The Council on Tall Buildings and Urban Habitat has dubbed the 85.4-meter Mjøstårnet, in Brumunddal, Norway, as the world's tallest timber building.
At the same time, the group amended the CTBUH height criteria – the official guidelines to measure and rank building height – to recognize timber as a structural material. The update was prompted by the recent uptick of tall timber buildings currently under construction or in planning around the world, and the interest of involved stakeholders and the general public in defining what truly constitutes a “timber” structural system, says CTBUH.
According to the revised criteria for timber structures, “both the main vertical/lateral structural elements and the floor spanning system must be constructed from timber." An "all-timber" structure may include the use of localized non-timber connections between timber elements.
A hybrid building of timber construction with a floor system of concrete planks, or concrete slab on top of timber beams, is still considered a timber structure, because the concrete elements are not acting as the primary structure.
Mjøstårnet is located in an area of Norway known for its forestry and wood processing industry. Moelven Limitre, the project’s structural engineer, supplied glue-laminated-timber columns, beams and diagonals, cross-laminated-timber elevator shafts, stairs and floor slabs. Moelven was also responsible for installing the mass timber structure