Short answer
Soft washing relies on a cleaning treatment and lower pressure to break down grime and growth, while pressure cleaning uses the mechanical force of water to remove it. Neither is right for everything. The method should be chosen by the surface, its condition and any manufacturer guidance, not by habit.
Key points
- Soft washing leans on treatment and dwell time; pressure cleaning leans on water force.
- Aged paint, render, timber and sandstone need extra care, and even concrete can be damaged.
- Check roof material and manufacturer guidance before any roof is cleaned.
- Cleaning does not repair leaks or stop growth returning in damp, shaded spots.
What each method actually means
Pressure cleaning uses a focused stream of water, often with a rotary surface cleaner on flat areas, to physically lift dirt, mould and stains. It suits many hard, durable surfaces in sound condition.
Soft washing applies a suitable cleaning solution at low pressure, lets it work on the organic growth and grime, and then rinses it away gently. The cleaning comes mainly from the treatment and dwell time rather than force. The exact solution and pressure depend on the surface and what is growing on it, so there is no single universal figure.
Side by side
| Soft washing | Pressure cleaning | |
|---|---|---|
| How it cleans | Treatment and dwell time, low pressure rinse | Mechanical force of water |
| Often suited to | Painted walls, render, cladding, many roofs | Sound concrete, pavers, many hard surfaces |
| Main limits | Slower; runoff and nearby plants need care | Can etch, strip or force water where it should not go |
| Key questions | Is the treatment suitable for the surface? | Can this surface tolerate the force? |
Soft washing and pressure cleaning compared
How it cleans
- Soft washing:
- Treatment and dwell time, low pressure rinse
- Pressure cleaning:
- Mechanical force of water
Often suited to
- Soft washing:
- Painted walls, render, cladding, many roofs
- Pressure cleaning:
- Sound concrete, pavers, many hard surfaces
Main limits
- Soft washing:
- Slower; runoff and nearby plants need care
- Pressure cleaning:
- Can etch, strip or force water where it should not go
Key questions
- Soft washing:
- Is the treatment suitable for the surface?
- Pressure cleaning:
- Can this surface tolerate the force?
Surfaces that need extra care
Aged or chalky paint, render, timber cladding and sandstone can be marked or eroded by too much pressure. Concrete is not invincible either: older, coated or damaged concrete can be etched or have its finish stripped.
Windows, seals, electrical fittings, light fittings and wall or roof vents need protecting whatever the method. Even with care, no cleaner can honestly guarantee that water will never find its way into a gap that was already compromised.
Roof cleaning: check before you clean
Start by identifying the roof material and finish, and check the manufacturer's guidance and any warranty conditions. Recommendations differ between products.
- Monier advises against using pressure washers on its roof tiles, because they can damage the tile surface.
- For COLORBOND steel, the manufacturer refers owners to its technical bulletin TB27 for treating mould, fungus and lichen, rather than generic home recipes.
Please do not walk on your roof to inspect or clean it yourself, and do not attempt to pressure wash it. If there is any chance the roof contains asbestos, it needs assessment by a licensed specialist. Roof cleaning also does not repair leaks, broken tiles or failed coatings, which are restoration or repair work.
Brisbane's damp, shaded surfaces
South-facing walls, areas under trees and spots near downpipes stay damp after Brisbane storms and humid summers. These are the places where mould and algae return first. Cleaning removes the current growth, but no one can promise it will never come back while the conditions that encourage it remain.
Practical steps can slow regrowth: trimming branches that shade walls and roofs, keeping gutters and downpipes flowing, and fixing garden sprinklers that wet the same section of wall every day. Regular, gentle maintenance cleans are usually kinder to surfaces than waiting until growth is heavy and then needing a more intensive clean.
What a professional should assess
- The substrate, any old coatings and existing damage.
- Safe access, heights and how equipment reaches the area.
- Nearby plants, drainage, runoff and pets.
- Whether a spot test is sensible before the full job.
- A realistic outcome, including stains that may not fully lift.
Questions to ask and how to prepare
Good questions before booking:
- Which method will you use on each surface, and why?
- How will you protect windows, electrics, vents and gardens?
- What result is realistic for my surfaces?
- Does my roof material have manufacturer cleaning guidance?
Simple preparation that helps on the day:
- Close windows and doors and move outdoor furniture and pot plants.
- Keep pets and children inside or away from the work area.
- Let us know about any known leaks, cracked render or loose fittings.
- Make sure side gates and an outdoor tap are accessible.
Related services
Frequently asked questions
Is soft washing better than pressure cleaning?
Neither is better across the board. Soft washing suits many painted, rendered and roof surfaces, while pressure cleaning suits many sound, hard surfaces like concrete and pavers. The right choice depends on the material, its condition and any manufacturer guidance.
Can pressure cleaning damage concrete?
It can. Too much force or the wrong technique can etch the surface, leave stripes or strip sealers and coatings, particularly on older or damaged concrete. Controlled technique and a suitable surface cleaner reduce that risk.
Should my roof be soft washed?
It depends on the roof. The material and finish should be identified and the manufacturer's guidance checked first. Some manufacturers specifically advise against pressure washing their tiles, and metal roofing brands publish their own cleaning guidance.
Will soft washing stop mould coming back?
It removes the current growth, but mould and algae can return in damp, shaded areas over time. Improving drainage, sunlight and airflow where possible and scheduling regular cleaning helps keep it under control.
Do I need to be home during house or roof washing?
Not always, as long as we have access to the areas, water and power we need and windows are closed. We will confirm the details with you when booking.
Helpful references
- Monier: roof cleaning and maintenance (manufacturer guidance)
- COLORBOND steel: cleaning methods for fungus, mould and lichen (manufacturer guidance)
References are shared as general manufacturer guidance only and do not indicate endorsement of, or by, any brand.
