How to Find and Fix Roof Leaks

  • roof leaks
  • Transcript

    LESLIE: Well, water stains on your ceiling can signal a leaky roof. But pinpointing the exact source of that leak can be harder than it seems.

    TOM: True. But with a few simple tips, you can find roof leaks and get them fixed before the roof leaks get worse and worse and cause yourself a major roof leak and all the damage that could ensue. For that, we turn now to general contractor Tom Silva from TV’s This Old House.

    Thanks, Tommy, for stopping by The Money Pit.

    TOM SILVA: It’s my pleasure. It’s nice to be here.

    TOM: Now, when you spot a roof leak, it would seem that the source should be right on top. But that’s just way too easy, isn’t it?

    TOM SILVA: Yeah. Way too – don’t I wish that? No, it’s never right above. Well, I shouldn’t say never but 99 percent of the time, it’s somewhere else.

    TOM: Rarely.
    TOM SILVA: You can have a roof leak on the opposite side of the roof and it works its way down around the shingles and leaks right over your head in your bedroom.

    TOM: So if you’ve got one of those tricky roof leaks and you really need to figure out where it’s coming in so you know what to do to fix it, where do you begin?

    TOM SILVA: Well, I begin if you can get in the attic, first of all, and look up there, see if you can see the water stains.

    TOM: OK.

    TOM SILVA: The other way is then you have to climb up on the roof and see if you can see any shingles missing or anything like that. It’s good if you have a good pair of binoculars. You can really inspect the roof from the ground. You don’t even have to get up there. So you can look at the roof, you can look at the shingles, you can look at the flashing around the chimney, any penetrations, like the vents.

    TOM: Now, that’s a good point because roofs seldom start leaking right in the middle of a perfectly flat, good shingle. I mean it’s almost always where something comes through the roof, like a pipe or an intersection between sections of a roof.

    TOM SILVA: Exactly. Yep, yep. So you’ve got to get up there and find out. And believe it or not, you’d be amazed what you can see from the ground, like I say, with a good pair of binoculars. You can see a crack in that gasket that goes around that vent pipe.

    LESLIE: So if all else fails and I really just cannot find where this leak is coming from, is it smart to sort of get up there with a friend and spray some water out of a hose to try to recreate a rainy condition and see where it’s happening?

    TOM SILVA: Not that smart. I would say stand on the ladder, on the edge of the roof, and then spray it with a hose.


    TOM SILVA: Don’t get up on the roof. It can become slippery.

    TOM: Now, let’s say that we’ve actually found the leak and we know what’s going on. I think folks are almost always looking for the easy solution here. And by the way, sometimes roofers look for the easy solution, too, because it’s a guarantee of repeat business. And they want to put some sort of a roof sealant or a tar-like substance on the roof but that never seems to last very long.

    TOM SILVA: No, the tar will break down, crack over time. Your leak is going to get right back again.

    TOM: So what’s the best approach?

    TOM SILVA: You can basically remove the shingles in the area or the roofing that’s in the area around the chimney and you may have to reflash. Usually, that’s the best way around a chimney.

    TOM: So, essentially, don’t look for the shortcut. Take the roof apart in that particular area and then rebuild it the way it was always supposed to be done.

    TOM SILVA: Exactly. Around a vent, there are actually repair kits that you can place right over the pipe and set it right down on top of that vent flashing. You seal around it and push the vent seal right over it and that problem will be solved right there.

    LESLIE: Is it like a rubberized gasket that has a flange?

    TOM SILVA: Yeah. It’s a rubberized gasket. So if you have the rubberized gasket, you have the metal ones and the plastic ones, there’s actually a gasket at the top. You can actually take that gasket out of a new one and slide that gasket right on top of the existing gasket. But I like to seal underneath that with a tripolymer caulking, push it right in there and it’ll seal it right up. But don’t use silicone and don’t use tar.

    TOM: Now, why not use silicone? That, I think, would surprise a lot of people because they think that that’s one of the most durable sealants out there.

    TOM SILVA: No, silicone is a fantastic sealer for anything that is non-porous. Anything that is porous, the silicone will break away from it over time. And once it starts to break away, you can’t recaulk it without removing all of the silicone. So you want a type of material that’s flexible, pliable and will stick to different types of material and can be resealed if needed.

    TOM: And that’s why he’s the expert general contractor on TV’s This Old House.

    Tom Silva, great advice as always. Thanks so much for stopping by The Money Pit.

    TOM SILVA: My pleasure. Great to be here.

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