One of the most common questions we get at FPM Building Supplies is: do I need a permit for my retaining wall? The short answer is: it depends on the height. The longer answer involves your local council, the Building Regulations 2018, and in many cases a structural engineer.

Here's what every Victorian homeowner and tradesperson needs to know before they start digging.

The Basic Rule: 1 Metre

Under the Building Regulations 2018 (Victoria), a retaining wall that retains more than 1 metre of soil is classified as a reportable structure and generally requires a building permit. This is measured as the height of soil retained — not the total exposed height of the wall.

So if your wall is 1.2m tall but only retaining 0.9m of soil (because the base is on flat ground), you may be under the threshold. But if you're retaining 1.0m or more, you almost certainly need a permit.

Important: some councils have lower thresholds or additional requirements. Always check with your local council before you start.

When a Permit Is Definitely Required

You will need a building permit if your retaining wall:

• Retains 1 metre or more of soil
• Is within 1.5 metres of a building (including your own house or a neighbour's)
• Is on or near a property boundary
• Is part of a larger earthworks project
• Is in a flood zone, bushfire zone or erosion-prone area
• Involves surcharge loading (e.g. a driveway or structure above the wall)

Even if your wall is under 1 metre, it's worth checking with your council — some municipalities require notification for walls as low as 700mm.

What the Permit Process Involves

Applying for a building permit for a retaining wall typically involves:

1. Engaging a registered building surveyor — they assess your application and issue the permit
2. Structural engineering computations — a certified engineer must calculate post sizes, embedment depths and wall capacity for the specific soil conditions and wall height
3. Site plan — showing the wall location relative to boundaries, structures and drainage
4. Inspection — the surveyor or their inspector will typically inspect the post holes before concrete is poured, and again at completion

FPM Building Supplies provides engineering computations for our concrete sleeper retaining wall systems — download them from our Engineering page. These documents are prepared by a certified structural engineer and are accepted by most Victorian councils as supporting documentation for permit applications.

Walls Near Boundaries

If your retaining wall is on or near a property boundary, you may also need to comply with the Neighbourhood Disputes Resolution Act and notify your neighbour before starting work. For walls that could affect a neighbouring property's drainage or stability, a boundary survey may also be required.

What Happens If You Don't Get a Permit?

Building without a required permit is a serious issue in Victoria. Consequences can include:

• A stop work order from your council
• An order to demolish and remove the wall at your own cost
• Difficulty selling your property — unpermitted structures must be disclosed
• Insurance complications if the wall fails and causes damage

It's simply not worth the risk. The permit process exists to ensure walls are built safely and won't fail.

Exempt Structures

Not all retaining walls require a permit. Under the Building Regulations 2018, a retaining wall may be exempt if it:

• Retains less than 1 metre of soil
• Is not associated with a swimming pool or spa
• Is not in a designated area (flood, bushfire, erosion)
• Does not affect a sewer, drain or easement

Even for exempt walls, it's good practice to build to the same engineering standards — a wall that fails can cause significant property damage regardless of whether a permit was required.

Engineering Certificates for Concrete Sleeper Walls

For concrete sleeper retaining walls using FPM products, our engineering computations cover:

• 75mm concrete sleepers — wall heights up to 1.8m (depending on post length)
• 100mm concrete sleepers — wall heights up to 2.1m (depending on post length)
• Post embedment depths for standard soil conditions
• Maximum wall heights for each post length combination

Download the full engineering computations from our Engineering & Specifications page.

Quick Reference: Do I Need a Permit?

Wall Height (soil retained)	Permit Required?
Under 700mm	Generally no — check with council
700mm–1000mm	Possibly — check with council
Over 1000mm	Yes — building permit required
Near boundary or structure	Yes — regardless of height
Surcharge loading above wall	Yes — regardless of height

Get the Right Materials

FPM Building Supplies stocks everything you need for a compliant, engineered concrete sleeper retaining wall — 50 MPa sleepers, galvanised steel posts, drainage aggregate, geofabric and ag pipe. Our team can advise on the right post lengths and sleeper thickness for your wall height.

Call us on 0431 235 919 or visit our Epping warehouse at 32 Fullarton Drive.