$80k–$400k: Melbourne Open Plan Renovation, Permits & Feasibility
An open-plan renovation in Melbourne typically costs in the low thousands per square metre, depending on finish level and how much structural work is involved. A small rear extension might cost around mid five-figures, while a larger 40 to 60 square metre project with structural changes can be substantially more expensive. The biggest swing factors are your chosen finishes, wall removal, site access, and permit requirements, so a feasibility quote and soil report before you commit are worth every dollar.
TL;DR:
Removing load-bearing walls and installing beams can add $8,000 to $15,000 per structural change, significantly impacting renovation costs.
Soil conditions and site access issues often cause project delays and budget blowouts, making soil reports essential before signing a contract.
Permits, levies, and council fees in Victoria can add thousands to the project, with asbestos removal and planning permits further increasing overall expenses.
Fixed-price contracts and staged payments help control project costs, but provisional sums and unheld contingencies remain common sources of budget overruns.
Structural and layout decisions matter more for long-term value than high-end finishes, so prioritizing core structural work is key for maximizing investment.
Table of Contents
Detailed cost bands: per square metre and sample project budgets
Primary cost drivers: structure, services, site conditions and finishes
Victorian permit and safety requirements that affect price and timing
How to budget, choose contract type and manage payments under Victorian law
Trade-level cost expectations: demolition, structural, services, finishes
Practical cost-control strategies that keep design quality high
Yorcon’s process and what to prepare before you request a quote
Detailed cost bands: per square metre and sample project budgets
Numbers help, but only when they’re grounded in the kind of project you’re actually planning. An open-plan rear extension in Melbourne generally sits in a wide band because “open plan” can mean anything from knocking through one wall to a full rear rebuild with a new kitchen, living zone and outdoor connection.
For a standard finish open-plan extension or conversion, budget for a mid-range per square metre cost that covers a reasonable kitchen, mid-range flooring and standard joinery, without high-end customisations. Mid-range finishes, where most homeowners land, tend to cost noticeably more per square metre. High-end finishes, such as engineered stone and integrated appliances, push the price higher accordingly.
Those figures echo what industry cost indicator guides for Melbourne show for renovation work more broadly, though open-plan projects that involve structural changes sit at the higher end because you’re paying for engineering, not just fit-out.
To make this concrete, here’s how three common project types translate into total budgets:
Small rear extension (10 to 20 square metres): opening up a kitchen and adding a modest living or dining zone typically lands between $100,000 and $180,000, largely depending on whether a load-bearing wall needs a structural beam.
Kitchen-to-open-plan conversion (no extension, wall removal only): removing an internal wall, relocating services and re-fitting a kitchen usually costs $80,000 to $150,000, with the spread driven by how far plumbing and electrical need to travel.
Larger extension with structural work (40 to 60 square metres): a full rear addition with new steel framing, altered roofline and a complete open-plan living space commonly runs $250,000 to $400,000.
These budgets generally include structural work, building shell, standard services and a fit-out at the finish level chosen. They usually exclude furniture, landscaping, window treatments, and specialist items like custom joinery beyond a standard allowance. If you’re weighing whether extending makes more financial sense than moving, our guide on renovating instead of relocating walks through that comparison in more depth. For a broader whole-house view, our per square metre breakdown for whole-house renovations is a useful companion to the figures above.
Primary cost drivers: structure, services, site conditions and finishes
Two quotes for what looks like the same project can differ by tens of thousands of dollars, and the reason almost always comes down to five things.
Removing a load-bearing wall is the classic open-plan cost driver. Once you take out a structural wall, you need an engineer-specified beam to carry the load, and the size and cost of that beam depends on the span and what’s sitting above it. A modest steel beam might add $8,000 to $15,000 to a project; a longer span carrying an upper storey can cost considerably more.
Relocating services is the second big one. Moving a kitchen sink, gas line or switchboard even a few metres can mean new plumbing runs, rewiring and compliance checks, and these costs add up fast in older Melbourne homes where services weren’t designed for flexibility.
Site conditions matter too. Difficult access (a narrow side passage, no crane access, a sloping block) increases labour time and equipment hire. Soil and rock issues discovered during excavation are one of the most common reasons a provisional sum blows out, which is why a soil report before you sign a contract is one of the cheapest insurance policies available.
Finishes are the most controllable factor. Joinery, appliances and benchtops can double the fit-out cost between a project’s low and high estimate, even when the structural scope is identical.
Load-bearing wall removal and beam installation
Services relocation for kitchens, bathrooms or laundries
Site access, excavation and soil conditions
Finish selections across joinery, appliances, and stone
Hidden issues like rot, termite damage, or unplanned waterproofing
Pro Tip: Ask your builder to itemise structural, services and finish costs separately in any early quote. It makes comparing two builders’ numbers far easier.
Victorian permit and safety requirements that affect price and timing
Melbourne homeowners often underestimate how much regulation shapes an open-plan renovation budget, and getting this wrong can delay a project by weeks.
