Secondary dwellings and granny flats

Front of a small blue cladded home

A secondary dwelling is used together with, but subordinate to, another dwelling. They are also known as a granny flat or family accommodation. They’re usually home to relatives or friends of the people living in the main house.

A secondary dwelling can be attached to another dwelling and is no different from any other Class 1a dwelling or Class 2 sole occupancy unit. They must comply with the minimum requirements of the National Construction Code (NCC).

Building a granny flat on your property 

A granny flat is defined as either a secondary dwelling (forming part of a dwelling house) or dual occupancy. To find out if you can build a secondary dwelling on your property, contact a private building certifier. 

If your secondary dwelling meets all the standard rules set out in the planning scheme, it is usually considered ‘accepted development.’ This means you won’t need planning approval. However, depending on the design of your development, you may need: 

If you can’t meet the requirements of accepted development, you will need town planning approval. To apply for planning approval, submit a development application.

Planning regulations determine the requirements that need to be met, and whether your property is suitable for a secondary dwelling. Typical requirements include:

  • site coverage
  • distance from the side and back property boundaries
  • building height.

Learn more about the secondary dwelling requirements of the planning scheme.

What you can build and how it looks depends on the zone or precinct your property is in. Check your property's zoning information by visiting My property look up.

Building requirements for a secondary dwelling

Sanitary facilities

Secondary dwellings must have:

  • a kitchen sink
  • facilities for the preparation and cooking of food
  • a bath or shower
  • clothes washing facilities, including at least one washtub and space in the same room for a washing machine
  • a toilet
  • a washbasin.

A kitchen sink or washbasin cannot be used as a laundry washtub.

Any detached facilities must be used exclusively by the occupants of the building.

Sound insulation 

Sound insulation reduces the noise transmitted between attached dwellings or units. It functions to improve the amenity and privacy of occupants. 

A secondary dwelling attached to a main house or a Class 10a building, but not part of it, must follow the NCC's sound insulation requirements. This applies even if it has a separating wall. A separating wall is a wall that is shared between adjoining Class 1 buildings. 

Fire safety

To contain or slow the spread of fire, it is important to have adequate fire safety measures in place. The NCC outlines these measures, which include:

  • the distance requirements between an allotment boundary and secondary dwelling, and the secondary dwelling and principal dwelling
  • specific requirements for the construction of separating walls and floors. This is for secondary dwellings that are connected to the principal dwelling or built on top of a garage (known as a Fonzie flat)
  • fire-resistance levels (FRL), which are the grading periods in minutes, for structural adequacy, integrity, and insulation. For example, if the wall of a secondary dwelling is within 900 millimetres of the allotment boundary, it will need to have an FRL of 60/60/60 (60 minutes). 

Smoke alarms

At the start of a new or renewed lease, a property owner must ensure their dwelling or unit meets smoke alarm legislation. 

All homes or units being sold or leased must have hard-wired photoelectric, interconnected smoke alarms. In some cases, non-removable 10-year battery smoke alarms can be installed instead of hard-wired alarms. 

For information on landlords' and renters’ obligations, refer to Queensland Fire and Emergency Services.

How to confirm a secondary dwelling is compliant and council-approved

Before you rent out or move into a secondary dwelling, it’s important to make sure it meets all building and council requirements. You should have a licensed private building certifier inspect the dwelling. The certifier will confirm if it complies with the building assessment provisions. If it is compliant, the certifier will issue a Form 29 (Compliance advice for building work).

As part of this process, property owners or prospective buyers can carry out a building compliance search. The search will confirm if the building is approved to be used as a secondary dwelling. It will also advise if the relevant building approvals have been obtained and finalised. 

Leasing a non-compliant secondary dwelling

You should not rent out your secondary dwelling if it is not compliant with building assessment provisions. Obtaining compliance may trigger the need for building approval. This is provided through a private certifier.

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