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Secondary Dwelling / Granny Flat
Self-contained second dwelling on a lot with an existing primary dwelling.
A$80,000–250,000 build cost4–12 weeks DA timeline
Typical pathway by state
NSW: CDC under SEPP (Housing) 2021 if all dimensions deemed-to-comply (60m² max GFA; min 12m² rear setback)
VIC: Dependent Person Unit (DPU) — Cl 52.18; Planning Permit usually required for stand-alone
QLD: Secondary Dwelling under planning scheme — Council determines triggers
WA: Ancillary Dwelling under R-Codes — up to 70m² typically
Required documents
- ✓Site survey
- ✓Architectural plans
- ✓BASIX (NSW)
- ✓Stormwater connection
- ✓Neighbour notification (where DA pathway)
Optional / triggered docs
- •BAL Assessment
- •Geotech (where soil unknown)
Typical consultants
Key compliance checks
- ▸Maximum GFA (60m² NSW CDC; varies by state)
- ▸Minimum lot size requirement
- ▸Setback from primary dwelling
- ▸Separate utilities (or not) requirement
- ▸Off-street parking requirement
- ▸Private open space provision
Notes
Granny flats are the highest-volume residential project type in AU. NSW SEPP (Housing) makes CDC accessible. Investor pathway: granny flat as rental income source — must be on the same title.
Recommended pack for this project type
Lite DA Pack A$299