How often, by surface
- House siding: about once a year, or when you see green or black growth.
- Driveways and sidewalks: every one to two years, or after oil stains and mildew show.
- Decks and fences: once a year, and always before staining or sealing.
- Roofs: only when streaks or moss appear, and only with soft washing.
Signs it's time
- Green, black or gray streaks on siding
- Slippery walkways or patios
- Black streaks running down the roof
- Faded-looking paint that brightens when wet
Pressure washing vs. soft washing
High pressure works well on concrete and brick. On vinyl siding, painted wood, stucco and shingles, high pressure can force water behind siding, strip paint or damage the surface. Soft washing uses low pressure with cleaning solutions to kill mildew and algae, so it lasts longer on those surfaces.
Before the crew arrives
- Close windows and doors tightly.
- Move cars, grills, furniture and planters away from the house.
- Make sure an outdoor spigot works.
- Point out delicate plants and outdoor outlets.