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Clean Moss and Mildew From a Roof

  • Transcript

    LESLIE: Now we have a call from Wendell in Tennessee who wants to clean his roof shingles.

    Wendell, tell us where on the roof is this dirt.

    WENDELL: It’s under some oak trees. Shingles are a light-gray color. I just wondered if it’d be worthwhile to try to clean them. It may just be time for a new roof.

    LESLIE: So you’re seeing this mildew build up primarily under the trees.

    WENDELL: Probably mildew, yes.

    TOM: Well the good news is that it’s probably moss; or mildew but probably moss. And it doesn’t really damage the shingles. In actual fact, it actually puts another layer on that the sun can’t get through because the sun is the enemy of the roof shingles. But it is ugly and we can understand that and the way to get rid of that, Wendell, is to put a mildicide on top of it first. Now you could use something like a Clorox bleach solution where you’d mix bleach and water. You put it on there and you’ve got to let it sit and then you can follow that up with a pressure washer set on very light pressure and kind of wash that away and that will brighten those shingles up.

    WENDELL: OK, I wondered about the pressure washer.

    TOM: Yeah. Just not with too much pressure. That’s the key. Because the more pressure, the more abrasion you put on those shingles, the shorter life they’re going to have.

    WENDELL: Understand. Take them right off there.

    TOM: Exactly.

    WENDELL: OK, thanks for taking my call.

    TOM: You’re welcome, Wendell. Thanks so much for calling us at 1-888-MONEY-PIT.

    You know, it’s also worth mentioning that the new roofing shingles today actually have mildicide built into them that makes this a lot less likely to occur.

    LESLIE: But it still has the possibility of occurring.

    TOM: It could. And another thing that Wendell could try – or anyone else that has this situation – is you could try replacing the vent on your roof. If you have a ridge vent and you have a roof that gets very, very dirty, you can try replacing it with either a copper vent or a nickel vent. Because as the rain water washes over those vents, some of that metal actually gets released into the water and it acts as a mildicide and keeps the roof scrubbed clean.

    LESLIE: Oh, wow.

    TOM: So even putting a piece of copper on top of the ridge kind of acts as a sacrificial metal and it converts it to a mildicide. That rain water will actually wash your roof. So if you have a very dirty roof, that’s one thing you can try.

    OK, Wendell? Thanks so much for calling us at 1-888-MONEY-PIT.

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