Building & renovating / VICTORIA
Can I build an 80 m² granny flat in Victoria?
Check the planning and building rules, title restrictions and wastewater before paying for a small second home.
Check the site before choosing a unit
Put the proposed home, access and services on one plan. Use the brief to ask the question that could change your purchase.
Prepare a granny flat enquiry →An 80 m² granny flat can fall within Victoria’s current planning definition of a small second dwelling. That does not approve the site or remove the building-permit process. Before choosing a unit, put its actual footprint on a plan and check the questions below.
Why official pages show both 80 m² and 60 m²
The state planning guide describes the VC306 planning definition of a small second dwelling up to 80 m². The planning-scheme amendment register records 14 October 2026 as its operation date, while the government guide describes the changes as taking effect 15 October 2026; those descriptions must not be silently treated as the same event. A separate government announcement dated 29 October 2026 confirms that the Building Regulations 2018 have now been updated to align the small-second-dwelling building requirements with the planning changes. Older BPC or guide text may still refer to 60 m² or say that building changes are pending. Ask the building surveyor to identify the applicable current building provision, proposed class, permit and any relevant transitional application before paying for a unit. The 80 m² definition is not an automatic planning- or building-permit exemption.
A building permit is required. The building assessment covers matters such as siting, access and construction. A prefabricated or “tiny home” label does not settle those requirements. BPC small second dwellings
Six checks before you choose a unit
| Check | What may change the pathway | Useful next question |
|---|---|---|
| Residential lot size | A lot under 300 m² generally needs a planning permit for the small second dwelling. | What is the title area and exact zone? |
| Rural zone | Green Wedge, Green Wedge A and Rural Conservation zones need specific checks; other rural zones can trigger permits for earthworks or setbacks. | Which use and development conditions apply in this zone? |
| DDO, Heritage or Neighbourhood Character Overlay | The small-second-dwelling exemption in these overlays requires height no more than 5 m and muted finishes. | Does this design meet that particular exemption? |
| Other controls and trees | Other overlays and vegetation controls can still require a permit. | Show the whole footprint, access, excavation and trees on the plan. |
| Title restrictions | A covenant or Section 173 agreement may affect a second residence. | Give the full instrument to your conveyancer or solicitor, not just its title reference. |
| Services | Reticulated gas cannot be connected. Sewer availability and wastewater capacity need checking. | What connection or wastewater work is required and included in the quote? |
The first five checks follow the state planning guidance; the gas restriction is also identified by BPC. Passing one row does not answer the others. A larger lot or a low roof is not, by itself, a no-permit finding.
Ask for the actual area calculation
The planning definition uses all floors measured to external wall faces or party-wall centres; specified attached outdoor structures are excluded. Ask the supplier to show the calculation, rather than relying on a model name such as “80”. Definition and measurement
Keep two drawings together: the unit’s floor plan and a site plan showing the existing house, boundaries, trees, easements, delivery route and proposed connections. A unit may fit on paper but still leave no practical delivery route or usable outdoor space. Mark estimated dimensions and missing records clearly.
On an unsewered Peninsula property, check capacity early
Council’s wastewater guidance requires report and consent under Building Regulation 132 for building work involving wastewater-system installation or alteration. Additional rooms or fixtures can increase the design load even when the tank stays put. Council also uses 7.5 m² as part of a bedroom-load assumption for a self-contained room without another clearly defined function, unless contrary evidence is supplied. It is not a universal room-size exemption or an automatic instruction to replace a tank.
Send Environmental Health the existing wastewater permit, system layout and proposed floor plan. Ask whether the additional load can be accommodated and what assessment is needed. Keep the disposal area clear of the proposed unit, decks and access works. Resolve this before requesting a firm installation price.
Example: an 80 m² unit on a large block
Suppose the owner has a large residential lot, a DDO and an old septic plan. The unit’s advertised size answers only the first question. The owner can request the area calculation and a section showing height, then mark the septic layout on the same site plan. A designer can test an alternative position if the unit conflicts with the disposal area. Council and the surveyor can then answer defined questions about that proposal, instead of receiving an unexplained brochure.
Start with the uncertainty that could change the purchase. A missing title instrument, unknown service capacity or unresolved building pathway deserves attention before selecting paint colours or commissioning every possible report.
Get a quote you can use
- Separate the unit price from delivery, crane access, footings, excavation, connections and wastewater work.
- Name who prepares the site drawings and handles each application, inspection and requested revision.
- Ask which site assumptions could change the price and what is excluded.
- Keep the same drawing revision and scope when approaching different suppliers.
AI can organise those records and draft questions. It cannot confirm the legal effect of a covenant, wastewater capacity or building compliance. Keep unanswered items visible in the brief and ask the relevant professional or authority to resolve them.
Check the site before choosing a unit
Put the proposed home, access and services on one plan. Use the brief to ask the question that could change your purchase.
Prepare a granny flat enquiry →