The curved, Japanese-insired roof of Swiss chocolate manufacturer Max Felchlin's new HQ has been created using RHEINZINK zinc cladding.
Approximately 2400m² RHEINZINK prePATINA blue-grey titanium zinc covering in a double standing seam system was installed. "Titanium zinc is a soft-forming material that can follow the radii of curves well," said Lukas Eschmann from Meili, Peter & Partner. "Its processing, as with the roof truss, follows the idea of promoting regional craftsmanship. At the same time, it stands for the quality and longevity that we and the client strive for. The building and its roof can age gracefully."
The roofing work was carried out by a consortium of three companies from the region and a specialist tinsmith planner.
The tinsmiths installed RHEINZINK-prePATINA blue-grey panels with a system width of 530mm using the double standing seam technique on a self-adhesive formwork membrane, which serves as a construction seal, and the AIR-Z structural mat. The panels are therefore the same width everywhere, but due to the special bonnet geometry and the curves in the roof, they are very different in length on the total of around 20 partial surfaces. "The longest section measures 22.33m, so we had to use long-sliding clamps and placed the fixed points more in the middle," explains tinsmith Benno Lees. At the lower end, the panels, which are laid with rebate sealing tape, taper to a slope of only 5% and drain into a concealed box channel with an impressive 750mm width, so that there is sufficient space for expansion.
It is the same at the top end, where the panels run under striking ridge caps. Galvanised and painted steel sheets serve as the substructure for the ridge elements, which thanks to their special shape, do not have any surface contact with the titanium zinc and ensure optimum ventilation.
Cutting and edging
A logistical challenge was the cutting and edging of the panels. Due to their partly considerable length, the transport route from cutting to size to the installation site had to be as uncomplicated and short as possible. The companies of the joint venture therefore transferred the process to the roof at short notice on a specially erected wooden platform that protected the roof structure and compensated for the roof pitch. A container with the roller profiling machine was placed on it so that the technology could remain on the construction site, protected from the weather and kept locked at night.
The container was connected to a 20m-long roller table on which the panels, cut to length and folded from 600mm belts, ran. From here, the elements could be distributed on the roof with comparatively short distances.
Besides their technical functionality, the ridges on the roof are also important to the architectural concept as they emphasise the lines that run with elegant curvatures towards the tips of the 3 bonnets and, together with the curved main roof surfaces, evoke memories of Japanese temple roofs.
- Roof: 2,400 m² 17 t Double Standing Seam - RHEINZINK-prePATINA blue-grey
- Roof drainage: 1 t - RHEINZINK-prePATINA graphite-grey
- Facade: 4 t - RHEINZINK-prePATINA graphite-grey