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Question DetailsAsked on 1/18/2012

Black Algae, Mold on do you remove it? Is a specialty contractor needed?

Asphalt roof has dark streaks in it. Internet reseseach indicates its a air borne or animal transmited spore that jumps from house to house. Not only unsightly but can cause premature failure of a roof. Are there specialty contractors that perform this type of work?

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Any reputable roofing contractor can clean the roof for you. If it is really bad there is only so much he'll be able to do without possibly damaging the shingles. There are specialty chemicals sold by roofing supply companies that do well. A 50/50 mix of bleach and water has been the standard for years though many environmental and health people frown on it because of the chlorine content. I still use it from time to time for small areas. Large sections would be better dealt with using chemicals deigned for killing the mold/mildew on the roof. If you are the do-it-yourself type most roofing suppliers will sell you the chemicals over the counter. Just follow all of the safety and warning guidelines.

Todd Shell
Todd's Home Services

Answered 8 years ago by Todd's Home Services


It is never smart to power wash your shingles as most companies will try to sell you. Those black streaks are "roof wrinkles"Usually what your seeing one the black streaks is where water travels the most. That in turn removes more shingle granules than other areas of the roof. The reason it's black is cause your seeing the asphalt base under neath the granules. I highly doubt it's black mold, just your roof starting to show it's age.

Answered 8 years ago by Ilroofing2498

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