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Roof Streaking: Time for a new roof?

What are those black streaks on your roof? Dirt? Mildew? Burnout marks from Santa Clause? It actually is algae, gloeocapsa magma to be exact- otherwise known as blue-green algae. So why is it black? This alga actually has a darkly pigmented outer layer that protects it from UV rays, causing those dark streaks on your roof. These little bacteria build up over time as they feed on moisture and calcium carbonate.

All about Algae

Gloeocapsa thrives in environments with high humidity and temperatures, which makes the south a perfect place. The spores are airborne, giving them the ability to be carried by the wind and animals and allowing them to spread throughout the neighborhood. It's also a growing problem! Asphalt shingles were originally made mostly of asphalt, which is an oil-based product also containing felt material. As a cheaper alternative, manufacturers began using fillers like fiberglass and crushed limestone in their shingles. Algae also love to munch on that limestone filler.

You'll usually see algae growth in the northern part of your roof, as this area will usually be the most shaded area as the sun makes its way through the sky. The shade allows for moisture to hang around, allowing the perfect spot for algae growth. Gutters draining (or overflowing) directly onto the roof or overhanging limbs can also contribute to algae growth, as this can dampen the ability for the roof to dry. 

Removal or Replacement?

While there are some ways to remove and prevent algae streaks on your roof, one of the easiest ways to confirm its presence is by taking a look at the other homes around you. You're likely to notice buildup on their northern side of their roof as well since the air and wildlife passes over their homes too.

  • Chemical Cleaning: There are a few different ways to clean your roof streaks using bleach-based cleaner products, but more often than not, these products are only designed to lighten the stains rather than preventing them from coming back and can be harmful to the environment. Some chemical cleaning can also void manufacturing warranties, so we do not usually recommend cleaning.
  • Physical Debris: One cause of algae buildup can be excessive leaves and other debris piling up on your roof and gutters. Trotter Roofing offers gutter cleaning and maintenance to keep your roof from becoming a streaky mess.
  • Roof Replacement: Since these algae stains form due to the limestone presence found in fillers in asphalt shingles, one of the best ways to get rid of and prevent streaks is by changing your roof material altogether. We use shingles that contain high levels of copper, which fight against algae growth. 

Roof Replacement

If your home is susceptible to humidity and high temperatures, changing roof material can be the most efficient way to say goodbye to roof streaks. Trotter Roofing offers a variety of roof types, ranging from shingles, to tile, to metal roofing. Whether you need a new roof with shingles to start managing you're algae properly, or want to change material all together, call Trotter Roofing today to speak with our professionals about upgrading your home's first line of defense from the elements.