How Much Do House Extensions Cost in Melbourne?

Melbourne homeowners planning extensions face a complex pricing landscape. The cost of house extensions Melbourne varies dramatically based on size, materials, and site conditions.

We at Cameron Construction see budgets ranging from $50,000 for basic ground floor additions to over $300,000 for premium double storey extensions. Understanding these cost factors helps you plan your investment wisely.

House Extension Cost Factors in Melbourne

Size and Design Complexity

Extension size directly impacts your budget. Ground floor extensions start at $2,500 per square metre, while double storey additions range from $3,500 to $5,500 per square metre due to structural requirements and scaffolding needs.

Complex designs with multiple roof lines, bay windows, or curved walls increase costs by 15-25% compared to simple rectangular additions. The Australian Bureau of Statistics reported house construction prices in Melbourne rose 0.9% this quarter, which makes size planning more critical for budget control.

Material Quality and Finish Selection

Premium materials like stone benchtops, hardwood floors, and high-end fixtures can double your extension budget compared to standard finishes. Heritage properties require materials that match existing structures (often costing 20-40% more than contemporary alternatives). Standard fixtures and fittings provide excellent value, while luxury selections dramatically increase project costs.

Site Access and Ground Conditions

Site access determines equipment costs significantly. Narrow blocks that require crane lifts or hand-carried materials add $5,000 to $15,000 to your project. Sloping sites need retaining walls and additional foundations, which increase structural costs substantially.

Poor soil conditions require deeper foundations or special engineering solutions. Rock excavation can add unexpected costs if not identified during initial site assessment (soil reports help identify these issues early).

Council Requirements and Permit Costs

Council permits range from $1,200 for basic extensions to $8,000 for complex double storey additions. Building permit levies are calculated as a percentage of the value of work for projects exceeding $10,000. Heritage overlays and neighbourhood character requirements often mandate specific materials and design elements that affect your budget.

These cost factors combine differently for each project, which leads us to examine specific extension types and their typical price ranges.

Average Extension Costs by Type

Ground floor additions represent the most cost-effective expansion option, starting at $2,500 per square metre for basic builds. A standard 40-square-metre addition costs between $100,000 and $140,000, while premium finishes push this to $180,000. The Australian Bureau of Statistics data shows Melbourne construction costs increased 1.3% this quarter, making ground floor extensions still the smartest value proposition for families who need immediate space.

Double storey extensions command premium prices due to structural complexity and scaffold requirements. Expect $3,500 to $5,500 per square metre, with a typical 60-square-metre double storey costing $210,000 to $330,000. Second storey conversions often surprise homeowners with structural upgrade costs – existing foundations rarely support additional loads without reinforcement, adding $25,000 to $50,000 to your budget.

Ground Floor Extensions Deliver Best Value

Ground floor additions provide immediate return on investment with minimal structural complications. Standard rectangular additions avoid complex engineering while they maximise usable space. The cost difference between basic and premium finishes can double your budget – choose materials strategically based on your family’s actual needs rather than aspirational desires.

Double Storey Extensions Require Premium Investment

Double storey projects justify their higher costs through substantial space gains and property value increases. Structural engineering fees alone range from $8,000 to $15,000, while scaffolding adds $12,000 to $20,000 to your project. Smart design maximises both levels simultaneously rather than treats them as separate spaces.

Kitchen Renovations Drive Value

Kitchen renovations offer the highest return on investment when homeowners plan strategically. Appliance selection drives 40% of total costs – European brands command premium prices while Australian alternatives deliver equivalent functionality (often at half the cost). Layout changes that require plumbing relocation add $8,000 to $15,000 to your budget.

Bathroom Renovations Scale Quickly

Bathroom renovations become expensive quickly when plumbing locations change. Wall removal and waterproofing updates add weeks to your timeline and thousands to your budget. Standard bathroom renovations cost $20,000 to $45,000, depending on fixture quality and layout changes. Heritage properties face additional costs for period-appropriate fixtures and council compliance.

These extension costs form just the visible portion of your total investment – several hidden expenses can significantly impact your final budget.

Hidden Costs That Increase Extension Budgets

Council Fees Beyond Basic Permits

Planning permits mark only the start of council-related expenses. Melbourne councils charge additional fees for surveyor appointments, inspection stages, and compliance certificates that add $3,000 to $8,000 to your project. Heritage overlay areas require specialist consultants for heritage impact assessments (costing $2,500 to $5,000 before construction begins). The Victorian Building Authority mandates domestic building insurance for contracts above $16,000, which adds 0.5% to 1.2% of your total project cost annually.

Structural Requirements Drive Technical Expenses

Structural engineers charge $8,000 to $20,000 for double storey extensions, with soil tests adding another $1,500 to $3,500 based on site complexity. Rock excavation discoveries can triple foundation costs unexpectedly – budgets increase by $15,000 to $40,000 when rock appears during excavation. These geological surprises occur more frequently in Melbourne’s eastern suburbs where bedrock sits closer to the surface.

Utility Upgrades Create Unexpected Expenses

Utility upgrades often surprise homeowners with electrical panel replacements that cost $3,000 to $8,000. Gas meter relocations add $2,000 to $5,000 to your budget when extensions require service repositions. Water meter upgrades for increased capacity cost $1,200 to $3,000 through Melbourne Water connections. Older homes frequently need complete electrical rewires to meet current safety standards.

Temporary Accommodation Costs Accumulate

Kitchen renovations force families into temporary arrangements for 8 to 12 weeks, with meal delivery and restaurant costs adding $200 to $400 weekly to household budgets. Bathroom renovations that require external facilities cost $150 to $300 weekly for gym memberships or alternative arrangements. Major structural work creates dust and noise that makes homes unliveable – temporary accommodation costs $1,800 to $3,500 monthly in Melbourne’s rental market. Smart homeowners budget an additional 15% to 20% above quoted prices to cover these inevitable extras that emerge during construction phases.

Final Thoughts

House extensions in Melbourne cost between $50,000 for basic ground floor additions and over $300,000 for premium double storey projects. These figures reflect current market conditions where construction costs continue to rise due to material price increases and skilled labour shortages. The cost of house extensions Melbourne varies significantly based on size, materials, and site complexity.

Detailed quotes from registered builders protect homeowners from budget surprises that can derail projects. Hidden costs such as council fees, structural upgrades, and utility connections add 15-20% to initial estimates (smart homeowners identify these expenses early rather than discover them mid-construction). Melbourne homeowners should obtain three detailed quotes, budget for contingencies, and verify builder registration through Consumer Affairs Victoria.

Professional guidance helps navigate council requirements and regulations that vary across Melbourne’s diverse suburbs. Cameron Construction specialises in home extensions and premium renovations across Melbourne. Our team handles concept to completion, from planning and permits to BCA compliance for double storey extensions, ground floor additions, and full house renovations.