Roof moss control
Cleaning off moss is important to promote longevity of your roof, which protects the rest of your home. Moss growth will cause roofing materials to deteriorate because of the moisture it holds promotes rotting of roofing materials, creating dams in valleys causing water to back over flashing.http://bryophytes.science.oregonstate.edu/page14.htm
Cleaning methods we use are dependent upon the type of roofing material. We recommend against pressure washing most roofing materials (IE wood shake, wood shingle, asphalt based materials and EPDM roofing membranes). We use air and brooms on these materials to gently remove moss and debris. We also pressure wash concrete tile, clay tile, metal and slate type roofs.
Moss control is accomplished via chemical treatment. Potassium acid of fatty acids are somewhat effective on small infestations. Bleach (sodium hypochlorite) is very effective at eradicating moss infestation while minimizing environmental effects according to http://bryophytes.science.oregonstate.edu/page24.htm#potasalt . Zinc sulfate is very effective for control of moss and lichens over extended periods.