Duplex Building Costs Melbourne: Complete Pricing Guide
Thinking about building a duplex in Melbourne? As a builder in Yarraville who's completed dozens of duplex projects across the western suburbs, I get asked about costs more than anything else. Let's break down the real numbers for 2025, what drives costs, and where your money actually goes.
What Does It Cost to Build a Duplex in Melbourne?
Duplex construction costs in Melbourne for 2025 range from $2,000 to $3,800 per square metre, with total project costs typically $650,000 to $1.45 million for two three-bedroom, two-bathroom units.
Here's how it breaks down by location:
Inner West (Yarraville, Footscray, Seddon): $2,800-$3,400 per sqm
Western Suburbs (Sunshine, Altona, Spotswood): $2,600-$3,200 per sqm
Outer Western Suburbs (Werribee, Point Cook): $2,100-$2,800 per sqm
For a typical 300sqm duplex (two 3-bed units):
- Budget build: $600,000-$750,000 total
- Mid-range build: $750,000-$1,000,000 total
- Premium build: $1,000,000-$1,400,000+ total
These are construction costs only. Total development costs include land, demolition, professional fees, council charges, and holding costs.
What Drives Duplex Construction Costs?
Location and Council Requirements
Building in Yarraville costs about 15% more than Werribee due to labour availability and tighter sites. Maribyrnong Council has different requirements than Hobsons Bay or Wyndham – infrastructure levies, design guidelines, and planning fees all vary.
Site Conditions
Demolition: $12,000-$40,000 (more if asbestos present)
Site preparation: $15,000-$50,000 for sloping blocks or poor soil
Rock breaking: $15,000-$30,000 (common in Footscray/Maribyrnong areas)
For challenging sites, see our guide to sloping block builds in the western suburbs.
Design Configuration
Side-by-side duplexes with shared central walls are most cost-effective. Mirrored layouts allow efficient plumbing, services, and material use.
Front-and-back duplexes work on narrow blocks but cost more due to separate services and longer driveways.
Two-storey duplexes add complexity (stairs, scaffolding) but maximise smaller blocks.
Good taste is free, but unnecessarily complex designs aren't. Architectural features that add cost without value hurt returns.
Finishes and Inclusions
Budget finishes: Laminate benchtops, carpet, ceramic tiles, basic appliances
Mid-range finishes: Stone benchtops, hybrid flooring, better fixtures – adds $30,000-$60,000 per unit
Premium finishes: Premium stone, timber floors, high-end appliances – adds $50,000-$80,000 per unit
For more on multi-unit projects, read our article on multi-unit construction costs Melbourne and planning for multi-unit development.
Complete Development Cost Breakdown
Construction is one part of your total budget. Here's a realistic mid-range duplex in the western suburbs:
Cost CategoryAmountLand (western suburbs block)$700,000Demolition$25,000Professional fees (architect, planner, engineer, surveyor)$50,000Construction (two 3-bed units, 300sqm)$850,000Landscaping, driveway, fencing$60,000Council fees and service connections$45,000Finance and holding costs (12 months)$55,000Total Development Cost$1,785,000Expected Value$2,000,000-$2,200,000
Professional and Planning Costs
- Architect/designer: $15,000-$35,000
- Town planner: $8,000-$15,000
- Engineer: $5,000-$12,000
- Surveyor: $2,000-$4,000
- Energy rating: $1,500-$3,000
Total: $35,000-$70,000
Council and Statutory Costs
- Planning application: $1,500-$3,000
- Building permit: $2,000-$5,000
- Developer contributions: $5,000-$20,000 per dwelling (varies by council)
- Service connections: $8,000-$15,000 per dwelling
Total: $30,000-$65,000
Finance and Holding Costs
For a 12-month build with construction finance at 7-8%:
- Interest during construction: $35,000-$65,000
- Council rates: $3,000-$5,000
- Insurance and legal: $7,000-$12,000
Total: $45,000-$80,000
Hidden Costs That Catch People Out
Service Upgrades
Sewer, power, and gas need capacity for two dwellings. Budget $8,000-$18,000 for upgrades not obvious in initial planning.
