Residential Service
Roof Soft Washing in St. Augustine, FL
Those black streaks running down your roof are live algae eating into your shingles. Pressure washing damages what it is supposed to clean. Soft washing eliminates the bacteria safely using the method shingle manufacturers actually recommend.
Free Estimate
Get a Roof Soft Wash Quote
Tell us what needs cleaning and where it is. You get a written quote for your property within one business day, not a price range that moves once the crew arrives.
- A written quote within one business day
- No surprise add-ons once the crew arrives
- Residential and commercial property across St. Johns County
- Surface-specific methods, so nothing gets damaged
Tell Us About Your Property
Why St. Augustine Roofs Go Dark
Florida's Coast Creates the Worst Conditions for Roof Algae
St. Augustine sits at the intersection of two conditions that algae love: coastal humidity and warm temperatures that persist year-round. Gloeocapsa magma (the cyanobacteria responsible for those dark streaks) thrives in exactly this environment. The organism spreads from roof to roof on the wind, which is why you will often see entire neighborhoods with streaked roofs rather than isolated houses.
The algae feeds on the limestone filler in asphalt shingles. As it grows, it damages the granule surface that reflects UV light and protects the asphalt beneath. Homeowners in the Historic District, on Anastasia Island, and along Vilano Beach report accelerated streaking because salt air and consistent moisture create near-ideal growing conditions for algae and lichen.
The visual problem is also a structural one. Untreated algae that has colonized a roof for three or more years measurably shortens shingle life and can contribute to early replacement costs. The treatment cost is a fraction of a roof replacement, and soft washing done correctly keeps the problem from returning for years.
The Right Method
What Roof Soft Washing Actually Does
Soft washing is not diluted pressure washing. It is a distinct method that uses very low water pressure (typically under 100 PSI at the surface) combined with a professional algaecide solution that kills the bacteria, moss, and lichen on contact rather than just blasting the visible staining away. The solution dwells on the surface, breaks down the biological growth at its root, and is then rinsed at pressures that no shingle manufacturer considers damaging.
The Asphalt Roofing Manufacturers Association (ARMA) explicitly recommends this low-pressure chemical cleaning approach and warns against high-pressure washing. Most major shingle brands (including GAF and Owens Corning) list high-pressure washing as a warranty-voiding activity. Soft washing protects the warranty while eliminating the problem more thoroughly than pressure ever could.
- Pre-treatment of gutters and landscaping below the roofline
- Full roof application of professional-grade algaecide solution
- Targeted dwell time based on severity of growth
- Low-pressure rinse that does not disturb granules
- Post-treatment inspection for lichen or moss requiring additional passes
- Gutter and downspout rinse on completion
Roof Types We Clean
Asphalt, Tile, Metal, and More
St. Augustine's housing stock includes a mix of asphalt shingle homes in newer subdivisions, clay and concrete tile roofing throughout established neighborhoods, metal standing-seam roofs on coastal properties, and painted flat or low-slope roofing on commercial and historic structures. Each surface type requires a different chemistry concentration and pressure level.
Asphalt shingles are the most common and the most algae-prone. Clay and concrete tile roofing can develop lichen and moss in addition to algae, and the grout lines between tiles create sheltered microenvironments that are particularly susceptible. Metal roofing develops algae in surface oxidation and at seams. We adjust our method for each surface type rather than applying a single formula across all of them.
Honest Fit Check
Is Roof Soft Washing the Right Call for Your Roof?
Roofs are the one surface where the wrong answer is expensive, so here is where this service does and does not apply.
A good fit if
- Dark streaks are running down your asphalt shingles
- Lichen or moss has taken hold on tile or in the grout lines
- Your roof is still under a manufacturer warranty you would rather not void
- You are near the water, where algae returns faster than inland
Not the right fit if
- The roof is already failing, with missing shingles or an active leak, because that is a roofer's job first
- You want the roof cleaned at high pressure, which strips granules and we will not do
- You need solar panels cleaned, which we do not service
- There is no safe ladder access to the roofline
Roof soft washing is quoted on roof size, pitch, material, and how far the growth has spread. Starting prices are on the pricing page.
The Process
How a Roof Soft Wash Runs
Roof work has more to protect than any other surface we clean, so the sequence matters more than the speed.
Send Us Your Roof Details
Roof material, roughly how old it is, the pitch, and how far the streaking has spread. A photo taken from the driveway tells us most of what we need.
Everything Below Your Roofline Gets Covered
Your landscaping, gutters, and any surface the runoff will reach get pre-wet and shielded before a drop of solution goes onto the roof. Plants are damaged by concentrated runoff, not by the wash itself.
Apply, Dwell, Then Low-Pressure Rinse
The algaecide goes on at low pressure and dwells long enough to kill Gloeocapsa magma at the root. Your rinse then runs at a pressure no shingle manufacturer objects to.
Second Pass on Lichen and Moss
Lichen roots into the granule surface and rarely clears in one application. Your full roof plane gets inspected and anything still holding on gets a second treatment before the equipment goes away.
FAQ
Common Questions from St. Augustine homeowners asking about roof soft washing
The dark streaks are caused by Gloeocapsa magma, a cyanobacteria that thrives in Florida's humid coastal climate. The algae feeds on the limestone filler in asphalt shingles, and left untreated it accelerates granule loss and shortens roof life significantly. St. Augustine's proximity to the ocean makes conditions especially favorable for rapid algae growth.
High-pressure water blasts away the protective granules embedded in asphalt shingles, voiding most manufacturer warranties and shortening the roof's lifespan. Soft washing uses low pressure combined with professional-grade algaecide to kill the bacteria at the root. The result lasts longer than pressure washing and does no surface damage.
Most standard residential roofs in St. Augustine take one to three hours depending on pitch, square footage, and the severity of algae or lichen growth. We assess and give you a realistic timeframe when we quote the job.
Soft washing using the ARMA-recommended sodium hypochlorite and surfactant method is explicitly approved by major shingle manufacturers. High-pressure washing, by contrast, is specifically listed as a warranty-voiding activity in most manufacturer documentation. We use the low-pressure method precisely because it protects the warranty.
Most St. Augustine roofs benefit from a soft wash every two to three years. Properties on Anastasia Island, Vilano Beach, or near tidal waterways tend to accumulate algae faster due to salt air and moisture, and may need annual treatment to stay ahead of buildup.
Yes. Tile roofs get the same low-pressure soft washing approach as asphalt shingles, since high pressure can crack tile or dislodge the granule coating on concrete tile. The algaecide treatment addresses the same biological growth regardless of roofing material.
Related Services
Other Exterior Cleaning Services in St. Augustine
Roof algae rarely travels alone. The same organisms that streak your roof often colonize gutters, facia boards, and the home exterior below the roofline. Combining services in one visit saves time and typically reduces the total cost.
Ready to get started?
Your Property Deserves a Clean Start
Send your property details and you will have a written, no-obligation estimate within one business day. Scheduling fits around your calendar, and the quote you approve is the price you pay.