Patio Pressure Washing: Complete Guide
Cleaning a patio isn't just about blast-and-go. The right preparation, correct pressure settings and proper technique get a dramatically better result with less water and effort.
Step 1 — Clear and Prepare the Area
- Remove furniture, planters and decorative items
- Sweep to remove loose debris (gravel, leaves, sand)
- Cover any drains or gully gratings — the volume of dirty water and any detergent should be managed, not allowed to flow untreated into storm drains
- Wet surrounding plants — this dilutes any detergent overspray
Step 2 — Apply Patio Cleaner (Optional but Recommended)
For patios with algae, green slime or black spot lichen: apply a diluted patio cleaner or sodium hypochlorite solution (1 part bleach to 5 parts water) with a garden sprayer or the pressure washer's detergent function. Leave for 10–15 minutes. The chemical action loosens biological growth, making pressure washing significantly more effective and reducing water use.
Step 3 — Choose the Right Nozzle
40° fan nozzle: Wide, gentle — for rinsing and pre-wetting.
25° fan nozzle: Standard cleaning — most paved surfaces, stone, brick.
15° fan nozzle: Intensive — concrete and heavily soiled surfaces only. Never on wood, pointing joints, or render.
Rotary/turbo nozzle: A spinning water jet — extremely effective on concrete, driveways and stubborn stains. Much faster than a standard nozzle on large areas.
Surface cleaner attachment: A wide rotary disc attachment that cleans a large area uniformly without leaving track marks. Strongly recommended for large patio areas and driveways.
Step 4 — Wash Technique
- Work in overlapping, systematic rows — don't jump around randomly
- Keep the nozzle at a consistent distance (25–35 cm for most surfaces)
- Use slow, even strokes — moving too fast leaves dirt behind; too slow damages surfaces
- Work away from the building (push water outward, not toward walls and thresholds)
- On block paving and old pointing: avoid directing the jet directly at the joints — high pressure can displace sand and damage old mortar
Step 5 — Re-Sand Joints (Block Paving)
Pressure washing removes a proportion of joint sand. After washing and drying (1–2 days): sweep kiln-dried jointing sand into the joints, compact with a plate compactor or repeated foot traffic and watering, then apply a block paving sealer to prolong cleanliness.
FAQ
How often should I pressure wash my patio?
Once per year (early spring) is the standard recommendation. In shaded, damp conditions where algae grows quickly: twice yearly. After washing, applying a patio sealer or algaecide treatment significantly slows regrowth.