How Much Does It Cost to Build a Granny Flat in Australia in 2026?
A state-by-state guide to 2026 prices, planning rules, hidden costs, and a worked Sydney budget.
This guide is for Australian homeowners and small investors planning a detached granny flat ("secondary dwelling") on a residential lot anywhere in Australia. If you only have five minutes, read the short answer below and jump to your state.
Building a detached two-bedroom granny flat in Australia in 2026 typically costs $150,000 to $260,000 turnkey, with most owners landing in the $180,000–$220,000 range once site costs, council fees, and service connections are included. Kit and modular options can start lower; architect-designed or two-storey builds frequently push past $300,000. Adelaide consistently produces the cheapest builds; Canberra and Darwin sit at the most expensive end. New South Wales and Victoria are not the cheapest to build in, but they have the fastest approval pathways, which often makes them the most cost-efficient overall.
Every figure in this guide is sourced from primary publications — the Australian Bureau of Statistics, Cotality (formerly CoreLogic), Master Builders Australia, Turner & Townsend, RLB, and state planning departments — with builder-derived ranges flagged as such.
Important: this is general information. Construction prices and planning rules change quickly. Figures are estimates current to mid-2026, not quotes. Always obtain at least three written, fixed-price quotes from licensed local builders and confirm current planning rules with your council before budgeting your project.
At a glance — granny flat costs across Australia
The table below shows typical 2026 turnkey ranges for a 60 m² two-bedroom detached granny flat on a flat metro lot with services close by. Difficult sites can add $15,000–$50,000+. See the methodology for how the ranges are derived.
| State / Territory | Typical 2026 turnkey cost | Approval pathway | Max floor area (fast-track) |
|---|---|---|---|
| New South Wales | $170,000 – $230,000 | Complying Development Certificate (CDC) or DA | 60 m² |
| Victoria | $160,000 – $215,000 | Building permit only on qualifying lots | 60 m² |
| Queensland | $170,000 – $230,000 | Varies by council planning scheme | Set by council |
| Western Australia | $170,000 – $225,000 | Building permit only where R-Codes deemed-to-comply | 70 m² |
| South Australia | $155,000 – $205,000 | Development approval always required | 70 m² |
| Tasmania | $160,000 – $215,000 | Permitted use in most residential zones | 60 m² (90 m² proposed) |
| ACT | $200,000 – $260,000 | Development Application required | 90 m² |
| Northern Territory | $210,000 – $290,000 | Often no planning approval required | 75 m² residential / 80 m² rural |
What counts as a granny flat?
"Granny flat" is colloquial — every state uses a different formal term: secondary dwelling (NSW, QLD), small second dwelling (VIC), ancillary dwelling (WA), ancillary accommodation (SA), secondary residence (TAS, ACT), dwelling-independent (NT). Whatever the name, the common features are: a self-contained home with its own kitchen, bathroom, and at least one bedroom, on the same title as a primary house, that generally cannot be subdivided or sold separately. Maximum floor areas under each state's fast-track pathway are in the table above.
The 2026 cost picture — what's driving prices
House construction costs are still rising, but more slowly. The ABS Producer Price Index for House Construction rose 4.2% in the year to March 2026 and 1.1% in the March quarter (ABS, Producer Price Indexes, Australia, March 2026). The ABS Insights series shows house construction output prices rose roughly 42% from December 2019 to mid-2024. Most of that increase happened in 2021–2023 (ABS, Insights into Output of Building Construction Prices).
Cotality's Cordell index agrees. The CCCI, one of the most widely quoted construction cost benchmarks in Australia, recorded its strongest quarterly result of 2025 in the December quarter. It rose 1.0% q/q for an annual rate of 2.5% (Cotality, Cordell CCCI December 2025).
Trade shortages are baked into pricing. Master Builders Australia warned in 2025 that 180,500 homes were started in 2024–25 (almost 60,000 short of the National Housing Accord target), and the industry needs roughly 90,000 additional tradespeople (Master Builders Australia, 2025).
Forward outlook for 2026. RLB forecasts continued cost escalation across Australian capitals in 2026: Sydney +4.0%, Melbourne +4.0%, Brisbane +5.0%, Perth +5.3%, Adelaide +5.1% (RLB, Construction cost escalation to remain elevated in 2026). Build in another 3–5% on top of today's quotes for late-2026 starts.
