Granny Flat Checker — can a second dwelling be built on this Victorian address?
Enter any Victorian address. The checker pulls the parcel from the state cadastre, applies the current Small Second Dwelling rules, tests the planning overlays that sit on the land, and computes the largest buildable rectangle left in the rear yard once setbacks and easement clearances are taken out. It then tells you which of the three standard unit sizes actually fit. Free, no signup.
The rule the checker applies
Amendment VC253, gazetted 14 December 2023, created the Small Second Dwelling provisions in the Victoria Planning Provisions. The test is conjunctive — every limb has to be satisfied for the planning-permit exemption to apply: the lot must sit in the General Residential, Neighbourhood Residential or Residential Growth Zone; it must be larger than 300 m²; the second dwelling must be 60 m² or less; there must be no more than one existing dwelling on the lot; and no overlay or restrictive covenant may be triggered. Fail any one limb and you are back in the permit system — which is a longer process, not a prohibition.
A building permit is always required, in every case, exemption or not. Setbacks come from the siting provisions of the Building Regulations 2018 — regulation 79 requires at least 1 metre from side and rear boundaries for walls up to 3.6 m in height — and are assessed against the actual lot rather than as a single flat number that applies everywhere.
The correction worth stating plainly: there is no 550–600 m² minimum lot size for a granny flat in Victoria. The only lot-size number in the scheme is 300 m², and below it a permit is required rather than the build being prohibited. The 550–600 m² figure — which we have published ourselves and which is repeated widely online — is a commercial filter for which blocks are worth buying for this strategy. Do not read it as the law.
Which overlays actually stop a build
A Heritage Overlay is the most common blocker in the inner and middle suburbs: it can require a permit for a new building in the rear yard and, on a contributory or significant property, the answer is frequently no. A Bushfire Management Overlay brings construction standards and defendable-space clearing that eat into the very part of the backyard you were going to build on. A Special Building Overlay or a Land Subject to Inundation Overlay raises floor levels and can rule out a slab-on-ground unit entirely. A Public Acquisition Overlay means part of the land is reserved for a public work. Vegetation Protection can prevent removing the one tree standing exactly where the unit fits. The checker reports which of these touch your parcel, and the rear-yard geometry it computes is what remains after setbacks and easement clearances.
Data sources and honest limits
Parcels, easements, planning overlays and address points come from Vicmap, the state's authoritative digital cadastre. Building footprints are read from Overture Maps first, falling back to the Vicmap building layer and then OpenStreetMap — no single source has complete coverage, and new estates and recent extensions are frequently missing from all three, which is why the tool lets you trace the house yourself when the outline it drew is wrong.
This is an indicative screen, not planning advice and not a feasibility report. It cannot see a restrictive covenant or a Section 173 agreement on the title, an unregistered easement, a sewer main whose real position differs from the mapped alignment, the bearing capacity of the ground, a tree protected under a local law, or what your relevant building surveyor will require on the day. A positive result means the block is worth investigating properly. It does not mean you can build.
Frequently asked questions
Can I build a granny flat on any Melbourne block?
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No, but the constraint is rarely lot size. Under the Small Second Dwelling provisions created by Amendment VC253 (gazetted 14 December 2023), a second dwelling of 60 m² or less is exempt from a planning permit where the lot is in the General, Neighbourhood or Residential Growth Zone, is larger than 300 m², carries no more than one existing dwelling, and is not caught by an overlay or a restrictive covenant. Heritage Overlays, Bushfire Management Overlays and some Design and Development Overlays reintroduce a permit requirement or block construction outright. The checker tests your specific address against the major overlays in seconds.
Is there a minimum lot size for a granny flat in Victoria?
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The only lot-size figure in the planning scheme is 300 m²: above it the Small Second Dwelling exemption can apply, below it a planning permit is required — required, not prohibited. The 550–600 m² "minimum" widely repeated online, including previously by PremiumRea, is a commercial rule of thumb about which blocks are worth buying for this strategy, not a legal requirement.
What size granny flat fits in my backyard?
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Three standard sizes are tested: a 30 m² studio (renting $340–$370/week), a 60 m² one-bedroom ($480–$500/week) and a 60 m² dual-living configuration ($650–$700/week combined). The tool computes the largest buildable rectangle in the rear yard after applying rear and side setbacks and easement clearances, then reports which of the three physically fit. A unit that only fits by sitting on an easement is flagged, not approved.
How much does a granny flat cost to build in Melbourne?
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PremiumRea offers fixed-price construction: a 30 m² studio from $110,000 + GST, a 60 m² one-bedroom from $160,000 + GST and a 60 m² dual-living configuration from $200,000 + GST, each including building permits, construction and compliance certification. A 30 m² unit letting at $380 a week returns about 18% of the build cost — but that is a return on the incremental build spend only, not a rental yield, because the denominator excludes the land and the existing house. Measured on the whole property, the 212 granny-flat additions in PremiumRea's published transaction dataset recorded a median gross yield after works of 5.79% (n=345, settled January 2023 to September 2025, DOI 10.5281/zenodo.20095886).
Do I need a planning permit for a granny flat in Victoria?
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Usually not, if the Small Second Dwelling conditions are all met: 60 m² or less, a lot larger than 300 m² in the General, Neighbourhood or Residential Growth Zone, no more than one existing dwelling, and no overlay or restrictive covenant trigger. A building permit is always required regardless. Heritage and bushfire overlays reintroduce the planning permit requirement, and the checker flags which of these apply to your block.
Is the Granny Flat Checker free?
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Yes — free with no signup. It combines public Vicmap zoning, overlay and title data with PremiumRea's Small Second Dwelling rule engine. An account is only needed if you request a full due-diligence PDF report on a specific address, because the report is emailed to you. Architectural design, permits and construction quotation are paid services.
What can this checker not tell me?
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It cannot see a restrictive covenant or a Section 173 agreement on the title, an unregistered easement, a sewer main whose real position differs from the mapped alignment, the bearing capacity of the ground, a tree protected under a local law, or what your relevant building surveyor will require on the day. It is an indicative screen: a positive result means the block is worth investigating properly, not that you can build.