WANTED
for vandalizing Florida roofs
BLACK STREAK · NO. 0418
Gloeocapsa magma
a.k.a. "roof algae," "those black stripes"
- Last seen
- North- and west-facing roof slopes
- Diet
- Limestone filler in asphalt shingles
- Travels
- Roof to roof, on the wind
- Damages
- Curb appeal, roof life, HOA letters
Reward: a clean roof for 18–24 months
Why roofs streak here
Those black stripes aren't dirt. They're alive.
The dark streaks on most Florida roofs are a bacteria called Gloeocapsa magma. It feeds on the limestone in shingles and thrives in our humidity. Pressure washing just moves it around. Soft washing kills it.
High-pressure washingCan strip granules, crack tile and void some shingle warranties. Algae comes back fast.
Pressure Time soft washLow pressure plus a cleaning solution that kills growth at the root, so it stays clean longer.