Cost per square metre and total build cost
Detached granny flat builds in 2026 generally fall into one of three tiers. Turner & Townsend's 2025 GCMI puts capital-city all-construction averages between A$4,133/m² (Adelaide, cheapest) and A$5,009/m² (Brisbane, most expensive), with Sydney at $4,866 and Melbourne at $4,242 (Turner & Townsend GCMI 2025). That's a useful comparative ranking, but granny flat builds usually land below those all-construction figures. A small detached dwelling is structurally simpler than the apartment and commercial mix baked into the headline number.
| Tier | Cost per m² | Total cost (60 m²) | What you typically get |
|---|---|---|---|
| Builder-grade | $2,500 – $3,500 | $150,000 – $220,000 | Standard plan, basic finishes, vinyl/laminate, electric cooking, single split system |
| Mid-range | $3,500 – $4,500 | $200,000 – $280,000 | Better fixtures, stone benchtops, double glazing, ducted or multi-zone AC |
| Premium / custom | $4,500 – $6,000+ | $280,000 – $400,000+ | Architect design, high-end finishes, energy-efficient envelope, possibly two-storey |
Tier ranges are widely used in the Australian granny flat market and broadly align with the all-construction $/m² benchmarks above. They are builder-derived ranges, not figures from a single primary publication. Quantity-surveyor handbooks such as the Rawlinsons 2026 Australian Construction Handbook publish more granular per-element figures behind a paywall.
Kit and modular routes sit below the builder-grade tier. A factory-built modular granny flat delivered turnkey is typically $130,000–$200,000; an owner-assembled kit can land at $60,000–$120,000 if you manage the trades yourself, but the gap closes quickly once you factor in slab, plumbing, electrical, and certification.
Want to see what these tiers actually buy before collecting quotes? Buildana publishes its complete standard-plan range with fixed-price tiers and full inclusions. Looking at what a builder-grade 60 m² plan includes, and what a mid-range upgrade adds, makes it much easier to read a generalist builder's "from $X" quote.
New South Wales
Typical 2026 turnkey cost: $170,000 – $230,000 for a 60 m² two-bedroom granny flat on a flat Sydney metro lot.
Planning rules. Secondary dwellings in NSW are governed by State Environmental Planning Policy (Housing) 2021, Chapter 3 Part 1. The previous SEPP (Affordable Rental Housing) 2009 was repealed when the Housing SEPP commenced on 26 November 2021 (NSW Department of Planning). Maximum internal floor area is 60 m² and minimum lot size is 450 m². No restriction on who can rent.
"SEPP Housing 2021 definitely changed the market by bringing different housing policies into one framework and creating clearer pathways for certain housing types. Compared to the old ARH SEPP, it's made the planning environment broader, but also more detailed, so developers and homeowners need to understand the controls properly before assuming a project is straightforward."
— Oliver Alameri, Founder of Buildana (Western Sydney, NSW Licence 487805C). This guide's fact-checker.
Approval pathway. If your project meets every Codes SEPP standard, an accredited certifier can issue a Complying Development Certificate (CDC) in roughly 10–20 business days. Otherwise you lodge a Development Application with council, typically 8–16 weeks (NSW Planning Portal — Codes SEPP).
Section 7.11 contributions. Most Sydney councils charge a developer contribution. Blacktown, for example, charges $3,985 for a one-bedroom and $5,535 for a two-bedroom secondary dwelling (Blacktown CP3). Most Sydney councils sit in the $4,000–$8,000 range; growth-area LGAs can be above $10,000.
| Specification | Sydney metro | Regional NSW |
|---|---|---|
| 1-bed, 45 m², builder-grade | $140,000 – $175,000 | $125,000 – $155,000 |
| 2-bed, 60 m², mid-range | $170,000 – $230,000 | $155,000 – $200,000 |
| 2-bed, 60 m², premium | $230,000 – $300,000 | $200,000 – $270,000 |
Victoria
Typical 2026 turnkey cost: $160,000 – $215,000 for a 60 m² two-bedroom granny flat on a flat Melbourne metro lot.
Planning rules. Victoria removed the planning permit requirement for small second dwellings up to 60 m² in the Residential Growth, General Residential, and Neighbourhood Residential zones on lots over 300 m² via Amendment VC253, gazetted 14 December 2023. Building permit only — issued by a registered building surveyor — but flooding, heritage, or environmental overlays can re-trigger the planning permit requirement (Victorian Building Authority). No rental restriction; cannot be subdivided or sold separately (Victorian Government).
