Here at Paint Your Roof we are not here to scare you into washing your roof, as a matter of fact unless your roof is severely mold and algae ridden, it shouldn't affect the longevity of your roof at all. (At least that is what the shingle manufacturer’s stand behind). My only goal is to give you the look your home should have, and keep that fresh look. And finally you can trust your roof with me,  Dave because I do the work myself. (I even create and maintain this website) and has been an actual roofer for the past 30 years. Check it out for yourself.