Glass is one of the modern marvels of architecture today, and it has a long and rich history. Zahner has played a role in the use of glass in architecture since its founding in 1897 when the firm manufactured glass skylights for modern buildings. Today, Zahner continues to work with modern and ancient glass systems, including cast and sheet glass, blown glass, fused glass, and a number of stained glass projects for art and architecture.
HISTORY OF GLASS IN ARCHITECTURE
Some of the earliest uses of architectural glass appeared in the cities of Rome, Herculaneum, and Pompeii. The first windows were made during Rome's early Imperial Period (1 century BC to 3rd century AD). However, the glass was nearly opaque in this day, and served more for security and insulation. It was most often seen used in the public baths to prevent drafts and provide security.
The glass used architecturally at the time had very little illumination due to the thickness and roughness in which it was cast. This window glass was typically cast, but in some cases also blown. In casting, the panes were poured and rolled over flat wooden molds lined in a layer of sand. Blown glass was crafted through cutting and flattening a long cylinder of blown glass.
It would be another Millenia before glass was first used to provide a clear view in an architectural context. First as stained glass, in which metals were added to glass in order to create different colors. The first research towards this end was happening in 8th century Persia, Mirrors were first invented as a result of these experiments in Arab Islamic Spain. In 12th century A.D. Germany, the first churches and important secular buildings began to use these techniques. Combined with recent discovery of soda glass, this marked the beginning of widespread usage of stained glass windows, a tradition which continues to this day.
MODERN GLASS IN ARCHITECTURE
In the 19th and 20th centuries, modern architectural glass went through a renaissance. A number of techniques emerged which provided different strengths and weaknesses, from crown glass, to cylinder glass and drawn sheet glass. In the 1950s the invention of float glass created a real industry — today most of the glass we see is made using this process. It is made by floating a layer of molten glass on top of a molten bath of tin, a soft pliable metal. In this process, both faces of the glass are given a smooth appearance. The finished product has near-perfect parallel surfaces.
As a manufacturer of the total building envelope, Zahner has developed a number of works with architectural glass working in tandem with a metal facade systems. Examples of this include the de Young Museum in San Francisco, in which Zahner was responsible for the entire facade system, which included a number of custom curving glass forms. Zahner worked with the manufacturer of the glass to supply a complete system for Herzog & de Meuron-designed building with Fong and Chan Architects.