You’ve got the space out the back. You’ve seen the modular designs. You can already picture the extra income, the room for family, the home office that isn’t your kitchen table.
But! Will council say yes?
It’s the question that stalls most backyard builds before they start, and the answer is more reassuring than most people expect.
In Queensland, the great majority of suburban blocks can accommodate a secondary dwelling.
The trick isn’t luck. It’s knowing what council looks at before you commit to a design, so you choose a home that fits your block.
This guide walks through every site condition that decides the outcome.
There are six checks that apply to every building.
Work through them and you’ll know with real confidence whether your block qualifies and what design suits it.
“A backyard home is a secondary dwelling. Most of us call it a granny flat. It’s a self-contained home on the same lot as your main house. This guide uses both terms.”
First, the two approvals you need (they’re not the same thing)
Building approval, always required: Every new secondary dwelling in Queensland needs building approval, issued by a licensed building certifier.
It confirms the dwelling meets the National Construction Code performance requirements for structural, damp and waterproofing, fire safety, health and amenity, safe movement and access, energy efficiency and livable housing design and applicable state development codes.
There are no exceptions to this one. Without a building permit, council can enforce showcase notices to request for this approval process to be sought or worse require the dwelling to be removed from site.
Planning approval sometimes required: Whether you also need a development application (DA) from your council depends on whether your building qualifies as accepted development (no DA needed) or assessable development (DA needed) under your local planning scheme.
Many blocks proceed without a full DA because they meet the accepted-development rules. Others trigger a DA because of zoning, overlays, setbacks, lot size, or site cover.
The six site conditions below are what determines which pathway your block falls into, and whether council says yes.
“Since September 2022, Queensland lets you rent a compliant secondary dwelling to anyone, not just family. However, it does not remove the approval requirements above.”
The 6 site conditions council checks on every block
Think of these as the report card for your block.
1. Setbacks: How far from the boundaries can you build the secondary dwelling?
Setbacks are the minimum distances your home must sit from the front, side, and rear boundaries.
They’re set by your council and vary with your zone and block size.
As a typical Brisbane example, blocks over 450m2 will need to achieve the setbacks nominated by the Queensland Development Code (QDC) MP 1.2, for example a typical site may require a 6m setback from the front boundary and 1.5m from side and rear boundaries (based on the home being under 4.5m height).
Setbacks decide where on your block the home can physically sit. Get them confirmed upfront and you pick a design that fits perfectly the first time.
2. Fire-rated distances: Separation from the existing house
When you add a second dwelling, there are fire-separation requirements between the new home and the existing one.
How far apart they sit determines what materials you need.
Closer together can mean fire-rated walls.
When you construct a secondary dwelling, you are required to achieve fire separations from both the existing house and from property boundaries.
When building within 1.8m of a primary dwelling and 0.9m of a boundary fence you will then need to adjust designs to achieve compliance with part 9.2.3 of the ABCB Housing Provisions.
It’s a fire rating compliance that is important to design and achieve the required distances.
Further apart often means standard materials are fine. It’s a safety rule, and it’s easy to design around once you know the distance.
3. What’s happening underground
Every block has a soil classification (under Australian Standard AS 2870) that tells you what foundation your home needs.
Classes run from A (stable, minimal movement — simplest footings) through to P (problem sites needing custom engineering).
Most suburban Brisbane blocks land around Class M or S — moderate and very manageable, often though they can be classified as P site classification due to vegetation.
A soil test gives you the answer and removes all the guesswork.
Infrastructure – Sewer, Stormwater and Water is also located in most sites (excluding rural sites on onsite septic and water tank situations) and dependent on the location of your infrastructure will determine additional distances required to maintain a protection to these services.
For example, if you have a sewer line running across your property, authority consent will need to be obtained prior to building anything over these lines and additionally will require additional structural design to protect the infrastructure from damage. A service locator service helps identify the location of these services on site.
4. Energy rating: Which way your block faces
Every new home must hit a 7-star NatHERS energy rating or achieve rating through a deemed to satisfy reporting of NCC acceptable outcomes, and orientation is a huge factor.
North-facing living areas catch the winter sun and pass comfortably.
West-facing rooms can overheat in summer and may need glazing upgrades to comply.
Knowing your block’s orientation up front means choosing a floor plan that works with the sun, not against it.
5. Wind rating: How exposed your site is?
Every permanent home is engineered for the wind conditions on its specific block (under AS 4055).
A sheltered suburban block surrounded by houses gets a lower rating and standard engineering.
An exposed hilltop or coastal block needs a higher rating and a stronger structure.
It’s not complicated — it just needs to be assessed, and it’s part of what makes a modular home a genuine permanent dwelling.
6. Zoning & overlays: What council allows
Every block has a zoning classification and may carry planning overlays.
Flood (affects floor heights),
Character (affects appearance),
Vegetation (affects where you can build), and
Site cover (how much of the block is already built on).
These tell you what’s permitted and any special conditions.
Most of it is visible on Brisbane City Plan’s interactive mapping tool, and a check takes about ten minutes.
The 2 conditions that only apply to some blocks
These are site-specific. They don’t apply everywhere, but where they do, they matter.
- Bushfire zone (BAL rating). If your block is mapped in a bushfire-prone area, it gets a Bushfire Attack Level rating that affects construction materials and design.
- Transport noise corridors. Blocks near major roads or rail may need acoustic treatment to meet noise standards.
How we make this simple
Before you commit to anything, we run all six checks for you — setbacks, fire-rated distances, soil, energy rating, wind rating, and zoning & overlays — plus BAL and transport noise if they apply to your block.
You get clarity on what your block needs, then you choose a design built to suit it.
Ready to find out what your block needs? Visit our display home at the Geebung showroom, to start the conversation.
Frequently asked questions
1. Do I always need council approval for a granny flat in Brisbane? You always need building approval.
You may or may not need a development application, depending on whether your block meets your council’s accepted-development criteria. The six site conditions above determine which pathway applies.
2.Can I rent out my granny flat in Queensland? Yes. Since September 2022, a compliant secondary dwelling in QLD can be rented to anyone, not just family members.
You still need all the relevant building and development approvals first.
3.How big can a granny flat be in Brisbane? Brisbane City Council typically allows secondary dwellings up to around 80m². Different councils list different requirements on their planning schemes.
Larger may be possible through a development application, depending on zoning. Always confirm your block’s specific planning controls.
4.How long does it take to find out if my block qualifies? A full site assessment is quick —orientation, an overlay check can usually be pulled together in a matter of days, not weeks. Soil and wind testing can be completed after design and designs can be modified to suit your site conditions.
5.Is a modular home a “real” permanent dwelling? Yes. It’s engineered for your block’s wind rating, sits on proper footings suited to your soil class, and meets the same National Construction Code and energy standards as any site-built home.
*Note: This guide summarizes general Queensland planning provisions. Planning rules change and vary by block — always confirm current requirements with your council or a licensed building certifier before committing to a design.
