Two years ago, Tony Messina had big plans for the Chelsea School, the Silver Spring private school he runs for challenged students.

A $12 million dollar expansion to the school would include a new gymnasium, playing fields, a two-floor library and a 210-by-40-square-foot modern glass school building. Daniel Libeskind, a renowned architect who was designing the development at the former World Trade Center site in New York City, would design and partially fund the school, and it would host special-education researchers from around the world. It would all happen in Silver Spring, on a peaceful block off Pershing Drive, surrounded by single-family homes.

Messina still has big plans for Chelsea School. But after an economic downturn indefinitely postponed those expansion plans, he doesn't know when they will be realized.

And now, with a deal in place to sell the campus to a developer and relocate out of Montgomery County, it's unlikely those big plans will occur in Silver Spring.

"We didn't know what the market would do," Messina said Monday afternoon while looking over enlarged artist's renderings of the expansion plans in a room next to the school's main lobby. "The sale of the school gives us the capital to build this new school. We have to think more like a business."

Last week Chelsea School signed a contract with a subsidiary of EYA Associates, a real-estate developer in Bethesda, which will attempt to build up to 75 townhouses on the current Chelsea School site.

The deal, financial terms of which were undisclosed, is contingent on EYA gaining design approvals and a zoning-text amendment from Montgomery County within 90 days, Messina said. The land is zoned for single-family homes; Chelsea School is operating under a special exemption for schools, said Bob Youngentob, EYA's president.

"We don't believe that, economically, a single-family plan would generate the value that Chelsea needs relative to what another larger school would pay for the site," Youngentob said in a phone interview last week. "Townhouses make the most sense."

Chelsea School will not relocate until construction can begin on the townhome development, expected at the end of the 2011-2012 school year. At that point, the school will relocate into Washington, D.C., Prince George's County or both, to better serve its 88 students, only three of whom live in Montgomery County, Messina said. Ideally, Chelsea would move into an empty school building in either Prince George's or the District until market conditions allow the school to pursue grander plans, said Lou Steadwell, a member of Chelsea's Board of Governors.

"It's a chance to start fresh somewhere else," said Steadwell, a Washington, D.C., resident. "It's not the school of our dreams, but it's certainly an upgrade on the space we have."

When Chelsea School opened more than 30 years ago, most of the students were from Montgomery County and attended using private funds, Steadwell said. Most of the current students have left Prince George's or the District because their parents felt they were underserved by those public school systems, and they often required a court ruling to do so, Messina said. Those schools pay about $35,000 in tuition for every student that leaves for Chelsea School, and Messina said both Prince George's and the District contribute about equal amounts to Chelsea School's $3.5 million budget.

The number of students attending via public funds increased after the 2004 passing of the Individuals with Disabilities Education Act, which mandated that public schools provide special education to students with disabilities and allowed low-income families to pay for private special education with public funds, Messina said. Montgomery County students began decreasing as its national reputation grew and fewer parents sought alternative education, Messina said. And enrollment overall decreased as Montgomery County private schools that provide a more traditional education initiated special-needs programs.

"They like to put those bumper stickers on their cars," Messina said of parents who chose more prestigious schools to send their challenged teens. "We don't even have bumper stickers."

That's not to say Messina, a garrulous, youthful 62-year-old with a thick New York accent, a shiny bald head and a soul patch goatee, isn't proud of his school. He took over five years ago after parents angrily protested his predecessor's proposal to force all teachers to reapply for their jobs in an effort to ensure the quality of teaching at the school.

"Since Tony has been at the school, the relationship with the community has been very good," said Mark Gabriele, president of the nearby Seven Oaks and Evanswood Citizens Association.

On Monday, Messina walked through the school, cheerfully greeting students and explaining how he doesn't consider Chelsea a school at all.

"We are a family and a community," Messina said as he visited a science class. "This community can survive anywhere."

Despite pending changes in the school's physical location, its curriculum — or its "special sauce," as Messina calls it — will not change.

The curriculum will continue its focus on math and science, but hopefully with upgraded science and computer labs and increased efforts to tie verbal skills and arts education into existing curriculum, Messina said. The about one to eight staff-to-student ratio at Chelsea School will remain, Messina said, and he hopes the between 85 and 92 percent of graduates attending college will as well.

On Monday, Chelsea School junior and Largo resident Tori West attended a ceramics class with three other students.

"The teachers don't focus on individual students," West said of her experience in Prince George's County Public Schools.

In a science class, eight students sat in a tight rectangle of desks, some listening to their iPods, as they assembled models of DNA strands using beads. DeAntre Watkins, a Chelsea School sophomore from Washington, D.C., said the disciplinary issues in D.C. schools were so overwhelming that teachers could provide him with little individual instruction.

He said there's simply a different "vibe" at Chelsea and one he expects to follow the school—or "community"— wherever it goes.

"I like the small environment," Watkins said before pointing at his classmates seated a few feet away. "That's my brother, that's my sister."