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House Extensions Melbourne

House extensions in Melbourne that add real space without losing your home’s character. Rear, side and second-storey. Fixed price, one team, permits handled.

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Building specialties across Melbourne

Why a house extension beats moving in Melbourne

For most families, house extensions in Melbourne are the cheaper way to end up with a bigger home. You keep the street, the school zone and the neighbours, and you get the space you actually needed.

The sums back it up. Stamp duty on a $1.5 million purchase in Victoria runs past $80,000 on its own. Add agent commission, conveyancing and removalists and you’re often $130,000 down before you’ve gained a single extra bedroom.

HRE Built designs and builds extensions that connect cleanly to the existing home rather than looking bolted on the back. We work across Melbourne on Victorian, Edwardian and post-war houses, where nearly every job comes with something in the way — a heritage overlay, a character control, reactive clay, or stumps that have quietly dropped 40mm since 1954.

We find all of that during feasibility. Not three weeks into the build when it becomes a variation and an awkward phone call.

If your place has problems an extension can’t fix, we’ll tell you at feasibility and point you towards a knockdown rebuild instead.

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Types of house extensions we build across Melbourne

Rear house extensions

The most common job we do, and usually the best value per square metre, because you’re building at ground level on a slab with reasonable access.

A rear house extension in Melbourne opens the back of the home into a single kitchen, living and dining space, turns it north where the block allows, and connects it to the garden. On a single-fronted terrace it turns a dark, chopped-up floor plan into something that works for a family. Most run 30 to 60 square metres.

Second-storey extensions

For blocks with nowhere left to spread out. Narrow inner-city allotments, or homes where a ground-floor addition would swallow the whole backyard.

A second-storey extension is more involved than it looks from the footpath. The existing footings and frame have to carry the new load, which usually means underpinning and structural work downstairs in rooms you had no intention of touching. The roof comes off, so you’re likely moving out for part of the build.

The payoff is keeping every square metre of garden — on a 400 square metre block in Hawthorn or Northcote, that’s usually what decides it.

Side and wrap-around extensions

Common on Victorian and Edwardian homes with a generous side setback. A side house extension in Melbourne adds a bedroom, ensuite or study without touching the rear garden. How far you can go is set by ResCode siting provisions and any character overlay — we check that before design starts, because there’s no point drawing something the planning scheme was never going to allow.

Small and large house extensions

Not every job means taking off the back half of the house. A small house extension — pushing a kitchen out three metres, adding a proper laundry and mudroom, enclosing an unused side return — often delivers more day-to-day improvement per dollar than a big open-plan addition.

At the other end, a large house extension combining a rear addition with a second storey effectively rebuilds two-thirds of the house. Both are worth quoting properly, and the process is the same either way.

House extension costs in Melbourne

A ground-floor rear house extension in Melbourne typically costs 3,200–4,800 per square metre, and a second-storey extension 3,800–5,800 per square metre. For most homes that puts a 40 square metre rear extension between $130,000 and $195,000, and a typical second-storey addition between $280,000 and $480,000.

Two houses on the same street in Camberwell, both weatherboard, both wanting 40 square metres out the back, can come in $60,000 apart. One has a side gate you can get a bobcat through. The other has a 900mm path and a heritage overlay. That’s why we won’t quote over the phone.

For a full breakdown, read our guide to what a house extension costs in Melbourne.

Extension type	Typical size	Indicative range
Side extension (bedroom, ensuite)	15–25m²	$70,000 – $130,000
Rear extension (kitchen, living)	30–50m²	$110,000 – $220,000
Second-storey extension	60–90m²	$280,000 – $480,000
Rear extension plus second storey	90–130m²	$420,000 – $700,000+

What drives house extension costs in Melbourne

Site access

The most underrated cost driver in Melbourne. A rear laneway or a side gate wide enough for a mini-excavator saves real money. If every cubic metre of spoil goes through the hallway and every steel beam gets craned over the roof, you’re paying for a crane day a wider block wouldn’t need.

Soil class

Much of Melbourne sits on reactive clay, classified M, H1 or H2 under AS 2870. It swells and shrinks seasonally, which means deeper footings or a stiffer slab. The gap between a Class M and a Class H2 site can be $15,000 to $30,000 before anything goes up above ground. Suburbs through Doncaster and Box Hill are known for it.

The existing structure

On pre-1960s homes we routinely find stumps past their life, floor levels that have dropped, and footings that don’t go deep enough to sit alongside new ones. Normal for houses of that age — it just needs finding at feasibility so it lands in the contract price.

