remains only as spectral presence.

Once the wall ceases to serve as load-bearing structure of the building, the mullion becomes the substructure, which transfers the dead and live loads of the envelope to the building’s internal structural frame. While there are some dimensional and typological similarities between the mullion and the window frame, we want to focus here on the former (and its horizontal peer, the transom) as an element carrying the structural functions of an envelope in a more or less visible manner. While the window frame has the function of mediating between the fabric of a load-bearing wall and its openings (transparent, practicable or neither), the mullion is entrusted with the structural stability of the whole wall. But there is an important similarity between the two in modern construction: both the mullion and the window frame act as weatherproofing joints. It is in that capacity that the mullion goes beyond its mere structural function to become a sort of miniature of the whole envelope, where structural and weatherproofing functions are resolved in a single element. The history of the mullion is a story of how this element progressively incorporated every advance in envelope technologies: from the use of raw metal profiles as structural elements, to the incorporation of pressure equalization, drainage channels, and de-bridging mechanisms. The exponential complexification of this element over the course of a century is the record of the progressive miniaturization of the envelope in one of its most prominent components.

1. Robert Le Ricolais, quoted in, “Structures, Implicit and Explicit, Interviews with Robert Le Ricolais,” Via 2 (1973). p. 80–109.

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Components: Microevolutions in the Envelope

A MINOR TECTONIC LINEAGE

Since Vitruvius, semi-mythical narratives have been used to explain the origin of ornamental and tectonic logics in architecture. In Marc-Antoine Laugier’s adaptation of Vitruvius’ primitive hut story, architecture is first discovered in a clearing in the woods and formed by a gathering of trees.

This ensemble forms the ground, structure, and roof around an environmentally tempered domain and an implied interiority.2 Vitruvius, on the other hand, describes how this concept formed the basis for the first tectonic logic in timber temples, which continued as a skeuomorph into ornamental logics in stone temples, with, for example, timber beams over the loggia becoming triglyphs,.3 In another story, the general concept of frame and infill was described by Gottfried Semper in his discussion of the Caribbean Hut.4 Of the four fundamental elements of Semper’s version of the Primitive Hut (hearth, roof, enclosure, and mound), the enclosure was described as a light wooden structure skinned with a woven textile. Regardless of which version of this story one may prefer, the tectonics of the Primitive Hut may be cited as the origin of a constructive lineage leading from: timber frame5 to balloon frame; balloon frame to platform frame; and, finally, platform frame to curtain wall.

As opposed to the tectonic lineage of architecture with a capital A (that is, most of the history of Western architecture, specifically in religious and institutional buildings, and based on the tectonics of piling stones), frame and infill walls have always had much humbler origins—the telltale qualities

Examples of Fachwerk walls, an arcane building technology of German origins, with different solutions for the singularities in the wall. The structural singularities of the wall become immediately translated into visual elements in the wall surface.

2. Marc-Antoine Laugier, An Essay on Architecture, trans.

Wolfgang and Anni Herrmann (Los Angeles: Hennessey & Ingalls, 1977). First published 1753.

3. Vitruvius Pollio, The Ten Books on Architecture, trans. M.H. Morgan, Herbert Langford Warren (Memphis, TN: General, 2010), p. 108.

4. Gottfried Semper, The Four Elements of Architecture and Other Writings, trans. Harry Francis Mallgrave, Wolfgang Herrman (Cambridge: Cambridge University Press, 1989).

First published 1851.

5. Early examples of vernacular timber-framing techniques include German fachwerk construction or English Tudor cottages. Both of these use a heavy timber frame infilled with other materials and usually stuccoed over.

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Mullions: The Minituarization of the Envelope

and technicity developed in association with utilitarian and domestic concerns. Frame and infill (built upon a mound and around a hearth) is an economical way to construct lightweight, non-representative, ephemeral structures. If, as in Vitruvius’ narrative, the temple is a skeuomorph of the primitive hut, the transition from the vernacular Fachwerk6 to the mullion implies an alternative lineage where the Primitive Hut, as model, foreshadows not only an iconographic transfer, but also a translation of an entire tectonic logic, one that is entirely different from the lithic tectonics of Greco-Roman architectures, or those that tend to ground the classical traditions of Architecture. This tectonic lineage implies a flexing materiality which resists bending moment rather than working primarily through compression. , upon which the One could say the frame and infill structure constitutes the tectonic lineage of the cheap, the flexible, the ephemeral, the quick, and the utilitarian. The origins of this lineage are to be found in the more modest, utilitarian crafts of glaziers, ironmongers, and carpenters, instead of the high representational codes of the sacred and institutional architectures of empires or statespower, or the law—codes that quite literally operate on a geological level, extracting large rocks, carving them, and assembling them into new artificial tectonics often representative of power and privilege. Conservatories, industrial sheds, factories, and storefronts are the otherwise unsung domains in which the technologies of the mullion grew.

SMALL-TIME TECHNOLOGIES

Façade-framing technologies today are based on a phylum of small-scale building technologies that collectively constituted the conditions for the emergence of the mullion as a prototypical component of envelopes, yet only once exterior walls were liberated from load-bearing functions. It was primarily the structural independence of the façade that triggered the development of the mullion as a standard architectural component, although frame and infill technologies, such as Fachwerk and balloon-frame construction (which maintain a structural performance), remain part of our considerations here.

The convergence of small-scale, modest crafts, originally not intended to construct a whole building, developed into a building technology destined to account for most of modern envelope construction. If the curtain wall, plus its mullion patterns, were to become the prevailing trope of modern architectures after the Second World War, associating itself with the physical representation of democracy, industrial production, transparency, and many other indexes of modernity, its origins are to be found in strictly utilitarian applications, which became significant only after the fact, unlike the symbolic tropics of Greek temples and their “heavy” tectonic lineage across pre-history. We could, then, look at curtainwall technologies as the semanticization of a group of craft- and tectonics-based lineages, all of which were originally of distinct non-signifying, utilitarian agency.

During the Industrial Revolution, the availability of inexpensive, mass-produced cast- and wrought-iron profiles, plus other metal goods, brought about new possibilities for window manufacturing. Metals were lighter, stronger, and much more resistant to decay than wood, the customary material for window frames, and it soon became a better standard for building construction. While architects and craftsmen were using iron in exuberant ornamental motifs, ironmongers and window-makers became the lay 6. German name of a wall structure made with heavy timbers infilled other materials.

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Membranes: Performance without Form

2.3

MEMBRANES: PERFORMANCE WITHOUT FORM If the confluence between two materials is the most vulnerable point in a building envelope in terms of air, water or heat infiltration, a membrane implies the elimination of the joint by covering the entire envelope with an additional layer which may protect the envelope from such infiltrations. Such a layered construction implies an alternative tectonic lineage to a joined assemblage. Although the layering of the walls with different covers goes back to arcane forms of construction, membranes constitute a technological lineage of the envelope emerging primarily from the development of synthetic, non-osmotic materials in the second half of the 20th century.

Their primary trait is their capacity to perform regardless of the design and formal qualities of the envelope. The impact of this capacity for formless performance was to have a crucial impact on architectural tectonics after the 1970’s.

Since the mid-19th century, artificial materials such as bituminous solutions, foams, and plastics have been produced industrially in liquid or sheet format and have eventually been applied to the building envelope as a wash or a wrap and often covered up by more durable quality finishes.

These materials (which modern industry was able to produce in large quantities and at a very low price) had capacities that natural materials did not have—such as a reduced porosity or low heat transfer—which made them increasingly relevant to building technologies. However, their novelty (most membrane materials did not exist before the end of the 19th century and most of them were not available to building construction before the mid-20th century) brought with them unexpected pathologies. Systemic failures resulted from incompatibilities between the newly developed membranes (such as insulation and vapor barriers if improperly installed) or the low durability of certain materials (asphalt shingles and varnishes dry out and crack over time, sheet membranes get pierced, etc.). Because of their reliance on materiality rather than envelope geometry, membrane technologies are entirely dependent on the integrity of thin sheets and lacquers, which are not always as stable as traditional building materials. If traditional architecture established very direct relationships between form and performance (for example, pitch roofs prevented pooling liquid and thus aided in waterproofing), membrane technologies are formless and defy many precepts of traditional construction. Membrane construction is essentially a-tectonic.

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Components: Microevolutions in the Envelope

A MODERN CONSTRUCTION LINEAGE

Membranes are either fluids that can be troweled on a surface, or pliable sheets, glued, stapled, or laminated to a rigid substrate or frame. The first membranes were fluids such as tar, but to make installation easier they were impregnated on paper sheets to produce tar paper, asbestos paper, and other bituminous sheets. These products first came in discrete sheet form but were later replaced by large rolls which could be cut to size, tacked to a building’s sheathing, and welded together on site with beads of liquid sealant.

