Cost Of Building a Duplex in Sydney

January 27, 2023
cost of building a duplex in sydney

Key takeaways:

  • Duplex homes have many amenities and are great for those starting a family.
  • Duplex homes are also an affordable and functional option for housing.
  • Duplex construction cost in Sydney is between $700 and $2 million.

Duplex constructions in Sydney are a great investment opportunity for those looking to enter the property market. However, understanding the costs that come with the project is crucial. From the initial planning and design stages to the construction and finishing touches, the cost of building a duplex in Sydney can vary greatly.

The cost of building duplexes in Sydney is affected by factors; such as size, materials, location, and cost of labour, and the same applies to the costs of building a house in Sydney. On average, the duplex price, in terms of construction in Sydney, can range from $700,000 to $2 million or more.

It may be possible to build a home for cheap in Sydney. Let us proceed to the breakdown and variables contributing to cost.  

The cost determinants for building a duplex in Sydney

A big part of buying a property is making sure that the build suits your needs.

When you plan to construct a duplex, consider the various types of duplex buildings. Two common types of duplex homes include back and front and semi-detached duplexes.

But, some factors determine how much you will need to spend on your duplex construction.

1. Building materials and labour

The total cost of your duplex development will be impacted by the materials chosen for the project. These materials are carefully selected, and how big the duplex determine the number of materials to buy.

The cost of these materials will vary depending on your specifications and requirements. 

Additionally, factors such as skilled labour, building workers, and subcontractors also play a significant role in determining the overall construction costs.

cost of building a duplex in sydney

Furthermore, certain elements can affect the overall cost of the building process, like:

  • House features not excluding parking requirements
  • Pest and termite control
  • Environmental regulations
  • Optional extras like landscape design and fencing
  • Water and electrical systems infrastructure
  • Safety measures and provisions
  • Pollution barriers
  • Preliminary duplex designs
  • Restumping costs

2. Building contractors and designers

cost of building a duplex in sydney
Two business man professional engineer worker at the house building, happy feeling.

The cost of duplex homes can be affected by the builders and architects you hire. Individuals with industry experience and professional skill levels charge higher fees. 

Most construction contractors complete the necessary documentation. These would include the site analysis report, summarising initial plans, and reviewing and obtaining necessary permits. Moreover, they would provide ongoing guidance throughout the project.

3. Location

When considering the cost of a duplex, location plays a crucial role. Before deciding where to purchase or invest, it’s important to verify with the local council. 

They are in charge of permitting the construction of a duplex in a given area. When researching potential locations, consider factors like;

  • The level of the population in that region
  • The rental demand
  • Availability of facilities and social amenities
  • The infrastructure
  • Local council zoning

4. Land costs

Once you have selected the location, the next step is to pick a piece of land. This phase begins with conducting examinations and gathering reports to gain knowledge about the condition of the land.

It is possible to plan for costs associated with retaining walls, rock removal, demolition costs, (for any old building), and slab upgrade.

5. Duplex size

cost of building a duplex in sydney

Excluding land costs, what a duplex builder would charge for a residential building would differ from that of a two-storey duplex. 

Regardless of whom you give your building contracts to, the size of your duplex is among the physical factors that may attract unnecessary costs to your project.

6. Demolition

Demolition is a determinant in building a duplex. You may buy an existing property with strong value growth and decide to demolish it, hence, the rebuild duplex cost. The waste management report and demolition costs are additional expenses during the whole process.

Demolition can cost between $12,000 to $40,000. On the other hand, for knockdown and rebuild, you will have to spend over $500,000 to over a million.

Some other factors are necessary, and they include:

  • Hidden costs
  • Construction industry
  • Land tax
  • Work permits
  • Owner’s income
  • Population growth

The above are crucial in attracting a high rental yield to avoid costly mistakes.

Does building a duplex in Sydney have benefits?

When you compare Sydney and Melbourne, it may cost more to build in Sydney, but it has a higher potential for buyers.

cost of building a duplex in sydney

Increased income: Having two separate units in one property can provide a steady flow of rental income.

Cost-effective: Building a duplex can be more cost-effective than building two separate houses. The costs of land, services and council fees are shared between the two units.

Flexibility: A duplex allows for flexibility in terms of living arrangements. You can choose to occupy one part and rent the other or use one unit as an investment property.

Great for families: Duplexes are a great option for families who want to live close to each other but maintain separate living spaces.

Location: Sydney is a highly desirable location with a strong property market. It can provide long-term capital growth potential for duplexes.

Low-maintenance property: Duplexes are usually low-maintenance properties. This is ideal for investors looking for rental properties.

Potential for future development: Duplexes can be an ideal option for home investors. They can develop the land in the future.


So how do you feel about the cost of building a duplex in Sydney? Is it a reliable placement, or do you see it as twice the hassle? Keep yourself updated with useful tips like these by downloading our app for the full Soho experience.

Soho is your expert team in Australian real estate, offering an innovative platform for effortless property searches. With deep insights into buying, renting, and market trends, we guide you to make informed decisions, whether it's your first home or exploring new suburbs.
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