The nature of urban space and natural elements as starting points for the design
The key criterion used in the selection of architectural planners was the evidence shown about their expertise in the construction of large wooden buildings. The designer chosen was APRT (Architectural Studio Artto Palo Rossi Tikka Architects). Architect Teemu Palo was the chief designer, and Architect Juhani Suikki worked as the project's architect. APRT is an international architecture, urban planning and design studio, which has designed, for example, Sibelius Hall, the receiver of the Wood Structure of the year 2002 in Lahti.
City as a space forms the core foundation for APRT's design work, and the nature of urban space is a prominent feature of many individual buildings, including Pilke, designed by the company. Natural light as well as river and hill landscapes play key roles in Pilke architecture. Study of the relationship between built environment and nature is, in fact, a recurring theme in APRT's works.
Pilke functions mainly as an office building, providing work for 135 people. There are also 650m2 of exhibition space for the Pilke Science Centre. When the planning of the building started, the challenge was the size of the area of the building lot and its ten-metre height variation. Although Lapland is big and sparsely populated, the size of Pilke's building site is tightly limited. The design was affected by the adjacent Arktikum building, the distance to which, at its shortest, is 8 metres. The fire safety of the wooden building must also be paid attention to already at the design stage.
A workable solution, as far as the cityscape was concerned, was to use the new building to emphasize the Arktikum Square. The side of the Pilke House that faces the square is the main façade and appears first as we approach the buildings from the city centre. With the advance of the Pilke construction, the square has become a sheltered space, an opening warmed by the shining sun.
Quick building construction
Pilke's construction schedule was tight. Its construction started on 15th September 2009, and the building was handed over to the user on 11th October 2010.Due to the tight schedule, the work at the site was carried out in many shifts. The strength of the labour force at the worksite was, on average, 80 people. As the building workers came from within 100 kilometre radius of the construction site and a large number of the subcontractors were local, the site was of great importance locally. The degree of domestic content of Pilke is over 90 per cent.
Large, wooden office buildings like Pilke are still rare in Finland. Wood-based construction methods and techniques are familiar to Finns, however, as a result of smaller wood-based construction targets realized. The main challenges of a big wood-based construction site are scheduling, planning of work stages and foresight. The site requires and also allows the use of traditional carpentry skills. Due to the height of the building and the existence of an open lobby area, a lot of lifting work was done on the site. A tower crane, with which the elements and timber were lifted on various floors, stood in the exhibition area up until the final stages.
Pilke's structural solutions
The construction engineering technique used in Pilke is wooden column-beam structure. Its load-bearing structure consists of laminated wooden columns and at its best, beams of the height of 1.5 metres. Primary and secondary structures can also be observed in the indoors of Pilke. Pilke basement, the foundation, is of concrete. Due to the height differences on the site, the sides of the lower levels facing the ground alongside Ounasjoentie were strengthened by special earth wall structures. The building's column-beam structure is stiffened by concrete public stairwells and elevator shafts.
Although assembled of wooden outdoor wall panels, the facade of Pilke remains uniform. Also, the external wall panels are load-bearing. The structure of the intermediate floor is made up of softwood plywood and surface concrete slab placed on load-bearing wooden beams.
The structure and substructure of Pilke's roof are based on roof trusses erected on load-bearing beams. The roof trusses take care of the falls of the roof, and drainage is based on the "goose back" principle. Pilke is not flat-roofed, and the roof covering material is bitumen membrane.
The office rooms are partitioned with light, framed walls. Thus it is reasonably easy to change the size of workspaces as well as to create team-work spaces and larger complexes. This also allows flexible manipulation of facilities as needed.
Pilke is connected to the district heating network of Rovaniemen Energia Oy. Its air-conditioning system is based on heat recovery, and the two-level engine room for air-conditioning is located on the top floor of Pilke.
The fire engineering design divides Pilke into two parts that are separated by a compartmentalizing wall of the height of the whole building. Pilke has sprinkler and smoke extraction systems with their sensors for fire situations. In case of fire, the open corridors on the top floor are closed with smoke curtains, which makes safe evacuation from the building possible.