A retaining wall is a wall that holds back earth and prevents it from sliding or eroding away. When natural ground levels are altered a retaining wall may be required to support buildings or adjoining land where battering is insufficient.
When is a retaining wall required?
A retaining wall may be required to support a structure or boundary, or simply for landscaping or aesthetic purposes. In new estates, retaining walls are often constructed as part of the subdivision process, but in some cases development on individual lots may cause a need for retaining to protect the foundations of a building or to avoid impacting the adjoining land.
In established areas a retaining wall may be required as a result of change or development on a lot. Cutting (lowering) or filling (raising) the ground level adjacent to a boundary may cause the need for a retaining wall to avoid encroaching or adversely affecting adjoining land (including the verge area). Cutting and filling can result not only from earthworks, but also from simple domestic work. Landscaping work, such as clearing or levelling a site can result in a ground level difference at the boundary. Likewise, excessive garden fill against a boundary can raise the ground level against a boundary fence.
Retaining walls are often constructed of concrete panels, reconstituted limestone or masonry blocks. A fence should not be used as a retaining wall unless it is designed to do so (refer to manufacturer’s specifications). Fibrous cement and asbestos “super six” fences are generally not designed to be used for retaining and cutting or filling against a boundary fence may cause the fence to crack or lean
Do I need a permit?
A building permit is required for any retaining wall that retains ground more than 0.5 metre in height. A permit is also required, regardless of height, for any retaining wall that:
- is associated with any other building work (e.g. the construction of a dwelling); or
- will encroach into another lot; or
- will adversely affect adjoining land, or is required to protect adjoining land; or
- will affect a party wall, substantial dividing fence or existing boundary retaining wall.
For information about how to obtain approval for a retaining wall, refer to the Building and Demolition Work section of our website or to the Related Links below.
In addition to the requirement for a building permit, development approval may be required for retaining walls that are more than 0.5 metre in height or less than 1.5 metres form the property boundary. Development approval should be obtained before applying for a building permit. For more information, please contact us.