The HiLo research & innovation unit for the Next Evolution in Sustainable Building Technologies (NEST) platform at Empa in Dübendorf, Switzerland, demonstrates how High (Hi) performance can be achieved with Low (Lo) embodied and operational emissions by combining lightweight concrete structures with novel fabrication and construction methods, and integrated and adaptive building systems. The doubly curved concrete roof of the HiLo unit, spanning an area of 7.85m by 17.20m, was realized with a lightweight and reusable cable-net and fabric formwork system. Such innovation in construction allows the reintroduction of efficient, doubly-curved thin shell structures without the typically associated high labor, time and resource investments. The unit serves as a two-story collaborative and flexible workspace with two closed offices and multiple shared, open office areas.
HiLo’s roof is a “sandwich” shell, with two thin layers of reinforced concrete of only 5 cm (inner layer) and 3 cm (outer layer) thick. Spaced 10 cm apart by insulation blocks, the layers are connected by a grid of thin (3 cm) compressive stiffening ribs and vertical tension rods to activate the entire depth of the section. Combining this lightweight, two-layered structure with the strength derived from the roof’s highly curved geometry, the roof stands freely on five supports, covering an unobstructed space of 120 m2.