Should I extend up, under or out?

If you’re starting to outgrow your home but are reluctant to move away from the area you love, it might be time to consider an extension. When it comes to extending your home, there are a few options to choose from – you could build up, build under or build out. While each option has its merit, the final decision will come down to your lifestyle, your existing home and your block of land.

Keep reading to learn more about the different types of extensions and work out which option is best for your home.

Extending Up

If you don’t want to encroach on your precious backyard space, building upwards might be the right option for your home. By building an additional storey you’ll be able to double the liveable space in your home, increase your exposure to natural light and achieve stunning views of your surroundings – be it be the city skyline, ocean waves or lush bushland.

Extending up is also one of the most cost-effective ways to build, as you’ll be able to remain in the house during the build. This means you won’t have to spend money on alternative accommodation for the duration of your building project.

This option allows you to update the look and feel of your home. You could either keep the new look uniform with the original design or you could create a modern attachment which contrasts wonderfully with the existing home.

Building Under

Building under is another great solution if you don’t want to encroach on your outdoor space or if you’re constricted by a small plot of land. Building underneath comes in two forms – you’ll either excavate under your existing home and build in underneath or raise the existing home and add a new liveable area underneath.

There are many benefits to this type of extension. Particularly, in a hot country like Australia, building underneath is an excellent way to create additional rooms that will serve as a refuge from the heat come summer. A new lower level is also the perfect space to house an office or study, rumpus room, guest bedroom or multi-purpose garage.

When it comes to excavating under versus raising the existing home, excavation is generally a cheaper option, as you’ll be able to live at home during construction and you the project shouldn’t require any structural or roofing work.

This is not the case for a raise and build under, where power, water and drainage will be disrupted. This means you’ll likely have to move out of your home for at least some part of the extension and is something to keep in mind when weighing up the options.

Extending Out

If you live on a large block and don’t want to go up or down a level, building outwards might be the most suitable option for your home. Keeping your home on a single level will allow you to achieve a feeling of spaciousness and connection – particularly within your outdoor areas.


A Ground Floor Extension encompasses many options. You could build an addition including a new living area and bedrooms that extends from the existing house, or even create a new stand-alone extension connected to your existing home via a passageway. Either way, you’ll likely save money when building out, as this option rarely requires residents to vacant the home.

Need expert advice on whether you should extend up, under or out? Get in touch with the expert team at XL Built today.

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