Homeowners in hot, humid areas are often encountered by the mysterious and hideous sight of black streaks on their shingled roofs, especially during spring. These unsightly black streaks are usually caused by black algae and roof mold.
While not immediately damaging, roof mold is simply ugly and can reduce the resale value of your home, while also causing your shingles to age prematurely. The algae can also cover your entire roof, giving it a dull and unappealing look, while also trapping rain water that can then slowly seep into the shingles and cause damage. Here is a look at how you can prevent and remove black algae and mold from your roof.
Preventing roof mold
The easiest way to keep those black streaks off your roof is to install strips of copper or zinc coated sheet metal just below the ridges on both sides of the roof. Zinc and copper molecules are toxic to algae and moss, and will be washed down the whole roof every time it rains, killing any roof mold that is trying to get a grip on your shingles.
Alternatively, have algae resistant shingles installed, especially if you live in an area highly susceptible to roof mold or are simply tired of cleaning black steaks off your roof every spring.
These shingles contain tiny copper pellets that act as deterrents to roof-algae, keeping your roof nice and clean. The shingles also often contain ceramic granules that provide an effective sunscreen that reflects UV rays away from the roof surface, protecting the shingles from places like Conrad Roofing Of Illinois from sun damage.
Removing roof mold
If your shingles are already infested with ugly roof-algae stains, chemical cleaning could provide a safe and simple way to eradicate them from your roof. Chlorine-based bleaches - though effective and fast at killing mold and lichen on your roof - might damage and discolor asphalt shingles due to their high sodium content. Chlorine would also drain off the roof and seep into the soil, killing plants and contaminating underground water sources.
Go with oxygen bleach instead, as it is toxic to roof mold but environmentally friendly and less harsh to your shingles. A mixture of oxygen bleach and water should be sprayed on all stained areas and given time to take effect. A water hose could then be used to rinse off the dislodged roof mold, or you could just wait for the spring showers to rinse everything off.
A solution of trisodium phosphate and bleach could also work wonders against roof mold and black algae, while also helping to remove other stains on your shingles.