How much does an extension actually cost?


You’ve been collecting home improvement magazines and devouring design inspiration, but before you go any further and get too carried away with your plans, you need to know how much this dream reno is going to cost.

You jump onto Google and type in ‘how much does a renovation or extension cost?’ Your eyes light up as you see the descriptions of average ballpark costs or examples of sqm quotes or cost per room.

Unfortunately, it’s not that simple. In fact, this kind of ballparking is downright misleading as every build and site have their differences. For example; the land, the age and condition of the existing home, materials and fixtures choices as well as preliminary fees to name a few. A quote that doesn’t include all these variants would be incomplete and could be wildly inaccurate.

Hot tip: For a better idea on the cost, get a few different quotes to compare


Do your research and invite at least three highly-reputable builders to your place to quote. On site, they will be able to get an understanding of your existing home and the land underneath it. Then share your ideas and vision with them as well as your budget.

Remember, when the quotes come in, you need to compare apples with apples. If there is a big difference between them, you need to ask why. Are there hidden costs? What haven’t they included? Do they have the same level of experience/ reputation? It’s also important to engage with builders that have experience in your type of extension.

Hot tip: For an accurate quote upfront, invest in a concept design and cost analysis


If you have a fixed budget or need to seek financial assistance, then the best way to get an accurate upfront cost for the extension is with a concept design and cost analysis. This does have a fee associated with it, but it’s worth it for the extra peace of mind it delivers in finance approval and budget managing. The design and build teams who offer this use a rigorous process based on years of experience to prepare a comprehensive concept and building quote with no hidden surprises to greet you at the end of the build.

With a solid figure to work with, you can now approach lenders for funding

Armed with a concept design and building cost analysis, you are in the best position to seek pre-approval. While you may have a great relationship with a traditional banking institution, it’s always worth speaking to a broker as they have access to a broad range of lenders who can tailor finance based on your particular circumstances.

The other beauty about the concept design and cost analysis is your ability to go confidently into Development Approval knowing that the design you submit, you can actually afford to build.

Don’t jump on to Google. Give us a call today on 02 9907 4568 and set up a FREE consultation with our talented design and build team who’d be happy to answer your questions and get you started on an accurate cost upfront for your extension.

Leave a Comment

You must be logged in to post a comment.