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.
Scrub the rust away using a stiff, wire brush. This will remove flaking rust and as much of the surface rust as possible. You won't be able to get all the rust off if the rust is extensive. Wash the metal roof using trisodium phosphate in water at a ratio of 1 cup TSP per 1 gallon water. You can wash it by hand, using a sprayer attachment to a garden hose or a power washer. A power washer may remove more of the rust for you.