Why BC Homes Need More Frequent Cleaning Than Most
The Fraser Valley sees consistent rainfall from September through May, overcast skies for much of the year, and mild enough winters that moss and algae don't die back the way they would in colder climates. The result: biological growth builds up year-round on roofs, siding, decks, and driveways — and it builds up faster here than in drier parts of Canada.
The homes that hold up best over time are the ones where owners stay ahead of the buildup. Once moss, lichen, or mildew is well-established, removal is more involved — and the damage it causes (to shingles, paint, sealant, and wood fibres) compounds the longer it sits.
General rule: if you can see it from the ground, it's already been growing for a while. Early cleaning is always faster, cheaper, and less invasive than letting it go.
Cleaning Frequency by Surface
House Siding (All Types)
Every 1–2 yearsVinyl, Hardie, stucco, and wood siding in the Fraser Valley typically show visible mildew, oxidation, or green algae within 1–2 years — especially on north-facing walls or those shaded by trees. Soft washing annually or every other year keeps it manageable and prevents permanent staining.
Asphalt Shingle Roof
Every 2–4 yearsA professionally soft-washed roof stays clean for 2–4 years in most BC climates. Roofs with heavy moss growth, north-facing slopes, or significant tree coverage may need attention every 2 years. Annual inspection is worth doing — look from the ground or a ladder at the eave line each fall.
Cedar Shake Roof
Every 1–3 yearsCedar is more vulnerable than asphalt and needs more frequent attention. Moss and lichen grow faster on cedar and cause more damage — physically cracking and rotting the wood over time. Regular soft washing is part of what keeps cedar shake roofs viable long-term.
Deck & Fence (Wood)
Every 1–2 yearsWood that sits in BC's climate without regular cleaning grays out, grows mildew between boards, and becomes slippery. Cleaning every 1–2 years maintains the appearance and — if you plan to stain or seal — cleaning first makes a significant difference in how long the finish lasts.
Concrete Driveway & Walkways
Every 2–3 yearsConcrete is durable but still collects moss, algae, tire marks, and ground-in dirt. In shaded driveways, moss can build up in as little as a season. A pressure wash every 2–3 years keeps things clean and removes slip hazards.
Gutters (Interior Cleaning)
1–2 times per yearThis one's about function, not looks. Gutters in the Fraser Valley collect significant leaf and debris buildup — especially under Douglas firs and cedars. Blocked gutters overflow against the fascia and foundation. Most homes benefit from a clean in late fall and a check in early spring.
Factors That Increase How Often You Should Clean
These are the most common factors that mean your home needs cleaning more frequently than the averages above:
The Best Time of Year to Clean in the Fraser Valley
Timing matters, especially for preventive cleaning. Here's what tends to work well:
Spring (March–May)
Best for post-winter cleaning. Remove growth that built up over the wet season before it fully dries and bonds. Good for driveways, siding, and decks before outdoor season.
Late Summer (August–September)
Best for preventive roof and gutter work before the fall rains. Getting growth off before the wet season prevents it from holding moisture over winter.
Fall (October–November)
Good for gutter cleaning after the leaf drop. Also catches any late growth before winter sets in.
Winter (December–February)
Generally not ideal — cold and wet conditions slow treatment effectiveness and make roof and height work more hazardous. We may still do flat surfaces when weather cooperates.
What Happens If You Wait Too Long?
The honest answer: cleaning costs go up, and so does the risk of permanent damage.
Moss that's been on a roof for 5+ years has penetrated deeply into shingle material. Lichen bonds chemically to roofing and siding surfaces — at a certain point, full removal isn't possible without also removing some of the surface itself. Long-established mildew on wood causes permanent discolouration and accelerates rot.
Regular maintenance is genuinely cheaper than letting things go. A cleaning every couple of years costs a fraction of what early shingle replacement, siding repainting, or deck board replacement costs.