How our bushfire proof house design could help people flee rather than risk fighting the flames

By 2030, climate change will render one in 25 Australian homes ‘uninsurable’ if greenhouse gas emissions continue unabated, with riverine flooding posing the greatest insurance risk, according to new analysis by Climate. Council.

As an architecture professor, I find this analysis dark, but not surprising. One reason is that Australian housing is largely unsuited to the challenges of climate change.

In the past two years alone, we have seen over 3,000 homes razed in the 2019-2020 mega-fires and over 3,600 homes destroyed in the North Rivers region of New South Wales in the recent floods.

Building homes that are more resilient to the impacts of climate change is one way to protect ourselves against future catastrophic conditions. I’m part of a research team that developed a new bushfire-resistant house design, which won an international award last month.

We hope its ability to withstand fires will encourage homeowners – who would otherwise stick around to defend their homes – to flee when bushfires encroach. Let’s take a closer look at the risk of bushfires and why our housing design should one day become a new Australian standard.

The house would be made from a locally sourced recycled steel frame.
Deborah Ascher Barnstone, Author provided

Today’s houses are easy to burn

Climate Council analysis finds that among the 10 Australian voters most at risk from climate change impacts, one in seven homes will be uninsurable by 2030 under a high emissions scenario. This includes 25,801 properties (27%) in the Victoria electorate of Nicholls and 22,274 properties (20%) in Richmond, NSW.

Read more: Properties under fire: Why so many Australians are insufficiently insured against disasters

Bushfires are among the worsening hazards rendering homes uninsurable and pose a particularly high risk to many thousands of homes in eastern Australia.

For example, the Climate Council found that 55% of properties in the electorate of Macquarie, NSW, will be at risk of bushfires in 2030, if emissions do not come down. This increases to 64% of properties by 2100.

The typical Australian house was not designed with bushfires in mind, as most were built decades ago, before bushfire planning and building regulations came into force.

The remains of a house destroyed by a bushfire in Perth, 2021.
Image AAP/Richard Wainwright

This means they incorporate combustible materials, such as wood and plasterboard, and have features such as gutters that can trap embers.

Additionally, gaps between building materials are often too large to keep embers out, which means spot fires can start inside the home. And many houses are located too close to fire-prone grasses and trees.

Indeed, at least 90% of homes currently in bushfire areas are at risk of being destroyed in a bushfire.

How our new design can withstand fire

The bushfire-resistant prototype house we designed won the top award from the New Housing Division of the United States Renewable Energy Laboratory’s Solar Decathlon.

The house has three pavilions that can be built at different times to reduce costs.
Deborah Ascher Barnstone, Author provided

The house would be made from a locally sourced recycled steel frame. It would be mounted on reinforced concrete pilings to minimize its disturbance on the pitch, touching the ground only lightly. We thus contribute to preserving the biodiversity of the site.

The main building material is rammed earth – natural raw materials such as earth, chalk, lime or gravel – which is not combustible.

The roof and some coverings are made of fire-resistant corrugated iron. Its glazed facades are equipped with fire shutters made of fiber cement sheets, an incombustible material that can be closed to seal the house.

Read more: How a bushfire can destroy a home

It is important to note that the gaps between these construction materials are 2 millimeters or less.

Pitched roofs slope inward to capture rainwater. And since the roofs are made of corrugated iron, which has channels, the house does not need gutters.

These channels guide rainwater into two open retention basins on either side of the entrance and into protected reservoirs under the house. It also helps to protect the house in the event of a bushfire, as it means the fire cannot enter from below.

A view of the entrance bridge and retention ponds.
Deborah Ascher Barnstone, Author provided

When bushfires hit, the risk to life is highest when people stay and defend their homes. A design that can withstand fire on its own entices its owners to leave.

But it should be noted that it is do not a bunker where people can take shelter. No matter how well designed a home is, it will always be too dangerous to stay in when a fire breaks out, and especially in the catastrophic and extreme fire conditions that we are increasingly experiencing.

It is also profitable

The estimated cost of construction is between 400,000 and 450,000 Australian dollars. We have deployed several strategies to reduce costs:

  • the house is designed to be energy and water independent, so it will not need city utilities

  • it uses common construction techniques and is based on the construction industry standard for sheet metal, so it does not require specialist builders and wastes no materials

  • Rammed earth is relatively inexpensive as it can be obtained from many places, often for free. We also consider using recycled materials whenever possible.

Aesthetically speaking, the design also presents an elegant home space that is flexible enough to easily adapt to almost any setting.

The house is characterized by open spaces and indoor/outdoor living.
Deborah Ascher Barnstone, Author provided

Read more: 12 easy ways to reduce the risk of bushfires in older homes

The next step is to build and test a prototype of the house so that we can evaluate its performance and make improvements. We are currently talking with potential funders to make this happen.

As climate change drives more disasters, Australia must prepare for the destruction of thousands more homes. Innovative architecture like ours gives homes and valuable possessions a chance to survive future disasters.