Primitive membranes were used to provide waterproofing, but they were also preventing air and moisture flowing through the envelope in low-cost construction systems with lightweight walls, which did not have sufficient mass to absorb and evaporate water before it went through the wall. Industrial buildings or shacks were first to incorporate the use of tar paper or troweled waterproofing layers.

As additional performances were added to construction systems, membranes became increasingly specialized. Today it is common to have membranes for water- and air-proofing, condensation control, thermal insulation, fire resistance, and even barriers to limit the penetration of certain spectra of light or radiation.

1969 Predating the 1973 publication of their Inflatocookbook, Ant Farm’s 50”-by50” (125cm-by-125cm) Pillow was originally designed for a Japanese rock festival.

When the promoters bailed, Ant Farm kept the pillow for social experimentation.

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3.0

ASSEMBLY LOGICS THE TECTONICS OF MODERN ENVELOPES

Assembly Logics: The New Tectonics of Envelopes

Jean Prouve, Window Panel for Facade, 1952.

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Envelopes: A Material and Environmental Ontology

Prior to the mid-twentieth century, the history of architecture was almost exclusively a history about the piling of stones. Despite the fact that contemporary building envelope systems rarely use stone-piling anymore as a general assembly technique, the discipline has been shaped by the accretion of solids. Alternate modes of wall assembly, such as frame and infill construction, remained outside the classical forms of the discipline; it is only during the modern period that they were vested with architectural value. In this chapter we will focus on the tectonics of primary assembly systems of building envelopes: panelized and layered.

Panelized systems incorporate multiple performances into discrete units that can be joined to form a building envelope. Panelization is driven by production and construction logistics and determined by the logistics of labor and industrial production. The scale of envelope components was traditionally determined by human labor. For example, bricks are roughly the size of the human hand, but the increasing availability of lightweight and high performing materials—such as metal panels—challenged the scale of traditional building systems. Typically limited now by the length of a flatbed truck, the width of a human arm span, and the load manageable by two workers, contemporary panels are molded in every way by transportation and installation logistics.

Layered assemblages are built up through vertical strata and are dictated mainly by expanding the performances of the building envelope. Logistics and building performance are the primary drivers of their evolution. First, dampness was handled by deploying redundant materiality and air cavities to evaporate water.

Then thermal concerns were addressed by introducing a layer dedicated to insulation into the envelope, bringing about a new era of energy conservation and comfort. But insulation brought condensation, triggering the degradation of the envelope fabric, so once insulation became a standard in building envelopes, additional layers had to be added to avoid condensation. Many new layers have entered and exited the envelope over the last hundred years, each addressing specific issues, developing new expectations of architectural performance, and often causing unexpected problems.

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Assembly Logics: The New Tectonics of Envelopes

Panelized façade systems and sheet and membrane construction have now become the predominant species of contemporary building envelopes, incorporating not only a variety of synthetic materials that were not available before the 1950s—such as Styrofoam, Tyvek, Kalzip, and Dryvit—but also the social, political, and economic structures that constitute the contemporary fabric of the building industry. Increasingly restrictive environmental regulations, normative evolution, insurance and liabilities, unions and the organization of labor, technological evolution, and the cycling of the economy are some of the processes that are embedded in the evolution of assembly modes. However, most of these processes no longer yield tectonic evidence.

They are operated on the level of detail and often on a purely chemical level, often “under the radar”. If more traditional architecture is conventionally driven by tectonics and phenomenal effects, we assist here to a whole set of performances that do not have any handles in the classical forms of the discipline. For example, if tectonic expression is crucially driven by gravitational force, the modern assembly types for building envelopes is mostly independent from gravity, which remains in play only through the mediation of human labor. Human labor or environmental performance are not visible per se, like gravity is not visible per se, but is explicated by tectonics. To understand the emerging forms of assembly of building envelopes it is crucial to identify the mechanisms by which we can make these processes sensual, potentially resetting architectural expression through new tectonic drivers.

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Assembly Logics: The New Tectonics of Envelopes

Installation of the façade panels for the 1953 Alcoa Building in Pittsburgh by Harrison & Abramovitz. The prefabricated units included windows, insulation, and gaskets in a single piece which could be rapidly installed on site.

— 234 —

Panelized: Embodied Labor

3.1

PANELIZED: EMBODIED LABOR

A panel is a prefabricated cladding component that spans between structural or substructural members and is capable of fulfilling all environmental performances. To be more specific, the type of component we will discuss here is self-structuring, meaning that it is rigid against lateral loads and wind loads and performs weatherproofing functions, including insulation, waterproofing, and airtightness, but does not resolve primary structural functions. Panels are often fixed to the main structural elements, such as slabs or columns, but they may also require secondary structure depending on the construction system. For the purpose of this discussion, we are not considering components that do not include full weatherproofing functions, such as rainscreen cladding panels.

The main driver for panelization of building envelopes is construction efficiency. Panels have a crucial relationship to building logistics and the scalar relationship between cladding elements, human labor, and tools. Both the dimensions and the weight of the panels are fundamental considerations in panelization, both in terms of transportation and assembly logic. Transport and movement are consubstantial to paneling technology. While panelization fundamentally requires prefabrication and transportation, it also implies a more complex assembly process and the consideration of movement as intrinsic considerations in the design of the unit, therefore tolerances are a very important part of panelization systems. Earlier forms of panelization were based on the idea that an element was to be handled by one or two people only, retaining some of the logics that shaped earlier building systems such as bricklaying. But as auxiliary building construction technologies such as cranes and clamping systems evolved, panels ceased to be strictly determined by human-scale logistics.

The evolution of the panel technology accelerated significantly in the mid-twentieth century.

From monolayer panelized materials to composite and multilayer panels to multilayer panels with multiple functions, panels have evolved from being primarily driven by economy to being driven by performance. The recent evolution of these technologies is driven to address not just questions of efficiency, but also of representation. Panels have evolved to incorporate variation, not just in terms of superficial determinations, but also to enable higher complexity in the overall shape of the envelope.

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Assembly Logics: The New Tectonics of Envelopes

2000 Frank Gehry’s Experience Music Centre in Seattle is clad with a coloured stainless steel irregular tiling, which was formed on site on a preformed substructural grid.

— 264 —

Layered: A Vertical Geology of Hidden Tectonics

3.2

LAYERED: A VERTICAL GEOLOGY OF HIDDEN TECTONICS

From Alberti to Venturi and beyond, the historically constructed discipline of architecture has remained mostly oblivious of whatever happens behind the visible surface of the façade. The modernist, truthseeking honest bricks and beton brut referred to a tectonics of monolithic material which tried to reconnect the envelope surfacial aspect to its inner materiality. Despite the undeniable fact that the ongoing evolution of the envelope technologies since the beginning of the twentieth century has tended towards a vertical geology of layers, this remains inexplicably untapped for architectural theory or aesthetics. As the disciplinary discourse has been primarily driven by representation, those concerns that are not visible have been sidelined. The disregard for the sequence of layers that make up the contemporary envelope as an architectural concern stems from the architectural discipline’s hylomorphic foundation and its disdain for the material substrate of architecture. As a result, the discipline has become unable to apprehend how buildings engage in the material ecologies that constitutethe most crucial concerns of the contemporary built environment: water, air, energy, and biological cycles are now at the center of contemporary politics; yet they remain outside the concerns of the discipline.

This chapter departs from the idea that a micro-sectional analysis of the building envelope may be an adequate tool to understand its engagement with these political ecologies, and to render them into newly relevant disciplinary concerns and opportunities.

STEREOTOMY VS. SCREENS

Building envelopes may be thought of as a vertical stratification of matter that separates inside from outside. Historically, there are two basic tectonic lineages in the building envelope: a “pile” logic and a “screen” logic. While there is no univocal relationship between those two tectonic lineages and certain architectural typologies, the pile logic tended to form the more solid and “representative” buildings in primitive settlements, while the screen logic was more common to secular and non-public buildings of a more ephemeral nature. Although dependent on climate and availability of materials, these tectonic logics may have had entirely different correspondences. Walls did not necessarily evolve from thick to thin as the modernist historians made us believe. There have always been thick and thin walls, but the

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Assembly Logics: The New Tectonics of Envelopes

thick walls are the only ones that survived over time, and that is why we automatically associate them to the origins of architecture. Next to the castles, the palaces, and the churches made of piled rocks, there were always the peasant’s homes, composed of sticks and woven textiles that rotted, collapsed, and were washed away over time.

