Kaijonharju kindergarten

As the client, the city of Oulu established ambitious objectives for the Kaijonharju kindergarten: the pilot building was conceptualized from the outset with the child’s perspective and long-term well-being at the forefront. At the Kaijonharju kindergarten, children were prioritized through views, spaces, and material selections. In this pilot project, methods to minimize the chemical load were also investigated.

Read the article in Finnish here.

Kaijonharju Kindergarten is a small, five-group daycare center located in the Kaijonharju district of Oulu, near the Linnanmaa campus. It is constructed using Cross Laminated Timber (CLT).

The project’s client, Oulun Tilapalvelut, outlined the project’s objectives at the outset. These objectives were to achieve low-carbon emissions, high-quality wooden architecture suitable for northern conditions, and to minimize the chemical load in facilities intended for children.

During the drafting phase, the building’s surroundings, paths, and views were analyzed. The intention was for the building to play a prominent role in its surroundings. The building’s shape deviates significantly from the surrounding structures, making it a small-scale landmark along the area’s light traffic routes.

The design framework was established by the 1980s site plan, which we did not want to deviate from due to the project’s timeline. Harmonizing the premises with the building rights permitted by the plan led to efficient and multipurpose use of the space. Several options were explored for space solutions, and a solution was sought where the children’s spaces face the parade ground on the yard side and the staff spaces with auxiliary spaces are located in the outer ring.

The project aimed to create a high-quality, stimulating, and small-scale environment for children. Unique features include the extensive use of wood in both indoor and outdoor spaces and consideration of northern weather and light conditions. The building’s P3 fire class allowed for the extensive use of wood on visible surfaces.

Even in bad weather, children can play under the large roof of a sheltered courtyard pocket

The building mass consists of four single-store, parallel gable-roofed masses that form a small-scale environment around them. The kindergarten accommodates five daycare groups, ranging from toddlers to preschool children. In the building’s heart lies a luminous canteen that opens southward through expansive glass surfaces. It also enjoys a vista of northern Kaijonraitti. Adjacent to the canteen, a sheltered garden alcove unfolds, offering a space for play even in inclement weather beneath the expansive canopy. This area is also well-suited for hosting the kindergarten’s outdoor events.

The children’s group spaces occupy the most favorable locations on the yard side, facing sunny air directions. Maintenance and auxiliary facilities are situated on the north side. Three shared spaces are positioned adjacent to the canteen, allowing all groups to utilize them. The shared spaces are designed for diverse purposes, such as home play and reading sessions.

Cabinet beds in rest areas allow for other activities in the same space outside of resting hours.

Carbon footprint comparison guiding the design

CLT was chosen as the framing material based on a comprehensive assessment of its carbon footprint and handprint. The solid wooden load-bearing frame effectively sequesters carbon, while the external thermal insulation contributes to energy efficiency. The carbon footprint was also evaluated in terms of surface materials and by considering energy solutions.

Research indicates that the carbon footprint of wood construction can be up to six times lower compared to concrete construction. When selecting interior materials, we paid particular attention to minimizing the presence of harmful chemicals and choosing materials with low environmental impact.

Naturalness and reduction of the chemical load in outdoor spaces

The existing large pine trees on the plot were retained as part of the yard design. The pine trees provide natural shade areas throughout the yard and create a harmonious connection between the kindergarten yard and the surrounding environment. Additional lighting has been added to accentuate the beauty of these trees.

For the yard’s play equipment and safety surfaces, we prioritized natural and environmentally friendly options that are free from potentially harmful chemicals. Safety chips and the Ecosurface platform were selected as safe and eco-friendly alternatives. The yard boasts a lusher vegetation compared to a typical kindergarten yard, further enhancing its natural ambiance. The play equipment is primarily made from wood, complementing the surrounding greenery.

Materials specifically designed to minimize chemical exposure were selected for the Kaijonharju daycare center. The design was guided by, among other considerations, a no-shoes policy in kindergarten spaces. The CLT interior walls were treated with light log wax, preserving the peaceful tone of the wooden surfaces for years to come. Cork serves as the primary floor material in the nursery. Textile carpet is used in children’s rest areas and distribution zones. Laminate-coated chipboard was chosen for fixed furniture in children’s spaces, while stainless steel serves as the surface material. Loose furniture primarily consists of solid wood, laminate, metal, and upholstery fabrics. By prioritizing chemical-load reduction when selecting interior materials, a safe and healthy environment for users can be achieved.

Nature-themed color schemes help to orientate the premises

The daycare center’s floor plan divides the children’s spaces into three distinct entities, differentiated not only by their layout but also by color themes. The shades of the premises draw inspiration from the natural color palette – yellow ochre, red clay, and green lichen spaces aid children in orienting themselves within their respective areas. In common spaces, the tonal themes converge. In the dining room, they are echoed as subtle accents in fixed furniture, loose furniture, and interior lighting. In the three shared spaces, the colors are revisited in a monochromatic theme, where the group’s color tone is carried through to all elements of the space.

The bathroom furniture blends beautifully with the shades of the surface materials. The built-in furniture is sized for children.

