When does a retaining wall need a building permit in Victoria?

Short answer: 1 metre or more, or at any height when the wall is tied to other building work or holding up the neighbour’s ground. Below: what that means, why boundaries and easements matter, and what to send us before the sleepers are ordered. If you already know the wall needs a permit, our retaining wall permits page covers what we need from you and what it costs.

Do I need a permit for a retaining wall under 1 metre?

A retaining wall is building work under the Building Act 1993. Schedule 3 of the Building Regulations 2018 exempts a narrow class of walls from needing a building permit, and the key threshold is 1 m of height. A wall is exempt only when it is less than 1 m high, is not associated with other building work, and is not protecting adjoining property. Miss one condition and the wall needs a permit, whatever it is built from; treated pine, boulders and gabion baskets follow the same rules as concrete and block.

Two things to watch on height. First, the exemption is for walls less than 1 m, so a wall built to exactly 1 m is not exempt. The Regulations give no measuring rule for retaining walls, so expect height to be taken at the highest point, not averaged. Second, terraced walls: two 800 mm walls built close together can act as one wall of a metre or more, and can be assessed that way.

Which retaining walls need a permit at any height?

Height is only half the test. The exemption also falls away when the wall is associated with other building work or protects adjoining property. So a wall of any height needs a permit when it is:

part of, or supporting, other building work: a house footing, shed slab, garage, or a swimming pool or spa;
holding up a neighbour’s land, the most common case on subdivided blocks: that is protection of adjoining property.

Driveways sit between the two. Where the driveway is part of a building job, a new house or garage say, the wall is associated with that work and needs a permit. A low wall under a standalone driveway is less clear-cut under the Regulations, but it still needs an engineer to size it for the vehicle load, so check with us first. A 600 mm wall holding up a garage slab needs a permit; a 600 mm garden bed wall in the middle of the yard generally does not.

Does a retaining wall on the boundary need a permit?

Usually, yes. A wall on or near a boundary raises two questions. One: does it retain the neighbour’s ground? If so, it is protecting adjoining property and sits outside the exemption, whatever its height. Two: if a fence goes on top, the siting provisions measure fence height from natural ground level, so where the wall holds fill, wall and fence are assessed together. On a boundary that total can need a report and consent from council even when the wall alone is modest. Excavating close to a boundary can also bring in protection work under Part 7 of the Building Act.

Easements are a separate trap. Building over an easement needs the report and consent of the authority it is vested in, council or the water corporation, before a permit can issue (regulation 130). Check your title before you fix the wall line; moving the wall half a metre is cheaper than the consent process.

Do I need an engineer for a retaining wall?

In practice, any wall that needs a permit needs a structural engineer’s design. The engineer sizes the footings or piers, specifies the reinforcement, and details the drainage behind the wall: agricultural pipe, free-draining backfill, and where the water goes. Water pressure brings down more walls than weak blocks do.

The design also has to account for surcharge: a fence, driveway or building above the wall adds load a plain gravity wall may not handle. Tell the engineer everything that will sit on or behind the wall.

Retaining walls on sloping estate lots

New estates on sloping ground are where most retaining wall questions come from. The developer cuts and fills to create level house pads, and a wall takes up the difference between your pad and the lot next door. At the low corner these walls often reach a metre or more, they almost always retain someone else’s ground, and the builder’s house permit rarely includes them. Check the engineering plans and the contract early.

What to send us

You do not need a permit to ask whether you need one. Send:

The heights along the wall, or a photo with a tape measure in shot.
A site plan or marked-up aerial photo showing boundaries, house and easements.
What sits above or behind the wall: fence, driveway, pool, neighbour’s yard.
The engineer’s drawings, if you have them.
The property address.

We will tell you for free whether the wall needs a permit. If it does, we quote one fixed fee; what it covers is on the service page. A wall that needed a permit and never got one becomes a problem when the block is sold or the wall starts to move.

Retaining wall regulations in Victoria, in one paragraph

The retaining wall regulations in Victoria come down to three conditions. Under Schedule 3 of the Building Regulations 2018 a wall is exempt from a building permit only when it is less than 1 m high, not associated with other building work, and not protecting adjoining property; fail any one and it needs a permit, issued by a registered building surveyor rather than council. Every permitted wall needs an engineer’s design, a wall over an easement needs the easement authority’s consent, and a wall with a fence on top on a boundary can also need council’s report and consent. The material changes none of that.

Ready to check your wall? See our retaining wall building permits page, or send the details through the quote form and we will come back to you within one business day.

Suppliers and installers: you can link your customers to this page, or send their drawings to us direct — see our page for builders and suppliers.