Granny flat or extension for a parent in Melbourne?

Answering: Granny flat (second dwelling) or home extension: how do you decide which way to add space for a parent on a Melbourne site?

Estimated reading time: 13 min read

Build a granny flat, which Victoria’s planning system calls a small second dwelling, when your parent still runs their own day and wants their own front door; extend the house when they need help within earshot, or when the lot has no real room behind it. Since 15 October 2026 a small second dwelling can be up to 80 square metres, not 60, and on a Melbourne residential lot of 300 square metres or more it normally needs no planning permit, only a building permit. Barbara Yerondais, FRAIA, a fixed-fee renovation and extension architect with 35+ years in practice, works through this choice with families before anyone draws, and her practice, BY Projects Architecture, has delivered more than 400 projects across Victoria.

It is Sunday lunch, and Mum took the front steps one at a time again, holding the rail with both hands. Everyone noticed and nobody said anything until the dishes were done. Then the quiet argument started: one sibling wants her in the spare room by Christmas, another has a quote for a flat out the back. Nobody at the table knows which one your block, your council and your budget will allow.

Put the flat on a site that cannot take it and you lose the garden, the money and possibly the argument with council. Build the extension for a parent who prizes independence and you may give her a lovely room she quietly resents.

Below: the new rules, where they tip the choice on your lot, which option serves your parent, and who does what.

Key Insights

• From 15 October 2026, Amendment VC306 lets a Victorian small second dwelling reach 80 square metres, as long as it is fully self-contained.
• On a residential lot of 300 square metres or more, a small second dwelling normally needs no planning permit unless another control requires one; under 300 square metres in the main residential zones, a granny flat and an extension both need a planning permit assessed against Clause 54.
• In a Heritage Overlay the usual order flips: an extension generally needs a planning permit, while a small second dwelling up to 5 metres high in muted tones and colours does not need one under that overlay.
• A small second dwelling cannot be subdivided or sold separately, anyone may live in it or rent it, and the Building and Plumbing Commission says it cannot be connected to reticulated gas.

Table of Contents

• Victoria’s granny flat grew to 80 square metres on 15 October 2026.
• Lot size, overlays and title decide which path is open.
• Your parent’s answer depends on how help travels at two in the morning.
• The two paths carry different rules on title, rent and services.
• A surveyor, a planner, a builder and an architect each own a different piece.
• Five steps settle the choice before anyone pays for drawings.

What a granny flat is in Victoria since 15 October 2026

In Victoria’s planning schemes, a granny flat is a small second dwelling: a building, or part of a building, on the same lot as an existing home, used as a self-contained residence. Planning Victoria’s small second homes guidance sets out what Amendment VC306 changed.

• The size. Total floor area went from 60 to 80 square metres. For a parent, 20 more square metres can mean a separate bedroom rather than a studio.
• The measure. Floor area is measured from the outside of the external walls, and an attached roofed deck or verandah is not counted in it.
• The access path. VC306 deleted the planning requirement for an access pathway, to remove duplication with the Livable Housing Design Standard in the National Construction Code.
• The form. The Building and Plumbing Commission notes it can be attached, detached or a conversion of an existing building.

Here is the catch. Planning Victoria says the building system will reflect VC306 through changes to the Building Regulations 2018 and Minister’s Guideline 12, to follow soon after gazettal, and the Building and Plumbing Commission’s own page still listed 60 square metres when we read it on 20 October 2026. Ask your building surveyor to confirm in writing that an 80 square metre design can be permitted before you pay anyone to draw it.

An older option, the movable dependent person’s unit, survives only under transitional provisions at Clause 52.04 that expire on 28 March 2027.

Where the planning rules tip the choice on your lot

Before anyone argues about floor plans, pull the Planning Property Report for your address through VicPlan: it shows your zone, every overlay, and any heritage register or bushfire listing.

• The 300 square metre line. On a residential lot of 300 square metres or more, a small second dwelling normally needs no planning permit, and under the single home code an extension to one house is in most cases checked at the building permit. Below 300 square metres in the main residential zones, both need a planning permit assessed against Clause 54.
• A Heritage Overlay. Under a Heritage Overlay you generally need a planning permit for exterior alterations and new construction, so an extension goes to council. A small second dwelling in a Heritage, Design and Development or Neighbourhood Character Overlay does not need a permit under that overlay if it is no more than 5 metres high and finished in muted tones and colours. Works to the heritage house itself still go to council. On a heritage street, the quiet single-storey flat behind the house can be the lighter planning path, and the practice Barbara Yerondais leads brings a record of 59+ heritage approvals to that call.
• Your title. A registered restrictive covenant or a section 173 agreement can limit what you build, whatever the planning scheme says.

