A Victorian granny flat up to 60 m2 may skip planning, but it still needs a building permit
In Victoria, a small second dwelling up to 60 m2 can avoid a planning permit in many cases, but it still needs a building permit. Planning can still be triggered by lots under 300 m2, overlays, title restrictions and local controls. Larger dual-occupancy builds need a fuller planning pathway.
The permit thresholds that decide the pathway
| Project situation | Planning permit position | Building permit position | What to check before quoting |
|---|---|---|---|
| Small second dwelling up to 60 m2 | Often no planning permit if siting, amenity and planning scheme requirements are met | Building permit still required | Zone, overlays, title restrictions, easements and services |
| Lot under 300 m2 | Planning permit can be required in Frankston and other Victorian planning schemes | Building permit still required | Private open space, setbacks, overlooking and site coverage |
| Heritage, bushfire, flood, erosion or special building overlay | Planning permit may be triggered even for a small second dwelling | Building permit still required | Overlay schedule, BAL assessment, flood level or erosion controls |
| Second dwelling over 60 m2 | Usually a fuller planning pathway, not the small second dwelling shortcut | Building permit required | ResCode-style siting, neighbourhood character and car access |
| Subdivision or separately saleable dwelling | Planning permit and subdivision process expected | Building permit required | Services, driveway, title, open space and council contributions |
| Non-habitable garden studio with no kitchen or bathroom | May be simpler, depending on size and siting | Building permit may still apply by size and structure | Whether it is truly non-habitable and not represented as a dwelling |
The 60 m2 number is not a design target for every family. It is the planning shortcut threshold for a small second dwelling. If you need a larger two-bedroom granny flat, a subdivision-ready dual-occupancy dwelling or an NDIS SDA-compliant build, the approval pathway needs to be checked as a separate design decision.
The instruments that actually matter
The rules sit across planning, building, contracts and trade licensing. A builder who says "council does not matter anymore" is oversimplifying. A builder who says every granny flat needs a full planning permit is also oversimplifying. The correct answer starts with the address.
| Instrument or authority | What it controls | Practical effect on your quote |
|---|---|---|
| Planning and Environment Act 1987 and the Victorian planning schemes | Use and development of land, overlays, local controls and planning permit triggers | Decides whether the small second dwelling can use the simpler pathway or needs planning assessment. |
| Frankston Planning Scheme and Mornington Peninsula Planning Scheme | Local zoning, overlays, neighbourhood controls and title-related planning issues | Changes the answer between Frankston, Seaford, Mt Eliza, Mornington and Mt Martha. |
| Building Act 1993 and Building Regulations 2018 | Building permits, building surveyor role, occupancy and enforcement | Creates the building permit and inspection pathway even when planning is not needed. |
| National Construction Code 2022 | Structure, fire, health, amenity, energy efficiency and access requirements | Sets the technical baseline for a lawful habitable dwelling. |
| NatHERS and Victorian 7-star energy rules | Thermal performance and Whole of Home energy assessment | Affects orientation, glazing, insulation, heating, cooling, hot water and sometimes solar readiness. |
| AS/NZS 3500 plumbing and drainage standards | Water, sewer, stormwater and drainage installation | Matters heavily on long service runs, low blocks and stormwater detention. |
| AS 3740 waterproofing standard | Wet-area waterproofing | Bathroom and laundry compliance needs certificates, not just a neat tile finish. |
| AS 1428.1 and the SDA Design Standard where relevant | Access and Specialist Disability Accommodation design | Applies when the brief is accessible or NDIS SDA, not to every basic family granny flat. |
| Domestic Building Contracts Act 1995 | Major domestic building contracts, deposits and payment rules | For work over $10,000, contract paperwork and deposit limits matter before money changes hands. |
| Building and Plumbing Commission registration system | Builder and plumbing practitioner registration | Lets you check the practitioner before signing or paying a deposit. |
What the council trigger means in Frankston and the Peninsula
Frankston City’s small second dwelling guidance reflects the Victorian reforms, but it also points homeowners back to the planning scheme, overlays and formal property advice. For example, a lot under 300 m2 can still trigger a planning permit. Heritage, Bushfire Management, Special Building, Erosion Management and other overlays can also change the pathway. Title restrictions, covenants, building envelopes and easements can override a design that otherwise looks fine.
Mornington Peninsula properties often need a more careful overlay check because coastal, bushfire, erosion, vegetation and neighbourhood-character constraints vary street by street. Mt Eliza, Mt Martha and Mornington blocks can look generous on land size but still have tree, slope or covenant constraints that affect siting. Seaford and Carrum Downs blocks may have drainage and lower-land issues that show up in the building permit and civil design rather than planning.
The practical move is simple: check the property report, title, overlays and service locations before you pay for detailed drawings. If the design is a standard one-bedroom granny flat under 60 m2 on an uncomplicated lot, the approval work may be straightforward. If the goal is separate rental yield, future subdivision or a larger short-stay Peninsula dwelling, treat planning as part of the investment decision.
Need the permit pathway checked before design?
Send the address and preferred dwelling size. We will check the obvious planning and building triggers before recommending the next step.
What goes wrong at sale time or claim time
Unapproved dwellings usually look cheapest at the beginning and most expensive at the end. At sale time, a buyer’s conveyancer, building inspector or lender can ask for permits, occupancy evidence and compliance certificates. If the structure was advertised as a self-contained dwelling but approved as a shed or studio, the problem becomes a valuation and disclosure issue.
At insurance claim time, undocumented electrical work, plumbing, waterproofing, drainage or structural changes can be difficult to defend. A leaking bathroom in an unapproved backyard dwelling is not only a repair bill. It can expose missing waterproofing certificates, missing occupancy approval and a building permit problem. Fixing paperwork after the walls are lined is far harder than doing it before the slab.
None of this means you should overbuild. If you only need a quiet office with no bathroom, a simpler garden studio may be the cheaper and more honest option. If you need a parent, adult child, tenant or participant to live there, price it as a dwelling from day one and compare with the 2026 pricing guide.
Check the Victorian permit pathway for your block
Send the address and target floor area and we will reply within 1 business day with the likely approval path to confirm.