Across South East Queensland most second homes take three to eight months from the first call to the keys, and the build is the short part: for a modular home about six weeks on site when the checks, the reports and the building approval were done before the contract. The rest is paperwork, and a planning application is the one thing that turns months into a year. Queensland law sets a handful of clocks inside that: the builder gives a signed copy of the contract within five business days, the owner can withdraw within five business days of receiving it, the contract states the start and practical completion dates, a commencement notice follows within 10 business days of starting on site, and a Form 21 final inspection certificate closes it.
The stages, in order
| Stage | Typical time in SEQ | What stretches it |
|---|---|---|
| First call and site check | 1 to 2 weeks | Getting everyone on site at once |
| Block check: zone, overlays, setbacks, sewer, access | 1 to 3 weeks | Overlays, easements, a sewer main in the way |
| Reports: soil, survey, BAL, energy, engineering | 2 to 6 weeks | Engineering waits on soil and survey; bushfire mapping adds a BAL report |
| Building approval and plumbing permit | 2 to 6 weeks once documents are complete | Missing information, a siting referral to council |
| Planning application, only if needed | Months | Information requests, public notification |
| Contract and cooling-off | 1 to 2 weeks | Finance approval |
| Footings | Days to 2 weeks | Rain, rock, reactive clay, slope |
| Factory build | A written date | The maker's order book |
| Crane day | 1 day | Wind, access, road permits |
| Connections, decks, finishing | 2 to 4 weeks | Utility bookings, plumbing inspections |
| Final inspection and certificate | About a week | Outstanding items |
Those times are what installers see on secondary dwelling jobs across the region. The clocks below are the law's.
The clocks Queensland law sets
- Five business days for the builder to give a signed copy of the contract with plans and specifications.
- Five business days of cooling-off from receiving that copy; on a contract of $20,000 or more the clock starts only once the QBCC's consumer building guide has arrived too. Too short to arrange a loan, so finance comes first.
- A start date and a practical completion date in any contract of $20,000 or more, or the way each will be set, and a commencement notice with both within 10 business days of starting on site.
- Ten business days for the builder to claim an extension of time in writing from becoming aware of a delay, approved by the owner in writing.
- Ten business days for the builder to pay the home warranty premium after signing, and before work starts.
- Ten business days for council to decide a standard plumbing permit application.
- Practical completion is the day the work is done to the contract and the law with only minor defects left, recorded on a defects document, and the certifier's Form 21 final inspection certificate signs off a class 1a home.
Where the months go
A job with no planning application and a maker with a slot can run: reports and approval in six to ten weeks, contract and cooling-off in two, footings in one, crane day, and six weeks on site. Three to four months. The same job with an overlay that triggers a planning application adds the council's months in front, and the same job with a lender who pays nothing until the home is on the block adds the time to find the factory stages from elsewhere. Approvals time by council and finance for a factory-built home cover the two.
What to do in which order
- Block check, then the decision on a planning application. Week one.
- Soil test and survey ordered the same week; everything else waits on them.
- Finance lined up while the reports run.
- Selections decided before the contract.
- Contract, cooling-off, then the factory slot and the footings booked together.
- Crane day, connections, final inspection, the Form 21 and the plumbing certificate with the keys. Handover and defects covers the walk-through.
See it for your block
Questions people ask next
How long does a granny flat take from start to finish in Queensland?
Most jobs in South East Queensland run three to eight months from first call to keys. A modular home is about six weeks on site once the reports and the building approval are done; a planning application, where the block needs one, adds months in front.
How long is the cooling-off period on a building contract in Queensland?
Five business days from receiving the signed copy of the contract, which the builder must give within five business days of signing. On a contract of $20,000 or more the clock starts only once the QBCC consumer building guide has also arrived.
What is the Form 21?
The final inspection certificate a building certifier issues for a class 1a home, such as a granny flat, or a class 10 structure. With the plumbing compliance permit it is the paperwork that comes with the keys.
- Queensland Building and Construction Commission Act 1991, schedule 1B (contract copy, cooling-off, dates, commencement notice, extensions of time, practical completion), read October 2026
- QBCC Regulation 2018, section 45 (the $20,000 level 2 amount), read October 2026
- QBCC, cooling-off period, read October 2026
- QBCC, who pays home warranty and when (10 business days), read October 2026
- Queensland Government, building forms (Form 21 final inspection certificate), read October 2026
- Business Queensland, supporting documents for plumbing and drainage permit applications (decision times), read October 2026
- Installer timelines on secondary dwelling jobs across South East Queensland, read 16 October 2026