Granny flat approval in Brisbane, explained properly
The rules are more homeowner-friendly than most people think - if your design fits the criteria. Here is how Brisbane City Council treats secondary dwellings, in plain English.
What counts as a "granny flat" in Brisbane?
In planning language, a granny flat is a secondary dwelling: a self-contained home on the same lot as your main house, used in conjunction with it. It can be detached in the backyard, attached to the house, or built under a high-set home. It stays on your title - it is not a subdivision.
The two approvals, and which ones you actually need
1. Planning approval - often not required
Under Brisbane City Council's planning scheme, a secondary dwelling that complies with the relevant requirements is generally accepted development: no development application, no public notification, no planning fees. The commonly applied criteria include:
- A maximum secondary dwelling size - 80 m² gross floor area is the commonly cited limit
- The secondary dwelling is used in conjunction with the main dwelling and typically must be located within a set distance of it
- Normal dwelling house rules still apply: boundary setbacks, site cover and height for your zone
- Only one secondary dwelling per lot, and it cannot be separately titled
Fall outside those criteria - or trip an overlay - and a planning application may be needed. That is slower and costlier, so good designers work hard to stay inside the accepted development box.
2. Building approval - always required
Every granny flat needs building approval against the National Construction Code, normally issued by a private building certifier, plus a soil test and structural engineering. Builders in our network manage this for you as part of the project; certification fees are typically built into the quote.
Overlays: the thing that catches people out
- Traditional building character (pre-1947) overlay. Large parts of Brisbane's older suburbs - including areas of Wynnum, Aspley's older pockets and many inner suburbs - carry character protections. A backyard secondary dwelling is often still achievable, but design and materials may need to respond to the overlay, and additional assessment can apply.
- Flood overlays. Brisbane's creek and river flood mapping can affect floor levels, siting and drainage design. Check your property on council's flood awareness tools early.
- Protected vegetation and easements. Significant trees, sewer easements and stormwater infrastructure all constrain where the flat can sit. A site assessment picks these up before you spend on design.
The September 2022 change: rent to anyone
Historically, Queensland secondary dwellings could only be occupied by members of the same household as the main house. On 26 September 2022, the Queensland Government changed the Planning Regulation so secondary dwellings can be rented to people outside your household. That single change is why granny flats went from "space for mum" to a mainstream Brisbane investment. Body corporate rules, existing development conditions and tenancy laws still apply - see the rental and investment page for the realistic numbers.
How approval works when you build with us
Site assessment
Your matched builder checks zoning, overlays, easements, slope and services on your block - free, before you commit to anything.
Design to comply
The design is shaped to fit the accepted development criteria wherever possible, keeping approval fast and planning fees at zero.
Soil test and engineering
Geotech and structural engineering are commissioned so the certifier has everything needed to approve.
Building approval and build
The private certifier issues building approval, inspects at key stages, and issues the final certificate when the build is complete.