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QLD Development

Secondary dwelling vs. Auxiliary Unit vs. Dual Occupancy

Secondary dwelling? Auxiliary Unit? Dual Occupancy? They all look the same but what are the key differences?

Generally, a ‘secondary dwelling’ or more commonly known as a ‘grannyflat’ is a self-contained unit ancillary to a Dwelling house usually for a member of the household group (e.g. direct blood relatives of the primary dwelling house). A Secondary Dwelling cannot be rented separately to the primary dwelling and should genuinely be used as a ‘grannyflat’.

An Auxiliary Unit is restricted by similar provisions to a Secondary Dwelling but rented separately to the primary Dwelling house. The majority of Local Government Areas in South-East Queensland allow Auxiliary Units without any infrastructure charges but it is always good to check with your Local Council or a town planner. An Auxiliary Unit cannot be strata-titled or sold separately to the primary dwelling.

A Dual Occupancy is a completely separate household to the Dwelling House that is already on the site. It can be rented separately from the primary dwelling house on the same title and also strata-titled and sold off separately to the primary house. Think of a Dual Occupancy as a Multiple Dwelling development but only 2 units instead of 3+. Infrastructure charges are applicable, Council approval is required…etc.

Some general differences between the above uses:

  Secondary Dwelling Auxiliary Unit Dual Occupancy
Crossovers One vehicular crossover One vehicular crossover Two crossovers may be allowable
Cars One additional car park may be required Two additional car parks may be required Two additional car parking bays will be required
Functions No limitation One/Two bedrooms, No more than one kitchen, One living space No limitation
Rentable or sellable? Must be occupied by the same household group as the primary dwelling Can be occupied by a separate household group and independently rented out Can be occupied by a separate household group and independently rented out or sold
Services No separate services are required. Can have separate meters installed if desired. Separate services and meters are required.
Letter Box No separate letterbox is allowed A separate letterbox may be allowed. A separate letterbox is required
Fire separation Fire separation is optional Fire separation is mandatory Fire separation is mandatory
Council rates No extra rates apply for a secondary dwelling Additional rates apply Additional rates apply
Infrastructure charges? No infrastructure charges are applicable Some Council regions require infrastructure charges to be paid. Infrastructure charges are payable.
Rubbish bins No additional bins are required. No additional bins are required. Separate bin storage and services are required.

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This article has been written by Alexander Steffan from Steffan Town Planning.

Author: Alex Steffan

Bachelor of Urban and Environmental Planning – Steffan Town Planning – 10+ years experience as a private consultant town planner.