With its glass-driven emphasis on transparency, this Iowa headquarters is in perfect harmony with its sculpture garden neighbor.
PROJECT: Krause Gateway Center LOCATION: Des Moines SIZE: 163,307 square feet COMPLETION: November 2018 ARCHITECTS: Renzo Piano Building Workshop, OPN Architects STRUCTURAL ENGINEER: Robert Silman Associates MECHANICAL ENGINEER: Baker ELECTRICAL ENGINEER: Wolin SUSTAINABILITY & LIGHTING: Arup CONTRACTOR: Ryan Companies LANDSCAPE ARCHITECT: Confluence
The Krause Gateway Center, spearheaded by one of the leading architecture firms in the world, stands directly across the street from Des Moines’ premier public art attraction—and is itself a contemporary-leaning, high-design contribution to the built environment. The Renzo Piano Building Workshop-designed center—which houses employees from all the businesses under the Krause umbrella, including Kum & Go, Solar Transport, and the Des Moines Menace soccer team—cuts a striking figure across from the famed Pappajohn Sculpture Park thanks to its distinctive design elements—most notably its surrounding public green space, dramatic cantilevered roofs, and massive lobby windows.
But those eye-grabbing features are more than aesthetic triumphs; they’re also nifty sustainability assets. Glass is sometimes notoriously inefficient in terms of thermal control, but the large overhanging roofs directly address that concern. Their strategic positioning helps control temperatures in both hot and cold seasons. “The sun in summer is almost vertical, so it produces a lot of shadows,” notes Giorgio Bianchi, a partner at RPBW, who led the project design team. “We were able to reduce the impact of the direct sun inside.” In winter, however, the sun is lower and has far less impact. “Not zero, but much less,” Bianchi says.
The overhangs went a long way toward reducing the Solar Heat Gain Coefficient requirements for the center’s towering lobby glass panels. The team used neutral, low-emissivity coating for the glass, which has a high-performing U-factor, according to Anthony Kantzas, a facade consultant with Front Inc who collaborated on the project. Due to the lobby windows’ massive size—at 29 feet, they are said to be the second tallest insulated glass units in North America, trailing only the Apple Store in Brooklyn—occupants feel a connection to the surrounding natural landscape even from indoors.
RPBW, which collaborated on the project with OPN Architects, fashioned additional outdoor design elements. Employees can gather on a large green roof outfitted with native grass, and there’s the site itself: 75% is public gathering space, with bocce and chess areas, dotted with more than 100 trees. “The building becomes in some ways a civic building,” Bianchi says. There’s also an in-the-works public cafe and an art gallery visible from the exterior that opens to the public for special events. “It’s not the kind of headquarters where they make a castle, and in order to enter you need to open 25 doors,” Bianchi says.
360 Degree Views
The design team wanted to be sure stunning views were available throughout the space, not just on the green roof. “When you’re inside, because of the design, because of the overhangs, your eye [feels compelled to] look far away in the distance,” Bianchi says. Employees at the LEED Silver–targeting facility have 360-degree views of the Des Moines skyline, and the office layout itself was similarly designed to avoid sequestering. The team went with an open plan on each level to better encourage interaction and collaboration among staff.
RPBW made certain that the building’s profile and landscaping complemented its iconic neighbor to the south, the Pappajohn Sculpture Park. The onus on transparency and blurring of indoor and outdoor spaces—glass exteriors give way to large balconies that surround each floor—creates a direct visual connection between the two. Gary Hume’s “Back of Snowman (Black)” and “(White)” and Jaume Plensa’s much-loved, stainless steel “Nomade” are both visible from this perspective.
Along with the solar radiation-muffling overhangs and the thick glass with low-e coating, the choice of glass spacer was key in terms of thermal control. RPBW used ROLLTECH’s CHROMATECH, which promises up to 40% reduced heat loss at a pane’s edges. “Improvements on the edge spacer performance is still something as glazing consultants we are always pushing to improve, not only thermally but structurally,” Kantzas says. Spacers that can withstand high seal stress are ever more paramount as architects push for larger glass, he notes.
Among the notable features of the six-story center is a large-scale, multifunctional conference room that can hold several hundred people. As with the exterior, there’s an emphasis again on glass when it comes to indoor partitions. Other employee amenities at KGC include a fitness center and a game room. Tucked out of sight are two stories of underground parking—which allowed the design team to forgo surface lots and in turn maximize publicly accessible space.