Planning a home extension or renovation can be exciting, but it’s easy for your project to go over budget if you’re not careful. Many Melbourne homeowners face unexpected costs and delays, turning their dream home into a stressful experience. If you’re wondering why most extensions blow the budget, and how to avoid it, here are our top tips.
Why Do Home Extensions Go Over Budget?
Poor planning and changing the design mid-project
One of the biggest reasons a home extension can blow your budget is making changes during the construction phase. Every time you start making changes, it adds extra work, delays, and costs. Sticking to a clear plan is key to staying within budget.
Unrealistic about your budget
Many homeowners set a project budget based on rough estimates without proper planning. It’s important to be realistic about your budget. Get a detailed cost plan from your builder, architect, or contractor before starting the project.
No contingency or allowance for hidden costs
Unexpected issues can come up in any home renovation, from bad weather to structural surprises or material delays. To avoid budget blowouts, always include a 10–20% contingency in your budget to cover hidden costs.
Underestimating council approvals and paperwork
Planning permits, especially in Melbourne’s local council areas, can cause delays. If you don’t allow extra time for this, it can impact your completion date and increase labour costs.
Choosing the wrong builder or poor communication
The cheapest quote isn’t always the best. A vague or incomplete quote can lead to extra charges down the line. Clear, honest communication with your builder or design professional is essential to reduce the risk of going over budget.
Tips to Avoid Budget Blowouts in Your Extension
Start early in the process with the right team
Engage your builder, architect, or design team early in the design stage. This helps with accurate pricing and ensures your dream home stays affordable to build. When your builder is involved from the start, they can flag any design choices that may end up costing more.
Get detailed quotes with prime cost and provisional sum items listed
Make sure your building contract includes all prime cost items (like taps, tiles, and appliances) and provisional sums (like site works or drainage). Understanding these terms will help you stick to your budget and avoid nasty surprises.
Stick to the design once construction starts
Changing your mind during the construction phase is one of the fastest ways to blow your budget. It causes delays, adds extra time, and increases the cost to build.
Allow for contingency and make room for allowances
Budgeting an extra 10–20% allows for changes, price increases, or extra work. This buffer will help your project stay on track even when the unexpected happens.
Be realistic and prioritise what’s most important
Ask yourself: What parts of this extension or renovation matter most? Focus your budget there. Your builder or design professional can help you find cost savings in areas that won’t impact your vision.
Understand the full cost to build, not just the headline quote
Look beyond the base estimate. A lower quote might not include important elements like project management, approvals, or finishes. Make sure your building contract includes everything.
Planning a Home Extension in Melbourne? Here’s How to Stay on Budget
Karja Builders is a trusted Melbourne custom home builder with over 15 years of experience in the building industry. Karja pride themselves on helping homeowners build their dream home, without the stress of budget blowouts. Whether you’re planning a home renovation in Ringwood or an architecturally designed extension in Melbourne or the eastern suburbs, we’re here to guide you through every stage.
From early planning and cost estimates to the final handover, we focus on clear communication, detailed planning, and quality workmanship. Our goal? To help your project stay within budget, on time, and true to your vision.
For a deeper look into preparing for a successful extension, check out our Planning Your Home Extension Guide.
Explore more about our approach and services on our Home Extensions page.
Ready to start your home extension without blowing the budget?
Contact Karja Builders today and discover how our expert team can help minimise risk and keep your project on track.