Citing both its success and its overcrowded classrooms, Mayor Michael R. Bloomberg and school officials broke ground Monday on a new school building for Beacon High School on the far west side of Manhattan.

“It is one of those screened admissions schools with nearly 99 percent of the students graduating within four years, and 82 percent go on to college,” Mr. Bloomberg said. “It is also so popular that it’s very overcrowded.”

Beacon is one of the city’s top screened high schools, competing with the specialized high schools for some of the city’s best students. Its current campus on West 61st Street was designed for 837 students, but currently serves almost 1,300 students. The new school will be able to accommodate about 1,500 students.

The announcement culminates what Ruth Lacey, the principal, said was an intensive lobbying effort. “Six years ago I started my nagging,” she said. “You can’t leave anybody out.”

The new seven-story school at 521 West 43rd Street was once a New York Public Library warehouse. It was purchased for $45 million by the School Construction Authority last August. A massive renovation will include wireless Internet access, technology labs, a dark room, music rooms, a full-size gymnasium and an auditorium. The city predicts the new Beacon will be ready for the 2015 school year.

Ms. Lacey said that parents hadn’t yet digested the news but that she expected a positive response.

“If we tell parents, ‘We’re having a full gym,’ those seem to be the magic words,” she said.

Schools Chancellor Dennis M. Walcott said Beacon would be built to better provide for special education students as the city moves toward greater inclusion. It should also help Beacon meet the city’s directive that screened high schools should enroll as many students with learning disabilities as neighboring schools do.

“It’s a step-by-by process,” he said. “Every new building that we build, we have special education students who are now officially part of the building.”

Ms. Lacey, the founding principal of Beacon, said she was committed to continuing the school’s emphasis on small groups of students working together, and a personalized teaching approach. She did, however, express one concern with the new facilities.

“The current building is horizontal,” she said, which made it easier for her to monitor students and supervise staff. The new school will be a vertical community. “How am I supposed to keep track of anything here?”