Koivukylä daycare centre

Finland’s largest log daycare centre opened to the public in September 2022 in the Koivukylä district of Vantaa. An assessment of the carbon footprint was part of the bidding process.

Read the article in Finnish here.

Designed to host 224 children, the daycare centre showcases the concept that the City of Vantaa has for its daycare facilities. The site is located in Koivukylä next to Helenanpuisto Park on an open, wide slope with an area of 14,330 m2. As it is nestled on a slope in the plot’s northern section, the building has three masses of one and two storeys that follow the flow of the slope. Some of the plot’s green areas have been left in their natural state, and the forest in Helenanpuisto Park also offers children a place to play.

The drop off area for the facility is separated from the yard by a small-scale wooden entranceway and gate structure. The drop off area leads to a lower yard, which also serves as a playground for 1 to 3 year olds. The 3 to 6 year olds have a playground of their own in an upper yard. A landscaped slope serves to separate these lower and upper yards while the maintenance area on the north side is set off on its own. The building entrances are clearly marked by staircases and entrance canopies. There is a larger entrance staircase on the east side, and a staircase carved into the ground leads from the middle to the first floor yard. Thanks to the slope, the yard feels spacious and has open views of its surroundings yet maintains a clear, easily manageable layout.

The building’s design builds off of the traditional of log construction with its uncomplicated masses, wall surfaces, and roof and eave structure. The distribution of the logs determines where windows can be placed and how high the ceilings can be. The building’s exterior walls are made from logs, while the intermediate floors are mostly CLT. The roof structure is made from CLT panels and wooden lattices, and the load-bearing pillars and beams are made from glulam. The placement of the windows and their varying sizes break up the uniformity of the complex. Natural light streams into the interiors from the large windows and smaller upper windows, while the lower windows and peepholes makes things child-size and introduce a sense of playfulness that reflects the building’s purpose.

The building interior is divided between spaces for children and common, support and functional spaces. The functional spaces include a canteen and gymnasium in addition to the facilities for daycare groups. All rooms are one storey high. The City of Vantaa has its own spatial concept for daycare centres, which served as a basis for the interior design. This concept calls for homerooms shared by two daycare groups each. The two groups have their own play areas but share a common quiet space. The daycare centre has eight homerooms, which results in a total of sixteen groups. For added privacy, the shared quiet spaces can be divided using folding doors made from felt and wood panels. Wood was used for the interior doors and windows with the inside components tinted to a light shade. The interiors use a colour palate with natural shades ranging from brown to green and yellow.

The carbon footprint as part of the bidding process

The log daycare centre in Koivukylä is an example of Vantaa’s current policy of building schools and daycare centres from wood whenever possible. While the original plan was to be carbon negative, compromises had to be made due to late-breaking changes, including a request to increase the capacity of the civil defence shelter. The end result is still remarkably low-carbon.

Energy-efficiency is everywhere in the Koivukylä daycare centre: cost reductions are built in with water-saving taps, smart building technology, energy-efficient lighting, ground source heat pumps, and solar electricity. In the city’s tendering process, the received bids were assessed for their carbon footprints and the load during construction. The Hoivarakentajat Oy and Honkarakenne Oyj proposal had the lowest carbon footprint compared to others. The proposal included total carbon dioxide emissions of 118 kg/m2 coming from the production of raw materials, transportation and pre-fabrication at the factory. This is significantly lower than the average for buildings (250 kg/m2).

Technical solutions

The building is fire class P2 and has sprinklers, which means a separate fire protection system was not needed for the log frame. The fire compartmentalisation is done by floor.

A spring frame was added under the roof ’s CLT slab to manage the lateral movement of sound in the children’s quiet rest and activity areas.

A ceiling mounted structure with a wood fibreboard surface has been installed to enhance room acoustics, and the folding doors in the activity areas also have a felt surface for the same reason.

The construction project

Site design began with a sketch in spring 2021, with the main design being completed in June 2021. The application for a building permit was submitted in June 2021, and construction kicked off in mid-August 2021. Log frame installation began in January 2022, and the site was completed in September 2022.

The project was done under a turnkey contract. In this case, the turnkey contractor had a construction subcontractor and building technology subcontractors but their own project manager and project engineer. The key lessons from this project involved making the different materials work together and managing the plethora of structural details.

CREDITS

Arkkitehtuuri Oy Lehtinen Miettunen is an architectural firm operating in Hämeenlinna. The office’s design targets include residential buildings, kindergartens and service- and carebuildings, as well as public buildings. The office was founded in 2003. The partners are architects Sakari Miettunen and Lasse Lehtinen, 6-8 designers work in the office. The office offers BIM-based architectural design. Sakari Miettunen has graduated as an architect from the University of Tampere and works as the architect and chief designer of the projects.