Knockdown Rebuild
What You Need to Know Before You Demolish in South Australia & Victoria
The approval process works a little differently depending on where you're building — in South Australia this is handled through PlanSA, while in Victoria each council runs its own planning scheme.
Either way, the questions to ask before you sign are the same.
This series covers the essential things families and investors need to understand before demolishing and rebuilding.
• Whether a knockdown rebuild is the right decision — and how to weigh it up before you commit
• What needs to happen before demolition begins — approvals, asbestos, and the steps most people don't see coming
• How planning and council approvals work — and what your block actually allows before you choose a design
• The full financial picture — stamp duty, site costs, energy ratings, and the costs builders don't always include
• How to choose the right builder and understand what you're signing before the pen goes down
The series follows two parallel stories:
• The Morrison family — knocking down the family home they’ve lived in for 20 years to build something that fits their life today
• David Chen — purchasing a property specifically to demolish and rebuild as an investment
Is a Knockdown Rebuild Right for You?
The kitchen is too dark. The bedrooms are too small. The layout made sense in 1987 but it doesn’t make sense now.
For a lot of families, this is the moment the conversation starts. Not a conversation about moving — but about whether you could stay in the suburb you love, on the block you already own, and just start again.
That’s what a knockdown rebuild is. You demolish the existing home and build a brand new one in its place.
It’s becoming more common across Australia, particularly in established suburbs where land is scarce, school zones are valuable, and the thought of uprooting is simply not appealing.
But it’s also a significant undertaking. And the decision to do it — or not — is worth slowing down before you commit.
The Two Paths
Most people who end up doing a knockdown rebuild come from one of two starting points.
You already own the home
This is the Morrison family. They’ve lived in their home for twenty years. The suburb is great, the kids’ school is around the corner, and the block is generous. But the house itself has run its race.
For them, the question is whether rebuilding on their existing block makes more financial and practical sense than selling, paying stamp duty on a new purchase, and trying to find something that ticks every box in the same area.
Often, it does.
You purchase a property to demolish
This is David. He’s identified a block in an established suburb with strong long-term value. The existing home is old, poorly maintained, and not worth renovating. His intention is to purchase the property, demolish, and rebuild to either sell or hold.
For David, the decision involves a different set of financial calculations — including stamp duty on the purchase, holding costs during the build, and the tax implications of selling a newly built property.
Knockdown Rebuild vs Renovation
This is the first fork in the road, and it’s worth thinking through carefully.
Renovation can feel like the less disruptive option. But in practice, older homes have a habit of revealing problems once walls are opened — outdated wiring, asbestos, structural issues, or layouts that simply can’t be changed without major cost.
A knockdown rebuild gives you a clean slate. Modern energy efficiency standards. A layout designed for how your family actually lives. No compromises inherited from a previous owner.
It also comes with a significant period of disruption. You will need to move out for the duration — typically twelve to eighteen months in total from demolition to handover.
What Are the Costs?
Total project costs vary significantly depending on the size of the home, the suburb, and what’s involved in demolition. As a general guide for 2025–26:
• Demolition typically costs between $12,000 and $40,000, depending on the size of the existing structure and whether asbestos is present
• Construction costs generally range from $2,000 to $3,900 per square metre for standard to mid-range builds
• Add permits, design fees, site costs, and temporary accommodation, and the full project cost for most families sits well above the build contract alone
A contingency of ten to fifteen percent on top of your build cost is not cautious — it’s practical.
One Thing Worth Knowing Early
The rules around what you can demolish, what you can build, and what approvals you need differ between South Australia and Victoria. It’s not something to worry about at this stage — but it is something to be aware of as you start the process. We’ll touch on the relevant differences as they come up throughout this series.
Questions to Ask Before You Decide
• Is your block in a heritage or character area that may restrict demolition or design?
• What is the land value, and does rebuilding make financial sense compared to selling and buying elsewhere?
• How long are you prepared to be out of your home?
• Do you have a clear picture of the total cost — not just the build contract?
Clarity at this stage doesn’t slow things down. It tends to save time and money later.
Thinking about a knockdown rebuild? Before you sign a building contract, an independent review can help you understand exactly what you’re committing to.
Visit landandbuildclarity.com.au
Next in the series is Demolition: What Needs to Happen Before Anything Comes Down
Thinking about a knockdown rebuild? Before you sign a building contract, an independent review can help you understand exactly what you’re committing to. Visit landandbuildclarity.com.au
