What Those Black Streaks on Oakton and Fair Oaks Roofs Really Are

If you've noticed dark streaks running down roofs in Oakton, Fair Oaks or Greenbriar, you're not imagining it. They're one of the most common questions we get this time of year.

The streaks are algae. It grows on shaded, damp shingles and spreads from roof to roof, which is why you often see a whole street with it.

A few things homeowners should know:

1. It isn't dirt, and it won't wash off in the rain.

2. Never pressure wash a shingle roof. High pressure strips the granules that protect the shingles.

3. A low-pressure soft wash with a cleaning solution removes the algae safely.

4. Trimming branches that shade the roof helps keep it from coming back.

About the author: AllPro PowerWashing is a locally owned exterior cleaning company based in Manassas, serving homeowners across Oakton, Fairfax, Chantilly and Northern Virginia. Questions? 571-364-4466 or allpropowerwashingllc.com