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  1. #1
    Join Date
    Jun 2004
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    Portland, ME
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    Default Removing stain/growth from asphalt shingles

    I have a client who wants to put her house on the market, thinks she needs to remove this staining - it's a shaded north side. I told her I was worried anything we used would just discolor it in the opposite direction and that the risk wasn't worth the slight reward, but she's determined. Anyone have any ideas?
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  2. #2
    Join Date
    Jul 2007
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    Northern Jersey
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    Default Re: Removing stain/growth from asphalt shingles

    Having trouble seeing the problem, is it one siding or the shingles?

    They make zince strips that go under the ridge caps. A narrow reveal is left exposed and allows minerals in the strip to wash down over the roof. Kinda like seeing clean sections of a white roof under a dormer or vent that has aluminum or copper flashing.
    Tom

  3. #3
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    Northern Jersey
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    Default Re: Removing stain/growth from asphalt shingles

    We actually have a local guy advertising roof cleaning without power washing. Claims to completely brighten dark stained roofs from lichen and extractive bleeding. I am hoing to find out more about what kind of solution they are using.
    Tom

  4. #4
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    Default Re: Removing stain/growth from asphalt shingles

    It's the roof, and we're going to put some zinc or copper under the tabs, but I don't think that will get rid of the staining, just kill the growth. And I agree it's hard to see.

  5. #5
    Join Date
    Sep 2009
    Location
    Portland, Maine
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    1,375

    Default Re: Removing stain/growth from asphalt shingles

    What's it from? Did you pee out the window or something?

    Edit: no window, you peed off the roof then?
    Portland Renovations, Inc.
    www.portlandrenovations.com

  6. #6
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    Northern Jersey
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    Default Re: Removing stain/growth from asphalt shingles

    Could be.....bee/hornet spray will stain roofs.
    Dont know what can be done about that.
    Tom

  7. #7
    Join Date
    Jun 2004
    Location
    Georgia
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    Default Re: Removing stain/growth from asphalt shingles

    I can see it perfectly well, and it would bother me too if the rest of my house looked that good. I'm guessing it's just mildew that has grown in the shady area, as it does on north-facing siding. Should be real easy to take care of with a pressure washer with plain water, or maybe a long-handled brush. No risk.
    Last edited by charles; 04-26-2012 at 08:18 PM.

  8. #8
    Join Date
    Jul 2006
    Location
    Portland, OR
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    2,460

    Default Re: Removing stain/growth from asphalt shingles

    Moss and mildew killer (for surfaces - not the kind for lawns) from the nearest big box store. Spray with hose end sprayer, let it work. Hose off.

  9. #9
    Join Date
    Sep 2004
    Location
    down the shore
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    2,244

    Default Re: Removing stain/growth from asphalt shingles

    I don't know that you are going to get it much better, Dan.

    If it was the whole roof that was affected and needed cleaning, maybe. But in my experience, just doing one spot can often make it look worse, esp since you have a dark colored roof.
    Last edited by S.Joisey; 04-29-2012 at 04:43 PM.

  10. #10
    Join Date
    Jun 2004
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    Portland, ME
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    Default Re: Removing stain/growth from asphalt shingles

    That's my concern. We'll try a hose and stiff brush to start.

  11. #11
    Join Date
    Aug 2009
    Location
    St. Paul, MN & Northern WI
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    275

    Default Re: Removing stain/growth from asphalt shingles

    Dan:
    Hell..., that’s a shadow, just move the sun a few degrees in the sky or rotate the house 90° and it should go away. :-) The stain almost looks like the footprint of a long lasting snow drift.

    Otherwise, won’t a stiff brush or pressure washer remove half the granules too. Can you try any solution you use on a small area first, and in longer and longer times btwn. application and wash off (retention times) to assess the results. Then, maybe wash that whole plane of the roof surface to blend things out. But, a whole different roof plane, and any slight color change, won’t be very noticeable. All of the standard suggestions for these situations, and a real PITA, nonetheless.

    The copper strips prevent (inhibit) algae, and the like, from forming and growing. I think that produces a very dilute copper sulfate solution when it rains, thus preventer. You could try a more concentrated solution of copper sulfate, but you must catch this because it will kill any vegetation it contacts. A fairly concentrated solution of water and household bleach sprayed on, and left to dry will many times kill this kinda stuff. The bleach is what I use in a couple places where tree sap seems to be food for moss on our cabin roof.
    Dick Hackbarth, PE
    RWH&AI, Consulting Engineers

  12. #12
    Join Date
    Jun 2004
    Location
    Portland, ME
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    6,302

    Default Re: Removing stain/growth from asphalt shingles

    Thanks, all - we'll try some things next week. Was thinking about diluted bleach too.

  13. #13
    Join Date
    Sep 2004
    Location
    Mid Hudson Valley
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    314

    Default Re: Removing stain/growth from asphalt shingles

    Our painter had literature on a product called Wet and Forget, www.wetandforget.com Though we did not try it yet, the idea seams appealing for gently cleaning surfaces. Supposed to be ecologically responsible. For what its worth

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