Residential & commercial service
Roof Cleaning & Black Streak Removal
Roof cleaning removes the black streaks, moss, and lichen growing on shingle and tile roofs. We soft wash exclusively: a low-pressure application of sodium hypochlorite solution that kills the growth at the root, then a gentle rinse. A pressure washer never touches your roof, because high pressure strips shingle granules, cracks tile, and drives water under the roofing.
What Roof Cleaning Includes
We treat the full roof surface for algae, moss, and lichen, clear debris from valleys, and rinse runoff paths so the solution does not sit in your gutters or on your landscaping. Plants below the roofline are pre-wet, protected, and rinsed throughout the job. On tile roofs we work from ladders, edges, and walk pads wherever possible, because every unnecessary footstep on tile is a cracked tile waiting to happen.
Those Black Streaks Are Alive
The dark streaks running down shingle roofs are not dirt. They are Gloeocapsa magma, an airborne algae that feeds on the crushed limestone filler inside asphalt shingles. It spreads spore by spore, holds moisture against the roof, and slowly eats the shingle from the surface down. That is why streaks always come back after a cosmetic rinse: unless the organism is killed, it just regrows. Our soft wash solution kills it outright, which is the difference between cleaning a roof and briefly rearranging the algae.
Why Pressure Washing a Roof Is Always the Wrong Call
Asphalt shingles are surfaced with mineral granules that provide the UV protection, and high-pressure water strips those granules off in sheets, aging the roof years in an afternoon. Major shingle manufacturers specify low-pressure chemical cleaning for exactly this reason, and pressure washing can put your warranty at risk. Tile is no safer: pressure cracks tiles, dislodges them, and forces water past the underlayment into the structure. Soft washing at low pressure with sodium hypochlorite and surfactant cleans thoroughly with none of that risk. If anyone offers to pressure wash your shingle or tile roof, show them out.
Tule Fog Is a Roof Algae Machine
Roof algae needs moisture and shade, and Central Valley winters supply both for weeks on end. Tule fog keeps roof surfaces damp day and night, and north-facing slopes may never fully dry between December and February. That is why streaking out here often shows up heaviest on the north and east faces of the roof. Delta and Tri-Valley homes get a similar effect from year-round marine-influenced humidity. Once one roof on a street has it, spores carry to the neighbors, which is why streaks tend to appear across whole neighborhoods at once.
Cost Factors and When to Schedule
Roof size, pitch, height, roofing material, and severity of growth set the price. Steep or two-story roofs take more rigging and time, and heavy moss or lichen may need repeat treatment to fully release. You get a written flat quote before we start. As for timing, the best moment to clean is when streaks first appear, before the colony spreads and starts holding moisture. A properly soft washed roof typically stays clean for several years.
Questions We Actually Get
Will the cleaning solution damage my shingles?
No. Sodium hypochlorite solution applied at low pressure is the method shingle manufacturers themselves specify for algae removal. What damages shingles is the algae eating the limestone filler, and high-pressure washing stripping the granules. Soft washing removes the first threat without introducing the second.
How long will my roof stay clean after a soft wash?
Typically several years, because the treatment kills the algae rather than rinsing the surface. Regrowth timing depends on shade, moisture, and nearby infected roofs. Homes under heavy tree cover or in fog-prone pockets may see growth return sooner than homes in open sun.
Can you clean a tile roof without breaking tiles?
Yes, and it is a core part of how we work. Tile breaks under concentrated foot traffic, so we clean from ladders and roof edges wherever possible and distribute weight carefully when we must be on the roof. Soft washing helps here too, since low-pressure application means nobody is muscling a pressure wand across your tiles.
Is the runoff safe for my gutters, plants, and pets?
Yes, with proper management, which we build into every roof job. Landscaping is pre-wet and rinsed continuously, gutters and downspout paths are flushed, and pets should simply stay inside until surfaces are rinsed and dry. Diluted and rinsed, the solution breaks down quickly.
Does cleaning actually extend the life of a roof?
It removes an active cause of deterioration, so yes in a real sense. Algae, moss, and lichen hold moisture against the roof and physically degrade shingles, and moss can lift shingle edges enough to let wind-driven rain underneath. Killing that growth lets the roof do its job and can delay a replacement you do not need yet.
Ready to make it look new again?
Fast scheduling. Photo-documented results. A written quote before any work starts.