If you own a home in Pinellas County, you have seen those dark black streaks running down roofs all over the area. You may have noticed them creeping across your own roof. Those streaks are not dirt, not mold (though mold can be present too), and not a sign that your shingles are failing. They are caused by a specific algae called Gloeocapsa magma, and in Florida's warm, humid climate, it thrives on virtually every asphalt shingle roof.
Roof cleaning is more than cosmetic. Left unchecked, biological growth can shorten your roof's lifespan, drive up energy costs, attract insurance scrutiny, and tank your home's curb appeal. This guide covers everything Pinellas County homeowners need to know about roof cleaning in 2026: what it costs, which methods work (and which damage your roof), how often to schedule it, and what your insurance company might have to say about it.
Roof Cleaning Cost Overview (2026)
Roof cleaning prices in Pinellas County depend on the cleaning method, your roof size and type, the severity of biological growth, and roof accessibility. Here is a general pricing breakdown:
| Cleaning Method | Cost Range | Best For | Roof Safe? |
|---|---|---|---|
| Soft Wash | $300 to $600 | Asphalt shingles, tile, metal | Yes |
| Pressure Wash | $200 to $500 | Concrete/clay tile only (with care) | NOT for shingles |
| Chemical Treatment | $400 to $800 | Heavy algae/lichen, preventive treatment | Yes (when properly diluted) |
The most common service booked in Pinellas County is soft wash roof cleaning, with the average homeowner paying $400 to $500 for a standard single-story home with an asphalt shingle roof. Multi-story homes, tile roofs, and heavily stained roofs fall toward the higher end of each range.
Soft Wash Roof Cleaning: $300 to $600
Soft washing is the industry-standard, manufacturer-recommended method for cleaning residential roofs. It uses low-pressure water (no more than a standard garden hose pressure, typically 60 to 100 PSI) combined with specialized cleaning solutions to kill algae, mold, mildew, and lichen on contact.
The cleaning solution is typically a sodium hypochlorite (bleach) blend at a concentration of 1% to 3%, combined with surfactants that help the solution cling to the roof surface. The solution is applied with a low-pressure sprayer, allowed to dwell for 15 to 30 minutes, and then either rinsed off gently or left to rinse naturally with the next rainfall.
How Soft Washing Works
The cleaning solution does the work, not water pressure. Sodium hypochlorite kills the biological organisms causing the staining. The surfactants break the bond between the organic material and the roof surface. Within minutes, the dark staining begins to lighten. Some areas may take a few rain cycles to fully clear as the dead algae washes away naturally.
A skilled soft wash technician can clean an entire roof in 2 to 4 hours depending on size and severity. The results are dramatic. Roofs that looked like they needed replacement often look nearly new after a proper soft wash treatment.
Soft Wash Cost Factors
- Roof size: The primary cost driver. Most contractors price by the square foot or by the "roofing square" (100 sq ft). A 2,000 sq ft roof (roughly 20 squares) costs less to clean than a 3,000 sq ft roof.
- Roof pitch: Steeper roofs require more safety equipment, slower work, and sometimes specialized rope access. A 6/12 pitch roof costs 15% to 25% more to clean than a standard 4/12 pitch.
- Severity of growth: A roof with light streaking is quicker and cheaper to clean than one with heavy algae, moss, or lichen buildup that requires multiple applications.
- Roof material: Tile roofs (common in Pinellas County) can cost more to clean because the textured surface requires more solution and more careful application to reach algae growing in the tile grooves.
- Accessibility: Homes with screen enclosures, solar panels, or limited ground access require extra time and care.
Soft Wash Cost by Roof Size
| Roof Size (sq ft) | Soft Wash Cost | Chemical Treatment Cost |
|---|---|---|
| 1,500 to 2,000 | $300 to $400 | $400 to $550 |
| 2,000 to 2,500 | $350 to $500 | $450 to $650 |
| 2,500 to 3,000 | $400 to $550 | $550 to $750 |
| 3,000+ | $500 to $600+ | $650 to $800+ |
Pressure Washing: Why It Is NOT Recommended for Most Roofs
Pressure washing uses high-pressure water (1,500 to 3,000+ PSI) to blast away surface contaminants. While it works well on driveways, sidewalks, and pool decks, pressure washing causes significant damage to most roofing materials.
