For the 20 years that Ann Haffner has lived in in Old Town Alexandria, the one thing she has wanted has been a grander bathroom to replace the tiny one crammed into the master bedroom of her 173-year-old Federal style home on North Fairfax Street.

But Haffner and at least two dozen other property owners who want to make changes to buildings they own in Alexandria's old and historic district have had to temporarily shelve their plans.

For the first time in its 37-year history, the city's nine-member Board of Architectural Review, which in most cases has the last word on building in Old Town, has been unable to muster a quorum of five members needed to review building plans.

Critics have blamed political bickering about who gets to sit on the board for the absenteeism, but others have blamed the lure of summer vacations. Whatever the cause, the upshot has been a noticeable slowdown in the peak construction period, according to local contractor Kevin Corbett, whose business is concentrated in Old Town.

"I'm steamed," said Haffner, who sat on the architectural review board herself for 12 years until 1981. She described herself as a "mainstay" on the board, and said she hardly ever missed a meeting until her last year, when she worked in Maryland.

Haffner says the board's failure to reach a quorum for its last two meetings on July 20 and Aug. 3 is "totally unfair to the public. I think they have a responsibility."

Speculation abounded yesterday that the board's quorum problems were really a thinly disguised boycott by some of its members, who are miffed by Alexandria City Council's decision last June to reconstitute the board. A new review board is expected to be named when the council meets on Sept. 13.

The change came after a storm of controversy generated by citizens groups who complained the architectural board was destroying the district's historic ambiance by encouraging too many contemporary designs amid the Victorian, Federal and other architectural styles that dominate Old Town.

"I assume that they are, justifiably, upset," says Vice Mayor James P. Moran Jr. about board members who may be boycotting.

Member Daniel R. Bairley said he missed one meeting because he was vacationing in Michigan and was at a planning commission meeting in Prince William County for the second. "I'll be there," Bairley said of the next meeting, which is scheduled for Aug. 17. Two other board members, William Hurd and William Seale are on vacation, according to their business offices, and could not be reached for comment about why they missed the past two meetings.

The board meets more regularly than the city's 40 other standing boards and commissions--twice a month--and unlike most, doesn't take a summer break.

The board's acting secretary, Uwe Hinz, said the quorum situation has been further exacerbated by city council's failure in June to replace four board members whose three-year terms expired. Two of those members, architects Ray Lewis and Charles Richards, have refused to serve because their terms have ended.

But Assistant City Attorney Barbara Beach said yesterday that nothing in the code prevents board members, even if their terms have expired, from serving until they have been replaced.

Board member Duncan Blair, who was present for the last two meetings, says that it is likely a quorum will be reached when the board meets again Aug. 17.

"I plan to be there," he said.