Are retaining walls considered when assessing setbacks or building height?
No. A retaining wall is generally assessed separately from the house, so it is not added to the house when measuring the house's setback or height.
For example, if a retaining wall is closer to the side boundary than the house, you would not normally use the retaining wall as the outer edge of the house and say that the house itself breaches its side setback. The house setback is assessed from the relevant part of the building.
The retaining wall still needs to be checked separately because different requirements may apply to the wall depending on its height and where it is located.
Similarly, the height of a retaining wall is not added to the building height simply because the house is located behind or above it.
Reference: ACT Planning Advisory Note 09 – Building Heights, Storeys and Basements – Building heights, storeys and basements
Short Answer
Generally, no. A retaining wall is not treated as part of the building when calculating the building’s setback or building height. It is a separate structure and may have its own applicable siting and approval requirements.
For building height specifically, ACT Planning expressly states that retaining walls are not considered buildings or parts of buildings for building-height calculations.
Detailed Explanation
For building height, the position is particularly clear. Advisory Note 09 – Building Heights, Storeys and Basements, under “What forms part of a building?”, identifies “fences, courtyard walls or retaining walls” as structures that are not considered buildings or parts of buildings and therefore are not included in building-height calculations.
For building setbacks, the relevant residential setback provisions should be applied to the building, while a retaining wall is considered separately as a structure. The Planning (Exempt Development) Regulation 2023, Schedule 1, s 1.50, reinforces this distinction by establishing separate requirements for retaining walls based on their own height and location relative to boundaries and the building line.
Example: A house may be set back 3 m from a side boundary while a retaining wall is only 1 m from that boundary. The retaining wall's position does not automatically reduce the house setback to 1 m. The house setback and the retaining wall are assessed separately against the requirements applicable to each
No minimum block size does not remove the need for planning assessment.
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