How to Reduce Attic Moisture
LESLIE: Alright. Now we’re going to head on up to the attic with Eric in Alaska. What’s going on at your money pit?
ERIC: Oh, well, we bought a home this last year and unfortunately, the home inspector we’d hired neglected to find a lot of problems and one of them was they didn’t put a vapor barrier up in the attic. And so we’re in the midst of doing all the court issues with that and I’m trying to find something I can do to mitigate the migration of the moisture up into the attic or move it out of the attic until we can do permanent repairs.
TOM: Alright. Well, first of all, when you say there’s no vapor barrier in the attic – so you’re referring to vapor barrier between the ceiling and the insulation?
ERIC: Correct. Yeah, they didn’t do anything. They just – we have knotty, hardwood pine interior and they …
TOM: OK. Just laid the fiberglass on top of it? Is that what happened?
ERIC: Well, they had blown insulation – blown-in insulation.
TOM: Oh, blown-in insulation. OK.
Well, you’ve got to manage your moisture, as you’re well aware, and the best way to do that in an attic is with a combination of roof vents. You want to use a ridge vent that goes down the peak of the roof. Do you have a ridge vent right now?
ERIC: Right now, we just have eave vents and gable vents.
TOM: Alright. So what – I think you ought to think about installing a good-quality ridge vent right down the peak of the roof. That really opens up the attic and lets it breathe. I would get one that’s made by the AirVent Corporation. It’s a CertainTeed company. The reason I say that is because the metal vent that AirVent makes, it has sort of a baffle on the side of it, if you look at the profile, that really speeds up the depressurization. So as wind is blowing over your roof, it depressurizes that ridge and really draws air out of that.
But that’s only half of the ventilation system. The other half is soffit vents at the overhang of the roof. So if you add soffit vents and a ridge vent, then what happens is air presses into the soffit, it rides up under the roof sheathing and exits at the ridge. And that’s a cycle that runs 24-7, 365, so you’re always sort of washing drier ambient air through that attic and pulling moisture out at the same time. That’s a very effective way to go.
ERIC: Yeah. No, we have a metal roof here. So, do they have an application for a metal roof?
TOM: Yeah. I don’t see why you couldn’t use a ridge vent on a metal roof. The specific type of ridge vent may be a little bit different and of course, the installation’s a little bit different but we see metal – we see ridge vents and other types of vents on metal roofs all the time. The roof still has to breathe, metal or wood.
ERIC: OK. Yeah.
ERIC: Yep, yep. Alright. Thank you much.
TOM: You’re welcome. Thanks so much for calling us at 888-MONEY-PIT.