Therefore, representative architectures typically followed a piling logic formed by horizontal strata. This stereotomic logic required a certain thickness and provided buildings with a Diagram of a Roman wall construction showing rubble or kind of geological permanence. In this tectonic concrete infill behind outer layers of wedge shaped bricks. lineage, which has formed most of the historiOpus Testaceum was the most popular form of concrete construction in the Roman Empire and produced very resilient cal repository of the discipline, the envelope is and strong walls. composed of three-dimensional materials like bricks or stones, which are volumetric, dense, and self-structuring. On the contrary, in the screen tectonic lineage the layering occurs perpendicular to the surface of the wall and parallel to the force of gravity and is made with layers of mostly organic materials such as textiles or wood. Typically, every layer has a different function, sometimes structural, sometimes insulating, sometimes waterproofing, and sometimes as shading or light-controlling devices.

Unlike the piling tectonic lineage, which offers primarily structural stability, vertical layers are primarily driven towards climate control. Even within the piling tectonic lineage there was often a necessary vertical layering at play, and it is not uncommon to find examples of stone walls faced with stucco or bricks and then filled with rubble, developing already a primitive vertical tectonic.1 Paradoxically the layering function in those walls is more connected to the logistics of “decorum” than to performances such as thermal resistance or moisture protection, which prevail in contemporary examples.2 There is also evidence that medieval castles were customarily wrapped in wood, straw, and wool, though very little of it has remained.3 These treatments added a layer of comfort to the austere stone walls, “[humanizing] the huge and drafty interiors of medieval castles, providing insulation and color.”4

1. As with certain forms of Roman wall construction, including opus testaceum, in which an inner and outer face of sawtooth patterned triangular bricks held back a concrete infill. See: G. R. H. Wright, Ancient Building Technology, Vol. 3: Construction (Brill, November, 2009), p. 234.

2. There is evidence that the double wall of the Library at Ephesus in Turkey served to prevent moisture penetration. The walls themselves were not moisture proof, but by incorporating a cavity between two walls, greater moisture resistance could be achieved. See: Sir Banister Fletcher, A History of Architecture (Routledge, 1996), p. 239.

3. Tapestries, among many other forms of medieval interior finishes, served as both decoration and insulation. See: Thomas Campbell, “Tapestry” in 5000 Years of Textiles, ed.

Jennifer Harris (London, 1995), p. 188.

4. Thomas P. Campbell, Tapestry in the Renaissance: Art and Magnificence (New York: Metropolitan Museum of Art, 2002), p. 13.

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Layered: A Vertical Geology of Hidden Tectonics

Replica of the Throne Room of Dover Castle, 12th Century, England.

In the Middle Ages, carpets and timber constructed often interior architectures within the buildings to provide thermal insulation from the building fabric itself.

Throughout the history of architecture, structural and defensive elements remained, while comfort linings, often produced with timber or fabrics, decayed and disappeared, making it difficult to record the early layering of the building envelope. In the early twentieth century, the emergence of new materials and technologies, but mostly the liberation of the envelope from structural functions, produced an explosion of layered envelope species. By the 1970s there were nearly as many distinct layers in a conventional residential wall as there were performances for them to achieve: insulation, waterproofing, vapor barriers, solar filters, etc. Building regulations have evolved in respect to these performance requirements, in search of energy savings and increased comfort, and are currently the strongest drivers in the evolution of envelope assemblages.

WEAVING AND MASONRY

In Gottfried Semper’s The Four Elements of Architecture, the original tectonics of the enclosure were derived from the weaving of carpets and mats, which were primarily used on the floor. The transfer of this tactile layer —protecting the human body from the ground’s damp and cold— to the wall, represented for Semper the origin of architecture, preceding masonry and piling logics: “the use of wickerwork for setting apart one’s property, the use of mats and carpets for floor coverings and protection against heat and cold and for subdividing the spaces within a dwelling in most cases preceded by far the masonry wall, and particularly in areas favored by climate.”5 5. Gottfried Semper, The Four Elements of Architecture and Other Writings, trans. Harry Francis Mallgrave, Wolfgang Herrman (Cambridge: Cambridge University, 1989). p.103.

First published 1851.

— 267—

4.0

ASSEMBLAGES THE SPECIATION OF THE ENVELOPE

Assemblages: The Speciation of the Envelope

1862 Ernst Haeckel Radiolari drawings.

— 283—

Envelopes: A Material and Environmental Ontology

In the following chapters, we have attempted to create a taxonomy of envelope assemblages, capable of initiating a theory of the envelope that understands technologies as part of complex ecologies, analyzing their historical evolution through a series of social, economic, legal, and performative stressors. We have identified nine distinct “assemblages” that have proven to be consequential in the contemporary understanding of the envelope: curtain walls, double façades, all-glass, precast concrete, screens, tensile enclosures, media façades, vegetated envelopes, and kinetic assemblages. Each of these nine envelope assemblages are inscribed within corresponding ecologies of the building envelope.

This is a first attempt at identifying the most pertinent political, economic, and semiotic ecologies of the envelope through reference to these nine assemblages; there may be more relevant assemblages emerging in the near future, some could merge under more general categorizations, and some may fall out of relevance imminently.

This classification has therefore an ephemeral validity, as assemblages have a much more unstable nature than “materials”. Hence their theoretical interest.

What our choices here have in common is that each assemblage species represents an evolutionary path that, beyond explicating its technical prowess and economic efficiencies, involves a broader range of socio-cultural and political values.

Additionally, each one of them gravitates around a certain semiotic domain whose evolution tracks changes in the cultural environment. For example, the “fear of air” is certainly a cultural phenomenon which presides over much of the twentieth century, which has direct effect on the technologies of the building envelope.

Transparency or labor efficiency are also political questions with important effect on the design of building envelopes through the twentieth century.

Some of the building envelope species, such as curtain walls, are grounded on their ubiquity and transformative capacity. These assemblages spread through their ease of production, the standardization and exchangeability of their parts, and their ability to overcome previous economic, technical, or political paradigms. For example, the curtain wall became a powerful representation of industrial production in the twentieth century. It was composed of elements that could be exchanged across different types of envelopes and address multiple conditions. This is the reason why it has continued to develop technologically and performatively for decades.

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Assemblages: The Speciation of the Envelope

Other envelope assemblages, such as double façades, are extravagant experiments that remain in the architects’ imagination, despite their chronic failures to perform. The incompatibility of certain ideological or aesthetic agendas with the restrictions of reality is a consistent theme in the architecture of the twentieth century. Occasionally, architectural ideas or politically charged schemas surpass their obvious material limitations and develop significant popularity, often to lose favor and disappear, sometimes forever, as in the case of asbestos. The double façade appeared repeatedly over the last century in bouts of extreme optimism about the ability of envelope technology to address environmental control. The near future of this assemblage is now in doubt as cheaper, thinner, more standardized, and better performing components take larger shares of the market, perhaps with the exception of Northern European office building markets.

Still, other envelope assemblages ground their success on economies, changes in lifestyle, or specific technological advances, such as all-glass environments or media façades. For example, the emergence of consumer society coincided with the development of glazing industries and the production of increasingly large and strong panes of glass, allowing goods to be simultaneously protected and put on display.

New glass technologies were then able to produce fully glazed environments, and they were immediately taken up as a kind of “branded envelope” for commercial ventures.

Likewise, media façades became an embodiment of the electrification of society in the early twentieth century, and their components have run parallel to advances in lighting technology. Due to changes in lighting technologies and altering economic and political conditions relating to energy usage, incandescent bulbs will never be used to animate a media façade again. The evolution of these envelopes demonstrates the environmental forces that drove the architectural decisions that shaped them.

Every one of the technological developments, economic contingencies, or sociopolitical environments through which these assemblages have grown has had and will continue to have a crucial effect over their future evolutions. The ecologies of the envelope, as presented through different envelope assemblages—or species of the envelope—are entangled with the performances, components, and assembly types that we have elaborated in previous chapters. These stories, lineages, and projections are meant to be complementary—and often speculative—forms of analysis, as no single historical trajectory or mode of analysis is sufficient to fully encapsulate the ecologies of the envelope.

