Almost everybody is calling Michael Green’s T3 building “the largest mass timber building in the US”. It’s not, it’s probably not even close. At 220,000 square feet it is the largest wood building built in this century, and might be the largest built in the last 75 years, but there are hundreds of buildings across North America built like the T3 building, and I suspect many of them are bigger.* (see note at bottom for update)
Michael Green, in his press release, is a bit more accurate in his title: Minneapolis Claims The First Modern Mass Timber Office Building in the U.S.
T3, which stands for Timber Transit Technology, is marketed by Hines with this introduction:
We love old brick & timber warehouses. We love the feel of them, the originality, and the entrepreneurship that lives inside their bones. They are cool places to collaborate, create, and innovate. Unfortunately, these buildings lack good natural light, are drafty, noisy, and have outdated HVAC systems. So we asked ourselves, why can’t we solve these problems by selecting an authentic location, surrounded by heritage buildings, and construct a brand new, vintage building? All the charm of an old brick & timber building, with none of the downsides.
And that is what Michael Green has actually built, a brand new old building. It is built the same way as the Bullitt Center in Seattle, the Framework building in Portland and the MEC building in Vancouver: A post and beam structure made of Glue-laminated (Glulam) wood, a technology invented in 1906 and that's been upgraded since with better glues and CNC milling.
The floors are what used to be called mill decking, but is now known as nail-laminated timber, which sounds as sexy as cross-laminated timber. StructureCraft, the “design-assist builder”, explains why it was used:
The teams’ decision to go with NLT (nail-laminated timber) was formed on a number of factors including structural advantages, lower cost, and faster procurement times. For a one-way span, NLT and GLT (glue-laminated timber) panels are more structurally efficient than CLT panels, as they have all of the wood fibre going in the direction of the span.
In other words, when you have an old-fashioned post and beam building like this is, it actually makes more structural sense to have all the wood pointing in the same direction than it does to use the new cool stuff like CLT. It also is a known commodity, tested for over a century, and in every building code.
What is "Mass Timber" anyway?
In fact, and I am probably being a bit pedantic here, but it might even be a stretch to call the T3 building “Mass Timber”- it is hard to find a good definition of the term, but the earliest use I can find of it is in Michael Green’s own 2012 study Tall Wood:
A definition of Mass Timber which includes several existing large scale panel products in the current marketplace including Cross Laminated Timber (CLT), Laminated Strand Lumber (LSL) and Laminated Veneer Lumber (LVL).
All fancy new stuff. Nail Laminated Timber (NLT) isn’t on that list, probably because it wasn’t new and different, and it was often built up on site by carpenters out of a pile of 2x10s and a box of nails. It has evolved into a form of mass panel, as they were built offsite in a factory in Winnipeg, Canada and shipped complete, but it is not really a new technology. Another definition of Mass Timber Construction (MTC) from Weyerhaeuser, is simply "really big chunks of wood-based products." So I am definitely being pedantic. (See more on NLT)
UPDATE: Lucas Epp of StructureCraft, who made the NLT says " Mass Timber is being categorized as any solid wood panelized product. NLT is just the oldest example of a mass timber product."
Absolutely none of the above is meant to criticize or denigrate the building; in fact this is a feature, not a bug. It is actually one of the best things about the building, the way it has the feel of an old warehouse, but none of the problems of noise (it has a 1” thick sound mat and concrete floors) or air quality, with its modern HVAC systems.
There are a lot of benefits to building with wood; it is much lighter, reducing the size of foundations, it goes together faster, at a rate of 30,000 square feet per week, and because everything is exposed, the ceilings are higher without increasing the floor to floor height. And that is before we even get into the environmental benefits of building with wood, of sequestering carbon for the life of the building, for avoiding the carbon footprint of concrete, for using up piles of mountain pine beetle wood that otherwise would rot and release all of its CO2. It looks really nice, too; from the press release:
The building’s aesthetic success can also be attributed to the mass timber construction. Candice Nichol, MGA Associate and T3 Project Lead, says “the texture of the exposed NLT is quite beautiful. The small imperfections in the lumber and slight variation in color of the mountain pine beetle wood only add to the warmth and character of the new space.”
Michael Green concludes:
T3 is currently the largest completed mass timber building in the U.S. With changing building codes throughout North America, tall wood buildings will become more common. A pioneer in this building type, T3 has broken new ground and is perhaps a prototype for future commercial mass timber buildings.
There is much that is open for debate in that and the other claims. It's not the largest*, it's not the first, it's hardly tall, and it is not some fancy new Mass Timber Construction, it's good old post and beam with mill decking.
But hey, who cares. It is, no doubt, a great example of how the new can learn from the old to make better buildings and better cities: it is not too tall, it feels urban, built right up to the street. The rusty steel gives it a gritty industrial look right from the start. It is, as Michael Green describes it,
…a modern interpretation of the robust character of historic wood, brick, stone, and steel buildings with the additional benefits of state of the art amenities, environmental performance, and technical capability.
And we could use a lot more of that.
*Note: I searched to try and find a wood post and beam warehouse building in the US that was larger than T3 but couldn't find one specifically. However Toronto's beloved 401 Richmond Street is larger and its size is completely unremarkable in Canada, so I have no doubt that there are many in the States as well.
UPDATE: Lucas Epp of StructureCraft writes to tell me:
Is T3 the largest mass timber building in the US/North America? Definitely not. What we are saying is that it is the largest modern mass timber building in North America. [LA: except that is not what all the websites covering this building are saying, which is why I raised it] The Butler building in Minneapolis is one old project I always show – it is both larger and taller than T3, and is only a 5 minute walk away! It is 500,000 sq ft and 9 stories tall, built in the early 1900s.