Dark streaks, black stains, and green patches on roofs in Jacksonville are almost always caused by algae (Gloeocapsa magma), moss, or lichen — not dirt. These organisms feed on limestone filler in asphalt shingles, gradually degrading them and shortening roof life. Soft washing — low-pressure cleaning combined with specialized biocidal solutions — kills these organisms at the root and restores the roof's appearance without the granule loss and shingle damage caused by high-pressure washing.
Roof soft washing in Jacksonville costs $250–$450 for a 1,500 sq ft roof and $350–$600 for a 2,500 sq ft roof. 42 of 42 verified providers in Jacksonville offer roof soft washing as a standalone service or bundled with house exterior cleaning. Service covers the Jacksonville metro area including Northeast Florida, St. Augustine, surrounding areas. Never allow any provider to pressure wash an asphalt shingle roof — the Asphalt Roofing Manufacturers Association (ARMA) explicitly recommends against it. Only soft wash is appropriate.
After soft washing, treated algae and moss may not disappear immediately — biological material dies and washes away gradually over the next few weeks of rain. This is normal and expected. The roof will continue to lighten for 4–8 weeks following treatment. A second visit is rarely needed. Many Jacksonville homeowners schedule roof soft washing every 3–5 years or as soon as dark streaks reappear.
42 of 42 pressure washing companies in Jacksonville offer roof soft washing options.
Serves Jacksonville, Florida, Orange Park, Florida, Neptune Beach, Florida, Atlantic Beach, Florida, Jacksonville Beach, Florida, Ponte Vedra Beach, Florida, Duval County, Florida, Westside Florida
How much does roof soft washing cost in Jacksonville?
Roof soft washing in Jacksonville costs $250–$450 for a 1,500 sq ft roof and $350–$600 for a 2,500 sq ft roof. Larger or steeper roofs run higher. Bundling with house exterior washing usually saves $50–$100. Compare quotes from 42 providers in Jacksonville for your specific roof size and pitch.
Is pressure washing safe for my roof in Jacksonville?
No — high-pressure washing on asphalt shingles strips protective granules, voids manufacturer warranties, and can force water under shingles causing leaks. The Asphalt Roofing Manufacturers Association (ARMA) recommends against pressure washing shingle roofs. Soft washing is the only appropriate method. If a Jacksonville company recommends pressure washing your shingle roof, it's a significant red flag.
What causes dark streaks on my roof in Jacksonville?
Dark streaks on Jacksonville roofs are almost always caused by Gloeocapsa magma — a blue-green algae that feeds on the limestone filler in asphalt shingles. Green patches are typically moss. Black or dark areas with texture are often lichen. All three are killed by soft washing solutions. Left untreated, they can significantly reduce shingle lifespan by degrading the granule layer.
How often should I have my roof soft washed in Jacksonville?
Most Jacksonville roofs benefit from soft washing every 3–5 years, or sooner if significant algae streaking appears. Homes in shaded, humid, or heavily treed areas may need cleaning every 2–3 years. After soft washing, results typically last 2–4 years before biological growth visibly returns. Some Jacksonville companies apply preventive zinc or copper strips after washing to slow regrowth.