Victoria’s backyard second home can now be a third bigger. The size limit grabbed the headlines, but the way floor area is measured and what still triggers a permit have shifted as well.

Victoria lifted the small second dwelling limit from 60 to 80 square metres

Since 15 October 2026, a small second dwelling in Victoria can have a total floor area of up to 80 square metres. The change came through Amendment VC306, which rewrote the definition at Clause 73.03 of every planning scheme in the state, according to the Department of Transport and Planning.

Small second dwelling is the legal name for what most of us call a granny flat. It is a self contained home on the same lot as an existing house, and it sits outside the old dependent person’s unit rules that tied occupancy to a dependent person.

The 60 square metre cap had been in place since 14 December 2023, when Amendment VC253 created the category and removed the planning permit for most lots.

What counts as a small second dwelling in Victoria

Under Clause 73.03 of the Victoria Planning Provisions, a small second dwelling is a building, or part of a building, with a total floor area of no more than 80 square metres, on the same lot as an existing dwelling and used as a self contained residence. It must include a kitchen sink, food preparation facilities, a bath or shower, and a toilet and wash basin.

The building regulations have been brought into line

For a short window the planning and building systems disagreed. When VC306 started, the department said matching changes to the Building Regulations 2018 and the Minister’s guideline on siting and design would follow soon after.

In a news update dated 29 October 2026, the department said the Building Regulations 2018 had been amended to align with the planning provisions.

That alignment matters on every job. Even where no planning permit is needed, a building permit still is, and the relevant building surveyor assesses the work against the Building Regulations.

Decks and verandahs no longer count toward the floor area

VC306 also rewrote how the planning floor area is measured. It runs to the outside surface of the external walls, or to the centre of a party wall shared with another building.

Attached or abutting unroofed patios, pergolas, porches and terraces are left out of the calculation. So are attached roofed decks, verandahs and other roofed structures.

Under the 2023 building rules, the 60 square metre total included all roofed areas. A covered deck on the side of a unit came straight out of the space available for the home itself.

A covered deck on the side of a unit came straight out of the space available for the home itself.

The access path rule is gone from the planning scheme

VC306 deleted the planning requirement to provide an access pathway to the small second dwelling. The department’s stated reason was to remove duplication with the liveable housing design standard.

Accessibility has not left the picture. A small second dwelling is a Class 1a building, and the National Construction Code provisions that apply to a new Class 1a home apply to it as well.

Most of the approval rules have not moved

The bigger envelope sits inside the same approvals framework, and the licensing and compliance obligations that apply to any new home still apply here. A building permit is normally required, including where a planning permit is also needed.

A planning permit is still triggered in a residential zone where the lot is under 300 square metres, and in the Rural Conservation, Green Wedge and Green Wedge A zones. Overlays and other provisions of a planning scheme can also trigger one.

In a Heritage, Design and Development or Neighbourhood Character Overlay, no permit is needed if the building is 5 metres or less in height and finished in muted tones and colours.

No car parking space is required. A small second dwelling cannot be connected to reticulated natural gas, so it cannot run off the mains gas network. There is no restriction on who can live in one, and the rental minimum standards apply when it is let.

The transitional rules for dependent person’s units expire on 28 March 2027.

The official guidance has not all caught up

As at 10 November 2026, the Building and Plumbing Commission’s consumer page on small second dwellings still described a floor area limit of 60 square metres. The page showed it was last updated on 30 June 2026.

On the same date, the department’s own small second homes page, last updated on 15 October, still said the building system changes were yet to follow. A number of council fact sheets also still carried the 60 square metre figure.

Clients, valuers and lenders searching for the rules can easily land on any of these pages first.

An extra 20 square metres opens up a different job

At 60 square metres, fitting two bedrooms and a separate living area was tight. At 80, with outdoor structures excluded from the count, there is more room to work with, along with more slab, more frame and a higher contract price.

The pool of eligible sites is large. Department analysis found around 700,000 residential lots of 300 square metres or more eligible for a small second home, plus roughly 2,450 in rural zones. That figure dates from the 60 square metre rules and counts eligible lots, not likely builds.

Because there is no restriction on who can live in a small second dwelling, the same 80 square metre unit can serve an ageing parent, an adult child or a paying tenant over its life.

That flexibility ties into the growing pull of multigenerational living in Australian housing.

Other states are moving in the same direction

South Australia lifted its ancillary accommodation limit from 60 to 70 square metres through a Planning and Design Code amendment approved in November 2024.

Tasmania has a draft amendment to raise the secondary residence limit from 60 to 90 square metres. It was on public exhibition from 10 June to 22 July 2026 and then went to the Tasmanian Planning Commission for assessment.

In Western Australia, the draft Residential Design Codes would lift the exempt granny flat size from 70 to 90 square metres, with submissions open until 26 February 2027. New South Wales remains at 60 square metres under its Housing SEPP.

Set against the wider trends shaping housing supply, Victoria’s 80 square metre limit sits above the current caps in South Australia and New South Wales, while the Tasmanian and Western Australian drafts would go further.

The new limit is settled. The paperwork around it is not

Both the planning scheme and, by the department’s account, the building regulations now work to an 80 square metre limit. The rule itself is no longer the moving part.

What is still moving is the material sitting around it: consumer pages, council fact sheets and plans drawn up before October. The job most exposed is the one priced or designed from a figure that has since changed.

The Good Builder Take

Bigger granny flats are good news for small builders and modular operators, and for clients trying to house family close by. The 20 extra square metres are the easy part. The measurement change and the stale guidance are where the margin and the arguments sit.

Anyone quoting 60 to 80 square metre units right now is working ahead of some of the official paperwork. That makes a clear scope, drawn to the current definitions, worth more than it was a month ago.

Building small second dwellings at the new size? We want to hear how the first 80 square metre jobs are landing with your surveyors and clients. Get in touch with our team.

Frequently asked questions

Related articles

• WA Draft Codes Would Let Granny Flats Grow to 90 Square Metres
• From Necessity to Norm: Why Multigenerational Living Is Redefining Home Design

Last updated: 14 November 2026

General information only. This article is general information and does not take into account your particular circumstances. It is not legal, planning, building or financial advice. Planning and building requirements vary by site and change over time. Check the current requirements with the relevant planning authority and a registered building surveyor before acting.

Author: TGB Editorial