Soft washing vs pressure washing: which does your home need?

People use "pressure washing" as a catch-all, but the pros are really choosing between two very different techniques. Pick the wrong one and you can strip paint, carve lines into render or force water behind your cladding. Here's the plain-English difference and which surfaces need which.

What's the actual difference?

High-pressure washing uses water force to blast grime off hard, durable surfaces. It's the right tool for concrete, pavers and aggregate.

Soft washing uses low pressure — barely more than a garden hose — combined with cleaning solutions that kill mould, mildew, algae and lichen at the source. The chemistry does the work, not the force. It's the right choice for anything delicate or porous.

Which surface needs which?

Surface	Method
Concrete driveway, paths, aggregate	High pressure
Pavers & brick paving	High pressure (then re-sand)
Rendered / painted walls	Soft wash
Weatherboard, fibro, Colorbond cladding	Soft wash
Roof tiles & Colorbond roofing	Soft wash
Timber decks & fences	Low pressure / soft wash

The rule of thumb: hard and horizontal (driveways, paths) can take pressure; vertical, painted, porous or fragile (walls, roofs, timber) should be soft washed.

What goes wrong with the wrong method

• Render — high pressure chews through the top coat and leaves permanent wand marks.
• Paint & weatherboard — pressure lifts and flakes paint and can drive water into joints.
• Roofs — blasting strips the tile glaze and voids warranties, so moss returns faster. (More on that in our roof cleaning guide.)
• Windows & seals — over-pressure can breach seals and force water inside.

Why soft washing lasts longer

Because it kills the mould and algae rather than just knocking the surface layer off, a soft wash stays cleaner for longer — often twice as long as a blast that leaves the spores behind. For a full house exterior in Canberra, soft washing is almost always the safer, longer-lasting choice — see our exterior house washing guide for the full method and how often to do it.

What pressure are we actually talking about?

Method	Typical pressure	What's doing the work
Soft wash	Under 500 PSI, often hose pressure at the surface	The cleaning solution
Low-pressure wash (timber)	500–1200 PSI	Solution, with water assisting
Standard pressure wash	2000–3000 PSI	Water force
Concrete / surface cleaner	3000–4000 PSI	Water force and flow rate

The gap between the top and bottom of that table is roughly eightyfold. That's why "just turn the pressure down a bit" isn't soft washing — the two methods aren't points on a dial, they're different jobs with different tools and different chemistry.

How a soft wash is actually done

1. Prep. Windows closed, furniture moved, garden beds and lawn pre-wetted so runoff arrives diluted.
2. Apply low and work up. Solution goes on from the bottom upward, so concentrated product never runs down dry wall and streaks it.
3. Dwell. Ten to fifteen minutes, re-misted if it starts drying. This is the step doing the actual cleaning.
4. Agitate where needed. Lichen and heavy mould in sheltered corners get a soft brush — never more pressure.
5. Rinse top-down. Always angled downward on cladding and weatherboard, so water runs the way the boards shed it.
6. Rinse the surroundings. Plants, paths and anything that caught overspray.

Why soft washing is worth more than it looks

A soft wash can seem like less work than a high-pressure blast — there's no dramatic noise and no visible jet. What you're paying for is the chemistry, the knowledge of which solution suits render versus Colorbond versus roof tile, and the restraint not to damage a surface that can't be repaired. The visible result is similar on the day. The difference shows up eighteen months later, when the treated wall is still clean and the blasted one has gone green again.

FAQs

What is soft washing?

Soft washing is exterior cleaning that uses low pressure — barely more than a garden hose — combined with a cleaning solution that kills mould, algae, mildew and lichen at the root. The chemistry does the cleaning and the water only rinses, which makes it safe for surfaces that high pressure would damage.

What is the difference between soft washing and pressure washing?

Pressure washing uses water force to blast grime off hard, durable surfaces like concrete and pavers. Soft washing uses low pressure plus cleaning solutions to treat delicate, porous or painted surfaces like render, roofs, timber and cladding. The rule of thumb is that hard and horizontal surfaces can take pressure, while vertical, painted, porous or fragile ones should be soft washed.

Is soft washing better than pressure washing?

Neither is better outright — they suit different surfaces. On a concrete driveway, high pressure is the correct and far faster tool. On render, roof tiles, paintwork or timber, soft washing is the only safe option, and it also lasts longer because it kills the growth rather than knocking the visible layer off.

How long does soft washing last?

Typically twice as long as a high-pressure blast on the same surface, because the mould and algae are killed at the root instead of leaving spores behind to regrow. On a Canberra house exterior that usually means 18 to 24 months, or around 12 months on permanently shaded or south-facing walls.

Does soft washing damage plants?

Not when it is done properly. Garden beds and lawn adjacent to the work are pre-wetted so any runoff arrives diluted, and everything is rinsed thoroughly afterwards. Damage happens when undiluted solution is applied over dry soil and left, which is avoidable with basic preparation.

What pressure is used for soft washing?

Generally under 500 PSI, and often closer to standard garden-hose pressure of around 40 to 60 PSI at the surface. For comparison, concrete cleaning runs at 3000 to 4000 PSI. The low figure is the entire point — the cleaning solution is doing the work, not the water.