Cost context. Melbourne's all-construction $/m² average sits below Sydney and Brisbane in the Turner & Townsend data, which flows through to slightly cheaper builds. Victoria's granny flat builder market is also less mature than NSW's, so the spread between cheapest and most expensive quotes can be wider. Get at least three.
| Specification | Melbourne metro | Regional Victoria |
|---|---|---|
| 1-bed, 45 m², builder-grade | $135,000 – $170,000 | $120,000 – $155,000 |
| 2-bed, 60 m², mid-range | $160,000 – $215,000 | $145,000 – $195,000 |
| 2-bed, 60 m², premium | $215,000 – $290,000 | $195,000 – $265,000 |
Queensland
Typical 2026 turnkey cost: $170,000 – $230,000 in South-East Queensland. Brisbane is now the most expensive Australian capital for general construction work per Turner & Townsend's 2025 data, which has flowed through to granny flat pricing.
Planning rules. Queensland's Planning Regulation 2017 was amended on 26 September 2022 to remove the rule that secondary dwellings could only be occupied by members of the same household — anyone can now rent a granny flat in Queensland (Queensland Department of State Development, Infrastructure and Planning). There is no statewide maximum floor area; size limits and siting rules are set by each local government's planning scheme. Brisbane, Gold Coast, Logan, and Sunshine Coast councils all have slightly different limits (commonly 50–80 m²) — check yours before designing.
Approval pathway. Building approval is always required. Whether a development approval is also needed depends on the local planning scheme — many councils accept secondary dwellings as "accepted development subject to requirements". RLB's forecast Brisbane escalation rate for 2026 is 5.0%, the highest of the eastern capitals.
| Specification | Brisbane / SEQ | Regional QLD |
|---|---|---|
| 1-bed, 45 m², builder-grade | $140,000 – $175,000 | $125,000 – $160,000 |
| 2-bed, 60 m², mid-range | $170,000 – $230,000 | $155,000 – $205,000 |
| 2-bed, 60 m², premium | $230,000 – $310,000 | $205,000 – $280,000 |
Western Australia
Typical 2026 turnkey cost: $170,000 – $225,000 in Perth for a 60 m² two-bedroom ancillary dwelling.
Planning rules. Ancillary dwellings are governed by State Planning Policy 7.3 — Residential Design Codes Volume 1. The maximum plot ratio area is 70 m². On 10 April 2024 the previous 350 m² minimum lot size was removed — R-Code-compliant ancillary dwellings can now be built on residential lots of any size and on grouped/strata lots in all R-codings (DPLH info sheet, April 2024). If the dwelling complies with deemed-to-comply provisions, no planning approval is required — building permit only. No rental restriction.
Cost context. WA construction costs are tightly linked to the resources sector. Perth's RLB-forecast 2026 cost escalation is 5.3%, the highest of any capital. Remote WA (Pilbara, Kimberley) costs meaningfully more than Perth. Builder estimates put the premium anywhere from 30% to 60%, depending on access and how aggressively resource-sector projects are competing for the same trades.
| Specification | Perth metro | Regional WA |
|---|---|---|
| 1-bed, 45 m², builder-grade | $140,000 – $175,000 | $135,000 – $175,000 |
| 2-bed, 60 m², mid-range | $170,000 – $225,000 | $165,000 – $220,000 |
| 2-bed, 60 m², premium | $225,000 – $300,000 | $220,000 – $310,000 |
South Australia
Typical 2026 turnkey cost: $155,000 – $205,000 in Adelaide. SA is consistently the cheapest mainland state for residential construction — Adelaide had the lowest all-construction $/m² of any capital in the Turner & Townsend 2025 data.
Planning rules. Ancillary accommodation is governed by the Planning and Design Code. The maximum floor area was raised from 60 m² to 70 m² in 2024 — early-commenced 29 February 2024 and formally adopted by the Minister on 18 November 2024 (SA Planning). The previous family-only restriction was removed on 16 November 2023 — anyone can now rent ancillary accommodation in SA (SA Planning Commission).
Approval pathway. Development approval (planning consent + building rules consent) is always required in SA — there is no no-permit pathway equivalent to NSW's CDC or Victoria's small second dwelling exemption (SA Planning FAQ).
| Specification | Adelaide metro | Regional SA |
|---|---|---|
| 1-bed, 45 m², builder-grade | $120,000 – $150,000 | $110,000 – $140,000 |
| 2-bed, 60 m², mid-range | $155,000 – $205,000 | $140,000 – $185,000 |
| 2-bed, 60–70 m², premium | $205,000 – $270,000 | $185,000 – $250,000 |
Tasmania
Typical 2026 turnkey cost: $160,000 – $215,000 in Hobart or Launceston.
