How to Install a Plastic Vapor Barrier
LESLIE: Al in Nebraska finds The Money Pit on KFOR. And how can we help you and your money pit today?
AL: Yes, I have a question here about putting like a one-room addition on a house and some people put a plastic vapor barrier over the insulation and before the sheetrock or the drywall. And I was wondering why they do that and is that needed. I mean should a person do that or not?
TOM: That’s a good way to make a very tight house. It’s another way to seal those walls. And a vapor barrier is fine. It always goes against the living space so it’s in the right spot on top of the existing insulation, on top of studs before the drywall. So that’s the way it’s – that’s the reason it’s put up there. You know, keeping the vapor pressure from getting into the insulation and vice versa and keeping the draft from getting in is all helped by that. Because you have to remember, when we build a house we frame the wall. It’s kind of like we’re starting with Swiss cheese and everything else we put in there is designed to fill a hole one way or the other; whether it’s insulation, siding, a window or a door. So adding a continuous, solid vapor barrier to inside before drywall is a good idea. You know, you can only do it in new construction and that’s why you should take advantage of it when you can.
AL: OK, I thank you very much.