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Can the staining on my stucco, which is adjacent to a metal roof, be the result of galvanic corrosion? Mildew cleaner nor scrubbing will remove it. See image below.
6/7/2021
This appears to be mildew / biological growth. Watts Products makes some good products for cleaning such things. You can also use water and detergent / TSP or something like Wet N Forget. Always try it on a small roof area first to make sure the finish isn't damaged. I would not expect it to be.
Isaiah Industries, Inc.
6/7/2021
I have already used a mildew remover and tried scrubbing it with a brush. any chance it is metal from the roof interacting with the stucco?
6/7/2021
It does not at all look like that and I have also never heard of such a thing. There are some more aggressive mold cleaners such as RMR-86 but I would test them first. You might also look into "soft washing" from a commercial power washing company.
Isaiah Industries, Inc.
6/7/2021