Why I stopped using expansion foam on every rough opening

Tbh I used to foam every window and door frame like it was the gospel, but after a job on a commercial build in Spokane last March the GC made us rip it all out because it was trapping moisture against the WRB. Has anyone else run into this issue on tighter buildings?

2 comments

2 Comments

milestaylor24d ago

Wait, were they using closed cell or open cell foam? I had a buddy who did insulation work up in Montana and he said the same thing happened on a passive house project, the builder was using the wrong type of foam and it basically turned the whole wall into a sponge. I switched to using a vapor permeable gasket tape on my own house after that, and honestly I feel way better about it. The foam just seems too unpredictable once you get into high performance buildings with weird climate zones. I’m not saying foam is always bad, but I think people treat it like a magic fix and then wonder why their walls rot out five years later.

pat_schmidt6024d ago

I actually read a study from Building Science Corp a while back that showed closed cell foam can trap moisture if it's installed over damp sheathing, especially in colder climates like the PNW or Montana. The foam acts like a vapor barrier on both sides, so if any water gets in it's stuck there forever. Seems like your buddy saw the same thing happen firsthand.