How it works
Sixty seconds on the form, no account, no call centre.
We pass it straight to one of the experienced, insured local retaining wall builders who works your suburb.
Free quote, no obligation. You deal with them directly from there.
Perth is a sand city. The Hills is not
Every generic Perth retaining wall page assumes sand. Up here the ground is ironstone and laterite gravel over weathered granite, and the City of Kalamunda has it in writing. Its Local Planning Strategy records that reticulated sewerage is constrained in the Hills because hard granite sits close to the surface and is costly to dig through. When a council says in writing that the rock is too hard to trench, that is your post holes it is talking about.
That is why a quote for a wall in Lesmurdie or Darlington is not a quote for the same wall on the coastal plain. Post holes can hit rock, which changes the method and sometimes the machine. Rock breaking or coring may be needed. And heavy soils and perched water tables, both named as Hills constraints in the Shire of Mundaring's own strategy, mean water sits behind a wall instead of soaking away. Water, not weight, is what kills walls here, which is why drainage behind walls gets its own page.
What a wall costs, and why the Hills reads higher
As a rough 2026 guide, a wall about a metre high runs from around $200 per metre for timber up to $700 or more per metre for stone and engineered block, with concrete sleepers in between. Those are published national guide figures, not a quote, and rock is the reason a Hills price can sit above the Perth average. Our retaining wall cost guide breaks the ranges down by material and covers the rock caveat properly.
Approval in WA: it is 500mm, and it is measured oddly
In WA a retaining wall is exempt from needing a building permit only where it retains no more than 500mm of ground, is not tied to other building work or to holding up the land next door, and is not work of a kind that affects adjoining land. The measurement is the ground the wall retains, not the height of the wall, which catches a lot of people out. All three conditions have to be met, so a wall on or near a boundary needs a permit whatever its height.
Development approval under the local planning scheme can be a separate question again. Four different local governments assess work across this service area, the Shire of Mundaring, the City of Kalamunda, the City of Swan and the City of Armadale, and the local government is the permit authority. Rules and exemptions change, so confirm your wall with yours before you compare quotes. The builders we work with do that as a matter of course.
Septic systems decide where a wall can go
Plenty of the Hills is not on reticulated sewerage. Outside the Kalamunda and Mundaring town centres, most places run their own septic tank and leach drains or a secondary treatment system, sometimes called an ATU. That changes a wall job in a way no generic page allows for: where the tank, the leach drains and the irrigation area sit decides where a machine can get in, where spoil can be stacked and where the wall's drainage can legally discharge. Your local government holds the records and can tell you which system your address has.
How this service works
Perth Hills Retaining Walls is a local referral service, not a construction company. You tell us what you need, we pass it to one of the experienced, insured local retaining wall builders who works your suburb, and they call you back with a free, no obligation quote. If your wall is already moving, go straight to wall leaning or collapsed.