Because of this being a rain wash-down process there is no longevity warranty. The more rain the roof receives, the sooner the product goes away. On my own roof it lasted for two or three years before we started seeing moss coming back. How long yours lasts will depend on severity, pitch, shade and the presence of debris.

Because we have treated so many comp roofs, we have learned that they are all pretty much the same amount of work (which is not very much) and so have started charging them at flat rates without doing individual bids. Included is debris and gutter cleaning as needed, as well as clean-up. You should plan on around $295 give or take about $50. Some of the very straightforward ones are $225 and if we cannot do yours for $345, we will call and discuss some options with you..