About 1200 Auckland houses destroyed by cyclones could become a resource for a more sustainable future.

University of Auckland Associate Professor of Architecture Mike Davis has launched a research project identifying reusable materials in houses that have been deemed unsafe, after being hit by Cyclone Gabrielle and floods in 2023.

The aim is to turn cyclone-damaged houses into an “urban mine” that reuses as much as possible, saving the planet from the pressures of endlessly providing brand new materials, says Davis.

“The tragedy of these houses being lost would be deepened if all the reusable materials in them were dumped in landfills.

“We need to look after the land, which is not about putting stuff in landfills, it’s about reusing materials and putting them into a circular economy,” says Davis, who works in the University’s Māori and Pacific Housing Research Centre, MĀPIHI, and Future Cities Research Centre.

Davis is mapping what materials have come out of the red-stickered houses and where these materials have gone.

“Then we can start to predict what might come out of houses that have been red-stickered or that are damaged in storms in the future,” he says.

Hand-held devices and drones are making 3D scans of various types of houses, such as Keith Hay and Universal homes, villas and bungalows, and state houses. This helps identify the quantities of various building materials typically found in each type of house.

“Building a knowledge bank of the reusable materials available from red-stickered houses will help the construction industry know what materials are likely to be available for reuse,” Davis says.

The project also aims to highlight environmentally harmful materials coming out of cyclone-devastated houses. This information will be used to develop more sustainable building practices for the future, he says.

“One example is polystyrene, which doesn’t go away, so when a house comes down after 50 years, it’s a massive problem.

“We want to look for alternatives and ask what we can learn about building better in the future.”

Davis says older houses tend to be richer repositories of valuable materials, such as kauri, matai and rimu timber.

“More than 50 percent of timbers can often be reused from earlier buildings.

“Once you get into houses from the 2000s, lots of materials are glued together and it’s much harder to reuse something that’s been glued.”