You may already know this but if you look at rooftops there will not ever be mold or mildew down the slope of a roof below where the metal vents or pipes are. The rain water run off carries the zinc " galvanized " coating down the roof and it kills it. If you have a mold or fungus on the roof you can spray the very top of the roof with zinc and it will eventually kill all of it for pennies.

You may already know this but if you look at rooftops there will not ever be mold or mildew down the slope of a roof below where the metal vents or pipes are. The rain water run off carries the zinc " galvanized " coating down the roof and it kills it. If you have a mold or fungus on the roof you can spray the very top of the roof with zinc and it will eventually kill all of it for pennies.