LESLIE: Randall in Texas is on the line and has a question for us about trying to extend his bathroom exhaust vent to the roof. How can we help you today?
RANDALL: Yes, I had a question about a bathroom vent that’s on a second floor.
RANDALL: And the duct to it is vented up into the attic but it’s not going out through the roof. It’s just kind of up there in the attic. And of course, the roof has ridge vents and everything. And one of the questions that I had – would that pass an inspection if I’m going to sell the house?
TOM: Right. So, basically, your bathroom vent – your plumbing vent – is terminating in the attic. It does not go through the roof to the exterior. Is that correct?
RANDALL: Not the plumbing vent. The exhaust vent.
TOM: Oh, the bathroom exhaust vent. OK. Alright.
TOM: So, the answer to your question is no. The bathroom exhaust vent is not done correctly. And the reason for that is because when you take all that warm, moist air that accumulates in the bathroom from bathing and you vent it up into the attic, the first thing it’s going to do is condense on the underside of the coldest part, which is the roof sheathing.
Now, a couple of things can happen when that occurs. In the wintertime, that condensation will be drippy and it will get down in the insulation. And when the insulation gets damp, it doesn’t insulate nearly as well. Secondly, most of the year, it’ll keep that lumber and that sheathing wet and damp. And if that wood stays over about 25-percent wet, it starts to delaminate and very often, you’ll see mold and plywood deterioration because a bath was not properly ventilated.
The solution is pretty easy, though. You’re going to want to add a duct from that vent fan to the exterior in the shortest way possible. But I would definitely do that to avoid dumping all that moist air into the attic. That’s the right way to fix the bathroom exhaust vent, OK?
RANDALL: OK. So I need a roofer so he can cut the roof and …
TOM: You know, you don’t necessarily need a roofer. A carpenter could do this. Go to HomeAdvisor.com and look for a carpenter or a handyman or a roofer. And read the reviews, because they’re – all of the guys on that site are thoroughly reviewed. And this is exactly what I would do if I was going to find – need to find somebody in my area. In fact, I have done it this way. And you’ll find a roofer or a carpenter or a handyman that can do this job.
It’s a very small project. It’s very easy, very straightforward. And that would be the best way to get it accomplished, OK?