How Much Does It Cost to Add a House Extension in 2023?

How Much Does It Cost to Add a House Extension in 2023?

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As Australia continues to face the COVID pandemic, homeowners are increasingly choosing to stay home to keep safe. As a result, many homeowners are deciding to extend their homes. Whether it’s a deck for safe outdoor gatherings, additional bedrooms for relatives, or a whole new level to make their home more comfortable, Watara Homes is here to help.

With Watara Homes, many Brisbane homeowners have added functionality to their homes, revolutionised their floor plans, and created whole new looks. If you’re thinking of joining them but worry about affording the cost, create a budget and cost estimate before you begin.

Budgeting for a house extension streamlines the process in many ways:

  • It prepares you for negotiations with home extension builders.
  • It helps you and your family decide what you want the most from your house extension.
  • It allows you to plan financially for your house extension while you begin the process of finding a local builder.

Use this guide as a starting point for your home remodel planning. Every home is unique, and builder estimates might differ from your calculations. To make a good home improvement budget, there’s a number of variables to consider.

With that caveat in mind, let’s explore the home extension budget and weigh the factors that influence home extension costs.

How to Plan a House Extension Budget


1. What Are Your Needs?

Discuss the purpose of the extension and how it will improve your daily life. Is it built for guests or the family? Is it meant to be functional, comfortable, or both? Who is going to use the addition, and what are they using it for?

2. What Is Your Price Range?

In most cases, it is better to decide on a number you can afford before estimating the cost. By having a number in mind, you can prevent the scope of the home extension and renovation from going beyond the amount you can pay. If your dream addition is outside that price range, you can always discuss increasing your budget later.

3. Consider Different Types of House Extensions

We will discuss the details later, but keep in mind that different house extensions have different construction costs, advantages, and drawbacks.

It is cheaper to build on the ground floor level than to add to an upper storey or to do excavation work for additional basement space. However, a ground floor extension might affect your landscaping, front porch, or other ground-level features.

Once you know what general type of house extension you want, you can calculate a first approximation of your house extension costs.

4. Consider Additional Features

If your project has additional must-have features, such as customised acoustics in a media room, wheelchair accessibility, unusual or large windows, or any other features not typically found in an addition of its type, the cost will likely be higher. 

You might be able to save money by sourcing materials for unusual features, such as reclaimed wood or unusual flooring or wall tile, on your own.

If you give your builder a clear price ceiling, they will often collaborate with you to cut costs to keep your business. If you must negotiate a price increase or give up on a feature during the project, you and your family will have already thought through your priorities.

...find a professional builder who is willing to stand by any price estimates.

Case Examples


Second-Storey Addition

Take a look at the beautiful second-floor extension on our Diane Project in Yeronga. We not only added extra second-storey living space but reorganised the first floor to suit the family’s lifestyle.

Colorbond House Extension

Colorbond is one of the leading manufacturers of steel facades and steel cladding for homes. You can view their site for more examples of Colorbond construction.

Front-of-House Extension

Blogger Contemporist featured a house in Brisbane with an intriguing front extension. The house’s architecture used the sloping grade of the land to create a stunning split-level effect.

Start Planning Your House Extension!

So, how much does it cost to add an extension to your house? Prices will vary, but make sure you consider the following factors when evaluating the budget. 

1. Prepare For the Unexpected

If you’re fortunate, your budget can accommodate all the changes you want to make to your house. If not, you might have to scale back some of the changes.

Sometimes, unforeseen problems arise during home extensions. Structural problems to the house could become known, and difficulties obtaining a building permit, inclement weather, and supply shortages can lengthen the project.

2. Find Builders You Can Trust

When evaluating proposals from home extension builders, carefully assess the record of each candidate. Does the building contractor have experience with home extensions? Do they communicate well and follow through on their agreements?

3. Compare Proposals and Estimates

If you are doing a budget renovation, there are many ways to keep costs down. However, you should always find a professional builder who is willing to stand by any price estimates.

Is their price estimate too good to be true? Are they committing to conduct the construction at a fixed price, or could the final cost increase if the builder runs into problems? Some increases for additional expenses are reasonable, but you and the builder should discuss and agree upon limits before you sign the contract.

4. Draw Up the Plans

Based on the discussion you’ve had with the home extension builders you’ve chosen, they will create detailed blueprints of the planned additions, including a floor plan. They will use them to obtain building permits before they start the construction of home extensions.

Look the plans over carefully because it might be expensive to fix problems midway through construction. If you need any information, you can learn from industry professionals at Watara Homes.

Create the Perfect Home Extension with Watara Homes

Watara Homes is a professional home improvement company with many years of experience with house extensions. We have a record of success for ground floor additions, second-storey additions, and internal renovations. Call us at (07) 3800 4665 for a free consultation.

Considering your own project?

Contact us today