The former casting house of the blast furnace 1 at the “Landscape Park Duisburg” was to be upgraded to be the venue of the festival “Ruhr Triennale”. Pneumatically supported foil cushions make up the retractable roof, which rides on wave-like tracks. This wave elegantly undulates from the casting house across the existing pipes. The distance of approximate 20 m between the two wave-like tracks is bridged by trussed girders. In groups of two the girders are coupled and equipped with four rolls. In between these “carts” there are frames hanging from hinged connections. Together the carts and frames cover an area of approximate 29 x 20 m. Each of the five carts or rather four frames is filled with an own ETFE-foil cushion.