Retaining walls

A retaining wall with green trees along the top.

In Queensland, a retaining wall is a structural barrier designed to hold back soil or rock, preventing erosion and creating usable land on slopes or uneven terrain.  

They are classified as a Class 10b building structure under the Building Code of Australia and may require building approval depending on their height, location, and other factors. 

Building approval for retaining walls

Depending on the height and location of the wall, it may need building approval.

If it's less than one metre high, it requires building approval if:

  • it's within 1.5 metres of a building or another retaining wall
  • there is surcharge loading (driveway, footings, structures) over the zone of influence.

A retaining wall more than one metre high requires building approval. A referral agency application is also required if located within the 6 metres by 6 metres truncation of a corner. 

A wall or fence on top of a retaining wall requires building approval if the total height exceeds 2 metres above the natural ground surface. A referral agency application will also be required. 

If you are unsure if your retaining wall needs approval, contact a private building certifier.

Siting requirements for a new retaining wall 

If the wall exceeds 1 metre above the natural ground surface and is within 1.5 metres of the allotment boundary, Council will need to assess it. 

The whole structure must be within the property boundary. This includes the sub-drainage, spoon drainage on the top or at the base of the wall and footings.

If the retaining wall is on a corner allotment, the wall and other structures must not exceed 1 metre in height within the 6 metres by 6 metres truncation.

Find out more about placing a structure on your property.

Building near stormwater infrastructure

Building work over or near stormwater drains must be assessed.

All applications to build over or next to a Unitywater sewer or water main are to be referred to Unitywater.

Find out more about placing a structure on your property.

Responsibility for the cost and maintenance of a retaining wall

A retaining wall is usually more beneficial to one neighbour and built on one property, so it is not usually a joint responsibility.

However, there are circumstances where a wall may be built on the boundary or across the boundary and be over both properties. The owner of the property that has a retaining wall built on it, whether that be only part of the wall, must maintain the wall or that part.  

If responsibility becomes a civil matter, the Queensland Civil and Administrative Tribunal may be able to assist. Alternatively, seek legal advice. 

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