Planning rules. Tasmania's secondary residence provisions sit in the Tasmanian Planning Scheme — State Planning Provisions (current version effective 25 December 2024). The current maximum floor area is 60 m² (State Planning Office). In March 2026 the Minister issued Terms of Reference for SPP Amendment 01-2026, which proposes to lift the cap to 90 m² (Tasmanian State Planning Office) — this is not yet law, so assume 60 m² applies to your project.
Cost context. Tasmania has a small builder pool and most building products are freighted from the mainland, which pushes prices a little above Adelaide despite lower land costs. Wet-weather days during construction also extend timelines outside the major centres.
| Specification | Hobart / Launceston | Regional TAS |
|---|---|---|
| 1-bed, 45 m², builder-grade | $130,000 – $165,000 | $130,000 – $170,000 |
| 2-bed, 60 m², mid-range | $160,000 – $215,000 | $160,000 – $220,000 |
| 2-bed, 60 m², premium | $215,000 – $285,000 | $215,000 – $300,000 |
Australian Capital Territory
Typical 2026 turnkey cost: $200,000 – $260,000 for a secondary residence in Canberra.
Planning rules. Secondary residences are governed by E01 — Residential Zones Policy (notifiable instrument NI2023-540) under the Territory Plan 2023, in force from 27 November 2023. Maximum floor area 90 m² (ACT Planning). A Development Application is always required (no complying-development equivalent).
Don't confuse with dual occupancy. The ACT has a separate "dual occupancy" pathway. On RZ1 blocks larger than 800 m², a dual occupancy can be up to 120 m² and the second dwelling can be unit-titled and sold separately. A "secondary residence" cannot. If a builder is quoting a "granny flat" that's actually a dual occupancy, the rules and economics are different — confirm which pathway you're on.
Cost context. Canberra labour rates are among the highest in Australia, reflecting a small construction workforce competing with public-sector capital works. Canberra projects routinely sit a noticeable margin above equivalent regional NSW for like-for-like work.
| Specification | Cost range |
|---|---|
| 1-bed, 45 m², builder-grade | $160,000 – $200,000 |
| 2-bed, 60 m², mid-range | $200,000 – $260,000 |
| 2- or 3-bed, 90 m², premium | $285,000 – $390,000 |
Northern Territory
Typical 2026 turnkey cost: $210,000 – $290,000+ in Darwin for a 60 m² cyclone-rated dwelling-independent. The NT is the most expensive jurisdiction in Australia for granny flat construction, driven by freight, a small trade pool, and mandatory cyclone-rated construction in Darwin.
Planning rules. Granny flats are called "dwelling-independents" in the Northern Territory Planning Scheme 2020. The maximum floor area was raised on 1 December 2023 to 75 m² in residential zones and 80 m² in rural zones (NT Government). In most cases planning approval is not required if the proposal meets all NT Planning Scheme requirements; building approval through an NT-registered building certifier is always required.
Cyclone construction. Darwin sits in cyclone Region C under AS 4055:2021 Wind loads for housing, which prescribes wind classifications C1–C4 for cyclonic regions (HIA). Cyclone-rated construction adds engineering, tie-down, and bracing costs that don't apply on the east coast.
| Specification | Darwin (cyclone-rated) | Alice Springs |
|---|---|---|
| 1-bed, 45 m², builder-grade | $170,000 – $220,000 | $155,000 – $200,000 |
| 2-bed, 60 m², mid-range | $210,000 – $290,000 | $195,000 – $260,000 |
| 2-bed, 60–75 m², premium | $290,000 – $370,000 | $260,000 – $340,000 |
A realistic Sydney budget — line by line
An itemised budget for a typical 2026 Sydney project: a 60 m² two-bedroom granny flat in Western Sydney, on a flat lot with services close by, mid-range finishes, built under Complying Development. Treat as a worked example, not a quote.
