My neighbor's shed floor taught me a $200 lesson about vapor barriers

I was helping my neighbor, Frank, move an old workbench out of his shed last spring. The floor was just a concrete slab he poured himself about 5 years ago. When we lifted the bench, the wood legs were totally rotten and soft, and you could see a dark, damp patch on the concrete underneath. He just shook his head and said, 'I skipped the plastic sheet under the slab to save eighty bucks.' That dampness had been wicking up for years, ruining anything that sat directly on it. It wasn't even a wet area, just normal ground moisture. Now he's looking at having to rip everything out and seal the top, or worse, re-pour a section. It really stuck with me because my own shed slab was going in the next month. I spent the extra on a proper 6 mil barrier without a second thought. Has anyone else had something simple like that come back to bite them years later?

3 comments

3 Comments

john_fisher24d ago

That part about it not even being a wet area, just normal ground moisture, is what got me. I used to think vapor barriers were overkill for small slabs like a shed floor. Figured it was just for basements or wet ground. Then I saw a garage floor where they stored cardboard boxes directly on the concrete. The bottom of every box was a soggy, moldy mess, and the concrete was always dark. The owner said the same thing, just saved a few bucks skipping the plastic. Changed my whole view. Now I see it as cheap insurance.

roberts.leo24d agoMost Upvoted

Guess that plastic sheet is the real hero in the fight against soggy cardboard!

hayden_ramirez24d ago

My old apartment's concrete floor ruined a perfectly good guitar case, same deal.