Sibelius Hall Lahti

The design competition for the construction of a congress and concert centre from timber was announced in Lahti in the summer of 1997. The point of departure for the project was to discover innovative timber engineering solutions and to set the new structure in a meaningful relationship with the old joinery factory located on the same site.

A price ceiling was determined for the project. To ensure that it would not be exceeded, the second phase was organised as a “design and construct” competition to which three shortlisted designers were invited to submit entries. The Employer had already defined the acoustic requirements in phase 1 and invited Mr Russel Johnson from Artec Consultants Inc. to serve as an acoustics expert for all the design teams. The hall layout was to satisfy precisely defined criteria.

To adapt the large building volume to the existing old industrial building, the complex was subdivided into blocks whose structures followed the simple and purpose-built lines of factory buildings.

Access to the building is through the oldest part of the complex. The entrance hall, the most important auxiliary facilities for congress activities, the information desks, sanitation facilities and cloakrooms were placed on the ground floor in the joinery factory. From the entrance hall there is direct access to the lobby known as the “Forest Hall”, restaurant and exhibition wing. Smaller rehearsal and meeting rooms are found on the first floor. The rehearsal rooms, clad with light-coloured birch, offer a view of Lake Vesijärvi.

A covered translucent urban space was built to link the congress and concert centre to the old joinery factory; this space, called the Forest Hall, with its view of the lake, seeks to convey the feeling of space associated with a pine forest. The clearly defined lobby is the unifying core of the building. At the same time, it serves as a banquet hall in connection with concerts and congresses and offers a venue for small trade fairs and exhibitions. Next to the entrance, there is a congress office clad with birch bark.

The concert hall offers seating for 1100 people and the “choir balcony” for 150. The hall is designed for concerts, congresses and recording sessions.

The actual concert hall is lined with “echo chambers” that make it possible to adjust the reverberation time up to cathedral levels. On the stalls floor, the echo chambers serve as entrances. Access to the concert hall is via acoustic gates and a “timber cathedral” delineated by inclined massive prefabricated wall units made of sand-filled Kerto-LVL building units.

The acoustic characteristics are regulated by means of the wooden canopy suspended above the orchestra. The dynamics of the wooden hall are accentuated by grooves in the acoustic doors that generate a diffuse field for the deflected sound.

The seminar and rehearsal rooms and the performers’ foyer are housed in the congress wing that is placed parallel to the lakefront boulevard. The foyer features an outdoor patio that offers a venue for a wide variety of events. The best view from this floor is towards Lake Vesijärvi.

The load-bearing structure in the Forest Hall consists of a large-scale frame resting on nine wooden columns. Reminiscent of the branches of a tree, this 3D structure made of glue-laminated timber supports the wooden roof sections. The massive glue-laminated pylon from turned spruce supports a frame measuring 11.2 x11.2 m. The members in the space structure are interlinked by dowel joints. The actual load-bearing structure in the hall consists of massive glue-laminated frames that support the roof and glue-laminated trusses on which the ceiling structures rest. The frames also support the inclined exterior wall of the building, which, due to the acoustic properties of wood, was made of multi-layered timber. The innermost layer in the exterior wall of the concert hall consists of glue-laminated units filled with dried graded sand. The inclined external walls are clad with weather-resistant varnished plywood boards. The plywood cladding and the insulation layer behind it were designed to improve soundproofing.

Finnish Wood Award 2002