My buddy Craig swore by spray foam for soundproofing and now I'm fixing mold 8 months later

So last spring I was building out my backyard studio and my friend Craig who does HVAC work kept insisting I use closed cell spray foam for insulation and soundproofing. He said it was the only way to get a tight seal and keep noise from leaking. I went with it, spent about $1,200 on the spray foam, and sealed up the walls real good. Fast forward to last week and I pulled off a panel to run a new cable and found black mold growing behind the foam where moisture got trapped. Turns out spray foam in a shed that doesn't have perfect ventilation is a disaster waiting to happen. I had to rip out three panels and now I'm looking at tearing down half the wall to treat the mold. Craig still says I just didn't seal it right, but a buddy of mine who builds studios for a living told me rigid mineral wool panels are the way to go for backyard sheds because they breathe. Has anyone else run into moisture problems with spray foam in a small space like this?

2 comments

2 Comments

the_shane2d ago

Yeah, shortcuts usually just cost you double in the end.

wendysmith1d ago

Oh man, learned that one the hard way with my last car. Thought I could save a few bucks skipping a proper mechanic, ended up paying triple to fix what I broke trying to be clever. Always seems to work out that way lol.