If you ask people what they envision when they think of futuristic cities, you might receive answers about vast landscapes of steel and glass connected by AI-driven flying cars.
But what if the real answer is much simpler? What if cities of the future are made out of wood?
Skellefteå, a town in the far north of Sweden, is putting this idea to the test. The recently completed Sara Kulturhaus and Wood Hotel is one of the tallest wooden buildings in the world. Standing at 20 storeys tall, it’s undoubtedly a skyscraper by wooden standards.
In a world of climate-conscious marketing, tree-planting is the hero and tree-cutting the villain. But in the proper contexts and with thoughtful forest management strategies, timber buildings might be one of the best models for regenerative cities of the future.
A sustainable building for a sustainable community
Skellefteå is the perfect place to construct a wooden skyscraper. The community already runs on 100% renewable energy derived from hydropower and wind. Not only that, it recycles 120,000 tonnes of electronic waste a year, feeding the excess processing heat back into the city’s heating system.
Given the city’s standing commitment to sustainability, it’s fitting that the Sara Kulturhaus and Wood Hotel is estimated to store around 9,000 tonnes of atmospheric carbon within its walls.
The wooden skyscraper gives a new meaning to “sourcing locally.” All 12,200 cubic meters of wood used in the construction came from forests within 60 kilometres of the city. Furthermore, all of the cut trees have since been replanted.
But the skyscraper’s sustainability aspects go beyond the initial construction. The building doesn’t just consume energy; it produces it as well. Solar panels, batteries, and a heat pump all contribute to the building’s energy needs, monitored and adjusted by artificial intelligence. Whenever excess energy is produced, it gets stored in on-site batteries or passed on to the city’s power grid.
How is the wooden skyscraper built?
Two primary wood materials are used in the construction: glued laminated timber (glulam) and cross-laminated timber (CLT).
Glulam is made by gluing layers of lumber together, with the grain running in the same direction. It’s durable, water-resistant, and incredibly strong. In proportion to its weight, it has a higher load-bearing capacity than steel or concrete. This makes it ideal for columns and beams, and it’s used in the cultural centre to support the wide-open spaces for two theatres, an art gallery, a library, and a museum.
CLT is similar to plywood. It’s made by stacking layers of wood at right-angles and gluing them together. The resulting solid slabs are strong in every direction, so they’re perfect for floor slabs, walls, beams, and columns. Even the elevator shafts are made from CLT.
While the majority of the construction is wood, concrete and steel still feature in certain areas. For example, there are some steel trusses under the hotel rooms, and the top floors are built with concrete slabs to keep the building from swaying too much in the wind.
Using wood over other construction materials has a few advantages. For one thing, it’s far lighter and more flexible than concrete or steel. In addition, it has excellent moisture control properties and creates a softer, more pleasant indoor environment. In terms of fire risk, CLT burns very slowly, is coated with a fire retardant, and is designed with a sacrificial char layer to protect the structure for up to two hours or until the fire services arrive.
Another significant advantage to working with wood is the construction speed. Astonishingly, each storey only took two days to complete. The prefabricated pieces arrived from the factory ready to be assembled like a giant model. Since the wooden surfaces were left with a natural finish, no painting or plastering was necessary. It’s estimated that up to a year was shaved off the construction time compared to industry standards using concrete or steel.
It’s better for workers and visitors, too
After working with wood on a project of this scale, many of the construction workers didn’t want to go back to working with concrete and steel. Instead of a noisy environment filled with toxic dust and fumes, the timber-based workplace was healthier and more peaceful.
Wood is more natural in every sense. It has a calming effect on people’s moods and acts as a softening acoustic device. According to Fransesca Quartey, director of the Västerbotten regional theatre, “There is a softness to the whole place. It just makes you feel happy.”
The future of regenerative cities
Will more cities follow in Skellefteå’s footsteps? It’s hard to say. The construction industry remains firmly entrenched in its approach to building megacities and new infrastructure. When it comes to construction materials, profitability and convenience usually take priority over sustainability and consequences to human health. And it’s unclear whether other countries could effectively manage their timber sources without further deforestation.
However, there is hope that more pioneers in modern wood construction will keep pushing the industry forward. Wooden buildings can store carbon, be constructed faster, preserve ecosystems, and positively benefit human health. If we follow Skellefteå’s example, then the sustainable cities of the future will showcase wood in all its glory.