(July 2011) The Frutigen palm house (Tropenhaus Frutigen) is one of Switzerland’s most unusual buildings. Unusual first for one, its combination of function and location: situated on the highlands of Bern it serves as a location for cultivating tropical fruit and caviar. Repeat: in the high Alps of Switzerland, well-known as a ski-resort or for alpinist sports, citizens of the area are cultivating pineapples, bananas and caviar – ecologically, as well.
And, the façade is also unusual. Made of concrete and resembling the surrounding escarpment complete with cracks and crags, it is interspersed with natural stone slabs conceived by Gauer Itten Messerli, architects.
The prequel has its roots in the high mountain grounds. The Doldenhorn group enjoys a constant flow glacial melt water. The mere mass of the rock exerts such pressure that water remains at a constant 20°C.
The mountain houses a railway tunnel, causing an ecological challenge: the water trickling into pipes along the tunnel’s path collects to a 100 l/sec stream. To route this amount of water into a natural waterway would have disturbed the sensitive eco-system.
Thus the idea was born to cool the stream of water by leading it through the Frutigen tropical enclave. It provides the necessary heating for the complex and other buildings in the area. Additional energy is provided through solar collectors or recycled waste according to a press release.
Of course the palm house is not meant to provide large amounts of farm produce. Primarily it is a tourist attraction for locals and tourists alike: a culinary oasis with tropical ambiance, complete with orchids, spices and an exhibit on alpine and tropical regions and finally the possibility to visit the palm-houses and fish ponds.
The visitors’ complex stretches much adapting to the natural environment like an elongated native rock. The effect is achieved with the help of 69 irregular elements made of coloured concrete by Creabeton company.
But that’s not the only association to mountains. During construction of the railway tunnel, a number of different types of rock were encountered. The diversity of stone is mirrored in the complexe’s exoskeleton.
Thus multifaceted slabs of black Nero Assoluto granite were let into the façade. They represent coal and carbonite rock through which the excavating equipment had to make its way. Onsernone gneiss slabs are reminiscent of the mountain’s limestone strata. The 3cm-thick natural stone slabs were produced by Frutigen Slate manufacture.
Mounting the stone slabs on the concrete wall was a special challenge.
The concrete slabs measure 7 m x 3,5 m and weigh 8,5 t. The smallest is approximately the size of a sheet of 9 1/2″ x 11″ paper. Mounting the façade elements took 3 days of steady heaving with the assistance of a 160 t crane. The building costs amounted to 30 million SF.
Gray Itten Messerli Architekten (German)
Photos: Tropenhaus Frutigen