Nearly 80 speakers packed the Arlington County Board chamber on Saturday, most to express their support for an unconventional mixed-use development project being proposed by First Baptist Church of Clarendon.

Board members listened for the better part of four hours and ultimately voted to approve plans to tear down the 54-year-old sanctuary at 1210 N. Highland St. and build in its place a smaller church and 116 residential units -- 70 of them designated for affordable housing. Also included in the plan is an agreement to preserve an education building on church property that houses the Child Development Center, Arlington's largest private day-care center.

"It's a wonderful project," said County Board Chairman Barbara A. Favola (D). "I think this is what the community needs to do. It's creative, it's smart growth, it's right near the Metro. It gives us community benefits that won't be achieved until we do this."

Public-private partnerships of this kind have been successful in urban areas such as Chicago, New York and St. Louis, but the model is still relatively uncommon in the Washington region.

Church officials said they arrived at the decision to push for a mixed-use development when it became clear that the $4 million in needed building maintenance and repairs was simply out of their financial reach. Church members concluded that the best way to preserve their congregation was to use the church's valuable property -- it is a half block from the Clarendon Metro station and is valued at about $10 million -- as equity for a loan to finance the construction of a smaller church and affordable housing.

Once a suburban mega-church that boasted 2,000 members in the 1950s, First Baptist today serves a total of 400 members split among four congregations -- two that speak English, one Vietnamese and one Spanish.

With that in mind, the new design calls for reducing the chapel by about half, to 400 seats, and building a 10-story high-rise known as the Views of Clarendon on top.

The only reminder of the church's past would be its steeple, which will be incorporated into the new building.

Church officials say the plan is the perfect marriage of available resources, allowing them both to further their ministry work in a more cost-effective building and help fill a critical community need for affordable housing.

Of the 70 affordable housing units, 64 will be designated for those making no more than 60 percent of the area's median income, or $52,000 for a family of four. Six apartments will be set aside for those making no more than 50 percent, or $43,000 for a family of four.

The project has been tweaked by planners since it was first brought before the board in July. The revised plans call for a building that is about six feet shorter, coming in at slightly taller than 96 feet; more of the apartments are designated for affordable housing, and the architecture was improved, officials said.

"We're thrilled," said Jerry Morris, a church trustee.

"It's now a better project than the one we originally conceived."

Better or not, the plan has not been well received by some neighbors in the adjacent Lyon Village community who opposed the size of the high-rise and feared that the project's approval would unleash a flood of developers seeking permission to put more high-rises in and around the neighborhood. Many of those neighbors voiced their concern before the board on Saturday.

Mary Renke, one of many Lyon Village residents who opposed the development, argued that the board's vote to approve the building's height is a violation of the county's zoning ordinance.

"They're breaking the law," said Renke, who spoke before the panel on Saturday.

She said she and others are also concerned that the project -- which will rely on some county funds to construct housing in the same building as a sanctuary -- might be unconstitutional. The board approved a $4.5 million loan from Arlington's Affordable Housing Investment Fund that will be repaid at 3.5 percent interest.

"For me, this is not about affordable housing, but about a church trying to get the county to help pay for a free place of worship, which is why the building needs to be so big," Renke said.

Many parents whose children attend the Child Development Center also spoke at the meeting. About 185 children receive day care at the center each weekday.

While most parents vigorously opposed the project when it was first proposed, they came out Saturday to support the mixed-use plan, swayed, they said, by church leaders who responded to their concerns.

"We're pleased," said Janet Rice Elman, who was selected to represent the parents' interests in discussions with church and county officials.

"It's good for the community and good for the long-term sustainability of the Child Development Center."

Officials said construction of the new building is estimated to begin in July and take approximately 18 months to complete.