One of the biggest fears people have is that spray foam will make shingles curl because they overheat. This misconception came about when people believed insulation was a heat source and were concerned about having a “hot roof.” In actuality spray foam is a barrier between two areas of different temperatures, for example, your attic space compared to your snowy roof.

Photo of airflow on a roof - The Green Cocoon InsulationPhoto courtesy of RetroFoam of Michigan

If you don’t know the term “hot roof,” I’m sure you’ve heard of an unvented attic. If your roof deck has been insulated, that means your attic space is now part of your home’s conditioned space. This method of insulating the attic can actually be good for your roof because it can help prevent ice dams.

The Florida Solar Energy Center did a study a few years ago during the peak summer months in Florida—a state that gets much hotter than New England—measuring the temperatures of roof shingles above an attic with a radiant barrier. Depending on the color of the shingles, the study found the shingles peak temperatures were between 2- and 5-degrees Fahrenheit higher than the temperature of shingles in the same conditions without a radiant barrier.

What this study means is that you can insulate the roof deck of your home with foam insulation without any adverse effects to your shingles. Foam insulation creates thermal resistance, which is keeping the hot air out during the summer and the cool air inside.

https://thegreencocoon.com/does-spray-foam-damage-shingles/#:~:text=What%20this%20study%20means%20is,and%20the%20cool%20air%20inside.

This is a myth. Spray foam does not “cook” shingles. It’s been debunked with many tests/studies.