The Fairfax County Board of Supervisors on Tuesday granted unanimous approval to a Baltimore developer’s plans for an assisted-living complex on the former site of a beloved ice cream stand in Great Falls.

The vote followed an intense debate that split the semi-rural community in recent weeks. About two dozen speakers appeared at the Board’s regular meeting Tuesday, with supporters saying that the developer’s proposal for the Brightview assisted-living complex on the former site of Thelma’s Ice Creamwould be a harmonious and necessary use of the land in a county whose elderly population is growing. But opponents argued that the plan would wreck the neighborhood by cramming a huge medical care facility into a tiny parcel and open the door to further commercial development.

“Some of our neighbors are frightened,” said Robert Lundegard, a representative of the Friends of Colvin Run Mill who spoke in support of the project. “We respectfully request that you set these fears aside.”

But Kimberly Thachuk called the project a “monstrosity” that represented the victory of special interests over neighborhood concerns. Like several others, Thachuk accused their own neighborhood representatives in the Great Falls Citizens Association of selling them out.

Supervisor John W. Foust (D-Dranesville), who represents the district, gave his support to the plan and rejected criticism that the project had lacked transparency. Foust said the senior care complex’s project had been well vetted in many forums, including informal meetings with the developer and two town hall meetings he hosted in June and last Thursday, and that the developer had been extremely sensitive to neighbors’ concerns.

“I know that this has been a difficult application,” Board chairman Sharon S. Bulova (D) said moments before the vote.

The matter came before the Board on Tuesday after the company, Shelter Development LLC, asked for a special zoning exception to build an 94-bed, assisted-living home at 10200 Colvin Run Road. Twenty-six of those beds would be reserved for people suffering from dementia. The land, which is slightly more than 3 ½ acres, is zoned for both residential and commercial uses, with 83 percent of the new complex to be located on the commercial side.

Gregory A. Riegle, an attorney for the developer, told the board that the one- and three-story buildings would be no taller than 40 feet, and they would be built in the craftsman style to blend into their surroundings. He also said such assisted-living complexes do not generate a lot of traffic.

“This is not a commercial use. This is a housing use,” Riegle said, adding that opponents were wrong to say that its approval would open the way to greater commercial development in Great Falls. He also said the developer has agreed to 27 modifications sought by county planners and neighbors as a condition of approval.

These included reducing the size of the planned building on the residentially zoned portion of the propery by 5,000 square feet from nearly 14,000 square feet to about 9,000 square feet. The developer also modified the building on the residential portion to resemble two manor-style homes, including chimneys and gables, agreed to move the building back from property lines, and to perform additional landscaping to screen it.

The Planning Commission had also approved the project, as did county planning staff following further modifications.

Dianne Van Volkenburg, who is chair of the Great Falls Citizens Association, told the Board that Shelter Development had been a good citizen in trying to inform neighbors of its plans and modify them to reduce objections.

But Thaychuck accused the developer of shoehorning a huge complex into a property that, without a special zoning exception, would only be able to have a much smaller commercial use on part of the property. She also said the Great Falls Citizen Association represented only a small portion of the community.

Her husband, Joseph Sartiano, who formed the “No to Brightview” group, said nearly 300 people had signed a petition against the development, which would boost density on the propety by almost 20 percent. Sartiano accused the Board of selling out taxpayers to the highest bidder, quoting George Washington as saying that “Few men have virtue enough to withstand the highest bidder.”

“This was a done deal,” Sartiano said in a brief interview afterwards. He acknowledged that the project has been divisive in Great Falls, and he suggested that the fight may continue in court. “I’m not stopping today,” he said.