Elastomeric roof coatings are applied thicker than paint. These elastomeric roof coatings are used for roof leaks repair. An elastomeric roof coating seal roof leaks, saves and extends the life of old roofs. Elastomeric roof coatings are an excellent choice for roof leaks repair.
How to Clean Algae and Moss from a Roof. Apply the bleach solution with a garden sprayer. Let it stand on the surface for about 20 minutes, then rinse it off with spray from a garden hose. Don't let the bleach solution stand on the roof for more than 30 minutes or so without rinsing.
Once the roof is clean, you can prevent the algae from coming back by installing a 3-inch strip of copper at the top of the roof. Every time it rains, a tiny amount of copper will wash down on the roof. Copper is a natural biocide, and the algae will not grow in its presence.