Why Is My Commercial Storefront Glass Leaking? Diagnosis Guide

Commercial storefront glass leaks have six common causes: sealant joint failure, gasket compression failure, weep system blockage, frame movement past design tolerance, anchor failure, and original installation defect. Diagnosing which one requires a field inspection. Here is the framework, in order of how often we find each.

Cause 1: Sealant joint failure (most common, years 3-15)

Weatherseal sealants typically fail at year 5-7 if installed poorly, year 10-15 if installed correctly. Visual signs: cracking, separation from substrate, mold growth in joint. Fix: full sealant joint cut-out and re-seal with compatible structural-grade sealant (Dow Corning 795 or 791, Sika SikaFlex). Cost: $8-15 per linear foot of joint.

Cause 2: Gasket compression failure

EPDM or silicone gaskets compress over time and lose seal. Common at year 10-15. Visual sign: visible gap between gasket and glass or frame, or daylight visible through joint. Fix: gasket replacement on affected openings. Glass must be removed (or re-glazed) to swap gasket. Cost: $35-65 per linear foot.

Cause 3: Weep system blockage

Aluminum storefront systems have weep holes at the sill to drain water that gets into the frame. If blocked by debris, paint, or sealant, water backs up and leaks inward. Fix: clear weep holes (low cost), drill new weeps if originals were blocked at fabrication. Cost: $200-500 per opening.

Cause 4: Frame movement past design tolerance

Building settlement, thermal expansion-contraction, or storm-induced flex can move the frame past the assembly's design tolerance. Result: cracked sealant joints, gasket displacement, hardware misalignment. Fix: assess structural movement, address the root cause if possible, then re-seal and re-align the storefront.

Cause 5: Anchor failure

Rare but serious. Anchor pullout from substrate corrosion, undersized anchor design, or substrate failure. Fix: complete anchor replacement after structural assessment. Cost: high. Insurance coverage often required.

Cause 6: Original installation defect

Improper anchor density, missing sealant on first install, gasket misalignment, or wrong sealant chemistry. Discovery typically inside 2-year installer warranty. Warranty work — contact the original installer for repair.

Frequently asked questions

How fast can ACG diagnose a commercial storefront leak?

Field inspection within 1-3 business days of call. Diagnosis report within 5 business days. Remediation scope and bid within 10 business days of inspection.

What's the typical commercial storefront leak repair cost?

Sealant re-do on a typical storefront opening: $400-1,200. Gasket replacement: $1,500-4,000 per opening. Weep clearance: $200-500. Full anchor remediation: high cost — typically tied to structural assessment.

Can ACG repair leaks on storefronts ACG didn't install?

Yes. ACG repairs commercial storefronts installed by others. We diagnose, scope, and remediate. Original installer warranty (if any) is a separate issue — we can document the defect for warranty claim purposes.