Retaining walls – approval requirements
A retaining wall is a wall or structure designed and constructed to support soil at a slope steeper than can be naturally supported.
Retaining walls are only required where there is a possibility of land being adversely affected by subsidence. Retaining walls may be required where there are varying levels of land and that land requires supporting at a steeper angle than the land can naturally support itself.
Responsibility for constructing a retaining wall
Owners of retaining walls are required to maintain their walls in a structurally sound manner.
The party who changes the lie of the land either by excavation or building up (fill) is responsible for building a retaining wall. If both neighbours have altered the lie of the land each neighbour will be responsible for the construction and maintenance of the retaining wall to the extent of their own alteration.
A dividing fence is not considered suitable for retaining soil.
Location of retaining walls
Where retaining walls are required, it is preferred that retaining walls are built within the boundaries of the property where the land is proposed to be altered.
It is important to ensure that privacy is maintained when adding fill to a property. In most instances a 1.8m dividing fence on top of a retaining wall is appropriate to prevent overlooking on an adjoining property. Where a retaining wall is not built next to a property boundary and is higher than 0.5m, an additional privacy screen of 1.6m may be required.
Retaining walls may only be built across boundaries where there is written agreement between the affected neighbours. Where the construction of a retaining wall encroaches across a boundary, a form BA20 must be completed and submitted with the building permit application.
If development (planning) approval is required, both land owners will need to sign the development (planning) application forms.
An application for development (planning) approval is generally required for residential properties where:
- Retaining is within the street setback area and has a height of more than 1.0m from natural ground level. This applies to retaining walls associated with fill and excavation
- Retaining wall is within 1.0m – 1.5m of an adjoining property boundary (not being a street boundary) and has a height of more than 0.5m from natural ground level. This applies to retaining walls associated with fill only
- Retaining walls and fill with a height of more than 0.5m from natural ground level that are within 7.5m of a property boundary and no screening is provided to prevent overlooking to an adjoining property
Building permit requirements
A building permit is not required when the retaining wall complies with all of the following:
- The structure retains ground no more than 0.5m in height; and
- The structure isn’t associated with other building work or with the protection of land adjoining the land on which the retaining wall is located; and
- The structure does not affect other land that requires consent.
A retaining wall that does not meet all of the above will require a building permit.
Building permit application forms (certified or uncertified) are available from the Department of Mines, Industry Regulation and Safety website. Certified building permit applications must be accompanied with a Certificate of Design Compliance.
Please refer to the City’s Uncertified Building Application Checklist – Retaining Walls (Class 10b) for information required to be provided with the Building Permit Application (BA2 form).
Fees are in accordance with the Building services fees and charges.
Retaining wall disputes
It is always advisable to attempt to resolve issues or difference in relation to retaining walls by talking with the other party in the first instance. If you can’t reach agreement the guidelines are designed to assist with the process of dealing with issues which relate to retaining wall disputes. By following these steps carefully, resolutions to issues may be more readily resolved between the parties involved.
Please refer to fact sheet below on the Retaining Wall Dispute Guidelines.