What Does Dual Key Mean? Dual Key vs Dual Occupancy vs Duplex vs Granny Flat in Queensland
By Tim AllenBuyer’s Agent and Director, IPS Buyer’s Agents
What does dual key mean? A dual key property is one dwelling divided into two separate, self-contained homes, each typically with its own kitchen and bathroom, often behind a shared entry with two lockable doors, and sold on one title.[1] You can live in one side and rent out the other, or rent out both. But “dual key” isn’t a planning term: Queensland’s Planning Regulation never uses it.[2] To council, each self-contained half is a dwelling, so a dual key home is approved either as a house with a secondary dwelling (a granny flat) or as a dual occupancy (a duplex).[2][3] That label decides who can live there, whether the halves can be sold separately and what approval the home needed.
Key takeaways
- Dual key is a selling term. Each self-contained half is a dwelling, so council approves the home as a house with a secondary dwelling or as a dual occupancy.[2]
- A granny flat must be subordinate to the main house and can’t be titled separately. Since 26 September 2022 it can be rented to anyone.[3][4]
- A dual occupancy, Brisbane’s planning term for a duplex, is two dwellings that can be the same size, and it can be strata titled.[5][4]
- Councils differ: Moreton Bay caps most granny flats at 45 or 55 m², Ipswich allows up to 120 m² without planning approval, and a new duplex in Brisbane needs a development application.[6][4][5]
- Lenders can be stricter with dual key homes, and a home policy may not cover a granny flat you rent out, so check both before you sign.[1][7]
Dual key in plain words
Canstar describes a dual key apartment as a single dwelling divided into two self-contained ones, each typically with a bedroom, bathroom, kitchen and living space, often reached through a shared foyer with two lockable doors. Dual key houses work the same way, but may be laid out as a larger main dwelling beside a smaller one.[1] The catch is the single title: the property must be sold as one, and many are designed mainly for investors, which can shrink the pool of buyers when you sell.[1]
Under the Planning Regulation, a dwelling is all or part of a building that can be used as a self-contained residence, with food preparation facilities, a bath or shower, a toilet, a wash basin and laundry facilities.[2] Each half of a dual key home meets that test, so the planning question is never “is it dual key?” but “is it a house plus a secondary dwelling, or two dwellings?” A dual key apartment is still one lot in its building, with one set of body corporate fees,[1] so the body corporate search matters as much as the floor plan.
Dual key vs dual occupancy vs duplex vs granny flat
| Type | What it is |
|---|---|
| Dual key[1] | One dwelling split into two self-contained homes on one title, often with a shared entry. Not a planning term. Sold as one property. |
| Granny flat (secondary dwelling)[2][4] | A dwelling used with, but subordinate to, the house on the same lot, attached or not. Part of a “dwelling house”. Can’t be titled separately. |
| Dual occupancy[2][4] | Two dwellings on one lot, attached or detached, or on two lots that share common property. Neither has to be subordinate. Can be strata titled. |
| Duplex[5][4] | Two attached dwellings. In planning terms, a dual occupancy. |
| Multiple dwelling[8] | Three or more dwellings on a property: a different use again. |
The key line is between a granny flat and a dual occupancy. In the state planning department’s words, a secondary dwelling is used with, and is subordinate to, another dwelling on the same lot, is generally smaller and can’t be developed on its own, while a dual occupancy is two dwellings of the same or similar size, on one lot or on two lots that share common property such as a driveway.[3] So if a “granny flat” is as big as the house, ask how it was approved. Titles follow the label: a duplex on two titles is two properties, each with its own rates,[1] while a granny flat can’t be titled apart from the house.[4]
On 26 September 2022, an amendment to the Planning Regulation removed the restrictions on who can live in a secondary dwelling across Queensland. A granny flat can now be rented to anyone, related to the main household or not, in every council area.[3][9] Three things didn’t change:
- Approval conditions. If the planning approval limits who can live in the flat, the owner must make a change application under the Planning Act 2016 before renting it out.[3]
- Building rules. Every new granny flat needs building approval, and changing an existing one from family use to a rental brings in extra fire and sound transmission requirements under the building code. Ask a building certifier.[3]
- Safety. Before renting it out, the owner must hold all relevant approvals and meet smoke alarm and other health and safety requirements.[9]
A self-contained flat whose tenant has no access to the main house is let on a general tenancy agreement (Form 18a); if the tenant shares the kitchen or other facilities, it may be a rooming accommodation agreement (Form R18). Water can be charged only if the flat is individually metered and water efficient and the agreement says so, and unmetered electricity or gas can be charged only if the agreement sets out how.[9]
Each council sets its own rules within the state framework. The Planning Regulation also lets a council decide, by resolution, that a dual occupancy of two attached dwellings in a residential zone needs no planning approval,[10] so check the current rules for the exact lot.
