Why does nobody talk about moisture barrier failure in old garages

My uncle Joe told me his 67 Mustang had been sitting in his detached garage for 15 years with zero issues, but when I helped him move it last month we found the floor was damp and the carpets were soaked. Turns out the vapor barrier under his concrete slab had degraded and all that moisture was wicking up through the floor and into the car's interior. Anyone dealt with this kind of hidden moisture problem in their storage space?

3 comments

3 Comments

the_lee1mo ago

diana512, fifteen years with no issues and then it just soaked through - that was pretty much my exact reaction when I saw my own garage floor situation. I had a leaky roof that I thought was just the shingles getting old, but when I pulled up the old linoleum, the concrete underneath was wet as a sponge. Turns out my vapor barrier had failed too, and I'd been parking my daily driver right on top of a moist slab for months. I guess that's what I get for ignoring the musty smell that I figured was just old oil and gas smells. Problem is, once that moisture gets up, it finds its way into anything porous, and your uncle's Mustang carpets are proof of that. I ended up having to rip out the whole floor and put down a new vapor barrier, which was about as fun as it sounds.

diana5121mo ago

Fifteen years with no issues and then it just soaked through? That's insane.

betty_wells1mo ago

Fifteen years means that roof has been through thousands of rainstorms and temperature swings. Most materials start breaking down around the 12 year mark, so you actually got lucky. Check your attic insulation and ventilation too, sometimes the problem is trapped heat and moisture building up from inside, not the roof failing.