If you've been thinking about adding a secondary dwelling to your property — or going a step further with a dual occupancy — there's a lot more to it than most people realise. It's one of the areas I get asked about regularly, and the honest answer is: the opportunity is real, but so is the complexity.
Secondary Dwellings: A Starting Point for Most Blocks
The good news is that a secondary dwelling can be built on almost any residential block in the Brisbane region. Whether you're in Brisbane City, Logan, or Moreton Shire, the option is generally available to you. The size limits, however, vary depending on your council. In Logan, for example, you're typically looking at a maximum of 70m2 habitable area; Brisbane City Council 80m². Acreage properties in some councils allow for larger secondary home
For most homeowners, this is the most straightforward path. It doesn't require a Development Application (DA) in many cases, and the process from concept to construction is considerably more streamlined. It's a practical way to generate rental income, house a family member, or simply add value to your property without the heavier regulatory lift of a full dual occupancy.
Dual Occupancy: Bigger Opportunity, Bigger Process
A true dual occupancy is a different proposition altogether. This is where you build two full-sized homes on one block — and it opens the door to genuine investment returns, particularly if subdivision is the end goal. But it comes with a significantly more involved approval pathway.
For a dual occupancy to proceed, you typically need to be in a medium-density zoning area, and the project will almost certainly require a DA. That means longer timeframes, more stakeholders, and yes — more money spent before a single slab is poured. A good town planner isn't optional here; it's essential. They're the ones who understand the ins and outs of what council will and won't accept, and who can steer the application through what can be a lengthy process.
We've built dual occupancies in areas like Balmoral, and I can tell you firsthand that getting a DA across the line in a medium-density zone requires patience, persistence, and the right team behind you.
The End Game: Subdivision and Torrens Title
For most investors building a dual occupancy, the real prize is subdivision — the ability to split the two dwellings into separate Torrens titles and sell them independently. This is fundamentally different from strata title, where even two houses on a block require a body corporate to be established, adding ongoing complexity and cost.
Torrens title is cleaner. Each property becomes its own lot, capable of being bought and sold independently without the overhead of shared management. But getting there isn't automatic. The buildings need to be constructed first, and the footprints need to be designed with subdivision in mind from day one.
One of the most common issues I see at this stage is services — sewer lines, electrical connections, and stormwater — crossing across each other's future lot boundaries. If that happens, you're either redesigning services or creating easements, both of which add time and cost. It's something that needs to be thought through at the design stage, not discovered later.
Is the Complexity Worth It?
That depends almost entirely on what you paid for the land and what your long-term plan is. The build itself is going to cost anywhere from $3,000 to $5,000 per square metre depending on the specification, and that's before you factor in planning costs, holding costs, and the time it takes to navigate approvals.
If you've owned the land for a while and bought well, the numbers can stack up significantly. If you're buying with dual occupancy and subdivision in mind, you need to model the numbers carefully — because there's a lot involved between the vision and the finished result.
The opportunity is real. It just rewards those who plan well and build with the right people.
