Granny Flat vs Dual Living vs Duplex: What Is the Difference in Brisbane?
- May 28
- 6 min read
If you have started looking into building a secondary dwelling or investment property on your Brisbane block, you have probably come across a few similar sounding terms.
Granny flat. Secondary dwelling. Dual living. Dual occupancy. Dual income. Duplex.
They are often used interchangeably, but they are not the same thing. The option you choose can affect your build cost, council approval process, rental income potential and long-term property value.
This article explains the key differences between granny flats, dual living homes and duplexes, with a focus on Brisbane and South East Queensland homeowners.
Option 1: Granny Flat, Also Known as a Secondary Dwelling
A granny flat is a self-contained, subordinate dwelling located on the same lot as the main home.
It usually has its own bedroom, bathroom, kitchen and living area, but it cannot be sold separately from the main house. Both dwellings remain on the same title.
A granny flat can be detached from the main home, such as a separate structure in the backyard, or attached to the existing house.
Typical Size in Brisbane
Dixon Homes granny flat designs range from approximately 41 m² to 97 m².
In Brisbane, the key planning number to remember is 80 m². Brisbane City Council generally allows a secondary dwelling as accepted development if it is no more than 80 m² in gross floor area and located within 20 metres of the main dwelling.
Who Is a Granny Flat Best Suited To?
A granny flat is a strong option for homeowners who want to:
Generate rental income
House family members
Create a flexible space for guests, teenagers or older parents
Add value to an existing block
Avoid the complexity of a larger development
Council Approval in Brisbane
In many cases, a development application is not required if the granny flat is under 80 m² and within 20 metres of the main house.
You will still need building approval from a licensed certifier.
Cost Range
Dixon Homes granny flats in South East Queensland start from $130,900 and range up to approximately $250,000, depending on the design, size and inclusions.
Can It Be Rented Out?
Yes. Since the Queensland Government rule change in 2022, granny flats can be rented to anyone on the open market, not just members of the same household.
Can It Be Sold Separately?
Generally, no. A granny flat usually remains part of the same property as the main home and stays on the same title, meaning it cannot be sold as a separate property unless it is separately titled through an approved subdivision or strata title arrangement.
Typical Rental Income
A 2-bedroom granny flat in Brisbane’s middle ring suburbs may generate approximately $200 to $500 per week, depending on the location, design and rental market conditions.
Option 2: Dual Living or Dual Income Home
A dual living home is a single home designed from the beginning to include two separate living areas.
This usually means a main residence plus an attached secondary area with its own entrance, kitchen, bathroom and living space.
The key difference from a standard granny flat is that dual living is usually integrated into the main home design, rather than being a separate structure in the backyard.
Who Is Dual Living Best Suited To?
Dual living can be a good option for:
Multigenerational families
Parents and adult children living together
Homeowners supporting older relatives
Investors wanting strong rental income from one property
Buyers building a new home and wanting flexibility from the start
Council Approval in Brisbane
Dual living homes may still be assessed as a secondary dwelling if the secondary component is under 80 m² and meets the relevant planning requirements.
More complex layouts may require a development application, so it is important to check your specific design and block before proceeding.
Cost Range
Dixon Homes offers dedicated dual living designs, typically starting from approximately $277,600 for the full home with integrated secondary living.
Can It Be Rented Out?
Yes. Both components may be able to generate rental income, depending on the design, tenancy setup and compliance requirements.
Can It Be Sold Separately?
No. A dual living home generally remains on one title and cannot be sold as two separate properties.
Typical Rental Income
A well designed dual living home in Brisbane may generate combined rental income of approximately $700 to $1,000 or more per week, depending on location, layout and market demand.
Option 3: Duplex or Dual Occupancy
A duplex is different again.
A duplex usually consists of two separate dwellings on the same lot. They may be side by side or positioned front and back. Each dwelling is generally a full-sized home, rather than a main home plus a smaller secondary dwelling.
Depending on the project and approval pathway, a duplex may remain on one title or be subdivided through community title or another subdivision arrangement.
Who Is a Duplex Best Suited To?
