Pressure cleaning / Driveway · roof · render · soft wash

The wrong pressure on the right surface will permanently damage it. Most operators don't know the difference.

A 4000-PSI gun in untrained hands will strip render in twenty seconds, lift roof tiles off battens, and shear timber decking. The right operator knows which surfaces want high pressure, which want soft wash, and which want chemistry alone. This guide tells you which is which.

Driveway cost

$280–$650

Standard double driveway, concrete or pavers

Roof clean

$650–$1,800

Soft wash + treatment, single-storey tile

Render limit

800 PSI

Maximum safe pressure on standard acrylic render

Sources

39 verbatim buyer accounts; EPA water discharge guidelines; AS 4361 lead-paint disturbance; manufacturer specs (Karcher, Stratco, Spray Seal).

Verification

Pricing cross-checked against three operator quotes per state (Nov 2025–Apr 2026). PSI limits verified against manufacturer technical data sheets.

Funding

Independent. We don't take fees from operators or chemical suppliers. How this works.

Before we start

The phrase “pressure cleaning” covers two distinct techniques that should never be confused. High-pressure cleaning uses mechanical force to dislodge dirt — suited to concrete, brick, and unfinished masonry. Soft wash uses low pressure with biocides — suited to roofs, render, painted surfaces, and anything that fragments under impact. A good operator chooses; a bad one points the gun at everything.

What pressure cleaning costs

Pricing is per square metre, modified by access difficulty, surface type, and whether sealing or chemical treatment is included. The headline rate often doesn't include the chemistry, the sealer, or the disposal.

2026 price bands · by surface

Concrete driveway (clean only)	$3–$6/m²
Pavers (clean + sand reinstate)	$8–$14/m²
Roof tile (soft wash + treatment)	$5–$12/m²
Render / painted brick	$6–$14/m²
Timber decking (with brightener)	$10–$18/m²
+ Sealing (post-clean)	$8–$22/m²
Typical driveway visit	$280–$650

Two-storey roof access adds $200–$500. Bird-strike or moss treatment +20%. Minimum call-out usually $250.

How to vet a pressure cleaner

“

He cleaned the render and it looked great. Three weeks later we noticed lines — the paint had stripped right back to the bagging in patches. Cost $8,400 to re-render the front façade.

— Buyer, Inner West Melbourne VIC

Green flags

· Asks about surface type before quoting
· Distinguishes soft wash from high pressure
· Public liability $10M+, certificate available
· States PSI used for your specific surface
· Run-off / EPA disposal plan stated for chemicals

Red flags

· "We use 4000 PSI on everything"
· No insurance information offered
· Promises to remove all stains — no surface is universal
· Will pressure-clean pre-1970 painted surfaces without testing for lead
· No mention of stormwater drain protection

Lead paint, asbestos, chemical run-off

Pressure cleaning is unregulated as a trade — no licence required. But the materials you might be cleaning are very much regulated. Lead-painted surfaces and asbestos fibres become airborne / waterborne under pressure, and that triggers environmental law.

Three regulatory triggers

Lead paint (pre-1970 homes). Pressure cleaning lead-painted surfaces is regulated under AS 4361. Either test first or assume positive and use containment.
Asbestos cement sheeting. Pressure cleaning AC sheet eaves, garage walls, or fences releases fibres. Illegal in every state without proper containment and licensing.
Chemical run-off to stormwater. Hypochlorite, sodium hydroxide, and surfactants entering stormwater drains can trigger EPA fines $5,000+. Drain blocks & vacuum recovery required.

Part Two · Specifying the job

How often (and when not to)

· Driveway: every 12–24 months, more frequent if under trees
· Roof: 3–5 years (soft wash); never more frequently — you erode the surface
· Render & painted walls: annual gentle clean, not high pressure
· Decking: annual, ideally before resealing
· Pre-sale touch-up: 1–2 weeks before listing photos
· Don't clean: in heavy wind (overspray), within 24h of rain (mortar swelling), or in direct sun on dark surfaces (chemical flash)

High-pressure vs soft wash — the right tool

The two techniques solve different problems. High pressure removes physical deposits (dirt, lichen, paint). Soft wash kills biological growth (mould, mildew, algae) chemically, then rinses gently.

	High pressure	Soft wash
Typical PSI	2,500–4,000	100–500
Mechanism	Physical force	Chemistry + dwell time
Best for	Concrete, brick, unfinished masonry	Roof, render, paint, timber
Chemistry	Sometimes pre-treatment	Always — biocide / hypochlorite
Risk to substrate	High if misused	Low (chemistry-led)

Surface guide — driveway, roof, brick, render

Surface	Method	Max PSI
Plain concrete	High pressure + degreaser	4,000
Exposed aggregate	Medium pressure	2,200
Pavers (clay/concrete)	Medium + sand reinstate	2,000
Sandstone / soft stone	Soft wash only	500
Painted brick / render	Soft wash	800
Roof tile	Soft wash + biocide	600
Colorbond roof	Soft wash only	500
Timber decking	Low pressure + brightener	1,200
Vinyl windows	Hand wash only	N/A

What pressure cleaning can destroy

The damage list is longer than most owners realise — and most of it is invisible at the time of the clean.

· Render & paint stripped from walls. Not always obvious immediately — failure shows weeks later when sun cures the damage.
· Tile roof lifted off battens. Pointing damaged, water ingress in next rain.
· Mortar washed from brickwork. Older lime mortar especially.
· Timber decking shredded. Lifts the grain, splinters appear, requires sanding.
· Window frame seals breached. Water through to insulation cavity.
· Garden bed retaining beds. Pebble and mulch displaced into stormwater drains.
· Adjacent vehicles. Chemistry overspray damages paint — cover or move them.

Water restrictions and recycled water

Australian water restrictions vary by region and season. Some councils ban pressure cleaning of hard surfaces in drought-restricted periods — the operator should know your local rules.

Water-efficient operators

Modern professional units recycle water on-site, use tank-supplied water (not the mains), and feature reclaim systems. Drives up cost by ~$50/job but compliant with all restriction levels.

Stormwater protection

EPA requirement in NSW, VIC, QLD: drain blocks placed over stormwater pits during work. Wastewater vacuumed and disposed at trade waste facility. Ask operator about this directly.

Sealing after — the step most skip

A clean concrete or paver surface is also an unprotected one. The pores are open and ready to absorb whatever lands next — oil, leaf tannins, tyre marks. Sealing within 7 days of cleaning preserves the result and extends the cycle.

· Concrete sealer: $8–$18/m², lasts 3–5 years
· Paver enhancer + sealer: $14–$22/m², also stabilises joint sand
· Timber decking oil: $12–$20/m², annual recoat
· Roof tile sealer: usually packaged with the clean

Maintenance schedule & resealing cycle

· Year 0: Initial clean + seal
· Year 1: Light wash, no chemistry needed
· Year 2: Light wash, biocide on shaded areas
· Year 3: Full clean + reseal (depending on traffic)
· Year 5+: Strip and reseal cycle restarts

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