The Fairfax County Board of Supervisors has approved construction of a six-story office building in the Fairfax Center area four years after the original rezoning application was filed.

The building will be constructed along Route 50, west of Waples Mill Road. Access will be from Random Hills Road.

Six weeks ago, the county planning staff recommended denial of the application for rezoning of the site even though the county's planning commission had approved the developer's original plan for a larger building on the site three years ago. That application was never acted on by the board of supervisors.

Now Hersand Builders Inc., a Fairfax development company, has agreed to pay $250,000 into a county road fund that has been set up to pay for future off-site road improvements expected to be needed as development in the Fairfax Center area at Route 50, West Ox Road and I-66 continues.

Hersand President Herbert L. Aman said this week that he was surprised by the recent troubles with Fairfax County planning staff over the proposed building. Hersand was the original applicant in 1980.

"We thought we were under the floor area ratio density where you are required to make contributions to the road fund," Aman said.

After meeting with county planning staff members and Springfield Supervisor Elaine McConnell, within whose magisterial district the project lies, Aman said the staff problems with the proposal were resolved. The staff recommended approval of the project before the board of supervisors gave it the green light.

The 2.9-acre site involved is small compared with massive rezonings that have taken place in the past two years in the Fairfax Center area, but must conform to the same standards that apply to the larger projects. Since the application was filed in 1980, the 50/66 Task Force report designed to guide development in the area has been completed, and major rezonings have been approved in the I-66/Route 50 corridor. The Hazel/Peterson Cos. last week marked the beginning of construction on its 620-acre Fair Lakes operation with a gala celebration.

Of major significance to the county as a whole, according to county officials, has been the creation of the road fund, to which developers are expected to contribute to provide for future off-site road improvements in the area. That fund is expected to help prevent traffic problems in the Fairfax Center area similar to those that plague other major areas of intense development in Fairfax.

Although the original application called for a 90,000-square-foot building, Aman said this week that the building will be only 81,000 square feet. Construction is expected to begin by late spring of 1985. Aman this week hired the architectural firm of Davis and Carter to design the building. That firm also is designing other major projects in Fairfax Center, including the corporate headquarters of Hazel/Peterson Cos.

"We plan to give special regard to the architecture of the building to help create an image for the building's major tenant," Aman said. More than 40,000 square feet will be leased to First American Savings and Loan Association for its corporate headquarters, which is now located in Woodbridge.

Hersand Builders early this week opened a major new office building housing the Opticians Association of America at a project known as Providence Hill near University Drive and Route 237 in Fairfax City.

Hersand also developed the Joshua Cofer Gunnell building, behind the historic Oliver House in Fairfax City.

Aman will end a year as president of the Home Builders of Virginia in the next few weeks. He was primarily a homebuilder until six years ago, when his company ventured into commercial development. He said he "still develops residential lots" but generally sells those ready-to-build-on lots to other builders.