Warning: Don't buy those spray foam insulation kits from the hardware store

I spent $180 on a DIY spray foam kit to seal my attic in Calgary last spring and it ended up costing me $600 to have a pro rip it all out because the foam expanded way more than I expected and warped my roof trusses, has anyone else had a DIY insulation job backfire this bad?

3 comments

3 Comments

logan5611mo ago

Had a buddy try this same thing in Edmonton and his garage door stopped opening after the foam pushed the frame out of square.

xena_bailey181mo ago

Seems a bit dramatic to me. I've used those kits in my basement rim joists with no issues, just gotta follow the temperature guidelines and not go overboard. Sure it can get messy but warping trusses sounds like a specific product or application problem.

the_brian1mo ago

Wait, you said "basement rim joists"? That's a completely different world from what we're talking about. I'm sitting here trying to picture someone spraying foam up into a truss setup on a second story or something (yikes). You might be getting solid results in a basement because the conditions are more controlled and the foam has less room to expand wrong in that enclosed space. Man, I'm kinda shocked nobody mentioned that before now. It changes the whole conversation. Basement rim joists are basically the foam's best friend, but up in the attic or around engineered trusses? That stuff can get wild if the temp's off or the can's a little too hot. I've heard stories of it basically turning into a monster expanding blob that pushes things around. For real though, I'm glad it's working for you in that spot. Just don't try it on anything load-bearing without checking the foam's expansion rate first. That's where people get into trouble, you know?