Materials and architecture

The relationship between architecture and materials had been fairly straightforward until the Industrial Revolution. Materials were chosen either pragmatically – for their utility and availability – or they were chosen formally – for their appearance and ornamental qualities.
Locally available stone formed foundations and walls, and high-quality marbles often appeared as thin veneers covering the rough construction. Decisions about building and architecture determined the material choice, and as such, we can consider the pre-19th century use of materials in design to have been subordinate to issues in function and form. Furthermore, materials were not standardized, so builders and architects were forced to rely on an extrinsic understanding of their properties and performance.

In essence, knowledge of materials was gained through experience and observation. Master builders were those who had acquired that knowledge and the skills necessary for working with available materials, often through disastrous trial and error.
The role of materials changed dramatically with the advent of the Industrial Revolution. Rather than depending on an intuitive and empirical understanding of material properties and performance, architects began to be confronted with engineered materials. Indeed, the history of modern architecture can almost be viewed through the lens of the history of architectural materials.

Beginning in the 19th century with the widespread introduction of steel, leading to the emergence
of long-span and high-rise building forms, materials transitioned from their pre-modern role of being subordinate to architectural needs into a means to expand functional performance and open up new formal responses. The industrialization of glass-making coupled with developments in environmental systems enabled the ‘international style’ in which a transparent architecture could be sited in any climate and in any context. The broad proliferation of curtain wall systems allowed the disconnection of the fac¸ade material from
the building’s structure and infrastructure, freeing the material choice from utilitarian functions so that the  facade could become a purely formal element. Through advancements in CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) technologies, engineering materials such as aluminum and titanium can now be efficiently and easily employed as building skins, allowing an unprecedented range of building fac¸ades and forms. Materials have progressively emerged as providing the most immediately visible and thus
most appropriable manifestation of a building’s representation, both interior and exterior. As a result, today’s architects often think of materials as part of a design palette from which materials can be chosen and applied as compositional and visual surfaces.

It is in this spirit that many have approached the use of smart materials. Smart materials are often considered to be a logical extension of the trajectory in materials development toward more selective and specialized performance. For many centuries one had to accept and work with the properties of a standard material such as wood or stone, designing to accommodate the material’s limitations, whereas during the 20th century one could begin to select or engineer the properties of a high performance material to meet a specifically defined need. Smart materials allow even a further specificity – their properties are changeable and thus responsive
to transient needs. For example, photochromic materials change their color (the property of spectral  transmissivity) when exposed to light: the more intense the incident light, the darker the surface. This ability to respond to multiple states rather than being optimized for a single state has rendered smart materials a seductive addition to the design palette since buildings are always confronted with changing conditions. As a result, we are beginning to see many proposals speculating on how smart materials could begin
to replace more conventional building materials.

Cost and availability have, on the whole, restricted widespread replacement of conventional building materials with smart materials, but the stages of implementation are tending to follow the model by which ‘new’ materials have traditionally been introduced into architecture: initially through highly visible showpieces (such as thermochromic chair backs and electrochromic toilet stall doors) and later through high profile ‘demonstration’ projects such as Diller and Scofidio’s Brasserie Restaurant on the ground floor of Mies van der Rohe’s seminal Seagram’s Building. Many architects further imagine building surfaces, walls and fac¸ades composed entirely of smart materials, perhaps automatically enhancing their design from a pedestrian box to an interactive arcade.
Indeed, terms like interactivity and transform ability have already become standard parts of the architect’s vocabulary even insofar as the necessary materials and technologies are far beyond the economic and practical reality of most building projects.

Rather than waiting for the cost to come down and for the material production to shift from lots weighing pounds to those weighing tons, we should step back and ask if we are ignoring some of the most important characteristics of these materials. Architects have conceptually been trying to fit smart materials into their normative practice alongside conventional building materials. Smart materials, however, represent a radical departure from the more normative building materials. Whereas standard building materials are
static in that they are intended to withstand building forces,smart materials are dynamic in that they behave in response to energy fields. This is an important distinction as our normal means of representation in architectural design privileges the static material: the plan, section and elevation drawings of orthographic projection fix in location and in view the physical components of a building. One often designs with
the intention of establishing an image or multiple sequential images. With a smart material, however, we should be focusing on what we want it do, not on how we want it to look.

The understanding of smart materials must then reach back further than simply the understanding of material properties; one must also be cognizant of the fundamental physics and chemistry of the material’s interactions with its surrounding environment. The purpose of this book is thus two-fold: the development of a basic familiarity with the characteristics that distinguish smart materials from the more commonly used architectural materials, and speculation into
the potential of these characteristics when deployed in architectural design.