Opiniions on Roof Cleaners Please

Need to clean my roof - dark stains, etc. Looking at; - Roof-be-clean - RD-30 Roof Cleaner - Kleen-Roof I have done newsgroup searches, but nothing comes up on these particular products. Any experience with these? or any others that work?
thanks - jim
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Spam Me Knot wrote:

    Although I do not recognize the products you cite for cleaning roofs, I did use one along with the recommended bleach solution. It did clean the shingles when used with a pressure washer set at low pressure, but I finally gave up when I realized that unless ALL your neighbors also clean their roofs, your roof cleaning is only temporary. I believe it is mildew and fungus that is the cause of the stains, and unless you can stop the wind blown transfer from other roofs, you will soon be back as square one.
    Perhaps some day someone will make shingles with an additive that will prevent such stains? For what it is worth, I have watched roofs that used the zinc strips to prevent this from happening, and even it is not completely effective. It might help, but it did not completely stop them from occurring. After having gone to a light colored roof to reduce attic heat, I think my next shingles will be DARK in color so that the stains are not as visible.
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I use straight bleach with a garden sprayer. Get on the roof spray a section, wait a few minutes and then hose it down. For each section I start at the top and run down to the gutter otherwise you can get streaking. I have a light brown shingle, bleach does not seem to change the color at all. You should test a section first. This lasts for at least 2 years on the shaded part of the house and more on the southern exposure which kills the stuff from the heat. I do have a good brand of shingle(25 year type). They have been on the roof now for 22 years and all seems ok and I have done this every two years for sure in the last 10 years.
Make sure it is a calm day for wind as you are dropping bleach down the gutters and off sections with no gutters and you do not want the run off to hit the house and such. I am also stingy on the wash off in the sense that you do not need high pressure, just reduce the concentration down to a point that if dries with some bleach left, this inhibits future growth. i.e. you are not trying to remove all the bleach with the wash down.
Tom

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