The Australian Granny Flat Guide 2026: Cost, Design, and Approval
Summary
A granny flat in 2026 is no longer a fibro box for an ageing parent. It is the cheapest legal way to add a second income or a second household to land you already own, and demand has followed the affordability numbers straight up. The build itself runs from roughly $120,000 for a small one-bedroom to north of $250,000 for a finished two or three-bedroom, before site costs. The rules are where people lose money, and they are different in every state. New South Wales runs a fast 60m² approval through a private certifier. Victoria has dropped the planning permit altogether for second homes under 60m² on most lots. Queensland scrapped its family-only rental rule years ago. Tasmania is in the middle of lifting its cap from 60m² to 90m² as we publish this. Get the pathway right and you save months. Get it wrong and you pour a slab that has to come back out. This guide walks the cost, the design choices that drive that cost, and the approval pathway in each of the four states we work in.
Table of Contents
What a granny flat actually is (and what your state calls it)
A few years ago a man rang us wanting a quote to “chuck up a granny flat” for his mother-in-law. By the end of the call he wanted two bedrooms, a study nook, and a rental tenant in it within the year. That is the granny flat market now. The name is a hangover. The thing itself has become the most practical piece of housing most people will ever build.
The formal term is a secondary dwelling, and that matters because the brochure word and the planning word are not the same thing. A secondary dwelling is a self-contained home on the same lot as a main house, with its own kitchen, bathroom, and entrance. It is not a bedroom with a sink. It is not a rumpus room you stuck a bar fridge in. The line between those two is the line between a project that gets approved and one that gets a please-explain from council.
Each state uses its own label, and the labels carry different rules. New South Wales and Queensland say “secondary dwelling.” Victoria now says “small second dwelling.” Tasmania says “secondary residence” or “ancillary dwelling.” They describe the same idea, but the size caps, the approval pathway, and the question of who is allowed to live in it differ at every border. We will take them one at a time. First, the number everyone actually came here for.
What a granny flat costs in 2026
The number in the brochure is not the number you pay. It is the number that gets you to ring the builder. I am not being cynical about builders here; the brochure price is usually the honest base build, and then reality is added back in afterwards. Site costs, the slope of your block, how far the sewer is from the new bathroom, the connection of power and water, the certifier, the soil test. None of that is in the headline figure, and all of it is in the final invoice.
So treat any single number you see online the way you would treat a flight advertised at $49. Technically real. Not what leaves your account.
Across the market in 2026, finished granny flat builds are landing in these ranges. These are build costs, not land, and they assume a reasonably flat and accessible site.
| Configuration | Typical 2026 build range | Notes |
|---|---|---|
| Studio / 1-bedroom (around 35–50m²) | $120,000 – $200,000 | Lower end regional, upper end Sydney metro |
| 2-bedroom (around 50–60m²) | $180,000 – $300,000 | The most common build we draw |
| 3-bedroom (over 60m², where allowed) | $220,000 – $320,000+ | Only legal in some states and zones |
On top of the build, budget for the things people forget. Utility connections for power, water, and sewer commonly run $3,000 to $8,000 on their own, and more if the existing services are on the wrong side of the house. Approval costs are separate again, and they swing hard depending on the pathway, which is the part we will spend the most time on below.
The honest way to read that table is by your own block, not by the average. A two-bedroom on a flat suburban lot with the sewer running down the back boundary is a different project from the same two-bedroom on a sloping site where the nearest connection is forty metres uphill. The drawing is identical. The cost is not. For a city-by-city breakdown of real quotes against real builds, we have separate guides for granny flat costs in Sydney and granny flat costs in Brisbane, and a state-by-state look at two-bedroom prices.
New South Wales
New South Wales has the most mature granny flat framework in the country, and it shows. The rules are clear, the fast pathway is genuinely fast, and most standard projects qualify for it. The catch is that the framework is prescriptive, which means it does not bend. You either meet the standard or you do not, and the slab does not negotiate.
