Wood plays lead role in 14-storey wooden, Swiss building

There is a first time for everything. In this case, we are talking about a wooden tower being built in Prilly, Switzerland, a municipality of over 10,000 inhabitants in the Swiss canton of Vaud near Lausanne, which will soon be completed. It involves an innovative and future-oriented construction method with a specific energy concept. That makes it an architectural example worth taking a closer look at.

The 14-storey wooden building currently being completed on the west wing of the Malley Lumières shopping centre in Prilly is a real eye-catcher. And that's not all: it is the first high-rise building with a wooden structure in French-speaking Switzerland. Although the base consists of concrete walls and steel components, 80% of the supporting structure is made of wood. In addition, there is something else that may be misleading at first glance: the imposing extension does not rest on the foundations of the existing building. On the contrary, the technical mastery is made possible by the lightness of the timber construction and the construction of a bridge structure. Malley Phare's architects and engineers have understood how to combine materials to get the best out of them. And that's not all: the building itself must also put its best foot forward.

“Before starting the architectural design, we conducted a survey so that we could accurately assess the target group for this new neighbourhood in Malley”, explains Florence Chacornac-Mages, Communications Director at CCHE. “The modern, innovative, urban and smart architecture is mainly aimed at young urban dwellers who are interested in smaller living units, but with extensive, connected living spaces. These people don't want redundant spaces, they want extra rooms. We call these ‘joker rooms’ whose purpose is to host friends or family or to telecommute occasionally. Young city dwellers rely on a soft mobility strategy, which the neighbourhood can offer them thanks to trains, buses and soon trams.”

The building meets these requirements in the form of 96 rental flats, including nine studios, 12 lofts, 29 two-bedroom flats, 33 three-bedroom flats and three four-bedroom flats. There are also eight joker rooms and six co-working spaces and 11 communal washrooms. On the roof of the 60-metre-high building, we notice a bar with breathtaking views over Lake Geneva.

The wooden high-rise not only looks modern and elegant, the facade is at the same time focused on the future. Not only on the roof but also on the facades we see photovoltaic modules that turn the entire building envelope into its own power plant. The aim is to produce 250,000 kW per year in this way. An ingenious facade pattern of slits, incisions and loggias was developed to make this building envelope as lively as possible. In addition, the photovoltaic panels lining the facades contribute to Malley Phare's distinctive appearance. They are expertly distributed: more and denser solar panels on the south facade, fewer and more dispersed on the other, less sunny facades to provide more transparency here too. Last but not least, a central corridor running from north to south accentuates the front. That corridor connects the flats and creates rooms three times as high at both ends.

A major advantage of timber construction is the possibility of highly prefabricated components. In this case, the elements, which form a 7.7-metre grid, are delivered to the construction site by truck and can be assembled immediately. A total of 3,000 square metres of pinewood panels are stabilised by 800 tonnes of steel structures. Three trusses on three triangular levels, representing nine floors, were mounted one after the other on the tower's load-bearing west wall and moved using four hydraulic cylinders. The weight of the structure to be moved varies between 100 and 350 tonnes with a span of 46 metres. Each relocation has to be carried out carefully and takes half a day, sometimes even a whole day. To bring more variety to the facade and break the rhythm of the structure, the tower eventually consists of three blocks of five, four and five storeys with three different types of flats, with each floor having between seven and 10 flats.

As protection against excessive sunlight, but also for acoustic reasons, loggias were added that surround all flats, except the studios. These fully-fledged living spaces with an area of 10 to 15 square metres enrich the flats and also act as heat regulators. To counter the incident light in the evening and morning hours, the window fronts are fitted with Louvre blinds. Preparatory work began in spring 2022, with completion scheduled for late 2025.

© all pictures: CCHE