Skellefteå now has one of the world’s tallest wooden buildings.
nosing 20 storeys above the low-rise skyline, Skellefteå has a fitting monument to its carbon-cutting credentials. The Sara Cultural Centre and its towering Wood Hotel stand as beacons of what it is possible to do with timber – and store about 9,000 tonnes of carbon from the atmosphere in the process.
The technology behind it is surprisingly simple. The two main materials are glued laminated timber (glulam) and cross-laminated timber (CLT). The former is made from layers of lumber bonded together, with the grain running in the same direction, giving it a higher load-bearing capacity than both steel and concrete, relative to its weight. It is ideal for columns and beams, and forms the structural bones of the cultural centre, which is home to two theatres, a museum, an art gallery and a library.
The “self-finish” nature of structural mass timber, which can simply be left exposed, means that the tower was incredibly quick to build, doing away with the usual wet trades of plastering and decorating. A whole year was saved by using wood, compared with steel and concrete, with a storey completed every two days. The number of truck deliveries was also reduced by about 90%, with practically zero waste on site. Like bits of a giant balsa-wood model, the pieces came from factories ready to be bolted together, some in panels 27 metres long, while the trees were harvested from within a 60km radius of the site – and have all since been replenished. Just like the region’s forest-foraged restaurant menus, this is meaningful local sourcing rather than a green veneer.
The climate isn’t the only beneficiary. Building in wood seems to have a positive effect on construction workers. While a normal building site is a noisy, toxic place of fumes and dust, a timber one is a picture of serenity. “The people building this would never go back to steel and concrete,” says Jesper Åkerlund from contractor Holmen, which is analysing improvements to its workforce’s mental health following the project.