The concrete structure of the existing building was maintained and adapted to meet current requirements. The U-shape of the extension envelops the existing building on the northwest, east and southeast. Along three sides, the facade of the library is clad in copper panels. On the southeast the ground floor features a recessed glazed facade that borders a 50 m long outdoor terrace. The large café with reading lounge is situated on its interior side. Slender columns along the northeast alleviate the closed impression of the facade structure. With cross sections of 38 × 20 cm, 5–12 m tall and placed according to a dense 40 cm grid, they follow the eave ascending from south to north. While they are also clad in copper on the exterior, they have a light-coloured exposed concrete surface matching the 1.20 m tall roof beams they support on the interior. The spaces between the columns allow daylight to enter the large reading room, providing it with an atmosphere reminiscent of a forest clearing. A tall portal in the south leads visitors into the entrance area. JKMM also designed the interiors, following the philosophy of Alvar Aalto, who was inspired by forms and colours from nature: Surfaces of walls and ceilings are white or clad in light-coloured oak panelling, sublimely contrasted by light fixtures and handrails consisting of brass and upholstery made of wool and felt in subdued colours.
Fyyri – in the Finnish language, the new name of the library means “steam ship boiler” – is much more than a publicly accessible archive. 4700 m² of floor area with spaces for toddler groups, youth clubs, a café, exhibitions and events transform this institution into a vivid place of encounter for the community.
