Fighting fire with good design
Last summer’s catastrophic bushfires have turned the spotlight on how smart home design can save property and lives.
Kate and Anthony Nelson don’t believe in luck. On the night of 30 December 2019, as the Sarsfield couple watched flames roar up the valley from the Nicholson River, their first thought was: “Right, game on.” When they built in the bush 15 years earlier they knew that fire would come to them some day, and careful planning and housekeeping ensured they stood a chance when it did.
Slides: Kate and Anthony Nelson in front of their Sarsfield home.
The Nelsons’ modest house – plus a carport/gym and workshop – are simple but stylish structures clad in non-combustible Zincalume steel. “We paid particular attention to flashing,” Anthony says. “We’ve got it physically flashed on the outside to be ember-proof, and we doubled that up on the inside using non-flammable insulation materials that won’t ignite when they’re exposed to heat.”
Concrete, steel balustrades, an absence of eaves, minimal glass, and steel shutters that act as awnings over windows and can quickly be fitted to doors, all played their part, along with a lack of shrubs or garden around the house. The weakness was the elevated timber walkways linking the structures. Countering this was their chief weapon – a supercharged sprinkler system that accounted for roughly a fifth of the overall $350,000 build.
“Our system is designed to turn on when you’ve basically got flames licking at your building, and it’s monsoonal – it delivers the equivalent rainfall of about 10 millimetres per minute,” Kate says. The effect is “like a shower around the outside of the house”. A rotational impact system shooting water onto the house acts as a second layer of defence.
The night of the fire is captured on Kate’s website through several videos shot from fixed GoPro cameras. The fire front passed in half an hour, and after two hours of “blacking out” with hoses the Nelsons thought about having a beer, but collapsed into bed instead at 4am. A week later they sat down in their unscathed home to watch their latest home videos and thought, “Wow!”
Our system is designed to turn on when you’ve basically got flames licking at your building, and it’s monsoonal – it delivers the equivalent rainfall of about 10 millimetres per minute.
Kate and Anthony are at pains to point out that staying to defend a property from bushfire is only for the most thoroughly prepared. And in their case, the home itself comprehensively ticked all the boxes for bushfire resistance.
Their non-combustible cladding, for starters, is a critical safety measure according to Dr Ian Weir, research architect and founding member of the Bushfire Building Council of Australia. “Non-combustible materials – let’s actually make it so they don’t burn.”
Ian regularly advises “Mums and Dads” who have bought land only to discover it’s Flame Zone-rated – the highest Bushfire Attack Level (BAL) measurement of a building’s potential exposure to ember attack, radiant heat and direct flame contact. He tells such buyers they’re privileged to build there, “but what goes with that privilege is the responsibility of building so you’re not part of the problem”.
In fact, nine out of 10 Australian homes in bushfire-prone regions are part of the problem, because they are not ‘bushfire resilient’, most pre-dating the introduction of bushfire building standards in 1991.
Of 2133 homes destroyed during the devastating 2009 Black Saturday fires, just 5.4 per cent were built to bushfire construction standards. Seven years later, only 18 per cent of buildings in the Wye River fire footprint met those standards. And even houses considered bushfire resilient on paper can be fatefully weakened by poor maintenance, non-compliance, and having combustible fuels within 10 metres.
Slides: Earth-sheltered housing design concepts by Baldwin O'Bryan Architects.