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Question DetailsAsked on 6/21/2011

Is roof cleaning necessary?

Roof cleaning - is it necessary and/or safe?  My roof is in shade much of the day, and has black areas which I guess are mildew or something similar.  I have heard that adding a copper strip can help to prevent this problem.  Any info?

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4 Answers


Yes cleaning is essential to the investment of your roof. The black stuff you see is Black Spigea Algea. It feeds on the granules of your asphalt shingles. If you leave it untreated you will find yourself replacing the shingles much sooner than necessary. I would suggest that you contact a local roof cleaning/restoration company to remedy this for you. Its typically not very expensive depending on your roofs elevation and pitch.

Answered 9 years ago by Guest_91093355


Have a roofer install ZINC strips along your ridge line. This is a better fix than roof cleaning

Answered 9 years ago by Onlythebestbuilder


Roof cleaning is not necessary. You will replace your roof shingles long before the algae has any chance to do damage to your roof shingles. The only benefit to cleaning your roof is a cosmetic one. Roof cleaning can make your algae stained roof look almost as good as new.

Redline Roofing

Answered 9 years ago by Redline Roofing


The answer is yes and no. This really depends on the type of roof and the reason for the streaks. If the streaks are an algae then killing that vegetative growth may be encouraged. If the black streaks are actually granual loss then washing may actually cause more harm than good.

What is important is that high pressure is notused to clean the roof. A pressure washer by a trained professional using low pressure is ok. However a pressure washer by a non-roofer can cause you to need a new roof!

Cedar is one of those roofs that we recommend cleaning on a regular basis.


Answered 8 years ago by ReliableAmericanRoof

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