Understanding Hurricane Product Approvals – Why Sealants Are a CRITICAL FAILURE POINT

Yesterday I learned something new from an engineer colleague—and it’s a big deal.

In hurricane glazing, sealants are often the weak link. Especially when using unsupported storefront jambs (the default install method), tall frames will deflect under wind load and pull sealants beyond their tested limits.

For example:

• A 10'–12' tall jamb will flex under pressure.

• The product approval likely assumes DOWSIL 790, rated for +100% / -50% joint movement.

• But most subcontractors aren’t using that—they’re using cheaper sealants with lower stretch ratings.

Here’s the problem:
The approval requires a 3/8" gap at 9' or taller so the sealant can stretch.
If you only have 1/4" of space or are using the wrong product?
👉 That sealant will FAIL and LEAK.

Are they using proper backer rod? Anchored or unanchored jambs? Following the shop drawings exactly?

Don’t rely on the inspector. Most are only checking anchors—not verifying sealant compliance.

I help teams review shop drawings, vet product selections, and make sure the sealant spec actually matches the tested assembly—because no one wants to find out the hard way.

Why Sealants Are a CRITICAL FAILURE POINT