Answer:
No — Expandify homes are designed as Class 1a single dwellings or secondary dwellings under the NCC. They are not suitable for use as dual occupancy or duplex buildings.

Key distinctions:

• Dual occupancy involves two separate primary dwellings on one lot — this requires separate engineering, DA processes, and Class 2 or Class 1 dual classification
• Duplex approvals typically apply only to R3 or R4 residential zones, which require larger lot sizes and different fire rating standards

Expandify homes can be installed as:

• A secondary dwelling behind an existing house
• A standalone Class 1a dwelling on vacant rural or urban land

If you’re seeking dual occupancy development, we recommend speaking to a town planner about alternative housing models.