Renovation & Extension in Cranbourne, South-East Melbourne
Renovating an existing house is often cheaper than knocking it down and starting over, especially when the bones are good and the location is prized. The catch is that hidden costs (asbestos, dodgy wiring, sagging stumps, non-compliant plumbing) can turn a $250k renovation into a $450k one very quickly.
What to know about Cranbourne
Established south-east centre with older stock for rebuilds alongside newer estate pockets.
A mixed suburb where you will find both new-estate blocks and infill sites with older homes. The right build strategy depends heavily on which side of the suburb you land in.
Cost snapshot
Renovation & Extension build costs in Cranbourne
Base-build rate (mid-range)
$2,700 - $3,600/m²
RLB Q4 2025 — Melbourne, custom (excl. GST)
Typical added area
40–120 m²
Habitable area, indicative
Indicative build cost
$110,000 – $430,000
Base build only; excludes land, site works, fees & GST
Build timeframe
4–9 months
Design to handover
Approval pathway
8–16 weeks
Victoria planning scheme
Victoria average (ABS)
$485,292 · $1,914/m²
ABS Building Activity 2024–25, completed detached house
Indicative planning figures only — a builder's fixed-price contract is always final. Sourced from RLB Rider Digest (Q4 2025), ABS Building Activity 2024–25, Cotality Cordell CCCI.
Council rules and overlays for renovation & extension in this area
In Victoria, a new build generally needs a planning permit (where the local planning scheme requires one) and a building permit issued by a registered building surveyor. Overlays such as Bushfire Management, Heritage, Significant Landscape and Development Contributions can apply, and growth-area blocks may attract the Growth Areas Infrastructure Contribution (GAIC). Confirm current requirements with your local council and the Victorian Building Authority before finalising a design.
The 3 decisions that shape your renovation & extension in Cranbourne
Renovate or rebuild
The tipping point is usually around 60 to 70% of the rebuild cost. Once your renovation reaches that, a knockdown rebuild is usually the better outcome for the same money.
Scope creep control
Renovations are the single hardest project type to keep on scope. Every wall opened reveals another surprise. Set contingency and stick to it.
Live in or move out
Living in a renovation costs less but takes far longer and is genuinely stressful. Moving out costs rent but often shortens the build meaningfully.
Renovation & Extension FAQs for Cranbourne
When should I renovate vs knock down?▾
Roughly, if the renovation cost exceeds 60 to 70% of a rebuild cost, a knockdown is usually the smarter path. The exception is heritage or character-listed homes.
Do I need planning consent for a renovation?▾
Small internal cosmetic work rarely does. Anything structural, external or that changes the building footprint usually does. Ask your builder to confirm.
How do I control cost blow-outs?▾
Get a detailed pre-construction survey (moisture, termite, structural, electrical), set a 15 to 20% contingency, and freeze the scope before contract signing.
Can I live in the house during renovation?▾
For smaller renovations yes, but expect the project to run 30 to 50% longer. For full-house work, moving out is usually cheaper overall.
What about heritage listing?▾
Heritage-listed homes require heritage consent as well as normal planning consent. Speak to a heritage-experienced architect early.