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.
Lichen on roof removal? I have green lichen growing on one area of my north facing roof. The obvious thing is you do not want to scrub it, as that would damage the shingles, especially given the age of your roof. Zinc strips on the roof is supposed to help prevent if not stop the chance for lichens to grow on the roof.