Pressure washing vs soft washing.
The single most important decision in any exterior clean is which method to use on which surface. Get it wrong and you damage render, strip roof glaze or just watch the mould grow straight back. Here is how to choose, for a Pakenham home.
Two different jobs, often confused.
People use pressure washing as a catch-all term, but there are really two methods and they do different things. Pressure washing uses high water pressure, 2,000 to 4,000 PSI, to physically blast dirt, grime and surface growth off a hard surface. It is fast and effective on concrete, pavers and brick. Soft washing uses low pressure, under 500 PSI, combined with a biodegradable detergent that chemically kills mould, algae and lichen at the root, which is then rinsed gently away.
The crucial difference for a damp climate like Pakenham’s is what happens afterwards. High pressure removes the visible growth but the living spores are in the surface, so it returns within a season. Soft washing kills the growth, so the surface stays clean for a year or more.
Use pressure washing on these surfaces.
- Concrete driveways and paths: the classic high-pressure surface, see driveway cleaning.
- Exposed aggregate: pressure washed, but with an even flat-head pass so stones are not dislodged.
- Paver paths and brick: pressure cleaned, then joints re-sanded.
- Hard commercial surfaces: car parks, warehouse aprons, loading docks, see commercial pressure washing.
Use soft washing on these surfaces.
- Acrylic render: the most common Pakenham estate cladding, and the one most often damaged by high pressure. See house soft washing.
- Painted weatherboard and fibre cement: high pressure lifts and flakes paint.
- Roof tiles, terracotta and concrete: high pressure strips the glaze and forces water inside, see roof cleaning.
- Colorbond and steel roofs: soft washed to avoid scratching the coating.
Why this matters so much in Pakenham.
Pakenham’s cool, damp climate and heavy tree cover mean organic growth, mould, algae and lichen, is the main thing we clean, far more than simple dirt. That tips the balance heavily toward soft washing for houses and roofs, because killing the growth is the whole point. The newer estate homes across Cardinia Lakes, Lakeside and Officer are almost all render, which must never be high-pressured. A washer who only owns a pressure lance and uses it on everything will eventually damage a render wall or a tile roof in this town. The right answer is both methods, chosen per surface.
Method questions.
What is the difference between pressure washing and soft washing?
Pressure washing uses high pressure (2,000 to 4,000 PSI) to blast dirt off hard surfaces. Soft washing uses low pressure (under 500 PSI) plus a detergent that kills mould, algae and lichen at the root, then rinses it away. One removes grime by force, the other kills living growth so it does not return quickly.
Should my render house be pressure washed or soft washed?
Soft washed, always. Acrylic render has a thin texture coat that high pressure strips off, and the pressure forces water into the wall. The same applies to painted weatherboard, fibre cement and roof tiles.
Is soft washing better than pressure washing?
Neither is better overall, they suit different surfaces. Pressure washing is right for concrete, pavers, brick and hard commercial surfaces. Soft washing is right for render, weatherboard, roof tiles and Colorbond. A good operator uses both.
Does soft washing last longer?
On mould, algae and lichen, yes. Because it kills the spores rather than just removing the surface, a soft-washed Pakenham house or roof stays clean 12 to 24 months or more, where high pressure alone can green up again in one damp season.
Related guides and services.
Not sure which method you need?
Send a photo and we will tell you straight, soft wash or pressure, and price it.