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Envelopes: A Material and Environmental Ontology

CURTAIN WALLS 2020

DOUBLE FACADES

ALL-GLASS ENVELOPES

CAST STONE

COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-

Apple Cube 2.0

2010

Translucent Concrete

2015

2000

Apple Cube

Smart Glass

2005

Photolithography

-FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--F

-9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11-

-KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROT

1995 1990

German Worker's Rights

-COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--C

Corporate Double Facade

1985

Spider Joints

-FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERL Owens Corning Bankruptcy

1980

Quartz Aggregates Become Popular

-CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL

GFRC

-REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMIC

Double Envelope House

First Structural Silicone Glazing System

-ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISI

1975

-OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS

1970

Romney and HUD

Large Panel System

Trombe Wall

EPDM Membranes

Cold Rolled and Stainless Steel

-NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--

-MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968-

Total Vision System Float Glass

Float Glass

1965

Fair Housing Act

-CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--

1960 1955

Extruded Aluminum Mullions

-BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN

Ceramic Fritting

K-7

-SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPU

-CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOL

1950

Nikita Khrushchev

Pilkington Process

Pilkington Process Silicone

Silicone

Extruded Aluminum for Aircraft Frames

-KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR

-ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CON

1945 1940

Silicone for Electrical Insulation

-WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 E

-WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS-

1935 1930

Mur Neutralisant

Russian Worker's Clubs

-THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE N

-STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARK

1925

-STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN

Corbusier Experiments

1920

-WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI

1915

-GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATI

Laminated Safety Glass Drawn Plate Glass

-WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS Glasarchitektur

1910

Glasarchitektur

Drawn Flat Glass

-REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHIN

Pre-Cast Concrete

Tempered Glass

1900

Air Conditioning

Liverpool Precast Panels

Fourcault Process

Fourcault Process Steiff

Tempered Glass Laminated Safety Glass

1905 1895

Glass Block

Early Aluminum

1890

Machine Rolled Glass

-COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--CO

-TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC

1885

Bayer Process Hall-Heroult Process

Bayer Process Hall-Heroult Process

1880 1875 1870 1865 1860 1855

Bessemer steel

-EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATIO

Cast Plate Glass

1850

Cast Plate Glass

-BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCES

-THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EX

Glass Tax Abolished

1840 1835 1835

Hot Dip Galvanizing

— 286 —

Glass Tax Abolished

Glass Tax Abolished

Coade Stone / Other Artificial Stones

1845 Cast and Wrought Iron

Diagram representing the evolution of various envelope species over the last two centuries as a result of environmental stressors such as wars and the incorporation of new technologies such as float glass.

Assemblages: The Speciation of the Envelope

SCREEN ASSEMBLAGES

TENSILE ENCLOSURES

MEDIA FACADES

VEGETATED ENVELOPES

KINETIC ASSEMBLAGES 2020

Du Pont Hypalon Plant Closes PVC Coated Fabric Resurgence

Autonomous Facades

-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--COVID-19--V

2015 2010 2005

DIY Vertical Gardens

iPhone

2000

Vertical Gardens Popularized

Printed ETFE Foil

FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS--FINANCIAL CRISIS

Blue and White LED's

--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11--9/11

TOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL--KYOTO PROTOCOL Toyota Prius Autonomous Facades

Ethernet transmission jumps to 100 Mbit/s

1995 1990

DMX Control System

Vertical Garden Experiments

COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR--COLLAPSE OF USSR

World Wide Web

Titanium Price Drops OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL LIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL OF THE BERLIN WALL--FALL

1985

Stone Veneer Rainscreens

ETFE Foil

L--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL--CHERNOBYL

Mobile Phone

1980

CS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS--REAGANOMICS

Green Over Grey

IS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS--ENERGY CRISIS Home Computer

Toxic Substances Control Act National Energy Act

1975

Metal Screens

PVDF Coatings

S--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS--OIL CRISIS

1970

-NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK--NIXON SHOCK

EPA Emissions Standards Environmental Protection Agency

Ventilated Cavity Walls

Osaka World Expo

1965

Brutalist Greening

PTFE Coated Glass Fabric Post War Radomes Neoprene Coated Fabrics PVC Coated Polyester Fabric Hypalon Coated Fabrics Commercialized

--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968--MAY 1968

Pressure Equalization Theory

First LED's

-CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT--CIVIL RIGHTS ACT

1960

N WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT--BERLIN WALL BUILT

1955

Manual Control Machine Facades

UTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1--SPUTNIK 1

Silicone Transistor

LUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION--CUBAN REVOLUTION

1950

R--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR--KOREAN WAR

NFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT--ARAB-ISRAELI CONFLICT

1945

U.S. Synt Rubber Program Hypalon Wartime Dvtment

1940

Flourescent Lamp

PTFE Invented

ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS--WW2 ENDS

--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS--WW2 BEGINS Hydroponics Patented

1935

Nylon Invented

FHA Vapor Barriers

1930

Automation of the Home

NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL--THE NEW DEAL

Neoprene Invented MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH KET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK MARKET CRASH--STOCK

1925

N OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE--STALIN IN OFFICE

Gas-Filled Tungsten Filament Lamp

1920

I ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS--WWI ENDS

1915

IVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY--GENERAL RELATIVITY

S--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS--WWI BEGINS PVC Invented

1910

NA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST--REPUBLIC OF CHINA EST

Model T Ford

1905 1900 1895

OLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION--COLUMBIAN EXPOSITION

1890

C MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR--TESLA AC MOTOR

First Automobile

Incandescent Light Bulbs

Bayer Process Hall-Heroult Process

1885 1880 1875

First Electric Elevator

Celluloid Invented

1870 1865

ON PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION--EMANCIPATION PROCLAMATION

1860 1855

SS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMERParkesine PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS--BESSEMER PROCESS Invented

1850

XHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION--THE GREAT EXHIBITION

1845 1840 Vernacular Rainscreens

1835 1835

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Assemblages: The Speciation of the Envelope

The 1951 Lake Shore Drive Apartments in Chicago, Illinois by Mies van der Rohe, under construction. The image shows the skeletal frame of the structure and curtain wall being put in place before glass panels are installed.

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Curtain Walls: Currency of the Modern Envelope

4.1

CURTAIN WALLS: CURRENCY OF THE MODERN ENVELOPE

The curtain wall is the epitome of the modern façade and is widely identified with aspirations of transparency, mobility, lightness, and efficiency. As perhaps the most potent symbol of modernity in architecture, the curtain wall is typically associated with an ambition for total transparency and spatial continuity. However, the real driver behind this assemblage is a pragmatic force: the success of the curtain wall was determined by its capacity to replace long-dominant, heavy-masonry construction techniques with an equally universal façade system capable of entirely reconstituting the built environment. This transformation first took the form of a skeleton structure with a lightweight skin, a tectonic system that sought not only to modernize construction logics but also to unify the envelope into a transparent whole.

BRAVE, NEW, AND ARTIFICIAL

The typical curtain wall is assembled with two of the most artificial building materials ever produced by mankind: metals and glass.1 While both of these sets of materials have very old ancestors, their modern manifestations require very energy-intensive production methods that were not possible before the Industrial Revolution and the availability of steel. Steel, one of the most important metals for curtain wall applications, is made from iron ore and carbon through the Bessemer process. The invention of the Bessemer converter, a machine patented in 1856 that blew cold air through molten iron, facilitated the first inexpensive industrial process for the mass production of steel in the nineteenth century. Aluminum, the metal of choice for more evolved curtain walls, is manufactured from bauxite ore via the Bayer and the Hall-Héroult processes, a technique developed at the end of the nineteenth century that involves a “highly energy intensive” electrolyzing bath.2 It was the industrial development of the latter and increasingly lower energy prices that helped drop aluminum from the status of precious metal to common

1. See R. Michael Rostron, Light Cladding of Buildings (London: The Architectural Press, 1964), pp. 43-57.

2. “Aluminum and Aluminum Alloys” in Materials Handbook: A Concise Desktop Reference. By François Cardarelli.p. 47. Springer Science & Business Media, Nov 11, 2013.

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Assemblages: The Speciation of the Envelope

building material in the mid-to-late twentieth century. Likewise, the ability to produce large panes of inexpensive, clear glass was only possible through large scale ovens capable of melting down silica, sand, soda, and ground lime. Sir Alastair Pilkington revolutionized the production of glass when he first developed float glass technology in the late 1950s.3 Float glass, the most common glass for architectural applications today, is formed on a river of molten tin, which is another heavily enerA Bessemer converter to produce steel on a large scale. It was the gy-intensive process. The residual environinvention of the Bessemer process in 1856 that allowed the construction systems to rely on steel as a construction material. mental impact of all of these processes is well documented and includes particularly high levels of embodied energy, especially in the case of non-recycled aluminum.4 The technology that enabled the paradigmatic curtain-wall architecture of the twentieth century was developed in energy and cost intensive blast furnaces, not on city streets or in the imagination of the architects.

