Roof Cleaning · Jacksonville, FL
Roof Cleaning in Jacksonville, FL
Those dark streaks running down your shingles are algae, not dirt or old age. A gentle soft wash removes them without shortening the life of your roof.
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- Duval · Clay · St. Johns
Quick answer
Roof cleaning in Jacksonville should never use high pressure on shingles. The safe method is a soft wash: a cleaning mix approved by the shingle maker, applied at low pressure, left to dwell, then rinsed gently. It kills the algae causing the black streaks and leaves the protective granules in place.
What Causes Black Streaks on Roofs
The Asphalt Roofing Manufacturers Association explains that the dark streaks are mostly a blue green algae called Gloeocapsa magma. Its spores ride the wind, so once one roof in a neighborhood has it, nearby roofs soon do too. It grows best in warm, humid places, which describes Northeast Florida most of the year.
The streaks show first on north facing slopes and under trees, where the roof stays damp after dew and rain. Light gray and white shingles show it most. Over time the algae can be joined by moss and lichen, which hold even more water against the roof.
Why You Should Never Pressure Wash a Shingle Roof
Asphalt shingles are covered with small granules that shield the asphalt from the Florida sun. The roofing industry group warns against using power washers, brushes or brooms on shingles because they knock those granules loose. Once the granules are gone, the shingle ages faster and may not be covered by the maker's warranty.
High pressure also lifts shingle edges, breaks the seal strips and can push water under the roof. On tile roofs it can crack tiles and wash out the coating. If anyone offers to pressure wash your roof, thank them and keep looking.
What a Proper Roof Soft Wash Looks Like
- Inspect from the ground and the roof edge
Your pro looks for lifted or missing shingles, cracked tiles, soft decking and loose flashing. If the roof needs repair, cleaning should wait.
- Protect the yard
Plants, grass under the drip line and pool areas get soaked with water first. Downspouts may be directed away from beds.
- Apply the cleaning mix gently
The mix goes on at low pressure, from a ladder, a roof harness or the ground, depending on the pitch. Your pro avoids walking on the roof when possible.
- Let it dwell
The mix needs time to kill the algae. Many streaks fade during this step. Heavy growth may need a second coat.
- Rinse and clean up
A gentle rinse carries away the dead growth. Gutters and plants get flushed with plain water. Some faint shadows may keep fading for a few weeks as rain washes them off.
Tile and Metal Roofs
Many homes in Ponte Vedra Beach, Nocatee and the newer parts of the Southside have concrete or clay tile. Tile can take a bit more water, but the same rule applies: low pressure and a cleaning mix. Older tile may have a painted coating that high pressure strips right off.
Metal roofs on homes and barns in western Duval and Clay County do well with a soft wash too. Your pro will rinse carefully around fasteners and seams.
Safety on the Roof
Roof work is risky. A two story roof in Mandarin or a steep tile roof near TPC Sawgrass is no place for guessing. Ask your pro how they stay safe on a roof, whether they carry liability insurance, and whether they will walk the roof at all. A pro who can clean from a ladder or the ground puts less wear on your roof.
How to Keep Streaks From Coming Back
- Trim trees: more sun and air means the roof dries faster.
- Keep gutters clear: clogged gutters hold water at the roof edge. See gutter cleaning.
- Consider zinc or copper strips: when rain hits these metals near the ridge, it washes down a small amount that slows algae growth.
- Choose algae resistant shingles when you reroof: many brands make shingles with copper granules built in.
Most Jacksonville roofs need a cleaning every few years, depending on shade and roof color.
Roof Cleaning Questions
Is roof cleaning safe for my shingles?
A low pressure soft wash with a mix approved by the shingle maker is the method the roofing industry suggests. Pressure washing is not.
Will the cleaning mix kill my plants?
A careful pro soaks plants before and after and rinses gutters and beds. Ask how they protect plants under the roof line.
How long does a clean roof stay clean?
Often a few years. Shaded roofs and light colored shingles may need it sooner.
Can I clean my roof myself?
It is not a job most homeowners should do. Ladders, wet roofs and cleaning mix make for a risky combination.
Same day quote requests welcome
Get a Roof Cleaning Quote
Send your address and a photo of the streaks if you can. A local pro will look at the roof and send a free written quote. Request your quote or see how the process works.
More services
Other exterior cleaning services in Jacksonville
House Washing
Soft wash for siding, stucco and brick that kills mildew at the root.
Driveway & Concrete
Surface cleaning for driveways, walks, pool decks and patios.
Paver Cleaning & Sealing
Deep clean, fresh joint sand and a sealer that fights weeds and fading.
Deck & Fence Cleaning
Gentle washing that brings gray wood back without raising splinters.
Gutter Cleaning
Pine needles and oak leaves cleared, downspouts flushed before storm season.
Window Cleaning
Salt film, pollen and hard water spots cleared from glass and screens.
Commercial Pressure Washing
Storefronts, sidewalks, dumpster pads and HOA common areas.