Foldable and reusable formwork revolutionises concrete construction

Zürich , January 2025

Architecture doctoral student Lotte Scheder-Bieschin has produced a lightweight, foldable and reusable formwork for concrete vaults at the Swiss Federal Institute of Technology in Zurich (ETH). This allows up to 60 per cent of concrete and up to 90 per cent of steel to be saved.

Unfold Form is the name of the lightweight and reusable formwork for vaulted concrete structures. It was developed by architecture doctoral student Lotte Scheder-Bieschin in Philippe Block’s ETH research group. According to an ETH report, it saves up to 60 per cent concrete and up to 90 per cent steel compared to conventional ceilings.

Unfold Form consists of thin, flexible plywood strips. They are connected to each other by textile hinges and can be unfolded like fans. Four such moulds are quickly and easily joined together in a wooden frame to form a load-bearing formwork with spikes. The concrete is poured on top. “The concrete absorbs these corrugations as ribs,” says the inventor. “These ribs help to transfer loads.”

Once the concrete has hardened, the formwork can be removed from below, folded up again and used again. According to the information provided, the entire system for the prototype weighs just 24 kilograms, but can carry up to 1 tonne of concrete.

“In addition to the material, you only need a template for the mould and a stapler.” The material for the prototype cost 650 francs. As the researcher emphasises, the formwork can be produced and set up without specialist knowledge or high-tech. This means it can be used worldwide, even with limited resources, for example in developing countries. The demand for new buildings is particularly high there.

The second prototype was cast on site by the South African partner company nonCrete, which is committed to sustainable buildings and affordable housing. “The innovative formwork system,” says Scheder-Bieschin, “will one day be used to build high-quality, dignified and sustainable homes in South African townships.”

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