| Item | Indicative cost |
|---|---|
| Site survey, contour and soil test | $2,500 |
| Architectural plans and engineering | $4,500 |
| Complying Development Certificate (private certifier) | $3,500 |
| Section 7.11 / 7.12 council contributions | $5,535 (Blacktown 2-bed; check your council) |
| Slab and site preparation | $22,000 |
| Frame, roof, external cladding (lock-up) | $45,000 |
| Windows, external doors | $9,000 |
| Internal linings, doors, joinery | $22,000 |
| Kitchen (cabinetry + appliances) | $14,000 |
| Bathroom and laundry fitout | $11,000 |
| Plumbing rough-in and fitoff | $13,000 |
| Electrical, data, lighting | $10,000 |
| Split-system air conditioning | $3,500 |
| Service connections (water, sewer, electrical sub-board) | $8,500 |
| Driveway and basic landscaping | $6,000 |
| Builder margin and overheads (~12%) | $22,500 |
| Total | ≈ $202,500 |
The Section 7.11 figure uses the actual Blacktown City Council 2-bedroom rate. Builder margin is in the 10–15% range commonly used for small detached builds; trade-by-trade allocations are illustrative based on typical 60 m² granny flat specifications.
Hidden costs to budget for
Headline build prices routinely exclude items that can add $15,000–$50,000+ to your real-world budget. "From $130,000" advertising rarely includes the items below.
Site costs
- Site survey and contour plan: $800–$2,500
- Soil test (geotechnical): $500–$1,500
- Tree removal / arborist report: $1,000–$10,000+
- Site cut, fill, retaining: $5,000–$30,000 on sloped sites
- Demolition of existing structure: $5,000–$20,000
Council, fees, and approvals
- Complying Development Certificate (NSW): $2,500–$5,000
- Development Application (where required): $3,000–$8,000
- Building permit and certification: $1,500–$4,000
- Section 7.11 / 7.12 contributions (NSW): roughly $4,000–$10,000+ depending on LGA — see Blacktown CP3 for an example
Service connections
- Separate water meter: $2,000–$6,000
- Sewer connection or extension: $3,000–$15,000+
- Electrical sub-board / new connection: $2,000–$8,000
- Stormwater connection: $1,500–$5,000
- NBN / telecoms: $300–$1,500
Finishing and outdoor
- Driveway, fencing, landscaping: $8,000–$45,000 combined depending on scope
- Window furnishings and air conditioning: $3,000–$9,500 combined
How to keep costs down without cutting corners
The single biggest cost lever on a Sydney build is design complexity. Oliver Alameri, who runs Buildana in Western Sydney and project-manages roughly five LGAs' worth of jobs a year, puts it bluntly:
"The cheapest way to build in Sydney is to keep the design simple, efficient, and standardised — fewer structural complexities, simpler roof forms, and lightweight material selections. The most expensive way is usually custom luxury work with complex architectural details, high-end finishes, difficult site conditions, and constant design changes during construction."
— Oliver Alameri, Founder of Buildana
That principle drives most of the practical tactics below.
Get at least three written, fixed-price quotes from licensed builders. Verify each licence with the relevant state regulator: NSW Fair Trading, VBA, QBCC, Building and Energy WA, CBS SA, CBOS Tasmania, Access Canberra, NT Building Practitioners Board.
Choose a standard design. Builders price their standard plans aggressively because the engineering is already done. Custom design is the single most common reason quotes blow out.
Build close to the main house to share existing service connections. Running a sewer line 30 metres can cost more than the slab.
Avoid sloped or rocky sites where possible. Site costs scale faster than build costs. Consider prefab or modular if your site suits it; factory build cuts labour cost and weather delays.
Insist on fixed-price contracts, not Provisional Sums. Provisional Sums frequently blow out, especially on site costs, electrical, and tiling.
Red flags in builder quotes
The single biggest trap is comparing on headline price without comparing on scope.
"The biggest mistake homeowners make is comparing quotes only by the final price, without checking what's actually included and excluded. A cheaper quote can become more expensive later if it has low allowances, missing scope items, or unclear specifications."
— Oliver Alameri, Founder of Buildana
Specific things to watch for:
- "From $X" advertising usually excludes site costs, council fees, and connections. Ask for a "complete on-site, ready-to-move-in" total before comparing builders.
- Vague Provisional Sums like "site costs $5,000" without itemised scope.
- No home warranty insurance. NSW requires Home Building Compensation Fund cover for residential work over $20,000 (icare); Victoria requires Domestic Building Insurance over $16,000 (VBA); QBCC's Queensland Home Warranty Scheme kicks in at $3,300 (QBCC).
- Deposits over the legal cap. In NSW, the maximum deposit on a residential building contract is 10% of the contract price (NSW Fair Trading).
- Pressure to sign quickly, refusal to provide references, or no fixed business address.
Financing and rental returns
Most major Australian lenders treat granny flats as standard residential construction lending. Common funding paths are a construction loan, a redraw or offset on an existing mortgage, or a home equity facility. ASIC Moneysmart has neutral guidance on construction finance.
