Many an apartment-dweller dreams of waking up, pulling back the drapes or raising the blinds, and gazing out their floor-to-ceiling windows toward the horizon, sunlight flooding the space around them. For the lucky few that’s not a fantasy – and those lucky few owe the experience to the development of the glass-and-steel curtain wall.
A Little History
Prior to the development of the curtain wall, the frame, floors, and walls of a building rested on the building’s foundation. The taller the building, the thicker the foundation, and the thicker the exterior walls, generally both built from stone or masonry. The strength of the foundation and the walls supported the interior structure loads.
The introduction of the curtain wall changed everything. It enabled architects and engineers to design and build taller buildings, and permitted more light into the interior of those buildings. The first curtain wall buildings were constructed in the United Kingdom in the mid-19th century.
Curtain wall construction is a hallmark of the Chicago School of architecture and the development of skyscrapers. The first ‘skyscraper’ in Chicago to feature curtain wall construction with a predominantly glass façade was the 10-story Home Insurance building built in 1885 at the corner of LaSalle and Adams Streets. The building came down in 1931, but the use of curtain wall façades continued to develop, primarily with steel frames. By the 1950s the glass front became a symbol of post-war architecture and continues to be so today.
How It Works
The overall concept behind this type of construction is fairly straightforward. The structure of the building is a steel frame built on a concrete foundation. Individual floors are also poured concrete. The curtain wall, usually an aluminum frame which holds the glass, literally ‘hangs’ on the steel frame, secured to it with a system of silicon sealants and gaskets.