January 20, 2016
By John Hutchings, AIA, LEED AP BD+C, Sports Principal-in-Charge, HKS Sports & Entertainment Group

HKS could have designed a simple roof for the new U. S. Bank Stadium in Minneapolis. Our clients, the Minnesota Sports Facilities Authority and the Minnesota Vikings, agreed that use of the standard retractable roof used in sports stadiums would be limited by the area’s cold climate.

Instead, the stadium’s innovative, fixed EFTE roof will make the most out of limited sunlight and warm weather. It serves as the lynchpin for the stadium’s site-specific design, high-level sustainability and unparalleled visual transparency. 

The stadium’s roof design is asymmetrical, with a single longitudinal beam/super truss. The steep pitch allows heavy snow loads to slide into designed snow containment basins and allows maximum sun exposure to the southern two-thirds of the roof with EFTE, resulting in a daylight-filled seating bowl.  

EFTE, a glass-like plastic, allows sunlight to heat the interior and warm air to collect in the unusually high roof, cutting energy costs. Although the product has been used in buildings for some time, exhaustive due diligence for the roof system and the individual components was needed. An HKS team of architects, mechanical engineers and consultants visited ETFE installations worldwide and the manufacturing plant in Germany to fully understand the product and its capabilities. Then, they applied the product science and their knowledge to develop the EFTE system design for Minneapolis. Developing the exact specifications for to create the desired transparency and determining the EFTE heat co-efficient and correct frit patterns demanded much time and team collaboration. 

Will the effort be worth it? When the stadium opens in summer 2016, Minneapolis fans will enjoy the game come rain or snow and still feel like they’re experiencing the closest thing to an outdoor stadium. And the stadium’s design has the potential for making it one of the most recognized buildings in American sports.