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Planning clause references re-checked against the Victoria Planning Provisions ordinance on 31 August 2026, and every first-party figure recomputed from our published 345-transaction dataset on the same date. General information about property acquisition — not planning advice, legal advice or personal financial advice.
Joey Don · Co-Founder & CEO, PremiumRea · 2026-08-31
Across 212 Melbourne properties where we added a granny flat, the median build spend was $105,000, the median combined weekly rent after completion was $850, and the median post-build gross yield was 5.79% — compared with 5.16% for the 85 properties in the same dataset that received only a cosmetic renovation. The typical block was 651 m² and the typical purchase price $649,730. These are recorded outcomes for specific purchases settled between January 2023 and September 2025, published open-access under CC-BY 4.0 (DOI 10.5281/zenodo.20095886). They are not a forecast.
The gross yield above is the combined rent from both dwellings divided by the total capital deployed — purchase price plus works. That denominator matters. The widely quoted "18% return on a granny flat" figure is the second dwelling's rent divided by the build cost alone, which ignores the land the building sits on and is not a return any investor actually receives.
The single largest variable is not the build. It is the block. A 60 m² second dwelling is close to a commodity; a lot that can physically take one, with machine access to the rear and no easement through the buildable area, is not.
You need five facts to understand whether a Victorian block is in scope at all. Everything beyond these five is a regulatory question, and we deliberately do not answer regulatory questions here — the complete, maintained version lives on our sister company's site and is linked below.
The planning floor is 300 m². Our own acquisition filter is roughly twice that. Those two numbers answer different questions and confusing them is the most common error in published granny-flat content, including in an earlier version of our own guide.
The planning floor tells you when a permit is triggered. Our filter tells you when a build is straightforward, on budget, and rentable at a price that justifies the capital. Setbacks, site coverage, permeability, the existing house footprint and the corridor a truck or crane needs all consume land that the 300 m² figure does not account for. Below about 550 m² most Melbourne blocks still work, but the design gets constrained and the method — and therefore the price — starts to move.
Concretely, the land that gets consumed before anything is built: buildings must not occupy more than 60% of the allotment and at least 20% must remain a permeable surface (Building Regulations 2018, regs 76 and 77 — reg 77(4) expressly contemplates a lot carrying an existing dwelling and a small second dwelling); a wall up to 3.6 metres high needs at least a 1 metre side or rear setback (reg 79, Table 79); and the second dwelling must sit behind the front wall of the existing dwelling facing the frontage — that last one is a planning standard, Clause 54.02-8, not a building regulation, which is a distinction almost every published guide gets wrong.
Here is the distinction stated explicitly, because it is the thing a reader most needs and most rarely gets:
| Factor | Planning / building requirement | PremiumRea acquisition filter (commercial, not law) |
|---|---|---|
| Lot size | A permit is required below 300 m² (zone clauses 32.04-6, 32.05-7, 32.07-5, 32.08-6, 32.09-6, 32.10-4). Above 300 m² the trigger does not apply, but overlays and other clauses still can | 550–600 m² minimum in practice; the median block across our 212 builds was 651 m² |
| Side access | No planning rule on access width | A clear corridor of at least 3 m to the rear of the lot, so modules and machinery can reach the build zone |
| Second dwelling size | Gross floor area of 60 m² or less to fall inside the small second dwelling definition | We build to the 60 m² cap where the block allows it — the rent difference between 45 m² and 60 m² is larger than the cost difference |
| Easements | Consent required from the service authority to build over or near a sewer or drainage easement | An easement crossing the only buildable rear area is a decline, not a negotiation |
| Slope | No planning rule; site works are a building matter | Meaningful fall across the build zone means retaining, drainage and stumps — we price it, and it is the most common reason a cheap block is not cheap |
| Existing dwelling | One existing dwelling on the lot; the second dwelling is additional | A house whose footprint or outbuildings already occupy the rear yard usually fails even on a large block |
Across our own acquisitions, three issues account for most of the blocks we walk away from — and none of them is lot size.
Easements and water authority works. A sewer or drainage easement running through the rear yard is the single most common deal-breaker, and the most expensive to discover late. Under section 148 of the Water Act 1989 ("Structures over works") you must not, without the authority's consent, build or place fill on land over which an easement exists in favour of the authority or for water supply, sewerage or drainage — and separately, you must not build within 5 metres laterally of Melbourne Water Corporation works or 1 metre laterally of any other authority's works. Read that second limb carefully: it bites on proximity to the pipe itself, whether or not there is an easement on the title. A title search shows the easement; only a plan showing where the works physically run tells you whether a buildable area survives.
