Roof Moss Removal & Treatment — Vancouver, Surrey & Lower Mainland

The Lower Mainland gives moss its three favourite conditions all at once. Persistent moisture (over 1,200mm of annual rainfall). Mild temperatures that never fully kill it off. Shaded north facing slopes under the constant canopy of Douglas firs, cedars, and big leaf maples. Add the fine organic dust that Vancouver air carries — pollen, bark debris, pine needles trapped between shingles — and you have a self feeding ecosystem. Asphalt shingle roofs on north facing slopes in Burnaby , North Vancouver , West Vancouver , parts of Coquitlam , and tree canopied streets in Surrey often show heavy growth within 8 to 12 years even on a brand new roof.

Real damage. Moss is not just sitting on the surface. Its root like structures (rhizoids) wedge under shingle edges, lifting them as the colony grows. Lifted shingles let wind driven rain underneath, accelerating underlayment failure. Saturated moss holds moisture against the shingle continuously, dissolving the asphalt binder and stripping the protective granules that block UV. Weight matters too. A heavily mossed roof can carry an extra 200 to 400 lbs of wet biomass that the structure was not designed for. Heavy growth typically reduces the practical life of an asphalt roof by 5 to 10 years compared to a clean equivalent.

Do not pressure wash an asphalt shingle roof. The high pressure stream strips the protective granules — exactly the layer that gives the shingle its UV resistance and lifespan. We see pressure washed roofs that needed full replacement within 5 to 7 years of the wash because the granule loss was so severe. Pressure washing also forces water under shingles in directions the roof was not designed to handle, creating immediate leak risk. Cedar shake roofs sometimes tolerate low pressure wash if done carefully, but even those are better treated with a soft brush approach. Soft wash chemical treatment is the correct method for asphalt.

Three steps in order. First, careful manual removal of the heavy growth using soft brushes (never wire brushes or scrapers that gouge granules). Second, application of a moss killing treatment — typically a zinc sulfate or copper sulfate solution, or a specialized roofing biocide. Third, installation of zinc or copper strips at the ridge, which slowly leach metal ions every time it rains, preventing regrowth on slopes below the strip for 10 to 20 years. The treatment kills existing moss; the strips keep it from coming back.

For a typical Lower Mainland single family home (2,000 to 2,500 sq ft), professional moss removal and treatment runs $400 to $900. Heavily mossed roofs with significant manual scraping work run $700 to $1,400. Adding ridge zinc strips for long term prevention adds $200 to $500 depending on roof linear footage. Cedar shake roofs cost more because of the careful handling required, typically $600 to $1,500. A well executed treatment plus zinc strip installation gives 3 to 5 years of meaningful protection before the next maintenance cycle.

Manufacturer warranties typically require professional cleaning methods that do not damage the shingle surface. CertainTeed , IKO , GAF, and Malarkey all explicitly prohibit pressure washing in their warranty terms. Soft wash chemical treatment performed by a certified contractor preserves the warranty. Annual inspections and maintenance like Paragon tune up service keep your warranty intact and catch moss before it becomes a problem.

Depends on your exposure. North facing roofs under tree canopy: every 2 to 3 years for moss treatment, plus annual inspection to catch regrowth early. South or west exposure with limited tree shade: every 4 to 6 years is usually sufficient. With zinc or copper strips properly installed at the ridge, you can extend these intervals by 50 to 100 percent. Cedar shake roofs need more frequent attention, annual inspection and treatment every 1 to 2 years.

Depends on three things. Roof age. Underlying shingle condition. How long the moss has been growing. If the roof is under 12 years old and the moss is recent (1 to 3 years of growth), proper removal and treatment will recover most of the remaining lifespan. If the roof is 18+ years old with heavy moss that has been there 5+ years, you are likely past the point where treatment is economical. The underlying shingles have lost too much granule and binder integrity. We provide free assessments that include this lifespan calculation honestly. Sometimes the answer is treatment. Sometimes it is replacement.

Yes. The same soft wash treatment that kills moss also addresses algae streaking (those black streaks running down north facing slopes), lichen patches, and general organic discolouration. Lichens are tougher than moss because they bond chemically to the granule surface, but the same chemistry kills them over 60 to 90 days. The streaking gradually fades with each rain after treatment as the dead biomass washes off. Most roofs look noticeably cleaner within 30 days of treatment and dramatically cleaner within 90 days.

Standalone. Many homeowners call us specifically for moss treatment, separate from any repair or replacement work. Our standalone moss removal includes inspection (we look for any underlying issues while we are up there), manual removal, soft wash treatment, ridge strip installation if requested, and a 30 to 60 day follow up application. We service all of Metro Vancouver and the Fraser Valley. Most jobs schedule within 2 to 4 weeks of your call.