An educational example of sustainable design14 Jan 2020
Large areas of glass, plenty of daylight and open views are the foundations of the greenest school in Norway. Thanks to the use of natural materials and bold environmental choices the award-winning building that houses the new Horten high school sets the standard for the future.
Light and energy-efficient
In 2015, Vestfold County Municipality decided to become the greenest county in Norway. It was therefore natural to take a strong environmental profile when the time came to build a new high school in Horten. The municipality took the ambitious decision to aim for an environmental classification system that integrates sustainability at every level.
“It’s been an exciting process. Everyone was determined to find the right environmental and architectural solutions, as well as meeting the wishes of the developer and users,” says architect Grethe Brox-Nilsen from LINK Arkitektur.
The building has four floors plus a basement and utility room on the roof, an arrangement that meets many of the requirements for logistics, layout and access. It was also important to preserve a feeling of closeness to the park outside.
There was a desire to draw the neighbouring park into the building and create a strong sense of connection with the natural surroundings of the school. This idea is realised by linking up with paths from the historic area of the park so that they continue right through the building. The school opens on to the park in a way that makes the building feel inclusive and open.
“The street winds through the building and connects us to the rest of the park. The glass facades provide lots of daylight and open views. You can orient yourself in relation to your surroundings at any time and feel in touch with the landscape around the school,” explains Brox-Nilsen.
A place where sustainability and aesthetics meet
Horten high school meets both passive house and energy-positive building standards. The building has 3,700 m2 of solar panels, 13 geothermal wells, waterborne heating and impressive levels of insulation in the walls and ceilings. Strict requirements for toxin levels, transport emissions, recycling efficiency and draughtproofing meant that all materials had to be evaluated carefully.
“We thought a lot about how we could achieve this. There were only a few other buildings we could use for reference, and this is a building that had to meet considerably higher demands than any technical standard. One such question was what material should we use if we can’t use concrete? We ended up with solid wood,” says the architect.
The palette of materials is based on environmentally friendly choices, and the exterior walls, floors and main staircase are built of wood. Inside, oak and oak parquet are used. Outside, the architect has chosen untreated ore-pine. The wood makes a striking contrast with the large areas of glass supported by recyclable aluminium profiles from Hydro-owned Sapa. The result is a compact and warm building with wonderful light.
“It was a challenge to make full use of daylight and the views in such a compact building, especially for classrooms and other utility spaces that face on to the atrium,” Brox-Nilsen admits.
The answer was to create balconies on the upper floors on one side of the atrium. The idea is that every part of the building should lead to the atrium, which is also the main common space in the school. Each department in the school is just a short distance from this space, which makes it easy to orient oneself and helps to create a sense of community.
Building Information Modelling (BIM) was used during the design of the school. BIM creates digital 3D models of buildings and makes it possible to visualize, plan, do calculations and coordinate the building process, as well as improving and simplifying collaboration between multidisciplinary teams. Brox-Nilsen explains:
“BIM was part of the design process. A composite model was used to check for clashes between the different structures, and the model was also used to get a visual overview in 3D. Workstations were set up on the construction site so that the model could be examined in detail.”
Everything begins in the heart room
At the school, the atrium is known as the “heart room”. It is a large, open space that is designed to welcome everyone – students and teachers. It also forms the main artery of the building.
“One of the key visions for the school was to create this heart room, a space where students would feel comfortable and which would discourage exclusion,” says Runar Bekkhus, who represents the developer, Vestfold County Municipality.
The room is open and welcoming, and has dedicated zones for socializing and working. The large glass facades that form the entrances from the east and west give the entire school a transparent and inviting impression. A large oak staircase provides vertical communication within the atrium.
“The students file down in a long line to reach the heart room. During breaks, they wind down the stairs like a snake towards the heart of the building. The heart room turned out at least as good as was imagined,” says Bekkhus
But using such large expanses of glass as well as a glazed roof presented a challenge in keeping CO2 emissions low. One of the consequences was that an extra five centimetres of insulation had to be added to the outer walls. It would have been difficult to create the large glass facades without the insulating properties of Sapa’s aluminium profiles.
Horten high school is designed with sustainability as a fundamental priority throughout the value chain. This guided everything, from the choice of materials and energy solutions, to recycling waste during construction. The overall result was a reduction in greenhouse gas emissions of at least 40 percent compared to a reference building.
Bekkhus explains that a lot of effort was put into recycling waste during construction.
“We even cut open vacuum bags and sorted the contents,” he says.
Horten high school won a 2019 BREEAM Award for public sector projects. BREEAM is the world’s leading environmental classification system for construction. The award confirms that the new Horten high school is the greenest school in Norway.
“It’s important to understand how architecture affects the environment. We were totally committed to sustainability on this project. It also means that we have created something that will last for generations,” concludes architect Brox-Nilsen.
Umbra Produkter AS, Norway
Glass facades: Sapa 4150 SX (available with Hydro CIRCAL, containing at least 75% recycled post-consumer scrap)
Aluminium fire doors: Sapa 2086
Fixed internal aluminium windows: Sapa 1050