What is the main difference between soft washing and water blasting?

The fundamental difference is the mechanism of cleaning. Water blasting (pressure washing) uses high mechanical force, specifically water pressure, to physically remove contamination from a surface. Soft washing uses very low pressure combined with biodegradable chemical solutions to break down and kill biological organisms (mould, algae, lichen, bacteria) at the surface level. Soft washing cleans chemically; pressure washing cleans mechanically.

Which method is better for house washing?

For the exterior cladding of a premium home, soft washing is almost always the better choice. High-pressure washing can force water behind cladding systems, damage paint bonds, erode substrate edges and compromise surface coatings. Soft washing achieves a superior clean on biological growth, results last significantly longer, and the process carries much lower risk to painted and coated surfaces.

When is water blasting the right choice?

Water blasting is appropriate for durable hard surfaces, including concrete driveways, paths, brick, stone and heavy-duty pavers, where the surface can withstand mechanical force and where high-volume physical cleaning is the most effective approach. It is generally not appropriate for vertical cladding on buildings.

Does soft washing kill mould, or just remove it?

Soft washing kills biological growth at the root level, not just removes the visible surface layer. The biocidal agents in professional soft wash solutions penetrate and kill the organism, including the root-like attachments that anchor moss and lichen to surfaces. This is why soft washing results last significantly longer than water blasting. You're not just removing the symptom, you're treating the cause.

Is soft washing safe for all types of cladding?

Soft washing is safe for sound cladding of all common residential types, including painted weatherboard, fibre cement (Hardiplank, James Hardie products), plaster/render systems, cedar, vertical shiplap, brick and metal cladding. Where cladding is in poor condition, such as significant paint failure, cracking or a compromised surface, any washing method requires care, and we assess condition before proceeding.

How long do soft washing results last compared to water blasting?

Professional soft washing typically keeps a surface clean two to four times longer than water blasting. The reason is the biocidal action: biological growth is killed rather than just removed, and the inhibitory effect of professional cleaning solutions continues to suppress regrowth for an extended period. A water-blasted surface that still has viable biological residue in microscopic surface pores will recolonise much faster.

Do you always use soft washing for house exterior cleaning?

Soft washing is our primary and preferred method for exterior cladding on premium homes. There are situations where controlled pressure washing is appropriate for specific areas, such as certain hard surface elements at ground level, but for the painted or coated exterior cladding of a high-value home, soft washing is our standard approach.

Method Guide · Auckland

Soft Washing &Water Blasting: What's Right for Your Property?

The method used to clean your property's exterior matters more than most homeowners realise. Choose the wrong one and you risk damaging paint, cladding and surface coatings. Choose correctly and you get a cleaner result that lasts significantly longer. Here's how to tell the difference.

Soft washing uses low water pressure and biodegradable biocidal cleaning solutions to kill and remove biological growth, including mould, algae, lichen and bacteria, from surfaces without the mechanical risk of high pressure. Water blasting (pressure washing) uses high-pressure water flow to physically remove contamination from durable surfaces. For premium home exterior cladding, soft washing is almost universally the correct method. Water blasting is appropriate for hard ground-level surfaces like concrete driveways and paths. Prevent Maintenance uses soft washing as the primary method for exterior cladding on all high-value homes.

Method Comparison

Understanding the difference

Recommended for Premium Homes

Soft Washing

Low-pressure application of biodegradable biocidal cleaning solutions. Kills biological growth at root level and inhibits regrowth. The standard for exterior cladding on high-value homes.

Pressure typically well below damage threshold

Biocidal agents kill mould, algae and lichen at root level

Results last 2–4x longer than pressure washing

Safe for all painted and coated cladding types

No risk of water ingress behind cladding

Inhibits regrowth, not just removes visible growth

Biodegradable solutions: low environmental impact

Best for

Exterior cladding on houses, roofs, painted surfaces, weatherboard, fibre cement, plaster, cedar and all soft or coated surfaces.

For Hard Surfaces Only

Water Blasting / Pressure Washing

High-pressure water flow removes contamination through mechanical force. Effective on durable hard surfaces; carries significant risk for vertical cladding, painted surfaces and coated materials.

High mechanical force, effective on hard surfaces

Does not kill biological growth. Removes surface layer only.

Regrowth returns faster. Organisms remain in surface pores.

Risk of forcing water behind cladding on buildings

Can damage paint, erode tile surfaces and raise timber grain

Risk of flashing and sealant disturbance at high pressure

Appropriate for concrete, brick, stone and durable pavers

Best for

Concrete driveways, paths, brick pavers, stone surfaces and other durable hard ground-level surfaces. Not recommended for exterior cladding.

Why It Matters for Premium Homes

The risks of pressure washing a premium home

High-pressure washing has become default for exterior cleaning largely because it is quick and visually satisfying. You can see contamination being removed in real time. But for vertical cladding on a building, this creates risks that experienced property owners have learned to avoid.

At pressures used in typical pressure washing, water can penetrate gaps in cladding systems, joints, and seals that would repel rain under normal conditions, because rain falls at low velocity and does not have the directional force of a pressure washer directed at a joint. Water forced behind cladding creates moisture in the wall cavity, which creates conditions for framing damage and potential weathertightness issues.

For painted and coated surfaces, excessive pressure can compromise paint adhesion, particularly at edges, laps and joints. The result may not be immediately visible but manifests as accelerated paint failure in the weeks and months following the wash.

On a premium home, these are not acceptable risks. Soft washing delivers a superior result without any of them.

Pressure Washing Risks on Premium Homes

Water ingress behind cladding

High-pressure water directed at cladding joints, window seals and horizontal laps can penetrate through gaps that resist normal rainfall.

Paint adhesion damage

Excess pressure at paint edges and laps can break the adhesion bond, leading to accelerated peeling and paint failure.

Timber grain damage

On timber weatherboard and decks, excessive pressure raises the grain and fibres, damaging the surface and reducing the life of any subsequent surface treatment.

Faster biological regrowth

Pressure washing removes visible growth but leaves viable organisms in surface pores. Biological growth returns faster than after soft washing.

How We Decide

Method selection at every property

Surface

Exterior cladding (painted weatherboard, fibre cement, plaster, cedar)

Soft wash

Protects surface coating, prevents water ingress, superior result on biological growth.

Surface

Roof (all types)

Soft wash / low pressure

Protects roofing material, coatings and granules. Biocidal treatment inhibits regrowth.

Surface

Timber deck and fence

Controlled pressure + cleaning agents

Method calibrated to timber species and condition to clean without raising grain.

Surface

Concrete driveway and paths

Water blasting

Durable surface tolerates pressure. Effective removal of heavy staining and algae.

Surface

Brick pavers

Adjusted pressure

Sand-set pavers require care to avoid disturbing joint sand. Reduced pressure.

Surface

Exposed aggregate or sealed concrete

Adjusted pressure

Surface finish determines appropriate pressure. Assessed individually.

Frequently Asked

Soft washing and water blasting questions answered

Related Services

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Soft Washing &Water Blasting: What's Right for Your Property?

Understanding the difference

Soft Washing

Water Blasting / Pressure Washing

The risks of pressure washing a premium home

Pressure Washing Risks on Premium Homes

Method selection at every property

Soft washing and water blasting questions answered

House Washing

Roof Care

Deck, Fence & Hard Surface Cleaning

Building Washing

We'll assess your property and use exactly the right approach