Damage to Asphalt Shingles
The granule coating on asphalt shingles is the first line of defense against UV radiation. These tiny ceramic-coated particles are embedded in the asphalt surface and gradually shed naturally over the shingle's 20 to 30 year lifespan. Pressure washing strips years' worth of granules in a single pass, dramatically accelerating shingle aging and voiding the manufacturer warranty.
After pressure washing, you may notice granule buildup in your gutters and bare spots on the shingles where the underlying asphalt is exposed. Those bare spots will deteriorate rapidly in Florida's intense UV environment, potentially leading to leaks within a few years.
When Pressure Washing Might Be Appropriate
There are limited situations where pressure washing is acceptable on a roof:
- Concrete tile roofs: With careful technique and moderate pressure (under 1,500 PSI), concrete tile can tolerate pressure washing. However, even here, soft washing produces comparable results with less risk.
- Clay tile roofs: Some experienced contractors use moderate pressure on barrel tile, but the glaze on clay tile can be damaged by high pressure. Soft washing is safer.
- Metal roofs: Standing seam metal can handle moderate pressure, but soft washing is equally effective and carries less risk of denting the panels or forcing water into seams.
The bottom line: for virtually every residential roof type in Pinellas County, soft washing is safer, equally effective, and recommended by both roofing manufacturers and the Asphalt Roofing Manufacturers Association (ARMA). Do not let a contractor talk you into pressure washing your shingle roof.
Chemical Treatment: $400 to $800
Chemical roof treatments go beyond a standard soft wash by applying longer-lasting solutions designed to kill existing biological growth and prevent regrowth for an extended period. These treatments use higher concentrations of active ingredients, specialized algaecides, or copper-based solutions that provide residual protection.
A typical chemical treatment involves a two-step process: first, a cleaning application that kills and removes existing algae and staining (similar to a soft wash), followed by a preventive treatment that creates a barrier against regrowth. Some treatments use zinc or copper solutions that slowly release over months, continuously inhibiting algae colonization.
Chemical treatments cost $400 to $800 for a typical Pinellas County home, depending on roof size and the specific products used. The higher cost compared to soft washing reflects the added materials and the extended protection period. A quality chemical treatment can keep your roof clean for 3 to 5 years compared to 2 to 3 years for a standard soft wash.
Environmental Considerations
Roof cleaning chemicals must be handled responsibly. The runoff from a roof cleaning treatment contains sodium hypochlorite and potentially other biocides that can harm landscaping, kill beneficial soil organisms, and pollute stormwater systems. Reputable contractors in Pinellas County take precautions including:
- Pre-wetting plants and landscaping around the home before application
- Covering sensitive plantings with plastic sheeting during treatment
- Rinsing landscaping thoroughly after the roof cleaning is complete
- Using neutralizing agents on the ground around the home
- Following Pinellas County stormwater regulations regarding chemical runoff
Ask your roof cleaning contractor what environmental protections they take. If they dismiss the question or do not have a clear protocol, choose someone else.
Understanding Black Algae: Gloeocapsa Magma
The dark black streaks running down roofs throughout Pinellas County are caused by Gloeocapsa magma, a species of cyanobacteria (commonly called blue-green algae). Understanding this organism helps you make better decisions about cleaning and prevention.
Why It Grows in Florida
Gloeocapsa magma feeds on the calcium carbonate (limestone) filler used in asphalt shingles. It needs warmth, moisture, and its food source. Florida provides all three in abundance. The organism arrives on your roof as airborne spores carried by wind. Once it lands on a shingle surface, it begins to colonize, forming colonies that appear as small dark spots. Over time, these spots merge into the characteristic dark streaks that run down the roof following the path of water flow.
The dark color is not the algae itself but rather a protective outer layer (melanin sheath) that the organism produces to shield itself from UV radiation. Ironically, the darker the streaks, the more UV protection the algae has, which allows it to spread further.
