How Much Do House Extensions Cost? 2026 Cost Guide

Are you thinking of getting a house extension in 2026 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. 

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:

• You don’t have to uproot your family, life and possessions to move somewhere else!

• You can transform your home into exactly what you want and like.

• 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

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• 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

• Lighting costs

• Flooring costs

• Costs of furnishings

• Heating and air conditioning costs

• Interior painting costs

• Exterior painting costs

Finding the Right Builder for Your House Extension

On Service.com.au, 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 Service.com.au.

Cost Guides

• How Much Does a Second Storey Addition Cost? | Cost Guide

• How Much Does It Cost to Hire a Carpenter? | Cost Guide

• How Much Does It Cost to Hire a Builder? | Cost Guide

• How Much Does a Granny Flat Cost? | Cost Guide

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.