The Kupla observation tower is a basket-style mesh shell made out of 60 x 60 mm bent pine members. Every timber curve in the irregular shape was slightly different, so seven different profiles were prefabricated to assemble the larger components. For each 60 x 60 mm structural member, four 15 mm lamella were glued together in the factory and bent on site to their final shape. The structure was treated with a linseed-based treatment to even out variations in the timber’s moisture. Because of the number of connections, joints were made as simple as possible with each intersection connected by a bolt and reinforced by a two sided nail plate.

Today the tower has become a recognizable landmark for the Helsinki zoo.

Project data

Project completed in July 2002

Architectural Design and Construction: Ville Hara, Tukiko Araki, Elina Hietala, Antti Jyränki, Luca del Gol, Jarkko Rauvanlahti, Jani Ristimäki, Ryoata Sekimoto, Mikko Sinervo, Duarte Soares, Marie Staalsoe, Hanna Tiira, Mika Woll, Regina Yunghans, Chuck Attarzadeh, Joren Bass and Armand Paardekooper Overman

Instructors: Jan Söderlund, Risto Huttunen, Hannu Hirsi and Lauri Salokangas

Photos: Jussi Tiainen

Used materials

  • Structural skeleton – 60 x 15 mm pine battens, bent and laminated into 60 x 60 mm members