Should I Put Rocks on Top of the Plastic Sheeting in My Crawlspace?

LESLIE: Bela in North Carolina is calling in; needs some help with a project. What can we do for you?

BELA: We have a crawlspace.

LESLIE: OK.

BELA: And then we put heavy-duty plastic on the ground, you know, to keep the moisture in the ground.

TOM: (overlapping voices) OK. So far so good.

BELA: And then one of my neighbors is a contractor. He says you need to put crushed stone over it so it is flat. And then there is another contractor. He said, “No, don’t do it because the moisture going to condense on the rocks and then you’re going to have water on top of the plastic.” So which way should I go?

TOM: Well, I don’t think there’s any reason to put the rocks on top of the plastic. There’s no reason whatsoever to do that. You just want to put heavy-duty plastic down and what that does is that stops the soil moisture from evaporating up into the crawlspace and it keeps the humidity down. So there’s no reason to put anything above that. You’re not …

LESLIE: No, the only concern is that if you’ve had to use more than one piece of your plastic sheeting to sort of cover that ground area, you need to make sure that you’ve got a really large overlap so that you’re not allowing moisture to escape.

TOM: Right.

BELA: So you don’t think that’s a good idea?

TOM: (overlapping voices) I don’t think it’s necessary.

BELA: (overlapping voices) I already shoveled two cubic feet or two cubic yards of crushed stone under the crawlspace.

TOM: No, not necessary. Put the plastic right on top of the soil and be done with it.

BELA: Ah, that’s very – thank you very much. I wish I contacted you two weeks ago. (chuckles)

TOM: (chuckling) OK. Bela, thanks so much for calling us at 888-MONEY-PIT.