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Transitional Steel

Mgmcgraths T3 2

Weathering metal changes color like masonry

The architects for the T3 office building in Minneapolis say locale was a driving influence for the design and materials.The architects for the T3 office building in Minneapolis say locale was a driving influence for the design and materials. Its pre-weathered steel exterior is similar to neighboring brick warehouse buildings in color and ability to change over time. This dynamic quality also reflects the ongoing development of the surrounding area.


Transitional Design

The T3 office building sits at the edge of the downtown core and beginning of the Minneapolis Warehouse Historic District. The transition between the two is noticeable. Some parking lots on the border of the downtown area are followed by numerous masonry warehouse and factory buildings from the end of the 19th century and beginning of the 20th century. The old buildings are undergoing a transition of their own. Many have been repurposed into residential, commercial and retail spaces.

Candice Nichol, AIBC, NCARB, associate at Michael Green Architecture in Vancouver, British Columbia, Canada, the design architect for the project, says, "There's the really rich, historic district that's becoming very active and revitalized. There's a lot of foot traffic, and a lot of owner-operated shops and restaurants. It's a really cool, funky, developing area that's drawing a lot of attention."

Like the brick on the warehouse buildings, the steel panels develop distinct color variations and textures with time, pollution and wear and tear. "[The brick] creates its own character," Nichol says. "Right now [the weathering steel is] that kind of richer, orangey, rusty color, and it'll weather and get darker as it continues to oxidize. And that's largely what drove the selection of the Corten, because from day one it will look different every single day."


Modern Interpretation

Photo: Joe Brennan, Phalanx StudiosIn addition to giving the building colors that complement existing architecture, the architects used similar scale and proportions. The 220,000-square-foot building is seven stories; many of the neighboring warehouse buildings are six to eight stories.

"The form of the building, material for the skin and proportions of the façade-they all came to be through studies of the neighborhood and finding ways that we could, in a new and modern way, reflect the historic environment," Nichol says. "We found that the weathering steel skin achieved those things because it's a modern material, but it has a life of its own and will weather similar to the brick and stone of the surrounding neighborhood."


Exposed Materials

Photo: Joe Brennan, Phalanx StudiosThe steel matched other materials for the project in its ability to be left exposed. The judging panel praised the design's "strident" use of metal and other materials as-is.

The building's structural system is mass timber with a concrete core, both exposed in the interior. Steve Cavanaugh, AIA, LEED AP, principal, design leader at Minneapolis-based DLR Group, the architect of record, says, "We expressed the textural quality of the forms, so you see the wood grain, the boards that formed the concrete. When it came time to skin the building, we wanted a material that was expressive of its inherent qualities, and that's one of the things that led us to the Corten."

"[The steel panels are] not painted, essentially that's the key," he says. "It's got nothing covering it. The idea that it has a very honest and naturalistic quality is what we really like."

The exterior is clad with three metals, two types of steel and aluminum. Maplewood, Minn.-based MG McGrath Inc. installed 27,466 square feet of Phoenix-based Rollfab Metal Products' A606 steel, corrugated wall panels with its Fuego pre-weathered finish and 2,825 square feet of the same panels with perforations. They are 7/8-inch deep and have a sinusoidal corrugation. Rollfab Metal Products supplied all the steel for the project.

Also, MG McGrath fabricated and installed 15,069 square feet of 20-gauge A606 steel reveal wall panels with Fuego pre-weathered finish, and 1,000 square feet of Allentown, Pa.-based ATAS International Inc.'s 0.08-inch aluminum with a black, two-coat Kynar finish for reveal panels, recessed jambs and sills for all the windows, flashings and other details.

In the interior, MG McGrath fabricated and installed 4,000 square feet of 16-gauge A606 steel wall panels with its Rainier blackened finish for tables, column covers, cabinets and a feature wall with perforation in the T3 brand. Additionally, MG McGrath fabricated and installed 1,000 square feet of 16-gauge A606 steel wall panels with Fuego pre-weathered finish and 500 square feet of A606 corrugated steel railing with two finishes.

T3 Office Building, Minneapolis
Completed: November 2016
Total square footage: 220,000 square feet
Owner: Hines Interests Limited Partnership, Houston
Architect of record: DLR Group, Minneapolis,
Design architect: Michael Green Architecture, Vancouver, British Columbia, Canada,
General contractor: Kraus Anderson Construction Co. Inc., Minneapolis,
Fabricator/installer: MG McGrath Inc., Maplewood, Minn.,
Aluminum: ATAS International Inc., Allentown, Pa.,
Metal wall panels/steel: Rollfab Metal Products, Phoenix,


Photos: Joe Brennan, Phalanx Studios