Aesthetics in Glass Structures, 2004

Visual Aesthetic

Glass in architecture is appreciated more for its aesthetic value, particularly its transparency, than as a dielectric material or an information highway, although environmental concerns are shifting the visual aesthetic to energy issues. Only in recent decades have we seen this demand, and consequently, industry has responded by producing new glass types which can be exploited in architecture as truly dielectric materials.

The most important glass types for construction are oxide glass types based on silica and prepared by cooling. Silica forms the network and metal oxides modify it. It is the viscous properties of glass which permit such a wide range of compositions and different properties.

Glass construction is dependent upon other structures – either foundations or a superstructure. Therefore, we must understand these structures’ short and long term dynamic behaviour. Once the scale is understood, it is possible to design the interface between glass and structure, and to resolve other issues, such as material compatibility, within a desired aesthetic objective. Most architects, though, are not interested in the fundamental process by which this can be achieved. Architects seem concerned primarily with the products available on the market, how much they cost, and how best they can serve aesthetic and environmental standards for their designs. Apart from art applied to or etched onto the surface of glass, the history of architecture reveals that architects have not fully exploited glass, yet the aesthetic possibilities of glass are virtually limitless.

Before the sixteenth century, glass was mostly used in ecclesiastical buildings and considered to be a luxury. As economic flat glass was developed it was used in secular buildings, but early on it was not of sufficient quality to ensure undistorted views. During the mid-late nineteenth and early twentieth century, glass manufacture allowed architects to dream of the transparent envelope. It was the development of float glass in the mid-twentieth century which brought this dream to reality.

In the past thirty years toughening of this float glass and more recently the introduction of quality controls and heat soaking has permitted architects to realise this dream fully. However, examples of glass constructions that pose a danger to the public still occur far too frequently. Currently, the structural uses of glass and aesthetics are intimately related.

Twenty five years ago, architects began dreaming of the dynamic glass wall – a wall which could respond at the flick of a switch to become opaque, polychromatic, transparent; a wall which could change its thermal performance, capture energy and transfer this energy to other parts of the building, and carry information. Ten years ago architects, influenced by the media age, began dreaming of information walls.

Decoration has for much of the twentieth century been discarded in a purge of architectural selfcleansing. Light symbolised goodness, illumination, rationality, order, and hygiene. Early in this century, glass became an aesthetic in its own right; its crystal transparency symbolised rational and economic thought. Throughout the twentieth century architectural aesthetes abjured decoration on the grounds of virtue.

This ubiquitous material’s uniqueness lies in its ability to refract and reflect light. Glass is phenomenal. Its smooth and durable surface can take a multitude of textured surface treatments which no other material can approach – yet continue to refract light. It can be graduated from transparency through degrees of translucency to opacity; pattern and profile rolled; macro and micro etched by machine; sand and acid etched; drilled and micro-perforated by acids; bodycoloured and stained; enameled and painted; fired, and printed.

Today, some people think of the stained glass window as an anachronism, the product of basic glass technology when only small pieces, uneven and of irregular thickness, could be manufactured. However, the essential perceived qualities of the stained glass window are the same as those of today – luminosity, translucidity and composition. The fact that we have so many more techniques does not camouflage these qualities. Now, we can compose with the new composite techniques to achieve higher levels of environmental performance: coloured and interference laminates, processed holographic film sandwiched between glass, pixellated electroluminescence, photochromism, holograms, dichroism and switchable crystals, photovoltaics, information technology, metal deposits coatings, and in the not too distant future, biogenetic coatings and perhaps embedded miniaturised generators and lasers as nanotechnological products become available. The application of these techniques should seek to create responsive thermal and more intelligent glass enclosures for buildings. But, at the same time, these applications can also go beyond the technical and harmonious integration of glass in buildings to seek to inspire, excite and be as didactic as stained glass windows were so long ago.

© Ian Ritchie – May 2004