It's an unobtrusive building to have weathered such a storm, but after 15 years of controversy the $6.5 million Mount Vernon House for senior citizens--the last piece in a suburban jigsaw puzzle that brings together town house cul-de-sacs and doorstep medical care--is nearly completed.

"It's bee-yootiful," says Mary Hardy, who moved into the house three weeks ago.

"I'm frankly delighted with it," says Jane Eyster, president of the once-wary neighborhood homeowners' association. "I've had three mothers already call and ask if I thought anyone there would be interested in taking care of children part time so they could go back to work."

The apartment building, a four-story irregular doughnut amid the River Farms town houses, is part of a 72-acre planned-development housing project on Tiswell Drive in eastern Fairfax County offering what developer S.L. Hinson calls "the whole nine yards" of health-care services.

In addition to the federally subsidized apartments for the elderly, the Mount Vernon professional community includes doctors' offices and a 130-bed nursing home, all developed by Hinson and his son Laing; community mental health and public health clinics and, a few hundred yards away, Mount Vernon Hospital.

"When we came up with the plans, the idea of co-locating medical buildings and housing was being talked about a lot, but nobody was doing it," says Laing Hinson. "It was a massive rezoning battle. . . but we finally made everybody happy."

"It's as much a compliment to Sam Hinson's stick-to-it-iveness as anything," says Fairfax Board Chairman John F. Herrity. "He spent practically his whole life on this project."

"Well, the last 10 years," says Hinson, a former Air Force colonel who began buying and selling real estate after his retirement from the Pentagon in 1970. "It's the history of my career as a developer."

The battle for the Mount Vernon project began in the late 1960s with the plans for a regional hospital. "It was the longest unresolved zoning issue in the county," remembers Sam Hinson, who acquired the land in 1971. "There were high-rises proposed like a Crystal City. And that set the trend; anybody who came in here with a plan ran into trouble."

On the one hand, there were mulish federal-funding delays, finally resolved through the coordinated efforts of Hinson, Herrity, former Democratic Rep. Herbert E. Harris and his Republican successor, Stan Parris. And on the other, there were coordinated objections from Mount Vernon-area homeowners, who feared both commercialization and lowered property values.

"I think people were concerned when they heard the housing was to be subsidized," says Mount Vernon Supervisor Sandra L. Duckworth. "But it's a very exciting development, the first move in this district in the direction of housing for the elderly. Mount Vernon has an unusually high percentage of residents over 55"--about 15 percent.

It was a campaign of small treaties: "We agreed no buildings would be taller than the hospital," says Laing. "And we tried to give the apartment building a town house facade." He points through a cul-de-sac of brick houses toward Mount Vernon House. "The windows are staggered" to avoid an institutional look, "and by closing it up toward the houses, it doesn't look much bigger."

Of the 72 acres Hinson acquired, part of a horse farm still operating just north of the development, 29 acres were donated to the county park authority as a wooded buffer zone. Two sections of town houses, Briary Farms and First River Farms, were commercially developed, and the houses have sold conventionally for up to $140,000.

The apartment building itself, designed by Gus Costa of Reston's Environmental Design Associates, is a departure from the typical corridor system. "It's too easy never to meet anyone that way," says Laing Hinson.

Instead, each apartment opens onto a balcony in the atrium, rather like a topless Hyatt Hotel. Iron railings are topped with wooden flower boxes, to be planted by the tenants, and each floor is bisected by a catwalk. Five apartments were prepared for handicapped residents, with wide passages and shower stalls that wheelchairs can get into.

HUD has fixed the market rate for Mount Vernon House rents at $550 for one-bedroom apartments and $615 for two. Residents pay 30 percent of their incomes and HUD subsidizes the rest.

It is not entirely coincidental that the nursing home and the apartment building have the same number of units. Eventually, Sam Hinson hopes, a "buddy system" might develop between residents of the apartments and nursing home patients. The nursing home buddy would receive Christmas cards and occasional visits, he says, while the apartment dwellers might "lose their fear" of moving into the home.

Ironically, considering the controversy, Mount Vernon House may wind up as a source of continuity. In an area of young families, many impermanently settled or on military tour, some say the elderly persons may provide the community with balance and experience.

"That relationship will have to evolve, it's not something you can force, but I can foresee that as the community grows older, it might become even more transient, more rental property," says Jane Eyster. "A sense of permanence could be very important."