Another Install Fail: Structural Mullions

Written By Kenneth Sandlin

In hurricane zones, structural mullions aren’t optional—they’re critical.

Steel or aluminum structural mullions must be installed before the windows and doors, and they must be engineered to resist the calculated wind loads for both the system and the opening.

Aluminum tube mullions have their own product approvals and must be installed exactly per testing to comply with Florida Product Approval (FPA) or Miami-Dade NOA standards.

Skipping this step? That might be fine in 20–30 mph winds. But in storm-force conditions, your opening will likely blow out.

I help architects, builders, and owners avoid these failures by ensuring every component—from structure to glazing—is planned and detailed for real-world performance.

Another Install Fail: Structural Mullions

Kenneth Sandlin
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