Architects are often faced with challenging construction projects that require creativity and technical sophistication. The new indoor tennis centre at TC Lengg in Zurich is an impressive example of this. This construction project not only required innovative solutions due to the special shape of the roof, but also a sophisticated concept for realisation in a confined space.
A construction project with limited space
The new indoor tennis centre was built in a densely built-up area between a lake waterworks, existing tennis courts and the Lengg family gardens (allotments). The construction site was severely restricted: The working space around the building was only 2-3 metres in places. In addition, the access road ended in a narrow cul-de-sac, which made the delivery of building materials and the use of large machinery considerably more difficult.
The right roof structure for the timber construction
The primary structure of the hall consists almost entirely of timber trusses and purlins. Visible timber cladding in a light white colour was mounted on top of this. This was followed by the vapour barrier, thermal insulation with highly efficient GRP holders and a final standing seam cladding. The rounded connection areas, such as the verge and wall connections, which were realised with rounded flashings, were particularly challenging.
A central feature of the roof covering was the curved BEMO standing seam sheets, which were designed without cross joints to ensure a durable and functional roof covering. And it was precisely these curved sheets that presented a particular challenge.
Curving directly in the hall
The standing seam sheets were around 23 metres long and had a so-called pitch of around 3.7 metres. Due to these dimensions, it was not possible to deliver the sheets ready-curved. Added to this were the limited space available and the narrow access road. Under normal circumstances, a large open area around the building is required to produce or curve standing seam sheets on site.
In concrete terms, for this project, with a sheet length of 23 metres + curving machine + curving sheets, as well as an approx. 8-9 metre wide storage area and movement area, this would be 400 m². However, this area was not available here.
The solution was as clever as it was effective: the curving of the standing seam profiles was carried out directly in the tennis hall. A detailed plan with precisely calculated entry and exit radii and a defined sequence ensured a smooth process. The surrounding trench was built over and the curved sheets had to be lifted onto the roof by hand due to the space available, as it was not possible to use a crane.
Successful realisation despite complex conditions
Thanks to the meticulous planning and excellent collaboration between the roof + façade installation company, the timber construction contractor and BEMO, the project was successfully completed. The construction work was completed on schedule and TC Lengg is now delighted with the extended playing facilities, especially in the winter months.
The high degree of prefabrication of the wooden elements and the creative solution for curving the standing seam panels directly on site contributed significantly to the efficient and targeted realisation of the project. This construction project impressively demonstrates how innovative planning and well thought-out realisation can lead to successful results even under difficult conditions.
