The Corcoran building on 17th St. NW is now owned by George Washington University. (Linda Davidson/THE WASHINGTON POST)

Much of the graceful interiors of the historic Corcoran Gallery of Art will remain intact, despite the wishes of new owner George Washington University, thanks to a successful preservation campaign by a District nonprofit organization.

The Historic Preservation Review Board on Thursday extended historic landmark status to most of the landmark’s interior.

The university had asked that historic designation be limited to the building’s “ceremonial spaces,” including its atrium, rotunda and grand staircase.

“It’s a real victory for the Corcoran as an institution,” said Bobbie Faul-Zeitler, a former Corcoran staffer who testified in favor of the nomination at the March 26 hearing. “The Historic Preservation Board certainly understood the Corcoran has played an important role in the cultural life of the city.”

George Washington University took ownership of the 1897 Beaux-Arts structure, located near the White House on 17th Street NW, in August as part of the deal that divided the failing Corcoran. The National Gallery of Art took custody of the museum’s 17,000-piece art collection, while the university took over the school.

The 17th Street building, designed by Ernest Flagg with a later wing by Charles Platt, was first designated a historic landmark in 1964. It joined the National Historic Registry in 1992.

At last month’s hearing, university representatives sought to limit the designation, saying they need flexibility to use the space for educational purposes. But in its nomination, the nonprofit DC Preservation League requested that historic status extend to most of the building, including the auditorium and basement studio space.

While the approved designation includes a majority of the building’s galleries, it does not include the basement, auditorium and four galleries on the first floor.

A university spokeswoman expressed disappointment in the decision.

“We have been supportive of designating major interior ­spaces as historic, but we are disappointed that the Board decided to designate so much of the building’s interior as historic,” Candace Smith said in an e-mail. “We will continue to work with the Historic Preservation office as we plan our phased renovation of the building.”

The DC Preservation League nominated the interior spaces for historic status in 2012,
almost two years before the three-way deal between GWU, the National Gallery and the Corcoran was approved by the court. During testimony last month, university officials argued that the wider designation would be a financial burden.

The university announced Tuesday that it had reached a deal to sell the other Corcoran building it received as part of the landmark agreement. The Fillmore, a historic school building in Georgetown, will be sold to the S&R Foundation for use as an arts incubator.