Can the existing ground level be changed to help achieve compliant building heights?
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
Short Answer
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.
Detailed Explanation
Advisory Note 09 – Building Heights, Storeys and Basements states that building height is the vertical distance between Datum Ground Level and the highest point of the building, and that DGL is the base for calculating building height and floor levels.
The more detailed Surveyor-General Guideline No. 3 – Estate Development Plans & Datum Ground Level Surveys, Part 4 defines DGL as the surface ground level determined by a field survey certified by a registered surveyor at:
- Operational Acceptance of the subdivision; or
- if that is unavailable and no new earthworks have occurred, the date of grant of the first lease.
Where neither can be established, DGL is the best estimate of the surface ground level, considering the levels of the immediate surrounding area and certified by a registered surveyor.
Therefore, earthworks, filling or landscaping cannot simply be used to artificially raise the measurement point to achieve a compliant building height. The proposal must be assessed against the established DGL.
No minimum block size does not remove the need for planning assessment.
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