The blue HOTT building near the Helsinki Airport was designed and constructed for the companies of the Finnair Group. The floor plan is flexible: the spaces can be adapted to meet the varying needs of different tenants and organisational changes during the projected hundred-year life cycle of the building. The area of one storey can be divided into as many as six separate office premises. Nearly 900 employees work in the building.
The exterior appearance of the building is defined by acid-proof sheet steel panels, aviation-related wing-like sunshades of office windows and pergola canopies on a roof terrace. Based on nanotechnology, the facade cladding is the first of its kind in Finland both as an architectural element and as a technical solution. By means of nanotechnology, the thickness of the oxide layer on sheet steel panels has been adjusted to reflect only the blue wavelengths of sunlight. The hue on the surface of the steel panels changes along with changing daylight as the result of an electrochemical reaction, and the colour of the surface can be influenced by changing the duration of panel treatment. This treatment combination made it possible to achieve a facade that is powerfully vivid owing to the impact of the environment and the direction of sunlight.
The feel of the interiors is light thanks to large glazings and pale colours. The high lobbies have pale sandstone flooring, and the ceilings and walls are clad with white-stained birch battening. Deep blue stucco on a restaurant wall serves as a contrast. The building has seven storeys. Besides lobbies and restaurant, the ground floor houses an auditorium, meeting rooms and gym. Above them are five office floors. The top floor contains a bathing facility with log sauna that opens to a roof terrace. On the terrace, outdoors, you can plunge into a wooden bath barrel. The terrace is also connected to meeting rooms.
As for structures, the HOTT office centre is a hybrid. Besides steel and concrete, wood and aluminium are materials used in the frames of the different parts of the building. The basement floors were cast on site, and the frame of the office storeys was made of concrete-filled steel columns and steel beams. The planes consist of hollow-core slabs, and the stairwells have structures made of prefabricated concrete units. The frames of the high entrance lobbies are steel and those of the facade units are laminated wood. The building is heated and cooled with geothermal heat: 34 drilled holes, eight kilometres in total length, provide the required heat in winter and cooling in summer. All equipment was chosen with consideration of electricity and water consumption: ventilation is optimised by adjusting it to meet the needs of different spaces, lighting is regulated automatically according to daylight level and the movement of people, and all water installations are water saving.