Test strip
Bottom: the roof before. Top: a test strip down the middle, part way through the job.
Slate roof cleaning
How we clean slate roofs
Slate is natural stone. It lasts 100 years or more, but it's brittle and cracks under foot traffic or harsh cleaning. We remove moss, lichen and algae with a low-pressure soft wash applied from ladders.
BeforeAfter
Sands Point, 2019. Drag to compare.
Never walked onAll work from ladders with standoffs
No pressureLow-pressure soft wash, no scrubbing or scraping
80–90% betterThe day we finish. Full result in 6 to 8 weeks
2-year guaranteeOn every full roof cleaning
Our process
We explain the process
Before any work starts, you know exactly what we'll do and what to expect.
We protect the property
Plants, gutters and copper get noted and protected. Landscaping is rinsed the whole time.
We soft wash from ladders
Low-pressure treatment applied from ladders. No one steps on the slate.
Weather finishes the job
The slate is not rinsed. Rain clears the dead growth over the next 6 to 8 weeks.
What we do
- Evaluate the roof and the type of growth
- Protect plants, gutters and copper before we start
- Apply a low-pressure soft wash from ladders
- Rinse the landscaping the whole time
- Inspect and clean up before we leave
What we never do
- Walk on the slate
- Pressure wash, scrub or scrape
- Rinse the treatment off the slate
- Force an instant result that risks the roof
Protecting your roof matters more to us than an instant before-and-after photo.
What grows on slate
Algae
Dark streaks and staining. Clears fastest.
Moss
Holds moisture against the stone. Common under trees and on shady slopes.
Lichen
Bonds tightly to slate. Scraping it damages the stone. The slowest to clear.
Rust stains
Removed with a completely different process. Ask about it with your quote.
What to expect
- 80 to 90% better the day we finish
- Full result in 6 to 8 weeks as weather clears the growth
- Most jobs take 1.5 to 5 hours
- Results usually last 4 to 8 years
- 2-year guarantee on full roof cleanings
Recent slate jobs
Before
AfterStone Tudor with a slate turret
A curved, conical slate roof cleaned evenly. Curved slate is some of the hardest to get right.
Before
AfterLarge brick estate, rear
The whole rear roof back to clean grey slate.
Before
AfterTudor with thick, textured slate
Heavy, hand-split slate cleaned without scrubbing or scraping.
Free quote
Find out what your roof needs
Call, text or send the form. Tell us the town and what you're seeing on the roof.
Call or text 631-433-2703
- We never walk on slate
- No pressure washing
- 2-year guarantee on full roof cleanings
- Licensed and insured, 13+ years in business
- Owner on every job