Get Rid of Black Streaks on Your Roof

There may be something on your roof this summer, and it’s not Santa and his reindeer showing up for Christmas in July. Many homeowners in humid climates (like Maryland’s) are dealing with black streaks spreading across their roofs. Although many dismiss it as stains resulting from dirt, soot or mold, the problem is more serious. In today’s post we’ll tell you all about it.  Including how to remove it, and how to keep it from coming back.

What are these Black Streaks?

Those black roof stains are actually a bacterial growth. It is often called blue-green algae, but in fact it is a form of cyanobacteria known as gloeocapsa magma. Spread by airborne spores, the bacteria find favorable conditions on roofs, especially those with asphalt shingles. The shingles contain fiberglass and limestone, which is ultimately food for gloeocapsa magma. Unnoticeable in its earliest stages, the bacteria may have been growing for two or three months by the time homeowners become aware of it. Growths are most likely to affect the north side of roofs, as they receive the least sunlight and typically accumulate the most moisture.

What Does Gloeocapsa Magma Do?

Gloeocapsa magma’s biggest initial impact for homeowners is the eyesore it creates. The dark streaking is unattractive and can significantly lower your curb appeal. As your property value plummets, some homeowners have even had their insurance policies cancelled due to the bacterial buildup. If left untreated, more serious problems can arise. For example, your shingles might weaken or decay from the bacterial feeding. This, ultimately, makes the roof more susceptible to damage from the sun’s UV rays.

Eventually, airborne fungus interacts with the bacteria to create lichen, an invasive organism that can cause shingles to separate. This leads to roof rot and damage to roof supports and weather sealing. Additionally, lichen growth encourages accumulations of moss, which, over time, bring about serious structural damage.

What Can You Do to Fight these Stains?

There is a silver lining for homeowners dealing with black streaks. The stains are not permanent, and they can even be prevented from returning. Various chemical solutions can remove the bacterial growth, although cleaning on your own is not advised. In addition to the obvious physical dangers of working on a roof, improper cleaning could cause further damage and DIY approaches may void warranties or insurance policies. Instead, opt for professional roof cleaning by licensed and insured experts, like those at D&L Enterprises. We offer a variety of power washing and pressure washing services throughout Maryland and can clean your black streaks without damaging your roof.

Scheduling an annual power washing will help prevent the problem from recurring. But for additional protection, you may want to consider installing strips of copper or zinc below the shingles nearest the roof’s peak. Leave at least two inches exposed, so that with every rain, bacteria-killing molecules from the metal will wash down your roof.

At D&L Enterprises, we understand the importance of a clean roof. We have been providing customers in Central Maryland with safe and trusted service for more than three decades. Give us a call today to discuss any power washing or pressure washing services for your property.