Are there minimum dwelling sizes?
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.
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
Link on the answer: https://www.legislation.act.gov.au/View/ni/2026-303/current/PDF/2026-303.PDF
Where this question is kept
| Dual Occupancy Q&A | #454 | agrees | 27/08/2026 |