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Researchers from Swiss university ETH Zurich have built a prototype of an ultra-thin, curved concrete roof using innovative digital design and fabrication methods. The self-supporting, doubly curved shell roof has multiple layers, with the heating and cooling coils and insulation installed over the inner concrete layer. A second, exterior layer of the ‘concrete sandwich’ structure encloses the roof, onto which thin-film photovoltaic cells are installed. One day, the residential unit is expected to generate more energy than it consumes.

The prototype was 7.5m high, with a surface area of 160m2. The average thickness of the concrete was just 5cm, varying from 3cm along the edges of the roof to 12cm at the support surfaces. Instead of formwork using non-reusable custom-fabricated timber or milled foam, researchers used a net of steel cables stretched into a reusable scaffolding structure. The cable net weighs just 500kg and the textile 300kg. The construction of the roof also heavily relied on algorithms to ensure that the forces were distributed correctly between the individual steel cable.

This cable net supported a polymer textile that together functioned as the formwork for the concrete. This not only enabled the researchers to save a great deal on material for construction, they were also able to provide a solution to efficiently realise completely new kinds of design. Another advantage of the flexible formwork solution is that during the concreting of the roof, the area underneath remains unobstructed and thus interior building work can take place at the same time. The roof will be built at NEST, the living lab building of Empa and Eawag in Dübendorf, Switzerland.

The once-commonplace building materials have got a technology-inspired facelift in recent years, with concrete reinforced with recycled tyres and transparent solar cubes doubling up as building blocks both hitting the market of late. How could sustainable and innovative building equipment help expand your business?