Those Black Streaks Are Costing You Money
If your home in Conway has dark streaks running down the roof — the kind that look like water stains or shadowing but don’t disappear after rain — you’re looking at Gloeocapsa magma. It’s a cyanobacteria (blue-green algae) that lives on asphalt shingles, and it’s doing active damage right now.
Gloeocapsa magma feeds on the calcium carbonate limestone filler in asphalt shingles. As it grows, it consumes the material that gives shingles their durability and UV protection. The dark pigmentation the bacteria produces is a sunscreen — it allows the organism to survive Arkansas’s intense summer sun by blocking UV. This is the black streaking you see. And underneath that streaking, the bacteria is actively eating your roof.
Left untreated, Gloeocapsa magma accelerates granule loss, reduces shingle flexibility, and can shorten roof life by 5–10 years compared to a roof that’s cleaned on schedule. Most roofing manufacturers now recommend periodic soft washing as part of a maintenance program — some require it to maintain warranty coverage.
Why You Must Use Soft Washing — Not Pressure Washing — on Roofs
This is the most important thing to understand about roof cleaning: high-pressure washing destroys asphalt shingles. It’s not a matter of technique or being careful — the granules that protect shingles from UV radiation are physically bonded to the shingle surface, and high-pressure water strips them off. A pressure-washed roof loses years of life in one cleaning.
The correct method is soft washing:
- A cleaning solution (typically sodium hypochlorite at professional concentration plus a surfactant) is applied at low pressure to the roof surface
- The solution kills Gloeocapsa magma, moss, and lichen at the root level
- The dead organisms are rinsed away with low-pressure water (similar to garden hose pressure)
- No physical scrubbing, no high pressure, no granule damage
After soft washing, streaking disappears. Organisms that weren’t fully visible (early-stage growth) also die. Results typically last 2–4 years in Arkansas’s climate before retreatment is needed.
Moss and Lichen: More Serious Than Algae
In addition to algae streaking, many Arkansas roofs — especially those with significant tree canopy — develop moss and lichen growth. These organisms are more aggressive than algae:
Moss forms thick mats that hold moisture against shingle surfaces. This moisture accelerates granule loss, promotes wood rot in the decking beneath, and creates freeze-thaw damage in winter as trapped water expands. Moss also lifts shingle edges, creating entry points for wind-driven rain.
Lichen (the crusty, circular growth that appears gray or white) bonds directly to shingle granules with root-like structures called rhizines. Lichen cannot be physically scraped off without damaging the shingle — soft washing kills the organism and allows it to release naturally over several weeks as rain washes the dead growth away.
Moss and lichen require a stronger treatment concentration than algae-only cleaning. Properties with significant moss or lichen coverage should be assessed individually for treatment planning.
How Often Should Roofs Be Soft Washed in Arkansas?
Most Arkansas roofs benefit from soft washing every 2–3 years. Factors that shorten the interval:
- Heavy tree canopy overhead (shade prevents the UV exposure that naturally inhibits algae)
- North-facing roof sections (less direct sun, more moisture retention)
- Previous heavy moss or lichen infestation
- Proximity to water features, ponds, or heavily irrigated landscaping
Properties in heavily shaded environments may need cleaning every 18–24 months to stay ahead of regrowth.
Roof Soft Washing Pricing in Conway, AR
Roof cleaning pricing is based on roof square footage, pitch, height, and organism load:
- Single-story home (roof under 1,500 sq ft): $250–$400
- Two-story home: $350–$550
- Large home or complex roofline: $500–$750
- Moss or lichen treatment (heavy infestation): Additional charge based on coverage
Combining roof cleaning with gutter cleaning and house washing in the same visit produces bundled pricing savings of 15–20%.
Schedule Roof Soft Washing in Conway
American Services AR provides professional roof soft washing using appropriate chemistry and low-pressure technique that won’t damage your shingles. We serve Conway, Faulkner County, and all of Central Arkansas.
Call 501-289-5623 or visit americanservicesar.com for a free estimate.
Frequently Asked Questions
Will soft washing void my roof warranty?
Soft washing with approved methods and chemistry is specifically recommended by major shingle manufacturers including GAF and Owens Corning. High-pressure washing often does void warranties. Always use soft washing for asphalt shingles.
How long until the streaks disappear after soft washing?
Most algae streaking disappears during or immediately after the service. Heavier biological growth may take a few rain events to fully rinse away over the following 1–2 weeks.
Is it safe for my landscaping?
Professional crews pre-rinse landscaping before treatment and rinse thoroughly after. When properly applied and diluted, soft wash solutions are safe for established plants.
Can you clean metal roofs?
Yes. Metal roofs are cleaned with lower chemical concentration and slightly different technique. Metal roofs don’t have granule loss risk but can develop oxidation and biological growth that soft washing addresses effectively.