Craig Dykers says new structure will 'complement' existing building by Mario Botta

Since the San Francisco Museum of Modern Art opened its distinctive, Mario Botta-designed home in 1995, the size of its collection has more than doubled and the average number of annual visitors has tripled. The institution is now in the midst of raising money for a major expansion conceived by the award-winning Norwegian firm Snøhetta.

The museum launched a $480 million capital campaign last year to bolster the 225,000-square-foot project and the museum's endowment. So far, it has raised more than $250 million.

The expansion, slated to be completed in 2015, will double SFMOMA’s exhibition and educational space, with seven levels dedicated to galleries and two floors accommodating offices. The contemporary art collection of Gap founders Donald and Doris Fisher will occupy a large part of the facility. Snøhetta intends to release interior plans in November.

As for the exterior, preliminary designs released in May show a roughly carved, wedge-shaped building tucked behind Botta’s brick-clad edifice, famous for its striped, cylindrical turret. The new facility will rise 50 feet over the existing five-story building. An 18-foot-wide walkway will lead to the entrance of the new wing, with glazing at the ground level offering a view of the interior. To make way for the expansion, a fire house will be demolished and rebuilt on a nearby street.

Snøhetta principal Craig Dykers says his goal with the new structure is to complement, rather than eclipse, the Botta building. He adds that people often are surprised to hear about the expansion. “When you tell people you are adding to the Botta building, they say, ‘How can you add to it? There is no space,’” Dykers says. The museum is located in an area with massive blocks surrounded by six-lane roads and interlaced with small side streets. Dykers says the building site is “deeply hidden in the superblock,” and the new facility aims to pull people in and allow them “to experience the city in a completely new way.” SFMOMA hopes to begin construction in the first half of 2013.

Founded in 1989, Snøhetta has received numerous awards for projects such as the Oslo Opera House in Norway and the Bibliotheca Alexandrina in Egypt. Currently, the firm is working on the 9/11 Memorial Museum Pavilion at the World Trade Center site in New York. The building is scheduled to open next year.