Professional roof cleaning in Ontario typically costs $300–$1,100, or about $0.25–$0.55 per square foot. A small bungalow roof runs $300–$500, while a large two-storey home reaches $800–$1,100 or more. Asphalt shingles must be soft-washed (low-pressure) — never pressure-washed — to protect the granules and your warranty.
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Roof Cleaning Cost by Roof Size
Roof cleaning is priced by roof area (square footage), pitch, and complexity. Most Ontario companies work out to roughly $0.25–$0.55 per square foot, with steeper, multi-facet roofs and heavy moss growth landing at the top of that range. Here is what homeowners across Kitchener-Waterloo typically pay in 2026.
| Roof size (footprint) | Home type | Price range (2026) | Notes |
|---|---|---|---|
| Up to 1,200 sqft | Small bungalow | $300–$500 | Single storey, simple roofline |
| 1,200–1,800 sqft | Average two-storey | $450–$750 | Moderate pitch |
| 1,800–2,500 sqft | Large two-storey | $700–$1,000 | Steeper or multi-facet |
| 2,500+ sqft | Large / luxury home | $1,000–$1,100+ | Multiple facets, dormers, complex access |
| Per square foot | Any | $0.25–$0.55 / sqft | Rate rises with pitch & moss load |
Rule of thumb: most single-family homes in KW fall in the $400–$800 range. Price rises with roof pitch, the number of facets and dormers, and how established the moss or lichen has become.
Why Asphalt Shingles Must Be Soft-Washed
This is the most important thing to know before hiring anyone: an asphalt shingle roof should never be pressure-washed. High-pressure water blasts the protective mineral granules off the shingles, which shortens their lifespan by years, forces water up under the shingles, and voids virtually every manufacturer warranty.
The correct method is a soft wash — low pressure (under roughly 500 PSI, similar to a garden hose) combined with a specialized cleaning solution, typically a diluted sodium hypochlorite mix. The solution kills algae, moss, and lichen at the root, then rinses clean. This is the method recommended by the asphalt shingle industry itself (ARMA — the Asphalt Roofing Manufacturers Association).
When you request a roof cleaning quote, ask directly: "Is this high-pressure or a low-pressure soft wash?" A reputable company will always answer soft wash for shingles. If a company proposes pressure-washing your shingle roof, that is a warning sign to walk away.
Pro Tip: The same low-pressure soft washing method that safely cleans your roof also works on vinyl siding, stucco, and painted surfaces — so it is often worth bundling a roof and siding wash in one visit.
Roof covered in black streaks or moss?
We soft-wash roofs safely across Kitchener, Waterloo, Cambridge & Guelph — no granule-stripping pressure. Free, no-obligation quotes, most ready within 2 hours.
Moss, Algae & Black Streaks
Those dark streaks running down Ontario roofs are not dirt — they are a blue-green algae called Gloeocapsa magma that feeds on the limestone filler in asphalt shingles. Left alone, it holds moisture against the roof and accelerates shingle breakdown. Green moss is even more aggressive: it lifts shingle edges and traps water, which is especially damaging through freeze-thaw winters.
Moss and algae grow fastest on shaded, north-facing, and tree-covered roof sections. A soft wash removes the current growth and the cleaning solution keeps it from returning for far longer than a simple rinse would. It restores the roof's appearance and, more importantly, protects the shingles you already paid for.
How Often Should a Roof Be Cleaned?
Most Ontario roofs benefit from a soft wash every 2–4 years, and sooner if black streaks or green moss start reappearing. Homes with lots of tree cover or shaded, north-facing slopes grow algae and moss faster and may need cleaning on the shorter end of that window. Regular cleaning is cheap insurance compared with premature shingle replacement.
What Affects Your Specific Price
Beyond roof size, several factors move a roof cleaning quote within its range:
- Pitch & height: Steep and tall roofs require more safety equipment and slower, more careful work.
- Complexity: Multiple facets, dormers, valleys, and skylights add time versus a simple gable roof.
- Growth severity: Thick, established moss and lichen need more solution and dwell time than light algae staining.
- Access & landscaping: Delicate plantings below the eaves may need protecting and rinsing, which adds setup time.
- Add-on services: Bundling gutter cleaning or a siding soft wash in the same visit is usually more economical than separate trips.
D&D Home Services provides safe, low-pressure roof cleaning and soft washing throughout Kitchener, Waterloo, Cambridge, and Guelph. Get your free quote — we typically respond within one business day.
Frequently Asked Questions
How much does roof cleaning cost in Ontario?
Most Ontario homeowners pay $300–$1,100 for professional roof cleaning, or roughly $0.25–$0.55 per square foot. A small bungalow roof runs $300–$500, an average two-storey $450–$750, and a large or complex roof $800–$1,100 or more. Price depends on roof size, pitch, number of facets, and how heavy the moss or algae growth is.
Can you pressure wash an asphalt shingle roof?
No. High-pressure washing strips the protective mineral granules off asphalt shingles, dramatically shortens their lifespan, forces water under the shingles, and voids most manufacturer warranties. Asphalt shingles must be cleaned with a soft wash instead.
What is soft washing a roof?
Soft washing uses low pressure (under about 500 PSI — similar to a garden hose) combined with a specialized cleaning solution, typically a diluted sodium hypochlorite mix, that kills algae, moss, and lichen at the root. It is the method recommended by asphalt shingle manufacturers (ARMA) and is safe for shingles, metal, and other roofing.
How often should a roof be cleaned?
Every 2–4 years for most Ontario homes, and sooner if you see black streaks or green moss returning. Homes with shaded, north-facing, or tree-covered roofs grow algae and moss faster and benefit from more frequent cleaning to protect the shingles.
Does roof cleaning damage shingles?
Not when it is done correctly with a soft wash. Low-pressure cleaning with the right solution removes algae and moss without disturbing the granules. Damage happens when a company uses high pressure on shingles — which is why method matters more than price when choosing a roof cleaner.
Ontario Roof Cleaning: 2026 Price Reference
- ✓ Small bungalow roof: $300–$500
- ✓ Average two-storey: $450–$750
- ✓ Large / complex roof: $800–$1,100+
- ✓ Per square foot: $0.25–$0.55
- ✓ Soft wash only — never pressure-wash asphalt shingles
- ✓ Clean every 2–4 years, sooner with visible streaks or moss
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