Approval Pathway
NSW gives you two roads. The fast one is Complying Development, approved through a private accredited certifier rather than council under the State Environmental Planning Policy that governs housing, known as the Housing SEPP. If your design meets every prescribed standard, the certifier can issue a Complying Development Certificate, or CDC, without the project ever touching a council planning officer. The slow one is a Development Application, or DA, lodged with council, which is where you go when your site or design falls outside the prescribed standards.
Most standard granny flats in Sydney qualify for the CDC pathway. That is the design target, because the difference in time and cost between the two roads is large.
Size and Setbacks
Under the Housing SEPP, a secondary dwelling is capped at 60m² of internal floor area. To use the CDC pathway, the lot must be at least 450m² and at least 12 metres wide at the building line. Maximum building height is 8.5 metres. The rear setback is at least 3 metres, and side setbacks are 0.9 metres for walls under 4.5 metres in height, increasing to 1.5 metres above that.
One rule catches people who think they have found a loophole. A lot with a secondary dwelling cannot be subdivided, and you are allowed exactly one principal dwelling and one secondary dwelling on the site. You cannot quietly turn one block into two titles by building a granny flat first.
Fees and Timeline
The CDC pathway is the reason people build in NSW. A complying development certificate for an eligible granny flat is typically issued in 10 to 20 business days, with certifier and assessment costs commonly in the $3,000 to $5,000 range. The DA pathway, by contrast, runs 40 to 90 days and $5,000 to $10,000 once you account for council fees and the consultants a DA tends to drag in.
That gap is months of holding costs and interest. It is worth designing to the standard.
Common Traps
We had a client buy a flat-pack granny flat kit before he spoke to anyone about approvals. His block was 449m². One square metre under the 450 threshold, and the entire CDC pathway was off the table. He went from a twenty-day certificate to a full DA, and the kit sat under a tarp in his yard for the better part of five months while council worked through it. The kit was fine. The land was the problem, and nobody had checked the land.
The other one we see constantly is the easement. A drainage or sewer easement running through the back of the block is invisible until a certifier reads the title, and you cannot build over it. People design a beautiful rear granny flat sitting square on top of the council’s stormwater line and only find out when the plans get knocked back. We read the title before we draw a line. It is the cheapest insurance in the project.
Not sure which permit pathway applies to your project?
Not sure whether your NSW project is a CDC or a DA? Check your permit pathway before you commit to a design.
Victoria
Victoria spent years being the hard state for second dwellings, and then changed its mind in a serious way. The small second dwelling reforms removed the planning permit for most of these projects, and the practical effect has been to turn Victoria from a slow state into a fast one almost overnight. There is a sting in the detail, though, and it is the lot size.
Approval Pathway
A small second home of 60m² or less no longer requires a planning permit in most cases, provided the lot is 300m² or larger and carries no flooding, environmental, or other special planning controls. That is a genuine reform, not a tweak. You skip the planning permit entirely and go straight to the building permit.
A building permit is always required. The planning permit is the one that has been removed, not the building approval, and people conflate the two constantly. You still need a registered building surveyor, you still need compliant architectural drafting plans, and you still need to build to code. You just skip the months-long planning queue.
Size and Setbacks
The exemption applies to a gross floor area of 60m² or less. The dwelling must be self-contained, which Victoria defines plainly: a kitchen sink, food preparation facilities, a bath or shower, and a toilet and wash basin. There can be only one existing dwelling on the lot and only one small second dwelling. A small second home cannot be connected to reticulated natural gas, and it does not require a car parking space, which removes two of the old sticking points in one move.
Because these are new Class 1a dwellings, they must meet the current National Construction Code energy provisions, which now means a 7-star NatHERS rating, the Whole-of-Home standard, and the Livable Housing Design requirements. That is the cost that has moved in 2026, and we cover it in the design section below.
Fees and Timeline
With the planning permit gone, the timeline collapses to the building permit process, which a building surveyor can typically turn around in weeks rather than months for a straightforward design. Your costs shift accordingly, away from planning consultants and toward the surveyor and the energy report. The reform did not make the build cheaper. It made the approval faster and more predictable, which on a financed project is often worth more than the dollars.
