Sir David Chipperfield, with HOK as architect of record, is designing a modern, light-filled expansion of the Saint Louis Art Museum that organically connects with the original Cass Gilbert-designed 1904 Main Building. Known as the East Building, the 211,431-square-foot expansion takes advantage of the museum’s site in Forest Park. The structure’s polished concrete façade incorporates aggregates from the Missouri River. Inside, a Grand Stair transitions to the lower-level galleries, a concourse leading to a café, and a renovated shop and auditorium.

Outfitted with skylights, the white concrete coffered ceiling provides abundant natural light to the collection galleries and public spaces. Six-inch-wide quarter-sawn white oak flooring anchors the new building, which is also home to a 100-seat restaurant overlooking Art Hill. The project’s landscape architect, Michel Desvigne, is integrating outdoor sculptures into the exterior design—including the site-specific commission Stone Sea by Andy Goldsworthy. Additionally, the museum will seek LEED certification for the expansion.

The East Building will feature 21 galleries, increasing the museum’s total exhibit space by 30 percent. The galleries will showcase modern and contemporary art, with one gallery dedicated to antiquities as a way to integrate the new and existing buildings. The expansion also has prompted the renovation of 50 galleries in the main building, where curators are reinstalling 1,550 works—478 of which have not been on public view or at least 20 years.