The San Francisco Museum of Modern Art (SFMOMA) has picked Snøhetta, a 100-member firm with offices in Oslo and New York City, to design a 160,000-square-foot expansion of its distinctive Mario Botta–designed building. In addition to providing new exhibition space, the $250 million expansion will consolidate administrative functions—freeing up room in the existing 225,000-square-foot building for new galleries and public spaces.

SFMOMA has grown dramatically since its move into the Botta building in 1995: yearly attendance has tripled to 700,000, and the collection has doubled, to 27,000 works. The expansion will replace two small buildings around the corner from the museum, and a bridge or tunnel between the buildings will bypass an alley that must remain open.

This will be Snøhetta’s first project on the West Coast, but only the latest in a string of high-profile cultural projects across the world, including the Bibliotheca Alexandrina, in Egypt, and the Oslo Opera House. The firm’s current projects include the entrance pavilion to the National September 11 Memorial Museum, now under construction at the World Trade Center site in New York; an arts center at Bowling Green State University, Ohio; and the King Abdulaziz Center for World Culture, in Dhahran, Saudi Arabia.

Craig Dykers, Snøhetta co-principal, said in a statement, “The new extension will unite the Botta design with its dynamic urban surroundings, becoming the tissue that merges building and community, supports the museum’s role as an educational and civic catalyst, and opens up the museum to the diverse audiences it serves.”

The announcement caps off a five-month selection process. Thirty-five firms were winnowed down to a shortlist of four: Snøhetta, Adjaye Associates, Diller Scofidio + Renfro, and Foster + Partners. The selection committee visited the finalists’ offices and toured selected projects—which proved to be the clincher for Snøhetta. SFMOMA director Neal Benezra said in a statement, “The selection committee was particularly thrilled by the stunning spaces, sophisticated use of materials, and quality of light in Snøhetta’s Norwegian National Opera and Ballet in Oslo, which we feel is one of the great buildings worldwide to be designed and built in the last decade.”

Snøhetta will partner with a local architectural firm to execute the expansion. Design concepts will be revealed next spring, with the expansion scheduled to open to the public in 2016.