Do I Need a Planning Permit for My Extension? Planning, Building Permits and VicSmart Explained

A client asked me earlier this year, about a backyard studio we were designing: "So the fast-track (VicSmart) approach doesn't apply?"

It was a fair hope. VicSmart is quick, it isn't advertised to the neighbours, and the name sounds like exactly what a small project deserves. But the studio had big openings to the garden, which made it a habitable room, and the house was in a heritage overlay. My answer was blunt: if we lodge it under VicSmart, it will simply be rejected.

Planning permit, building permit and VicSmart get used interchangeably, but they're three different things, and which ones apply to your project decides your timeline more than almost anything else. Here's the one-page version.

Two permits, two different questions

A planning permit asks: can you build this, here? It's issued by your council and deals with how a building sits in its street: heritage, character, overlooking, overshadowing, trees, flooding and bushfire.

A building permit asks: will it be built safely? It's issued by a registered building surveyor (private or council) and checks the design against the Building Regulations: structure, fire safety, energy efficiency, wet areas and, where no planning permit is involved, the siting rules too.

Almost every extension needs a building permit. Only some need a planning permit. When a planning permit is needed, it comes first, and the building permit has to match it.

What triggers a planning permit for an extension?

For one house on one lot in Victoria's main residential zones, it comes down to three things.

1. The size of your lot

Since 2023 the statewide line has been 300 m². On a lot of 300 m² or more, building or extending a single house doesn't need a planning permit under the zone. Your building surveyor checks the siting rules (setbacks, boundary walls, site coverage and so on) instead of council.

On a lot under 300 m², which covers plenty of terraces and workers' cottages in the inner west and inner north, you do need a planning permit. Since 8 September 2025, though, there's a clearer path. If the design meets a set of state "deemed to comply" standards for small lots, it can go through VicSmart. More on that below.

2. Overlays

This is where a lot of inner-west and inner-north projects get caught. An overlay sits on top of the zone and can bring back a planning permit regardless of lot size.

• Heritage Overlay. Extending a house in a heritage overlay needs a planning permit, even when the extension is at the back and can barely be seen. Internal changes generally aren't controlled. (Our Hobsons Bay heritage guides go through what each precinct controls.)
• Flood overlays, such as the Land Subject to Inundation Overlay you'll find around Echuca and elsewhere in Campaspe. These almost always trigger a permit and usually come with floor-level requirements.
• Bushfire Management, Design and Development or Significant Landscape overlays. These depend on the schedule and the size of the work, so check them one by one.

3. Everything that isn't on the planning map

More than one dwelling on the lot, a covenant or section 173 agreement on your title, or a large canopy tree near the back fence can all add a permit or limit what you can build. Read your title before you plan anything.

You can check your address in a couple of minutes with our free planning permit check and heritage check. They're a starting point, not a planning certificate.

What VicSmart is (and what it isn't)

VicSmart is a streamlined planning permit process for straightforward applications. Council has 10 business days to decide, and the application isn't advertised to neighbours. It's genuinely useful when it fits.

It fits a defined list of things, not "anything small". For homeowners that list includes:

• a single house or extension on a lot under 300 m² that meets the deemed-to-comply standards
• minor buildings and works such as carports, garages, pergolas, verandahs, decks and sheds
• certain minor works in a heritage overlay
• removing some canopy trees on residential land

It doesn't stretch to cover projects outside those classes, which is what tripped up our backyard studio. A shed can be VicSmart. A studio with large glazed openings that you'll work or sleep in is a habitable building, and in a heritage overlay it needs a full permit. Lodging it the wrong way doesn't save time. It gets bounced and you start again.

So before anything is lodged, I check the pathway with council. It's a short conversation that saves weeks.

A note on what's coming

The Planning Amendment (Better Decisions Made Faster) Act 2026 will bring in a tiered system, with faster decisions and fewer neighbour notice and appeal rights for simple applications such as single dwellings. Most of it isn't in force yet (the deadline is 29 October 2027), so for now the rules above apply.

Speak to your building surveyor before you lodge

My strong advice is to appoint your building surveyor early and talk to them before lodging: ask what they need to see and whether anything will raise questions. A surveyor who gets a complete package doesn't have to stop, ask, wait and ask again.

Don't forget the retaining walls

Retaining walls often get treated as "just landscaping". A wall over 1 m high needs a building permit, and some lower walls do too when they're close to a boundary or another structure.

My rule is simple: if the project needs a retaining wall, put it in the building permit, so it's part of the builder's documented scope and covered by their insurance. Leaving it to a separate little job later is how a wall ends up with no permit, no engineering and nobody responsible when it starts to lean.

Where to start

1. Check your address with the heritage check and planning permit check, and read your title.
2. If there's an overlay or your lot is under 300 m², assume a planning permit and plan your timeline around it.
3. Confirm the pathway with council before anything is lodged.
4. Appoint a building surveyor early and ask what they need.

If your property has an overlay, a Clarity Consultation is a good next step. In about 90 minutes we work through your site, the permits it's likely to need and a realistic path to a builder. For an example of a small project done well inside a heritage overlay and around a sewer easement, have a look at the Garden Pod Over the Pond.

Frequently asked questions

Do I need a planning permit to extend my house in Victoria? Not always. For one house on a lot of 300 m² or more in a main residential zone, you usually don't, unless an overlay applies (heritage, flooding, bushfire and others) or something on your title says otherwise. On a lot under 300 m² you do, although a design that meets the state's standards can go through the 10-day VicSmart process.

What's the difference between a planning permit and a building permit? A planning permit, from council, decides whether you can build this on your site, looking at things like heritage, neighbours and character. A building permit, from a registered building surveyor, checks that it will be built safely and to the Building Regulations. Almost every extension needs a building permit, and some need both.

What is VicSmart? VicSmart is Victoria's fast-track planning process for a defined list of simple applications, with a 10-business-day decision and no advertising to neighbours. It covers things like compliant houses on small lots, sheds, decks, carports and some minor heritage works. Projects outside those classes, such as a habitable studio in a heritage overlay, need a full planning permit.

Do I need a permit for a retaining wall? You need a building permit for a retaining wall over 1 m high, and possibly for a lower wall close to a boundary or another building. If your project needs one, include it in the main building permit so it's engineered, documented and covered by the builder's insurance.

Sources: Planning Victoria (Amendment VC282 and the one-dwelling-on-a-lot guide, 2025), Amendment VC243 (2023), Planning Victoria's update on the Better Decisions Made Faster Act (2026), Monash City Council's VicSmart guide and Boroondara City Council's retaining wall guidance. General information only, not planning advice. Your council's planning scheme governs, so check your own property with council or a building surveyor.

Header image: Ernest Geldart, Bungalow drawing (front elevation), 1911. The Metropolitan Museum of Art, via Wikimedia Commons. Public domain.