Why South Florida roofs turn dark and streaky
The black streaks on roofs around Broward, Miami-Dade and Palm Beach are almost never dirt. They are a colony of algae called Gloeocapsa magma, which feeds on the limestone filler used in asphalt shingles and on moisture that never really leaves the air here. The organism starts on the shaded, north-facing side of a roof, spreads with each rainy season, and holds water against the surface as it grows.
Once the streaks are visible, the growth has been building for a year or more. Cleaning the surface without killing the organism only removes the colour for a few months, which is why a roof can look clean after a rain and streaked again by the following summer.
Soft washing versus pressure washing
Soft washing means cleaning at low pressure, usually well under what a garden hose delivers at the nozzle, using a diluted cleaning solution to break down the algae, mold and mildew. The solution does the work and the rinse carries it away. Nothing is forced into the tile, the underlayment or the attic.
Pressure washing uses high pressure to blast material off a surface. It is the right method for concrete driveways, paver patios and pool decks, and the wrong method for a roof. On tile it erodes the glaze and the surface, on shingles it strips granules, and on either it can push water past the roof covering. Many roof manufacturers and warranties exclude damage caused by pressure cleaning, which is the practical reason PressureLess never puts a pressure tip on a roof.
How often should a South Florida roof be cleaned?
Most homes in this climate need a roof cleaning every two to three years. Roofs under heavy tree cover, roofs that face north, and roofs with shallow pitch or poor drainage tend to need it closer to every two years. A roof that was cleaned properly and stayed clear for a year is usually a roof with good sun exposure and airflow.
Waiting longer does not usually save money. Heavy growth takes more solution and more time, and in the meantime the organism is holding moisture against the roof surface. If you are unsure, a free on-site estimate answers it quickly.
What a PressureLess roof cleaning includes
We start by covering landscaping, plants and any sensitive fixtures, and by wetting down surrounding greenery. The cleaning solution is applied at low pressure, given time to work on the growth, and then rinsed with clean water. Gutters are checked while we are on the roof, and the ground and exterior walls are rinsed when we finish.
The last step is a walkthrough with you, so anything that needs another pass is handled before we leave. Roof cleanings carry a 2-year warranty: if algae returns on the cleaned roof before that period ends, we come back at no extra cost.
What roof cleaning costs here
Roof cleaning quotes start at $80. The final price depends on roof size, roof pitch, roof material and how much buildup there is, so a single-family tile roof in Weston and a two-story shingle roof in Fort Lauderdale will not land on the same number. Estimates are free and given after we have looked at the property.
Driveways, patios, pool decks and gutters are quoted the same way, alone or bundled with the roof. If you want a ballpark before booking, call (669) 333-WASH and describe the property.
How to choose a roof cleaning company
Ask three things: whether the company is licensed and insured, whether the cleaning is low pressure on the roof itself, and whether the warranty is given in writing. A crew that reaches for a pressure washer on tile or shingles is a crew that can cost you a roof. Ask how plants and pets are handled too, since the solution has to go somewhere when it rinses off.
PressureLess serves Broward, Miami-Dade & Palm Beach counties from Miramar, Florida, is licensed and insured, and cleans roofs, driveways, patios, pool decks and gutters. You can read more about how we work or request a free estimate.
Common questions
- Is roof soft washing the same as pressure washing?
- No. Roof soft washing uses low pressure and a cleaning solution to remove algae, mold and staining at the source, so nothing is forced into your tiles or shingles. We do use pressure cleaning on flat, hard surfaces such as driveways, patios and pool decks, where higher pressure is appropriate.
- What surfaces and roof types do you clean?
- Roofs are soft washed, including tile, concrete and shingle roofs. Driveways, patios, pool decks and walkways are pressure cleaned, whether concrete or pavers. We also clean gutters. If you are unsure whether your roof or surface is a fit, send us a photo or give us a call and we will tell you straight.
- How are quotes determined?
- Quotes are based on the size of the area, the surface type and material, how much buildup there is, and access to the property. Estimates are free. Roof cleaning quotes start at $80 — the final price depends on your roof size, pitch and condition, so it is not a flat price for every roof.
- How should I prepare for an appointment?
- Move vehicles off the driveway and patio furniture off the deck if you can, and close windows facing the work area. We cover landscaping and plants before we start and rinse surrounding surfaces when we finish, so there is nothing special you need to buy or set up.