Barndominiums in Australia: What They Are and How They Get Approved

A barndominium is a steel framed building shaped like a shed. It has a simple roof, big openings and a wide clear span, meaning no posts in the middle. Inside, we finish it like a house, with insulation, lined walls and ceilings, a kitchen, a bathroom, power and plumbing.

Here in Australia it's more often called a shed home, a liveable shed or a barn home. Whatever you call it, our shed builders design it and get it approved the same way.

Most of the appeal comes from the steel frame. It goes up quickly once the slab, the concrete floor the building stands on, is poured.

On acreage, the shed shape also sits well in the landscape.

To live in a barndominium in Australia, whether it's in QLD or New South Wales, it has to be approved as a house. The National Construction Code, the national rulebook for buildings, puts every building in a class. A shed, garage or carport is Class 10a, a building nobody lives in, and a house is Class 1a.

You can't legally sleep in a shed approved as Class 10a, however well it's fitted out. That's why a barndominium has to be designed and approved as Class 1a from the start.

Converting a Class 10a shed later is possible in some cases. You then have to meet the house rules in a building that was never designed for them. That usually costs more than designing for them up front.

Once it's approved as a house, your barndominium is assessed like any other home, and five of those rules shape the design the most.

A home needs services a shed doesn't. We design the power, water and wastewater in with the building, rather than adding them once it's up.

If your block has no sewer, the wastewater goes to an on-site system such as a septic tank or a treatment plant. It needs its own approval, a plumbing approval in Queensland or one from Tweed Shire Council in New South Wales. Where the system can go on your block can decide where the house sits.

Is your block in a mapped bushfire prone area? Then the home needs a bushfire attack level (BAL) rating under AS 3959, the Australian Standard for building in bushfire areas. The rating decides which windows, screens and cladding you need.

On the Gold Coast, a building certifier, a licensed professional who checks the design against the building code, approves a shed home. City of Gold Coast also assesses it in some cases, such as a second home or a block under a flood or bushfire overlay, one of the council's hazard maps. Canungra, Tamborine and Beechmont come under Scenic Rim Regional Council instead.

South of the border, the Tweed follows New South Wales planning rules and the Tweed Local Environmental Plan 2014. That plan decides things like whether a rural lot can take a home and how big a secondary dwelling can be. We check it for your lot before the design starts.

A second home on a block that already has a house is assessed differently from a single home on bare land. That's true on both sides of the border. It helps to know which one you're asking for before we start drawing.

Barndominium cost in Australia comes down mostly to the finish inside, more than the steel. The frame goes up faster and spans further than a normal house frame, but everything inside it is the same trade work as a house.

The other big costs are the site work, running services to the building and any on-site wastewater system. These change more from block to block than the building does.

Talk to your lender early. Some lenders treat a shed home differently from a normal house when it comes to finance.