Common Traps
The 300m² floor is where the disappointment lives. A client on a tight inner-suburban infill block, around 280m², read the headlines about permits being scrapped and assumed she was clear. She was not. Under 300m², a planning permit is always required, reform or no reform. We still got it through, but it was a planning application she had budgeted zero time for, and the timeline tripled against what she expected.
The other trap is the overlay. The exemption falls away the moment your block carries a flooding, bushfire, heritage, or other special control, and a surprising number of Melbourne blocks carry at least one. The reform reads as a blanket freedom in the news. It is a freedom with conditions, and the conditions are written on your planning certificate, not in the headline. We pull that certificate before we promise anyone a permit-free pathway.
Queensland
Queensland made the change that mattered most to investors and quietly stopped talking about it. For years a secondary dwelling in Queensland could only be occupied by a member of the household. You could build a granny flat, but you could not rent it to a stranger. That restriction is gone, and it has been gone long enough now that the market has fully repriced around it.
Approval Pathway
There is no single statewide approval for granny flats in Queensland the way there is in NSW. Each local council sets its own rules, and many treat a compliant secondary dwelling as accepted development, meaning no development application is required if you meet the standards. Others require a DA. The practical first step in Queensland is always the same: confirm how your specific council treats it, because Brisbane City Council and a regional shire can land in very different places.
Size and Setbacks
This is the part people get wrong by trusting a number they read about a different council. There is no statewide maximum size for a secondary dwelling in Queensland. Each council sets its own gross floor area cap, and it varies by zone, by lot size, and sometimes by precinct within a zone. Brisbane City Council commonly allows up to around 80m², which is more generous than the 60m² that anchors the southern states, but that figure is a Brisbane figure, not a Queensland figure. Your council may sit well below it.
Fees and Timeline
Where a project is accepted development, the timeline is short, because there is no planning assessment to wait on; you move to building approval. Where a DA is triggered, you are into council assessment timeframes, which vary by local government. Fees follow the same split. The honest answer to “how long and how much” in Queensland is “tell me your council first,” and anyone who quotes you a statewide figure has not read your specific planning scheme.
Common Traps
The change to rental rules took effect on 26 September 2022 and removed the family-only occupancy restriction, so any new secondary dwelling can be rented to anyone. The trap sits with the older stock. We have had clients who built before that date, on the old understanding, and assumed they were free to list the flat the moment the rule changed. The reform applies cleanly to new dwellings, and the position on older approvals depends on the conditions attached to the original permit, so the answer is “check the approval you actually hold,” not “the law changed, so I am fine.”
The size assumption is the other one. A client planned an 80m² two-bedroom because a Brisbane builder’s website said 80m² was the Queensland standard. His council, not Brisbane, capped it lower for his zone. The design came back to the board, and the lesson was the usual one. Read your scheme, not someone else’s brochure.
Tasmania
Tasmania is the state to watch in 2026, because the rules are changing underneath us as we write. If you are reading this in the second half of the year, check the date on the section, because the headline number is in motion.
Approval Pathway
Under the Tasmanian Planning Scheme, if the zone permits a single dwelling, it generally permits a secondary residence as well. You may not need planning approval at all if your project meets the requirements for a secondary residence and all of the development standards for your zone. Building and plumbing approval are always required regardless. The pathway is closer to Victoria’s new model than to the prescriptive NSW certifier system, and it leans heavily on whether your design stays inside the development standards.
Size and Setbacks
Here is the live change. The State Planning Provisions currently allow a secondary residence of up to 60m². In March 2026 the state announced work to amend the planning scheme and lift that cap to 90m², and the Minister has issued the terms of reference for amendment 01-2026 to do exactly that. As we publish, the 60m² cap is still the law. The 90m² figure is a proposal in process, not a permission you can design to yet. A secondary residence also cannot have separate service connections for electricity, water, or sewerage; it shares the main dwelling’s connections.
