Cleaning black stains off Shingle Roofs

Thanks to all of you that helped me with my roof cleaning project.
I was going to hire someone - or rent a pressure washer. Instead - I made a solution of 10% bleach and 90% water - kept it mild in case it dripped on our plants. I sprayed it on the roof with a small pump sprayer - let it sit a while - brushed it with a long handle brush I use to wash my camper - then hosed it off with a regular garden hose - low pressure.
All of the stains disappeared - I checked the gutters to make sure I was not washing off the shingle "grit" - I was not. One day later - the roof looks like new. I plan to go up today and do it again on the spots that I missed.
Thanks to those that gave me the bleach advice.
Harry
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I understand you can install copper wire or flashing near the top of the roof. The rain water will carry the copper down over the roof and poison the mold. Anybody every try this? Does it work?
Mark
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I've used 10-inch wide pure sheet zinc near the roof ridge. Works quite well, and I understand this is a common approach. Doubt that wire would work, but sheet copper might, as the brick walks under my copper gutters' drip line have bare spots where no mold grows.
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Wait a few months. The black stains will return. They may be unsightly, but you are doing more damage using the brush. When you replace your roof, get mildew/mold resistant shingles.
On Sat, 05 Mar 2005 12:31:55 -0500, Harry Everhart

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Thanks for all your help and tips. The roof looks great now. It was not washed in 10 years - so if the grime takes that long to accumulate again - I will be happy. I plan to replace the shingle in 5 years. I used a very soft bristle brush - like a car brush. Just enough to agitate the sodium hypochlorite solution. I also used a garden hose to rinse - not my pressure washer. I have lots of big live oak trees and long needle pines shadowing my home - their drippings seems to cause the problems. I am sure they will come back. Harry
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This works with just about any metal, but as a preventative and not for an older roof. I have "Shingle Shield" installed on my roof, a strip of zinc. My roof is streak free for 14 years.
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============================================Interesting Thread.....
I presentaly have this problem...lucky for me the problem areas face the rear of the property....not visable from the road but sitting by the pool or down by the garages it looks like hell....
Guess I will live with it a "little" longer but when I reroof I will install dark shingles...IF I live that long...lol
Bob Griffiths
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