Black Streaks on Your Roof in Central Florida? Here’s the Safe, Florida-Proof Fix
Seeing black streaks on your shingles? In Central Florida’s heat and humidity, that’s almost always algae—typically Gloeocapsa magma. The good news: you don’t need harsh pressure washing to get your curb appeal back. A careful, low-pressure soft wash following manufacturer guidance can lift stains without grinding away shingle granules. Below, we’ll show you what’s causing the streaks, how soft washing works, and smart ways to keep algae from coming right back.
Black Streaks on Your Roof: What It Is (and Isn’t)
Those dark, trailing marks are colonies of algae. They thrive in warm, humid environments, hold moisture on shingles, and can make an otherwise healthy roof look years older. While the stains are mostly cosmetic, the moisture retention they create isn’t great for shingle longevity—so cleaning them the right way matters.
Why Central Florida Roofs Get It More Often
- Humidity + dew: Our region sees frequent high humidity and overnight dew—prime conditions for algae.
- Sun angle & orientation: North and shaded slopes dry more slowly, so streaks linger and spread.
- Airborne spores: When one neighborhood has stains, nearby homes often follow.
Soft Wash: Remove Black Streaks on Your Roof (Step-by-Step)
- Protect people, pets, and plants. Pre-wet landscaping, cover delicate plants, rinse again after.
- Use low pressure—skip the power washer. High pressure can dislodge granules and shorten roof life.
- Apply an approved cleaner. Most shingle makers support a sodium-hypochlorite (household bleach) + water mix; always follow the product label and manufacturer instructions.
- Work bottom-to-top, then top-to-bottom. Allow dwell time (often up to ~20 minutes) and rinse thoroughly. Multiple light passes beat one aggressive application.
- Choose the right time of day. A cooler, cloudy morning improves dwell time and protects landscaping.
- Mind metals and runoff. Rinse gutters and exposed metals; keep runoff away from sensitive plants.
- Document and inspect. Photos before/after help track results; note any lifted shingles or cracked flashing.
Prevention: Keep Algae Away Longer
- Algae-Resistant (AR) shingles: Copper-containing granules slowly release ions that discourage growth.
- Strategic trimming: Prune overhanging branches so the roof dries faster after summer downpours.
- Ridge-line metal strips: Copper or zinc near the ridge can help (effectiveness varies by placement and rainfall).
- Routine checkups: A quick annual roof check can catch small issues before they turn into repairs.
When to Repair vs. Replace
If cleaning reveals granule loss, curling, blistering, or soft decking, a targeted repair is usually the next step. If your roof is 15–20+ years old or shows widespread aging, algae may be a symptom of broader wear. In that case, a roof replacement may deliver better long-term value than repeated cleanings.
Free Inspection + Soft-Wash Quote: Get a clear plan—clean, repair, or replace—based on your roof’s condition. Book now or call (407) 461-0234.
Book a Free Inspection & Soft-Wash Quote
We serve Central Florida—including Orange, Seminole, Osceola, and Lake counties. We’ll confirm whether soft washing is appropriate for your shingle type, protect your landscaping, and provide prevention options so streaks don’t return quickly.
Next step: Contact us for your free roof inspection and soft-wash quote, or call (407) 461-0234.
Trusted Sources
- Asphalt Roofing Manufacturers Association (ARMA) — guidance on roof cleaning and algae.
- GAF Technical Resources — bulletins on cleaning methods and mixtures.
- Florida Climate Center — humidity and precipitation data for Florida.
FAQs
Are black streaks mold?
They’re usually algae, not mold. The stains hold moisture and spread over time—soft washing is the safest removal method for most shingle roofs.
Is pressure washing safe for shingles?
High pressure can remove protective granules and shorten roof life. Soft washing uses the right cleaner at low pressure to protect the shingle surface.
Will the streaks come back?
Eventually, algae can return in Florida’s climate. AR shingles, copper/zinc at the ridge, and better roof drying help extend the clean look.
How much does roof soft washing cost?
Pricing depends on roof size, pitch, access, and staining. Book a free inspection and soft-wash quote for an exact price.