On rental returns. Granny flat rents are not separated out as a category in any major published rental dataset, so any specific weekly figure is an industry estimate rather than a primary statistic. Property Council of Australia commentary citing CoreLogic notes that a two-bedroom self-contained secondary dwelling can add roughly 27% to a property's weekly rent and more than one percentage point to its gross yield (Property Council of Australia). Builder commentary commonly puts Sydney granny flat rents in the $400–$650 per week range — treat any specific figure as indicative. Always factor in vacancy, management fees, maintenance, insurance, land tax, and CGT exposure when modelling returns; SQM Research publishes Sydney weekly rent data for sanity-checking.
This is not financial advice. Speak to a licensed mortgage broker, a registered tax agent (search the Tax Practitioners Board public register), or an independent financial adviser before making investment decisions.
Step-by-step plan from idea to handover
- Confirm your lot is eligible. Check zoning, lot size, easements, and overlays via your state planning portal or council.
- Order a site survey, contour plan, and soil test ($2,000–$4,000 combined). Required by every quoting builder; reveals site issues early.
- Get three written, fixed-price quotes from licensed local builders. Verify each licence. Compare scope, not just headline price.
- Confirm financing with your lender before signing a contract.
- Sign a written contract with scope, fixed price, payment schedule (within the legal deposit cap), warranty insurance, and completion timeframe.
- Lodge for approval (CDC, building permit, or DA as your pathway requires).
- Inspect at each stage: slab, frame, lock-up, fixoff, completion. Don't make progress payments until each stage is genuinely complete.
Frequently asked questions
How long does it take to build a granny flat?
Typically 12–20 weeks on site for a standard build, plus 4–12 weeks for design and approval (much faster under complying development). Prefab and modular builds can be installed in 6–10 weeks on site once the slab is ready.
Can I sell the granny flat separately from the main house?
For a true secondary dwelling, no — it shares the title with the primary house and cannot be subdivided. The only exception is the ACT's separate "dual occupancy" pathway on RZ1 blocks larger than 800 m², where the second dwelling can be unit-titled. That's a different planning pathway and a different cost profile.
Do I need a builder, or can I owner-build?
Owner-builder rules vary by state. In NSW, owner-builders must complete an owner-builder course and obtain an owner-builder permit for works above the prescribed threshold. Most states have similar requirements. Owner-building can reduce build costs (chiefly by removing the builder's margin) but exposes you to all coordination, defect, and warranty risk. Defects on owner-built work generally aren't covered by state home warranty schemes.
How much value does a granny flat add to my property?
Industry valuer rules of thumb commonly put resale-value uplift at roughly 60–80% of build cost in metropolitan markets. This is a generalisation, not a guarantee — uplift depends heavily on local rental demand and design quality. The investment case for most granny flats rests on rental income rather than capital gain. For site-specific guidance, get a valuation from a registered valuer (search the Australian Property Institute directory).
Methodology and sources
Cost ranges are compiled from publicly available sources current to mid-2026:
- ABS Producer Price Indexes, March 2026 and ABS Insights into Output of Building Construction Prices — residential cost change over time.
- Cotality Cordell Construction Cost Index — December 2025 quarter.
- Turner & Townsend GCMI 2025 — capital city $/m² used to derive state cost differentials.
- RLB 2026 escalation forecasts.
- Master Builders Australia 2025 housing target commentary.
- State planning departments and instruments linked in each state section; state licensing regulators linked above.
Limitations. Aggregate cost sources don't isolate granny-flat figures, so per-square-metre rates have been applied to typical 60 m² dwellings to derive ranges. State cost differentials use the published capital-city benchmarks. Specific granny flat weekly rents and gross yields are not in any primary published dataset and are presented as industry estimates. The Section 7.11 figures cited come from Blacktown's published contributions plan; your council's plan will differ. These are estimates, not quotes. Always validate with multiple fixed-price quotes from licensed local builders.
Last reviewed
May 2026. Construction prices and planning regulations change frequently. If reading more than six months after the review date, treat figures as a starting point and verify current builder pricing and planning rules.
Disclaimer
General information only — not financial, legal, tax, or construction advice. Cost ranges are estimates from publicly available sources and may not reflect what you will pay on your specific site. Planning rules change. Always obtain professional advice and written quotes specific to your project, lot, and council. Word of Mouth and the author accept no liability for decisions made in reliance on this guide.