Solid wood prominent in all the facilities of Isokuusi day care centre and school

Construction is currently underway in Vuores, Tampere, on one of the largest wooden residential areas in Finland, with the wood construction trend also reflected in the day care centre and school designed for the area. Combining wood, concrete and steel in various ways brings out the best in each material.

The City of Tampere is promoting low-carbon construction with its Carbon Neutral Tampere 2030 roadmap. In 2020, the City commissioned a report on the total emissions generated by construction activities from Gaia , a consultancy that has since become a part of Sweco. According to the report, the use of concrete accounts for approximately half of the total emissions from construction. As such, Tampere is taking the promotion of wood construction very seriously. In fact, the City has been named a Pioneer in Public Wood Construction by the Finnish Ministry of the Environment and Motiva in recognition of its efforts.

The promotion of wood construction is especially apparent in the Isokuusi area of the city district of Vuores, which saw the completion of the new two-storey Isokuusi day care centre and school for over 300 children at the start of 2022. “Isokuusi is developing into one of the largest wooden residential areas in Finland, with the new school and day care centre building serving as a trailblazer in terms of the City’s low-carbon construction efforts,” states Construction Supervisor Juha Koskinen from the City of Tampere’s Tilapalvelut unit.

Cooperation started with the wooden Hippos day care centre

The structural design of the Isokuusi school and day care centre was carried out utilising solutions that Sweco had previously employed in its first public building construction project with Tampereen Tilapalvelut to be built out of CLT elements: the wooden Hippos day care centre.

“The structural design of Hippos taught us a great deal about utilising wood alongside other materials,” says Department Manager Petri Kokkonen from Sweco’s wood construction department. Cooperation in the Isokuusi project was further facilitated by the involvement of the same contractor as in the Hippos project. “We were on the same page from the get-go and were able to provide on-site support during construction.”

From the project supervisor’s perspective, it is paramount for project plans to be up to date, feasible and sufficiently detailed, so that they can be utilised on-site. “Sweco provided us with excellent service in that regard!” states Koskinen from the Tilapalvelut unit.

Smart combinations of different materials

The building design includes a large number of hybrid solutions, with the material diversity visible particularly in the access balconies, ceiling structures and yard buildings. The design also makes extensive and varied use of wooden structures.

“The intermediate floors are made out of LVL box slab elements, while the load-bearing intermediate and exterior walls consist of large CLT elements that are also visible in nearly all of the indoor facilities,” Kokkonen says. In terms of its thermal insulation properties, CLT is comparable to timber, as a result of which the building did not need any other heat insulation besides the 260-millimetre CLT exterior walls. The diverse roof was constructed out of nail plate roof trusses. “The roof structure includes approximately 200 of these.”

Other materials were also utilised in places where their properties provide the greatest benefits. For example, the access balconies feature weather-resistant concrete slabs and steel pillars. Concrete was also used in the building’s wet areas and as the intermediate floor medium in HVAC rooms. “The wood theme was also incorporated into visible concrete surfaces through board forming, giving them a wood-like appearance.”

The open, accessible and multi-use facilities of the building can be combined in various ways with easily adjustable partitions. “We paid particular attention to the acoustical solutions of the building and the acoustics of individual facilities,” Kokkonen says. Moisture control during construction was carried out by using a large tent. “It protected the building until the roof was completed.”