Dennco’s got different formulas for cedar, composition (asphalt) and tile.
Because cedar is the most absorbent, our treatments will keep moss off a cedar roof for 5 years.
Composition and tile are less porous than natural wood, so the best we can do is 3 years moss free.
There are several other moss control products out on the market, but we choose not to use them for several reasons. They’re not environmentally friendly, they corrode your roofing components, and lastly are not backed or warrantied by the application manufacturer.