How much does a granny flat cost in Queensland?
Short answer: there is no reliable single price. Published Queensland figures for a similar two-bedroom granny flat range from about $129,000 to $300,000, because "cost" means different things in different guides. The number that matters is total project cost for your block: the build, the site, the connections, the approvals and a contingency.
Why every cost guide gives a different number
Search for what a granny flat costs in Brisbane and you will find, for example, one guide quoting $129,000 to $193,000 turnkey for a roughly 60 m² two-bedroom and another quoting $180,000 to $280,000 for the same size. Neither is necessarily wrong. The word "cost" is doing at least five different jobs:
- Supply only: the building and nothing else.
- Base build: on a flat, easy, accessible block.
- Turnkey: a marketing word with no legal definition. Ask exactly what is and isn't included.
- All-in: build plus site works, services and approvals.
- Total project cost: everything, including the things nobody publishes because they depend on your council and your block.
Three more things drive the spread: whether GST is included, who published the figure (many cost guides are run by businesses that generate builder leads, and a lower number generates more enquiries), and your block. Almost every published guide describes the easy block.
The Queensland cost checklist
Use this as a worksheet. A line you have not priced is not zero: it is unknown. Put a range on it.
| Cost line | Usually in the builder's quote? | Queensland note |
|---|---|---|
| The building itself | Yes | Check what "turnkey" includes: flooring, window coverings, appliances, air-conditioning. |
| Contour and detail survey | Often not | Needed for design on sloping lots. |
| Soil test and structural engineering | Sometimes | Reactive soils and slopes change the footing design. |
| Energy and building design documents | Sometimes | Required for building approval. |
| Building certifier fees and inspections | Sometimes | Private certifiers are normally engaged through the builder; confirm who engages and pays. |
| Planning application fee | No | Only if your project is not accepted development. |
| Council infrastructure charges | No | Depends on council and approval type. State-capped. See below. |
| Site clearing, excavation, retaining walls | Provisional sum | Rock and unexpected ground conditions are a classic overrun. Ask who carries the risk. |
| Bushfire (BAL) or flood-related construction | No | Overlays can add real money to the build. |
| Sewer, water and stormwater connections | Sometimes | Water authority approval and connection fees are separate. Build-over-asset conditions can add engineering. |
| Electrical mains or switchboard upgrade | Often not | Ask your electrician early. |
| Driveway, crossover, parking | No | Council requirements vary. |
| Landscaping, fencing, privacy screening | No | Easy to forget. |
| Insurance and home warranty | Check | Residential work over $3,300 needs home warranty insurance through the QBCC scheme. Ask for the notice of cover. |
| Contingency | No | Plan 12 to 15 per cent. If it only works at the bottom of every range, it doesn't work. |
Council infrastructure charges
These are the line that surprises people. Queensland councils can levy infrastructure charges to help pay for roads, water and sewer, but the state caps what they can charge. A 2023 Queensland Government answer to Parliament put the cap at $22,200 for a dwelling with two or fewer bedrooms and $31,080 for three or more, and noted councils can levy a charge for both the primary and secondary dwelling as separate dwellings. The caps are indexed annually, so check the current figure.
What a council actually charges varies:
- Fraser Coast Regional Council lists nil infrastructure charges for a secondary dwelling.
- Livingstone Shire says a secondary dwelling over its 80 m² threshold is subject to infrastructure charges.
- Redland levies a charge on secondary dwellings that don't comply with the gross floor area probable solution in its Amenity and Aesthetics Guideline.
- Logan's infrastructure charges resolution applies the same charges to secondary dwellings as to auxiliary units.
Ask your council: "Is an infrastructure charge payable for this project, roughly how much, and when does it fall due?" Also ask whether your water authority charges separately for water and sewer infrastructure.
How to get a real number
- Decide the structure first (see granny flats in Queensland), because a fixed secondary dwelling, a modular build and a tiny home on wheels have different cost and approval paths.
- Do the free checks (zone, overlays, title, sewer) so builders can quote the real site.
- Get three itemised, fixed-price quotes from QBCC-licensed builders against the same written scope. See choosing a builder.
- Add your own lines from the checklist above that no builder prices: survey, charges, connections, landscaping.
- Add contingency and decide whether the project still works at the top of the range.
Our free 12-question check shows which of these unknowns apply to your block.
Sources
- Queensland Parliament, answer to Question on Notice 1574 of 2023 (maximum adopted infrastructure charges for dwellings).
- Fraser Coast Regional Council, Dual occupancy or secondary dwelling; Livingstone Shire Council, Secondary dwellings information sheet.
- Redland City Council, Changes to Amenity and Aesthetics Policy and Guideline.
- Logan City Council, Summary of changes to the Logan charges resolution.
- QBCC, Key information for QBCC licensees and homeowners (May 2025).
- Published Brisbane price guides compared: What's the Damage and Roomi. Shown only to illustrate the spread; neither is a quote.
General information only, not financial, legal or building advice. Figures change: confirm with your council and obtain written quotes.
Frequently asked questions
How much does a granny flat cost in Queensland?
Published Queensland guides disagree widely. For a roughly 60 m² two-bedroom granny flat in Brisbane, guides quote anything from about $129,000 to $300,000. The gap comes from what the figure includes (build only, or site works, connections and approvals too), who published it, and the block. The only useful number is a fixed-price, itemised quote for your block.
What costs are usually not in a builder's quote?
Common extras include survey, soil test and engineering, certifier fees, planning fees where an application is needed, site works such as excavation and retaining, sewer and stormwater connections, electrical upgrades, council infrastructure charges, landscaping, fencing and a contingency. Check the exclusions list line by line.
Do Queensland councils charge infrastructure charges on granny flats?
Some do, depending on the council and on whether the project needs a development approval. The state caps what councils can charge. A 2023 Queensland Government answer put the cap at $22,200 for a dwelling with two or fewer bedrooms and $31,080 for three or more, and the caps are indexed each year. Some councils, such as Fraser Coast, list a nil charge for a secondary dwelling, while others, such as Redland and Livingstone, charge when a secondary dwelling exceeds their size threshold. Ask your council.
How much deposit can a Queensland builder ask for?
According to the QBCC's guidance for licensees and homeowners, the maximum deposit is 10% for a contract under $20,000 and 5% for a contract of $20,000 and above.
Is a cheaper, smaller granny flat always better value?
Not necessarily. A small dwelling has the same kitchen, bathroom, hot water system, switchboard and approval process as a larger one, so those costs are fixed. The cost per square metre rises as the building shrinks, which means shrinking a design saves less than the arithmetic suggests.
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