Why Melbourne Developers Are Rethinking House Extensions in 2025–26
House extensions remain one of the most practical and financially compelling strategies available to Melbourne property developers and homeowners alike. Rather than absorbing the costs and uncertainty of relocating, extending an existing dwelling allows you to unlock latent value in land you already own — particularly in Melbourne’s Eastern Suburbs, where established blocks in suburbs like Box Hill, Doncaster, Glen Waverley, and Ringwood continue to attract strong buyer demand.
What has changed significantly heading into 2025–26 is the regulatory environment surrounding extensions and residential development. Victoria’s Housing Statement: The Decade Ahead 2024–2034 has triggered a wave of planning reforms — from the Townhouse and Low-Rise Code introduced in March 2025, to the Planning Amendment (Better Decisions Made Faster) Act 2026, which received Royal Assent on 17 February 2026. For developers, these reforms may create faster approval pathways, reduced third-party objection rights, and greater certainty around outcomes.
This guide covers everything you may need to know about house extensions in Melbourne’s Eastern Suburbs — from planning permit triggers and ResCode compliance, through to cost benchmarks, design considerations, and how the latest 2025–26 reforms could affect your project timeline and feasibility.
What Counts as a House Extension?
Before diving into approvals and costs, it helps to understand how Victorian planning defines an extension. An extension is generally an addition or increase in the floor area of an existing dwelling. This could include adding a ground floor room, building a second storey, or constructing an attached structure such as a deck, pergola, patio, or verandah that forms part of the dwelling.
An alteration, by contrast, involves internal or external changes to an existing dwelling without increasing the floor area — for example, changing wall materials or modifying windows and doors. Internal rearrangements that do not increase overall floor area, building size, or the number of dwellings generally do not require a planning permit in Victoria.
Common extension types pursued by developers and homeowners in Melbourne’s Eastern Suburbs include:
- Rear ground floor extensions — connecting living areas to outdoor spaces, popular in older compartmentalised homes
- Second storey additions — maximising development potential on smaller lots without reducing private open space
- Side extensions — suited to blocks wider than 12 metres, often used to add bedrooms or a home office
- Wraparound extensions — L-shaped additions that maximise usable floor area, particularly effective on corner blocks
- Garage conversions — a lower-cost option to create additional habitable space, subject to compliance upgrades
Do You Need a Planning Permit for a House Extension in Victoria?
This is the question most developers and homeowners ask first — and the answer depends on your specific site, zone, and overlay conditions. In Victoria, a planning permit is a separate requirement from a building permit. A building permit is required for virtually all structural work and ensures compliance with the Building Act 1993 and the National Construction Code. A planning permit, issued by the Responsible Authority (typically your local council), addresses land use and development policy.
As a general guide, a planning permit may be required for a house extension if your land is affected by any of the following:
- A Heritage Overlay — extensions to heritage-listed properties or those within heritage overlay areas require additional assessment and may significantly extend approval timeframes
- A Design and Development Overlay (DDO) — common across parts of the City of Boroondara and Manningham City Council areas
- A Neighbourhood Character Overlay (NCO) — particularly relevant in established residential precincts across the City of Whitehorse and City of Monash
- A Vegetation Protection Overlay (VPO) or Significant Landscape Overlay (SLO)
- Proximity to property boundaries that triggers ResCode setback requirements
- A second or subsequent dwelling already existing on the lot
Where no overlays apply and the extension meets all ResCode standards under Clause 54 (single dwelling on a lot), a planning permit may not be required. However, SQM Architects strongly encourages developers to conduct a thorough site assessment before assuming permit exemption applies — the consequences of building without a required planning permit can be significant.
ResCode and the Townhouse and Low-Rise Code: What’s Changed in 2025
ResCode — codified under Clause 54 and Clause 55 of Victoria’s planning schemes — has long governed residential development standards including setbacks, site coverage, overlooking, overshadowing, and neighbourhood character. For house extensions involving a single dwelling on a lot, Clause 54 remains the primary assessment tool. For extensions where two or more dwellings exist on a lot, Clause 55 applies.
The most significant recent reform is the introduction of the Townhouse and Low-Rise Code via Amendment VC267, gazetted on 6 March 2025 and operative from 31 March 2025. This amendment introduced deemed to comply standards under Clause 55, creating a faster and more certain assessment pathway for townhouses and apartment buildings up to three storeys. Under the deemed to comply framework:
- If a development meets all applicable Clause 55 standards, the corresponding objectives are deemed to be met
- The Responsible Authority is not required to consider additional decision guidelines for compliant standards
- Where all applicable neighbourhood character and amenity standards are met, third-party objector appeal rights to VCAT are removed
This is a material change for developers extending dwellings on lots with multiple dwellings. Removing third-party VCAT review rights — where standards are met — may significantly reduce project risk and timeline uncertainty. Applications lodged before 6 March 2025 continue to be assessed under the previous Clause 55 provisions.
