Finding the Source of a Roof Leak

LESLIE: James in California listens to The Money Pit on Discovery Radio. How can we help you?

JAMES: Well, OK, I do have a problem with my roof. The add-on part is a two-story and the – somewhere, when it rains, the water is coming down the wall on the inside. It isn’t coming down on the outside. The shingling looks really well. I mean it is fairly old but … I’d say, probably, oh, 20 years old maybe is the shingling on it right now. It’s composition shingles. And somehow, the water is getting in and running down the inside wall.

TOM: OK. Well, let’s talk about the areas of the roof that are typically most vulnerable. That would be, first of all, where anything comes through the roof. So, if you have a plumbing vent pipe, if you have a chimney, if you have the vent for your furnace or for your dryer. Whatever is going through the roof, areas around there are really the first thing to check.

The second thing is you mentioned that your composition shingles are 20 years old. Well, that’s about as old as those shingles are going to last. And the way they deteriorate these days may not be that easy to see. It used to be, in the old days, you would look at the shingle and it would sort of curl up and get very, very brittle. But shingles today don’t curl up anymore. What they do is they fissure and they crack but sometimes you can’t see it until you’re right on top of it. And as they do crack, they will let water get in.

And thirdly, what you want to do is look for any areas where there are roof intersections; where two sections of the roof come together, such as a valley or a place where a low roof and upper roof come together. Those are the areas that generally leak.

Now, the next thing that you could do to try to limit this and identify where it is, is simply do a hose test. See if you can get some water running down the roof in the area of the leak and see if you can actually make it leak without having water go, you know, through all sides of the house. Once you identify where that leak is coming in, you’ll have a better idea of what it’s going to take to fix it.

JAMES: Oh, that’s a good idea. I didn’t think about doing that. Yeah, it’s an open beam ceiling and it just seems to be strictly coming down the inside wall. I just cannot figure out how to … but I’ll give that a try.