Fact or fiction – spray foam will damage your roof shingles and void your warranty.
This is fiction and comes from the early days of insulating attics. People used to believe insulation was a heat source, which is where this myth comes from. Unfortunately, there are still contractors who believe this is the gospel and say that spraying the roof deck could void any warranty on the shingles.
RetroFoam of Michigan has more than 15 years of experience insulating attics, so we’ve heard from homeowners their concerns about their shingles. We’ve also helped to alleviate those fears once those homeowners start feeling and seeing the benefits.
I have more than 33 years of experience in the construction industry, so I can tell you from my experience that spray foam insulation isn’t going to hurt your shingles. You don’t have to take my word for it, but I have found research to back this up to put your mind at ease.
Is Spray Foam Bad for Shingles?
The first time I encountered this was when I was talking to a homeowner who had done a ton of research before requesting an estimate.
Unfortunately, during her research process her roofer told her the spray foam would make her shingles curl because they would overheat. I explained to her where this misconception comes from, when people believed insulation was a heat source and were concerned about having a “hot roof.”
Hot roof is a term that comes from the earliest days of insulating attics.
Spray foam insulation is actually a barrier between two areas of different temperatures, so your attic would be the same temperature as the rest of your house even though it is cold outside.
If you’ve never heard the phrase “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 unvented system could make the temperature of your roof go up a little, but I found research that states that slight temperature change won’t hurt your shingles.
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 Michigan – 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 that hot air out during the summer and your cool air inside.
Insulating Your Attic with Spray Foam
Now that we’ve shown you the research and you see for yourself that your shingles won’t curl or get ruined, you might be curious about the benefits of foam insulation in your attic.
You can find all of the answers to your questions, as well as some you might not have even thought of at the Learning Center on our website.
About Garry Barlow
Garry's experience helps him understand the building of new homes and the layout of existing homes. He has also taken building science classes at the Building College of Manchester. Meeting new people and having a different experience everyday are just some of Garry’s favorite things about his job. When Garry isn’t working, he’s watching soccer, eating pizza, and spending time with his family.