Slate-clad addition to the American Swedish Institute evokes contemporary Scandinavian design.Minneapolis-based architecture, engineering, and planning firm HGA faced a tall order when the American Swedish Institute asked them to design an addition to the building known locally as "The Castle." The turreted Turnblad Mansion, constructed in Minneapolis' Phillips West neighborhood in 1908 and home of ASI since 1929, lacked the kinds of multi-purpose spaces required by ASI's cultural and educational programming—and was suffering wear and tear from a steady stream of visitors. "The project was about creating a front door that was more welcoming and inviting than the existing building, that can help protect the mansion and allow it to be used as a house museum," said project architect Andy Weyenberg. At the same time, "the mansion remained the focal point," he explained. "It will always be the identity of ASI. Everything we did, we wanted to respect the mansion and keep it as a centerpiece." HGA's intervention honors the primacy of the Turnblad Mansion while updating ASI's image with a contemporary facade inspired by Swedish building methods and materials. "The mansion doesn't relate well to the Swedish identity: it's a French Chateau," said Weyenberg. "ASI wanted to use the addition to reinforce their identity as a Swedish institution, but they were interested in doing that in a modern way, relating it more to modern Swedish design and architecture." Positioned across a courtyard, or gård (a traditional typology found in both rural and urban buildings), from the Turnblad Mansion, the new Nelson Cultural Center is clad primarily in slate shingles. "Slate is a common building material in Scandinavia, especially dark slate like that," explained Weyenberg, who says that it is primarily used as a roofing material, but that he has seen examples of slate cladding since working on ASI's expansion. The slate also matches that on the Turnblad Mansion's roof. "We're using material that's sympathetic to the mansion, but using it in a different way. It's clearly a new piece of architecture," said Weyenberg. He points out that although there's nothing particularly high-tech about how the cladding was installed—it is hung like a roof system—it promises environmental benefits in terms of durability and longevity. "The roof on the mansion has been in place 100 years," observed Weyenberg. The entrance to Nelson Cultural Center is lined with panes of blue textured glass, another nod to Swedish design. Sweden is known for its glassmaking, having produced art glass firms including Orrefors and Kosta Boda. ASI's collection also includes a number of significant glass pieces. "That was another way of tying the design back to Sweden, and creating a reference to the ASI's collection, while also creating a bold element at the entry," said Weyenberg. HGA worked with Louisville, Kentucky, glassmakers Architectural Glass Art (AGA) to combine layers of commercially available textured glass and resin to create the translucent panels. "There's not a strong reference in terms of its construction to Swedish glassmaking," said Weyenberg, "but there was a process in terms of working with AGA as a craftsman to come to a quality we all liked. We wanted something subtle in texture but with an organic quality that relates well to the slate." HGA took advantage of a consulting program sponsored by local energy provider Xcel Energy to locate windows and curtain walls to frame views of the mansion and maximize daylighting while minimizing energy loss. Other features contributing to Nelson Cultural Center's LEED Gold status include a vegetated roof over the gallery and event spaces. "Green roofs are a really common form of building in Sweden," said Weyenberg. "They've been building sod roofs on farm buildings forever." Nelson Cultural Center's contemporary design reflects ASI's commitment to celebrating the Swedish influence on the Twin Cities while connecting with Minneapolis' next generation of newcomers—including, in the Phillips West neighborhood, young Somali immigrants. "As part of this expansion, they were really trying to update their identity and keep themselves current," said Weyenberg. "Their core constituency is aging. They were looking for a way to keep themselves relevant, and to reach out to new audiences."