how much does it cost to build a duplex and subdivide
The cost of building a duplex varies, depending on land size, what you want, and more. Image: Supplied by Metricon.
  • Costs can vary depending on customer objectives, market conditions, and more
  • Other costs you may not have considered include demolition and town planning
  • A duplex is also known as dual occupancy

Australia is known for having some of the largest homes and land plots in the world, but growing numbers are looking to downsize. Some consider selling up and moving to apartments, while others have their eyes on subdividing and building something in their own backyard.

Many will know the concept as a duplex, and of course, having three on the lot will be called a triplex. Other names include dual occupancy.

Top tips for building a duplex

  • Seek professional and financial advice,
  • Do your own research – find out if dual occupancy developments are permitted in your area,
  • Understand your local council guidelines and zoning regulations when it comes to subdividing,
  • Find the right builder – choose a builder who specialises in dual occupancy developments and can manage the process end-to-end,
  • Be flexible – you may need to modify your design or floorplan to suit your block, and meet the requirements of the council you are building in. Every block will have its opportunities and limitations, and
  • Manage your expectations – dual occupancy developments require a planning permit in addition to a building permit, so it is a more involved process than a standard KnockDown ReBuild.

Those tips were kindly provided by Metricon‘s General Manager – Sales, Drew Glascott.

How much does it cost to build a duplex?

There are many factors to take into account when considering the cost of building a duplex. Glascott told The Property Tribune that the duplex building costs can pivot around variables such as land size, customer objectives, location, market conditions, and more.

Costs are generally known early on in the subdividing process, but Glascott noted there may be other expenses to factor in too.

“Every dual occupancy project is unique, however, building costs can typically be determined before entering the town planning stage.” Other costs that may not have considered include demolition and town planning, according to Glascott.

What do you need to consider when building a duplex?

Some of the first few questions to ask include whether two homes can fit and whether it is allowed.

“You’ll need to find a block of land large enough to accommodate more than one dwelling (or have a feasibility study completed on your existing land), in an area that allows dual occupancy developments,” said Glascott.

“It is essential to understand your local council’s planning scheme and zoning rules when it comes to subdividing. Each local council has their own set of guidelines and zoning regulations, and what is possible in one LGA might not be in the next.

Drew Glascott, Metricon, General Ganager – Sales

“Additional factors that need to be considered include easements, driveway requirements, significant trees, and restrictive covenants,” added Glascott.

How long does it take to build

The time it takes to build a duplex can vary, with experts telling The Property Tribune the most time-consuming part of the process happens before the foundation is laid.

“From land acquisition to auction, a two-home dual occupancy development requires, on average, 24 months to be completed. These times frames are subject to individual circumstances,” said Glascott.

“A considerable amount of time is dedicated to the pre-construction phase, which involves planning and working with local councils. Obtaining plan endorsements from councils is mandatory, and the approval duration may vary depending on the council and the complexity of the build.”

What are the benefits of building a duplex?

In a single word: choice. Glascott told The Property Tribune that building a duplex may allow you to diversify your income streams*.

“With the flexibility of dual occupancy, you have the freedom to choose whether to live in one home, sell one, rent one or both, or even sell both homes depending on the current state of the real estate market.

“This allows you to diversify your income streams and potentially earn additional income from renting out one or both units. This is a financial consideration that should be factored into the initial stages of the development process.

“Obtaining professional advice from a financial advisor about whether your return on investment is viable is the most important step.”

Glascott also noted that, “It is essential to look for a builder who offers a structural guarantee to protect your investment.”


*This article contains general information and should at no time be considered financial advice to the reader. The reader should always verify their situation with their financial advisors before taking any further steps.

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