Chemistry kills the mould. Pressure just moves it.
Soft washing applies detergent at low pressure, kills mould, algae and lichen at the root, then rinses gently. It is the standard for weatherboard, render and brick, and the only safe method for the plaster cladding across Christchurch's post-quake repair stock, where nor'westers already drive rain into wall junctions. One operator publishes fixed menus from $319, windows included.
Is this your stream?
Mould, algae or lichen on cladding, a pre-paint or pre-sale exterior reset, or the annual wash that keeps regrowth from winning. Any cladding type: weatherboard, render, brick, and especially plaster.
Moss on the roof is roof treatment, a spray-and-leave chemical job. Driveways, paths and patios are water blasting, the one place high pressure belongs.
What soft washing costs in Christchurch
Christchurch has unusually good price transparency: one operator publishes full fixed menus. Use them as an anchor; the rest quote per job.
$319–$649
Published menus with Resene detergent: single-level 2-bed $319 to 5-bed $429, two-storey $389 to $549. Pure-water (water-only) washes run $369 to $649. A free exterior window clean is included.
$200–$700+
Published Christchurch ranges: small unit $200 to $250, 2-bed $250 to $350, 3 to 4 bed $350 to $500, 4+ bed $500 to $700, extra-large or multi-level from $700+. Storeys and access move quotes between bands fast.
From ~$590+GST
Roof treatment adds about $250+GST; driveways run $100 to $300. Published bundles combining house wash, roof treatment and driveway start from about $590+GST for homes up to 150m², one visit, lower total.
Christchurch soft wash providers, compared
Published-menu operators, local specialists and the franchise systems. Hover a row for the detail that matters.
Choose by situation
Reflections publishes its full menu by size and storeys with a free exterior window clean included. Budget $319 to $649 before anyone visits, then compare other quotes against it.
Say so when you quote, and accept only soft wash. Canterbury's nor'westers drive rain into wall junctions already; high pressure makes it worse. TLC Softwash's workmanship guarantee and Chemwash's 40-plus years of low-pressure systems fit this housing stock.
Salt air and shade shorten the cycle. Southern Wash Worx runs customised maintenance plans across all suburbs including coastal; YourLocal covers Akaroa to Rangiora as an eco owner-operator.
Bundle: roof treatment, driveway and windows with the wash. Wash Rite packages windows and spider treatment; published bundles start around $590+GST. One crew beats three callouts.
Common mistakes
Water blasting plaster or monolithic cladding: Canterbury's nor'westers already drive rain horizontally into wall junctions, and high pressure forces more water in. Much of Christchurch's post-quake repair stock is plaster-clad. Soft wash is not a preference here; it is the safe method.
Assuming the house wash includes the roof: a standard wash runs gutter-line to ground. Roof treatment adds about $250+GST and bundles far cheaper than a second callout. Ask explicitly what the quote covers.
Letting mould go for years: a professional wash lasts 12 to 24 months before regrowth. Shaded southern walls and tree-heavy sections regrow faster, and annual washing prevents the buildup that turns a $350 wash into a restoration job.
Ignoring water restrictions: Christchurch's summer restrictions can halt outdoor water use. Check the current level before any DIY wash, and ask operators how they work within the rules.
Forgetting coastal salt air: New Brighton, Sumner and the coastal strip need shorter cycles, sometimes six-monthly. A standard annual plan under-serves a coastal property.
Booking on sticker price without stating cladding type, storeys and access: two-storey and multi-level homes jump price bands fast. Reflections' published menus split single-level ($319 to $429) from two-storey ($389 to $549) for exactly this reason.
FAQ
How much does soft washing cost in Christchurch?
Reflections publishes fixed menus: with Resene detergent, single-level 2-bed $319 to 5-bed $429, two-storey $389 to $549, and pure-water washes $369 to $649, with a free exterior window clean included. Wider published Christchurch ranges run $200 to $250 for a small unit, $350 to $500 for a 3 to 4 bed, up to $700+ for extra-large or multi-level homes. Roof treatment adds about $250+GST.
Soft wash or water blasting for the house?
Soft wash, always, for cladding. Low pressure plus chemistry kills mould, algae and lichen at the root and is safe on weatherboard, render, brick and plaster. High pressure belongs on driveways and concrete only: it strips paint and drives water behind cladding, a genuine risk on Christchurch's plaster repair stock under nor'wester-driven rain.
How often should a Christchurch house be washed?
Annually suits most homes; a professional wash typically lasts 12 to 24 months before regrowth. Shaded, tree-heavy or coastal properties (New Brighton, Sumner) may need six-monthly cycles. Nor'wester dust events are a legitimate trigger for an off-schedule wash.
Is soft washing safe for gardens and pets?
The chemistry is applied diluted and rinsed, and reputable operators pre-wet and protect planting, but it is still a chemical process. Ask what is being applied (Reflections uses Resene detergent), how gardens are protected, and keep pets inside during application.
What should I ask before booking?
State cladding type (especially plaster), storeys, access and any leak history. Ask whether the price includes GST and windows, what chemistry is used, how runoff is managed, whether roof treatment or driveway can be bundled, and what the workmanship guarantee covers.
Price transparency goes to Reflections ($319 to $649 published, windows in). Local specialists go to YourLocal, TLC Softwash and Southern Wash Worx (maintenance plans for coastal and shaded homes). Proven systems go to Chemwash Canterbury and Wash Rite. Never put high pressure on plaster cladding, declare your cladding type when quoting, ask about the chemistry, and bundle roof and driveway when the whole exterior is due.