Then look at the ground. Minimum garden area applies to all Neighbourhood Residential Zone land and specified General Residential Zone land, small second dwellings included, so the flat, any future extension and the garden your parent wanted to sit in all come out of the same backyard. Barbara Yerondais’s practice has lodged 200+ permit applications, a record rather than a promise: nobody can guarantee a council outcome for your site, so we confirm your lot’s position before anyone draws.

Which option serves your parent, now and in ten years

The rules tell you what you may build; your parent’s next ten years tell you what you should.

A separate flat buys independence. Your parent keeps their own front door, routine, television volume and visitors. For a parent who still cooks and runs their week, that dignity is the point. The cost is distance: every check-in is a walk across the garden in July rain, at two in the morning.

An extension buys proximity. Help is a door away and meals are shared without a coat. The cost is privacy on both sides, and the risk is a parent who feels like a guest in your kitchen.

An attached second dwelling sits between them. A small second dwelling can be part of a building, so a self-contained wing sharing a wall with the house, with its own kitchen, bathroom and entry, is a legitimate option.

• Walk the route from your back door to theirs at night, in winter, carrying a cup of tea.
• Ask who helps, at what hour, and whether that person sleeps in your house or theirs.

For a small second dwelling, the Livable Housing Design Standard is assessed with the building permit, including access to the home from the property boundary. Barbara Yerondais’s practice has worked in the aged-care sector, and the detailed design moves for a parent’s flat are in our guide to designing a granny flat so Mum or Dad actually live well.

What each choice means for money, title and the years after

A small second dwelling is a second home on your one title, and Victorian law keeps it that way: a planning permit cannot be granted to create a separate lot for land containing one, so it is never a subdivision play.

• Who lives there later. Anyone may live in a small second dwelling: after your parent, an adult child or a tenant, with rental laws, including the rental properties minimum standards, applying once it is let. An extension simply becomes more of your house.
• Services and rates. Ask your utility provider whether the flat can share the house’s services, and council whether it will be separately rated. It cannot be connected to reticulated gas, so plan hot water, heating and cooking without it.
• The build contract. Either way, structural work needs a building permit, and Consumer Affairs Victoria says a builder must use a major domestic building contract once the job costs more than $10,000.

On cost, be wary of anyone who prices the job before seeing the block: siting, drainage, services and access move the price more than the label on the plan. Barbara Yerondais fixes her fee before design begins and stages the work: schematic design first, then two options side by side, one showing what your budget achieves and one showing what the full wish list costs, so the scope is your decision. A granny flat is exactly the kind of smaller project we welcome. For the family maths on care itself, read what keeping a parent close actually costs in Victoria.

Who does what on a granny flat or extension

A home for a parent usually involves several professionals, each owning a different piece, and the order you bring them in matters.

• The building surveyor issues the building permit and checks the design against the building regulations, so theirs is the written answer on 80 square metres you want first.
• The town planner prepares and argues a planning permit application where one is needed, such as on a lot under 300 square metres or where an overlay applies. On a heritage street, a heritage consultant can advise how new work affects the place.
• The builder prices the build and constructs it, under a major domestic building contract once the job costs more than $10,000.
• A building designer or draftsperson draws plans for permit, often the right fit for a simple flat on an open, unconstrained lot.
• Barbara Yerondais, a fixed-fee renovation and extension architect, works out whether your block, budget and your parent’s care point to a flat or an extension before anyone draws, then designs it for a fixed fee, working alongside the surveyor, planner and builder.

Five steps to decide before anyone draws

1. Pull the Planning Property Report and write down the zone, every overlay and the lot area against the 300 square metre line. Ask your building surveyor where 80 square metres stands.
2. Order the title and look for a restrictive covenant or a section 173 agreement.
3. Write the care picture on one page: what help your parent needs now, what help is likely next, and who gives it at night.
4. Walk both routes, the garden path and the hallway, and mark every step, threshold and tight turn where a fall, a wheelchair or a carer would struggle.
5. Talk to Barbara. The first call is free and carries no obligation, and if the project is a fit, a one-hour Feasibility Session follows.

On the booking form, choose “Granny flat or second dwelling” as the project type, or “Not sure yet” if the extension is still in the running.

Closing

A granny flat suits a parent still running their own life on a lot that can spare some garden; an extension suits a parent who needs help through a door. The 80 square metre limit makes the flat a more liveable home, and the heritage exemption can make it the easier permit too. Barbara Yerondais’s practice has also designed more than 235 community and social housing dwellings since 2009, across 10+ Victorian councils, so small self-contained homes are familiar ground. To see how we approach both paths, visit our pages on granny flats and second dwellings in Melbourne and home extension architects in Melbourne. Then bring your property report, your title and your parent’s next ten years to the table.

Frequently asked questions about granny flats and extensions for a parent

Q: Do I need a planning permit to build a granny flat for my parent in Melbourne?