Access. If the corridor to the rear of the lot is narrower than about 3 metres, the build method changes. A modular unit that would otherwise be craned or driven in has to be built conventionally on site, or lifted over the house, and both are materially more expensive than the price list implies. This is a construction constraint, not a planning rule — a narrow block is still buildable, but the quote you were given for a wide one no longer applies.
Fall. Slope is invisible in listing photographs and expensive in practice: retaining walls, deeper footings, drainage and often a crane platform. We measure it before we make an offer rather than after, because it is the difference between the published build price and a build price that is 20–40% higher, and it is not recoverable in rent.
Our published build prices are $110K + GST for a 30 m² unit and $160K + GST for a 60 m² unit, current as at 31 August 2026. Those are product prices for the building. They are not the end-to-end cost, and any comparison that treats them as such will be wrong.
The median actual spend across the 212 granny-flat builds in our dataset was $105,000, with the middle half falling between $96,100 and $114,600. Do not read that against the product prices above as though it were the same measurement. It is a median of what 212 owners actually spent on builds settled between January 2023 and September 2025, across a mix of unit sizes and site conditions; the product prices are today's list prices for two specific units, quoted plus GST. A historical median and a current list price are different things and neither predicts the other.
What the $105,000 median does tell you is that the building is only part of the number. These are the items that sit between a product price and a finished second dwelling, in rough order of how often they bite:
The comparison that matters is not "granny flat versus nothing". It is "granny flat versus the other thing you could have done with the same money on the same house". In our dataset that comparison is available directly, because we hold both cohorts.
Across 212 granny-flat builds the median post-works gross yield was 5.79%, on a median purchase price of $649,730, a median works spend of $105,000 and a median combined weekly rent of $850. Across the 85 properties that received a cosmetic renovation only, the median post-works gross yield was 5.16%, on a median works spend of $4,500 and a median weekly rent of $650. Across all 345 transactions the median was 5.77%. All figures are medians on purchases settled between January 2023 and September 2025 and valued in November 2025.
Read that carefully, because the honest version is less dramatic than the marketing version. A granny flat moved the median gross yield by roughly 0.6 percentage points while requiring around $100,000 more capital and a construction project. It is a yield strategy that works, not a step change. What it also does — and this is harder to put a number on — is diversify the income across two tenancies, so a vacancy in one dwelling does not take the property to zero rent.
Only 14 of the 345 purchases in the dataset reached a gross yield of 8% or above. Any page implying that 8%-plus is the normal outcome of adding a second dwelling is describing the tail, not the distribution.
Source · CC-BY 4.0
Melbourne Investment Property Portfolio (2020–2026) · 345 transactions
Adding a granny flat changes four things about how the property is taxed and held. None of them is a reason on its own to build or not build, and none of the below is personal tax advice — your circumstances determine the outcome and a registered tax agent should confirm it.
Land tax. Victorian land tax is assessed on site value — the value of the land alone, as determined by the Valuer-General — not on the buildings. A new second dwelling does not directly change site value, so the immediate land tax effect is usually neutral. The indirect effect is real though: the higher rental income makes a given land tax bill easier to carry.
Vacant Residential Land Tax. This is the one people miss. VRLT applies to residential land left vacant for more than six months in the preceding calendar year, and it has applied state-wide since 1 January 2025. Two dwellings mean two occupancy positions to think about, and an unoccupied second dwelling can create an exposure the main house does not. If you build one and then leave it empty, you have added a liability rather than an income stream.
Depreciation. A newly built second dwelling is new construction, so the capital works rules apply to the building, and plant and equipment you buy new and install is not caught by the second-hand plant restriction that applies to established properties. What that is worth to you depends on your income, your ownership structure and the schedule a registered quantity surveyor prepares — we do not produce depreciation schedules and no figure should be assumed from a general page.
Capital gains tax. A second dwelling on the same title is part of the same CGT asset, since it cannot be subdivided off. If the property is or was your main residence, adding an income-producing second dwelling can affect the main residence exemption. That is a question for a registered tax agent before you build, not after you sell.
Both work, and they trade off differently rather than one being better.
An existing second dwelling is income from settlement. There is no construction risk, no delay, and no site-works surprise. Against that: it is priced into the purchase, you inherit whatever specification and condition the previous owner chose, and you inherit any compliance history — including whether the structure was ever permitted, which is worth confirming before you exchange rather than after. An unpermitted second dwelling is a real risk in this market and it is not always obvious from the listing.
Building your own means a delay of months and a construction project you have to manage or pay someone to manage. Against that: you control the specification, the layout and the finish, you know the approval history because you created it, and the cost is capital you deploy at your own timing rather than a premium embedded in the purchase price.
