The new Ballou High will also feature a community center that will house a barber shop, a stage, a dance studio, an auto body shop and daycare.(Photo by Katherine Frey/The Washington Post)

Mayor Vincent C. Gray and D.C. Council member Marion Barry on Tuesday joined hundreds of hard-hatted construction workers in celebrating the topping-out of Southeast Washington’s new Ballou High, expected to open to students in January 2015.

Standing under the steel ribs of what will eventually be the roof of the new gymnasium, Gray (D) said the $142 million building — located in the District’s Ward 8 — represents his commitment to investing in neighborhoods across the city. “What we’re doing for one, we’re doing for all,” he said.

The new facility is the latest in a string of massive high school renovation projects that have replaced crumbling old buildings that were infamous for their disrepair. Many of those remade buildings, gorgeous as they are, remain half-empty with a majority of students working below grade level, giving rise to questions about how and whether the city can improve not just the schools’ physical infrastructure but the schools themselves.

“We all know it’s not what happens on the outside of a school. It’s what happens on the inside,” Barry (D-Ward 8) said. “From this point on, we’re going to look at what’s going on on the inside.”

Construction workers take a break to listen to speakers at Ballou’s topping out ceremony.(Photo by Katherine Frey/The Washington Post)

Students tend to arrive at Ballou years behind grade level; by 10th grade, about one in five are proficient in reading and math, according to city tests. Fewer than half of students graduate on time and more than 60 percent are considered chronically truant. Enrollment has dwindled to fewer than 700 as charter schools have attracted more families, but the new Ballou is designed to fit 1,400.

Charged with reinvigorating Ballou is new principal Yetunde Reeves, who comes to the District from a career as a teacher and principal in Oakland and East Palo Alto, Calif. She replaces Rahman Branch, who had led the school since 2008, when he was hired as principal by then-Chancellor Michelle Rhee.

The new building will welcome students back from winter break in January 2015 with 37 new classrooms as well as science labs, auto mechanic training and cosmetology training centers, a culinary arts kitchen, a greenhouse, performing and visual arts spaces, a swimming pool and more. The second phase of construction, including a new football stadium and auxiliary field, is slated to be done in August 2015.

“We’re all excited,” said Ballou librarian Melissa Jackson, flanked by a group of incoming ninth graders she’d brought to give a glimpse of where they will spend most of their high school careers.

Jackson arrived at Ballou several years ago and managed to turn its neglected library into sanctuary, a center of student life. But she said she’s looking forward to what the new building will bring: more space, more light, more technology and — she’s been promised — more books.

“It’s long overdue,” she said.

The front of the school will be mostly glass.(Photo by Katherine Frey/The Washington Post)