Although tiles are made to be resistant and some newer models are even impregnated with anti-algae solutions, as the time passes by, they begin to deteriorate just like any other material. Permanent solutions against mold, algae and fungi are unfortunately not available, so cleaning operations in the spring are important, both aesthetically and practically.
A roof affected by mold, algae or fungi will present black or discolored streaks; check the north and the shadiest portions carefully. Over time, these factors can erode the roofing material and cause shingle damage and water leaks.
If you want to remove mold, algae and fungi from your roof, you will going to need more than just water. You must use a chlorine-based substance, a solution containing copper sulphate or a pre-fabricated professional solution, produced for this purpose. Please note: some of these substances are corrosive, so they should be used with caution and as instructed by specialists. In most cases it is best left to the professionals found here http://www.richardsonroofing.com to keep your roof sustainable.
Before starting the cleaning process, all the plants around the house must be sprinkled with water, so they do not absorb the substances that may be harmful to them. Apply the solution with a hand sprayer and let it work. Rinse using a garden hose. If necessary, repeat the process.
Another effective operation to prevent the formation of mold, algae and fungi is to cut the tree branches that pass over the roof; this way, you increase the exposure to sunlight.