What Factors Influence the Cost of Renovating or Extending a Home?
By Simon Pullen
One of the most common questions homeowners ask when considering a renovation or extension is, “How much will it cost?” The reality is that unfortunately there is no simple square-metre rate that applies across the board. The cost of a renovation or extension depends on numerous factors, including the existing structure and site conditions, materials, specifications, site access, and regulatory requirements. A kitchen can cost $40,000 or $200,000—it all comes down to what’s included.
At Addstyle, we take a thorough approach to cost estimation, ensuring that prospective clients receive transparent, detailed insights into the financial considerations of their renovation before any work begins. Below, we explore the key factors that influence the cost of a home renovation or extension in Perth.
The Scope & Complexity of the Project
Every renovation comes with fixed costs, including approvals, permits, insurance, and site preparation (such as protective fencing, bins, and temporary facilities). However, beyond these basics, the size and complexity of the project play a major role in determining overall costs.
- New Extensions vs. Renovations: Building a new extension generally has more predictable costs compared to working within an existing structure, where updates to older services may be required.
- Second Storey Additions vs. Ground Floor Extensions: A second storey addition requires the added costs of scaffolding and a staircase, but can be a great way to maximise space without sacrificing yard area.
- Space and Scale: Cutting costs by reducing room sizes and lowing rooflines and ceilings is false economy. Your addition must be in balance with the existing home and your room sizes should relate to what is currently there.
- Luxury vs. Standard Specifications: The quality of materials and finishes significantly impacts the budget. A well-built structure should always be the priority, as interior finishes can be upgraded over time.
- Staged Renovations: Some clients consider completing projects in stages to manage costs. While this can work, completing the work in one go is often more cost-effective due to reduced mobilisation expenses.
Materials & Finishes
The choice of materials can dramatically impact the cost of a renovation.
- Fit-Out Costs: The difference between standard and premium fixtures can be vast. For example, porcelain tiles are a cost-effective alternative to imported Italian marble but can still offer a high-end look.
- Custom vs. Prefabricated Elements: Custom cabinetry and architectural detailing add to the cost but deliver a bespoke result that enhances value.
- Craftsmanship Matters: Regardless of material choice, the expertise of tradespeople is crucial. High-quality installation makes all the difference in both appearance and durability.
- Cost-Effective Elegance: A skilled interior designer can achieve a luxury aesthetic while being selective about where to splurge and where to save.
Structural Considerations
If a renovation involves structural changes—such as removing walls or extending the foundation—costs will vary depending on the requirements.
- Heritage Homes: Older properties may require additional design elements to comply with planning regulations.
- Updating Services: Many Perth homes benefit from modernising electrical, plumbing, or insulation systems, which can improve efficiency and long-term value.
- Optimised Planning: At Addstyle, we work closely with clients to create designs that balance cost-effectiveness with architectural integrity.
Council Approvals & Regulations
Renovations must comply with local building codes and approvals, which can vary depending on location.
- Local Council & Planning Requirements: Heritage-listed or protected zones may require specific design elements and longer approval times.
- Compliance Costs: Regulations now mandate additional safety measures, such as asbestos inspection reports for home built before 2003, temporary fencing across the property and around verge trees, as well as arborist inspections.
- How Addstyle Streamlines Approvals: With over 35 years of experience navigating Perth’s planning regulations, Addstyle ensures compliance while avoiding unnecessary delays.
Labour & Trade Costs
Skilled labour is one of the largest expenses in any renovation project.
- Perth’s Labour Market: Labour costs have stabilised post-COVID but demand for trades is still very high.
- Trades That Drive Costs: Structural trades (bricklayers, carpenters, and roofers) and finishing trades (tilers, cabinet makers) have the highest impact on overall costs.
- Quality Assurance: Addstyle maintains a solid team of proven, highly skilled tradespeople to ensure workmanship that stands the test of time and reliable build programmes.
Site Conditions & Access
The site conditions of a property can influence costs.
- Limited Site Access: Narrow driveways, tight laneways, or built-up areas may require additional logistical planning.
- Sloping Blocks & Ground Conditions: If the land requires excavation or stabilisation, this may add to the project cost.
- Tailored Solutions: Addstyle provides tailored construction solutions to efficiently navigate access or terrain challenges.
Cost-Saving Tips Without Sacrificing Quality
- Prioritise Structural Quality – It’s easier to upgrade finishes later than to fix poor construction.
- Consider Alternative Materials – Well-chosen alternatives can deliver a luxury aesthetic at a lower price.
- Work with an Experienced Builder – Transparent pricing and careful project management prevent budget blowouts.
- Plan Ahead & Avoid Mid-Project Changes – Last-minute changes are costly and disruptive.
- Choose a builder with long-term financial stability – Cheap builders are unprofitable, unprofitable builders don’t last. Ensure your builder has been operating for the long term under the same entity,
Why Investing in Quality Pays Off
Choosing the cheapest builder or cutting corners on materials can lead to major problems down the track. Poor workmanship and inferior materials may lead to costly repairs, reduced home value, and ongoing maintenance headaches.
At Addstyle, we focus on long-term value. Our clients often tell us that their renovated homes feel brand new for years after completion. One example is the client who we built this home for in Mount Lawley. They initially considered a lower-cost, pre-fab renovation builder for their second storey addition, but ultimately chose Addstyle for our reputation for superior craftsmanship—Years later, their home remains a standout in the neighbourhood and we receive regular referrals from people in the area, including from real estate agents who consider it a benchmark renovation. Our client has since moved homes, and they were quick to engage Addstyle to renovate their new home too!
Final Advice & Next Steps
The best piece of advice when budgeting for a renovation is to focus on quality, plan for contingencies, and work with a builder that provides complete transparency from the outset.
If you’re considering a renovation or extension, Addstyle offers complimentary consultations to discuss your needs, budget, and design vision. Contact us today to get expert guidance tailored to your home. You can also use our Budget Indicator form and input your renovation wish list and we will contact you with a preliminary price estimate.
About the Author: Simon Pullen is a seasoned expert in home renovations and extensions, with decades of experience delivering high-quality, award-winning projects in Perth. He is the proprietor, senior design consultant and registered builder for Addstyle. Read more about this third-generation building company here.