Shades are prominently featured in children’s spaces, with the colors repeated in both surface materials and fixed and loose furniture. Boldly applied, thoughtfully selected colors infuse the spaces with life and joy, while wood together with calming neutral greige tones provides balance and composure. In addition to the colors and materials, the nature theme extends to the group names chosen by the client. Reflecting the names, the glass doors of the group rooms are adorned with depictions of pinecones, white flowers, spruce buds, willow catkins, and rowan berries.

The design took into account the reduction of the chemical load

From the very outset of the project, the client’s directive was to meticulously plan and execute the Kaijonharju daycare center with a keen focus on minimizing chemical exposure. The client provided guidelines for the interior design, specifying harmful substances to be either avoided or prohibited altogether. These guidelines were meticulously followed in the selection of surface materials, surface treatments, fastening methods, and furniture. The designer adhered to the client’s goals, meticulously planning the project in accordance with the given instructions

The investigation of materials for the site demanded a deeper understanding of the chemical properties of various materials than is typically required. Over the course of the project, the designers gained invaluable expertise in reducing chemical exposure, both in architectural and spatial planning.

Indoor air quality is influenced by various factors, including compounds emitted from building materials or particles released by them. The effects of these compounds on human health are a topic of ongoing research. While studies have been conducted and have revealed the negative health and environmental impacts of certain materials or their constituents, there is still a significant lack of information. The effects of many chemicals on health and the environment remain unclear.

Considering the reduction of chemical exposure during the design process is crucial, particularly in the design of spaces intended for children. Compounds that evaporate from materials can have a profound impact on the well-being of building occupants, especially over the long term. Children and young people, whose development is still ongoing, are particularly sensitive to the effects of chemicals. By engaging in responsible planning, safer than usual conditions can be achieved.

Considering the chemical load in the design

Obtaining information about the indoor air effects of building materials is possible but requires time and familiarity with the subject matter. Certificates issued to products are a positive step, but the comparability of different certificates can often be challenging, as they may be based on different measurement standards and units. There may also be differences in certifications between different countries – for instance, a product labeled with the Joutsenmerkki (Swan Mark certificate) in Sweden may not necessarily be Joutsenmerkki -certified in Finland.

The complexity of comprehensively reviewing the entire material chain and its associated components presents its own set of challenges. For example, information on floor covering materials and their indoor air effects may be readily available, with the product advertised as meeting the required criteria. However, the issue may lie with the moisture barrier and adhesives used to affix the floor, which may not meet the necessary standards. In many cases, the manufacturer of the floor differs from the manufacturer of the fasteners, resulting in fragmented information that can be cumbersome to assemble. The designer is therefore obligated to exercise critical thinking and examine the entire process chain.

Healthy and safe materials often exhibit simpler structures and ingredients compared to their supposedly more harmful counterparts. Generally, natural materials represent superior options to synthetic ones. Recycling and reusing simpler materials are also often more efficient than materials composed of multiple components. Recycling materials, on the other hand, positively impacts the carbon footprint of construction. As a result, the effects of indoor air quality and carbon emissions of building materials should be considered in tandem, rather than treated as entirely separate entities. However, when striving for a circular economy and material reuse, it is crucial to ensure that harmful substances do not re-enter the cycle.

In material selection, materials that encounter indoor air and users are held to a higher standard of scrutiny. During the selection process for the Kaijonharju kindergarten, materials were chosen based on low or nonexistent emissions of the following substances: formaldehyde, phthalates, flame retardants, volatile organic compounds (VOCs), polyvinyl chloride (PVC), per- and polyfluoroalkyl substances (PFAS), plastics, antibacterial substances, and materials (excluding healthcare facilities), nanomaterials, and carcinogenic substances. In addition to these factors, consideration was given to the use of recycled materials.

In the pursuit of eliminating harmful substances, it is not sufficient to solely examine surface materials; the evaluation must also encompass materials utilized for fastening, the materials’ lifespan, maintenance, and cleaning. The most desirable materials are those that are intrinsically low-emitting and require minimal use of harmful chemicals for treatment and cleaning.


The understanding of the climatic, environmental, and indoor air emissions and effects of building materials is continually evolving. Clients, designers, and those involved in the construction industry have the opportunity and responsibility to accelerate the development of a more environmentally and health-conscious built environment by demanding information and better solutions from industry players. The client’s role is emphasized in the early stages of the project when establishing goals. By eliminating harmful chemicals, we aim to surpass the prevailing standards and requirements. Thus, we strive to create a healthier future not only for ourselves but also for future generations.

The planning of the Kaijonharju daycare center commenced in 2021, construction commenced in 2022, and the site was completed by the end of 2023. The building was erected under weather protection up to the water roof and facade cladding. CLT elementing significantly accelerated the construction schedule, enabling the building to be completed ahead of schedule.

The solutions piloted in the project regarding low carbon and chemical load reduction will also be implemented in other Oulun Tilapalvelut projects.


MUUAN was responsible for the main, architecture and interior design of the project. Worked as partners for structural design, Suunnittelu Laukka and for yard design, HELMA.
The main contractor was the Construction company Observo Oy. The CLT elements were supplied by Crosslam and the installation was carried out by Massiwe.

Project in brief

Kaijonharju kindergarten

  • Valmistumisvuosi | 2023
  • Photographs | Marc Goodwin
  • Text | Interior Architect Venla Tiainen and Architect SAFA Tiina Antinoja, MUUAN Oy