My roof cleaning is all done by hand rather than pressure washing. This allows me to be very selective about which areas of the roof get cleaned. The benefits to this approach: Less abrasive cleaning touching only 10% to 20% of the roof; No water = no leaks.
Once I remove the moss I apply a generous amount of moss treatment, (zinc sulfate) to the roof to kill the roots of the moss and keep it from coming back.
Preventative – with new roofs or newly cleaned roofs, the best, least abrasive, most cost-effective method to keeping a clean roof and prolonging its lifespan is to keep it treated and avoid roof cleaning altogether.
So, have me out once/year for moss treatment. Tip: Bundling this service with your window or gutter cleaning will give you a discount.