November 16, 2017
by Alex Bozikovic
I can smell the fragrance of forest. In this case it’s emanating from some planks of softwood attached to a lobby ceiling at T3, an office building in downtown Minneapolis. A few steps further in, a stair made of edge-laminated veneer lumber rises into the corner, past a photographic mural of a coniferous forest.
Its developer—Houston, Texas-based Hines—has named it T3, for “timber, transit and technology,” and all of this woodiness, real and symbolic, indicates the building’s raison d’être. Its main distinction is the mass timber framework that supports the bulk of its 220,000 square feet. For its designer, Michael Green Architecture (MGA) of Vancouver together with architect-of-record DLR Group of Minneapolis, T3 represents the future of engineered wood. A post on Dezeen claimed that Michael Green “has pushed the limits of the material with his latest project.”
The building is actually hybrid; the exterior facades of the building are clad in weathering steel, and the first floor is conventional concrete, as is the core of the seven-storey building. There is no structural timber to see until you enter the tenant floors above, and even the particular technologies employed there—nail laminated timber (NLT) and glue-laminated timber—are not new. So the building doesn’t live up to that breathless Dezeen billing, which, like much of the current discourse on wood, overhypes the material’s current possibilities.
T3. Photo by Ema Peter
Yet T3 is an important building—not because it is technically exceptional, but because it suggests a new normal in architecture. Hines is no mom-and-pop developer but an incredibly large, multinational real-estate and investment company operating in 201 cities and 21 countries. This is the building that marks the acceptance of 21st-century engineered “mass timber” by the North American development industry, an advance that could see wood—a lightweight, strong, sustainable alternative—begin to take the place of concrete and steel as a structural system in midrise and high-rise buildings.
Photo by Ema Peter
T3 provides a case study in why North American developers will choose to join that shift: because wood feels good. For Hines, the impetus was a market demand for workplaces with the aesthetic appeal of century-old lofts in warehouse districts such as the North Loop in Minneapolis, where T3 is located. “We bought a brick and timber building just across the street from the site, and we got a sense of the demand—tech firms and even Fortune 500s were starting to look at these things,” explains Robert Pfefferle, director of Hines’s Minneapolis offices. “We asked: Could we reproduce it”—that loft experience—“in an authentic way?”
To do so, Hines turned to Michael Green and the engineering and fabrication company Structurecraft. Green is the most visible proponent of mass timber in North American architecture. “My whole career right now is about the idea that we need to move to more wood buildings in urban environments, and carbon sequestration,” Green says. His office produced a report in 2012, The Case for Tall Wood Buildings, which studied the potential for wood skyscrapers up to 30 storeys; Green’s 2015 TED Talk on the subject has been viewed 1.2 million times to date. In that talk, he cites the statistic that one cubic metre of wood contains—or sequesters—one tonne of carbon dioxide. “For us,” Green says, “the sustainability argument is the argument.”
A wood motif dominates the ground floor. Photo by Ema Peter
MGA is working on mass timber buildings in France, where the national government has aggressive carbon-reduction targets enforced by regulation. But it’s not an easy task in the United States, says Green, “so you have to go out with a hard pitch on quality,” says Green. The haptic, visual and olfactory qualities of wood come into play. Wood feels good. It looks good. It smells good. Touring empty floors of the building, I was able to experience the building in its pristine form, as the architects have chosen to represent it online, and to see the wood up close.
Exposed on the ceiling was the bottom surface of the nail-laminated timber. This, also known as mill decking, is a 19th-century construction technique: a stack of lumber, in this case 2×10 spruce-pine-fir, is fastened together with nails running through the flat side of the planks. Together the wood acquires enough strength to carry heavy loads; at T3 these slabs are topped with sound insulation and then a polished concrete pad. The structure that holds up those floors is also wood, glue-laminated spruce that was sourced in Austria and fabricated in North America. Deep beams run outward from the core to the perimeter of the floorplate, which is roughly rectangular; these beams rest on notched columns, the connections reinforced with steel plates that have hidden connections. The deep joists appear exceptionally bulky. This was a necessary compromise in order to achieve bays of 20 by 25 feet; Hines required those long spans in order to achieve a degree of flexibility in floor plans and in situating the demising walls between tenant spaces.
