Can the existing ground level be changed to help achieve compliant building heights?
No. The existing ground level cannot simply be changed to make a proposed building comply with the maximum building height. Building height in the ACT is measured from Datum Ground Level (DGL) to the highest point of the building, rather than from a newly raised finished ground level.
No. Adding fill or changing the ground around the building does not give you extra allowable building height. The building height is measured from the established Datum Ground Level, which provides the baseline for height calculations.
DGL is established by a registered surveyor based on the ground level at the relevant historical point, such as subdivision or the first lease. If that information is unavailable, the surveyor determines the best estimate of the original surface level using the surrounding ground levels and available information.
Example: If you add 500 mm of fill around a proposed house, you cannot simply measure the building from the top of that new fill to gain an additional 500 mm of allowable height.
Reference: ACT Planning, Advisory Note 09 – Building Heights, Storeys and Basements - Building heights, storeys and basements
Link on the answer: https://www.planning.act.gov.au/__data/assets/pdf_file/0012/2323002/an09-working-out-building-heights-storeys-basements.pdf
Where this question is kept
| Dual Occupancy Q&A | #489 | agrees | 26/08/2026 |