“Dual living” and “multigenerational home” are marketing words, not planning ones. Underneath them sit four quite different things. The dual occupancy guide covers the planning; this page compares the options from a family's point of view.
What are the four ways to house two generations on one lot?
- A granny flat (secondary dwelling): a smaller second home on the same lot as the main house.
- A dual key home: two self-contained dwellings inside one building, explained on the dual key page.
- An attached dual occupancy (duplex): two full-size homes sharing a wall.
- A detached dual occupancy: two separate full-size homes on one lot, usually one behind the other.
How do they compare?
| Option | Size of the second home | Separate title later? | Privacy |
|---|---|---|---|
| Granny flat | 60 m² under the state rules; in Wollongong the greater of 60 m² or 67% of the main house | No | Good if detached |
| Dual key | Depends on how it is approved | Only if approved as a dual occupancy | Shared building, separate doors |
| Attached dual occupancy | Full size | Possible where the standards are met | Shared wall |
| Detached dual occupancy | Full size | Possible where the standards are met | Best |
What do families ask before choosing?
- Will we ever sell one half? If yes, only a dual occupancy keeps that door open. A lot with a granny flat approved under the Housing SEPP cannot be subdivided.
- How much space does the older generation need? A 60 m² granny flat suits one or two people; a full dual occupancy suits a household.
- How separate should it feel? Separate entries, outdoor spaces and parking matter more to everyday life than the floor area.
- What does the block allow? Zone, lot size, width and slope decide which options are even on the table.
Which design points matter most for two generations?
- Step-free access: a level path from parking to the front door, and a bedroom and bathroom on the entry level, so the home works as mobility changes.
- Sound separation: the wall or floor between two households is where most complaints start; it is cheaper to get right at design stage.
- Separate outdoor space: each household needs somewhere private to sit outside.
- Services: separate meters make sharing costs simple and keep the option to subdivide later.
What does Wollongong allow?
Dual occupancies are permitted with consent in Wollongong's R2 Low Density Residential zone. Near the nominated town centres, the state's low and mid-rise standards can apply; the town centres page lists them. Granny flats follow the Wollongong LEP's size limit above.
For families, the right answer usually comes from walking the block first. If you are planning for two generations, start with a local builder of dual occupancy homes for Illawarra families, and decide on the option before anyone draws a plan.
Sources
Checked on 25 October 2026.
- NSW Planning, Secondary dwellings: the 60 m² floor area limit and the rule that a lot with a secondary dwelling cannot be subdivided.
- NSW Legislation, Wollongong Local Environmental Plan 2009: land use table and clause 5.4 (secondary dwelling size).
- NSW Planning, Low and Mid-Rise Housing Policy: summary of key provisions: dual occupancy permissibility, the non-discretionary standards and subdivision.
General information from a builder, not planning or legal advice. Confirm the controls for your lot with your council, a certifier or a solicitor.