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How much do house extensions cost? | 2024 cost guide

5th Feb '24 • By Jared Jeffery

Whatever your reason for wanting a house extension, there is one component that you want to nail first. And that is budgeting for it. At the end of this cost guide you should have a clear understanding of every cost associated with a house extension. So let’s begin.

Are you thinking of getting a house extension in 2024 but want to ensure you can comfortably afford it? Well, the good news is that a house extension on the ground floor is significantly cheaper than a second-storey addition. Not only can a house extension provide more space for your family, but it can also work as a fantastic professional space, playroom and just about anything you can imagine! 

Cost of House Extensions

You can expect to pay between $2000 - $4000 per square metre, so an 80 square metre ground floor extension will cost between $164,500 to $310,000. There are a few factors that will affect your total costs, such as the quality of your inclusions and chosen construction. 

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how much does a house extension costArticle Overview:

  • The benefits of a house extension 
  • How much does a home extension cost?
  • Estimates of the average house extension
  • Additional home extension costs
  • Considerations for your budget 
  • Finding the right builder for your house extension 
  • House extension FAQs

The Benefits of a House Extension

Other than the most obvious benefit of a house extension — more space — there are a number of advantages that come with an extra addition to your home! Three of the biggest benefits are: 

  1. You don’t have to uproot your family, life and possessions to move somewhere else! 
  2. You can transform your home into exactly what you want and like. 
  3. It can be less expensive than moving to a bigger home. 

Before you say “wait a minute, surely moving would be less hassle than having construction happening inside your home,” hear us out. There are a number of processes involved with moving. Firstly, putting your beloved home on the market, which can take a long time to sell. Secondly, the actual packing and moving part (did you know moving is up there with the top three most stressful experiences of a lifetime?). We could go on and on, but we think you get the picture! 

How much does a home extension cost?

We know you're here because you want to know how much a home extension actually costs. Well, we cannot define the exact cost of your individual home extension without knowing the size, complexity of the job and chosen materials, but we can provide a rough guide. The standard cost of your house extension will typically include roofing, insulation, cladding, interior cladding, windows and doors. 

Estimates of the Average House Extension

  • 60m2 ground floor extension: $20,000 - $75,000 
  • 80m2 ground floor extension: $164,500 - $310,000 
  • Second storey extension: 50% more than ground floor 

Additional Home Extension Costs

  • Excavation work
  • Heating and air conditioning 
  • Additional costs for a bathroom 
  • Additional costs for a kitchen
  • Quality inclusions are more expensive
  • Drawing of plans or council fees
  • Having the extension furnished

Considerations For Your Budget 

Finding the Right Builder for Your House Extension 

On, you can browse through a number of professional builders within your area. As always, we strongly recommend ensuring you take a number of quotes, do your research and ask questions. 

Some questions to ask a builder may include:

  • How long will my job take?
  • Are you insured and do you hold the relevant qualifications for this job?
  • Do you have references I can check?
  • Do you have examples of similar jobs I can see? 
  • How much will this cost? 

It is also worth noting that if a builder’s quote is significantly less than the other quotes you received and sounds too good to be true, it probably is. This builder may simply be undercutting their competitors' quotes by leaving out extra costs and then adding them after work has commenced.

This is why you should always plan for every single cost and make sure it is covered in your quote. Additionally, higher quotes may not be unreasonable but rather a reflection of the builder's experience, reputation and standard of work. Investing in the best possible builder for your house extension is always recommended by the team at

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House Extension FAQs

Should I extend my current home or move?

This is a question only you can truly answer, however, we have some tips for deciding. If you love the home you're in, and have great neighbours and facilities nearby then an extension is a fantastic alternative to moving! Not only is moving extremely stressful but often more expensive and time-consuming than adding an extension to your current home. 

Do I need to move out of my home during the construction?

The simple answer is no, you do not need to move out during the construction phase of your house extension. However, we would recommend it, particularly if you only need to leave for a couple of weeks. This takes the pressure off you and the builders to ensure the work is safely and promptly carried out. 

What eco-friendly options are there for house extensions?

In order to make your house extension eco-friendly, you may wish to use recycled materials, install a water tank (if water is needed), use energy-efficient LED light bulbs and consult with your builder on what other options are available. 

Can I DIY a house extension? 

At we believe large projects like house extensions are best left to the experts. However, if you are an experienced home improvement DIYer with the right knowledge and tools for the job you may undertake the project or enlist expert help further on in the process. 

Should I hire an architect or a builder for my extension?

If you are opting for a complex design for your house extension, an architect would be the best option and then they will likely enlist a builder to carry out the construction. In most cases, builders are more than able to handle the extension process. 

When is the right time to add a home extension?

This depends on your circumstances. If you have considered all the costs and have a budget equipped to handle the task then there is really no time like the present! However, it is wise to consider your personal and work calendar and opt for a time that is less busy and more flexible to interact with builders and oversee construction.

How much does a house extension cost?

You will approximately pay between $2000 to $4000 per square metre, so an 80 square metre ground floor extension can cost between $164,500 - $310,000. There are a few factors that will affect the costs of your home extension, such as the quality of your inclusions and chosen construction.

Cost Guides

Please note that all prices mentioned are to be used as an approximate guide only and are accurate at the time of writing. These prices may differ by location and at the discretion of each business.

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