Lord Norman Foster, Hon. FAIA, has worked at almost every scale imaginable, from porcelain demitasses to city master plans. Projects by his London-based firm Foster + Partners populates all corners of the Earth—and someday, perhaps, other planets too. And yet, it was a commission in the tiny Alpine hamlet of St. Moritz, in Switzerland’s Engadin valley, that held the architect’s personal attention for the past few years.
The project entailed the restoration and expansion of the Kulm Eispavillon (literally “ice pavilion,” though it is more like a country club geared toward winter sports). The building is part of the five-star Kulm Hotel, once the heart of this Swiss resort town where Foster resides part time and has built several projects, including the Chesa Futura apartments.
“I have lived in St. Moritz for many years, so it is very close to my heart,” Foster says. “The old Eispavillon had been abandoned for many decades, and there was a great opportunity to revitalize Kulm Park by bringing the building back to life.”
Built in 1905, the original two-story, Art Nouveau club has a storied past. Located on the edge of the 30-acre park just north of the hotel, it hosted the Olympic Winter Games in 1928 and 1948. For years, it served as a wintertime playground for celebrities, including Charlie Chaplin and Audrey Hepburn, but by the 1980s, the club was no longer the heart of the local social scene. By 1988, it was shuttered.
In November 2015, Foster + Partners was hired to revive the structure and add a contemporary outdoor event venue for use in all seasons. “I was approached by the owner, who asked for help,” Foster says. “My suggestion was not just to bring it back to its original condition as an ice skating center, but to create a community focus by adding a small stadium and an enclosure linking an existing skating facility and restaurant.”
Today, the club has been joined by a pair of timber pavilions, located just north of the Eispavillon. At just 580 square feet, the south-facing “sun pavilion” resembles a scale model of the 2,000-square-foot main pavilion. Though conspicuously modern, the pavilions’ prominent use of wood and copper flashing recall the materiality of the original club. “There is a great tradition of wooden buildings in St. Moritz,” Foster says. The pavilions’ primary structure is made from ash harvested in Switzerland, while the curved edge beam and wood slats are made from larch, “a traditional local wood, which mellows beautifully with age,” he adds.
For both pavilions, a round-edged, cantilevered roof is supported by glulam columns, V-shaped in plan, that splay into approximately 25-foot-long, inclined glulam beams, recalling both the surrounding mountains and St. Moritz’s Gothic architecture. Each beam tapers in size, beginning at 43 inches deep and 9.4 inches wide where it meets the column to 6.3 inches deep and 7.1 inches wide. A larch wood-slat soffit attaches to a 4.7-inch-thick CLT roof panel, which is topped with a waterproofing membrane and then a larch wood rainscreen on the skyward side.
Initially, Foster + Partners had designed a more straightforward structure, one with beams perpendicular to the pavilion’s back wall. Shortly before procurement, however, the design team devised the V-shaped pattern, which not only reduced the number of columns (from eight to six in the main pavilion) but also created a visually appealing plane with the cantilever listing up.
The late change in design required Foster + Partners to work closely with timber contractor Blumer-Lehmann, based in Gossau, Switzerland, to design and test new column–beam connections, which consist of concealed glued steel rods, sized to accommodate heavy snow loads. More than 1 foot long and 1.1 inch in diameter, each rod is inserted into drilled openings in the structural members, glued, and then sealed with a timber button.
Among the more exacting components to fabricate was the curved edge beam of the roof eave. The beam comprises double-curved glulam pieces with radii as tight as 23 inches and wood laminate as thin as 0.1 inch. “Such parts cannot be planned with normal timber CAD programs,” says Blumer-Lehmann’s timber construction engineer David Riggenbach, project manager for the Kulm Eispavillon.
Instead, engineers in Blumer-Lehmann’s free forms department use specialized CAD/CAM software to convert Foster + Partners’ 3D models into a format ready for manufacturing. The components were then “precisely machined on all sides on a CNC machine to achieve a perfect fit for the assembly,” Riggenbach says. Foster + Partners says such complexity was well worth the trouble, as it allowed the wood grain and lamination to follow the curve of the beam as well as eliminated the risk of an end-grain cut being exposed to rain and snow.
Fabrication of the pavilions took seven weeks, and their assembly just less than twice as long. According to the architects, the “extraordinary precision” of Blumer-Lehmann’s timber engineering made assembly quite simple. The only challenge was the project’s hard deadline: The new venue was scheduled to host the FIS Alpine World Ski Championships in early February 2017.
In spite of the frigid winter weather, the pavilion construction and club restoration were completed on time, reopening to the public for the first time in nearly 30 years.
Imbued in the architecture is a celebration of past and present, Foster says: “This started with a derelict structure but went beyond to create a new sense of place. I hope that people feel it to be friendly and welcoming, a new extension of the public domain.”