Roof Cleaning and Coating
Low-pressure soft-wash to remove moss, algae and lichen. Zinc-based protective coating extends shingle life. Warranty-safe.
What We Offer
Those black streaks are eating your roof
Dark streaks on Edmonton shingle roofs are not dirt — they are gloeocapsa magma, an algae that feeds on the limestone filler in shingles. Left untreated, it shortens roof life by 5 to 10 years.
Soft-washing is the only warranty-safe cleaning method. High-pressure power-washing strips the protective ceramic granules and voids manufacturer warranties. River Valley Contracting uses sodium-hypochlorite cleaning solution at under 300 PSI.
After cleaning we can install zinc or copper strips at the ridge for 8 to 10 years of regrowth prevention.
Get a Free Quote
Full Scope of Work
Everything included in the price
No hidden extras. Every item below is included in your written estimate.
Roof inspection
Walk and photograph the roof, identify shaded slopes and existing damage. Free quote follows the same day.
Landscape protection
Plants pre-wetted, sensitive plants covered, drains protected. Adjacent windows masked.
Soft-wash application
Biodegradable sodium-hypochlorite solution applied at low pressure. Dwell time per manufacturer spec.
Light rinse
Low-pressure rinse. Granules and seal strips left intact. Warranty unaffected.
Zinc strip option
Strips installed at the ridge for 8 to 10 years of algae prevention.
Photo documentation
Before-and-after photos for your records and resale documentation.
Frequently asked
Common questions
Will my shingles look new again?
Almost. Black staining disappears completely after a soft-wash. Granule loss that has already happened cannot be reversed but cleaning prevents further degradation.
How often should I have this done?
Every 4 to 6 years for most Edmonton homes. Heavy tree cover or north-facing slopes may need it every 3. Zinc strips extend the interval to 8 to 10 years.
Is high-pressure ever OK on a roof?
No. It strips granules, shortens roof life and voids most manufacturer warranties. River Valley Contracting never uses high-pressure on shingle roofs.
Are the chemicals safe for plants?
When landscaping is pre-wetted and rinsed thoroughly post-treatment, yes. We avoid windy days.
Do you coat flat commercial roofs?
Yes — reflective white elastomeric coatings extend ageing membrane life by 10+ years and reduce cooling load.
Will paint extend a shingle roof?
No — paint will not bond reliably to asphalt shingles and voids the warranty. Soft-wash plus zinc is the correct treatment.
Ready to start your project?
Free written estimate from River Valley Contracting. No deposit. Same business day response.