Residents queuing for Finland’s first log-based apartment building, Hirsihovi in Pudasjärvi
Residents queuing for Finland’s first log-based apartment building, Hirsihovi in Pudasjärvi
The autumn of 2021 marked the completion of Finland’s first two log-based apartment buildings in Pudasjärvi, the carbon footprint of which is small. The log material can be seen in the buildings’ facades and well-lit apartments, and the design of the hybrid buildings also utilises concrete elements in a smart way. Residents are particularly appreciative of the quietness of the rental apartments, and demand for these apartments has been high.
Pudasjärvi is Finland’s log capital, favouring Finnish logs in construction projects. In the autumn of 2021, two four-storey hybrid buildings featuring Finnish wood to complement the load-bearing concrete structures were completed in the city centre. The objective was to develop a modern log-based apartment building solution that would be easy to replicate in other locations.
“So far, logs have been used in Pudasjärvi to build schools and hotels, which can also be seen as log-based works of art. However, utilising wood construction in the battle against climate change also requires a bulk product that can easily be brought to the market on a larger scale,” comments Managing Director Jouko Väänänen from Pudasjärven Vuokratalot Oy.
The use of log and concrete structures was given thought at Hirsihovi through the strengths of both. Väänänen says that a wooden intermediate floor can be a risky solution in terms of both sound insulation and water damage. “Easy maintenance also affects the carbon footprint of the building, so we chose to use concrete hollow-core slabs for the intermediate floors,” he explains. The wet areas and the walls between apartments were also made from concrete. “However, the exterior walls are where logs show their strengths.”
Making innovative hybrid structures work
Hirsihovi is one of Finland’s first multi-storey log buildings, so the entire project group had many new challenges to overcome. “Our job was to reconcile concrete and log structures and production-related boundary conditions so that the end result would be sensible and cost-efficient,” says Sweco’s structural engineering specialist Tuomas Jaakkola.
One new solution was to connect the intermediate floors to the exterior log wall so tightly that the end result meets fire protection and sound insulation requirements. Jouko Väänänen says that the construction supervisor was expecting major additional expenses throughout the entire project. “They never came, though, as we were able to secure fire safety without a sprinkler system and so forth.”
The sound insulation of the building has also generated positive feedback. “The sound insulation was given a good score in impartial measurements, and disabled residents with high sensitivity to sound have also applauded the quietness of the apartments,” Väänänen says. “The fine end result is indicative of open design and careful construction.”
Logs are suited for urban construction
The architectural design of Hirsihovi was created by Linja Arkkitehdit, currently part of Sweco. The original plan was to have three buildings on the property, but the scheme was ultimately changed into two larger buildings. “This way, the buildings frame the street in a natural way and support the cityscape of the Pudasjärvi city centre,” explains Sweco’s Responsible Construction Planner Anu Kortet. The apartments were designed to be relatively small in order to make them well suited for seniors moving to the city centre from a detached house. “15 of the rental apartments are also designated as Keva apartments for special groups.”
The unsettling SmartLog™ logs developed by Kontiotuote made it easier to combine log structures with concrete elements. The SmartLog™ material also supported the architects’ vision of a classically simple and timeless visual appearance. “The low-key design language of modern logs is well suited for urban apartment building construction,” comments Principal Designer Jaakko Kallio-Koski from the Finnish Association of Architects SAFA. “For example, Hirsihovi does not have any cross corners typically found in conventional log buildings.”
The people of Pudasjärvi are happy with how Hirsihovi has elevated the cityscape and bumped up the reputation of the region. Residents have also been enjoying the apartments, which feature log structures inside as well, in the facade and partition walls. “The apartments have proven so popular that there is a long queue for them. We need another pair of similar buildings in the city centre!” Väänänen comments.
The cooperation between Pudasjärven Vuokratalot, Kontiotuote and Sweco will next continue with a project to build 20 log-based terraced houses in Syöte. “Our objective is to provide seasonal workers with high-quality but reasonably priced apartments,” Väänänen says. The partners are already familiar with each other, so they already know that things will work. “It’s great to work in such a good atmosphere.”