Fees and Timeline
Where the project meets the standards and avoids a planning application, the timeline is short and the cost sits with building and plumbing approval rather than planning assessment. Where it triggers a planning permit, you are into council timeframes. As with Queensland, the number depends on your council and your zone, so the useful work happens at the planning certificate, not at the brochure.
Common Traps
The 90m² announcement is the trap of the year. People read “Tasmania is lifting granny flats to 90m²” and want to design a 90m² dwelling today. The scheme has to actually change first, and amendments take time and can shift in detail along the way. We are designing Tasmanian projects to the current 60m² rule, with an eye on the amendment, rather than betting a client’s build on a reform that is not yet law. Designing to a rule that does not exist yet is how you end up holding plans you cannot lodge.
The service connection rule catches the rest. Because a secondary residence cannot have its own separate connections, a design that assumes a standalone power and water hookup, the way you might in NSW, will not comply. It changes where the building can sensibly sit on the block, and that is a drawing decision, not an afterthought.
Design: where the money is actually won or lost
Approval gets the attention because it is the part that frightens people. The design is where the money actually moves, and it gets a fraction of the thought. That is backwards.
Lead with this principle: every dollar you spend on a good drawing saves several on the slab. The single most expensive thing in any small build is a change made after construction has started. Moving a wall on paper costs an eraser. Moving it once the frame is up costs a variation, a delay, and a trade standing around being paid to wait. We have watched clients try to save two thousand dollars on drawings and lose twenty thousand to a kitchen that had to be relocated because the plumbing was never properly set out.
The big design decision in 2026 is the same one it has always been, just with sharper edges: custom design against an off-the-shelf kit. A kit is cheaper on the sticker and faster to a brochure price, and on a flat, simple, unconstrained block it can be the right call. The moment your block has a slope, an easement, an awkward orientation, or an overlay, the kit fights the site, and you pay for that fight in site costs and compromises. A custom design works with the block instead of against it. It is the difference between buying a suit off the rack and having one cut. Both cover you. One fits.
The other shift this year is energy compliance, and it is not optional. New Class 1a dwellings now have to meet the current National Construction Code provisions, which means a 7-star NatHERS rating and the Whole-of-Home standard. That changes glazing, insulation, orientation, and shading, and it is far cheaper to design in from the first sketch than to bolt on after a failed assessment. A granny flat designed to hit 7 stars from the start barely costs more than one that ignores it. A granny flat redesigned to pass after the fact costs a fortune.
If you want to see how far a smart layout stretches a small footprint, our guide to 60m² granny flat designs shows custom layouts built to stay inside the permit-free thresholds in NSW and Victoria.
What Draftee does at this stage
This is the part we are actually for. We draw secondary dwellings that fit the block, hit the energy standard, and stay inside the approval pathway that keeps your project fast. We do not build them and we do not sell kits, so the only thing we are optimising is your plan. Talk to us about your block.
Approvals, owner-builders, and the order you do things in
Most of the pain we see comes from doing things in the wrong order. People buy the kit, then check the lot size. They design the dwelling, then read the planning certificate. They pour the slab, then discover the easement. The work is the same work either way. Done in the right order it is a project. Done backwards it is a series of expensive surprises.
The order that works is simple. Pull your planning certificate and your title first, so you know your zone, your overlays, your easements, and your lot dimensions before you fall in love with anything. Confirm your approval pathway second, because in NSW that decides whether you are designing to the CDC standard, and in Queensland and Tasmania it decides whether you need a planning permit at all. Design to that pathway third. Then, and only then, get builder quotes against a real set of drawings rather than a vague description, which is the only way a fixed price is actually fixed.
Owner-builders sit slightly outside this and still need every step of it. If you are managing your own build, you take on the coordination a builder would normally carry, and the plans become more important, not less, because they are the instructions every trade works from. The owner-builder who searches “granny flat DIY” is usually capable of swinging a hammer and entirely unaware of how a 0.9 metre setback or a 7-star glazing requirement will reshape their plan. The drawing is where that knowledge lives. We cover what an owner-builder can and cannot do themselves in our granny flat DIY guide, and the realistic build timeline in our stage-by-stage timeline.
