Børnegården Bison: a circular kindergarten built from recycled materials
With a philosophy of building as light and as little as possible, Sweco Architects focused on creating a shape and construction with minimal carbon footprint. Read about the ideas behind Børnegården Bison, a circular kindergarten in Gammel Rye, Denmark.
The building is entirely round and constructed from wood. Here's a brief description of the Børnegården Bison kindergarten in Gammel Rye, Denmark, which provides the setting for 130 children aged 0-6 every day.
Behind the special construction is Sweco, acting as architect and consulting engineer on the project, which was tasked with creating a contemporary daycare institution with minimal carbon footprint. A task that required a slightly different approach. Tina Lind, architect and creative director for learning and leisure at Sweco, says:
"When building sustainably and when building daycare facilities, it's crucial to build as efficiently as possible with a very low gross/net factor, where most of the floor space is reserved for the children. The round form achieves that, as the circle is the most compact shape available and the corridor areas can be reduced to a minimum." She goes on to explain:
"In recent years, we've become more skilled at building wooden structures, which is why it was natural for us to look in that direction, as it requires less CO2 than other alternatives. We chose the round shape because it is so efficient and presents as little facade as possible. You could say that this is pragmatism meeting the dream of a circular building," says Tina Lind.
Familiar materials in a new setting
Throughout the process, sustainability has been a design parameter at the same level as the educational concept. LCA screenings were performed regularly for the project, and variance studies have been carried out in connection with the choice of materials. There was a continuous balancing act between materials with a low carbon footprint and with low operating and maintenance costs.
" To keep our footprint as low as possible, we needed to explore every option. One of the things that means here was that we looked for existing materials we could reuse in the new project," says Tina Lind and continues:
" For example, we received a lot of recycled red bricks from an old Per Kirkeby monument and another 3,800 recycled interior bricks from a building that used to house a dentist at Virring School for the building’s interior walls. In addition, we developed a strategy for fixtures and fittings in which we reused and renovated fixtures from the old institution, so that everything that could be reused has been recycled."
At the developer's request, white-painted Troldtekt acoustic panels based on FUTURECEM™ were installed in the ceiling. FUTURECEM is a cement type with a proportion of calcined clay and limestone filler, which gives a reduced carbon footprint compared to traditional cement and therefore fits in with the architectural firm’s philosophy for the project.
" The developer wanted to create a light, airy building and use Troldtekt to create good acoustics. The solution was the white-painted Troldtekt panels in the ceilings, which bring in light and create a calm contrast to the red bricks," says Tina Lind.
The painted Troldtekt acoustic panels based on FUTURECEM have a carbon footprint that is 34 per cent lower over the entire product life cycle than for painted Troldtekt panels based on traditional white cement.
Sustainability on multiple levels
Looking at it today, Sweco are highly satisfied with the way Børnegården Bison turned out. The final LCA calculation ended at 8.79 kg/CO2/m2/year, and even though it may not sound low today, it should be remembered that Børnehuset Bison was designed in 2022, when the first LCA requirements had not yet entered into force.
"Right from the start, it was a pilot project, and we went into it without knowing how far we could go in terms of the carbon footprint. We’ve had the opportunity to test materials, methods and shapes, and I think we’ve delivered a piece of architectural art – something that’s beautiful, but also attainable. And we can be proud of that."
The lessons learned from this project will take Sweco further – and they will certainly be needed. According to Tina Lind, there is only one way to go when it comes to the carbon footprint of buildings.
"In my experience, we have some ambitious politicians who really want to do something in this area and take it seriously. That puts the pressure on us, and we need to adapt quickly, but it’s really nice to see that implementation of such measures is going so fast, because it is necessary."
But she also raises the question of how we define sustainability in construction:
"Right now, we’re talking a lot about materials with a low climate footprint, and if we calculate this in CO2, as we have done at Børnegården Bison, there are some natural choices to make. Conversely, many of the buildings we build today may not last as long as those we built 100 years ago. A holistic perspective with an eye on both the short-term and long-term environmental footprint is important," she concludes.
But now – and hopefully for many years to come – Børnegården Bison is firmly established in the scenic area of Himmelbjerget.
Tina Lind, architect and creative director for learning and leisure at Sweco Architects