A: Often not. A small second dwelling is permitted in all residential zones and normally needs no planning permit on a residential lot of 300 square metres or more, unless another control in the planning scheme requires one, such as some overlays. On a lot under 300 square metres in the main residential zones it needs a planning permit assessed against Clause 54. A building permit is normally required either way, and your council can confirm the position for your address.

Q: Can I build an 80 square metre granny flat now?

A: The planning rules allow it from 15 October 2026, when Amendment VC306 raised the limit from 60 square metres. Planning Victoria says matching changes to the Building Regulations 2018 and Minister’s Guideline 12 are to follow, and the Building and Plumbing Commission’s page still showed 60 square metres when we read it on 20 October 2026. Ask your building surveyor to confirm the current position before the design is drawn to 80.

Q: Can we rent the granny flat out or sell it separately later?

A: You can rent it. Planning Victoria says there are no restrictions on who can live in a small second dwelling, and rental laws, including the rental properties minimum standards, apply once it is let. You cannot sell it separately: a planning permit cannot be granted to create a separate lot for land containing a small second dwelling, so it stays with the main house.

Q: What happens when I talk to Barbara about a granny flat or an extension?

A: It starts with a free, no-obligation call; Barbara rings you herself to see whether the project is a fit. If it is, the one-hour Feasibility Session follows. In one hour with Barbara Yerondais, FRAIA, in person or on Zoom, you’ll talk through your site, budget and planning timelines, and leave knowing what’s realistic and what your next step is. There’s no obligation to go further.

Where this advice comes from

Barbara Yerondais, FRAIA, is a fixed-fee renovation and extension architect with 35+ years in practice, and BY Projects Architecture has delivered more than 400 projects across Victoria, from family homes to community housing. We would rather tell you the flat will not fit than draw one that leaves your parent cold, lonely or a long way from help.

Citations

• Small second homes, Planning Victoria (Department of Transport and Planning). Defines a small second dwelling as up to 80 square metres from 15 October 2026 (Amendment VC306, previously 60 under VC253); no planning permit normally needed in residential zones unless the lot is under 300 square metres or another provision applies; the Heritage, Design and Development and Neighbourhood Character Overlay exemption at 5 metres and muted tones; no separate lot, no car parking, no occupancy restriction; building regulation changes to follow; dependent person’s unit transitional provisions to 28 March 2027. https://www.planning.vic.gov.au/guides-and-resources/strategies-and-initiatives/small-second-dwellings
• Small second dwelling, Building and Plumbing Commission. A small second dwelling can be attached, detached or a conversion, cannot be subdivided from the primary dwelling, cannot be connected to reticulated gas, must meet the minimum garden area on all Neighbourhood Residential Zone land and specified General Residential Zone land, and needs a building permit; the page still listed 60 square metres when read on 20 October 2026. https://www.bpc.vic.gov.au/home-owners/home-renovation-and-building-essentials/small-second-dwelling
• Single home code, Planning Victoria. Clause 54 applies to single dwellings and small second dwellings, including alterations and extensions, on lots under 300 square metres in the main residential zones, where a planning permit is required; above 300 square metres it in most cases does not apply and siting is assessed with the building permit. https://www.planning.vic.gov.au/guides-and-resources/guides/all-guides/residential-development/single-home-code
• Local heritage protection, Planning Victoria. A property in a Heritage Overlay generally needs a planning permit from council for demolition, exterior alterations and new construction. https://www.planning.vic.gov.au/guides-and-resources/guides/all-guides/local-heritage-protection
• Planning property report, Planning Victoria. The free summary of zone, overlays, Victorian Heritage Register status and bushfire prone area for any Victorian address, through VicPlan. https://www.planning.vic.gov.au/planning-schemes/planning-property-report
• Extensions and renovations costing more than $10,000, Consumer Affairs Victoria. Structural work needs a building permit, and a builder must use a major domestic building contract for work costing more than $10,000. https://www.consumer.vic.gov.au/housing/building-and-renovating/checklists/extensions-and-renovations-costing-more-than-10000

Related Reading on housing a parent close to home

• We’ve decided to build a granny flat for Mum or Dad: how should we design it so they actually live well?
• Granny flat or aged care: what does keeping a parent close actually cost in Victoria?
• Ageing in place in a heritage home: accessibility without losing the character
• Should you extend out or add a second storey in Melbourne?
• What does one hour settle before a renovation design contract?

About the Author

Barbara Yerondais, FRAIA, is the founder of BY Projects Architecture. With 35+ years of experience, she specializes in sustainable, community-focused design and heritage restoration. A dedicated mentor and rower, Barbara balances her high-impact Melbourne practice with a passion for social inclusion and passive, energy-saving design.