House Extensions
Thinking About a House Extension in Melbourne? Read This First
A house extension is one of the most cost-effective ways to add space without the cost and disruption of moving. But before you start drawing up plans, there are a few things every Melbourne homeowner needs to understand — including planning permits, costs, and whether your block is even suitable.
House Extension Costs in Melbourne 2026
| Extension Type | Typical Cost Range |
|---|---|
| Small rear extension (under 30m²) | $80,000 – $150,000 |
| Medium extension (30–60m²) | $150,000 – $280,000 |
| Large extension / second storey | $280,000 – $500,000+ |
| Granny flat / studio | $120,000 – $220,000 |
Do You Need a Planning Permit?
In Victoria, extensions under certain thresholds may be exempt from a planning permit — but a building permit is always required. Whether you need a planning permit depends on your council zone, the size of the extension, and your property's overlay controls (heritage, vegetation, etc.).
Most rear single-storey extensions in standard residential zones don't require a planning permit if they meet ResCode requirements. Second storeys almost always require one. We handle this process for our clients — it's part of our service.
Is Your Block Suitable?
Check your setbacks
ResCode requires minimum setbacks from side and rear boundaries. On a typical Melbourne suburban block, you'll generally need 1–2m from side boundaries and specific rear setbacks depending on the height of the proposed extension.
North-facing living
The best extensions open north-facing living areas to the garden. If your living room currently faces south, an extension is a great opportunity to flip the layout and bring in passive solar heating — which reduces energy bills long-term.
Get an extension estimate
Upload your existing floor plan and a sketch or description of what you'd like to add. We'll send a rough estimate before we visit site.
Start your estimate →Extension vs. Moving House
In Melbourne's current market, moving to a larger home typically costs $50,000–$120,000 in stamp duty alone — before agent fees, moving costs, and the premium you pay for extra space in a new property. A well-designed extension for the same budget often delivers more space, exactly where you want it, in the suburb you already love.