Preventing Concrete Slab Sweat

Get tips on preventing concrete slab sweat. Slabs sweat when there is too much moisture, so make sure your home has good drainage and a good gutter system to prevent water damage later on.

LESLIE: Rosetta in Illinois needs some help with a cabin. What’s going on at your money pit?

ROSETTA: Well, we are building this cabin and we had a contractor come in and pour the concrete slab. And we didn’t realize that he did not put plastic underneath it. So now the floor is sweating. We’ve already got the frame on it and how – is there anything we can do to prevent this from getting worse?

TOM: Yeah, a couple of things. First of all, since the home is still under construction, once it’s done you want to be very, very careful to have good outside drainage because that’s going to reduce the amount of water that sort of hangs out at the edge of the concrete slab. So we’re talking about making sure you have a good gutter system and good grading that slopes away from the walls. And then the other thing to do is after it gets sort of as dry as you think it’s going to get, I would add a couple of coats of masonry sealer. That will stop some of the water from evaporating into the home and raising the humidity, which I think is what you’re experiencing right now.

ROSETTA: It’s called a masonry sealer?

TOM: Yeah, a masonry sealer. Yes, a concrete sealer.

ROSETTA: And I can pick that up at any home improvement …

TOM: Any home center, yeah. You know, do it before – you know certainly before you get any floor coverings down. Maybe when the frame is done you could start putting a couple of coats of that down right at that point.

ROSETTA: OK. Great. Thank you very much.

TOM: You’re welcome, Rosetta. Thanks so much for calling us at 888-MONEY-PIT.