Brisbane
- A house with a granny flat is a “dwelling house” under City Plan 2014. It needs no planning approval if it is accepted development and meets the Dwelling house code, unless an overlay, such as heritage, requires an application. Every house is a Class 1a building and needs building approval.[11]
- A dual occupancy is code or impact assessable, so you need a development application and planning approval first. It may be code assessable in the Low-medium density, Character (infill housing precinct) and Medium density residential zones; impact assessable applications go out for public notification.[5]
- Council has proposed new granny flat limits, including a size limit relative to the site, but they are still under review.[12]
Moreton Bay
- A granny flat is generally accepted development subject to requirements: meet them and you need only building and plumbing approvals.[6]
- The lot needs at least 600 m² and a 12.5 m frontage in the Suburban neighbourhood and Coastal communities precincts, or 450 m² and 10 m elsewhere. The flat can have up to 45 m² of gross floor area on lots of 450 to 800 m², or 55 m² on larger lots, and must sit within 10 m of the house, share its water and electricity connections, driveway and letterbox, and have one extra parking space.[6]
- A dual occupancy is accepted development subject to requirements in the Next generation neighbourhood precinct on a lot within 800 m walk of a higher-order or district centre or a train station, or with two road frontages and 450 m², or a 15 m frontage and 500 m². In the Suburban neighbourhood and Coastal communities precincts it needs code assessment on lots of 1,000 m² or more; in zones and precincts the table doesn’t list, it is impact assessable.[8]
- The Better Housing Amendment, which started on 30 October 2024, changed the rules for both.[6][8]
Ipswich
- Since Ipswich City Plan 2025 took effect on 1 July 2025, most granny flats and dual occupancies need no planning approval if they meet requirements such as setbacks, height and car parking. Building and plumbing approvals are still needed.[4]
- Without planning approval, a granny flat can have up to 60 m² of gross floor area on lots over 450 to 600 m², 90 m² over 600 to 800 m², and 120 m² over 800 m². A dual occupancy dwelling can have 120 m² and 150 m² on those two larger lot sizes.[4]
- Anyone can live in an Ipswich granny flat, but it can’t be titled separately; a dual occupancy can be strata titled.[4]
For prices and rents, see our Ipswich suburb reports, the Ipswich real estate market update and the Moreton Bay property market guide.
Finance. Lenders can be stricter with investment properties than with owner-occupied homes, which can mean a larger deposit and stricter serviceability requirements, especially for a dual key property.[1] Before you offer, ask your broker how their lenders will value the property, whether they treat it as one dwelling or two, and how much of the second rent they count. Four of the five purchases below worked with Moreton Bay Finance Broker on the finance.
Insurance. Moneysmart warns that a granny flat might usually be covered by a home policy but may not be if you’re renting it out, so check how the insurer defines “home” or “building”.[7]
Tax. If you live in one half and rent out the other, you aren’t entitled to the full main residence exemption from capital gains tax. When you sell, the rented part is subject to CGT, based on its share of the floor area and how long it was rented, and you can usually claim deductions, such as home loan interest, for that part.[13] Our guide to the 2026 negative gearing and CGT changes explains how the announced rules treat established homes and new builds. Ask your accountant how both apply.
Gross yield is a year’s rent divided by the price. At our Churchill purchase, rent of $910 a week is $47,320 a year, which on $695,000 is about 6.8%. Our five dual-living purchases, with each success story’s published figures:
- Churchill, Ipswich (October 2024). $695,000 for a 4-bedroom house and 1-bedroom granny flat on 810 m². Rent of $910 a week, a 6.80% gross yield. Churchill dual income story.
- Deception Bay, Moreton Bay (January 2025). $705,000 for a 3-bedroom house on 607 m² in Next Generation Neighbourhood zoning, with a 2-bedroom granny flat built after settlement. Rent of $570 a week for the house and $420 for the flat, $51,480 a year, a 7.3% gross yield. Deception Bay dual income story.
- Kallangur, Moreton Bay (February 2021). $396,000 for a 3-bedroom house on 607 m² that first home buyers renovated before adding a 2-bedroom granny flat. Rent of $600 a week (estimate) for the house and $435 for the tenanted flat, $1,035 a week, a 13.55% gross yield on the purchase price. Kallangur granny flat story.
- Burpengary, Moreton Bay (July 2024). $600,000 for a 3-bedroom house on 800 m², appraised at $545 a week (a 4.72% gross yield), with a planned granny flat estimated to add $340 a week. Burpengary dual income story.
- Silkstone, Ipswich (April 2025). $940,000 for a 3-bedroom-plus-study, 3-bathroom home on 810 m², bought as a retirement home with dual living for a carer, adult children or rental income. Silkstone dual living story.
Read those yields with care: they are gross, before rates, insurance, management and repairs. The Deception Bay and Kallangur yields are worked on the purchase price alone; both granny flats, and Kallangur’s renovation, came after the purchase, so their cost isn’t in those figures. Test your own numbers with our investment property calculator, and see our high-yield investment strategies for SEQ.
