Crawlspace: Insulate and Install Moisture Barrier
LESLIE: Baird in North Carolina, you’ve got The Money Pit. What can we do for you today?
BAIRD: I’ve got a pest control service that comes out on a regular basis for termites and bugs.
BAIRD: And the last three times they’ve been out, they’ve been trying to sell me a vapor barrier to go down on the ground under the house. They said my moisture content is too high. The last trip they came out, they wanted to do the moisture barrier and insulate my floor.
BAIRD: My question is the house is 100 years old, it’s on a sandy soil, and I’ve never had anybody, over the years – and I’ve been in the house for 50 years – never had anybody tell me this before. I don’t know if they’re just trying to make a sale or if there is a problem. What moisture percentage should I be worried about?
TOM: Baird, I would say yes and yes; they’re probably trying to make a sale. That said, installing a moisture barrier – which is nothing more than some plastic across the sandy floor of your crawlspace – is a pretty good idea because you do get a fair amount of evaporation of moisture from the soil up into the crawlspace area. That can condense, get into the house, it can cause a mold problem. But it’s pretty simple to do; I mean if you can get down in that crawlspace and unroll some heavy visqueen plastic. You want to use as big of a piece as possible with as few seams as possible and simply lay it edge to edge all along the foundation wall. That will trap a lot of moisture underneath it and make that area dryer.
In terms of the insulation, also a good idea if you’d like the floor to be a bit warmer. Again, not a difficult project. You use unfaced fiberglass batts. They’re held in place with wire springs. They’re sort of pieces of wire – looks like hanger wire – that’s cut to be just a little bit longer than the width between the floor joists and that’s what supports the batts up into the floor and, again, it’ll keep it a bit warmer.
So these are good improvements. Whether or not you hire the pest control company to do them or not is totally up to you, but I’ll tell you they’re pretty simple and you certainly could do them yourself.
LESLIE: Mm-hmm. And they’re worthwhile to do.
BAIRD: That sounds great. I think it’s something that I’m going to do myself.
TOM: You go for it, Baird.
BAIRD: Thank you much. Listen to your program and really enjoy it.
TOM: Thanks so much for calling us at 1-888-MONEY-PIT.