If a granny flat does not suit your block, the same logic applies to a shed-to-dwelling conversion or a full owner-builder permit pathway. The states change. The order does not.
Planning a renovation? Use the owner-builder checklist.
Managing your own build? Start with the owner-builder checklist so nothing in the sequence above gets skipped.
Frequently Asked Questions
In 2026, a finished granny flat build typically runs from around $120,000 for a small one-bedroom to over $250,000 for a two or three-bedroom, before site costs. Utility connections add roughly $3,000 to $8,000, and approval costs are separate again and depend on your state’s pathway. The brochure base price is rarely the final figure, because site conditions, slope, and service distances are added back afterwards. Price your own block, not the average.
In most cases yes, if your lot meets your state’s requirements. NSW allows a secondary dwelling through Complying Development on lots of at least 450m². Victoria allows a small second dwelling of up to 60m² without a planning permit on most lots of 300m² or more. Queensland and Tasmania generally allow one where the zone permits a single dwelling. The deciding factors are your lot size, your zone, and any overlays, which all sit on your planning certificate. Pull that certificate before you commit to anything.
The order matters more than anything else. First, pull your title and planning certificate to confirm your zone, overlays, easements, and lot dimensions. Second, confirm your approval pathway, which differs by state. Third, get compliant plans drawn to that pathway. Fourth, obtain your approval, whether that is a CDC, a building permit, or a council DA. Only then do you get fixed-price builder quotes against real drawings and begin construction. Doing these steps out of order is the most common way people lose money on a granny flat.
A granny flat, known formally as a secondary dwelling or small second dwelling, is a self-contained home built on the same lot as an existing main house. It has its own kitchen, bathroom, and entrance, which is what separates it legally from a converted room or a studio with a sink. Each state uses a slightly different name and applies different size caps and approval rules, but the core idea is consistent across Australia.
Generally one. In NSW the Housing SEPP allows exactly one principal dwelling and one secondary dwelling per lot, and that lot cannot be subdivided on the strength of the granny flat. Victoria allows one existing dwelling plus one small second dwelling. Queensland and Tasmania similarly work on a one-secondary-dwelling basis, subject to the local scheme. If you want more than two dwellings on a block, you are no longer in granny flat territory; you are looking at dual occupancy or subdivision, which are different processes entirely.
A granny flat agreement is a formal arrangement, usually between family members, setting out a person’s right to live in a granny flat in exchange for money, transferred assets, or care, most often in an ageing-parent situation. It is a legal and financial arrangement rather than a building approval, and it carries Centrelink and tax implications worth getting advice on. It is separate from the planning and construction approvals this guide covers. We are not lawyers or financial advisers, so for a granny flat agreement specifically, speak to one before money or property changes hands.
Related Reading
- Granny Flat Cost Sydney 2026: Real Prices for 1, 2, and 3-Bedroom Builds
- Granny Flat Cost Brisbane 2026: Real Prices by Bedroom Count
- 2 Bedroom Granny Flat Prices 2026: State-by-State Breakdown
- 60m² Granny Flat Designs: Permit-Free Custom Layouts for NSW & VIC
- Granny Flat DIY 2026: What Owner-Builders Can Actually Do Themselves
- How Long Does It Take to Build a Granny Flat? Stage-by-Stage Timeline
- Shed to Dwelling Conversion 2026: State Guide
Draftee provides architectural drafting and design. We are not the builder and we do not sell kits, which is the point. Regulatory details in this guide reflect the rules in force in June 2026 and change regularly, particularly in Tasmania where amendment 01-2026 is in progress. Confirm the current position for your own site before you commit. We are not lawyers or financial advisers; for granny flat agreements and tax questions, get professional advice.
Last updated and changelog
Last updated: 3 June 2026
Changelog:
– 3 June 2026: Initial publication. Rules current as at June 2026. TAS amendment 01-2026 (60m² to 90m²) flagged as in progress.
