- 85.4 metre(s)
- Norway (Brumunddal)
The tallest load-bearing wooden building is Mjøstårnet, an 18-storey mixed-use tower in Brumunddal, Norway. It is 85.4 m (280 ft 2 in) tall and is the work of Voll Arkitekter and builders HENT and Moelven Limtre (both Norway). The height of the newly completed building was confirmed by the Council on Tall Buildings and Urban Habitat (CTBUH) on 14 March 2019.
The building's structural frame is made from a material called glue-laminated timber (GLT), and a similar material, cross-laminated timber (CLT), is used for the core walls of the stairways and lift shafts. The only significant elements of the structure to be made from concrete are the floor slabs for levels 12–18, which needed more mass to ensure the building's stability in strong winds.
The difference between GLT and CLT is the orientation of the sawn boards used. In a GLT beam, the grain direction of all the boards are aligned for maximum strength along a single axis. In CLT, every other layer is rotated 90 degrees, making the board equally strong in all directions. These laminated structural materials are stronger than traditional timbers, more consistent in the forces they can withstand and can be made to any size or shape. These qualities make them suitable for use in high-rise buildings.
Timber (when sourced from managed forests) is a much more environmentally friendly material than steel or concrete. The creation of glue-laminated timber beams requires much less embodied energy than steel or concrete of equivalent strength. Furthermore, timber is itself a carbon sink – the element, which trees extract from the air as part of photosynthesis, makes up between 40 and 50% of the dry weight of timber.