You've pulled into your driveway, and for the first time, you notice the black streaks on the roof of your home. We'll tell you what these black streaks are, where they came from, and what you can do to restore your roof to its original condition.
Like 90% of homeowners in NJ with a roof that is more than 4 years old, you may have some sort of growth on your roof. The substance on your roof is organic, and there are three types that flourish on roofs here in Monmouth and Middlesex County.
Please see the pictures on the left. Those are the black streaks in the leftmost image. There is a solution as you can see from the "after" picture on the right. It shows the same property after having us professionally clean their roof.
All "before and after" images on this website are actual photographs taken at our client's properties; these photos have not been altered in any way.
What are the blackish streaks on the roof?
The streaks are a bloom of a plant-based bateria called Gloeocapsa Magma, which has gained notoriety in the Eastern United States and is spreading westward. This type of cyanobacteria is responsible for causing the black stains on roofs. The bacteria may be carried by the wind, and settle on your roof where it thrives on moisture and calcium carbonate. The black streaks begin to show when the bacteria develop a dark UV-protective coating.
So the bacteria is a type of plant that feeds off the moisture and calcium carbonite in your roofing shingles. You may have noticed the growth is worse where your roof is in the shade, or on the north-facing side. It's because these areas are more shielded from the sun and retain water for a longer period. Another related problem is mold, which also feeds on the carbon and tar in your shingles. And other plant-based threats exist. Add it all up, and it means an even greater amount of roofing shingle is being slowly consumed.
Your roofing shingles will not be destroyed overnight, since the degradation happens slowly. We have even heard it argued that a professional roof cleaning is desirable for purely asthetic reasons. It may be true, but to ignore the problem is a risky proposition. We will not wager a $20,000 - $30,000 roof that the organisms eating it are benign. Cleaning your roof for a clean look and a nice curb appeal may be an additional benefit of getting rid of the infestation.