Auckland has a humid subtropical climate. That means warm, wet summers and mild damp winters — perfect conditions for mould, algae, and lichen to grow on your home's exterior. If you are not washing your house regularly, you are probably letting these organisms slowly damage your paint and cladding.
So how often should you wash? It depends on the surface and your location.
House Exterior: Every 1-2 Years
For most Auckland homes, a soft wash of the exterior every 12 to 24 months keeps mould and algae under control. If your house is in a particularly damp, shaded spot — like backing onto bush or in a valley — you might need it annually.
Homes near the coast have a double problem: salt spray plus humidity. Salt residue on your cladding attracts moisture, which feeds mould growth. If you are within a kilometre of the sea, consider annual washing.
Driveway and Paths: Once a Year
Concrete driveways and paths collect oil, tyre marks, and organic growth. An annual pressure wash keeps them looking good and — importantly — removes slip hazards. Mossy paths are one of the most common causes of slips and falls around NZ homes, especially for older family members.
If your driveway is shaded by trees or buildings, you might need it twice a year. Watch for green tinge on the concrete — that is your sign to book a wash.
Deck: Annually, Before Oiling
Timber decks should be cleaned once a year, ideally in spring or early summer so they are ready for the entertaining season. If you oil or stain your deck, cleaning first is essential — oiling over dirt and mould just locks the problem in.
A proper deck clean removes the grey weathered layer and any mould, leaving fresh timber ready to absorb oil. Skip the cleaning and your oil will not penetrate properly, meaning it wears off faster.
Roof: Every 2-3 Years
Mould and lichen on roofs is not just cosmetic — it can damage roof coatings and reduce the lifespan of your roof. A soft wash every 2-3 years keeps growth under control. If you have a painted roof, regular washing also helps maintain your paint warranty.
Never pressure wash a roof — it can force water under flashings and damage the coating. Soft wash only.
Signs You Need to Wash Sooner
Watch for these signs between your regular schedule:
- Green or black streaks appearing on cladding
- A slippery film on paths or decks after rain
- White salt residue on coastal properties
- Mould returning quickly after the last clean
If you spot any of these, do not wait — the longer mould and algae sit on your surfaces, the more damage they do.
The Cost of Not Washing
Skipping regular washing does not just look bad — it costs money. Mould and algae break down paint coatings, meaning you will need to repaint sooner. Moss on paths is a safety hazard. And if you are selling, a dirty exterior knocks thousands off your property value.
Regular washing is one of the cheapest forms of property maintenance there is. A house wash costs a fraction of a repaint, and it extends the life of your paint job by years.
Want to get your property on a washing schedule? Get a free smart estimate on our homepage — we can quote for one-off washes or set up a regular maintenance plan.
Maikolo Tuionetoa
Owner & Lead Painter, Love Waterhouse Painters
Born in Falevai (Waterhouse), Tonga. Painting across NZ since age 18. Pacific Island work ethic, Kiwi standards.