Australia’s building standards are not achieving the robustness they set out to, with internal pressure a particular issue during natural hazards, James Cook University Chief Engineer David Henderson says.

Australia’s national building code should introduce a resilience rating system that does “not just push the minimum requirement” but looks at “what we can do more than that,” such as better protecting the building envelope from penetration during cyclones and other hazards, he says.

During a Risk Frontiers webinar, “Analysis to resilience: science to support decision making in a warming world", Mr Henderson noted widespread damage across WA’s Kalbarri township after Tropical Cyclone Seroja in April.

New and old construction were affected alike, he said.

“We’ve got a spread of damage across both the old and new construction. So in terms of modern construction, we’re seeing levels of slight-through-to-total damage across the housing in that Kalbarri area,” he said.

Breaches of the building envelope from wind borne debris pressurised structures, he said, “so your whole roof disappears”.

“A lot of the damage we can attribute to the design criteria we are putting our buildings through,” Mr Henderson said. “In terms of design and construction, it was a lot around internal pressure issues. So it is really not achieving that robustness we are looking for in our building standards.”

A study last year undertaken with the Insurance Council of Australia looking at modern housing – and mapping claims from tropical cyclone events back to wind speeds – found losses were incurred even at wind speeds well below the maximums factored into the building designs.

“A lot of the losses we are seeing are well below what the design level is for our homes, so we’ve got a real issue for what our drivers of loss are,” Mr Henderson said. “We need to really promote aspects of thinking beyond the standard.”

He recommends resilience scores for wind, rain, storm tides and ancillary items such as sheds around the properties, giving practical options to boost scores. His team are currently evaluating four Queensland housing types to look at best-practice retrofitting.

“We need to reduce the drivers of loss to improve our resilience,” Mr Henderson said. “We need to stop doing dumb stuff. We know so much about how to improve our housing and building in terms of design, as well as how we maintain it.”