Work is to begin Monday to transform Camden's historic Wilson Building on North Broadway into an outpost for LEAP Academy University Charter's high school, an expansion that will include a gym, a cafe with WiFi, and a college resource center open to all the city's students.

The expansion of LEAP's S.T.E.M. High School, which specializes in science, technology, engineering, and mathematics, will help the city's largest charter school network continue to grow, said LEAP founder Gloria Bonilla-Santiago.

"It will feel a little like a college campus," she said. "Our students are very much in need of that ambience, that chance to socialize and work together on ideas."

The renovation of the 1920s-era, 12-story building known as Camden's first skyscraper is expected to be complete by March or April, she said. LEAP bought the building, adjacent to the school's Cooper Street campus, for $2 million in February.

Situated near three college campuses, Cooper University Hospital, and two public transportation stations, the 73,000-square-foot property has long been seen as ripe for development. It once housed Coca-Cola and the Miller Brewing Co., but has sat vacant since the 1990s, its only revenue coming from an ATM on the street and cell towers on the roof.

The building was partly renovated in 2009 by an out-of-state development firm that intended to fill the space with offices and retail space, but those owners eventually returned it to the bank.

Meanwhile, as Camden's state-run schools have continued to struggle with dismal test scores, the number of charter and hybrid Renaissance schools in the city has grown. About one in four of the district's 15,000 students attend charters.

Founded in 1997, LEAP now operates lower, upper, and high schools that serve 1,500 children, Bonilla-Santiago said, and has a wait list with enough names to fill two more schools. The high school has had a 100 percent graduation rate for a decade, and most of its students are accepted to college.

Opponents have said charter and Renaissance schools are draining much-needed millions from the district's budget, and others have raised concerns that the trend will lead to a complete corporate takeover.

Bonilla-Santiago said all of Camden would benefit from LEAP's successes, which she attributed to its focus on smaller class sizes and longer school days, as well as smarter spending of the $15,000 per pupil the schools receive from the state.

"This is part of a long-term strategy for transforming public schools in the city," she said.