Updated October 2026
Midvale is a coastal plain suburb at the foot of the scarp, and it is flat. It also sits near where the Shire of Mundaring and the City of Swan meet, which is worth sorting out before you lodge anything. We connect you with builders who cover the 6056 area.
Common wall situations in Midvale
With no slope to retain, the work is garden terracing, raised beds, driveway and crossover edges, pool surrounds, and levelling a yard with a fall across it. Older housing stock also means replacement of timber walls that rotted at soil level years ago.
These are low walls doing a landscaping job, which puts interlocking block, reconstituted limestone and timber ahead of engineered systems, and keeps the approval question simple in most cases.
Drainage still matters on flat ground
A flat block does not mean water is not a problem. A low wall still needs ag-pipe at its base, free draining gravel rather than the spoil that came out of the hole, geotextile fabric so the drain cannot silt up, and somewhere lawful for the water to go. Walls that fail on the plain usually fail because the drainage was left out to win the price. Our retaining wall drainage page covers what to look for.
What a wall costs in Midvale
Guide pricing only, from published Australian cost guides: roughly $200 per metre at the timber end up to $700 or more per metre for stone and engineered block, for a wall about a metre high. Low garden walls on a level block with good access sit at the bottom end. The retaining wall cost guide breaks it down by material.
Approval, and who to ask in Midvale
The WA permit line is 500mm, and it is measured as the ground the wall retains rather than the height of the wall itself. The exemption also requires that the wall is not associated with other building work or with holding up the land next door, and is not work of a kind affecting adjoining land. Fail any one of those and a building permit is needed at any height, which is why boundary walls almost always need one. Development approval can be a separate question. the Shire of Mundaring and the City of Swan is the permit authority here, so check your wall with them first.
Who is allowed to build it is a statutory question in WA, and it turns on how the work is classified under the building legislation rather than on a figure you can look up and apply yourself. We are not going to settle that on a web page. What is worth doing is simple: ask the builder what registration or licence they hold, check it with Building and Energy, and ask your permit authority what your particular wall requires before you sign anything. Before any digging, your builder should lodge a free Before You Dig Australia (BYDA) enquiry so underground services are located.
Frequently asked questions
Which local government is Midvale in?
Worth confirming. Midvale sits around where the Shire of Mundaring and the City of Swan meet, and the local government is your permit authority, so check which covers your address.
Is Midvale a hills suburb?
No. It is on the Swan Coastal Plain and it is flat. The scarp suburbs above it, Greenmount, Boya and Swan View, are the ones with real fall.
What is the cheapest garden wall?
Treated pine timber is usually cheapest to build, and dry-stacked interlocking block is often the cheapest long-life option at garden height because there is nothing in it to rot.
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