The decision usually comes down to which risk you would rather hold. Our own transactions include both, and the dataset does not show a clean advantage to either — which is itself a useful finding, because the marketing on both sides claims one.
The blocks cluster hard in Melbourne's south-east and outer south-east, for the unglamorous reason that this is where land parcels of 600–700 m² with usable side access are still routinely available at a price that leaves the arithmetic working. Six suburbs account for the majority of the sample.
| Suburb | Builds in dataset (n) | Median post-build gross yield |
|---|---|---|
| Cranbourne | 60 | 5.82% |
| Hampton Park | 36 | 5.83% |
| Narre Warren | 28 | 5.81% |
| Cranbourne North | 18 | 5.86% |
| Narre Warren South | 8 | 7.06% |
| Frankston | 6 | 6.70% |
The failures we see are consistent enough to list, and they are worth stating plainly because almost nobody selling granny flats does.
The block was bought before the build was tested. This is the expensive one. An offer made on the assumption that a second dwelling will fit, followed by a survey showing an easement or a fall that makes it uneconomic, leaves an investor holding an ordinary house they paid a granny-flat price for. Test the block first — that ordering is the whole value of doing this properly.
The second dwelling was built but the yard was not separated. Two households sharing one driveway, one bin area and one clothesline rents for less and turns over faster than two properly separated tenancies. The separation costs a fraction of the build and is routinely value-engineered out.
The build was specified down to hit a price. A 45 m² unit with a poor layout does not rent for much less than a well-planned 60 m², but it costs almost as much to deliver. The saving is real and the rent forgone is larger.
The builder was chosen on price alone. Construction quality on small second dwellings varies more than on volume housing, defects are the owner's problem to chase, and a cheap builder who fails mid-project is the worst outcome available on this strategy.
The rent was assumed rather than checked. Small self-contained dwellings do not rent everywhere. Before you build, confirm what comparable second dwellings in that specific suburb are actually leasing for and how long they sit vacant.
If you are comparing states, the structural difference is that Victoria sets one state-wide size definition and Queensland does not. Victoria's small second dwelling is capped at 60 m² gross floor area by Clause 73.03, state-wide. In Queensland the state defines what a secondary dwelling is, but the maximum size is set by each council's planning scheme and varies substantially between them.
That changes the investment arithmetic more than it first appears: a larger permitted second dwelling can carry a second or third bedroom, which changes the tenant pool and the achievable rent. Against that, Queensland's council-by-council variation means the answer for a specific address takes more work to establish, and our own transaction record is Victorian — we have no first-party Queensland yield data and do not publish estimates in place of it.
In our own dataset of 212 Melbourne granny-flat builds the median post-build gross yield was 5.79%, against 5.16% for the 85 properties that received only a cosmetic renovation (n=345 total, settled 2023-2025). The median build spend was $105,000 and the median combined weekly rent was $850. These are recorded outcomes for specific purchases, not a forecast, and the difference is about 0.6 percentage points of gross yield for roughly $100,000 of additional capital.
In our data the median combined weekly rent across the house and the granny flat after completion was $850, on properties bought for a median $649,730 (n=212). The second dwelling's own share depends on its size, its finish and how well the two yards are separated — a granny flat sharing a driveway and a bin area with the main house rents for less than one with its own access.
Two different numbers answer that, and they are not interchangeable. The median actual spend across our 212 builds was $105,000, with the middle half between $96,100 and $114,600 — a historical median across builds settled between January 2023 and September 2025, covering a mix of unit sizes, site works, service connections and permits. Our current published build prices are $110K + GST for 30 m² and $160K + GST for 60 m², as at 31 August 2026, and those are product prices for the building only. Budget from a written quote for your own block, not from either figure.
Generally no. Since Amendment VC253 was gazetted on 14 December 2023, a small second dwelling of 60 square metres or less does not need a planning permit on most residential lots — the permit trigger applies to lots of less than 300 square metres, and overlays can reinstate a requirement. A building permit from a registered building surveyor is always required. The complete eligibility checklist is maintained by our sister company E2ES.
The planning threshold is a lot of 300 square metres or more — below that a planning permit is triggered. In practice our own acquisition filter is much higher, around 550–600 m² minimum, and the median block across our 212 builds was 651 m². That higher figure is a commercial preference, not a legal requirement: setbacks, site coverage, the existing house footprint and machine access all consume land the 300 m² figure does not account for.
Yes. The small second dwelling provisions replaced the old dependent person's unit regime, which restricted occupancy to a dependant. The current definition in Clause 73.03 imposes no occupancy, tenure or family-relationship test, and no zone clause restricts who may lease it. What is prohibited is subdividing it onto a separate title.
