Do retaining walls need approval or an engineer?

It depends on the height of the wall, how close it is to a boundary or building, what it holds back (such as a driveway or a house), and your council's rules. Low walls away from boundaries may be exempt, while taller walls, walls near boundaries or walls supporting loads usually need approval and an engineer's design. A failed retaining wall can damage your home and your neighbour's property, so check before you build, even for small walls.

General information only. Requirements vary by state or territory and change over time, so check the current rules for your location.