Members of the Loudoun County Board of Supervisors frowned Wednesday night at a developer’s request to more than triple the number of houses it could build on land west of Dulles Airport, a potentially ominous sign for home builders hoping to reenter the suburban market.

Under existing zoning, Cor­belis Development NoVa LLC of Ashburn can build 245 single-family detached homes on 737 acres it owns south of Route 50, part of a more than 4,000-acre community it is building called the Greens at Willowsford on what is now rolling farmland.

Corbelis requested a zoning change that would allow it to build 802 homes, 350 of which would be restricted to senior citizens. In exchange, the company offered the county improvements the company valued at more than $15 million. They included 21 acres for a new elementary school, a 60-acre park, and road upgrades that some residents say are badly needed.

The Loudoun board approved similarly large requests with regularity when the housing market was booming. From 2004 to 2007, the board approved 20,654 net new housing units through rezoning, according to the Loudoun County Department of Planning.

Applications went on hiatus during the housing collapse and financial crisis, but now developers have returned looking for more density, submitting applications that would add some 8,000 units.

Judging by the experience of Corbelis, some of those applications are likely to face resistance.

Supervisor Janet S. Clarke (R-Blue Ridge) said the county should not have to approve more housing units for residents to get amenities like a new gas station, restaurants and shopping. “Builders should look at what communities need,” she said. “Not just rooftops.”

Supervisor Ralph M. Buona (R-Ashburn) defended the board’s reluctance in recent years not to approve too many units. In 2012, the board approved no net new units and last year it approved 531, but 943 that had been approved came off the books. “This board to date, in our two years in office, due to rezoning, has approved negative 412 new units,” Buona said.

The Piedmont Environmental Council, an advocacy group, issued an alert to supporters before the hearing. Some of the applications are along a proposed road, the Bi-County Parkway, that has sparked opposition amid suggestions that it would lead to the construction of an outer beltway.

“If there’s one thing that Loudoun County and our Board of Supervisors should have learned from our earlier explosive growth, it’s that adding more development to the pipeline will further degrade our community with sky-high debt and lower standards of living,” wrote Ed Gorski, Piedmont land-use field officer.

Packie E. Crown, a consultant who represents the builder, said that a financial study demonstrated that with the zoning change the project would bring the county $56.6 million in economic benefits over 20 years and needed improvements.

“This application responds to the needs for parks, schools, roads and housing choice,” Crown said at the hearing.

Most of the board members present, however, said they saw little reason to approve new housing units in an area designated as a transition zone between suburban and rural parts of the county.

The board is scheduled to vote on the Corbelis application next month.

Capital Business is The Post’s weekly publication focusing on the region’s business community.