THE PRODUCTION OF TRANSPARENCY

Rather than the “optimization of transparency,” the development of curtain wall technology was primarily driven toward the effective mass production of transparency. Thus at the core of curtain wall aesthetics is the expression of industrial production. Joseph Paxton’s 1851 Crystal Palace in London was an iconic example of this association between industrial culture and repetitive patterns with its huge envelope featuring glass walls that were suspended from identical, prefabricated elements. Delivered and assembled as a kit of parts, the building’s thousands of identical glass units were installed in only five months.5 The ridge-and-furrow glass roof of Paxton’s Crystal Palace covered 28,000 square feet and a team of eighty glaziers installed the roof glass panes at a rate of 18,000 per week.6 Paxton’s adaptation of greenhouse technology enabled the efficient delivery of the modern, globalized, transparent, and democratic world, welcoming visitors into a world of clarity, lightness, and industrial rigor. The Crystal Palace was an ideal embodiment of modern, capitalist ideology, and became easily adopted as its architectural representation, which was to become universally embraced by the middle of the twentieth century, once the curtain wall had become a canonical form of modern architecture.

3. Sir Alastair Pilkington revolutionized the production of glass when he first developed float glass technology in the late 1950s. See Scott Murray, Contemporary Curtain Wall Architecture (New York: Princeton Architectural Press, 2009), p. 70.

4. Muhammad Asif, Alan Davidson, and Tariq Muneer, “Embodied Energy Analysis of Aluminium-clad Windows,” Building Services Engineering Research & Technology 22, No. 3 (2001): pp. 195-99.

5. See: John McKean, Crystal Palace: Joseph Paxton and Charles Fox (London: Phaidon Press, 1994), pp. 22-23; and “History of the Crystal Palace (Part 1),” Crystal Palace Foundation, n.d., http://www.crystalpalacefoundation.org. uk/history/history-of-the-crystal-palace-part-1, accessed September 12, 2014.

6. John McKean, Crystal Palace: Joseph Paxton and Charles Fox (London: Phaidon Press, 1994), pp. 22-23.

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Curtain Walls: Currency of the Modern Envelope

Pilkington’s Patent for Float Glass production, 1959. The impact in the construction industry was immediae and profound. It remains the standard system of glass production today.

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The interior of the double façade in the 1997 City Gate building in Düsseldorf, Germany.

This façade permits employees to access a shared ventilation space within the wall cavity, allowing them to open their office windows while keeping the exterior envelope mostly sealed.

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Double Façades: Climate Incorporated

4.2

DOUBLE FAÇADES: CLIMATE INCORPORATED

Double-façade assemblages are designed around glass’s capacity to serve as a trap for infrared radiation.

A nested set of glass curtain walls with an air space in-between produces a micro-atmosphere that insulates while simultaneously enabling maximum daylight availability and transparency. First used in cold climates, where there was a need for maximum insulation and maximum daylight, the double façade was dreamed to become a global technology that has progressively become locally specific. From Le Corbusier’s Mur Neutralisant to the Trombe Wall, the double-façade envelope became one of the beacons of passive-building technologies world-wide. However, the revelation of its relatively large costs in materials, maintenance, and lettable space has now weakened its strength as an envelope species. It seems now that this assemblage’s chances at survival relies on its capacity to incorporate sun-shading louvers, to act as a pressure equalizer that allows natural ventilation in high-rise buildings, or through its evolution toward expansion and occupation, generating distinct programmable zones of thermal performance within the doubled envelope itself.

ARTIFICIAL MICROCLIMATES

The possibility of using glass sheets to generate climatically active environments dates back to the Romans: according to an account by Pliny the Elder, Emperor Tiberius was said to have enjoyed a particular type of cucumber all year round thanks to the use of a mobile form of greenhouse.1 Until more advanced technology would allow large expanses of clear glass to be produced, greenhouses often used mechanical means to regulate climate, either with mobile planters, operable opaque envelopes, or stove and furnace heating systems similar to those of the Roman hypocaust.

For example, Salomon de Caus’ 1619 design for a temporary winter orangery featured a structure to be built around an orange grove, trapping air to create an artificial environment. In 1626, Duke Farnese’s 1. See: Pliny the Elder, “The Nature and Cultivation of Flax, and an Account of Various Garden Plants,” in Pliny the Elder, The Natural History, ed. and trans. J. Bostock,

H.T. Riley (London: H.G. Bohn, 1855), Book XIX, Ch. 23.

Written circa 77 AD.

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Assemblages: The Speciation of the Envelope

orange trees were surrounded by a similar permanent framework. During the winter months, the roof would be un-tiled and retiled daily, an extremely labor-intensive process. In John Evelyn’s 1691 design for a greenhouse, a stove and furnace heating system kept the interior at a stable temperature during colder months.

Thomas Jenkins’ method of raising pineapples, from J C Loudon’s “The modes of raising pineapples’ (1822). Loudon became interested in ancient uses of glass for agricultural purposes, and their potential application to climatize buildings.

With seventeenth-century glass-making technology came the birth of the modern greenhouse and conservatory, an assemblage whose ability to regulate climate depended passively on material properties and the logic of their assembly rather than active mechanical operations.

The arrival of large-scale glassmaking technologies coincides with the Enlightenment, and there was an association between the transparent qualities of glass and the liberation from the obscurity and superstition of the Ancien Régime. While this assertion loads glass assemblages with ideological content, the double façade’s relevance as an envelope assemblage emerges not merely from its use of clear glass, but from its capacity to incorporate air, climate, and even nature into the façade. While the association with scientific clarity dates back to the seventeeth century, it would not be until the early nineteenth century that climate was incorporated directly into the façade.

SHIPBUILDING TECHNOLOGIES AND COLD WEATHER

The double façade’s genesis may be traced to two phenomena: first, the greenhouse effect and its capacity to capture solar radiation through the use of glass; and second, the ability of an air space to act as thermal insulation. In the eighteenth century, the increasing availability of glass and its use as a shipbuilding material facilitated a transfer of technology in maritime cities such as Coruña and Ferrol in Northwest Spain. Plate glass, manufactured in the Royal Glass Factory in the La Granja de San Ildefonso, a factory promoted by enlightened Spanish royals, was sent to Ferrol for glazing the sterns of large Spanish galleons as early as the mid-eighteenth century. Mimicking shipbuilding construction, the locals soon realized that glass was able to retain solar radiation for the benefit of domestic environments. The ability of this assemblage of glass, air, and masonry to act as a climatic device quickly became apparent and triggered a systematic application, first in the neighborhood of Magdalena in Ferrol, and then in Coruña and Pontedeume, neighboring cities with similar climates and similar attachments to naval technologies. That is how the Galician gallery originated as a local façade typology that produced systematic glass enclosures of exterior balconies, using wood-framed glass sheets wrapped around stone masonry buildings.

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Double Façades: Climate Incorporated

Masonry building in Ferrol, Spain with balconies overclad in wood and glass to create sun rooms. The ability of glass to trap heat was exploited in the shipbuilding cities of Galicia during the 18th century.

KASTENFENSTER

In Central Europe, the conflicting demands of increased daylight (requiring larger windows) and welltempered environments (requiring more insulation) drove the evolution of the Kastenfenster or double window. An air chamber between two windows (often with one set pivoting inward and one set pivoting outward) performed both as a thermal insulator for large window openings and as a heat collector.2 In prosperous cities such as Vienna, Prague, and Berlin, the Kastenfenster became a standard façade assemblage applied systematically in urban residences. The double window allowed a degree of control over the thermal and optical performance of the window. The window could be left open to permit ventilation or closed for maximum thermal performance while permitting ample light to penetrate the envelope. Occasionally these traditional windows would include a layer of shutters, tripling the window and providing even more privacy and control over solar radiation and heat gain while limiting exposure of the private life, an important factor in dense urban environments. This legacy of control through layers would later evolve into a variety of double envelope species, which became particularly prevalent in Germany in the 1990s, sometimes incorporating multiple layers of operability and incorporating shading elements into the façade. With the current strengthening of environmental regulations, Northern European buildings are increasingly resorting to double façades in order to be able to provide variable sun-shading while being able to protect the louvers from wind pressure. The increasing regulatory pressure to enable buildings with openable windows also requires the installation of a pressure equalizing glass layer, which shields openable windows from wind-driven rain.

2. Hermann Klos, “Kastenfenster,” in Das Fensterim 20.

Jahrundert (Baden-Wurttemberg: Rottweil, 2010), pp. 3-37.

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Assemblages: The Speciation of the Envelope

The first version of the 5th Avenue Apple Store in New York City, built in 2006 by Bohlin Cywinski Jackson and engineered by Tim McFarlane initiated a very successful trend toward all-glass envelopes. This building would be renovated with new technologies in 2011, greatly reducing the number of glass panels used in the envelope and structure.

