Last updated October 2026
A house wash is one of the simplest ways to keep a Timaru home looking good and lasting longer. Salt from the coast, dust off the plains and moss and mould on the shady sides all build up on cladding, roofs, paths and fences. Left alone, they shorten the life of paint and make surfaces slippery. This guide covers what a house wash involves, soft washing versus water blasting, moss and mould treatment, and how often to do it.
★View the Best Handyman in Timaru→What a house wash is
A house wash cleans the outside of the house: cladding, soffits, window frames, and often the roof, paths, decks and fences. Most professional house washes use a cleaning solution to kill mould and lift grime, followed by a rinse. The aim is to clean the surface without damaging it.
Soft washing or water blasting?
How it works
- Soft washing
- Low pressure with a cleaning solution that does the work
- Water blasting
- High-pressure water strips dirt off
Best for
- Soft washing
- Painted weatherboards, roofs, soffits, delicate surfaces
- Water blasting
- Concrete paths, driveways, hard decks, some fences
Risk
- Soft washing
- Low, if the right solution is used
- Water blasting
- Can strip paint, force water behind cladding and damage timber
Lasting result
- Soft washing
- Kills mould spores, so it stays clean longer
- Water blasting
- Removes visible growth but spores can return quickly
Many jobs use both: a soft wash on the house and roof, and water blasting on concrete and other hard surfaces. Be wary of anyone who wants to water blast painted weatherboards or a roof at high pressure.
Moss and mould: why they matter
Moss and mould grow fastest on the shaded south side of a house and anywhere that stays damp. In Timaru, that often means the side of the house facing the cold southerlies and anything sitting under trees.
- On roofs, moss holds moisture against the roofing, can lift tiles, and washes into the spouting.
- On cladding, mould stains paint and feeds on it, shortening its life.
- On paths and decks, it turns surfaces slippery, a real fall risk for older people and children.
A moss and mould treatment kills the growth and helps prevent it coming back for a while. It usually takes a few weeks of weather for dead moss to wash off a roof fully.
How often should you wash your house?
Once a year suits most homes. Homes near the coast, under trees or on shady sections may need a wash more often. A good rhythm for many Timaru homes is:
- Spring: house wash and moss treatment, ready for summer
- Autumn: gutter clean, after the leaves have fallen
- Before painting: always wash first, because paint will not stick to a dirty or mouldy surface
Can you do it yourself?
A single-storey house with low-maintenance cladding is a manageable DIY job with a garden sprayer, a house wash product and a hose. Read the product label, protect plants, and rinse well.
Two-storey houses, roofs and anything needing a ladder are a different matter. Working at height is a common cause of serious falls, and a wet roof is especially dangerous.
Things to check before booking
- Does the price include the roof, spouting, soffits and windows, or just the walls?
- Will they soft wash painted surfaces rather than water blast them?
- What product do they use, and how will they protect gardens, pets and the water running off?
- Will they treat moss and lichen on the roof and paths?
- Can they combine the wash with a gutter clean or small repairs while they are set up?
Washing before you paint or sell
If you are planning to repaint, a thorough wash is the first step of the job. A clean exterior also helps a house photograph well and makes a good first impression at open homes. Washing often shows up small problems too, such as rotten weatherboards, loose flashings or failing paint, that are cheaper to fix early.
Timaru conditions that affect your exterior
- Coastal salt. Homes near Caroline Bay, the port and the coast north and south of town collect salt on cladding and window frames, which speeds up corrosion and paint wear.
- Shade and damp. South-facing walls and sections under mature trees stay damp after rain and grow mould fastest.
- Wind-blown dust. Dry nor’westers carry dust off the plains, which sticks to damp or mouldy surfaces.
A regular wash removes all three before they do lasting damage.
Getting your house washed in Timaru
The Busyman is a Timaru property maintenance business run by owner Graeme Hunter, with a small team of builders, plumbers and electricians. Its work includes water blasting, moss and mould proofing, spouting cleaning and painting inside and out, so washing, small repairs and repainting can be handled by one team. You can request a quote through the website or call 0800 287 962.
