what gets black off the roof

Discussion in 'Power Washing' started by jeremy067390, Apr 26, 2007.

  1. jeremy067390

    jeremy067390 LawnSite Member
    Messages: 49

    i dont know what to use foor that black bleeding on the roof. i tried stuff from xterior that was for the houses said it didnt that too. nope. pored the chlorine right on there nope. ive been able to thin it out with pressure but thats about it. ive got two jobs in limbo some1 help me out

    FCPWLLC LawnSite Senior Member
    Messages: 352

  3. Duekster

    Duekster LawnSite Fanatic
    from DFW, TX
    Messages: 7,961

    Yep, chlorine is a good killer but does not have any surfactants and will not clean. The TSP will do that.
  4. GreenN'Clean

    GreenN'Clean LawnSite Bronze Member
    Messages: 1,512

    I've noticed the Black Bleeding only happens on cheap shingles I had a customer want me to power wash his roof last year but I turned it down because the shingles was cheap and I didn't want to damage the shingles and then have to put on a new roof...

    FCPWLLC LawnSite Senior Member
    Messages: 352

    More often than not, what you describe as bleeding, is just Algae stains.

    Simple application of sodium Hypochlorite and TSP followed by a rinse with Garden Hose is all that is needed. No Pressure washer involved.
  6. squirtgun

    squirtgun LawnSite Member
    Messages: 88

    The black bleeding is not from the shingles.It's a form of algae that feeds on the limestone in the shingles.It does matter how much an asphalt shingle cost eventually they will all get it.
    We us ethe same method as Michael with outstanding results.


  7. Markf

    Markf LawnSite Senior Member
    Messages: 406

    Thank you for the advise. My own home is experiencing this as well. And after reading this it makes sense because it is only on the north side.
  8. jeremy067390

    jeremy067390 LawnSite Member
    Messages: 49

    thanks thats awsome. any luck with this on gutters? i use a product from xterior called gutter zap now and a long a#$ brush. works great but i have to order it.
  9. 1MajorTom

    1MajorTom Former Moderator
    Messages: 6,073

    Very interesting. I've seen lots of roofs that have that staining, and I've always wondered what caused it. I too thought it must be "cheap shingles".
  10. Grass Man

    Grass Man LawnSite Senior Member
    Messages: 272

    .... Thanks for the info :).


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