In this guide:
What is a Dual Occupancy?
A dual occupancy is two dwellings on a single lot of land. Unlike a granny flat (whose floor area is capped by the Housing SEPP and which can't be subdivided), dual occupancy dwellings can be full-sized homes and may be able to be subdivided onto separate titles.
Common configurations include:
- Side-by-side duplex – Two attached dwellings sharing a common wall
- Front and back – One dwelling at front, one at rear of the lot
- Two-storey duplex – One dwelling above the other
- Detached dual occ – Two separate buildings on the lot
Attached vs Detached
The distinction matters because NSW planning rules treat them differently:
Attached dual occupancy
Two dwellings that share a common wall (like a traditional duplex). Generally permitted with consent in R2 Low Density Residential zones and above.
Detached dual occupancy
Two completely separate buildings. The rules vary by council. Some R2 zones permit detached dual occupancies, others don't. Check your LEP's land use table carefully.
💡 Check your LEP
Look for "dual occupancies" or "dual occupancies (attached)" in your LEP's land use table. If it says "dual occupancies (attached)" only, then detached is prohibited in that zone.
Requirements in NSW
Requirements vary by council, but typical controls include:
| Minimum lot size | Set by your council's LEP (varies by council) |
| Minimum frontage | Set by the LEP or DCP, where one applies |
| FSR | From the LEP floor space ratio map, where one applies |
| Height | From the LEP height of buildings map |
| Setbacks | As per DCP (varies) |
| Parking | Set by the DCP |
Your council's Development Control Plan (DCP) will specify exact requirements for setbacks, landscaping, private open space, and design guidelines.
Dual Occupancy vs Granny Flat
| Granny Flat | Dual Occupancy | |
|---|---|---|
| Size limit | Housing SEPP cap (some LEPs allow more) | Limited by FSR only |
| Subdivision | Not permitted | Often possible |
| Min lot size | 450sqm for CDC (Housing SEPP) | Set by the LEP (varies) |
| Approval | Often CDC eligible | Usually needs DA |
Choose a granny flat if: You want a quick, low-cost addition and don't need to subdivide.
Choose dual occupancy if: You want larger dwellings, the ability to sell separately, or maximum return on a development site.
Subdivision Options
One of the key advantages of dual occupancy over granny flats is the potential to subdivide and sell dwellings separately.
Torrens Title Subdivision
Each dwelling gets its own separate lot with defined boundaries. The most straightforward form of ownership. Requires each lot to meet minimum lot size requirements.
Strata Subdivision
Creates individual strata lots within a strata scheme. Common for attached duplexes where the land can't be physically divided. Creates unit entitlements and may involve strata levies.
Community Title
Similar to strata but with different governance structure. Less common for simple dual occupancies.
⚠️ Check minimum lot sizes
To subdivide Torrens title, each resulting lot must meet the minimum lot size in your LEP. For example, if your lot is 600sqm and the minimum is 400sqm, you can't create two compliant lots. Strata subdivision may still be possible.
Getting Approval
Development Application (DA)
Most dual occupancies require a DA to council. This involves:
- Architectural plans
- Site analysis and survey
- BASIX certificate (sustainability assessment)
- Statement of Environmental Effects
- Possibly: traffic report, stormwater plan, arborist report
Timeframe: depends on council, and longer for complex sites
Complying Development Certificate (CDC)
Some dual occupancies may be eligible for CDC under the Low Rise Housing Diversity Code. Requirements are strict:
- Must meet all standards exactly
- Not heritage or conservation area
- Not flood prone (above thresholds)
- Lot must meet minimum size and frontage
CDC is faster but less flexible. Most dual occupancy projects still go through DA.
Key Constraints to Check
Before pursuing a dual occupancy, investigate:
- Lot size and frontage – Must meet minimums
- Zoning – Must permit dual occupancies
- FSR and height – Determines how much you can build
- Easements – May affect building footprint
- Covenants – May restrict multiple dwellings
- Heritage – Adds complexity and constraints
- Flood/bushfire – May affect approval pathway