How Much Should Roof Cleaning Cost?

Professional roof cleaning in London, Ontario typically costs approximately $500 to $1,500+, depending on the size, height, pitch, material, accessibility, complexity, and condition of the roof. A smaller roof with relatively light organic growth may cost approximately $500 to $750, while an average two-storey home may fall around $700 to $1,000. Large homes, steep roofs, three-storey properties, complicated rooflines, and roofs with significant moss, lichen, algae, or other organic growth can cost $1,000 to $1,500 or more. Unlike cleaning a driveway or other durable hard surface, roof cleaning requires specialized techniques because roofing materials generally should not be subjected to aggressive pressure washing.

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Asphalt Shingle Roof Cleaning Costs

Asphalt shingles are one of the most common roofing materials found on homes throughout  Southwestern Ontario. Over time, shingles can develop black streaks and discoloration associated with algae, along with moss and lichen in shaded or damp areas. Asphalt shingles should generally be soft washed rather than pressure washed. Instead of attempting to blast organic growth from the roof with high pressure, professional soft washing uses an appropriate cleaning solution and controlled low-pressure application to treat the contamination. Pricing depends heavily on the total roof area, pitch, number of sections, severity of organic growth, and how safely the roof can be accessed. These roofs are often the easiest to work with and on average run from $500 to $1,500.

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Metal Roof Cleaning Costs

Metal roofs can also accumulate algae, mildew, dirt, pollen, bird droppings, and environmental buildup. Although metal is a durable roofing material, that does not mean maximum pressure should automatically be used to clean it. Painted and coated metal roofing can require a more controlled cleaning process to avoid unnecessarily affecting the finish. Metal roofs can also become extremely slippery when wet, which can make access and cleaning more complicated. A large or steep metal roof may therefore cost more than expected because the quote needs to account for the size of the roof, pitch, coating, contamination, surrounding property, and the safest method of completing the cleaning. These roofs are a little more complicated than asphalt and on average run from $1,000 to $2,500.

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Cedar Shake and Specialty Roof Cleaning

Cedar shake roofs require a considerably different cleaning approach from standard asphalt shingles. Cedar is a natural wood product, and excessive pressure can scar the wood, raise the grain, or damage weathered fibres. Depending on the condition of the cedar, cleaning may be part of a larger restoration process involving wood-specific cleaners, controlled rinsing, brightening, and potentially additional restoration or oiling. Slate, clay tile, concrete tile, synthetic roofing, and other specialty roof systems should also be evaluated individually. Some materials can be fragile under foot, while others have specific coating or cleaning requirements. Because these roofs require more specialized knowledge and care, pricing can fall outside the range of a straightforward asphalt shingle roof cleaning. These roofs are quite a bit more complex than asphalt or metal roofs and and on average run from $6,000 to $25,500.

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Why Roof Height, Pitch and Organic Growth Affect the Price

The physical design of the roof can have just as much influence on the cost of roof cleaning as the material itself. A simple, low-pitch bungalow roof is generally easier to treat than a steep two-storey or three-storey roof with multiple peaks, valleys, dormers, skylights, additions, and difficult-to-access sections. Walkout basements can make rear elevations significantly higher than they appear from the front of the property. The amount of contamination also matters. Light black algae staining can require less treatment than a roof covered with substantial moss and lichen. Heavy growth may require additional solution, treatment time, and follow-up attention, and some dead moss or lichen may release gradually after treatment rather than being aggressively removed from the roof.

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Why Soft Washing Is Used Instead of Pressure Washing a Roof

For many residential roofing systems, soft washing is the preferred alternative to high-pressure roof washing. The objective is to use the appropriate cleaning chemistry to treat algae, moss, lichen, and other organic contamination rather than attempting to physically remove everything with excessive water pressure. High-pressure washing can potentially damage shingles and other delicate roofing materials, which is why the cleaning process used on concrete should not simply be transferred to a roof. A professional roof cleaner should evaluate the roofing material and condition before determining the appropriate cleaning method, solution strength, application process, and rinsing requirements. The goal is to achieve an effective clean while minimizing unnecessary mechanical force against the roofing system.

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Typical Roof Cleaning Prices in London, Ontario

As a general starting point, homeowners can expect professional roof cleaning in London, Ontario to cost approximately $500 to $1,500+. Smaller and relatively straightforward roofs may fall around $500 to $750, average residential roofs may cost approximately $700 to $1,000, and large, steep, complicated, or heavily contaminated roofs may range from $1,000 to $1,500 or more. Cedar shake, slate, tile, unusually steep metal roofs, and other specialty roofing systems should generally be evaluated and quoted individually. Ultimately, the most accurate roof cleaning price should consider the roof's square footage, pitch, number of storeys, roofing material, accessibility, complexity, and severity of algae, moss, and lichen growth rather than relying on the home's interior square footage alone.