How Often Should You Pressure Wash Your Home in Ontario?

Ontario's climate is hard on exterior surfaces. A long winter of road salt, freeze-thaw cycles, and ice is followed by a wet spring, a humid summer, and a fall that deposits debris into every joint and crack on your property. By the time you look at your driveway, deck, or siding in April, it's carrying the damage of an entire year.

How often you should pressure wash depends on the surface type, how exposed it is, and what you're trying to protect or preserve. Here's a practical breakdown by surface for GTA homeowners.

Cleaning Frequency by Surface

Surface	Recommended Frequency	Key Driver
Interlock / paver driveway	Every 1–2 years	Salt, efflorescence, weed growth
Concrete driveway	Every 1–2 years	Salt staining, oil, general grime
Wood deck	Every 1–2 years	Mould, mildew, grey weathering
Composite deck	Every 1–3 years	Mildew, algae growth in joints
House exterior (vinyl/brick)	Every 2–3 years	Mould, mildew, oxidation
Roof (soft wash)	Every 3–5 years	Algae (Gloeocapsa Magma), moss, lichen
Fence (wood)	Every 2–3 years	Mould, grey weathering, pre-stain prep
Flagstone / natural stone	Every 1–2 years	Algae, moss, efflorescence

Surface-by-Surface: What to Watch For

Driveways and interlock

The GTA's heavy road salt use is the main enemy of driveways. Salt leaves white efflorescence deposits, corrodes the surface over time, and accelerates weed growth in interlock joints. Most driveways benefit from an annual or biennial clean — more frequently if you notice significant efflorescence buildup or weed infiltration. If you're sealing your interlock, the seal itself needs to be in good condition for it to do its job, which means cleaning should come first.

Wood decks

Wood decks in Ontario are vulnerable to mould and mildew year-round, but the damage accelerates in spring when moisture levels are high. A deck that isn't cleaned and resealed every 1–2 years will grey out, develop surface mould, and begin to deteriorate at the board level. Cleaning in late spring — once temperatures are consistently above 10°C — gives you the ideal window before staining season.

House exterior

Most GTA homes don't need annual house washing, but 2–3 years is typically the point where mould, mildew, and oxidation become visible on vinyl siding, and green algae starts appearing on north-facing brick and stucco. North-facing walls and surfaces under tree canopy accumulate growth faster and may need more frequent attention.

Roofs

Roof cleaning is the most variable. Some roofs in shaded, humid GTA neighbourhoods develop visible algae streaks within 2–3 years; others in more exposed locations go 5–7 years before significant growth appears. The trigger for cleaning is visibility — once you can see dark streaks running down the slope, the algae is actively degrading your shingles and it's time to address it.

Signs You're Overdue — Regardless of Timeline

Schedules are a guide, not a rule. These signs mean you should book a clean regardless of when the last one was:

• Visible green or black biological growth on any surface — algae, moss, and mould are living organisms that cause active damage
• Significant efflorescence (white powdery deposits) on interlock or concrete
• Weeds establishing in driveway joints — once roots are established, they're harder to remove and cause joint erosion
• Slippery surfaces — algae on steps, patios, or decks is a safety issue beyond aesthetics
• Before sealing or staining — any protective product applied over a dirty surface is a waste of money
• Before listing your home — curb appeal directly affects first impressions and sale price

Does Cleaning More Often Actually Help?

Yes — within reason. Surfaces that are cleaned regularly are easier and cheaper to maintain than ones that are neglected for years. Organic growth that's been on a surface for one season comes off with far less effort than growth that's been establishing for five. This means shorter job times, lower cost, and less risk of surface damage from aggressive cleaning.

The exception is over-washing. Pressure washing wood surfaces too frequently — or at too high a pressure — accelerates grain raising and surface wear. For wood decks and fences, once a year is generally the right cadence unless you're dealing with a specific mould or staining issue.