Move over, concrete and steel! Sustainable construction of high-rises, offices and apartment buildings has paved way for a new generation of ”plyrises”, made from cross-laminated timbers. Naturally, the Nordics take the lead.
Words ILENIA MARTINI
Today’s increasingly important questions around sustainability find the construction industry, which has had to rely on steel and concrete for strength and durability, in the midst of a shift towards solutions that won’t carry the same negative environmental impact as these materials do. As a result of this interest in building materials and energy consumption during construction, our global focus is back on what’s long been recognised as a sustainable material: wood. To be precise: timber.
When it comes to CO2 emissions, manufacturing steel and concrete release incredible amounts of carbon into the atmosphere, wood, on the other hand, captures and stores it away within the timber, making sustainability only one of the many benefits around wood as a material with its natural renewable resource capabilities.
Although familiar and great for the environment, using wood for anything other than apartment buildings with a maximum of four floors is not so straightforward, especially when it comes to high-rises. Wood absorbs moisture from the air and is not fire-resistant as is, but treating it and combining it with other materials can improve its properties. That’s where cross-laminated timber (CLT), which is engineered wood made from glueing layers of solid-sawn timber together to form building blocks, comes into play.
The end result is a lightweight but sturdy material that can be just as strong as concrete but also extremely versatile, quieter and faster to work with — at least according to the experts. It’s through the use of CLT that we get to reimagine the future of construction and understand the appeal of all-wood high-rises or ”plyscrapers” and their relatively small carbon footprint, seen from the work of these architectural firms that are pushing traditional construction boundaries forward, especially when relying on locally sourced and responsibly-forested wood.
Mjøstårnet is located in Brumunddal, a small city with 10,000 residents, about one hour and a half drive north of Oslo. The building, owned by AB Invest and designed by Voll Arkitekter was built using local renewable resources without emitting any additional CO2 for its construction material. As of today, it stands as the tallest timber-frame structure in the world, with its 18 storeys comprising 32 rental apartments, five floors of office space, a restaurant and the 72-room Wood Hotel.
— We want to create a sustainable future using wood, and we hope that this building will inspire others to choose more sustainable and climate-friendly solutions in the years to come. explains Moelven CEO Morten Kristiansen.
— The tower will produce the same amount of energy that it spends. This will be achieved through solar thermal energy, solar cell panelling and heat pumps directed at both earth and water. This whole project will demonstrate ‘the green shift’ in practice, says property developer Arthur Buchardt of AB Invest.
Mjøstårnet is proof that tall buildings can be built using local resources, local suppliers and sustainable wooden materials. Voll Arkitekter has paved the way, showing that it is possible to build large, complex timber buildings and inspire others to do the same.
Currently in construction and open to the public in September 2021, when it is set to become the tallest wooden building in the world, the Kulturhuset Sara stands at 20 stories high and it’s located just below the Arctic Circle in northern Sweden, Skellefteå.
The Culture Center will be the home of Västerbotten Regional Theatre, Anna Nordlander Museum, Skellefteå Art Gallery, City Library as well as a hotel to accommodate the growing numbers of tourists visiting the city. In 2016, White Arkitekter won the competition to design the Culture Center, keeping in mind the concept of sharing space. The main entrance is a grandiose, light-filled atrium surrounded by a series of columns and is the backdrop for a grand staircase that connects to the hotel. The high rise, which houses the hotel, is constructed of pre-manufactured modules in cross-laminated timber (CLT), stacked between two elevator cores. Thanks to the placement and design of the cores, they can be entirely made from CLT.
— The design is a homage to the region’s rich timber tradition that we hope to take forward with the local timber industry. Together, we can create a beautiful civic centre for all; a contemporary expression that ages with grace, says Oskar Norelius, project architect.
Lighthouse Joensuu was a project supported by Finland’s Ministry of the Environment, where its goal was to minimise costs by using an efficient floor plan, optimised structures and innovative technology resulting in a 14-storey building, making it into Finland’s tallest wooden high-rise, with construction completed in 2019. The building contains 117 student apartments, nine per floor, whereas the ground floor hosts sauna facilities, a laundry room, technical facilities and storage spaces for household and outdoor equipment.
The Karelia University of Applied Sciences conducted measurements, acoustics research and evaluated the structure’s carbon footprint; studies to date reveal that only about one-fifth of the carbon footprint of Lighthouse Joensuu was generated during the construction period. Its wood product parts sequester carbon corresponding to the carbon dioxide emissions of about 700 passenger cars during the year.
Sustainability in construction requires us to use traditional materials, but also to innovate in material composition and clever design. Knock knock!
This article was originally published in issue two of Scandinavian MIND, in August 2021. See more stories from issue two below.