In Victoria, a building permit is mandatory for any building work valued over $10,000, and a building permit levy applies above that threshold. The levy is calculated using the cost of the building work multiplied by a combined rate made up of a general levy and an additional Domestic Building Dispute Resolution Victoria (DBDRV) component, each set at 0.00064. On a mid-sized project, the levy amount is a modest cost next to the overall build but one that needs to be budgeted for alongside council fees.
Local councils publish their own minimum fees for lodging and processing a building permit application. Stonnington City Council, for example, lists minimum permit and application fees that sit on top of the levy, and most Melbourne councils follow a similar structure.
Depending on your property, a planning permit may also be required, particularly for heritage overlays, height changes or work close to a boundary. This adds both time and cost, so it’s worth checking with your council or building surveyor early rather than assuming your project is exempt.
Finally, if your home was built before the mid-1990s, asbestos is a real consideration. WorkSafe Victoria requires that asbestos be identified and safely removed before any demolition or refurbishment likely to disturb it, with licensed removalists mandated for friable asbestos and for larger non-friable jobs.
Building permits are mandatory for building work valued above the set threshold in Victoria
The levy combines a general rate and a DBDRV component, each set at a low rate per dollar of building work cost
Councils add their own minimum permit and application fees on top of the state levies
Asbestos must be identified and, where required, removed by appropriately licensed contractors under WorkSafe Victoria rules
How to budget, choose contract type and manage payments under Victorian law
Getting the contract right matters as much as getting the cost estimate right, because a well-structured contract is what protects you when the unexpected happens.
Consumer Affairs Victoria requires a major domestic building contract for any work over $10,000, and this comes with legal deposit caps: a maximum 10% deposit for contracts under $20,000, and 5% for contracts of $20,000 or more. These caps exist specifically to stop homeowners handing over large sums before any work has started.
Favour a fixed-price contract over cost-plus wherever possible. Fixed price gives you certainty on the total; cost-plus shifts risk onto you and only really suits projects where scope genuinely can’t be defined upfront.
Expect staged payments tied to construction milestones. Base, frame, lock-up, fixing and completion are the standard checkpoints, and you should only pay for work that’s actually been done.
Keep provisional sums to a minimum. These are placeholder allowances for items not yet finalised, and they’re a common source of budget blowouts if not documented tightly.
Insist on a detailed breakdown of prime cost items rather than vague allowances, so you know exactly what you’re paying for kitchen fittings, tiles or tapware.
Hold back a contingency of 10 to 15% on top of your quoted price, particularly for older Melbourne homes where hidden issues are more likely.
Our guide to prime cost versus provisional sum items goes into more detail on how these line items are best documented in a contract.
Trade-level cost expectations: demolition, structural, services, finishes
Headline budgets are useful for planning, but understanding what sits underneath them helps you read a contractor’s quote properly and spot where the money is actually going.
Demolition and disposal, particularly where asbestos-safe handling is required, typically runs a few thousand dollars for a standard open-plan wall removal, rising significantly if friable asbestos is found and licensed removal is needed. Carpentry and structural steel form one of the larger trade allowances: a standard steel beam for a modest span might cost $8,000 to $15,000 installed, while underpinning, needed when foundations can’t support new loads, can add tens of thousands more depending on depth and soil conditions.
Roofing, flashing and external joinery for a rear extension usually sit in the $15,000 to $40,000 range depending on roof complexity and material choice, colorbond steel being more affordable than tiled or zinc alternatives. Kitchen joinery is often the single biggest line item in an open-plan project: a standard kitchen fit-out might run $20,000 to $35,000, while a premium kitchen with stone benchtops and integrated appliances can reach $50,000 or more. Plumbing and electrical upgrades for a relocated kitchen typically add $10,000 to $20,000 depending on how far services need to travel.
Flooring, tiling and final finishes are where labour and product costs diverge most. Engineered timber flooring might cost $80 to $150 per square metre installed, while premium hardwood or large-format tiling pushes that higher, and it’s worth separating labour rates from product costs when comparing quotes.
Asbestos-safe demolition: from a few thousand dollars, more if licensed removal is required
Structural steel beams: roughly $8,000 to $15,000 installed
Kitchen joinery: $20,000 for standard, $50,000-plus for premium
Plumbing and electrical relocation: typically $10,000 to $20,000
Flooring and tiling: $80 to $150 per square metre for mid-range timber
For a full trade-by-trade breakdown you can use to interrogate a builder’s quote line by line, our renovation budget breakdown covers this in more detail, and our structural renovation cost guide is worth reading alongside it for the permit implications of structural changes.
Typical project timeline and what occurs at each stage
Most Melbourne homeowners underestimate how long an open-plan renovation takes from first sketch to final handover, and that gap between expectation and reality is one of the most common sources of frustration.
Design and documentation typically takes 6 to 12 weeks, depending on how many consultants are involved (architect, engineer, building surveyor) and how quickly decisions get made.
Permit lodgement and approval can take anywhere from 2 to 8 weeks through a private building surveyor, longer if a planning permit is also required.
Construction runs through base, frame, lock-up, fixing and completion stages, each triggering a progress payment, with a typical open-plan extension taking 4 to 8 months depending on scope.