— 328 —

All-Glass Envelopes: Total Vision

4.3

ALL-GLASS ENVELOPES: TOTAL VISION

While the myth of the transparent envelope ran deep in modernist ideology and vested fascination in the public imagination thereafter, the search for a totally transparent envelope became a rather limited experiment rather than a ubiquitous technology of mass-production. All-glass technologies are sophisticated, expensive, and, while accessible to the popular imagination, have always remained rather exclusive. Taking to the limit the problem of transparency, all-glass technologies aim to erase the visual presence of the envelope or to visually extend the interior outward toward the outside. While the all-glass façade has only a few components (glass, clips, wires, sealant, and bolts), they feature some of the most sophisticated façade engineering because of the precision they require to be built. The availability of increasingly larger panes of glass has demanded new strengthening techniques, as well as new methods for transport and installation. Additionally, the erasure of the mullion has developed new structural solutions such as spider joints and advanced structural silicones that are sufficiently resilient to withstand significant deflections and the temperature differentials inherent to the all-glass assemblage.

VICTORIAN GREENHOUSES

Architectures of total transparency appear in cycles, often immediately following the invention of new manufacturing techniques or energy price downward fluctuations. The first all-glass structures were built in England in the early nineteeth century at the height of the Industrial Revolution. A trend of “ecological colonialism” drove the desire to cultivate non-native plants on the grounds of wealthy estates, which, because of the different climatic conditions from source to new territory, required the transmission of not only seeds and plants, but also of whole environments.1 Victorian greenhouses were, perhaps, the first architectures to exploit the heat-capturing properties of glass, producing localized tropical environments within the temperate English climate. Early all-glass enclosures were also made possible by the abolition of the Glass Excise Tax in 1845 in the United Kingdom, the development of metallic structures, and improvements in the quality of plate glass. Hothouse designer John Claudius Loudon developed the structural technology he described as “stressed-skin,”2 which enabled him to minimize the presence of 1. Alfred W. Crosby, Ecological Imperialism: The Biological Expansion of Europe, 900-1900 (Cambridge: Cambridge University Press, 1986).

2. Brent Richards, Dennis Gilbert (photographs), New Glass Architecture (New Haven, CT: Yale University Press, 2006), p. 11.

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Assemblages: The Speciation of the Envelope

A precast concrete façade panel being hoisted into place in London’s St. Catherine’s Dock. In contrast to the lightweight curtain wall, concrete panels are an extremely heavy construction technology.

— 348 —

Cast Stone: Sin and Redemption

4.4

CAST STONE: SIN AND REDEMPTION

The technology behind precast concrete effectively grants the ability to artificially reconstitute stone, the very material essence of architecture, into a multiplicity of unnatural forms and qualities. Perhaps attempting to redeem itself from this immoral act, the history of precast concrete involves a succession of associations with a variety of social programs and humanitarian endeavors, most of which inevitably ended in failure, and none of which resulted in a convincing alibi. Ultimately, precast concrete has only excelled through artistic performance. Only its most artistic applications seem to have finally succeeded in solidifying this as a relevant contemporary technology.

TAMPERING WITH THE SACRED

Stones have always been thought to possess a sacred aura. From the megalithic structures in northeastern Europe, to the Black Stone in Mecca, to the Mo’ai on Easter Island, stones have been vested with apparent transcendental powers, a subliminal archaism surviving to this day. Stones have long been understood as the product of mysterious cosmic processes and have been imbued with special significance. Hegel described the origin of symbolic architecture in stones, phallic columns, and obelisks.1 Strong, durable, and able to be sculpted into many forms, stone has been called upon to perform in almost all consequential human-built endeavors.

The Romans were the first to subvert natural stone through the invention of opus caementicium, a hydraulic cement that could be poured into any form and would set into a stone-like material.2 Used extensively during the Late Republic for architectural and infrastructural work, it was employed most notably in the dome of the Pantheon. This example illustrated the structural and sculptural potential of this material and marked the onset of concrete’s paradoxical history: this material has been called on to produce both the most extravagant forms of decoration and the most sober forms of social housing and infrastructure.

1. George W. F. Hegel, T. M. Knox, trans., “Independent or Symbolic Architecture,” in Aesthetics, Lectures on Fine Art, Vol. 2 (Oxford: Clarendon Press, 1974), pp. 635-659.

2. Carmelo G. Malacrino, “Construction Techniques in the Roman World,” in Constructing the Ancient World: Architectural Techniques of the Greeks and Romans (Getty Publications, 2010), p. 123.

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Assemblages: The Speciation of the Envelope

A section of the Roman city-wall of Empuries, Spain. 1st century BCE. The base of the wall was made using calcareous rock while the upper portion is built with Roman concrete (opus caementicium).

After the fall of the Roman Empire, artificial stone technology was, for the most part, lost. In 1756, John Smeaton, tasked with rebuilding the Eddystone Lighthouse in Devonshire, England, and needing a binding material that could cure in wet conditions, invented hydraulic lime. This hydraulic-curing, cementitious material, commonly known as Portland Cement, is still the primary cement in use well into the twenty-first century—and in fact the single most widely used material in the world.3 Having completed nine courses of the lighthouse’s base, work ceased for over half a year in 1785. After returning to work, Smeaton and his workers found that the “cement seemed to have become as hard as the stone itself, from which, indeed, it was scarcely distinguishable.”4 Some 120 years after Smeaton’s intervention, cracks began forming in the rock on which the tower was built. The upper portion of the tower was rebuilt as a monument in Plymouth Hoe, while the interlocked and cemented layers of granite blocks that made up Smeaton’s base stands to this day.5 Consequently, and as a testament to the lasting strength of Smeaton’s invention, the base of his tower remains undisturbed as a monument to his contribution to building technology.

Cementitious “ hydraulic-lime” was used to weld together the dove-tailed granite stones comprising John Smeaton’s lighthouse foundation from 1756. The foundation was so strong that it has withstood both the forces of nature and a demolition campaign.

3. James Mitchel Crow, The Concrete Conundrum, Chemistry World (2008), p. 62. http://www.rsc.org/images/Construction_tcm18-114530.pdf

4. T. Nelson and Sons, The Story of John Smeaton and the Eddystone Lighthouse (London, 1876), p. 36.

5. Leo Marriott, Lighthouses (Globe Pequot, 2003), p. 42.

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Cast Stone: Sin and Redemption

EARLY PRECAST

The entrance to the AA in Bedford Sq. London is decorated with Coade Stone dowels, built in the 1770s.

Coade Stone is a stone-like fired ceramic which was one of the first examples of mass produced precast stone and was used primarily for ornamental details.

In the 1770s, Eleanor Coade and her daughter began to manufacture Coade stone, a kind of artificial, stone-like fired ceramic, which was supplied in molded blocks for stone plaques and string courses.

Stone, once a material to be carved laboriously into details for the most sacred architectures, could now be molded in standard forms into ornamental elements.6 Coade’s stone substitute was enthusiastically embraced by the leading architects in Britain at the time, such as Robert Adam, John Nash, and Sir John Soane. During the 1910s, cast stone was developed extensively as a cheap substitute for expensive stone carving. Molds allowed for the repetition of classical ornamentation in department stores and institutional buildings in Europe and the United States, proliferating fake classical details and Art Deco motifs.

But after this frivolous episode, in the early twentieth century, John Alexander Brodie, a Liverpool engineer, tried to redeem reconstituted stone from its ornamental tendencies through the development of a system for casting concrete panels for both industrial and residential use. In 1905, Brodie constructed the Eldon Street Apartments in Liverpool out of prefabricated concrete slabs, one of the first examples of comprehensive precast concrete building construction.7 However, Brodie’s precast concrete housing invention did not become popular, and this building technology laid dormant for several decades.

John Alexander Brodie built the Eldon Street Tenements in Liverpool in 1906, the first example of precast concrete applied to social housing.

6. Allison Kelly, “Coade, Eleanor (1733-1821), Manufacturer of Artificial Stone,” Oxford Dictionary of National Biography, 2004, http://www.oxforddnb.com/ index/101037296/Eleanor-Coade.

7. Florian Urban, “Social Reform, State Control, and the Origins of Mass Housing,” in Tower and Slab: Histories of Global Mass Housing (Routledge, Jul 3, 2013).

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Assemblages: The Speciation of the Envelope

The façade of Frank O. Gehry’s Experience Music Project under construction in 2000. The many layers of the complex, curved geometry are on full display in this view.

— 366 —

Screens: The Making of the Mask

4.5

SCREENS: THE MAKING OF THE MASK

Multi-layered façades were developed to improve the environmental performance of the envelope by making it hollow or porous. Capable of expressing a wide range of functionalities, from cavity walls to rainscreens to solar screens, these layered assemblages have recently become popular in the practice, but have not been yet incorporated to the discipline, which has been built on the idea of the façade as a solid element with perforations. The façade as an assemblage of layers—a vertical “geology”—has become lately the dominant model of contemporary envelope design. Functional reasons such as ventilation, pressure equalization, and solar shading were the original reasons for these assemblages to emerge. Having evolved into a popular contemporary assemblage, function has been left behind in favor of expression.

