Retaining walls are the designed used to restrain soil for unnatural slopes. They are used to bound soils between two different elevation often in areas where the landscape needs to be shaped severely like hillside farming or roadway overpasses. There are four types of retaining wall gravity wall, piling wall, cantilever wall, anchored wall. Different types of retaining wall are more suitable to different applications.
Australian standards for retaining wall only a wall, or a series of walls, that retains a difference in ground level exceeding one meter requires the approval of Council.
Similarly any embankment exceeding 2 meters in height requires approval by council. This is explained further below. Retaining Walls are Class 10b structures under the BCA. The BCA only sets out a performance requirement
The owner who alters the natural lie of the land is generally responsible for providing a retaining wall or embankment. Retaining walls or embankments should generally be built entirely on the site where they are called for, with only the outside face of the wall on the boundary. However, retaining walls may straddle the property boundary where both neighbours are in agreement.
Retaining walls can be built from a variety of materials and can require the specialist to design, a brick layer or a landscaper, who may or may not have the knowledge and experience needed to build a structural sound retaining wall. For this reason, Australian government state building authorities require retaining wall builders to have special license. In many cases a licensed structural engineer will have to build or oversee construction of your retaining wall or your builder will need to have a specialized license.