How Much Does It Cost to Extend a House in Brisbane

Key Takeaways

• Brisbane extensions typically cost $2,500–$4,000 per m².
• Complex or premium builds can reach $4,500–$6,000 per m².
• Always plan for hidden costs and allow a contingency buffer.
• The right local builder protects your time, budget and resale value.

Introduction

Extending your Brisbane home is one of the smartest ways to create more space, better liveability and real long-term value all without paying stamp duty and moving costs. But the big question is: how much does a Brisbane extension really cost in 2025? This guide breaks down realistic cost ranges, what drives prices up or down, real local examples, and how to plan your extension wisely.

Why Brisbane Homeowners Are Choosing to Extend

More Brisbane families are choosing to extend instead of moving. Why?

• Avoids stamp duty, agent commissions and moving stress
• Keeps you in the suburb, street and school catchment you love
• Adds modern liveability without buying new
• Boosts resale value when you eventually sell

Classic Queenslanders, post-war cottages and brick homes are especially popular for extensions whether you’re adding open-plan living, extra bedrooms or a second storey to catch breezes and views.

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How Much Does a Typical Extension Cost?

So, what should you budget for a Brisbane extension today?

In 2025, most Brisbane extensions cost between $2,500 and $4,000 per square metre for standard projects.

For example:

• Small rear room (20–30m²): $50,000–$120,000
  
• Open-plan kitchen/living (40–60m²): $120,000–$250,000
  
• Second-storey addition: $200,000–$450,000+

Important: These are broad estimates. Final costs depend on your site, design, finishes and builder. Always get a detailed, fixed-price quote for your block. If you’re planning your first big project, our Ultimate Guide to Choosing the Right Builder is worth a read.

What Drives Extension Costs in Brisbane?

Key factors that affect your budget include:

• Size & Scope: More rooms or levels naturally cost more.
  
• Structural Work: Removing load-bearing walls or underpinning footings adds engineering.
  
• Wet Areas: Bathrooms and kitchens cost more per m² due to plumbing, tiling and waterproofing.
  
• Site Access: Sloped blocks, tight sites or heritage overlays increase labour costs.
  
• Finishes: Premium materials or custom joinery lift the budget.
  
• Approvals: Brisbane City Council fees, soil tests, certifier inspections and engineering reports all add up every block has unique local rules.
• The cheapest quote isn’t always cheapest. In the end experienced builders help you avoid costly mistakes.

Real-World Example: A Brisbane Family Extension

Example:
A family in Ashgrove extended their post-war cottage with an open-plan kitchen, living area and deck around 50m².

Their actual costs:

• Design & drafting: $10,000
  
• Council & certifier: $6,000
  
• Demolition & site works: $12,000
  
• Construction: $170,000
  
• Kitchen fit-out: $35,000
  
• Contingency: $20,000
  

Total: ~$253,000

The new living space boosted their property’s resale value similar extended homes sold for $250,000–$300,000 more than comparable unrenovated houses in the same area.

Typical Cost per Square Metre Explained (2025)

Why does the cost range vary so much?

• Lower end: Simpler layouts, standard finishes, no major structural work.
  
• Higher end: Complex layouts, tight access, heritage homes or premium finishes.
  

In 2025, it’s realistic for more complex Brisbane extensions to push to $4,500–$6,000 per m² especially if you’re adding extra bathrooms, structural work or working with difficult blocks.

Always get a detailed, written quote, not just a generic estimate.

Popular Extension Types & Cost Ranges

Here’s what typical Brisbane projects look like:

Your design choices, block conditions and finishes will always affect the final cost.

What About $8,000–$10,000 per m² Quotes?

You might see stories online quoting $8,000–$10,000 per m² usually from Sydney or Melbourne. Is that normal for Brisbane?

In short, no.
These higher prices usually come from:

• Ultra-tight inner-city blocks with poor access
  
• Heritage terraces needing major structural changes
  
• High-end, architect-designed builds with imported finishes
  

In Brisbane, extensions above $6,000 per m² are rare. Most sit between $2,500–$4,000 per m², with more complex or luxury builds sometimes reaching $4,500–$6,000 per m².

Always compare quotes carefully and check exactly what’s included.

The Hidden Costs to Plan For

Extensions often reveal hidden surprises. Be ready for:

• Asbestos removal in older homes
  
• Upgrading old wiring or plumbing
  
• Temporary relocation if parts of the house are unusable
  
• Landscaping repairs after construction
  
• Design tweaks mid-build (variations)

Smart move: Always allow a 10–15% contingency buffer.

Smart Budgeting: Tips from Brisbane Builders

• Get detailed plans up front: They avoid surprises later.
  
•  Prioritise wisely: Focus your budget on what adds real value.
  
•  Use a fixed-price contract: This protects your budget.
  
•  Compare multiple quotes: Always check what’s included and what’s not.
  
• Stay involved: Good builders keep you informed at every stage.
  

DIY or Professional Builder?

DIY might seem cheaper but big extensions need licensed professionals. Missed approvals, structural problems or leaks can cost far more to fix than doing it right from the start.

A trusted Brisbane builder will:

• Manage council approvals and compliance
  
• Use reputable local trades
  
• Provide clear pricing and timelines
  
• Deliver safe, code-compliant work with warranty protection
  
• Add real resale value for the future
  

Thinking about DIY? Read Brisbane Renovation Mistakes to Avoid: Why Hiring Professionals Beats DIY Every Time — you’ll see why local expertise saves you time, money and stress.

Conclusion

A well-planned extension transforms how you live and adds real value when you sell. These figures are realistic for Brisbane in 2025 but every block, plan and approval is unique.

Your smartest move? Talk to a trusted local builder who knows Brisbane’s soil, blocks and council rules inside out.

Ready to see what’s possible? Contact Abode Construction for honest local advice and a no-obligation quote.

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