Those black streaks are actually roof algae called gloeocapsa magma. You may have heard them referred to as blue-green or black algae. Algae is another form of mold and is a solid deposit of dirt and spores. Roof algae will weaken the shingles over time.
The algae cells also create a pigment that makes the roof less reflective which cause it to absorb more sunlight. This absorbed sunlight is transferred into the house as heat which can raise your cooling costs. The algae often team up with a fungus to form lichen and then moss follows that. Moss growth can cause the leading edges of the shingles to lift or curl, which increases the risk of the shingles blowing off with higher winds. Severe moss growth can cause moisture damage to the roof deck and can lead to your roof eventually leaking.
Can Roof Algae Cause Problems With My Roof if Left Alone?
Often times you will see someone say that algae on a roof is only an aesthetic issue and does not cause damage. That is partly true. The algae alone may only cause ugly black streaks, but when the algae eventually teams up with a fungus to form lichen and then moss, that moss is what causes the shingles to hold constant moisture and weaken. All these events, over a series of years, will lead to a need for costly roof replacement.
Can I Just Pressure Wash My Roof?
Pressure washing can damage shingles, so we clean our customer's roofs with a softwash technique that is recommended by the Asphalt Roofing Manufacturers Association. If you go to hire a pressure washing company that wants to actually pressure wash your roof, run the other way. Only the softwash technique is an approved way to remove the black streaks, moss, lichen, or anything on shingles.
Why Do Some Areas Have More Black Streaks on Roofs than Others?
In Central Arkansas we see a lot of black streaks on the north-facing and shaded parts of roofs and siding. Moss thrives in areas with a lot of moisture, the parts of the roof that get the least amount of direct sunlight will be the ideal place for the moss to grow. You will notice that houses shaded by trees will also see a lot of growth.
Softwashing your roof will help your roof perform the way it was intended! Call Pressure Perfect today to get your roof cleaned before it becomes a real problem.