What’s Actually in
Roof Cleaning Chemicals in FL?
Most Florida roof cleaning mixes come down to three things: sodium hypochlorite, a surfactant, and water. Here is what each does, why it matters, and what to ask before anyone sprays your roof.
in Most Mixes
chlorite (Active)
Application
Florida is essentially a biological growth chamber for roof staining. Heat, humidity, afternoon storms, salt air near the coast, and shaded roof sections that never fully dry out create ideal conditions for:
Gloeocapsa Magma Algae
The organism behind the classic black streaks on asphalt shingles. Airborne, feeds on limestone filler in shingles, spreads across entire roofs. Does not rinse off with water — must be killed chemically.
Mold & Mildew
Forms in areas that stay damp — north-facing slopes, under tree canopy, around roof penetrations. Blotchy patches rather than streaks. Same chemical treatment as algae.
Lichen
Slow-growing, crusty, and deeply attached to roofing material. Harder to treat than algae and may require multiple applications or longer dwell time. More common on older tile roofs.
The critical point: organic growth does not rinse off. Water moves it around but does not kill it. Effective roof cleaning in Florida requires chemistry — specifically chemistry that kills the organism at the root rather than just displacing surface staining.
Sodium Hypochlorite (SH) — The Active Ingredient
The primary active ingredient in professional Florida roof soft washing. Same chemical family as household bleach but handled and diluted differently. SH is a strong oxidizer — it breaks down and kills algae, mildew, and mold organisms. The staining lightens because the pigment is part of the organism or what it leaves behind. The key variable is concentration: too weak and it does not work, too strong and it risks damage to surrounding materials. A contractor who says “it’s just bleach” or “it’s totally harmless” without specifics is not giving you useful information about their process.
Surfactant — The Soap That Makes It Work
Surfactants are what make soft wash solutions actually behave on a roof. Without them, the mix runs off steep slopes before it has time to dwell. Surfactants help the solution cling to the surface, penetrate porous material and get into the organism layer, and spread evenly to prevent striping and missed patches. Roof surfactants must be compatible with SH — not all soaps work with bleach-based solutions. A contractor using the right surfactant produces more consistent results with less chemical waste.
Water — The Dilution That Determines Safety
Water is not just a carrier — the dilution ratio determines the difference between a safe, effective application and one that damages landscaping, stains gutters, or oxidizes metal components. Final SH percentage on the roof varies by contractor, roof type, staining severity, temperature, and intended dwell time. There is no universal recipe. This is part of the skill, and why technique matters as much as the product itself.
Some mixes also include buffers or stabilizers that improve performance in Florida heat (roof surfaces behave differently at 9am vs 2pm), and adjustments for tile vs shingle vs metal applications. The chemistry is the foundation, but the technique — dwell time, application pattern, runoff management, and rinsing — is what separates good results from problem jobs.
The most common homeowner concern is what the chemicals do to everything around the roof. This is a legitimate question — and the answer is mostly about technique, not just the product.
✅ What Proper Process Looks Like
- Pre-wet all landscaping before application starts
- Keep plants wet throughout the job in Florida heat
- Manage downspout zones where runoff concentrates
- Rinse all surrounding surfaces after roof is complete
- Post-rinse landscaping a second time later same day
- Control overspray near screen enclosures and pool cages
🔴 Red Flags in the Process
- No plant protection discussion before starting
- Solution applied with no pre-wetting of landscaping
- No post-rinse after the roof is done
- Overspray reaching screen enclosures unchecked
- Runoff draining directly into flower beds
- Fast job with no attention to surrounding property
SH on metal can cause oxidation if mishandled — gutters, fasteners, screen enclosure frames, and painted surfaces are all things that require technique and rinse management. A professional crew accounts for these in how they apply the mix and where they direct rinse water, not just in what product they use.
Sodium hypochlorite is useful on a roof because it is reactive, and that same property makes mixing mistakes dangerous. The Washington State Department of Health puts it plainly: don’t mix bleach with ammonia, acids, or other cleaners. When bleach meets ammonia, toxic gases called chloramines form, and exposure can bring coughing, shortness of breath, watery eyes, chest pain and, in serious cases, fluid in the lungs. When chlorine bleach meets an acid, chlorine gas is given off; the department lists vinegar and toilet bowl cleaners among the acid-containing products people have at home.
Exterior cleaning crews carry acids too. Rust and mineral-stain removers are typically acid-based, so on a job site hypochlorite and acid products should never share a tank, hose, sprayer or bucket, and they belong on separate passes with a full rinse in between. The department’s other advice applies to any homeowner tempted to finish a corner with a store-bought product: read the product label before using it, and if someone develops symptoms after an exposure, contact a health care provider or call 911.
For asphalt shingles, the Asphalt Roofing Manufacturers Association names household bleach, which is sodium hypochlorite, mixed with water as the cleaning solution, with the strength set by the shingle manufacturer’s directions for the amount of staining. ARMA wants it applied gently, left on for at least 15 minutes but no more than 20, and rinsed with a gentle spray. It also cautions against using other chemicals or methods without the manufacturer’s approval, and against scrubbing, which can loosen the granules.
Concrete tile makers set a more conservative starting point. Eagle Roofing Products recommends plain water first, and where heavier buildup calls for a cleaner, it asks that the cleaner be used only in the most diluted solution possible and be safe for concrete, warning that some products can affect the pH of the tile or even etch the surface. Eagle also caps water pressure at 1,200 psi. On a Florida tile roof, that guidance is the reason mix strength on tile should be set separately from shingle, with a small test area done first.
Even the right mix applied the right way does not make a roof immune. ARMA describes the cleaning effect as temporary and says the discoloration can return, because the algae travel through the air and simply settle again. In Naples, after a proper soft wash, results can last 24 to 36 months, with shaded slopes and roofs under oak or pine canopy usually the first to show color again.
When a shingle roof is near replacement anyway, ARMA points to algae-resistant shingles, which are made to resist growth for longer periods, as worth considering. For an existing roof, the practical steps are the ones that cut the moisture the organisms need: trim limbs back from the roof, keep gutters and valleys clear of leaf litter, and book the next cleaning when the first faint streaks appear rather than when the whole slope has darkened.
We provide soft wash roof cleaning in Naples FL using properly formulated SH-based mixes with full landscaping protection — see all service areas.
About the Author
Owner Blane Perun started this company with a simple premise: Naples homeowners deserve a professional exterior cleaning option that doesn’t come with the inflated pricing of franchise operations and large corporate companies.
