Buddy from Fort McMurray told me to use spray foam in my rim joist

He swore by that Great Stuff stuff for sealing up the basement rim joists. Did the whole job last fall and now I'm worried I trapped moisture in there. Anyone else deal with mold after using spray foam down there?

2 comments

2 Comments

emery_lopez25d agoTop Commenter

I mean, "caught it early" is the key there, but maybe it's not just about mold. Idk if anyone's thought about this, but spray foam can actually make your rim joist rot from the outside in if there's any gaps in your siding or brick above it. Water gets behind the foam and can't dry out, so it just sits there against the wood all winter. I'd poke a couple small holes in the foam down low and check with a screwdriver to see if it's damp back there before it gets worse.

umathompson25d ago

Oh man that's a tough spot to be in. I hope it's not too bad down there and you caught it early.