How long does it take to pressure wash a patio?

A typical UK patio of 20-30 m² takes 2-4 hours to pressure wash properly. This includes pre-treatment with detergent, pressure washing, and a final rinse. Block paving takes longer than slabs due to the joints. Natural stone requires slower, more careful cleaning.

Should I use detergent when pressure washing a patio?

Yes, applying a specialist patio cleaning detergent or biocide before pressure washing significantly improves results. It breaks down algae, moss, lichen and organic staining. Apply, allow 15-30 minutes dwell time, then pressure wash. This reduces the pressure needed and protects the surface.

How much water does patio cleaning use?

A typical domestic pressure washer uses 6-8 litres per minute. Cleaning a 25 m² patio at a rate of 8 m²/hr would use around 350-450 litres of water over 3-4 hours. Using a rotary surface cleaner attachment reduces water splashing and can improve efficiency.

How often should a patio be pressure washed?

Most UK patios benefit from pressure washing once or twice a year — typically in spring and autumn. Applying a biocide treatment after cleaning helps prevent regrowth of algae and moss, extending the time between cleans. North-facing or shaded patios may need more frequent attention.

CleanCalcs

Patio Cleaning Calculator

Calculate time, water usage and detergent for patio and paving cleaning.

Patio Area

Total patio area

Surface Type

Flow Rate

Your pressure washer flow rate

Detergent Cost per Litre

Optional

How We Calculate This

How the calculation works

Cleaning time is estimated from the area and a coverage rate that varies by surface type.

Coverage rates (m² per hour)

Concrete slabs: 8 m²/hr
Natural stone: 6 m²/hr
Block paving: 5 m²/hr
Porcelain paving: 10 m²/hr

Formulae

Time = area ÷ coverage rate

Water = time (hrs) × flow rate (L/min) × 60

Detergent = area × usage rate per m²

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities and timings for your specific situation.