Dual Occupancy / Auxiliary dwelling is the correct terminology for this type of building. Also known as dual key, dual dwelling and various other names. They are two homes in one. They are not approved to be strata titled like a Duplex, which means that both dwellings or units are on one title with one set of rates, therefore there are no body corporate fees.
If Town Planning rules were to change in the future and these dwellings were allowed on smaller block sizes, there would be no building changes required to allow the two units to be strata titled, providing that it complied with the new minimum block size at that time.
Both self-contained units are usually under the same roof, so from the street the building looks like a normal house. If attached and under the same roof the units are separated by a fire wall which also provides great acoustic benefits.
Details
Typically, a Dual Occupancy/Auxiliary dwelling has 2, 3 or 4 bedrooms on one side (the ‘main dwelling’) which can be any size and configuration and 1 or 2 bedrooms on the other side (the ‘auxiliary unit’). Each unit has its own entrance and full facilities, including a kitchen, bathroom, laundry, bedrooms, living areas and car accommodation. The size of the auxiliary unit and the number of bedrooms allowed, varies from Council to Council in Queensland. Different rules also apply in other states. For example, NSW has overarching State legislation allowing dual occupancy/auxiliary dwellings in all Local Government Areas however each LGA can have their own variations to the requirements. Dual occupancy/ auxiliary dwellings can’t be built in Victoria. They are allowed in WA and other States vary.