STRUCTURAL GLASS FACADES - USC School of Architecture

equalization and air and water barriers. Great complexity has evolved in these designs in an
effort to control water and air penetration. These systems typically use pressure gaskets to
seal aluminum to aluminum and aluminum to glass. The problem is that when these
systems leak, the leaks often propagate along the extrusions and may penetrate the building
interior a great distance from the actual source of the leak.
An alternative technique used in specialized circumstances is a weather seal comprised of
field applied wet silicone, most often in the form of a butt joint (see Figure 2.40) between
adjacent panels of glass. The advantage to this technique is that, if properly applied, the
seals have a track record of being leak free indefinitely. Leaks in the system are easily
identified and repaired. The downside is the requirement for field application of the silicone,
requiring site labor which is both expensive and prone to quality problems; the application of
a silicone seal is more easily accomplished in the factory than in the field. The silicone seal
is typically applied from the exterior. It may be possible to develop a hybrid system that
includes a pressure gasket seal in the floor slab area with butt-glazed silicone elsewhere. If
the cables were exterior to the glass plane, the silicone could be installed from the inside.
Site labor in the US construction market is extremely expensive, resulting in an effort to
design building systems in a manner to minimize the site labor requirements. For the cable
supported curtain wall system to be viable, two problems must be solved; 1. getting
individual glass panels into place quickly and easily, and 2. facilitating the application of the
silicone weather seal. The potential exists for the development of an automated material
delivery system for the glass panels, and the development of a robotic tool to apply of the
weather seal. Both systems could be designed to work off the parallel tracks of vertical
cables. The entire integrated cladding system could represent a patentable new cladding
technology.
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