Holzapfel & Schulze began work on the newly constructed reinforced concrete roof support structure, which was topped with a vapor barrier and 180 mm of roof insulation. The insulation layer is covered with a roof underlayment. Next comes the counter-battens layer, which creates the ventilation space, followed by the load-bearing sheathing. To protect the structure from the elements during the construction phase, a continuous separation layer was installed as the first step. As construction progressed, the RHEINZINK-AIR-Z textured mat was installed, ensuring the functionality of a textured separation layer. This combination of separation layers ensures the safe drainage of any condensation and also improves the sliding ability of the panels during thermal expansion and contraction.

One challenge on the highly segmented roof was the roof layout, which had to be redesigned for each section between the gables, skylights, and loggias. As a result, there was no standard width for the roof panels; instead, they were predominantly cut to size and seamed on-site from 670-mm-wide strips, each with its own individual dimensions. Despite this variety, the roofing appears cohesive because careful detailed planning ensured that the seams run in a straight line across every section, from the main roof to the mansard. A harmonious line pattern was also intended on the courtyard sides, where approximately 180 skylights had to be integrated into the main roof surfaces of the various building wings. For this reason, the skylights were not framed with standard flashing frames but were instead fitted using traditional folding techniques. Depending on their position, the skylights are equipped with electric drives and sunshades.

The downspouts of the roof drainage system run along the front of the facade, just like the historic original. Because they are consistently designed as cornice gutters, the rain gutters blend discreetly into the architecture and are not recognizable as separate structural elements. The same applies to roof ventilation: Perforated metal sheets for ventilation are located at the base of the mansard roof, at the junction with the main roof surfaces, and at their upper ends; these are not visible from the normal viewing position below. The choice of material was particularly crucial given the finely structured roof design.

RHEINZINK-prePATINA ECO ZINC blue-grey provided a material that impressed with its high-quality appearance and installation properties. The surface ensures a uniform overall appearance. In the case of complex connections and custom-cut panels, the pre-weathered material also demonstrated its reliable workability: it is stable to handle, easy to fold, and particularly well-suited for clean, precise detailing. This made it possible to implement the roof’s challenging geometry with technical precision and visual harmony throughout—fully in line with historic preservation requirements and the overall architectural impression.