Planning permits

A heritage or neighbourhood character overlay adds design cost, council fees and typically three to six months before you start on site. It rarely stops a project. It shapes one.

Finish level

The structure is the structure. Finishes are where budgets quietly double. Laminate joinery and standard tapware, against custom cabinetry and stone benchtops, can differ by $40,000 to $60,000 in the same footprint. Large-format sliding or bifold doors are the other one — everybody wants them, and they’re a five-figure line item.

Build cost is not project cost. Budget separately for design, engineering, energy rating, soil report and survey; permit and council fees; temporary accommodation; landscaping; and around 10 per cent contingency.

Every quote we write is itemised down to the fixtures. Variations are documented and approved in writing before work starts. The number you sign is the number you pay.

How your house extension comes together

Stage 1 : Feasibility check

Before you spend a cent on drawings, we assess your title, planning scheme, overlays, easements, setbacks and overshadowing. If your block won’t take what you’re picturing, you’ll hear it in the first conversation — not after $12,000 of drawings.

Stage 2 : House extension design and documentation

House extension design in Melbourne happens in-house. Plans, structural engineering and energy rating prepared and lodged for your building permit. Our house extension designers work to what your block and your budget will genuinely carry, not to what looks good on a mood board.

Stage 3 : Permits and approvals

Almost every house extension in Melbourne needs a building permit. Whether you also need a planning permit depends on your council and whether your property sits in an overlay.

Building permit

Issued by a registered building surveyor, confirming the work meets the National Construction Code and the Building Regulations 2018. Many single-storey rear extensions need only this.

Planning permit

Issued by council. Triggered by a Heritage Overlay, Neighbourhood Character Overlay, Significant Landscape Overlay, or a design varying ResCode siting provisions. Boroondara, Stonnington, Bayside and Glen Eira apply these widely, which is why a house extension permit in Melbourne’s inner east takes longer than one further out.

Report and Consent

Required separately where a design varies siting rules — setbacks, site coverage, overshadowing, or overlooking a neighbour’s private open space.

Stage 4: Construction

Structural works

Underpinning, steel beams, re-stumping and roof tie-ins by licensed specialists. We design for the site class you’ve actually got.

Lock-up

Frame, roof, windows and cladding. Once it’s watertight the pace picks up noticeably.

Fit-off and finishes

Joinery, flooring, glazing, tiling and painting.

Matching the original

Skirtings, architraves and cornices matched to the existing house where it matters — which on a Victorian terrace is most places. Getting this wrong is what makes an extension read as bolted on.

Stage 5: Handover

Structural warranty pack, insurance certificates, appliance documentation and a defects period — plus a walk-through where we go room by room and write down anything you’re not happy with.

House extensions on Melbourne's period homes

Victorian and Edwardian terraces

Terraces through Fitzroy, Carlton, Northcote and Brunswick carry the strictest heritage controls in the city. The overlay generally protects the street-facing form, which is why almost every approved Victorian house extension goes to the rear, sits below the original ridgeline and is set back from the footpath. Councils want new work to read as new work rather than imitation period detail — which, done well, is the best result on these houses.

Californian bungalows and post-war homes

Through Camberwell, Glen Iris, Balwyn and Surrey Hills, the stock is generally brick with generous blocks behind, which suits rear and wrap-around additions. The usual complications are reactive clay, floor levels that have moved, and character controls dictating roof form and materials rather than heritage fabric.

How long does a house extension take in Melbourne?

Design and documentation runs eight to twelve weeks. A building permit adds two to four weeks. A planning permit adds three to six months, longer if a neighbour objects and it heads to VCAT. Construction is four to six months for a ground-floor rear extension, six to nine for a second storey.

So a straightforward house extension in Melbourne without a planning permit is realistically six to nine months start to finish. A second storey inside a heritage overlay can run fifteen to eighteen. Anyone promising materially faster is either cutting corners or hasn’t costed the approvals.

Where we build house extensions in Melbourne

We build across metropolitan Melbourne, and the work looks different depending on where you are.

01 Inner East Melbourne

larger blocks and period homes that suit second-storey additions and whole-home renovations. Hawthorn, Camberwell, Kew, Balwyn, Box Hill, Doncaster, Glen Iris and Surrey Hills.

