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We are power washing our roof and amazed by the amount of mold growth on it. It has been 4 years since last power washed, when it was painted. We are on catchment. We are using only water for power washing (no soap etc) and diverting all the wash water away from catchment. Is there anything that can safely be used to retard mold/mildew growth on roofs that are used for catchment/drinking water? ie. something applied and washed off that would kill the mildew so it does not grow back so quickly, but not be harmful for catchment/drinking.
Mahalo!
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I have always wondered about what people used to re-paint metal roofs. I know that any number of products would be labeled as fine for metal. The original paint must be a baked on enamel and has a nice tight, smooth surface which would impede anything sticking or growing on it. Over time though the sun will start to oxidize the surface creating a rougher surface which allows for catching things that mold likes to grow on. I don’t think that there is a reasonable method for a homeowner or most contractors to get that same quality again.
Nothing that will clean or kill mold would be good in the catchment tank but there any number of cleaners, mostly with bleach, that help with mold. If you have plenty of water just keep it diverted for a week or so and it should be fine by then. And, if you have one in the system a carbon filter is supposed to take the bleach out. I throw a cup or two in my tank every few months.
Jay
Jay
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Bleach will destroy a metal roof. Make sure the paint is completely intact before you use any bleach.
Puna: Our roosters crow first
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Back in IL, on non-catchment shingle roofs, we installed zinc or copper strips at the ridge-line to deter moss growth...
Would not recommend copper for a steel roof (probably would increase galvanic corrosion), but zinc would seem to be OK for the roof.... have no idea how much zinc would be added to the water....a little would probably be OK...
