Everything You Need to Know About Algae Discoloration — A Guide for Your Roof

If you have dark streaks developing on your roof, you might think it’s due to moss, fungus, tree droppings or just accumulated dirt. Here in our area of Florida, this black/brown discoloration is often caused by algae, and it can affect almost any type of roofing material including asphalt shingles, tile, slate, shakes, composite roofing and even metal.

Why Algae Growth Occurs on a Roof

Roof algae is a plant-like bacteria whose spores are carried in the air, so it easily spreads from rooftop to rooftop where it thrives thanks to our hot, humid climate. The most common type of roof algae – gloeocapsa magma – shields itself from the sun’s UV rays by producing a pigmented sheath that results in the dark discoloration seen on your roof. Algae growth may appear as just a few small dark spots at first, but as it gets established, extensive brownish-black streaking can develop quickly.

Does Algae Harm a Roof?

Concern that algae might damage your roof is understandable, especially if the streaking is severe. Fortunately, algae growth that’s dealt with promptly shouldn’t harm your roofing material. If you have a light-colored “cool” roof, wide-spread algae growth may affect its reflectivity, though. Scheduling professional roof cleaning is the safest and most effective way to deal with an algae problem.

Guide to Algae Discoloration

How Professional Roof Cleaning Can Solve Algae Discoloration

A skilled roofing professional can lighten the algae discoloration on your roof by applying a solution that meets your roofing material manufacturer’s guidelines. An experienced pro won’t use a pressure washer, vigorous scrubbing or harsh chemicals, since doing so can damage the surface, cause the loss of shingle granules or even jeopardize your manufacturer’s warranty. By following the manufacturer’s recommended process, a pro can clean your roof thoroughly and safely so there’s also no risk of harm to your family, pets or landscaping.

Tips to Prevent Future Algae Growth

In between professional roof cleanings, you can take these steps to keep algae growth under control:

  • Keep overhanging tree limbs trimmed back to let sunlight reach your roof.
  • Keep your gutters cleaned out so rainwater can drain freely, and make sure downspouts serving an upper roof don’t drain directly onto a lower roof.
  • Have debris buildup cleared away regularly using downward airflow from a leaf blower or similar equipment

To schedule roofing cleaning to rid your Naples home of algae discoloration, contact us today at Kelly Roofing.

Read: What your Commercial Roof Maintenance Should Include