The construction cost will depend on whether you're doing a ground-up development or converting an existing property.

This answer is as wide as the country. While it's impossible to give a specific construction cost for building a unit, several costs affect it overall. On average, it would cost about $470,000 to construct a finished one bedroom unit.

What do I need to build a unit?

To build the unit, you need to fund the construction of the new house, planning approval and site cost estimation for the average dwelling. A builder might be your best place to start.

Construction is done in phases: excavation, foundation work, and structural work on columns, beams, and walls. For a ground-up five-story or flat block development, the construction costs per unit are between $250,000 and $300,000.

Once the excavation is done, and the foundation has been built for your building block, it's possible to construct.

What can affect my building costs?

The construction cost will depend on whether you're doing a ground-up development or converting an existing house into a step process, thereby incurring subdivision costs.

A renovation would present much lower site costs per unit, but this depends on what has to be done to turn the space into a multi-unit development. The location of the site also affects construction cost and the type of property you're looking to build according to personal objectives.

Construction in an area with development potential /high-value areas can be seen as more expensive because you have to factor in the land cost, stamp duty and renovations.

All in all, there is no simple answer. Construction costs vary based on the site you're looking to build on, its location, and how much work needs to be done to turn it into two units or apartments.

High-interest rates lead to an increase in building costs.

How long does it take to build a unit?

This depends on the type of project you're looking at and your financial situation. A ground-up build portion or volume builder can take up to 18 months, while converting an existing space into units might only take six months for a large block. Once you've started digging, it's best to factor in long lead times for construction materials and processes.

Is it cheaper to build a house or a unit?

This is also not a simple question to answer by many developers. While the two units may appear cheaper concerning land costs, other factors make it difficult to say whether building a house or unit is more cost-effective. A rough guide, construction cost can be more expensive on-site works with dedicated parking, as you need extra columns and beams to support the weight of heavy machinery that comes with excavation work. This often results in higher prices per square metre on the final price, especially when it comes to high-rise structures where you're stacking up units vertically. While building an apartment is generally seen as cheaper, it all depends on how much space needs to be excavated for there to be enough room to build. Whether you're considering building units in your own house or apartment, it's important to get in touch with a professional who can provide professional advice on your project, such as carrying out a soil test. A local architect will help map out the best planning overlays solution for you based both on your individual needs and budget/money.

What are the hidden costs of building a unit?

There are many factors to consider before you start building your unit or house.

  • Your budget

  • Site access

  • Builder's fees

  • Architect fees

  • Local council charges and planning permits as stated by the council requirements

  • Site preparation costs

  • Building insurance

Once you've calculated the cost to build plus these cost increases, don't forget that there will be numerous cost blow outs other unexpected build costs involved in your project. This might include unforeseen structural damage to the land property, for example, which is something that your local surveyor should help you avoid by conducting regular checkups on site.

What do I need to know about hiring a builder?

Choosing a builder to oversee the project can be a difficult task.

This is why it's best to work with more than one builder initially, so you can get a better idea of how the project is progressing and who your preferred option would be.

It's also important to have a clear list of expectations before allocating a project. You should consult directly with the builder about their experience in this field and any other details that you feel are pertinent to your decision-making process.

Once you've decided on a builder and set the construction costs, don't use this as an excuse not to communicate or remain involved throughout the building process. You still have every right to ask for updates, no matter how long it takes them to finish each stage of two-story house construction, as long as they're sticking to the timeframe and budget you agreed on.

What type of site do I need?

The size of your lot is one of the most important decisions in determining what kind of dwelling you can build, where it's located about other buildings, and so on.

The average size for a block of land in the greater Sydney area is 250 square metres. Even though it's possible to build something on a smaller site, you need to be aware that it will likely require additional funds to achieve this goal.

The larger your building footprint, the more difficult it becomes to fit everything within the space. For example, a duplex development should take up more space. This means you'll likely have less storage space and overall floor space than what would be available in an apartment or townhouse.

For more information on building, buying or renovating a unit, take a look at the ACT Government's handy guide. Check if any legislation applies to your area.