STRUCTURAL GLASS FACADES - USC School of Architecture

Design Considerations
Aesthetics: Often similar to stick systems, but there is more flexibility with unitized systems
because of the factory assembly. Units can be structurally glazed, meaning the glass is
glued to the exterior of the frame with structural silicone, and no cover plate is required on
the exterior of the glass. This serves to mitigate the strong framing grid, providing an
uninterrupted glass surface. Custom curtain wall designs can become quite elaborate.
Transparency: Typically somewhat less than with stick systems, as the splitting of the
mullions around the perimeter of the units results in a wider combined mullion band.
Geometric flexibility: Unitized systems are more complex than stick systems, and are even
more impacted by added complexity to the building form.
Design issues: Like stick systems, unitized systems must be carefully designed to
accommodate building movements and to provide pressure equalization to the system to
prevent water and air infiltration. The necessary requirement to evolve unitized systems from
their stick-built predecessors into a modular system was to split the mullion at the
intersection of the units. This complicated the unit design while at the same time providing
new opportunities for accommodating building movements.
Glass System Interface: The glass is continuously supported on the frame.
Glass type: There are no limitations to the glass type used except those imposed by code
requirements.
Resources and Technology
Materials and Processes: The primary difference here is where the work is performed;
unitized systems are shop assembled facilitating the processes. There is general parity
between framed systems with respect to glass and panel materials.
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