Published June 28, 2026
Roof Cleaning Guide for Homeowners
How roof soft washing safely clears black streaks and moss from your shingles without the damage pressure washing causes.
Roof soft washing removes black streaks, moss, and algae from shingles using low-pressure application and a roof-safe cleaning solution, the same low-pressure approach used on siding. Pressure washing a roof can lift or damage shingles, which is why soft washing is the recommended method for asphalt shingle roofs.
What Causes Black Streaks on a Roof?
Those dark streaks are usually a type of algae called Gloeocapsa magma, which feeds on the limestone filler in asphalt shingles. It spreads gradually across the roof, typically starting on the north-facing or shaded side where moisture lingers longest.
How roof soft washing works:
Inspect
The roof is checked for moss, algae, and any areas needing extra attention.
Apply
A roof-safe, low-pressure cleaning solution is applied.
Dwell
The solution breaks down algae and moss at the root.
Rinse
The roof is rinsed at low pressure, removing the solution and growth.
Because soft washing relies on the cleaning solution rather than water force, it doesn't dislodge or damage shingle granules the way pressure washing can.
Removes
- Black algae streaking
- Moss buildup in shade
- Dirt and debris
- Lichen in some cases
Why Soft Wash, Not Pressure
- Pressure strips shingle granules
- Soft wash protects shingle life
- Kills growth at the root
- Results last 2 to 3 years
Is Roof Cleaning Worth It?
Beyond appearance, removing algae and moss helps prevent the kind of moisture retention that can shorten shingle lifespan over time. A clean roof also tends to reflect heat more effectively than one covered in dark algae streaking. For more on the streaking specifically, see our guide on how to remove black streaks from a roof.
Why Hire a Professional
Osborne Pro Wash is owner-operated and based in Morrow, Ohio, serving the Little Miami Valley including Maineville, Loveland, Kings Mills, South Lebanon, Landen, Lebanon, and Mason. Spray Wash Academy certified soft wash technique, safe for asphalt shingles, fully insured, with a satisfaction guarantee. See our roof soft washing service, or request a free quote below.
Roof Cleaning FAQ
Will pressure washing damage my roof?
Yes, it can. High pressure can lift or strip shingle granules, which is why soft washing is the recommended method for roofs.
Can roof cleaning remove moss completely?
Yes, in most cases. Soft washing breaks down moss at the root, though heavily established moss may need a follow-up treatment.
Does roof cleaning shorten shingle life?
No, when done correctly with the soft wash method. It's pressure washing, not soft washing, that risks shortening shingle life.
How long do roof cleaning results last?
Most roofs stay clean for 2 to 3 years after a soft wash, depending on shade and moisture exposure.
Get Your Roof Looking Clean Again
Request a free, no-pressure quote for safe roof soft washing.