Off-Ratio Foam: Why Standard GL Won't Cover Bad Batches

Off-ratio foam is the nightmare scenario of every spray foam contractor. A proportioner problem, a temperature issue, or a chemical supply irregularity produces foam that doesn't cure right — and by the time you find out, it may be installed in an entire building.

The damage is real: failed insulation, corrosive off-gases, structural concerns, and a remediation bill that can easily hit six figures. The bigger problem is that your standard general liability policy almost certainly won't pay for it.

The Exclusion That Catches Contractors Off-Guard

Standard commercial general liability contains a products-completed operations exclusion for faulty workmanship — the policy doesn't cover the cost of redoing or removing your own work. On top of that, many GL forms add explicit exclusions for chemical products liability or professional application errors.

When off-ratio foam causes damage, the carrier's position is often:

• The foam failing to cure is a workmanship defect — not covered under GL
• The chemical reaction going wrong is a products liability issue — excluded or sublimited
• The removal and reinstallation is your work — not third-party property damage

Without coverage specifically designed for spray foam, you're looking at paying remediation out of pocket.

What Off-Ratio Coverage Actually Covers

Purpose-built spray foam insurance includes off-ratio coverage that addresses the real exposure:

• Product failure claims — when foam doesn't perform as specified
• Third-party property damage from off-gassing or failed foam
• Removal and reinstallation costs when bad foam must come out
• Chemical sensitivity and exposure claims from building occupants
• Consequential damages — contents, finishes, and structure affected by failed foam

This coverage sits on top of your GL and fills the gaps the standard form leaves open.

The Proportioner Problem

Most off-ratio incidents trace back to the proportioner — a flow imbalance between the A-side and B-side chemicals. Even a small percentage drift in ratio can produce foam that appears normal during application but fails as it cures.

The job looks done. The contractor leaves. Weeks later, the client notices soft spots, shrinkage, or an off smell. By then, the foam is inside walls, under roofing membranes, or in a crawl space — and remediation is labor-intensive and expensive.

A good spray foam insurance program anticipates this claim pattern because it's the most common large loss in the industry.

What to Check on Your Current Policy

Pull your GL policy and look for three things:

1. Products-completed operations coverage — is it included, and at what limit?
2. Chemical or pollution exclusions — does your policy treat foam off-gassing as a pollution event?
3. Faulty workmanship carve-outs — does your policy explicitly address application defects?

If your current GL was written by a general contractor carrier without spray foam expertise, it almost certainly has all three problems. A policy built for spray foam addresses them directly.

If you're not sure where your coverage stands, a 15-minute conversation can tell you. The time to find out is before the claim, not after.