Impact on Your Roof
Gloeocapsa magma does not directly eat through your shingles, but it does cause real damage over time:
- Heat absorption: The dark staining absorbs more solar radiation than the original shingle color, raising roof surface temperatures. This accelerates asphalt aging and increases cooling costs. Studies have shown that a heavily stained dark roof can be 10 to 15 degrees hotter than a clean roof of the same color.
- Moisture retention: Algae colonies hold moisture against the shingle surface, keeping it damp longer after rain. This prolonged moisture contact accelerates granule loss and can promote the growth of more destructive organisms like moss and lichen.
- Aesthetic degradation: The visual impact is significant. A stained roof makes an otherwise well-maintained home look neglected, which directly affects property value and neighborhood perception.
North-Facing Slopes Get Hit Hardest
In Pinellas County, north-facing roof slopes almost always show more algae staining than south-facing slopes. The north side receives less direct sunlight, stays damp longer after rain, and provides the shadier, moister conditions that Gloeocapsa magma prefers. If you are noticing black streaks only on certain parts of your roof, check which direction those slopes face. North and east-facing slopes are typically the first to show staining.
Moss and Lichen Removal
While Gloeocapsa magma (algae) is the most common biological growth on Pinellas County roofs, moss and lichen also appear and require different treatment considerations.
Moss
Moss is a plant that grows in thick, green mats. It is less common in Pinellas County than in cooler, wetter climates, but it does appear on shaded roof sections, especially under tree canopy. Moss is more damaging than algae because it sends root-like structures (rhizoids) into the shingle surface, lifting the edges of shingles and creating pathways for water to penetrate beneath them.
Removing moss requires careful soft washing with a moss-specific treatment. Simply scraping or brushing off moss without killing it first damages the shingles. After treatment, dead moss should be gently removed (not power-washed) to avoid dislodging granules. Moss removal typically adds $50 to $150 to a standard soft wash cleaning.
Lichen
Lichen is a composite organism (a fungus living symbiotically with algae) that forms small, circular, crusty patches on roof surfaces. Lichen is extremely tenacious and more difficult to remove than either algae or moss. It adheres firmly to the shingle surface and can leave permanent marks even after removal.
Lichen removal usually requires stronger chemical treatment and sometimes multiple applications. Budget $100 to $200 extra for significant lichen treatment. In severe cases, the shingles beneath heavy lichen growth may be damaged enough to warrant replacement rather than just cleaning.
Roof Cleaning Frequency in Florida
How often you need to clean your roof depends on several factors specific to your property. Here are general guidelines for Pinellas County homeowners:
Every 1 to 2 Years
- Homes with heavy tree canopy (especially oak trees)
- Homes near bodies of water (higher humidity microclimate)
- Roofs with predominantly north-facing slopes
- Properties where algae reappears quickly after cleaning
Every 2 to 3 Years
- Most Pinellas County homes with moderate shade
- Homes with standard asphalt shingle roofs
- Properties where a previous soft wash lasted well
Every 3 to 5 Years
- Homes with minimal shade and good sun exposure
- Homes that received a chemical preventive treatment with their last cleaning
- Metal or tile roofs that are less susceptible to algae colonization
- Homes with algae-resistant (AR) shingles
Algae-Resistant Shingles
If you are considering a roof replacement, ask about algae-resistant (AR) shingles. These shingles have copper granules mixed into the surface that slowly leach copper ions when wet, inhibiting algae growth. AR shingles cost roughly 10% to 15% more than standard shingles but can extend the time between cleanings significantly. They are especially valuable in Pinellas County's algae-friendly climate.
Insurance Requirements and Roof Cleaning
This is a topic that catches many Florida homeowners off guard. Insurance companies in Florida have become increasingly aggressive about roof condition as a factor in underwriting and renewal decisions. Algae staining, moss growth, and general roof appearance are now legitimate reasons for policy action in many cases.
What Insurance Companies Look For
Many Florida home insurance carriers conduct periodic drive-by or aerial inspections of insured properties. They are looking for:
- Heavy algae staining: Dark staining covering a significant portion of the roof
- Moss or vegetation growth: Visible moss, lichen, or plant growth on the roof surface
- Debris accumulation: Leaves, branches, and debris sitting on the roof
- Visible damage: Missing shingles, lifted edges, or sagging sections
If their inspection reveals concerns, the insurer may send you a letter requiring corrective action within 30 to 60 days. Failure to comply can result in policy non-renewal at the next renewal date or, in some cases, cancellation.
