Are there minimum dwelling sizes?
There isn't a general rule saying every dual-occupancy dwelling must be at least, for example, 80 m² or 100 m².
You can therefore have one dwelling smaller than the other, provided both dwellings still achieve the applicable requirements for things such as private open space, parking, solar access, amenity and building design.
There is an important exception to keep in mind: specific size controls can apply for particular purposes. For example, ACT planning requirements have included a 120 m² maximum (excluding garage) for one dwelling in certain RZ1 dual-occupancy unit-title arrangements.
Reference: Planning (Residential Zones) Technical Specifications 2026 (NI2026–303) – Planning (Residential Zones) Technical Specifications 2026 | PDF
Short Answer
There is generally no prescribed minimum floor area for each dwelling in an ACT dual occupancy. However, there can be specific dwelling-size limits or requirements depending on the zone, subdivision/unit-titling proposal and development circumstances.
Detailed Explanation
The ACT residential planning framework does not impose a universal minimum gross floor area for each dual-occupancy dwelling. Dwelling size instead results from compliance with the relevant Residential Zones Policy, Assessment Outcomes, Technical Specifications and applicable Design Guide.
Separate size provisions may apply depending on the proposal, particularly for RZ1 dual occupancy subdivision/unit titling, so those requirements must be checked independently.
No minimum block size does not remove the need for planning assessment.
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