Poor Soil and Rock
Rock breaking or soil remediation adds $15,000-$30,000 in many western suburbs blocks.
Stormwater Management
Retention systems, on-site detention, or rainwater tanks add $6,000-$12,000 per dwelling under tightened council requirements.
Retaining Walls
Any slope needs retaining. Even modest walls cost $8,000-$20,000.
Section 173 Agreements
Some councils require these legal agreements restricting future development. Legal costs: $2,000-$4,000.
How to Control Costs Without Compromising Quality
Smart Design
Mirror floor plans: Identical layouts reduce design time and construction complexity. Line up kitchens and bathrooms back-to-back.
Simple roof geometry: Gable or skillion roofs beat complex multi-valley designs.
Standard ceiling heights: 2.7m ceilings with good design feel spacious without premium costs.
Rectangular footprints: Complex shapes with multiple corners increase framing and cladding costs.
Strategic Material Selection
Invest in:
- Stone benchtops (buyers notice)
- Quality flooring (heavy wear)
- Good fixtures (longevity)
- Proper insulation (lower running costs)
Save on:
- Internal wall cladding (painted plasterboard works)
- Roof materials where not visible
- Basic internal doors
- Structural elements nobody sees
Work With Experienced Duplex Builders
Multi-unit construction requires understanding of shared services, party wall construction, acoustic requirements, and efficient sequencing.
At Infinity Built, we specialise in duplex construction across Melbourne's western suburbs. We know local councils, understand efficient design, and manage projects from concept to completion.
See our building process and view completed projects like our Spotswood multi-unit development and Yarraville townhouses.
Is Building a Duplex Worth It?
For Investors
- Dual rental income: Two properties instead of one
- Better land use: Maximise expensive Melbourne land
- Capital growth: Well-located western suburbs duplexes show strong growth
- Tax depreciation: New builds offer significant benefits
A $1.8M western suburbs duplex delivers two $1M properties generating $800-$900/week total rent.
For Owner-Occupiers
- Live in one, rent the other (offset mortgage)
- Accommodate family members
- Downsize while maintaining income
- Build now, sell one later to reduce debt
For Developers
Target 15-20% profit margins in established suburbs with strong rental demand.
Duplex Construction Timeline
Planning and design: 8-12 weeks
Council approval: 8-14 weeks
Construction: 8-12 months
Total: 12-18 months
Budget for delays from weather, materials, and council processing.
Why Choose Infinity Built?
We're a Yarraville builder specialising in custom duplex development across the western suburbs.
Local expertise: Based in Yarraville, we know the councils, soil conditions, and what works in different locations.
Transparent pricing: Fixed-price contracts with clear inclusions. No surprises.
Dual occupancy specialists: Dozens of completed duplexes across the western suburbs.
Council relationships: Years with Maribyrnong, Hobsons Bay, and western councils means efficient approvals.
For more on multi-unit construction, see our guide to building townhouses in Melbourne.
Getting Started
Every duplex is different. Your block, goals, budget, and timeline all matter.
First step: understand if your block suits duplex development and what it'll realistically cost. That needs someone who knows the western suburbs and council requirements.
Call us. We'll assess your site, discuss your goals, and provide realistic costs for your situation. No obligation, no pressure – just honest advice from a Yarraville builder who's done this plenty of times.
Good taste is free, but good advice about duplex costs is invaluable. Don't estimate from generic online figures – western suburbs blocks have specific characteristics affecting costs.
Want to know what building a duplex would cost on your block? Contact Infinity Built for realistic development costs.
Planning a duplex in Melbourne's western suburbs? Contact us at Infinity Built for honest advice. We specialise in duplex and multi-unit construction across the inner west and western suburbs.
