The structural concept called for a good fit between all the different components. The customary construction tolerance of 3mm to 5mm for steel structures was far too generous for this project; ±1.5mm was the figure in the specification for the assembly. But even beforehand, the severe deformations caused by the weight of the panes themselves (18t) had to be taken into account. The steel beams were therefore assembled exactly with the help of templates and cambered in their length by applying heat to certain areas. Built according to an exactly calculated erection plan, 40t of steel and glass now form a perfectly horizontal line and even with a roof fall of just one degree the roof drainage functions reliably.