cleaning
Patio and decking cleaning
£80 to £120 cleans a 15 square metre concrete patio and £250 to £400 a large sandstone one. Rates run £3 to £8 a square metre by material. Decking is £4 to £8 a square metre, with oiling or staining a further £350 to £800.
What this covers
What it costs. Patio prices follow material, area and how much treatment the surface needs before the lance touches it. Full cost breakdown.
What the job covers
- Washing natural stone, porcelain and concrete
- Lifting moss and algae from joints
- Treating for regrowth after the wash
- Re-pointing or re-sanding where needed
- Sealing where the surface takes it
What is involved
Stone type changes the price more than area does. Concrete flags clean at £3 to £5 a square metre and porcelain at the same, while Indian sandstone and limestone sit at £5 to £8 because both are porous, hold black spot lichen and cannot take full pressure without pitting. Slate falls between at £4 to £7. A 20 square metre concrete terrace therefore costs £80 to £100 and the same terrace in sandstone £100 to £160.
What follows the wash is where quotes separate. Joints emptied by the lance need refilling, and kiln dried sand at around £1 a square metre or a brush in compound at £2 to £3 a square metre is the usual answer. Mortar pointing that has failed needs raking out and replacing at £15 to £25 a square metre, with labour at £150 to £250 a day. Sealing afterwards adds £3 to £8 a square metre and buys roughly twice as long before the next clean.
Timber follows different rules. Decking boards are softened by high pressure, so a wide fan nozzle held well back, or a cleaning solution and a stiff brush, protects the grain. Cleaning a small deck of up to 20 square metres costs £30 to £50 outside London and £40 to £80 inside it. Restoring the finish is the larger cost at £350 to £800 for oil or stain, plus £50 to £150 where boards need sanding first. Black spot treatment adds £2 to £4 a square metre on stone.
Choosing someone for the job
What is the stone, and what pressure will be used on it? Does the price include black spot or algae pre-treatment, and at what rate per square metre? Are joints refilled with kiln dried sand afterwards, and is that a separate line? Has failed pointing been quoted, or only cleaning? For decking, is the quote for a wash alone or for sanding and re-oiling as well?
Common questions
Will jet washing damage Indian sandstone?
Sandstone is porous and pits under a close, narrow jet, leaving a rough surface that holds dirt faster afterwards. Experienced contractors keep the lance back, use a rotary surface cleaner and pre-treat black spot with a chemical rather than pressure.
Is sealing a patio worth the extra?
Sealant adds £3 to £8 a square metre and roughly doubles the interval between cleans. Porous stone benefits most; dense porcelain gains little, and a sealed surface must be fully dry and clean before the coat goes on.