- How it was approved. Ask for the planning and building approvals and check they match what you’re buying: a house with a secondary dwelling, or a dual occupancy. A self-contained second dwelling is a dwelling whatever the listing calls it.[2]
- Fire and sound separation. A flat you plan to rent may need extra fire and sound work, so ask a certifier,[3] and have your building and pest inspection look closely at the walls between the dwellings.
- Meters. In Moreton Bay a granny flat shares the house’s water and electricity connections,[6] which shapes what you can bill a tenant for.[9]
- “STCA” promises. A listing that says a duplex or granny flat is possible “STCA” is offering a possibility, not an approval: see what STCA means.
- Title, lender and insurer. One title means selling as one property.[1] Get your lender and insurer to confirm in writing how they treat the property before your finance date.
IPS Buyer’s Agents works only for buyers. We look for properties where the rent, the land and the planning line up, and work with your broker, building and pest inspector and solicitor through to settlement. At Churchill we negotiated $5,000 off after the building and pest inspection, and at Kallangur we supported a first home buyer’s staged plan: live in, renovate, then build the granny flat. See our buyer’s agent services, or our local pages for Moreton Bay and Ipswich.
Dual key is a selling term; the planning label underneath decides what you can do. Before you buy, find out whether the second dwelling is a secondary dwelling or a dual occupancy, what your council allows on the lot, and how your lender, insurer and accountant will treat it.
This article is general information only, current at November 2026. It is not legal, financial or tax advice and does not consider your circumstances. Planning rules change and differ from lot to lot, so check your council’s current requirements and get advice from your solicitor, broker, insurer and accountant before you act.
If you’re weighing up a dual key home, a duplex or a house with room for a granny flat, book a time with Tim Allen to talk it through.
- Canstar — Dual key apartments: what are the pros and cons? (3 July 2026)
- Planning Regulation 2017 (Qld), schedule 24 (dictionary): dual occupancy, dwelling, dwelling house and secondary dwelling (reprint current from 11 September 2026, read 10 November 2026)
- Department of State Development, Infrastructure and Planning — Secondary dwellings providing housing solutions (last updated 21 July 2026)
- Ipswich City Council — Housing in Ipswich: secondary dwellings and dual occupancies under Ipswich City Plan 2025 (read 10 November 2026)
- Brisbane City Council — Dual occupancy: planning and building requirements (read 10 November 2026)
- City of Moreton Bay — MBRC Planning Scheme information sheet: Secondary dwelling (read 10 November 2026)
- ASIC Moneysmart — Choosing home insurance (last updated 2 October 2026)
- City of Moreton Bay — MBRC Planning Scheme information sheet: Dual occupancy (read 10 November 2026)
- Residential Tenancies Authority — Changes to renting granny flats explained (31 October 2022, last updated 5 April 2023)
- Planning Regulation 2017 (Qld), schedule 6, section 2(3): material change of use for a dual occupancy that a planning scheme cannot make assessable (reprint current from 11 September 2026, read 10 November 2026)
- Brisbane City Council — New house: approvals and requirements (read 10 November 2026)
- Brisbane City Council — Major amendment package L: proposed City Plan changes for small-scale housing, including secondary dwellings (read 10 November 2026)
- Australian Taxation Office — Using your home for rental or business (last updated 22 June 2026)
Can you sell half of a dual key property?
No. A dual key property has one title, so it must be sold as a single property, and turning it back into one home later can be costly. To sell one side at a time you need two titles: a dual occupancy can be strata titled, but a granny flat can’t be titled separately from the house.
Can I rent my granny flat to anyone in Queensland?
Yes. Since 26 September 2022, a secondary dwelling can be rented to anyone, related to the household or not, in every Queensland council area. If its planning approval limits who can live there, you need a change application first. Renting it out also brings in extra fire and sound requirements under the building code, so ask a building certifier.
Is a duplex the same as a dual occupancy?
In planning terms, yes. Brisbane City Plan 2014 uses dual occupancy as its term for duplex developments, and the Planning Regulation defines a dual occupancy as two dwellings on one lot, attached or detached, or on two lots sharing common property. A duplex is the attached kind. Neither dwelling has to be smaller, and it can be strata titled.
Do I need council approval to build a granny flat?
You always need building approval. Planning approval depends on the council and the lot. In Moreton Bay, a granny flat that meets the scheme’s requirements, including a 45 or 55 square metre size cap, needs only building and plumbing approvals. Ipswich removed planning approval in most cases from 1 July 2025. In Brisbane, it depends on the Dwelling house code and any overlays.
Is a dual key property harder to finance?
It can be. Lenders can be stricter with investment properties, which can mean a larger deposit and stricter serviceability requirements, especially for a dual key property. Many dual key homes are designed mainly for investors, so there may be fewer buyers when you sell. Ask your broker how their lenders value the property and count the second rent.
Does renting out part of my home affect capital gains tax?
Yes. If you live in one half of a dual key home and rent out the other, you aren’t entitled to the full main residence exemption. When you sell, the rented part is subject to capital gains tax, based on its share of the floor area and how long it was rented, and you can usually claim deductions for that part. Ask your accountant.