The Higher Ground multifamily structure in Minneapolis is a unique transitional housing center designed to combat homelessness. It provide a continuum of housing under one roof that offers an overnight shelter for the homeless as well as permanent housing for individuals ready to move beyond the shelter system. By combining the shelter and permanent housing, the structure design eases the transition from homelessness to long-term housing, allowing clients to literally ascend through the building as they regain their independence.
However, the project team faced many challenges in meeting all of the owner's goals, says Lisa Germann, associate architect with Cermak Rhoades Architects. The building had to fit a triangular, sloping site, and it had to be finished in just 12 months. That put pressure on the team to come up with a structure that would be quick and easy to erect while still meeting the owner's desire for an attractive building with light-filled rooms and open spaces.
Choosing a precast concrete design helped them overcome some of these obstacles.
"The use of precast concrete for the new facility's structure, envelope, and finishes contributed in many ways to the success of the new building and the ability to serve its residents," Germann says. "It allowed us to introduce a variety of colors and textures to the building exterior, with a timeless modern design at a cost that worked within the nonprofit developers' tight budget."
The combined precast concrete structure and envelope also allowed the team to cut six weeks from the construction schedule, which was critical in the tight time frame, Germann says. Panel delivery and structure erection was launched just 11 weeks after fabrication began, and capping of the seven-story tower and one-story link occurred 11 weeks later.
Durability and maintenance were also key factors in choosing a precast concrete design. "Not only was the nonprofit developer concerned about how long the building materials would last but also how the material selections and envelope would affect their operating cost," she says, but the use of precast concrete allayed their concerns.
The precast concrete sandwich walls provide a tight, well-insulated skin-exceeding ASHRAE 90.1-2004 requirements by 23%-to minimize air infiltration and reduce energy use. Precast concrete stairs were left exposed, and concrete topping on the precast floor structure was polished and used as the finished floor in many areas, contributing to the building's modern architectural aesthetic as well as enhancing durability and facilitating maintenance. The precast concrete structure and envelope also met the higher fire-resistance requirements for a building of this height, size, and use within a tight budget.
The new building's facade features thin brick and warmly colored precast concrete panels to create a welcoming yet contemporary residential feel within the nearly all-precast concrete envelope. The designers added depth in the facade with a series of long horizontal recesses highlighted by colored metal panels.
"This amount of relief (approximately 2 ft [600 mm] deep × 23 ft [7 m] long) was facilitated by the use of a precast structure and envelope," Germann says. "Other structural and envelope systems could have accomplished these spans, but the use of precast for both the structure and envelope made for a more seamless, energy-efficient and cost-effective solution."
The precast concrete panels also allowed for large windows to be included in key areas of the building to draw light in and create a connection between the residents and the rest of the community.
"When precast was first suggested for this building, we all had preconceptions about how this selection may affect the project," Germann says. "But together, we pushed precast beyond conventional practices, evolving into a highly expressive, durable, and efficient building."