The 85.4-metre-tall Mjøstårnet is now officially the world's tallest timber building, says the Council on Tall Buildings and Urban Habitat (CTBUH). The mixed-use structure in Brumunddal, Norway is also the third-tallest building in the country, and Norway's tallest with multiple functions.

Mjøstårnet, image by Moelven — Nina Rundsveen via CTBUH

The news comes as CTBUH amends its height criteria to include timber as a recognized structural material in response to a growing international trend in timber construction. The revised criteria lays out the definition for timber structures as follows: "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 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, as the concrete elements are not acting as the primary structure."

Mjøstårnet stands steps away from Mjøsa, Norway's largest lake, and is located in an area of the country renowned for its forestry and wood processing industries. Wood was selected as the primary construction material following advancements in mass timber technology, including the increased availability of glue-laminated timber and cross-laminated timber structural elements. CTBUH notes that wood is the world's only truly renewable building material, acting as a carbon sequester throughout its lifecycle.

Mjøstårnet, image by Moelven — Nina Rundsveen via CTBUH

The project's engineer, Moelven Limitre, supplied glulam columns, beams and diagonals, CLT elevator shafts, stairs and floor slabs. It also carried out the installation of the building's wooden structures.

CTBUH updated its height criteria following recommendations from the CTBUH Tall Timber Working Group. CTBUH will convene a dedicated "Mass Timber Symposium" at its 10th World Congress in Chicago, which is taking place from October 28 to November 2.

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