Dark stains on shingles?

snipped-for-privacy@mucks.net wrote in news: snipped-for-privacy@4ax.com:

zinc or copper strips. May have to go to a real building supply place for them.

Black Algae probably

Household bleach will do in most of that stuff. That was on a sidewalk. Bleach ain't gonna hurt that.

If you get any ideas, DON'T PRESSURE WASH A ROOF. The only people that will recommend that are people that do it for money and people that have done it.

Bleach,sprayed on in a garden sprayer, Bleach kills mold

SpraynForget has worked well for me.

That looks like it might work. Results show after a few weeks. Needs no scrubbing or rinsing and lasts for months.

Thanks

snipped-for-privacy@mucks.net wrote in news: snipped-for-privacy@4ax.com:

While I agree with what they say is the problem, they are trying to rope you in to keep buying the stuff.

"A standard practice should be to clean your roof and then apply a preventative such as Spray & ForgetTM every 18-24 months"

"Adding a roof algae/moss prevention program to your ..."

Zinc/copper strips will stop it as long as there is zinc/copper on the strips.

Anytime reroofing is done, Algae Resistant shingles should be used. Might even be standard across mfgrs by now.

And BTW, the best leak prevention program is to stay the hell off the roof.

I would never consider cleaning the roof if it involved any physical pressure on the grains in the shingles. The above product does not require scrubbing or rinsing. It only requires a time period for the results to show.