Find the Source of a Roof Leak
LESLIE: Gary in Connecticut, what’s happening at your house?
GARY: Well basically the situation is that I’ve got a – it seems like a small leak. I notice a brown spot. I have a gabled roof. And I’m just curious as to is there any way you can determine where the water’s coming from?
LESLIE: Where are you seeing the brown spot?
GARY: It’s at the very bottom where the slanted ceiling actually meets the top of the wall.
TOM: So, you’re seeing this inside your house?
GARY: Yes, I am.
TOM: Are there any bathrooms or any other type of an obstruction that goes through the wall in this area? A chimney, a plumbing vent pipe or something of that nature?
GARY: Nothing like that but it is an extension on the house. The rest of the house is higher. This comes out as an extension and the roof is lower than the rest of the house.
TOM: Because generally, roofs are going to leak at intersection points or where things come through the roof.
Now, a good way to test this – are you sure this is an active – this is active right now?
GARY: Oh no, no. It’s occurred and then it’s gone away. It only happened once or twice.
TOM: Alright well, here’s what I think you should do. Take that spot and paint it with a primer. I want you to use a KILZ oil-based primer because that’s going to seal in that – there’s a chemical reaction that occurs sometimes with ceiling paint or regular latex paint and the stain that’s left behind by a leak. And what it’ll look like is you’re painting it over and then it’ll seem like it comes through. So I want you to paint that spot over with primer first. And then, you know, repaint it with your topcoat and keep an eye on it.
If you’re convinced there’s still an active leak and we’re in the leak diagnosis stage of this, then what you should do is you should get a garden hose and you should start low on the roof and flood that roof with water and then work your way up to see if you can figure out where it’s leaking. I can suggest to you that it’s probably most likely at an intersection point like where the roof cuts into the old part of the house.
LESLIE: I mean it could be as simple as just needing to revamp your flashing over there.