Norway’s 18-storey Mjøstornet will be the tallest wooden house in the world.
When completed in March 2019, Mjøsa Tower in the Norwegian town of Brumunddal will be the world’s tallest wooden building. The construction, which started in early April this year, will stand over 80 metres tall, and its 18 storeys will house offices, a hotel and apartments.
This high-rise is being built using glulam, CLT, and LVL. To ensure the required load-bearing capacity, cross-bonded veneer panels called Kerto-Q LVL from Metsä Wood will be used for the flooring between the storeys.
Wood is an environmentally friendly building material. As a raw material, it is renewable and abundantly available in the Nordic countries. The material absorbs more carbon dioxide as the tree grows than the quantities emitted in the manufacture of this construction material. The wood’s light weight means less transportation and lighter foundations of the kind required for concrete buildings.
Using wood as the main construction material, even in high-rises, is key to shortening the construction time and, consequentially, cost. Modern technology enables us to prefabricate all components in a factory with a very high degree of precision. Compared to cast-in-situ concrete, wood makes it possible for construction time to be slashed by half. In addition, it’s relatively easy to make adjustments or corrections on-site.
3D view of Mjostornet
“The floor structures, which consist of massive beams with Kerto panels on top, are assembled in our factory, just 15 km from the construction site. Obviously, that’s a huge advantage if you have something that needs to be adjusted at the factory. The work is progressing at the rate of one storey a week, which has shortened our construction time by approximately 35 to 40 per cent compared to using cast-in-site concrete. And since the wooden components are so lightweight, we don’t need the machinery to be as heavy,” Rune Abrahamsen, Managing Director of Moelven Limtre AS, said.
Despite the commonly-held belief that wood burns easily, it doesn’t.
“Fire safety rules state that buildings must be able to withstand a full fire for at least two hours without collapsing. When you have a building made of steel and concrete, the steel melts and the building collapses,” said Erik Tveit, Project Manager at HENT AS, the general contractor for the site.
Nevertheless, concrete will be used between the floors of the Tower’s top seven storeys. As the swaying that increases the higher you get in a building, the weight of the concrete in the upper storeys reduces the swaying and is not as obvious.
All images: Metsa Wood