With a planned opening for later this month, the seven-story, 220,000-square-foot T3 (Timber, Technology, Transit) office building in Minneapolis will be the largest contemporary wood building in the U.S., according to Architect Magazine. Most of the wood is from Pacific Northwest trees killed by the mountain pine beetle. Minnesota's building code classifies the wood as Type IV Heavy Timber.
The building features a grid-based framing system using a combination of spruce-pine-fir nail-laminated timber (NLT) panels, spruce glulam and concrete. Crews framed 180,000 square feet in a little more than nine weeks, translating to 30,000-square-foot of floor space installed each week. The lightness of the almost all-wood building has reduced the seismic load significantly.
- Its architect, Michael Green Architecture, left much of the interior wood exposed, which saved money on finishes, while using indirect lighting for illumination after dark to highlight the use of wood as a structural material. The building will also feature a ground-floor space for public use.
Wood buildings are popping up all over the place, and plans for future structures run the gamut from doable to conceptual. Currently, the tallest wood building in the world is the $39-million, 18-story Brock Commons residence hall at the University of British Columbia, in Vancouver, Canada, which is scheduled to open in September 2017. The tower will be able to accommodate 400 students.
Meanwhile, Perkins+Will has proposed an 80-story all-wood tower along the Chicago River. River Beech Tower would feature a center atrium and an aluminum veneer over a lattice of wood beams. If built, it would be the tallest wood building in the world.
In the relatively new space of all-wood buildings, there are many candidates for the title of tallest wood tower waiting in the wings, but building codes and fire safety are an ongoing concern. While not part of the cross-laminated timber (CLT) or NLT discussion, but still dealing with wood, Sandy Springs, GA, recently changed its building codes to eliminate wood as an option for multifamily structures more than three stories high and larger than 100,000 square feet.
While city officials said the motive was safety, Justin Mihalik, president of the American Institute of Architects New Jersey chapter, told Construction Dive last month that the necessary fire ratings can be attained using most any material. "If it's tested and meets requirements," he said, "wood is safe."