Starting this summer, the Saint Louis Art Museum will have nearly a third more space to show off its encyclopedic collection, owing to a new addition.

At more than 200,000 square feet, the new East Building, designed by architect Sir David Chipperfield, adds more than 82,000 square feet of galleries and public space, an increase of about 30 percent. The expansion was supported by a $145-million capital campaign, to which, according to a press release, donors have already committed more than $160 million.

Chipperfield has to his credit international museum projects such as Britain's Turner Contemporary, in Margate (2011); and a rebuilding of Berlin's Neue Museum (1997-2009). Opening June 29-30, the new building affords Saint Louis a fully accessible new entrance along with visitor amenities like a new café and renovated auditorium. With dark polished concrete-and-stone panels and full-height windows, the addition offsets the original neoclassical building, designed by Cass Gilbert in Forest Park for the 1904 World's Fair.

"Celebrating the Forest Park site, harmonizing with the 1904 building, and creating a distinctive architectural work for our own time," said museum director Brent R. Benjamin in a press release. "The East Building will offer the people of St. Louis, and our visitors from around the world, a remarkable new view of the outstanding collections of this Museum and of the vital role that an art museum can play in public life."

What were special exhibition galleries in the 1904 structure will now accommodate the permanent collection, which has been reinstalled throughout more than 50 galleries, allowing a fresh view of works by artists ranging from ancient American art to Max Beckmann.

The inaugural offering in the East Building's special exhibition galleries will be a selection of postwar German art drawn from the museum's holdings, and will feature artists such as Georg Baselitz, Martin Kippenberger, Bernd and Hilla Becher, Andreas Gursky and Candida Höfer.

The first installation in the new building's permanent collection galleries will focus on postwar American art, with about a third of the works emerging from a decade in storage. The show will range from Abstract Expressionist masters and Andy Warhol to younger figures like Kerry James Marshall and Julie Mehretu.

Outdoor sculptures by Alexander Calder, Henry Moore and George Rickey will be featured on the grounds facing Forest Park, with landscape design by French landscape architect Michel Desvigne.