The Niedersachsenstadion (now HDI-Arena, formerly AWD-Arena), built on a mound of World War 2 rubble, hosted the World Cup in 1974 and the European Championship in 1988. After the construction of a new stadium on the former footprint, the new stadium hosted the World Cup in 2006.
In 2000 the Schulitz office, in collaboration with RFR/Paris, won the international competition that focused on providing a roof over the entire spectator stands. The office also won the following investor's competition for the stadium´s transformation from a multi-use facility into a dedicated football stadium. The first competition's roof design was retained.
The new roof concept reflects the original characteristics of the stadium, separating the lower stands from the covered upper stands on the west side. In order not to increase the loads and reuse the existing foundation while at the same time doubling the roof surface, the old tied-back construction was abandoned. In the new design the forces were short-circuited using a compression ring. The division of the roof into an opaque outer part and a transparent inner one lead to two interlocked concentric spoked-wheel-systems, the inner one consisting of a light-weight tensegrity structure, covered with ETFE foil. This single-layered ETFE roof, the largest of ist kind, with its UV-permeability reduces the need to regularly exchange the grass on the pitch, a common problem in many modern football stadia.
The stadium still retains the harmonious integration in the park-like landscape around the Maschsee Lake as well as its identity expressing the achievements of the reconstruction period in the 1950s.
The light weight roof structure in conjunction with its UV-permeability that diminishes the need for grass exchange in the pitch is a great example for sustainable stadium design.