Black Streaks on Orlando Roofs: What Removes Them

Drive any street in Orlando and you'll see it: dark streaks running down shingle and tile roofs, always worst on the north-facing slopes. That's not dirt, and it won't rinse off in the rain.

It's alive

The streaks are Gloeocapsa magma, an airborne algae that lands on your roof and feeds on the crushed limestone filler inside asphalt shingles. Central Florida gives it everything it wants — heat, humidity, afternoon rain and shade. Once a colony establishes, it spreads season after season, and the dark staining holds heat, which ages the shingle faster and works against your attic insulation.

Why pressure washing is the wrong answer

A pressure washer will strip the streaks — along with the granules that protect the shingle. One aggressive wash can take years off a roof's service life, and most shingle manufacturers explicitly warn that pressure washing voids the warranty. On tile, foot traffic is the hidden cost: every cleaning that puts a person on the roof cracks tiles you won't find until the next storm.

What works: soft washing

The method shingle and tile makers actually recommend is a soft wash — a low-pressure application of a cleaning solution that kills the algae colony itself. The streaks lighten immediately and rinse away over the following weeks. Because the colony is dead, not just shaved back, the result lasts two to four years instead of one summer.

How WashGrid does it differently

Our aerial system applies the soft wash from above — no ladders on your gutters, no one walking your tile. The property gets documented before and after, so you can see exactly what changed, slope by slope.

If your roof is streaking, request a free assessment. We review the roof from existing aerial imagery before we ever call.

For Orlando homeowners

Roof streaking is the most visible symptom of the algae cycle every Central Florida home fights. If yours is showing it, the fix is a professional roof soft wash — and the way to never see it again is a maintenance cadence, not a one-off. See how we care for houses on our residential exterior cleaning in Orlando page, or jump straight to residential maintenance plans.