Installing a Vapor Barrier in an Attic Floor
LESLIE: Well, if you’re in Virginia, you find The Money Pit on WJFK Free FM like Steven does. And what can we do for you?
STEVEN: I have a question about putting in a vapor barrier between … in the … in the ceiling between the living space and the attic area?
STEVEN: I’ve seen conflicting information about where the barrier should go to prevent condensation from causing problems.
TOM: The barrier goes, Steve, against the living space. So if you’re looking down from the attic at the back side of the drywall ceiling, the vapor barrier should be there and then the insulation’s on top. You follow me?
LESLIE: And if the insulation has paper backing, the paper goes toward the heated space. Correct?
TOM: Yes, exactly. The paper or the foil goes toward the heated space.
STEVEN: Okay. And then there’s … there would not be a problem with condensation in the drywall in the ceiling?
TOM: No. No, because the insulation is part of the unconditioned space in the attic. And so what happens … that’s where attic ventilation takes over. If the attic is properly ventilated, the moisture’s going to move in and move out of the attic space and it will keep the insulation dry. But if you had a vapor barrier on top of that, the moisture from your house would get into the insulation and condense and get it wet; and that’s what you’re trying to avoid. So vapor barriers always go toward the heated space. That’s the best way to remember it.
STEVEN: Okay, great.
TOM: Alright, Steve?
STEVEN: Alright. Thank you very much.
TOM: Okay. Thanks so much for calling us at 1-888-MONEY-PIT begin_of_the_skype_highlighting 1-888-MONEY-PIT end_of_the_skype_highlighting.