Upon its completion last year, T3 became the largest mass-timber building in the United States, although building codes and economies of scale will have to improve in order for tall wood buildings to become commonplace. Photo by Ema Peter
The wood is very attractive. The glulam spruce is nearly knot-free, smoothly finished, and is adhered together so that the seams are nearly invisible; the surface of the NLT is knotty and slightly inconsistent in tone, but quite handsome.
On the other hand, the realities of a spec building interfere with the precise detailing that architects (and architecture journalists) love. At the exterior edges of the building, the wood structure crashes into walls fireproofed and coated in drywall. Demising walls between units are, likewise, steel frame and drywall, which has been fitted under the wood beams after the fact.
In a reflection and hommage to its structural framework, wood interiors furnishings and furniture are visible throughout the building’s common spaces. Photo by Ema Peter.
Across the floors, HVAC ducts and electrical conduits are fastened to the surface of the ceiling. In the most radical version of contemporary mass timber construction, those floors would be made of cross-laminated timber (CLT), which can be custom-fabricated and cut to precise dimensions, even incorporating mechanical conduits. In this case, Green explains, the use of NLT “was driven purely by cost.” But if there are imperfections, it may be that no one outside of the architectural profession cares. Precision, in contemporary office space, is not the goal.
Pfefferle explains that many employers, “even in Class A buildings, are pulling out the ceiling tiles, because they’re more interested in the idea of collaboration space than in how that ceiling looks.” Employers associate an unfinished quality with informality, creativity and comfort; and “their real estate is not just a requirement, but a recruitment tool and retention tool,” the developer explains.
Green adds: “What people want is not the glass shiny box with the anonymous quality that we’ve seen over the last generation of office buildings. It should be filled with the texture of wood. The fact that there are imperfections in the material, the fact that it’s a little rougher, it just bringsback some of the character of the warehouse districts built a century ago.”
Photo by Ema Peter.
During my September visit of T3, I could not access any tenant-occupied space, including the suite then under construction for the notoriously private Amazon. However, it’s likely that the results will be messy. Just as in a retrofitted loft, tenants will occupy the floors with their own requirements for electrical, lighting and ventilation; partitions will be inserted for private offices. Green has seen drawings by Amazon’s interior architects. It’s a safe bet that whatever Amazon does, it’s not what Green would do.
An obvious tension exists between the reality and the commissioned photographs that reveal the outer facade and something of the inner structure. This invites a look back to the Modernist avant-garde and its rhetorical obsession with structure. In 1922, Mies van der Rohe introduced his all-glass skyscraper design in the journal Frühlicht. He wrote: “Only skyscrapers under construction reveal the bold constructive thoughts, and then the impression of the high-reaching steel skeletons is overpowering. With the raising of the walls… the constructive thought, the necessary basis for artistic form-giving, is annihilated and frequently smothered by a meaningless and trivial jumble of forms.” Mies overcame that problem, later in his career, with a sleight-of-hand: From the 1940s onward he took the I-beam, that building block of the tall building, and applied it to the outside of his towers in a decorative role. The Seagram Building, completed in 1958, is faced with bronze-hued I-beams that have no structural purpose.
T3 in the urban context. Photo by Ema Peter.
Something very similar is now happening in wood construction and its representations. The blogs are filled with drawings of the most beautiful and innovative techniques, including CLT and dowel-laminated timber (which relies on the expansion of wood components to fasten members together), but these are not yet commercially viable across North America.
T3 Minneapolis “was a developer building,” Green points out. “Technically, it could be all wood—my preference is always a core in wood—but it needed to be cost-competitive against any other system. The challenge here was: could it be competitive with a spec office building with a lay-in ceiling on steel construction?”
That will be the calculation that could ultimately change the world. And while both the developer and architects refuse to disclose the construction budget, they claim to have reached that goal–and are collaborating on a number of other T3 buildings in U.S. markets. MGA, meanwhile, has a series of “very large” office buildings under development, Green says. T3 is not a masterpiece, but it is real. “It will be the seed,” Green argues, “of something that will grow a lot farther.”
Alex Bozikovic is architecture critic for The Globe and Mail and co-author of Toronto Architecture: A City Guide.