How to Protect Yourself
- Clean proactively: Do not wait for an insurance letter. Regular cleaning every 2 to 3 years keeps your roof looking maintained and avoids triggering insurer concern.
- Keep records: Save receipts and before/after photos from every roof cleaning. If an insurer questions your roof condition, having documentation of regular maintenance is your strongest defense.
- Get a roofer's assessment: If you receive an insurance letter about your roof, have a licensed roofer inspect it and provide a written assessment of its condition. A clean bill of health from a roofer carries weight with insurance adjusters.
- Know your rights: Florida law provides protections against unjust policy cancellations. If your insurer cancels based solely on cosmetic algae staining on an otherwise sound roof, consult with an insurance attorney.
Warranty Implications of Roof Cleaning
Your choice of cleaning method directly affects your shingle warranty. Here is what you need to know:
What Voids the Warranty
- Pressure washing: Most shingle manufacturers explicitly state that pressure washing voids the warranty. GAF, CertainTeed, Owens Corning, and IKO all prohibit high-pressure cleaning.
- Walking on the roof in extreme heat: Florida roofs can be soft and pliable when surface temperatures exceed 130 degrees. Foot traffic during the hottest part of the day can permanently damage heated shingles.
- Unapproved chemical products: Using cleaning solutions not approved by the manufacturer (such as highly concentrated acids) can damage shingle composition and void coverage.
What Preserves the Warranty
- Soft washing at approved pressures: Low-pressure application (under 300 PSI) is accepted by virtually all major shingle manufacturers.
- ARMA-recommended methods: The Asphalt Roofing Manufacturers Association publishes guidelines for safe roof cleaning. Following these guidelines protects your warranty.
- Professional application: Having the work done by a licensed, insured professional who follows manufacturer guidelines provides documentation that you maintained the roof properly.
DIY Roof Cleaning: Is It Worth the Risk?
DIY roof cleaning products are available at home improvement stores, and some homeowners consider cleaning their own roofs to save $300 to $600. While it is technically possible, there are significant reasons to think twice:
- Safety: Falls from roofs and ladders are a leading cause of home injury deaths. Florida's steep roof pitches, tile surfaces, and frequent afternoon rain make the risk even higher.
- Chemical handling: Roof cleaning solutions contain sodium hypochlorite at concentrations that can cause chemical burns, damage eyes, and harm landscaping if mishandled.
- Effectiveness: Professional-grade soft wash systems deliver the solution at precise dilutions and pressures. Garden hose attachments and pump sprayers often produce inconsistent results.
- Warranty risk: If you damage your roof during cleaning, the expense of a professional would have been far cheaper than the repair.
- Liability: If you fall off your roof or damage a neighbor's property with chemical runoff, you are personally liable. A licensed contractor carries insurance for exactly these situations.
For the vast majority of Pinellas County homeowners, the $300 to $600 cost of professional soft washing is well worth the safety, effectiveness, and peace of mind it provides.
Roof Cleaning Cost by Roof Type
Different roofing materials have different cleaning requirements and costs. Here is how common Pinellas County roof types compare:
| Roof Type | Cleaning Method | Cost Range | Notes |
|---|---|---|---|
| Asphalt Shingle | Soft wash only | $300 to $550 | Most common in Pinellas County |
| Concrete Tile | Soft wash preferred | $400 to $700 | Textured surface needs more solution |
| Clay (Barrel) Tile | Soft wash only | $450 to $750 | Fragile; walk carefully |
| Metal (Standing Seam) | Soft wash or gentle rinse | $250 to $450 | Less algae growth; easier to clean |
| Flat (Modified Bitumen) | Chemical treatment | $300 to $500 | Focus on standing water areas |
Choosing a Roof Cleaning Contractor in Pinellas County
The roof cleaning industry has a low barrier to entry, which means quality varies dramatically. Here is how to find a reliable contractor:
- Soft wash only: Any contractor who suggests pressure washing your asphalt shingle roof is immediately disqualified. This is the most basic test of competence.
