The 7-storey office block with 20 000m2 of floorspace is designed to sit comfortably in Minneapolis’ historic industrial environment, The North Loop. Low-key, but internally a showcase for wood, T3 currently is the largest modern mass timber building in the USA.
At the turn of the last century the railways had their workshops and engine sheds here, and there were also factories and large warehouses, built from wood, iron and brick. Today, The North Loop is known as the city’s hippest neighbourhood boasting expensive apartments, popular restaurants, creative companies and trendy shops. The brief was to create a wooden building that was modern in every respect, referenced the area’s history and merged seamlessly into its robust surroundings, a building that would attract companies looking for a place that embodied local creativity.
Use of Timber
In contrast to many other modern wooden buildings which make wide use of cross-laminated timber (CLT), the material choice for T3 has been nail laminated timber (NLT) for the 20 cm thick floor joists. This has entailed dusting off a low-tech, well-proven and good value alternative to modern engineered woods. NLT has been used for over a century and basically comprises planed 2 x 8 inch planks nailed together on edge to form a rough and ready mass timber product. The majority of the wood used for T3 is taken from pines hit by the mountain pine beetle.
Using glulam posts and beams, the load-bearing structure for the whole of T3 was able to be erected in less than 10 weeks – nine days per storey – which is significantly shorter than for a conventional building in steel or concrete.
Having a ground floor with a concrete slab cast over an acoustic mat and taped OSB panels has made the client more comfortable with the building’s wooden structural frame. A façade of weathering steel not only keeps the elements at bay but enables the exterior of T3 to sit comfortably in its historic industrial setting.
Warmth is added to the concrete structure on the ground floor with the help of wood in the wallpaper, the stairs and the handrails.