PLAIN BAD WEATHER

Rainscreens have vernacular genetics. The earliest surviving examples are found to be on eighteenth-century Scandinavian barns and were born from pure pragmatism. These systems featured an air chamber between an inner framed or masonry construction and an outer layer of lightweight siding, equalizing the air pressure across the building’s façade and preventing wind and pressure-driven moisture infiltration.1 Interestingly, early examples of rainscreens were only built on the wind-facing façade. At a time when few buildings had insulation, this additional layer also produced a buffer of air between inside and outside.

The introduction of the cavity wall in late nineteenth-century masonry construction, in England was another example of the introduction of an air cavity in the wall assemblage.2 The separation of the outer wythe by an airspace (now typically 1.5 to 2 inches wide) channeled the large amount of moisture that penetrated a brick or stone skin back to the exterior, usually through weep holes at the bottom of 1. John Straube, “Pressure Moderation and Rain Penetration Control,” pp. 1-9. See proceedings for the conference, Pressure Equalized Rainscreens: Design and Performance, Ontario Building Envelope Council, November 21, 2001, University of Waterloo, 2001, http://www.civil.uwaterloo.ca/

beg/downloads/pressure_moderation_seminar.pdf. (Accessed July 25, 2017) 2. Thomas Ritchie, “Notes on the History of Hollow Masonry Walls,” Bulletin of the Association for Preservation Technology 5, No. 4 (1973): pp. 40-49.

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Assemblages: The Speciation of the Envelope

Old dock buildings in Trondheim, Norway were systematically built with timber rainscreens to prevent water leakage due to wind-driven rain.

the wall assembly.3 So successful was this technique that building codes in England after World War II began mandating such an air space for masonry construction. The same idea is present in balloonframe construction in North America, though in the latter case, felts and corks were often added as waterproofing and insulating layers, a necessary addition to the lightweight walls.

Early instances of cavity wall construction can be seen in Victorian age (1837-1901) homes in the United Kingdom. In order to prevent dampness from penetrating masonry walls through capillary action, a double wythe wall with an air cavity between the wythes would occasionally be included in residential construction. Initially, the outer wythe was tied to the structure using bridging stones or bricks that connected the walls together.4 In the early twentieth century, the “row-lock” or “Rolok” brick assembly was used to generate the cavity.5 This method uses the length to width ratio of bricks to connect an inner and an outer brick wythe together around a void with a total width of around eight inches (the length of a brick). Variations on this form of construction included triple wythes of brick with a double-air cavity and alternating patterns of cladding and bridging bricks. However, problems with moisture penetration and degradation would occur through the bridging stones. This problem was later solved with the introduction of metal wall ties, serving to cut the capillary action of the masonry materials.6 But the wall ties were subject to thermal expansion and contraction as well as oxidation. Typically, metal ties could create an air gap of two inches, but they did not become the dominant form of cavity wall construction until the 1940s, after the introduction of the 1939 London Building Act model by-laws.7 3. See “Wall Cavities: Design vs. Construction” in The World of Masonry Construction (August 1, 1997) website: http:// www.masonryconstruction.com/how-to/construction/wall-cavities-design-vs-construction_o. (Accessed July 25, 2017)

5. Ibid.

4. “Why Cavities Cause Problems,” in How to Reduce Your Home Energy Bills (London, U.K., Centaur Media, 2014), p. 26.

7. Donald Friedman, “Curtain Wall Systems, 1890’s-1950’s” in Historical Building Construction Historical Building Construction: Design, Materials, and Technology. (New York: W.W. Norton & Company, 1995), p. 119.

6. Duncan Marshall and Nigel Dann, House Inspector (U.K., Taylor & Francis, 2005), p. 29.

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Screens: The Making of the Mask

The “rat-trap” bond is a primitive version of cavity walls, and the origin of the delamination of the wall to introduce an air layer to improve watertightness.

The benefits of constructing walls with an air cavity were clear to builders over a century before scientific investigations into building physics provided confirmation. After World War II, forms of cavity wall construction became standard in many types of envelopes.

While cavity walls are different from rainscreens because they are concerned with drainage more than airflow, the cavity wall nonetheless marks a crucial change in the conception of building envelopes: rather than blocking the flow of air and water through the building envelope, moisture and air are to be captured and adequately managed.

SCREENS AND ORNAMENTAL MODERNISM

Postwar architects declared, somewhat inaccurately, that prewar modernism had expelled ornament from buildings, an assertion that retroactively cast European modernism and the International Style as dogmatic trends with a rigid code of design conduct. The use of decorative elements in the 1950s and 60s, such as detached façade screens, found legitimacy as a rebellion against the perceived prohibitions of modernism. A precedent for today’s rainscreens, brise soleil and perforated ventilation walls became comprehensive envelope elements, producing idiosynchratic patterned effects.

One of the best-known examples of this is Paul Rudolph’s 1958 Jewett Arts Center in Wellesley, Massachusetts in which a surface of perforated metal panels, rendered with a tautly stretched, fabriclike quality, covers a partially glazed façade. Edward Durrell Stone also employed freestanding screen walls as one of his signature design gestures, as in the 1960 United States Embassy in New Delhi, with a screen wall composed of custom concrete masonry units. In his buildings, these assemblies ranged from custom-patterned, concrete masonry units (CMUs) to delicate wood and metal tracery. Deviating from the allegedly strict modernist dogma, these elements were conceived as and used for decorative rather than functional purposes. They identified a tendency toward ornamentation that would later prevail as an evolution of rainscreen technologies, eventually becoming one of the predominant façade assemblages.

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Assemblages: The Speciation of the Envelope

The Munich 1972 Olympic Stadium, designed by Frei Otto is one of the first large-scale use of PTFE in a building, and a huge experiment with tensile technologies, both on a geometrical and a material level.

— 380 —

Tensile Enclosures: From Comfort to Spectacle

4.6

TENSILE ENCLOSURES: FROM COMFORT TO SPECTACLE

The technologies that made the tensile façade possible were derived directly from military research, yet this assemblage has found its most frequent application in leisure buildings. This is perhaps due to its provisional nature as a light-weight and low-durability enclosure: the mostly synthetic materials that make this assemblage possible are equally well-suited for rapid deployment military shelters and airsupported pool enclosures. Once a symbol of a nomadic and extra-societal activity, the tensile façade has become increasingly engaged with temporary events and spectacles, facilitating multiple formal possibilities for building envelopes or economically cladding mega-structures for sporting events.

STABILIZED BY TENSION

Both pneumatic and tensile façades rely on the fact that, though flexible fabric or film sheets characteristically have no resistance to compression, if they are put under sufficient tensile force, they can become geometrically stable. There are two basic typologies of tensile structures: endotensile and exotensile. Endotensile structures are primarily stabilized by inflating fabric containers to produce tension in their surface. Exotensile structures are those where tension is applied to the fabric from the outside.1 Both of these typologies have been experimented with extensively, most successfully in large scale applications such as long-span roofs or cladding for large event spaces. Historically, tensile structures were used primarily for temporary applications such as coverings for protecting radar equipment or temporary exhibitions. However, tensile envelope technologies have become increasingly robust and climate effective in recent years, and materials such as ETFE are becoming the material of choice for large-scale, low-weight roof and wall applications.

The broad dissemination of these technologies has occurred at several points in the twentieth century. First, the discovery of synthetic materials led to a boom of tensile structures with military applications. Soon thereafter, as a culturally driven implementation of alternative cultures and new 1. Reyner Banham, “Monumental Windbags,” New Society 11, No. 287 (April, 1968): pp. 446-47.

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Detail of a NY Port Authority Bus Terminal media façade made os stailess steel fabric. LED diodes can be inserted in this lightweight mesh to turn cany façade into a media screen.

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Media Façades: From Information to Atmosphere

4.7

MEDIA FAÇADES: FROM INFORMATION TO ATMOSPHERE

In A Thousand Years of Nonlinear History, Manuel de Landa classifies material assemblages as Geological, Biological, or Linguistic depending on forms of entanglement between social orders, dynamical elements, living ecologies, and semiotic constructions.1 Architecture has traditionally been primarily mineral and only partially biological in its composition, although it has also had a significant investment in the linguistic, generally in the form of a language that is abstracted and embedded within material strata. While columns, beams, windows, and doors are the traditional signs in the language of architecture, media façades include those envelope assemblages that use literal materializations of codes or figures belonging to non-architectural forms of communication, such as written or pictorial media. Media façades have generally maintained two modes of performance: a linguistic mode, which uses the façade to convey information through verbal language; and a sensational mode, which uses the façade to communicate through atmosphere and affect—a performance that existed also in the traditional forms of architectural language. While façades that incorporate advertising have been common since the early twentieth century, media façades have increasingly turned toward the production of atmospheric effects.

