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How to Clean an Asbestos Shingle Roof

  • Transcript

    LESLIE: Now we’re going to take a trusty cleaning question from Ken in Missouri.

    Ken, what are you looking to clean?

    KEN: An asbestos, slate-shingled roof.

    LESLIE: Wow.

    TOM: Now is it asbestos?

    KEN: Well, they look like slate but I’ve removed a couple of them and there’s a piece of paper on the back of one of them from 1952 and it says asbestos.

    TOM: OK. OK, they’re probably asbestos. They’re probably not slate. They’re probably asbestos. Because in the 50s, it was common to use a cement asbestos roof tile. Slate is going to look more like the slate that you might walk on and it exfoliates; it gets like delaminated. But the asbestos – here’s the good news about asbestos. It almost never wears out. So the roof, structurally, is probably fine.

    KEN: Very, very fine. Yeah.

    TOM: But the bad thing about it is it looks horrible. It grows – it attracts moss like you can’t believe it and it just really looks nasty. So you can clean it but I have to warn you that you’re going to have to (inaudible) it.

    LESLIE: (overlapping voices) Is this a do-it-yourself project or is this something you should hire a professional for safety issues?

    TOM: You know, it’s really – yeah, it’s really hard to clean because here’s why: it’s hard to walk on that stuff; it’s hard and it’s slippery. But what you can do …

    KEN: And it’s extremely steep.

    TOM: Yeah, it’s very steep. Here’s what you could do. If you want to try to clean it, you’re going to have to get a high pressure washer and you’re going to have to apply a cleaning solution to that first. It’s going to be one that is bleach-based or has a mildicide in it. You’re going to have to spray that down and let it soak and, after that, you can use the pressure washer to clean the roof and brighten it up. But the other thing is if you use too much pressure, you’re going to start to blast some holes in that asbestos. So this might be a situation where you’re just going to have to do a little bit of maintenance but you’re never going to get that asbestos shingle roof real bright, shiny white. You know what I mean, Ken?

    KEN: Yep. Yeah, I do.

    TOM: Yeah.

    KEN: Well, a contractor wanted $12,000 to replace it.

    TOM: Wow.

    KEN: Tear off the shingles, dispose of them, and put a new roof on.

    TOM: Well you know, interesting you talk about disposal. I hope he’s not running the cost up on disposal because in most parts of the country, disposal – removal of cement asbestos shingles is not regulated because that asbestos is held inside of a cement binder, so there’s low risk of any exposure to that. But disposal is regulated, so disposal is a little bit more tricky. But the removal is not that difficult. But if you ever do decide to reroof, make sure you take off the old ones because you don’t want to trap that under asphalt shingles. That would just make a big, stinking mess. OK, Ken?

    KEN: OK. I appreciate it.

    TOM: You’re very welcome. Thanks so much for calling us at 888-MONEY-PIT.

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