- Licensed and insured: Verify their Florida business license and ask for proof of general liability insurance (minimum $1 million) and workers compensation coverage.
- Environmental protocol: Ask how they protect your landscaping, where runoff goes, and what products they use. A reputable company has clear answers.
- Written estimate: The quote should specify the cleaning method, products used, what is included (gutters, walkways, etc.), and any warranty on the treatment.
- Before and after photos: Ask to see examples of previous work on homes similar to yours in the Pinellas County area.
- Treatment warranty: Many soft wash companies offer a 1 to 3 year warranty against algae regrowth. This is a sign of confidence in their process.
Bundling Roof Cleaning with Other Services
Most roof cleaning companies also offer exterior cleaning services that can be bundled for savings:
- Roof + gutter cleaning: Save 10% to 15% by combining both services. Cleaning gutters after a roof treatment makes sense since debris and treatment runoff end up in the gutters.
- Roof + driveway/sidewalk: Many companies offer a whole-property package. Saves 15% to 20% over booking separately.
- Roof + house wash (siding/stucco): A complete exterior cleaning refreshes the entire property. Bundled pricing typically saves 20% to 25%.
- Roof + screen enclosure cleaning: Very popular in Pinellas County where screen-enclosed patios and pool cages are standard. Saves 10% to 15%.
Frequently Asked Questions
How much does roof cleaning cost in Florida?
Roof cleaning in Florida costs between $300 and $800 depending on the method and roof size. Soft washing costs $300 to $600 for most homes, while chemical treatments run $400 to $800. The average Pinellas County homeowner pays around $400 to $500 for a professional soft wash roof cleaning.
What causes the black streaks on Florida roofs?
Black streaks on Florida roofs are caused by Gloeocapsa magma, a type of blue-green algae (cyanobacteria) that feeds on the limestone filler in asphalt shingles. Florida's warm, humid climate is ideal for this algae. The dark streaks are actually the algae's protective outer coating that shields it from UV rays.
Is pressure washing safe for my roof?
Pressure washing is NOT recommended for most residential roofs. High-pressure water strips granules from asphalt shingles, damages tile glaze, and can force water under roofing materials. Soft washing (low-pressure application of cleaning solutions) is the industry-recommended method that effectively removes algae and stains without damaging your roof.
How often should I clean my roof in Florida?
Most Florida homeowners should clean their roof every 2 to 3 years to prevent algae and moss buildup. Homes under heavy tree canopy or on the north side of a building may need cleaning annually. Some insurance companies in Florida require roof cleaning every 3 years as a condition of maintaining your homeowners policy.
Will my insurance cancel if I do not clean my roof?
Some Florida insurance companies do cancel or non-renew policies based on roof condition, including algae and moss growth. Insurers may send inspectors to photograph your roof and require cleaning within 30 to 60 days. This is increasingly common in the Pinellas County area where algae growth is prevalent year-round.
Does roof cleaning void my shingle warranty?
Pressure washing can void your shingle warranty because it damages the protective granule layer. However, soft washing (low-pressure cleaning with approved solutions) is generally accepted by shingle manufacturers and will not void your warranty. Always check your specific warranty terms and use a contractor familiar with manufacturer guidelines.
The Bottom Line on Roof Cleaning in Pinellas County
Roof cleaning is a necessary part of home maintenance in Florida, not just a cosmetic choice. The combination of warm temperatures, high humidity, and abundant rainfall makes Pinellas County one of the most algae-prone areas in the country. Regular soft wash cleaning every 2 to 3 years keeps your roof looking good, extends its lifespan, maintains your insurance standing, and protects your property value.
Budget $300 to $600 for a standard soft wash or $400 to $800 for a chemical treatment with preventive protection. Choose a contractor who uses soft wash methods exclusively, carries proper insurance, and protects your landscaping from chemical runoff. Avoid anyone who suggests pressure washing your shingle roof, no matter how confident they sound.
A clean roof is a healthy roof. In Pinellas County's demanding climate, investing a few hundred dollars every couple of years is one of the simplest ways to protect your home's most important line of defense.