02 Inner North Melbourne

heritage overlays, narrow blocks and Victorian terraces, where rear extensions and sympathetic renovations are our bread and butter. Brunswick, Coburg, Northcote, Preston, Fitzroy, Carlton, Thornbury and Reservoir

03 Bayside & South East Melbourne

coastal exposure calls for durable cladding and glazing, so we build for salt air and southerly weather. Brighton, Bentleigh, Sandringham, Mentone, Cheltenham, Malvern, Caulfield and Frankston.

04 West & North West Melbourne

Melbourne’s fastest-growing corridor. Mostly new custom homes and knockdown rebuilds out here, though we take on extensions to established homes in Footscray, Yarraville and Essendon.

Why choose us

Why Melbourne homeowners choose HRE Built
as their house extension builders

Building should be the least stressful part of improving your home.
These are the commitments we make on every project, residential or commercial.

Fixed price, no surprise variations

Every quote itemised down to the fixtures, with variations documented and approved in writing before a tool comes out.

One team, concept to handover

Designers, draftspeople, registered building practitioners and licensed trades under one roof. You never get handballed between a designer, a builder and a project manager.

Victorian compliance handled

NCC and Victorian building regulations, ResCode siting provisions, heritage overlays, energy ratings and AS 3740 waterproofing, documented properly the first time.

Weekly progress you can see

A dedicated site supervisor, photo updates every week and a live program.

NDIS-approved builder

SDA homes and home modifications built to the SDA Design Standard, with occupational therapist reports translated into buildable detail.

Warranty and insurance in writing

Domestic building insurance, public liability, workers’ compensation and a structural warranty pack with your keys.

Other services

Custom Home Building

New homes designed around how you actually live, built to Victorian standards with fixed pricing.

House Extensions

Ground-floor and second-storey extensions that add real space without losing your home’s character.

Kitchen Renovations

Custom Melbourne-made joinery, stone benchtops and a layout that finally works for the way you cook.

House extension FAQs

How much does a house extension cost in Melbourne?

A ground-floor rear extension typically costs $3,200 to $4,800 per square metre, a second-storey extension $3,800 to $5,800. A 40 square metre rear extension generally lands between $130,000 and $195,000. Site access, soil class and your existing footings move that figure most, which is why we quote after a feasibility check rather than over the phone.

Do I need a permit for a house extension in Melbourne?

Almost every house extension in Victoria needs a building permit. Whether you also need a planning permit depends on your council and whether your property sits in a heritage or character overlay. We check your title and overlays up front and tell you which path applies.

Can we live in the house during the extension?

Often yes for rear ground-floor additions, where we seal off the work zone and keep your kitchen or bathroom running. Second-storey extensions usually mean moving out for part of it — we plan that with you before contracts so there’s no surprise about timing or rental costs.

Is a house extension worth it in Melbourne?

For most families, yes, once you account for stamp duty, agent commission and buying costs. The honest exception is a house with problems an extension can’t fix — poor orientation, a hopeless floor plan, a busy road. We’ll say so at feasibility rather than take your deposit.

Can you extend a Victorian terrace with a heritage overlay?

Yes, regularly. Heritage overlays generally protect the street-facing form, which is why most approved extensions go to the rear, set back and visually recessive. We handle the design and the planning permit application for you.

Will I need re-stumping or underpinning?

Frequently, on Melbourne homes built before about 1960. Timber stumps have a finite life and reactive clay moves seasonally. We assess this at feasibility so it’s in the contract price rather than arriving later as a variation.

Does a house extension add value to a Melbourne home?

Generally yes, particularly a rear extension adding a fourth bedroom or opening the kitchen to the garden in an established suburb. How much depends on suburb ceiling prices and build quality. We’re builders, not valuers — talk to a local agent about your street.

What's the difference between a house extension and a renovation?

An extension adds new floor area to the footprint. A renovation reworks what you already have. Most of our projects are both, so the house flows rather than feeling like two houses stitched together.

Do you handle house extension design as well as the build?

Yes. Design, documentation, engineering, permits and construction all sit under one roof, so nobody gets to blame the drawings when something doesn’t work on site.

How do I compare house extension quotes in Melbourne?

Check whether it’s itemised, how much sits in provisional sums and prime cost items, whether domestic building insurance is included, and how variations are handled. Then check the builder’s registration on the Victorian Building Authority’s public register. Takes two minutes and it’s worth doing every time.

Start your project today

Start with a feasibility check

Before you spend money on drawings, find out what your block will actually allow. We’ll check your overlays, setbacks and site constraints and give you an honest read on what’s possible and what it’s likely to cost.