The energy-efficient apartment building was designed from wooden space elements

Haagan Artturi is a solid wood small apartment building, the design of which was guided by the efficiency and sustainability of construction. On a small-sized plot, a wooden apartment building was built from CLT space elements. Geothermal heat was chosen as the low-emission form of heating.

Completed in summer 2023 in Helsinki, As Oy Haagan Artturi represents modern wooden residential construction. The low-rise building consists of 11 apartments on 4 floors. The goal was to create a healthy and energy-efficient living environment on a fast schedule, which is why the project was implemented with CLT space elements manufactured by Timberpoint that are insulated and clad from the outside.

“Each floor was assembled from seven modules, which were almost finished at the factory,” says Susanna Friman, Group Manager at Sweco. On site, the modules were simply connected with steel parts and the necessary building services connections were made to them.

Friman felt that the frame solution was particularly suitable for a tiny plot that had been parcelled from the plot of an adjacent apartment building. “In infill construction, it is very useful that the spatial elements can just be lifted into place.”

Space element construction ensures high-quality indoor conditions for building users already on site. “The elements are assembled at the factory under controlled conditions and brought to the site protected from the weather, so their exposure to weather conditions is minimal.”

From the point of view of structural design, the overall design of space elements requires a unique attitude. In order for large entities to be connected smoothly on site, detail design must be very precise. “Not all parts can be accessed on site anymore, so we have to plan in advance not only the modules, but also their assembly sequence and fastenings.”

Ground cooling is free energy for the housing company

In addition to structural design, Sweco was responsible for the HVAC, electrical, building automation and sprinkler design of the apartment building, as well as ground surveys. Energy certificates were also drawn up for the site, and the goal was energy class A.

“Modularity did not limit the technology choices, and the client gave us quite free rein to choose the most functional solutions,” says Risto-Matti Remes, Sweco’s Head of HVAC Department. Sweco’s experts carried out condition calculations at the site and modelled the need for geothermal wells. “The geothermal heat chosen as the heating method clearly had the best market value.”

Two geothermal wells and water-circulating underfloor heating ensure that the conditions in both living and wet rooms remain pleasant all year round. The same system takes care of the cooling of the apartments, which is of great importance for the health and comfort of residents in hot summers. Ground cooling is free energy for the housing company.

“The same piping is used for cooling as for heating, so there are no extra costs for the housing company and materials are also saved,” Remes says. In addition, there are solar panels on the roof of the apartment building and charging points for electric cars in all parking spaces.

Due to the fire safety of wooden structures, the entire building was connected to the water sprinkler system. The ventilation units are apartment-specific, and residents have access to apartment displays that are connected to the building’s building automation system.

“Residents can control ventilation and temperature, for example,” Remes says. In addition to outdoor and indoor temperatures, the apartment displays can monitor the consumption of cold and hot domestic water. “The more you know about your own consumption, the more you want to influence it.”

Picture: Puurakentajat/Mika Huisman, Decopic