What Causes Black Streaks on Roofs in Georgia?
If you've noticed dark streaks running down your roof, you're not alone. In Georgia's warm, humid climate, these streaks are extremely common — and they're not just dirt.
The Culprit: Roof Algae
Those black streaks are caused by Gloeocapsa magma, a type of algae that feeds on the limestone filler in asphalt shingles. It spreads easily in humid conditions and thrives on north-facing and shaded roof sections.
Why You Shouldn't Ignore Them
Beyond hurting your curb appeal, algae growth can hold moisture against your shingles over time. Cleaning it removes the staining and helps keep your roof looking its best.
The Safe Way to Remove Them
Never use high-pressure washing on a roof — it can strip protective granules and force water under the shingles. Instead, professionals use soft washing: low pressure combined with specialized solutions that break down algae at the source.
Keep Them From Coming Back
Because soft washing treats the algae rather than just rinsing the surface, results last much longer — often a few years before streaks return.
Peak Exterior Solutions safely soft-washes roofs across Metro Atlanta. Call (404) 202-5439 for a roof cleaning quote.