If you've noticed black streaks running down your roof, you're not alone. It's one of the most common calls we get from Daytona Beach homeowners — and one of the most misunderstood cleaning jobs in the industry.

Here's the truth: you should never power wash a roof with high pressure. And yet, plenty of companies do exactly that. Understanding why it's wrong — and what the correct method is — could save you thousands of dollars in premature roof replacement.

What Are Those Black Streaks on Your Roof?

The black streaks you see on asphalt shingle roofs are almost always caused by Gloeocapsa magma — a type of cyanobacteria (commonly called algae) that feeds on the limestone filler used in asphalt shingles.

Florida's warm, humid climate is ideal for this organism. Once it establishes itself on a roof, it spreads rapidly, creating the characteristic dark streaking pattern that makes roofs look decades older than they are.

Left untreated, Gloeocapsa magma:

• Continues to spread across the entire roof surface
• Degrades the limestone filler in shingles, reducing their protective granule layer
• Shortens the lifespan of your roof by years
• Can eventually lead to premature shingle failure

The good news: it's completely treatable with the right method.

Why High-Pressure Washing Damages Roofs

High-pressure washing — the kind used on driveways and concrete — operates at 2,500–4,000 PSI. That pressure is appropriate for hard, durable surfaces like concrete. It is absolutely not appropriate for asphalt shingles.

Here's what high-pressure washing does to a shingle roof:

Strips granules: Asphalt shingles are coated with mineral granules that protect the underlying asphalt from UV degradation. High-pressure washing blasts these granules off the shingles, dramatically accelerating UV damage and shortening roof life.

Voids manufacturer warranties: Most shingle manufacturers explicitly state that high-pressure washing voids the product warranty. If you have a 30-year shingle and someone power washes it with high pressure, you may have just voided your warranty coverage.

Damages flashing and sealants: High pressure can dislodge flashing, break sealant bonds around penetrations, and force water under shingles — creating leak pathways that weren't there before.

Doesn't kill the algae: Even if high pressure removes the visible staining, it doesn't kill the algae at the root. The streaks return within months because the organism is still alive in the shingle surface.

The Correct Method: Soft Washing

The Asphalt Roofing Manufacturers Association (ARMA) recommends a specific method for roof cleaning: low-pressure soft washing with a sodium hypochlorite-based cleaning solution.

Here's how it works:

1. Application: A professional-grade cleaning solution is applied to the roof surface at low pressure (under 500 PSI). The solution contains sodium hypochlorite (similar to bleach, but formulated for roof cleaning) and surfactants that help it penetrate and cling to the surface.

2. Dwell time: The solution is allowed to dwell on the surface for 15–30 minutes. During this time, it kills the algae, mold, and mildew at the cellular level.

3. Rinse: The roof is rinsed with low-pressure water, removing the dead organic matter and cleaning solution.

The result: a clean roof with no granule loss, no warranty voiding, and algae that's been killed at the root — not just blasted off the surface. Soft-washed roofs stay clean significantly longer than high-pressure washed roofs because the organism is actually dead, not just temporarily removed.

How Long Does Roof Soft Washing Last?

A properly soft-washed roof typically stays clean for 3–5 years in Florida's climate. Some roofs stay clean longer; roofs surrounded by trees or in heavily shaded areas may need retreatment sooner.

We offer a 2-year warranty on our roof soft washing: if the algae returns within 2 years of treatment, we'll retreat the roof at no charge.

What About Tile Roofs?

Tile roofs — common in Daytona Beach's newer developments — require a slightly different approach. Concrete and clay tiles are more durable than asphalt shingles and can tolerate somewhat higher pressure, but soft washing is still the preferred method for removing algae and mold without damaging the tile surface or the underlayment beneath.

High-pressure washing on tile roofs can crack tiles, dislodge them from their mortar beds, and force water under the tile layer — all expensive problems to fix.

We're a Licensed Roofing Contractor

Most pressure washing companies are not roofing contractors. They may not understand the difference between shingle types, how to identify damaged areas that need repair before cleaning, or what pressure levels are safe for different roof materials.

Daytona Beach Pressure Washing holds Roofing Contractor License #CCC1336785. Every roof cleaning job includes a visual inspection of the roof surface — we identify damaged shingles, failing flashing, and other issues that need attention before or after cleaning.

Roof Soft Washing Pricing in Daytona Beach

• Standard residential roof (1,500–2,000 sq ft): $300–$450
• Larger residential roof (2,000–3,000 sq ft): $400–$600
• Tile roof: $350–$550 depending on size and condition
• 2-year warranty included on all roof soft washing jobs

Schedule Your Daytona Beach Roof Cleaning

Call (386) 564-6700 or request a free quote online. We serve Daytona Beach and all of Volusia and Flagler counties, typically scheduling within a few days of your request.