Most granny flat prices you see are for the building. The number that decides whether it happens is the one on top: getting it onto your block, connected and signed off. This page covers both, with our own 2026 rates where we have them and public figures where we don't.
The three buckets
- The home: built on site, or a modular or kit home bought from a maker
- The site: footings, crane and transport, sewer, water, power, stormwater, access and making good
- Paperwork: certifier, reports, planning if needed, plumbing approval, QBCC insurance and the QLeave levy
1. The home
Built on site in Brisbane, public guides put turnkey work at roughly $2,300 to $3,500 per m², so a 1-bed lands around $110,000 to $160,000 and a 60 m² 2-bed around $140,000 to $210,000. Modular and kit prices are usually quoted ex factory, which means footings, crane and connections are not in them. Compare like with like.
2. The site costs people forget
Our own rates, from 2026 supplier quotes and jobs, ex GST. Ranges, because every block is different.
| Item | Typical range (ex GST) | What moves it |
|---|---|---|
| Footings (screw piles, per module) | $4,000 to $11,000 | Soil class, slope, number of piles |
| Delivery, local SEQ (per module) | $1,900 to $4,100 | Distance, width, pilot vehicle |
| Franna crane | $170 to $210 per hour | 2 to 3 hour minimum |
| Big crane lift (150 t) | $9,200 to $13,400 | Reach over the house, road closure |
| Set-out survey | about $1,800 | Required by most certifiers |
| Soil test | about $700 | Decides the footing design |
| Engineering | about $1,600 | Per dwelling |
| Locating services | $1,300 to $1,400 | Where the sewer actually runs |
| Sewer and stormwater connection | $6,000 to $18,000 | Distance to the main, road opening (public guide figure) |
| Driveway, paths, making good | $4,000 to $20,000 | How much the yard gets torn up (public guide figure) |
Add to that power (a sub-main or new meter and maybe a switchboard upgrade), bushfire (BAL) or flood work if your block is mapped, and any retaining on a slope. Outhaus, whose homes we install, publishes its own figure for the whole site side of a modular granny flat: roughly $69,000 to $92,000 on a straightforward SEQ block, and up to $50,000 more on a hard one.
A modular install, all in
Most installs land between $70,000 and $140,000, inc GST, on top of the price of the home. These are installer rates, inc GST, across South East Queensland.
| Bucket | Typical range, inc GST | What moves it |
|---|---|---|
| Certification and approvals | About $25,000 as an owner builder, about $35,000 with a licensed builder | Plans, soil test, engineering, certifier, council lodgement and plumbing approval. The licensed path adds home warranty insurance, the QLeave levy and the builder's margin, so it scales with the value of the home |
| Footings | $800 to $1,200 a pier or stump | Soil, slope and how many piers the engineer calls for. A typical small home sits on 6 to 14 |
| Delivery and crane | $8,000 to $38,000 | The biggest swing: distance, crane size, how far it has to reach, road closures and traffic control |
| Plumbing and drainage | About $16,000 | About $32,000 if the block needs an on-site wastewater system instead of sewer |
| Electrical | $5,000 to $9,000 | Run length from the switchboard, and whether the board or mains need an upgrade |
Outside those ranges, because the map decides them: bushfire and flood reports, a development application or town planner, survey, retaining on a slope, building over a sewer, and any extra inspections.
3. Approvals, insurance and levies
| Item | Cost | Notes |
|---|---|---|
| Building certifier | about $700 to $2,400 ex GST | Our certifier quotes, per granny flat approval |
| Approvals all in (certifier, reports, council) | about $5,500 to $8,200 ex GST | Typical granny flat, no planning application |
| Planning application, if your block needs one | $5,000 to $12,000+ | Town planner and reports; overlay reports can be $5,000 to $25,000 each (public guide figure) |
| Plumbing approval, Brisbane | $1,590 | Council fee 2026-27, application plus inspections |
| QBCC home warranty insurance | about $877 to $1,342 | On $150,000 to $250,000 of work inc GST; jumps above $250,000 |
| QLeave levy | 0.575% of the work ex GST | Only when the work is $150,000 or more |
| Infrastructure charges | Often nil for a true secondary dwelling | Varies by council. Check yours |
What pushes the price up
- A slope or reactive (H2) soil: deeper footings, more stumps
- A long sewer run or a main under the road
- No side access: a bigger crane lifting over the house
- Character, flood or bushfire overlays: reports, and maybe a planning application
- Small lots where the council rules are tight
How to get a real number
Get the home and the site priced separately and itemised. Anyone who gives you one round number before they've looked at the block is guessing. We'll check the block for free, then price the site side in writing.