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Maintaining a home

How to plan for a home extension

27 October 2020

There’s plenty to think about when it comes to house extension planning, including:

  • budget
  • room or area
  • design
  • reason for the extension
  • how it’s going to look
  • permits, and
  • things you may want to consider if you have insurance.


According to, the average renovation in New South Wales costs between $75,000 and $150,000. Your budget will play a big part in determining whether your extension consists of something minor like some new decking, or a completely new kitchen and living area.

The big costs — like labour and materials — are obvious. But other costs can add up and can cause headaches if they’re not planned for. Think permits, fees, levies, heating and cooling, furnishings for the new area, and so on. You may also want a safety net in case expenses go beyond what you predicted (Murphy’s Law says they probably will!).

The saying ‘you have to spend money to make money’ might apply to you. For example, you may find that if you spend now to make the space energy efficient, you could increase the value of the home. It could also have the extra benefit of helping lower future power bills.

Check out our tips on how to renovate your home on a budget.

Room or area

The space you have to work with may determine how much you extend your house by.

Say you want a large outdoor kitchen and entertaining space, but you’ve only got a three by two metre garden. Could you build upwards? Or settle for something smaller? This is something to chat with your building designer or architect about.

Learn about increasing your home loan to fund renovations


You can leave it all to the pros, or work alongside them to create a beautiful design.

A tip you may often hear is to make your extension look like it belongs to your house. A postmodern, glossy black backroom may not suit your Federation home — or maybe it’s the unusual contrast you’re going for! We’ll leave that part to you.

While looks are one thing, liveability can also be as important. Building a nursery above your living area, where conversation is flowing, dishes are clattering, and the news is on, might not be the best idea, if of course, there is a better place in your space that allows for this. Large windows can make a space feel bigger, but something to think about if whether they let too much heat in during the summer months? Think about how you live and consider designing your home around that.  

Reason for the extension

Do you want to add value to your home? You’re settled in and want to improve the space? Or, you need more room for your growing family?

The purpose behind your reno may guide how much you spend, what you do, and how you do it. Discuss this with your building designer so they can help you achieve your goals.  


You’ll should dot the i's and cross the t’s before you begin work on your home extensions. Failing to get the right permits and approvals could result in a hefty fine.

You can check out these guides and checklists for your state or territory, which outline some rules for building and renovating.

Australian Capital Territory

Build, build, or renovate – approvals

New South Wales

NSW Government Fair Trading Building and renovating

Northern Territory

Building and renovating a home

South Australia

Building rules, regulations, and information


Consumer building information


Consumer Affairs Victoria’s Building and Renovating Checklist


Queensland Building and Construction Commission – Building or renovating

Western Australia

A guide to the building approvals process in Western Australia

Things you may want to consider if you have insurance

Depending on your policy, your building or home and contents insurance may not cover you for damage to the home or building as a result of the renovations. You should contact your insurer to find out about your particular policy. If you’re a Suncorp Insurance policy holder, make sure you contact us before you begin work.

Explore Suncorp Home and contents insurance options

Read more:

Insurance is issued by AAI Limited ABN 48 005 297 807 trading as Suncorp Insurance. Consider the Product Disclosure Statement before making a decision about this insurance. This advice has been prepared without taking into account your particular objectives, financial situations or needs, so you should consider whether it is appropriate for you before acting on it.