Handover and defects resolution usually adds a few weeks at the end, covering final inspections and any outstanding items.
Delays are common and usually come from three sources: unexpected asbestos requiring licensed removal, soil conditions discovered during excavation, or planning objections that weren’t anticipated. Building a few extra weeks of buffer into your expectations, rather than your contract, is the sensible approach.
Practical cost-control strategies that keep design quality high
Cutting cost doesn’t have to mean cutting quality, it usually means being deliberate about where the money goes.
Standardising joinery dimensions rather than commissioning fully bespoke cabinetry can shave thousands off a kitchen fit-out without anyone noticing the difference day to day. Choosing durable mid-range finishes for high-use surfaces like benchtops and flooring, while saving on decorative items like pendant lighting or feature tiling, tends to deliver the best value per dollar. Commissioning a soil report before you get quotes is one of the cheapest ways to reduce the risk of a large provisional sum blowing out once excavation starts.
Bundling design and construction into a single design-and-build arrangement reduces the administrative back-and-forth between separate architects and builders, and can lower the risk of costly variations later. If the full scope isn’t affordable right now, phasing the work, doing the structural shell first and finishing joinery later, spreads cost over time without shrinking the eventual outcome.
Standardise joinery dimensions to avoid costly bespoke fabrication
Choose durable mid-range finishes for benchtops and flooring
Commission a soil report before finalising quotes
Bundle trades through a design-and-build arrangement
Phase the project if the full scope isn’t affordable upfront
Pro Tip: If you’re phasing works, get the structural and services scope engineered for the final layout from day one, even if you’re not building it all now. It’s far cheaper than retrofitting later.
Yorcon’s process and what to prepare before you request a quote
Some builders manage the entire building process end to end, from initial design through permits, approvals and construction, which means you work with one team rather than coordinating an architect, engineer and builder separately. Builders with extensive experience working on open-plan rear extensions to full heritage restorations note that projects that stay on budget are typically those where the brief, site conditions and finish level are locked down before construction starts.
A feasibility process run before issuing fixed-price quotes can help flag structural risks, service relocation costs and any planning overlay issues while they’re still inexpensive to address.
If you’re preparing for a feasibility call or a first quote, it helps to have a few things ready, such as a rough site plan or existing floor plan (even hand-drawn), a clear brief on the goals for the open-plan space, an indicative budget range to understand what is realistic, and any existing survey, soil report or previous permit documentation.
Getting these together before your first conversation with a builder tends to speed up the quoting process considerably, and it helps you compare quotes on equal footing.
Timing, value and where to put your money
Construction costs in Australia remain under pressure from materials and labour, a trend the Housing Industry Association has flagged even as overall renovation demand has cooled from its peak. That makes structure and layout the smarter place to spend, ahead of decorative finishes: a well-planned open-plan layout holds its value regardless of tapware trends. If you’re weighing return on spend more broadly, this comparison of renovation types and their value uplift is a useful outside reference. Our own take on renovation strategies that boost home value covers the Melbourne context directly. My practical advice: get your soil report and feasibility quote done now, decisions get more expensive to change once concrete is poured.
— Matthew
How Yorcon can help with your open-plan renovation
Once you’ve got a realistic budget in mind, the next useful step is talking to a builder who can turn it into a fixed-price plan. Yorcon offers a free project feasibility call to walk through your site, your brief and your budget before anything is locked in, which means you get a clearer picture of real costs before committing to a design.
Depending on what your project needs, we offer home extensions for open-plan additions, a full design and build service that combines architectural design with construction under one team, and specialist heritage home renovation experience for period properties where an open-plan conversion needs to respect the original character. Our home renovations service covers projects that don’t involve extending the footprint at all.
To make the most of a feasibility call, bring along:
A site plan or existing floor plan
Photos of the areas you’re looking to open up
Your rough budget range and priorities
Any existing soil reports, surveys or council correspondence
Book a free feasibility call to get a clearer picture of what your project will actually cost.
Sources
FAQ
What is the average cost of renovation per square metre in Melbourne?
An open-plan renovation in Melbourne typically costs in the low thousands per square metre, depending on finish level and how much structural work is involved. Standard finishes sit near the lower end, while premium joinery and stone benchtops push costs higher.
Is $100,000 a good budget for renovating my house?
A $100,000 budget can cover a kitchen-to-open-plan conversion or a small internal renovation without extending the footprint, but it’s tight for a rear extension with structural work. It depends heavily on whether load-bearing walls need to come out and how far services need to be relocated.
Can I renovate a bathroom for $10,000?
A $10,000 budget generally covers only cosmetic bathroom updates like tapware, painting or minor tiling repairs, not a full renovation involving new plumbing or layout changes. Any building work over $10,000 in Victoria also triggers the requirement for a building permit, which is worth factoring in even at this budget level.
How to increase home value by $50,000 in Australia?
Value uplift tends to come from improving layout and functionality, particularly open-plan living areas and kitchen upgrades, rather than purely decorative changes. Prioritising structural improvements and durable mid-range finishes over luxury fit-outs generally delivers a better return per dollar spent.
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