It is worth noting that a new Clause 57 has also been introduced to govern four-storey apartment standards, and the VicSmart process has been expanded to make it easier to add a second dwelling or subdivide a residential block into two lots — changes that came into effect on 16 October 2025.
Planning Permit Approval Pathways and Timeframes
Victoria’s planning system offers several assessment pathways for house extension applications, and selecting the right pathway from the outset may save weeks or months of processing time.
VicSmart — Fast-Track Applications
VicSmart is a streamlined planning permit assessment process for straightforward, lower-impact applications. Eligible applications are assessed within 10 business days. For house extensions, VicSmart may apply where the proposal is a single-storey addition, meets all setback and site coverage requirements, and does not trigger any overlay provisions. The application fee is comparatively modest. Councils including the City of Whitehorse and Knox City Council have active VicSmart programmes — contacting the relevant Responsible Authority early to confirm eligibility is advisable.
Standard Planning Applications
Standard planning permit applications are assessed within a statutory timeframe of 60 days, though complex applications — particularly those involving heritage overlays or significant neighbour notification — may take longer. Under the Consumer and Planning Legislation Amendment (Housing Statement Reform) Act 2025, which received Royal Assent on 18 March 2025, default planning permit expiry times have been extended from two years to three years to commence a use or development, and from four years to five years to complete a development. This provides developers with greater flexibility in managing project timelines.
The Planning Amendment (Better Decisions Made Faster) Act 2026
Passed by Parliament and receiving Royal Assent on 17 February 2026, this legislation represents the most significant update to Victoria’s planning system in decades. Once fully implemented — with a default commencement date of 29 October 2027 — the Act will establish three planning permit assessment streams proportionate to the risk, complexity, and potential impacts of any given application. Lower-impact applications, including many house extensions, may be processed and approved faster under this framework. Developers planning projects in 2026–27 and beyond should monitor the Department of Transport and Planning’s guidance as supporting regulations and Ministerial guidelines are developed.
Understanding Costs: What Should Developers Budget?
Extension costs in Melbourne vary considerably based on scope, finishes, structural complexity, and site conditions. The following figures are general indicative ranges only and may vary significantly depending on scope, site conditions, and market timing. They should be treated as a starting point for feasibility modelling rather than fixed quotes.
- Ground floor extension: approximately $2,800–$4,500 per square metre
- Second storey extension: approximately $3,000–$5,500 per square metre
- Small rear addition (20m²): approximately $60,000–$90,000
- Large multi-room extension: $150,000 and above
Beyond construction costs, developers should budget for planning permit application fees, building permit fees (which vary based on the estimated cost of works), architectural and engineering fees, energy efficiency assessments (NatHERS certificates are required in Victoria), and — where applicable — heritage consultant fees. In Melbourne’s Eastern Suburbs, heritage overlay areas in the City of Boroondara and parts of the City of Whitehorse may add 4–8 weeks to approval timeframes and require specialist heritage input.
SQM Architects has delivered 210+ projects across Melbourne’s Eastern Suburbs. A disciplined approach to pre-application due diligence may help reduce the risk of costly redesigns and delays.
Key Design Considerations for Eastern Suburbs Extensions
Successful extensions in Melbourne’s Eastern Suburbs require a thorough understanding of local planning scheme policies, neighbourhood character expectations, and site-specific constraints. Each of the six Eastern Suburbs councils applies its planning scheme with distinct priorities:
- City of Boroondara — character area restrictions are actively enforced; heritage overlays are widespread across Hawthorn, Camberwell, and Kew
- City of Whitehorse — neighbourhood character policies apply across many residential precincts; vegetation overlays are common in Box Hill and Nunawading
- Manningham City Council — significant landscape overlays and vegetation protection overlays affect many properties in Doncaster and Templestowe
- City of Monash — ResCode compliance is closely scrutinised; activity centre proximity may trigger additional built form controls
- Knox City Council — bushfire management overlays apply in some eastern areas; site coverage and permeability requirements are actively assessed
- Maroondah City Council — neighbourhood character and tree canopy requirements are prominent in Ringwood and Croydon precincts
From a design perspective, extensions that maintain consistency with the original dwelling in terms of roofline, materials, window proportions, and colour palette tend to perform better through the planning assessment process and may support stronger resale outcomes. Where the Townhouse and Low-Rise Code’s deemed to comply standards apply, meeting all neighbourhood character standards — including street setback, building height, side and rear setbacks, walls on boundaries, site coverage, and front fence — removes third-party objector appeal rights, which may be a significant advantage for developers seeking certainty.
