A Chicago landmark still sealed strong - 50 years after one of the world’s first 4-sided SSG applications.
In the heart of downtown Chicago stands a little-known pioneer in building envelope design - a structure that quietly helped prove the durability of structural silicone glazing (SSG). The School of the Art Institute of Chicago’s building at 280 South Columbus Drive, completed in 1974, was one of the world’s first major 4-sided SSG applications.
Nearly 50 years later, much of that original sealant is still performing.
At the time, structural silicone glazing was still in its infancy. Fewer than ten projects globally had used SSG, and most required mechanical clips for safety. But the team behind this project - architects Skidmore, Owings & Merrill and fabricator Flour City - partnered with GE Silicones (now Momentive Performance Materials) to do something different. They trusted a relatively new, SilPruf sealant, for this bold glass façade.
The building’s mirrored glass panels were field-glazed with 1-part alkoxy cure silicone sealant - creating a structural joint between the laminated glass and anodized aluminum frame. It was among the first to fully commit to structural glazing without added mechanical supports. A full-scale mockup was tested to glass failure in the lab.
The result? The silicone held firm.
By the mid-1990s, 20 years after installation, samples of the original sealant were lab-tested. Despite two decades of exposure to Chicago’s harsh winters and wind, the material showed no change in elasticity, tensile strength, or Shore A hardness.
Fast forward to 2013: during a retrofit of the clear vision glass to improve energy efficiency, more sealant samples were tested. Again, no measurable degradation.
Now, in 2025, the building’s iconic mirrored glass façade remains untouched. The original silicone sealant continues to perform - making this project a powerful, real-world case study in the long-term performance of structural silicone glazing.
This SAIC building wasn’t just ahead of its time in appearance - it set the tone for what was possible in curtain wall construction. The grey silicone used (a departure from the dominant black of the era) even anticipated a future trend in architectural aesthetics.
Half a century on, this project reminds us that with proper design, materials, and installation, structural silicone glazing can endure for decades.
Architect / Designer: Walter Netsch of Skidmore, Owings & Merrill (SOM)
Performance results are those of reported accounts, and are not to be relied upon as typical or expected under any other circumstances. Performance results will vary depending upon a number of factors. Prospective customers should rely solely upon their own evaluative techniques to determine what results are attainable and optimal to their specific needs. Further note that MPM is not endorsed by or affiliated with the owner(s) of SAIC.
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