Should you raise your house, or dig down?

In Brisbane many of our houses are built off the ground, making the option to achieve a second story underneath very appealing. We spoke with architect Rebekah Hurworth from Family Home Experts about which option is better.

“If your block of land is flat, you don’t want to dig down”, Rebekah explained. You’ll just create a swimming pool. There’s actually not a great price difference between raising up or digging down, so in this case it’s better to avoid the waterproofing issues and raise the house.

Timber houses, such as Queenslanders are easy to raise, however masonry houses such as brick are very hard to raise – and hard equals lots of money. In fact, unless it’s a heritage listed house, it’s generally considered cost prohibitive to raise a masonry house. So then digging down is your only option.

If you’re on a sloping block of land, sometimes it might even be a combination of the two. Remember Rebekah always prefers to raise first and pick the option that creates the least amount of waterproofing.

When it comes to how far you have to dig down or raise up, there are two controlling factors. Ceiling height is the first factor, an issue that Rebekah says is often overlooked when purchasing the house. The legal ceiling height needed for bedrooms and living spaces is 2.4 metres, and this is Australia wide. You can have a lower ceiling down to 2.1 metres in some areas such as bathrooms and corridors but it’s normally the bedrooms that control how far you have to dig down or raise up.

The second issue is the maximum height of your whole house. In Brisbane, we have height limits set by Brisbane City Council. Most houses have a height limit of 9.5 metres above ground, and this is set at the highest point of your house. The only way you can go higher than this is with a town planning approval (Development Approval) from council, and this is hard to get and costly. In Brisbane, we have a second height limit for houses on blocks of land 450sqm or below – this is called a Small Lot. These houses also have to comply with a 7.5 metre wall height limit to the outside walls along the side boundary. This is typically more controlling than the 9.5 metre height limit. So a house on 451sqm of land actually has it easier than a house on 449sqm of land.