How much does it cost to build a duplex in Australia?

The cost to build a duplex in Australia typically ranges between $550,000 and $1.3 million, depending on multiple factors, such as the location, number of bedrooms, and more.

Duplexes are gaining favour in Australia for multiple reasons. Not only do they use land efficiently, they also offer the possibility of increased rental earnings. Often, homeowners live in one unit while renting out the other, or investors will rent out both dwellings for double the rental income.

In this duplex build cost guide, we explore:

• What is a duplex?
• What factors affect the cost of building a duplex?
• How much does it cost to build a duplex?
• Getting quotes from duplex home builders, and more.

Want to find duplex builders Sydney, Melbourne, Brisbane, Perth or Adelaide?

What is a duplex?

What is a duplex house? A duplex, also known as dual occupancy homes, is a housing structure with two separate units, sharing a central wall. Unlike apartments or townhouses with multiple units arranged vertically or horizontally, a duplex usually features two homes side by side or stacked. Each unit operates independently, with its own entrance, living space, utilities, and amenities.

You might like: How much does a house extension cost?

What factors affect duplex pricing?

How much to build a duplex? The cost of building a duplex is impacted by multiple factors. These considerations can vary based on location, market conditions, and specific project details. Here are some key factors that commonly affect duplex pricing:

• Location: The city or region where the duplex is being built significantly influences the cost. Factors such as land costs, labour rates, and local building codes can vary widely.
• Size and Design: The size of the duplex and its design complexity play a crucial role. Larger or more intricate designs may require more materials and labour, affecting overall costs, as well as whether you opt for a double or single story duplex.
• Cost of Duplex Building Materials: The choice of materials used in construction, from the foundation to finishes, can impact pricing. High-quality materials often come with a higher price tag but may result in a more durable and aesthetically appealing structure.
• Labour Costs: Labour costs, including wages for construction workers and skilled professionals, are a significant factor in duplex pricing. These costs can vary based on the local job market and demand for construction services.
• Site Preparation: The condition of the land and the extent of site preparation needed can affect duplex building costs. For instance, if extensive excavation or grading is required, it can add to the overall expenses.
• Permits and Regulations: Obtaining necessary permits and adhering to local building regulations may involve additional costs. Compliance with zoning requirements and building codes is essential and can impact the design and construction process.
• Market Conditions: The state of the construction market, including supply and demand for materials and labour, can influence the final price of duplex homes. During periods of high demand, costs may rise, while economic downturns may lead to more competitive pricing.

While duplex construction cost will be affected by these factors, for an accurate estimate it’s best to get in touch with local duplex home builders, architects or real estate experts. You can peruse various duplex home designs, request prices and compare quotes.

You might like: How much is Lenders Mortgage Insurance?

How much does a duplex cost to build?

How much does it cost to build a duplex? Excluding land costs, the average cost of building a duplex ranges between $550,000 and $1.3 million, depending on the factors listed above. Typically, the cost to build a dwelling in Australia is anywhere between $1,300 and $3,900 per square metre.

Keep in mind, the purchase costs of land and any demolition work required will also need to be factored into your total project cost.

You might like: How much does it cost to build a house?

Cost of building a duplex in different Australian cities

The cost to build a duplex varies across Australian cities, based on factors such as the city’s location, the size and design of the duplex, the quality of materials used, and the specific features included in the construction. Cities with a high cost of living often attract higher labour rates.

Let’s look at duplex price list estimates for different popular Australian cities:

Duplex cost to build – Sydney

• $600,000 to $1.2 million

Cost to build duplex – Melbourne

• $650,000 to $1 million

Cost of building a duplex – Canberra

• $550,000 to $1.1 million

Duplex build cost – Brisbane

According to Livit Constructions, the cost to build a duplex in Brisbane is much cheaper than the other capital cities listed above. This may be due to the cost of living and land prices. Their data from 2022 shows that the cost of building a duplex ranges between $340,000 to $700,000 in Queensland.

Obtaining multiple quotes and conducting thorough research will help you make more informed decisions regarding the cost of building a duplex in a specific Australian city.

