Most people asking for pressure cleaning want a driveway, a path or a pool surround done. Those are genuinely pressure jobs. The problem is when the same machine gets pointed at the rest of the house.
On the Northern Beaches that matters more than usual, because several of the surfaces that must never see high pressure are very common here.
What takes pressure
- Concrete driveways and paths — the core of the work. See pressure washing a driveway.
- Brick and concrete pavers — at moderate pressure, angled across the joints so the jointing sand stays in. Detail here.
- Exposed aggregate, carefully — too much pressure strips the cement paste and loosens the stones.
- Retaining walls and steps in sound concrete or hard stone.
- Tennis courts and hardstand.
What does not
This is the longer list, and on the Beaches it is the list that gets ignored.
Roofs. Any roof, tile or metal. It strips the tile coating, drives water under the laps and onto the sarking, and breaks tiles. The full argument, and for moss specifically, moss on roof tiles.
Fibro. A great deal of mid-century Northern Beaches housing is fibro, and pre-late-1980s sheeting should be assumed to contain asbestos. Pressure washing it erodes the cement matrix and aerosolises the fibres. This is the most serious item on the list. Read this, and for fences, this.
Render and texture coat. Soft wash. High pressure damages the paint film and drives water into the substrate — worse if there is any cracking, which should be checked first: cracked render.
Weatherboard and timber cladding. Raises the grain permanently and forces water behind the boards. Here.
Sandstone. Common in older retaining walls and paving across the area. Pressure erodes the surface irreversibly — here.
Timber decks. Here. And composite decking has strict manufacturer limits — here.
Chalked Colorbond — fences, garage doors, roofing. Here.
Weep holes and subfloor vents, which on a bushland block are the only thing keeping the subfloor dry. Here.
Anything electrical — meter boxes, garden lighting, pool equipment, air conditioning. The pre-start check.
Local conditions that change the job
Salt in the surface. On a coastal driveway, salt in the concrete contributes to surface scaling. Washing it out helps; sealing afterwards helps more — see driveway sealer. A penetrating silane-siloxane is the right choice here, not an acrylic film.
Sand everywhere. It gets into joints, tracks and drains, and it abrades surfaces as it moves underfoot and under tyres.
Slip risk. Shaded paths and pool surrounds grow algae quickly in this humidity, and a mossy path is genuinely dangerous. Killing the growth is what restores grip — see removing moss from pavers and slip resistance and who is liable.
Stormwater. A great deal of Northern Beaches stormwater discharges to lagoons, creeks and the ocean with no treatment. Runoff management is not paperwork here — the rules.
Rainwater tanks, on the bushland and acreage blocks — disconnected before work starts.
Water restrictions. Worth knowing what applies before anyone turns a hose on — how much water pressure cleaning uses.
The practical test
If a contractor quotes to pressure wash your roof, your render or your fibro, that tells you what you need to know about the rest of the quote.
A proper job uses pressure where pressure belongs and chemistry everywhere else — which is most of the house. The distinction is set out in house washing vs pressure washing.
For the regional picture see the Northern Beaches exterior cleaning guide, and for a quote, pressure washing on the Northern Beaches.
