LESLIE: Kent in Kansas has an issue with bathroom ceiling stains. What is going on at your house?
KENT: I have a vent that seems to maybe be – have some condensation or whatever. But I’ve got some stains that I’m – bathroom ceiling. And I have tried to spray the, you know, the ceiling stain to fix it but it continues to be a problem. And I wonder, how do I – what do I have to do up in the attic to take care of that?
Now, I do have a furnace up in the attic area, so I don’t know if that has anything to do with it. But I think it’s associated with a bathroom vent.
TOM: Well, typically, when you get a ceiling leak causing bathroom ceiling stains, it’s caused by the plumbing vent where it exits the roof. Because all bathrooms are going to have a vent pipe that goes up. It’s about 3 inches wide and it goes up from the bathroom, through the roof. And there’s a rubber boot around the pipe that seals the water out.
But the problem is that the rubber boot isn’t nearly as durable as the shingles around it. And the sun beats on it and the UV rays start to break it down. And then you’ll get a gap around the pipe and then the water, when it rains, kind of hugs the pipe, works its way down the pipe. It will drip off or find another route and end up somewhere in the vicinity of the bathroom ceiling. So that would be the most common type of bathroom leak; it wouldn’t be the vent – the bathroom fan, although it’s possible. But it’s probably not it. It’s more likely the plumbing-vent flashing causing bathroom ceiling stains.
So I would take a look at the outside, from the roof. Identify where that pipe is coming through the roof and see if the plumbing-vent flashing is deteriorated. If it is, easy fix. You take a couple of shingles off, put a new piece of flashing on, retack it back in place and you’re good to go.
Once you’ve eliminated the leak, then what you can do is spray that stain with a little bit of a bleach-and-water solution, let it – rinse it off, wipe it dry. And then I want you to prime the entire ceiling with a solvent-based primer. So, oil-based or alkyd-based primer because that’s the only thing that will seal that black in. And then you could put whatever top color you want on top of that and that could be latex, OK?
KENT: Is something like a KILZ product – is that what you’re talking about?
TOM: Yep. That’s exactly right. Yep, KILZ would be fine.
KENT: Alright. That’s what I’ve been using to take care of the stain. But it continues and so I (inaudible).
TOM: Alright. Well, if it’s – listen, if it’s continuing – the KILZ product you’re using, is it the water-based or is it oil-based?
KENT: I believe it’s oil-based and …
TOM: How are you cleaning your brushes? Are you cleaning the brushes with water or are you cleaning them with mineral spirits or turpentine?
KENT: I am using the spray can.
TOM: Oh, it’s in a spray can?
TOM: It’s probably the alkyd. I would get a little quart or a pint can of the oil-based KILZ. You could put it on heavier that way.
TOM: And just enough to get rid of bathroom ceiling stains, alright? And that’ll make a difference.
KENT: It actually looks like it’s cracking. Is that – is it to the point where I’m going to have to repair the drywall?
TOM: Well, what’s cracking? Is there a seam that’s cracking?
KENT: Yeah, in the ceiling, right in the very center of where the stain is is a small crack.
TOM: Uh-huh. Right.
KENT: And I’m almost afraid to touch it for fear that I’m going to put my finger all the way through it.
TOM: Well, if that’s the case, you’d better find out now and not later. So, yeah, I would poke around a little bit. But a little bit – a small crack in drywall is not a big deal. Just Google “plumbing-vent flashing.”
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