A duplex is usually best suited to:
Investors
Developers
Owners of larger blocks
Owners of corner blocks
Buyers who want the option to sell one or both dwellings separately
People comfortable with a more complex approval and build process
Council Approval in Brisbane
A duplex usually requires a development application for dual occupancy.
This means the approval process is generally more complex and time consuming than building a granny flat or a compliant dual living home.
Cost Range
Dixon Homes offers duplex designs, with costs varying significantly based on the layout, site conditions and configuration.
As a general indication, a duplex build is typically $350,000 or more for both dwellings combined.
Can It Be Rented Out?
Yes. A duplex can provide two separate rental incomes, with each dwelling generally functioning like a standalone rental property.
Can It Be Sold Separately?
Yes, if the property is subdivided or titled appropriately.
This is one of the main financial advantages of a duplex, as it can create two individually sellable assets.
Typical Rental Income
A duplex may generate approximately $900 to $1,200 or more per week in combined rental income, depending on the location, dwelling sizes and market condition.
Side-by-Side Comparison
Feature | Granny Flat | Dual Living | Duplex |
Separate title | ✕ No | ✕ No | ✓ Yes, if subdivided or strata titled |
Development application needed in Brisbane | ✕ Usually no | ✕ Usually no, depending on design | ✓ Yes |
Can rent to anyone | ✓ Yes | ✓ Yes | ✓ Yes |
Typical combined rental income | $200-$500/week | $700-$1,000+/week | $900-$1,200+/week |
Dixon Homes cost range | $140k-$300k | $277k-$440k | $350k+ |
Block size required | Standard residential block | Standard to medium block | Larger or corner block |
Suitable for investment | ✓ Excellent | ✓ Excellent | ✓ Strongest development option |
Can sell separately | ✕ No | ✕ No | ✓ Yes, if subdivided or strata titled |
Complexity | Low | Low to medium | High |
Which Option Is Right for You?
The best option depends on your block, budget, approval pathway and long-term goals.
Choose a Granny Flat If
A granny flat is likely to suit you if you already own a standard Brisbane block and want a simple, cost-effective way to create extra space or generate rental income.
It is usually the most straightforward option, with lower build costs, a simpler approval pathway and strong rental income potential.
Dixon Homes has 49 granny flat designs available for South East Queensland, starting from $130,900 with fixed pricing.
Choose Dual Living If
Dual living may be the right choice if you are planning a new build and want to maximise flexibility from the beginning.
It can work well for multigenerational families, investors seeking strong rental yield, or homeowners who want two separate living zones within one integrated home design.
Choose a Duplex If
A duplex may be the better option if you have a larger block, often a corner block, and want the potential to create two separately sellable dwellings.
This option generally offers the greatest long term development potential, but it also comes with a more complex approval process, higher build cost and longer project timeline.
The Bottom Line
For most Brisbane homeowners starting with a standard residential block, a granny flat is often the best starting point.
It offers a lower cost, simpler approval pathway, strong rental income potential and far less complexity than a duplex or subdivision project.
Dual living can be a smart option for new builds, especially where family flexibility or higher rental yield is the goal.
A duplex can provide the strongest development upside, but it is usually best suited to larger blocks, investors or owners who are prepared for a more involved approval process.
Compare your options and find the right design for your Brisbane block.
ALL PRICING IS BASED ON BRISBANE AREA RATES FOR FACADES IN THE DIXON HOMES OPTIONAL FACADES BOOKLET. PRICING IS SUBJECT TO CHANGE WITHOUT NOTICE E&OE 31.10.13 | www.dixonhomes.com
Exclusions unless otherwise specified: the construction contract does not provide for the following and/or similar items and/or their installation and/or any additional works to facilitate installation: Window furnishings; decorative light fittings; letter box; retaining walls; landscaping; fencing; driveways and paths; floor coverings; paving; fireplaces; soft furnishings; vehicles; any siteworks other than specifically stated in site estimate; any items not specified on inclusion lists and/or colour selections and/or plans, and not specifically costed in by the builder.
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