Heritage Overlays: A Developer’s Checklist
Heritage overlays represent one of the most common planning complexities for house extensions across Melbourne’s Eastern Suburbs. If your site is affected by a Heritage Overlay, the following considerations apply:
- A planning permit is required for most external alterations and extensions, including works that would not otherwise require a permit
- Extensions must generally use materials and detailing that are sympathetic to the original building’s character and period
- Rooftop changes must typically maintain the original dwelling’s roof form and ridge lines
- A heritage impact statement prepared by a qualified heritage consultant may be required
- Domestic services such as air conditioning units, skylights, and solar panels may require a planning permit where a Heritage Overlay applies
- Council heritage advisors can provide pre-application guidance — engaging them early is strongly advisable
Recent Reforms: Small Second Homes and Permit Exemptions
One reform directly relevant to developers considering extensions is the removal of the planning permit requirement for small second homes (commonly referred to as granny flats) up to 60 square metres, where no Heritage Overlay, Design and Development Overlay, or Neighbourhood Character Overlay applies. A building permit is still required, and all height, setback, and overlay requirements must be met.
Similarly, the Small Lot Housing Code removes the need for a planning permit on lots less than 300 square metres where a defined set of house design and siting standards are met. Recent updates to the code include improved standards for balconies, street-facing windows, and tree canopy provision. These exemptions may create development opportunities that were previously subject to full planning permit processes — a site assessment is the most reliable way to determine whether your property qualifies.
Frequently Asked Questions
Do I always need a planning permit to extend a house in Melbourne’s Eastern Suburbs?
Not always. Whether a planning permit is required depends on your site’s zone, any applicable overlays, and the nature of the proposed works. Single-storey extensions to a single dwelling on a lot may not require a planning permit where no overlays apply and ResCode standards are met. A site assessment by a qualified architect is the most reliable way to determine your permit obligations before committing to a design.
How long does a planning permit application for a house extension typically take?
VicSmart applications for eligible extensions may be assessed within 10 business days. Standard planning permit applications have a statutory timeframe of 60 days, though heritage overlay applications or those requiring significant neighbour notification may take longer. Building permit assessment typically adds a further 2–4 weeks once planning approval is received.
What is the deemed to comply pathway and how does it benefit developers?
The deemed to comply pathway, introduced under the Townhouse and Low-Rise Code (operative from 31 March 2025), allows applications that meet all applicable Clause 55 standards to be assessed more quickly and with greater certainty. Critically, where all neighbourhood character and amenity standards are met, third-party objector appeal rights to VCAT are removed — which may significantly reduce project risk for developers extending dwellings on lots with multiple dwellings.
What documents are typically required for a house extension planning permit application?
Most applications will require scaled architectural drawings showing existing and proposed conditions, a site plan, shadow diagrams, a neighbourhood and site description, and a written statement addressing the relevant planning scheme provisions. Heritage overlay applications may additionally require a heritage impact statement. Building permit applications require architectural plans, engineering drawings for structural elements, and a NatHERS energy efficiency certificate.
How do the 2025–26 planning reforms affect permit expiry timeframes?
Under the Consumer and Planning Legislation Amendment (Housing Statement Reform) Act 2025, default planning permit expiry times have been extended. Developers now have three years (previously two years) to commence a use or development, and five years (previously four years) to complete a development. This provides greater flexibility for projects where construction timelines may be affected by market or financing conditions.
Are there any planning permit exemptions for extensions in activity centre zones?
The new Housing Choice and Transport Zone (HCTZ), introduced via Amendment VC257 in February 2025, applies to designated activity centres and well-serviced locations across Melbourne. Properties within the HCTZ may be subject to revised building height expectations and streamlined assessment processes, including deemed to comply pathways and removal of third-party notice and review rights in some circumstances. The specific controls depend on the schedule applied to the land.
What is the difference between a planning permit and a building permit for a house extension?
A planning permit is issued by the Responsible Authority (typically your local council) and addresses land use and development policy under the relevant planning scheme. A building permit is issued by a registered building surveyor and ensures your construction complies with the Building Act 1993 and the National Construction Code. Most structural extensions require a building permit; whether a planning permit is also required depends on your site conditions and the nature of the works.
Conclusion
House extensions in Melbourne’s Eastern Suburbs remain a sound strategy for developers and homeowners seeking to unlock value from existing land holdings. The 2025–26 planning reform environment — including the Townhouse and Low-Rise Code’s deemed to comply standards, expanded VicSmart pathways, extended permit expiry timeframes, and the forthcoming Planning Amendment (Better Decisions Made Faster) Act 2026 — may create meaningful opportunities for faster, more certain approvals. However, navigating these reforms effectively requires current knowledge of your site’s zone, overlays, and the specific assessment pathway that applies to your proposal.
SQM Architects has spent 15+ years working across the City of Whitehorse, City of Boroondara, Manningham City Council, City of Monash, Knox City Council, and Maroondah City Council. Having delivered 210+ projects across these councils, our team understands what it takes to move extension projects from concept to approval efficiently. To find out what may be achievable on your site, get your free 48-hour site assessment by calling (03) 9005 6588 or contacting SQM Architects directly.
This article provides general information about Victorian planning for property developers. It does not constitute professional advice. For specific guidance on your project, contact SQM Architects (ARBV Reg. No. 51498) for a complimentary site assessment.
