Asunto Oy Loviisan Lippulaiva

The Lippulaiva (flagship) project showcases the future of wood construction. Rising in the midst of Loviisa’s housing fairgrounds, this wood-framed apartment building takes the environment into account.

Read the article in Finnish here.

Ensuring a magnificent sea view for all the apartments and their balconies was the core of the design mission. The demanding maritime environment and the site’s location influenced the architecture, which had to match with both the old wooden buildings in the nearby centre of Loviisa and a residential area from the second half of the 20th century. Occupying a prominent place on Loviisanlahti Bay across from the centre of Loviisa, this multi-storey building rests in harmony with the lower-built skyline along the bay and the Loviisanjoki River estuary.

The building’s colour palette allows it to blend into the larger landscape across the seasons.

Inside the apartments, the design aimed to maximise visible wood by using CLT surfaces on most interior ceilings and by recycling left-over CLT pieces from the façade to back fixtures. The façades are made entirely from wood except for the balcony glazing and other supplementary building components.

An ambitious goal of the architectural design was to leverage CLT modular construction methods for this wooden apartment building, in essence, constructing the apartments at the factory using prefabricated modular units. The planning and construction schedule was extremely tight, and the modular building method meant that plans could no longer be updated or changed on-site – deviating from the normal practice of apartment building construction. The zoning plan set rather precise requirements on the building mass and orientation. For example, the top floor could only contain common spaces for all residents. As an additional goal, the project sought to develop architectural, production, and technical solutions that would make the price of wooden construction competitive with concrete – and succeeded in doing so.

Technical solutions

The building is equipped with automatic extinguishing equipment (sprinklers) and meets the requirements of fire class P2. To increase resident safety, the stairwells have smoke ventilation windows that can be activated collectively from the ground floor.

Prefabricated solid wood volumetric elements were used for the building frame, and CLT planar elements for the corridors. The buildings also have prefabricated bathrooms, whereas the light partition walls are mostly drywall-covered pole frames.

For the roof, a latticework assembly with a bituminous covering was assembled on site and then hoisted onto the top floor’s volumetric elements. Blown wool thermal insulation in the roof raises the building’s energy efficiency to energy class B, and district heating and water-based radiant floor heating complement the other technical solutions.

The construction project

Thanks to the careful planning and efficient construction methods, construction kept to the planned schedule The design process began in January 2021, with construction kicking off in April 2022. Element installation started in October 2022, and the entire building was complete by May 2023.

The key lesson learned was that it does indeed make sense to maximise prefabrication when building a wooden apartment building. To avoid unnecessary waiting, it is also important to carefully plan the installation and connection of building technology and the construction of common spaces.

Overall, the construction process was smooth, and the planned solutions were successful.

CREDITS

Architect and lead designer: Antti Heikkilä architect SAFA, Arkkitehtitoimisto Antti Heikkilä Oy
Antti Heikkilä is an architect with expertise in exceptionally demanding construction design and lead design projects, with examples ranging from apartment buildings to small houses. He is the main owner of the architectural office that bears his name. The design references of his office also include several wooden apartment buildings. Antti Heikkilä also has extensive experience in planning public projects, offices, and land use, and in project development and construction.