There has been significant interest in washing roofs lately, including a lot of questions about what products to use when washing roofs and how to remove those black streaks and stains (mold algae also known as ‘gloeocapsa magma’). Washing roofs to remove these stains will significantly affect the look of any home. In the past, the only way to get rid of them was to replace the roof. It has been estimated that as much as 50% of all roof replacements have been done because of the appearance of the roof stains and not actually because of its functionality.
These roofing stains are impossible to remove without the right roof cleaners. Caustics are inexpensive and very effective for killing mold. Bleach is used most often when washing roofs, but sometimes with disastrous results. GAF roofing says that the use of bleach when washing roofs immediately voids any warranty on an asphalt roof because it breaks down the composition of the shingle. We have heard of contractors resorting to 12% bleach concentrations, but many experts believe that this kind of roof washing can result in roof failure within a short time frame.
When we are power washing roofs for customers, we use the following method: First, using an X-Jet, we wet the roof slightly to cool it down. Second, we apply QwicClean’s Roof cleaner to the shingles, from the ground, using an X-Jet. We allow the roof cleaner to work for about 15 minutes before we begin power washing. (Note: Roof Brite costs as little as 70 cents per gallon, which is less expensive than bleach!)
Walking gently on the roof while washing, we clean the roof using very light pressure – about 300 PSI. We are very careful to avoid knocking off gravel from the surface of the shingles when washing roofs. When we meet up with a tough stain area, we use a very soft scrub brush with a 5′ handle and gently scrub this area. Finally, we rinse the roof surface well. Rinsing can be done from the ground using your X-Jet again.
Steep roof cleaning jobs require special gear to prevent falls. After all, a good roof cleaner can make any surface pretty slippery. A chicken ladder along with a roped harness is one way to make it safe to move around when cleaning roofs.
Be very fussy on the street side of the roof, homeowners are looking for “curb appeal”, so spend the most time where it counts the most.
Once the roof washing is done, there are two other services we can offer our customers. For an additional fee, we will treat their roof with Bio Barrier, a special formulation from QwicClean that prevents new algae spores from sticking to that clean roof. Instead, the spores move on to the neighbor’s roof where they grow, turn black, and create future roof cleaning jobs.
For another charge we will clean the gutters (inside and out). Being careful not to get any roof cleaners on the house paint (to avoid streaky clean spots) we scoop and rinse out the gutters and clean the outside surface with Gutter Zap. This can be done from the ground with an X-Jet or it can be done by wiping the gutter surface with a rag (and Gutter Zap).