New wooden apartment blocks with innovative TS3 technology
In Zollikerberg, two apartment buildings in timber construction were recently built, creating a link between Zurich city centre and idyllic nature. Thanks to an innovative connection technology called TS3, the timber construction was also able to bridge larger spans. The decision in favour of timber construction was ultimately made due to its cost-effectiveness and harmony with the surroundings.
It only takes a few minutes’ drive to separate Zurich city centre from Zollikerberg, a part of the village of Zollikon. Having just stood on Sechseläutenplatz in front of the opera house, wide meadows and self-picking fields open up shortly afterwards. Just a stone’s throw away from Forchstrasse, which directly links the town and the countryside, two wooden apartment blocks were completed last year – on the site of a farm that is still inhabited and farmed.
Harmony between tradition and modernity
Sheep used to graze regularly on the estate’s large meadow. Today, two four-storey buildings with a total of 22 rental flats tower above the grass. The two apartment blocks form a harmonious ensemble, which could possibly be supplemented by a third building at a later date, should densification be required. At the start of planning, it was not yet clear whether the buildings would be timber or solid construction. The clients had not made any specific specifications when they announced a private competition in 2018. However, chance favoured timber construction: the Zurich-based firm Merkli Degen Architekten, which was invited to take part in the competition and won, was working with Timbatec AG at the time. Together with the University of Applied Sciences Biel and ETH Zurich, the well-known Swiss engineering firm was developing a new connection technology to bridge larger spans with cross-laminated timber panels – without beams or additional intermediate supports.
The future of construction
In future, it should therefore be possible to achieve with wood what was previously only possible with reinforced concrete. TS3 connection technology was still in its infancy in 2018, but is now well established. Solid timber panels that can form entire floor slabs open up completely new possibilities for timber construction.
“It was purely by chance that we became aware of TS3,” explains Ueli Degen, one of the founders of Merkli Degen Architekten. “We were originally talking to the engineers at Timbatec about another timber construction project.”
They told us about the development of their latest connection system and presented us with an example. This ground-breaking technology has stayed with us ever since. At some point, we came up with the idea of using TS3 for the construction project in Zollikerberg. Before deciding whether to use timber or solid construction, thorough investigations and comparisons were carried out. In the end, the timber design prevailed, which was later realised by the company Holzbau Oberholzer GmbH. By using a timber building, it was possible to create a harmonious connection to the existing farmhouse, which is also made of wood.
The combination of a timber construction with TS3 technology also promised to be an economically attractive solution that would also significantly shorten the construction time. Nevertheless, it took a while before the clients decided in favour of timber construction. Five years ago, when the buildings were planned, a lot of persuasion was still needed to push through a timber construction of this size.