Mistakes to Avoid During a Knock Down Rebuild

A knock down rebuild is one of the biggest investments you'll ever make. Avoiding these common mistakes can save you thousands of dollars and months of stress.

1. Not Checking for Overlays First

Mistake: Signing a building contract before checking whether your property has heritage, environmental, or bushfire overlays.

Why it matters: Overlays can prevent demolition or restrict what you can build, potentially making your project impossible or significantly more expensive.

Solution: Check with your local council for any overlays on your property before engaging a builder.

2. Underestimating Site Costs

Mistake: Budgeting for flat-block site costs when your block is sloping, has poor soil, or requires significant earthworks.

Why it matters: Site costs can vary by $20,000–$40,000+ depending on conditions, and underestimating can blow your budget.

Solution: Get a proper soil test and site assessment before finalising your budget. Ask builders whether site costs are fixed or estimates.

3. Not Budgeting for Accommodation

Mistake: Forgetting to include rent and storage costs in the project budget.

Why it matters: You'll need alternative accommodation for 8–14 months. At $400–$800/week, that's $32,000–$112,000 in rent alone.

Solution: Include 10–14 months of rent, storage, and moving costs in your budget from the start.

4. Choosing the Cheapest Builder

Mistake: Selecting a builder based solely on the lowest price.

Why it matters: Cheap quotes often exclude site costs, demolition, or key inclusions. You may face significant extra costs during construction.

Solution: Compare what's included, not just the price. Look for fixed-price contracts and ask about exclusions.

5. Not Understanding Inclusions

Mistake: Assuming standard inclusions include items that are actually upgrades.

Why it matters: Items like ducted air conditioning, stone benchtops, or landscaping may be excluded, adding tens of thousands to your final cost.

Solution: Get a detailed inclusions list in writing. Compare builders' standard inclusions side by side on Compare My Build.

6. Ignoring Asbestos

Mistake: Not budgeting for asbestos removal if your home was built before 1990.

Why it matters: Asbestos removal adds $5,000–$15,000 to demolition costs and must be done by licensed professionals.

Solution: Get an asbestos inspection before finalising your demolition quote.

7. Making Design Changes During Construction

Mistake: Requesting layout or design changes after construction has started.

Why it matters: Variations during construction are expensive, cause delays, and can create structural issues.

Solution: Finalise every detail of your design before signing the contract. If you must make changes, get them priced before approval.

8. Not Having a Contingency Budget

Mistake: Spending your entire budget on the quoted price with no buffer.

Why it matters: Unexpected issues — rock during excavation, additional site works, or material price increases — can leave you short.

Solution: Keep a contingency of 10–15% of the total project cost for unexpected expenses.

9. Forgetting Landscaping and Driveways

Mistake: Assuming the builder's price includes landscaping, driveway, fencing, and outdoor areas.

Why it matters: These items are often excluded and can add $20,000–$50,000+ to your total project cost.

Solution: Ask specifically what's included and budget separately for landscaping, driveway, fencing, and outdoor living areas.

10. Not Checking the Builder's KDR Experience

Mistake: Choosing a builder who primarily does greenfield builds for a knock down rebuild project.

Why it matters: KDR requires specific skills — demolition management, working with existing services, and navigating established-site constraints.

Solution: Choose a builder with demonstrated knock down rebuild experience. Check their portfolio and ask for references from past KDR clients.