Some facts about a mossy roof 

Many years ago we discovered that modern shingles would be prone to serious attack by algae, moss, fungus and black stains. Shingle formulas were slowly changing to include extenders like limestone, cellulose and various wood products. Less and less petroleum and felt ingredients were being used. The unexpected (not to us) result was destructive algae infestation (black or green shingle stains) on millions of homes all across America. This biological growth also attacks wood shakes and clay tile roof material. Shingle manufacturers did not intentionally create this side effect. However, moss, algae and fungus are consuming and decomposing your shingles, just as a fallen tree is decomposed in the forest. The simple fact is that roof material now contains nutrients that algae, moss and fungus like to eat. We knew that shingle formulas would not be changing back to the other stuff (non-algae food), so we designed a safe and effective cure for this widespread and costly problem. Roof Reviver™ safely kills this biological growth without harming the roof. We even went one step further and had our products tested by the finest shingle makers in the world like GAF and Elk. Successful treatment involves understanding the cause of the problem, not just splashing toxic chemicals on the roof. An equally challenging problem was that algae and fungus are able to flourish on shingles as we stand helpless on the ground. After all, a roof is not the safest place to work. With this in mind, we developed affordable pumps that let anyone apply Roof Reviver™ from the ground. Once Roof Reviver(TM) has been applied to moss, algae or fungus, no other work is required. Rain and wind will quickly finish the rinsing process for you. 

Moss, algae and fungus derive nutrition from cellulose found in nature, and in modern roofing. If left untreated, moss will quickly cause permanent roof damage. Roof Reviver(TM) safely removes this biological growth without harming the roof. Guaranteed!