Twenty years ago, an abandoned public school building in Montgomery County became a social services hub for a working-class neighborhood that was rapidly transforming into a major destination for newly arriving immigrants.

Since then, converted classrooms have become subsidized apartments for single mothers and their children. An old gymnasium serves as a community center that neighbors book for events such as first aid training and foreclosure prevention counseling.

A nonprofit organization known as Crossway Community, which oversees the center, also offers parenting classes, jobs counseling, and Montessori-based child care and preschool classes, which draw long waiting lists every year.

On Thursday, the Montgomery County Board of Education will decide whether to restore part of the old building to its original purpose by approving the county’s first public charter school. The application may offer lessons for how future charter proposals could succeed in a suburban system that has been skeptical of the independently operated public schools.

Crossway’s proposal to expand its preschool program through the third grade in partnership with the school system was endorsed by Superintendent Jerry D. Weast before he retired last month. It also was backed by a panel of community leaders and school administrators, which commended its “strong academic design.”

Kai Stanton, left, and Elijah Mubanga catch raindrops at Crossway center, which could become Montgomery’s first charter school. (Dayna Smith/FOR THE WASHINGTON POST)

School board member Patricia O’Neill (Bethesda-Chevy Chase) said the proposal shows “a demonstrated academic program” by an organization with “ a demonstrated track record of working with an underserved population.” She plans to support it.

On the eve of the vote, several board members said they were still weighing their decisions.

“I’m very aware that we have a reputation as being anti-charter,” said board member Laura Berthiaume (Rockville). “But we have a responsibility to make sure that taxpayer money is spent in the best interest of kids.”

The school would open in 2012 and eventually serve up to 188 students from preschool through third grade. It plans to hire state-certified teachers and incorporate state learning standards into the curriculum. In exchange, the county would give the school about $14,000 annually per student. It would become the first public Montessori program in Montgomery.

Developed in Italy a century ago, the Montessori method is distinguished by mixed-age classrooms and student-directed learning. It also emphasizes life skills and social skills.

On Tuesday morning at Crossway’s summer program, children working alone or with a friend in a classroom for 3- to 6-year-olds would unroll a small, white area rug and settle onto the floor with an activity or game they selected.

One boy was sounding out the names of birds in a stack of flashcards; another leafed through sheet music and quietly tapped a drum. Two girls were assembling a puzzle map of Europe, and three children were assembling plastic beads and counting along. The teacher was there to answer questions or make suggestions.

The children wore blue shirts, khaki pants and slippers on their feet instead of shoes, a practice that helps keep the room clean and calm. Outside the classroom, lunch tables were set up with cloth place mats and napkins and real plates and silverware.

Montessori values are reflected in the facility, which is almost hospital-like in its spareness and cleanliness, down to a “Ritz-Carlton approach” to cleaning the floors, which requires two buckets of soapy water and multiple towels so no dirty towel is used again.

The “prepared environment” limits distractions, said Kathleen Guinan, Crossway’s executive director. “This is a museum for learning.”

Guinan said the Montessori program has helped give children from disadvantaged families a strong start.

A community activist who speaks passionately about “leveraging social capital,” Guinan honed Crossway’s application over the past year, working with school system administrators to learn the rules of public education. The resulting application is a four-inch-thick binder with hundreds of pages detailing the school’s insurance, architectural design, proposed food service and accounting policies.

She said she sought to expand the program as a charter school in part because a partnership with a “world-class school system” would bring the highest academic standards. She also said her organization’s mission is aligned with the school system’s efforts to help children in poverty.

One possible complication: Under federal and state law, charter schools must be open to everyone in the county regardless of family income. And if applications exceed seats, students must be chosen by lottery.

Last year, the school board voted down an earlier application from Crossway in part because it had asked for a legal waiver that would allow the school to serve more students from poor families.

This year, the group withdrew that request and said it would comply with all relevant laws. State and county officials said it would be possible for the school to target its recruiting in the poorest areas.