MEDIA AND ARCHITECTURE

This is not a new alliance, as there are many examples of the incorporation of media to architectural envelopes. Media façades exist, for example, in the friezes of Greek temples or the façades and stainedglass windows of Gothic cathedrals. They are present wherever we can see the physical registration of linguistic and pictorial signs, where non-architectural narratives are collected in non-architectural codifications. Architecture has long been a medium onto which other forms of communication are applied. The images and inscriptions of both the stained-glass windows of Gothic cathedrals and friezes that have appeared in ancient architectural constructions across cultures have long lost their original meaning for us, becoming pure architectural sensations.

1. Manuel de Landa, A Thousand Years of Non-Linear History (Zone Books, 2000), pp. 19-22.

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Assemblages: The Speciation of the Envelope

The evolution from sign-based communication to sensation is one of the main trends in the evolution of media façades, both in the case of solid architectural elements and electronics technologies, but it is likely that even in their earliest manifestations their sensual performance would have played an important role in their design: stained-glass windows or bas-reliefs are not only about communicating a story, but also about inspiring a sense of awe. In the movie “The FoundThe Parthenon Frieze from the 5th century BC is the er” the character of Ray Croc (the founder of the paradigmatic example pictorial media being embedded in an McDonald’s chain) assigns the McDonald’s sign architectural substrate to tell a non-architectural narrative. on the buildings the same function that crosses or American flags have to represent churches or courts. The McDonald’s sign represents family, community, all-American values…2 Façades have long incorporated non-architectural signs as vehicles to communicate with diverse constituencies as a form of intertextuality in its broadest and most populist sense. However, it is the abstraction and reductivism of modern architecture that fostered the unprecedented and perhaps perverse need to use the sculpturally incorporated, the digitally infused, the written or pictorial media in order to convey non-architectural information.

MODERN SEMIOTICS: TEXT AND LIGHT

Gothic stained glass had already explored the effectiveness of light as an architectural device that could simultaneously communicate non-architectural messages and evoke powerful sensations. However, the mark of the evolution of media façades as a modern architectural assemblage arrived with the emergence of the incandescent light bulb. Slightly at odds with the purest forms of modern architecture and driven primarily by populist intentions, concerns for the commercial value or political spectacle, the introduction of electric lighting opened unprecedented possibilities to façade design.

The Electrical Building at the 1893 Chicago World’s Fair was perhaps the first time that large audiences were introduced to electric lighting and signage on a vast scale (particularly interior electric lighting).

After the success of the great World Fairs,3 facilitated by the movement from gas to electric lighting, information and architecture became inextricably linked through illumination—though not always harmoniously. Furthermore, the availability of electric lighting, which was finally safe enough to use reliably indoors, hailed an age of clean, sanitary modernism that no longer relied on the local burning of fuel for lighting (both a health hazard and a source of soot.) The history of the media façade can be understood as the history of both illuminated signage, as in displays “tacked on” to buildings, and buildings illuminated from within, whereby the volume of the building becomes a kind of urban lighting fixture.

2. This is allegedly the invention of Robert Siegel, the scriptwriter of John Lee Hancock’s The Founder (2016), not of Kroc himself. Or rather, an invention of Siegel’s wife. https://www.npr. org/2017/01/25/511655874/the-founder-follows-salesmans-genius-idea-to-franchise-mcdonalds. (Accessed June 24th 2019).

3. John E. Findling, Chicago’s Great World’s Fairs, Studies in Design and Material Culture (Manchester: Manchester University Press, 1995).

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Media Façades: From Information to Atmosphere

The 1930 Entry Pavilion for the Stockholm Expo by Gunnar Asplund is almost entirely composed of signage, a pre-postmodern decorated shed.

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Patrick Blanc’s Vertical Garden at the 2004 Quai Branly Museum in Paris by Jean Nouvel.

This was an early example of the lush green façades that became Patrick Blanc’s trademark.

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Vegetated Envelopes: Greenwashing

4.8

VEGETATED ENVELOPES: GREENWASHING

Is nature architecture’s nemesis? Not quite. The incorporation of vegetation into the façade has a long vernacular tradition—for example in the potted flowers seen in Andalusian, Swiss, and Flemish buildings. Furthermore, its linguistic incorporation into architecture dates back to long before the Corinthian order. In terms of theoretical engagement, this naturalistic lineage has developed from Vitruvius in the first century BC, to Abbé Marc-Antoine Laugier in the eighteenth century, to William Morris and Louis Sullivan in the nineteenth century. But it was not until the twentieth century that true living matter became part of the architectural expression of buildings, and only very recently that technologies have enabled planting to occur literally within the façades of buildings. With the rise of environmental consciousness in the 1970s, and the more recent environmental concerns collected in the Stern Report and the Kyoto Protocol, green envelopes have risen in popularity and become an almost generic assemblage. Drip-water systems and fertilizers are now able to ensure the growth of plants in almost any building surface. But not only that, green envelopes have now been loaded with symbolic value for an ecological strand of architecture. Whether there is a true net environmental benefit in implementing a green envelope remains under scrutiny, and the cost efficiency of large-scale green envelopes is utterly suspect.

THE HYBRID ORDER: BETWEEN THE GEOLOGICAL AND THE BIOLOGICAL

Over millennia, architecture has consistently maintained a modality that embodies vegetation symbolically, a sort of hybrid order between the geological and the biological. Many architects and theorists have addressed this issue on a material level, as buildings used to be built primarily with organic matter: wood. Vitruvius himself suggested that elements of the Greek orders, such as triglyphs, were a kind of petrified remnant of wooden construction techniques, and Laugier famously traced the Greek temple back to a primitive hut made with logs and branches.1 The interest in the vegetal in ancient architecture transcends the material into ornamental motifs.

1. Marc-Antoine Laugier, An Essay on Architecture, trans.

Wolfgang and Anni Herrmann (Los Angeles: Hennessey & Ingalls, 1977). First published 1753.

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Interior view of the US Expo Dome at the Montreal Expo in 1967 by Buckminster Fuller and Shoji Sadao. The original geodesic dome featured kinetic panels which could open and close to permit or block light from entering the space.

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Kinetic Assemblages: The Agency of Control

4.9

KINETIC ASSEMBLAGES: THE AGENCY OF CONTROL

Façades that incorporate moving parts have been present since the dawn of the machine age and have developed powerful cultural implications derived from their reactive nature. In its infancy, the dream of the fully automated envelope was always eclipsed by kinetic gadgets and components such as automatic windows, garage door openers, and mechanical heating and cooling. Recently, with increasingly sophisticated control technologies, entire façades with moving elements have become increasingly popular. With the rise of programmable micro-controllers, the future of the kinetic façade may be secure, yet its agency remains obscure in relation to shifting global environmental conditions and political processes. The kinetic assemblages appear to have a bright future through recent advances in maintenance and durability and effective performances on several environmental parameters (solar gains, air quality, energy consumption…), but more interesting, they seem to be also creating an increasing cultural fascination with mechanization. And to pose some complex questions about the agency of an automated architecture.

EPPUR SI MUOVE 1

Façades have always had moveable elements, even if these were never fully addressed in the classical disciplinar canons. Doors, windows, awnings, shutters, louvers, blinds, lifting bridges, and other kinetic elements have been necessary to modulate the otherwise static building envelope. Although many of these movable elements appeared naturally on the building envelope in order to allow the building to effectively regulate the conditions of daylight, access, and ventilation, they never developed into a disciplinary code such as the one that came to regulate the proportions of solids and voids and other compositional rules for building façades. Nevertheless, these elements accomplish critical performances on the envelope that we wish to address. Bruno Latour has famously stated that 1. This statement was allegedly made by Galileo in 1633 after he was forced by the Church to disavow his claims that the Earth orbits the Sun. “Eppur si muove” [“and yet it moves”] implies that it does not matter what the Church believes,

his observations and the conclusions he made from them still stand. The first record of this statement was made over a century later by Giuseppe Baretti in 1757. See: Giuseppe Baretti, The Italian Library (London: A. Millar, 1757), p. 52.

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THE ECOLOGIES OF THE BUILDING ENVELOPE A MATERIAL HISTORY AND THEORY OF ARCHITECTURAL SURFACES

Published by Actar Publishers, New York, Barcelona www.actar.com

Authors Alejandro Zaera-Polo, Jeffrey S. Anderson

Graphic Design Ramon Prat Homs Copy editing and proofreading Gavin Keeney, Walter Ancarrow

Image supervision Marta Bugés, Ricardo Devesa

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Printed in Europe Publication date: February 2021