The red-brick building going up across the street from Inova Mount Vernon Hospital is not your standard construction site.

Before work begins at 7 a.m., a prayer is said. Lunch is accompanied by Bible study. When hammer hits thumb, the harshest word uttered is "ouch."

At this site, and four others across Northern Virginia and Maryland, the construction workers are all Jehovah's Witnesses volunteering weekends to build a 4,000-square-foot assembly place -- or kingdom hall, as their buildings are called.

More than 300 people, ranging from teenagers to those in their seventies, have chipped in on the carefully orchestrated project that will go up in just five weekends from start to finish. The building is expected to be finished next weekend, and once a use and occupancy permit is granted, 400 Jehovah's Witnesses from three congregations will share the hall.

Most members of the construction crew members are neophytes such as Luis Iglesias; his wife, Ana; and daughter, Cynthia, 14. Iglesias, a cook, said he was a little uncertain whether he could be of any help.

"But I walked in the first day and they directed me to a group," Iglesias said yesterday, taking a break from installing insulation. "Next thing I knew, I was helping build trusses. It was a hot day, but a great day."

Others are becoming veterans. Just 17, Eugenia Skiles was installing insulation yesterday on what she said was the seventh kingdom hall she has helped construct.

"My dad started taking me when I was little," said Skiles, who has her own, pink hard hat. "It's nice being with people who follow the same religion."

The reliance on volunteer labor and some contributed materials -- the forklift, for example, was donated by a Jehovah's Witness -- allows the sect to keep construction costs to $65 a square foot, said Joe Verbos, a member of the Maryland Building Committee, which has overseen the construction of 10 kingdom halls in the Washington area in the past three years. Using all professional labor would cost $300 to $400 a square foot, he said.

The money saved, Verbos added, can be directed to the group's core mission of proselytizing.

The Mount Vernon kingdom hall will be one of 59 in Northern Virginia, Southern Maryland and the District, all built by volunteers. All the buildings are essentially the same, becoming easier to build with practice.

The trick to erecting a building so quickly with so many unskilled workers is in organization and division of labor. Visiting the site is like watching a wall of television screens, each tuned to a different channel.

In the main assembly room, workers hammered plywood for a stage floor. Two people strung electrical wire in the ceiling. Several men checked the newly installed drywall for moisture, while others unfurled rolls of wallpaper. One woman did nothing but sweep.

Outside, men troweled bricks into place. Sitting behind them were women who handed them the bricks, and around the corner another group erected scaffolding for the next phase.

"You can take a handful of bricklayers, and they lay brick twice as quick," said Glenn Parks, who oversees the project. "If this were a regular job, the bricklayers would have to do a little of that work themselves."

The site off Richmond Highway was chosen because about 300 members live within a mile. They currently meet at two kingdom halls in Alexandria and Springfield.

"We want to be able to serve the community at large," said George Bracamonte, another building committee member. "Bible preaching is the work we do."

Ana Iglesias, right, helps move buckets of mortar as she and hundreds of other Jehovah's Witness volunteers build their assembly place in Mount Vernon.The 4,000-square-foot building will go up in five weekends, with the help of construction volunteers. The structure could be finished next weekend.