Want to find a duplex builder in Sydney, Melbourne, Brisbane, Perth or Adelaide?

Demolition costs for a knockdown rebuild

Demolition expenses vary based on the building’s size and location, usually ranging between $10,000 and $30,000 for a standard knockdown or demolition.

By recycling materials from the demolition, you can recover some of the costs before putting up a new duplex. Interestingly, this recycling effort is often seen as a tax-deductible donation, making disposal of the old building’s remnants a quicker process.

You might like: How much does house demolition cost?

Finding duplex designs and prices

Duplex designs and prices vary widely based on factors such as location, size, design, and the quality of materials used. There are several different ways to find quality duplex designs and prices, including:

1. Architects and Designers: Consider consulting with architects or designers who specialise in residential construction. They can create customised duplex designs tailored to your preferences, needs, and the local building regulations.

2. Building Companies: Many building companies offer pre-designed duplex plans that you can choose from. These plans often come with a range of prices based on factors like the size of the duplex and the included features.

3. Online Platforms: Explore online platforms that offer pre-designed house plans, including duplex plans. Some websites provide a variety of designs with associated estimated building costs.

4. Local Builders and Contractors: Reach out to local builders and contractors in the specific area where you intend to build the duplex. They can provide you with information on typical construction costs and may have existing duplex home designs or partnerships with designers.

5. Cost Estimation Tools: Use an online duplex building cost calculator that takes into account factors like location, size, and design preferences to provide a rough estimate of construction costs.

Keep in mind that construction costs can change, and prices for materials and labour may vary from one region to another. Additionally, local building regulations and permit costs can impact the overall expenses. For the most accurate and up-to-date information, it’s advisable to consult with professionals in the local building industry and obtain multiple quotes for your specific project.

Want to find duplex builders Sydney, Melbourne, Brisbane, Perth or Adelaide?

What are the benefits of building a duplex?

Building a duplex comes with several potential advantages:

• Cost Efficiency: Building a duplex can be more cost-effective per unit compared to constructing two separate single-family homes. Shared walls, foundations, and certain utility connections can result in cost savings.
• Rental Income: Duplexes provide the opportunity for rental income from one of the units, allowing homeowners to offset their mortgage or generate additional revenue, or to rent out both.
• Maximising Land: Duplexes make efficient use of land, enabling the construction of two separate units on a single plot. This is particularly advantageous in areas with limited available land.
• Property management: Living on-site as an owner and landlord offers the advantage of easier tenant management and building maintenance, allowing you to closely supervise the property.
• Accommodating family: Beyond financial advantages, duplexes offer non-monetary benefits. They are perfect for homeowners seeking to host family and friends, providing a level of privacy and independence. Duplex living also allows for multi-generational living without being too close for comfort. This is perfect when caring for elderly parents or planning for the future.
• Increased Property Value: Well-designed and well-maintained duplexes can potentially enhance the overall property value of the area.

It’s important to note that the feasibility and advantages of building a duplex can vary based on factors such as local zoning regulations, market demand, and individual preferences. Before deciding to build a duplex, we recommend conducting thorough research and consulting with local authorities and professionals in the field.

You might like: How much does it cost to build a granny flat?

Getting quotes from duplex home builders

Still wondering how much does it cost to build a duplex? While duplex prices do range widely, it’s best to request and compare multiple quotes from different duplex home builders in your area for an accurate representation of local market rates.

If you’re interested in building dual occupancy homes as a sound investment property, you can search our online directory to find a duplex builder near you and request quotes. Be sure to read online reviews, explore the different duplex designs and prices they offer, and ensure they have an excellent reputation.

Questions to ask:

• Are they licensed and insured?
• How much experience do they have building a duplex?
• How long will your project take to complete?
• Do they have references and a portfolio of works you can see?

It’s important to provide potential contractors with as much information as possible about your vision and job budget.

Want to find a duplex builder in Sydney, Melbourne, Brisbane, Perth or Adelaide?

*All costs and prices quoted were sourced at the time this cost guide was written and should only be used as an estimate.