Can you build a granny flat in your Brisbane backyard?

Whether a granny flat can be built on your property is decided before any floor plan is chosen. In most parts of Brisbane and South East Queensland, the answer comes down to a handful of practical questions.

1. Is there a practical place to build?

A large backyard doesn’t automatically mean there’s a suitable building area. What matters is the space that remains after the practical constraints are accounted for:

• Setbacks required from boundaries
• The existing home, sheds and other structures
• Easements and underground services
• Flood, vegetation and other property constraints
• Space for parking and private open space where required

The important question isn’t how large the backyard looks, but how much usable building space remains.

2. Can construction reach the site?

A workable building area still needs a practical construction route. Machinery, materials, concrete and trades all need to reach the backyard:

• Access width and height through gates and fences
• Trees, branches and overhead services
• Road access and delivery conditions
• Space for unloading, storage and machinery

Finding space for the building is only half the assessment — you also need a workable way to build it.

3. What site conditions could change the design or budget?

Some conditions don’t stop a granny flat from being built, but they change the foundations, drainage, service connections or construction method:

• Slope and level changes
• Soil conditions and retaining work
• Stormwater and site drainage
• Distance to sewer, water and power connections

Identifying these early matters, because they’re the difference between a realistic proposal and unexpected costs later.

4. What do council rules say for your area?

Every council sets its own limits on secondary dwellings, and they differ from one area to the next — even between neighbouring suburbs. Rules on size, height, setbacks and approvals are decided by your local authority, not by a floor plan catalogue.

You don’t need to work these out on your own. Part of what a builder does is check what applies to your specific block and tell you plainly where things stand.