 This variation is reflected in the roof line which looks taller at the wings than the spine.The volume of the building is 280,000 m³, constructed from 4,600 tonnes of steel frame with brick infill and floors constructed of hollow blocks to provide over 55740 m² of usable office space".The façade is clad with 33,000 m² Stuttgart-Bad Cannstatt Travertine marble, punctuated in bands of windows decreasing in height with each storey.