House washing: should you DIY or hire a pro in Sydney?
For a ground-floor rinse of cobwebs and dirt you can reach, DIY is fine. For the actual wash — render, cladding, anything above head height — hire a pro. A hire-shop pressure washer forces water behind cladding and etches render; James Hardie specifies low pressure and a soft brush, not high pressure. Schmick soft-washes from $300.
The machine that does the damage
Most DIY house washes start with a pressure washer hired from the local shop for a Saturday. It looks like the right idea — grime blasts off, the wall goes bright, the driveway fills with grey runoff. The problem is what you cannot see. Held close to render, the lance etches the surface and leaves it chalky. Aimed at the seams of cladding, it forces water straight behind the boards, into the cavity where it has nowhere to drain. The dirt comes back in a season; the water sitting behind the wall does not.
Render, weatherboard and fibre-cement are built to shed weather from the outside, not to take a jet from six inches away. Once water is behind the cladding it sits against the frame and the insulation, and the first sign is usually a stain or a soft patch months later — long after the hire washer went back to the shop. The wash that was meant to save a few hundred dollars becomes the reason for a repair bill that dwarfs it. That is the trap of the loud tool: the result you want is temporary, the damage is not.
The manufacturer already wrote the method down
You do not have to trust a cleaning company on this — trust the company that made the wall. James Hardie, whose fibre-cement cladding sits on a large share of Sydney homes, spells the method out in its own maintenance bulletin: gentle washing with low pressure and a soft brush, not high pressure. That is the maker of the surface telling you, in writing, that the hire-shop lance is the wrong tool for the job. When the manufacturer and the Saturday instinct disagree, follow the manufacturer. They designed the finish you are trying to keep.
Soft washing is the method that respects that instruction, and it is the professional one. Instead of force it uses the right cleaning solution and dwell time — the minutes the solution spends dissolving the mould, salt film and grime — then a low-pressure rinse carries it off. Chemistry does the work the pressure was never meant to do. It is slower and far less dramatic to watch, which is exactly why it is a trade and not a chore: the skill sits in reading what the wall is made of and mixing for it, not in the noise of a motor.
Height is the risk you are underpricing
The other half of a house wash happens above your head, and that is where DIY stops being about finish and starts being about safety. A wall does not clean itself from the ground. The upper storey, the gable, the eaves line — all of it means a ladder on uneven ground, one hand on a wet lance, and the recoil of a pressure washer trying to shove you off the rungs. Falls from ladders put Australians in hospital every year, and household cleaning jobs are one of the most common reasons the ladder comes out in the first place.
A single-storey rinse you can reach is one thing. A two-storey wall is another job entirely — it needs proper access, the right reach gear, and someone who does it every week rather than once a year. That is also why the price steps up with height instead of staying flat: a two-storey wash is more wall, more setup and more risk, and it is priced for the access, not just the area. The couple of hundred dollars you save by doing it yourself is not worth an afternoon in emergency.
When a ground-floor rinse is fine, and when it is not
Here is the honest line, because pretending every job needs a professional is its own kind of sales pitch. A garden hose over the ground-floor brick, a soft broom on the cobwebs under the eaves you can reach, a rinse of the front porch and the bin area — that is fine to do yourself, and no one needs to book a wash for it. Cleaning has limits too: soft washing lifts mould, salt and organic grime, but it will not undo render that is already etched or paint that has chalked after years of hard sun. Candour about that is the point.
It stops being a DIY job the moment three things appear: height, pressure, or a surface that scars. Anything above the ground floor, anything that tempts you toward a hired pressure washer, and any render, fibre-cement, Colorbond or heritage surface that a stiff jet would mark — that is where both the method and the ladder need to be someone else's problem. The simple test still holds: if the wall would show a scratch from a firm brush, it wants soft washing by someone who does it for a living.
What the pro version actually costs
Most people reach for the hire washer on a guess that a professional wash costs far more than it does. A Schmick house soft wash starts at $300, and most single-storey homes land between $420 and $960 depending on wall area — the count of walls, the height, and how much growth is on them. A second storey adds around 40%, for the access and the risk that height brings rather than a round-up. It is a known number before anyone turns up, not a figure invented on your driveway once the gear is already out.
That is the whole point of the instant quote: put in your address and the surfaces, and it returns a firm, bookable price in about sixty seconds — one that holds unless the place turns out materially different from what you described. You can set that against a Saturday of hire fees, sore shoulders and time on a ladder, and decide with the real number in front of you. For most Sydney homes, the wall its own maker recommends washing gently is cheaper to protect than to repair.