When they got bogged down in the middle of building an addition to their Silver Spring house, Marty and Maggie Bedrosian overcame their pride and invited a dozen friends over for an old fasion "house-raising".

By the time the two-day affair had ended last Sunday afternoon, the group had put up skeleton walls and portions of the roof for a 16-by-24-foot living room addition and had polished off several bottles of champagne and a quantity of Armenian basterma and eggs. Many of the helpers arrived at the house on McKenny Street Saturday, threw down sleeping bags that night, and on Sunday went to work again on the project, an extension to the post-World War II bungalow once owned by Marty Bedrosain's parents.

"I got a big kick out of it, I really did," said Marty Bedrosian, an electronics designer for a Gaithersburg company. Several days before the house-raising, however, Bedrosian had confessed some trepidation about sending his paper-pushing friends up rickety ladders, saying, "I"m 20th century urban American . . . and I have visions of this huge liability."

But it was those friends who suggested the working bee, possibly out of sympathy for the Bedrosians, who had spent a year and a half simply erecting a four-foot-high platform to support the addition.

So, Marty and Maggie scheduled the event and, with the added enticement of chili dogs, bubbly wine and imported ale, attracted a variety of friends who displayed varying degrees of enthusiasm.

"This Christian work ethic stinks," groaned Larry Mayfield, 40, bringing his hammer back for a half-hearted swing. Mayfield, a foreign affairs analyst from Manassas, arrived at the house Saturday with Christmas tinsel draped around his neck and a pink bow pasted to his forehead in honor of the Bedrosians' eighth wedding anniversary.

Joining Mayfield on the project were Margaret Bedrosian's brother-in-law, a personnel director from Rockville; a 38-year-old research technician from Australia; a radio announcer from WJMD in Bethesda; a machine tool supervisor who lives on a boat in Baltimore; a jewelery store owner and an oral surgeon--who brought his vacationing father and brother for a couple hours of work.

"We don't have any idea what we're doing and that makes it more fun," Marty Bedrosian said in the middle of Saturday's somewhat organized hammering and measuring.

He laughed at the thought of comparing the weekend's efforts with the barn-raisings and corn huskings of Early American neighborhoods. "It's great if the guys you've got putting up the barn know what they're doing," he said.

Bedrosian hopes to finish the addition by next spring. It will have a fireplace at the far end, a dining area and a connecting outdoor deck, all for about $6,000, less than half of what a professional builder would have charged, he said.

The house-raising, Bedrosian said, was less a construction effort, than "an excuse to get together with the gang."

Indeed, the weekend bee spawned yet another party excuse. Maggie Bedrosian, an independent communications consultant, filmed portions of the construction and already has plans to invite the whole group back for another bash--this time to watch home movies of their effort.