Black streaks on the roof

Why are there black streaks on my roof?

In Indiana, black streaks on a roof is the result of a perfect soup of climate and science.

The problem is more than just aesthetic. Those streaks are evidence of a type of algae that not only poses issues with a roof’s viability but can create health hazards as well to not only the residents, but pets and other wildlife.

Most common culprit of black streaks is a cyanobacteria known as Gloeocapsa magma, sometimes referred to by roofing professionals as blue-green algae.

While the photosynthesizing bacteria is generally blue and/or green in color, it becomes darker on roofs as it struggles to protect itself against the sun’s ultraviolet rays, not unlike many of the materials found in common asphalt shingles.

This type of nuisance began appearing several decades ago in the southeast, and all the way north to Canada.

Why are there black streaks on my roof?

Gloeocapsa magma, the origin of black streaks on the roof, is airborne and breaks down shingles by feeding off the product’s limestone content. Once the streaks appear, they will worsen until dealt with. If not eliminated, the algae will continue to compromise the shingles, eventually leading to a leaky roof.

Experts remind residents and homeowners of the potential health hazards with Gloeocaspa magma. Financial ramifications are prevalent, such as having to replace a roof well before the end of its life expectancy. There is also a negative effect on property resale value. Insurance companies cancel policies when learning of the presence of the algae. On residential properties, the bacteria has resulted in replacements of entire roofs and declining property value.

As algae grows darker to protect itself from the sun, the darkness causes excess heat absorption. This hits the homeowner’s pocket book with higher costs of utilities.

If you spot the signs of algae, it might be a good idea to consult with a professional. Some roofing contractors provide professional pressure washing services that help clean the problem off the roof before damage is permanent. Keeping the roof clean is the best way to eliminate black streaks from your roof. Call Re-New Roofing & Remodeling. today for a free inspection and estimate.