Secondary dwellings, often called granny flats, have become one of the most popular additions for homeowners across South East Queensland.
Families are building them for ageing parents, adult children who need their own space or simply as a way to add value to their property. Investors are also looking at dual occupancy projects as a way to generate extra income.
The problem is the rules are not always straightforward. What one council allows, another might restrict. Add terms like “secondary dwelling” and “dual occupancy” into the mix and many property owners feel lost before they even start. This article explains the differences in approvals, costs and size limits, and outlines which councils are making it easier to get granny flats approved right now.
Understanding the Basics
Secondary Dwelling (Granny Flat)
A secondary dwelling is a smaller, self-contained home on the same lot as an existing house. It is usually capped at 80 square metres, although a few councils allow up to 100 square metres. It shares water, power and driveways with the main house and is generally built for family members rather than tenants.
Dual Occupancy
A dual occupancy involves two full sized dwellings on one lot. Each home has its own services, utilities and often its own driveway. Dual occupancy projects are usually designed for investment purposes or for creating a property that could eventually be subdivided.
The distinction is important. Councils generally make it easier to approve a secondary dwelling because it is treated as an extension of a family home. Dual occupancy almost always involves higher costs, longer timeframes and more complex approvals.
Which Councils Are Supporting Granny Flats?
Some South East Queensland councils have been pushing hard to get more granny flats built in response to housing demand.
Brisbane City Council has relaxed its rules in recent years. Secondary dwellings up to 80 square metres are allowed on most residential lots. Many projects do not attract infrastructure charges if the granny flat is for family use.
Logan City Council is the most investor friendly. It is one of the few councils that allows granny flats to be rented to non relatives. This single rule has made Logan the hotspot for investors wanting rental income from a granny flat.
Ipswich and Moreton Bay are supportive but have stricter controls on things like setbacks, parking and overlays. In Ipswich for example, flood overlays can complicate approvals for low lying sites.
Gold Coast City Council allows granny flats but applies more design standards, parking rules and in some areas character provisions.
Somerset and Redlands are generally supportive for family use but they take a more conservative stance on rural and scenic land. Flood and bushfire overlays often come into play for these regions and can add conditions or delays.
Key Differences Between Secondary Dwellings and Dual Occupancy
| Feature | Secondary Dwelling (Granny Flat) | Dual Occupancy |
|---|---|---|
| Size Limit | Usually up to 80m² (some allow 100m²) | No set cap, typically a full house |
| Services | Shares water, power and driveway | Separate services required |
| Rent to Non Relatives? | Only in some councils (for example Logan) | Yes in all councils |
| Approval Pathway | Often code assessable | Often impact assessable |
| Infrastructure Charges | Sometimes waived for family use | Almost always apply |
| Approval Timeframe | Around 6 to 10 weeks | Around 3 to 5 months |
| Best For | Housing relatives, ageing parents, kids | Investors or future subdivision |
How to Navigate the Approvals
Start with a feasibility check. Before drawing up plans, it is critical to confirm what is possible. This means looking at zoning, setbacks, minimum lot sizes and overlays like flood or bushfire.
Understand your council’s stance. Logan might allow a rentable granny flat. Redlands will not. Brisbane is generous on size but still expects compliance with residential character codes in older suburbs.
Get the documentation right. At a minimum you will need a site plan, floor plans and title searches. Many projects also require flood reports, bushfire assessments or engineering drawings.
Know the timeframes and costs. Secondary dwellings that are code assessable usually move quickly. Dual occupancy projects can involve public notification, infrastructure charges and lengthy back and forth with planners.
Work with an experienced planner. Every council interprets the rules differently. A planner who works across South East Queensland councils can anticipate what each council will ask for and prepare a submission that answers those questions upfront.
The Approval Process
- Feasibility and site check – We review your block, zoning and overlays and give you a clear answer on whether a granny flat or dual occupancy is viable.
- Pre lodgement advice – For complicated sites we talk to council early to iron out issues like setbacks, access and overlays.
- Prepare and lodge the development application – A secondary dwelling is often code assessable. A dual occupancy can be impact assessable which means public notification and longer timeframes.
- Council assessment – Code assessable applications can take 4 to 8 weeks. Impact assessable projects often take 8 to 16 weeks or more.
- Decision and conditions – Once council decides, we handle the conditions, work with certifiers and confirm infrastructure charges.
- Building approval and construction – Once planning approval is granted we coordinate building approval so you can begin construction.
How Long Does It All Take?
A simple secondary dwelling might take six to ten weeks to go from application to building approval. A dual occupancy can take three to five months or longer if public notification or state referrals are involved.
Why Work With a Specialist Planner?
The rules for granny flats and dual occupancy are shifting as councils respond to housing pressures. Brisbane and Logan have made it easier. Other councils are following but at their own pace.
A specialist knows how to navigate these moving parts. They can explain why one council waives infrastructure charges while another does not, or why a 100 square metre granny flat is fine in one suburb but not in another.
Our Final Thoughts
Adding a second home to your block can be a smart move but it pays to start with the right advice. Choosing between a secondary dwelling and a dual occupancy is not just about what you want to build, it is about how each option fits with your council’s rules and your budget.
If you are serious about adding a granny flat or considering a dual occupancy, talk to someone who deals with these approvals every day. The right approach will save you months of frustration and thousands in unexpected costs.
