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How Much Does it Cost to Build a Duplex?

$550,000 - $1.3 million

    How Much Does it Cost to Build a Duplex?

    Many factors determine the final price of a duplex construction project. Architects, location, materials and land costs all heavily contribute. The average cost to build a duplex in Australia (excluding land costs) ranges between $550,000 and $1.3 million.

    Costs in Australia

    City Average Reported Costs
    Sydney $600,000 – $1.2 million
    Melbourne $650,000 – $1 million
    Canberra $550,000 – $1.1 million

    What are the Advantages of Building a Duplex?

    Strong Value Growth – Duplexes are stable investments. They can produce strong value growth with high rental yields over time, allowing you to earn more money compared to detached residential properties.

    Great for Beginners – Those who are looking to increase their net worth by investing in real estate can start by building a duplex. The cost of building a duplex is significantly lower compared to a house, which makes it less of a risk. Over time, the duplex can increase in value and can be sold for more than what it cost to build it, allowing the owner to earn a profit.

    Low Maintenance Costs – Due to the smaller size of duplexes, they often come with low maintenance costs. Some duplexes also don’t have yards or more modest exteriors, which means less money invested in the landscaping. They can also be easier to own for retirees or couples without children. The cost of the utilities each month are also more affordable due to the smaller size of the duplex.

    Affordable – Those who want to own a home but are on a tight budget can build a duplex as a more affordable option compared to building a house. Duplexes cost less compared to houses due to their smaller size. Many people who want to live closer to the city also choose to build a duplex. It provides them with the opportunity to afford a property in a specific location due to the lower cost. It also allows many people to be on the fast track to buying a home.

    Rent Out the Duplex – Duplexes are great investments because they can be rented out to a tenant or family member. The earnings can supplement the owner’s income. They can also be used to pay off the mortgage as the property increases in value and is sold for a higher amount in the coming years.

    A rendered two-storey duplex in a suburban street at dawn.

    A rendered two-storey duplex. | Source: Mai Designs Sydney

    Factors Impacting the Cost of a Duplex

    Site size – The amount of land purchased to build the duplex influences the cost, as does the location of the property. The demand for land in the area will affect the value and the price to build a duplex.

    Architects & Contractors – The types of architects and contractors who are hired affects the price of duplex homes with their rates and what they charge. Architects and contractors with a higher skill level and more experience in the industry often charge more, which can increase the duplex house cost.

    Location – The location of the site where the duplex is built is the main factor that determines the final price. Demo

    Materials – The types of materials used to construct the building will significantly influence the duplex price. Everything from the materials used on the frame to the materials installed for the countertops will determine the duplex cost.

    A modern duplex with a driveway splitting each residence.

    A modern duplex. | Source: KDAS Projects Pty Ltd

    Price Estimate for a Knockdown Rebuild

    Demolition costs depend on the size of the building and where it’s located. A standard knock down or demolition will cost between $10,000 and $30,000. As mentioned, the cost to build a duplex varies between $550,000 and $1.3 million. Factoring in these costs, the knock down rebuild duplex cost will vary between $560,000 and $1.33 million. Some of the materials that are torn down can be recycled, allowing the owner of the land to recoup some of their costs before building a new duplex. Recycling the materials are often considered to be tax-deductible donations and can make it easier to discard the remains of the old building quickly.

    How to Hire a Duplex Builder

    Ask Family Members and Friends for Referrals

    • Ask people that you trust for referrals in the local area.
    • Ask about each person’s experience and if they have any complaints or issues with working with the builder.
    • Get each builder’s contact information.
    • Review the work that was performed.

    Read Online Reviews

    • Read former customers’ reviews of each builder.
    • Review the builder’s website.
    • Look for negative reviews.

    Narrow Down Your Top Three Choices

    • Obtain estimates from various builders.
    • Ask about their experience and background.
    • Review their duplex designs and prices.

    Interview the Builder

    • Meet in-person to review the builder’s professionalism.
    • Review the duplex plans and prices.
    • Discuss your vision and budget.
    • Discuss the timeframe for building the duplex.

    Licencing and Qualifications

    • Ask if the builder is licensed and insured before signing any documents.
    • Check their license with the state.
    • Research any complaints.
    • Review the number of years they have in the industry.
    • Ask for references to talk to former customers about their experience working with the builder.

    How to Save Money Hiring a Duplex Builder

    • Build during the off-season to lower the duplex building cost.
    • Ask about current or upcoming deals and promotions.
    • Build a smaller duplex with fewer amenities.
    • Hire a newer builder who is starting out in the industry.
    • Request that the duplex is built with cheaper materials to reduce the overall duplex construction cost.



    * The cost data is based on Oneflare and third-party sources

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