No. The residential zone clauses provide that a permit must not be granted which would allow a separate lot to be created for land containing a small second dwelling. That is why a granny flat is valued as an income stream and a valuation uplift on one title, not as a second saleable asset.
In our experience the recurring deal-breakers are a sewer or drainage easement running through the only buildable area, side access narrower than about 3 metres, significant fall across the build zone, an existing house or outbuilding that already occupies the rear yard, and an overlay that reinstates a planning permit requirement. Easements are the most common and the most expensive to discover after you have exchanged.
Our operational rule is a clear corridor of at least 3 metres so that modules and machinery can reach the rear of the lot. This is a construction-method constraint, not a planning rule — a narrower block can still be built on, but the method changes to conventional on-site construction or a lift over the house, and the price changes with it.
Not without the relevant water authority's consent. Section 148 of the Water Act 1989 prohibits building or filling over land subject to a water supply, sewerage or drainage easement without the authority's consent, and separately prohibits building within 5 metres laterally of Melbourne Water Corporation works or 1 metre laterally of any other authority's works — that second limb applies whether or not an easement appears on the title. Consent for a habitable structure is discretionary and often refused. Check where the works physically run, not just what the title shows.
In our data the granny-flat cohort recorded a higher median post-works gross yield (5.79%, n=212) than the renovation-only cohort (5.16%, n=85), and lender valuations generally reflect the additional dwelling. Valuation outcomes vary by suburb and by individual valuer, and because the second dwelling cannot be sold separately it is valued as part of one asset — treat any single figure you are quoted as an example, not a rule.
Both work and they trade off differently. An existing second dwelling is income from settlement with no construction risk, but it is priced into the purchase and you inherit its specification and its approval history — confirm it was actually permitted before you exchange. Building means a delay and construction risk, but you control the specification and deploy the capital on your own timing. Our dataset contains both and does not show a clean advantage to either.
Victorian land tax is assessed on site value — the land alone — so adding a building does not directly change the assessment. The more material effect is Vacant Residential Land Tax, which has applied state-wide since 1 January 2025: each dwelling has its own occupancy position, and a second dwelling left unoccupied for more than six months can create a liability the main house does not. Confirm your own position with a registered tax agent.
A newly built second dwelling is new construction, so the capital works rules apply to the building, and plant and equipment bought new and installed is not caught by the second-hand plant restriction that affects established properties. The amount and timing depend entirely on your circumstances and on a schedule prepared by a registered quantity surveyor — we do not produce depreciation schedules and no figure should be assumed from a general page.
The timeline depends on the building surveyor, the extent of site works and the build method, and it is the number most often quoted out of date. Our sister company E2ES publishes its current end-to-end timeline for small second dwellings; use that rather than a figure from an older article, including this one.
The blocks in our dataset cluster in Melbourne's south-east: Cranbourne (n=60), Hampton Park (n=36), Narre Warren (n=28) and Cranbourne North (n=18) carry the largest sample counts, with median post-build gross yields between 5.81% and 5.86%. The spread between these suburbs is narrower than the spread within any one of them, which tells you the suburb name is not the variable — block geometry and genuine demand for a small self-contained dwelling are.
Yes, always, even where no planning permit is required. It is issued by a registered building surveyor and it is an entirely separate process from planning approval. Treat "no planning permit needed" and "no approval needed" as different statements — conflating them is the most common misunderstanding of the VC253 changes.
No. The small second dwelling provisions contemplate one second dwelling on a lot that contains one existing dwelling. A proposal for two additional dwellings is a different proposal — in planning terms it is two or more dwellings on a lot, assessed under a different clause and generally requiring a planning permit.
In our data rooming-house conversions recorded a higher median gross yield (6.94%, n=48) than granny-flat builds (5.79%, n=212). But a rooming house carries a licensing regime, prescribed minimum standards and an operational load that a granny flat does not, and the two are not comparable on gross yield alone. Higher gross yield with more compliance obligation and more management is not automatically a better investment.
Because they are dividing the second dwelling's rent by the build cost alone, ignoring the land the building sits on and the capital already deployed in the property. On that denominator almost any addition looks extraordinary. The return an investor actually receives is measured against total capital deployed — on that basis the median across our 212 builds was 5.79% gross.
Legally, 300 m² is the point at which the planning permit trigger stops applying — it is not a statement that a second dwelling fits. On a 300 m² lot the existing house, the setbacks, site coverage and permeability requirements and the access corridor will usually leave no viable build zone. The number tells you about permits, not about feasibility.
Disclaimer · Last verified · Planning clause references re-checked against the Victoria Planning Provisions ordinance on 31 August 2026, and every first-party figure recomputed from our published 345-transaction dataset on the same date. General information about property acquisition — not planning advice, legal advice or personal financial advice.
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