Šentilj is a small town in the northeast of Slovenia, on the border to Austria, with 8,452 inhabitants. The town has grown strongly in the last two decades, and this created the need to build the new sports and leisure centre. It is the biggest investment in the history of the community. The new building complex has a total of 2,290 m² floor area. This is divided between the central sports halls, with 1,400 m2, and a three-storey block right next to them. This section contains the spectator galleries with space for 600 people, and on the other floors, changing rooms, sanitary facilities and utility rooms. A large multipurpose room on the first floor provides views of both the indoor sports halls and the outdoor playing fields. Outside terraces connect the building to the outdoor playing fields and a panoramic view by a balcony on the first floor. A central question that has to be solved in the design of any sports hall is how to build the roof over the hall. The structural solution for the roof is a determining factor for the overall height of the building, and has important implications for costs and compliance with planning regulations. The roof structure and its height also affect the volume of the space that can be used for games and also influence the visual perception of the space. Finally, the ability to use the roof for installation of utilities and sports equipment is also a key requirement of this project category. In Šentilj, the Kielsteg roof spans the building in a single span of 24 m with an element height of just 80 cm. The building is fully self-sufficient for energy, thanks to the solar array on the slightly inclined flat roof.