You want spray foam insulation in your attic, but you’ve heard through the grapevine that it will void the warranty on your shingles.

This honestly depends on the company that you purchased your shingles from. Some people think that spray foam in your attic will damage the shingles, but that’s not the case. It is this way of thinking that leads some manufacturers to add this clause in their shingles warranties.

RetroFoam of Michigan has been insulating attics across the lower peninsula since 2002. With this experience, we know the spray foam we use isn’t going to damage your roof or shingles. We also know that in many applications, insulating the roof deck is the best way to seal the envelope of the home.

In our continued effort to educate homeowners, we have gathered some information that will answer your questions about warranties.

Roof Shingle Warranty

Most companies that produce shingles have different policies regarding their warranty and spray foam insulation.

There are some companies that will flat out void your warranty if you apply spray foam to your roof deck, others that will only approve the use of their spray foam product, and some that will not void your warranty with the use of spray foam.

In most cases, companies recommend spraying the attic flat instead of the roof deck.

It all comes down to the company you decide to go with. Here are a few examples.

Atlas Roofing has a technical bulletin discussing its policy on roof deck spray foam insulation. Because spray foam creates an air barrier, it would void Atlas’ shingles warranty. They do however offer an alternative.

“Spray-In-Place Foam Insulation that is installed in a manner that provides continuous adequate airflow directly below the shingle nailing surface and is permanently installed,” the document states. “The provided air flow must be continuous from the eaves unimpeded through to the highest point of the roof area (ridge), available directly below the decking to which the underlayment and shingles are attached.”

CertainTeed lists spray foam insulation applied to the roof deck as one of the acceptable forms of insulation in its warranty. The company further warns of insulation materials that can lead to air leaks and condensation problems, as the growth of mold and mildew is not covered under the warranty.

When it comes down to it, if you want spray foam in your home and you need new shingles it will be important to work with a roofing contractor who also understands the benefits of foam insulation not only for your home but for your roof as well.

Will Spray Foam Damage Roof Shingles?

While doing your research did you come across blogs claiming spray foam would make your shingles curl because they would overheat?

This is a common misconception about spray foam insulation that comes from the early days of insulation. People first believed insulation was a heat source and thought they would end up with a “hot roof.”

Spray foam actually creates a barrier between two areas of different temperatures. This means your attic would be the same temperature as the rest of your home if you insulate the roof deck, even if it’s cold outside.

You may not have heard about a hot roof, but in your research, you probably did read about the unvented attic system.  

If you’re considering insulating your roof deck, this makes your attic part of your home’s conditioned space. This is actually good for your roof because it helps prevent ice dams.

While this unvented attic system could make the temperature of your roof go up slightly, it’s not enough to hurt your shingles.

Insulating Your Roof Deck with Spray Foam

The best thing you can do is look over your shingles warranty to see if spray foam could void it.

While we know that our product will not harm your shingles, it really comes down to each manufacturer's policy. If you know spray foam is the best fit for your attic but it could void your warranty, opt to spray the attic floor instead of the roof deck.

While this process completely cuts your attic off from the rest of the house, it will keep you from losing air through the attic and roof.

If you’d like to learn more about foam insulation and its benefits, check out the Learning Center on our website.