The spring frenzy of new-home buying in the Washington area has slowed a bit, with May sales off 25.5 percent from April.

"Home shoppers are catching their breath," said Renay Regardie, president of Housing Data Reports, a monthly survey of the Washington-area housing market. "They're heading for the beach instead of the model home during the weekends."

Sales totaled 3,044 in May, compared with 4,086 in April, she said. But the May total was higher than the 2,587 total for the same month a year ago.

Regardie said more buyers are "experiencing buyer remorse and hesitancy" as they near settlement. A total of 382 would-be buyers, 11 percent of those scheduled for settlement in May, backed out of their house deals, compared with about 7 percent to 8 percent earlier in the year.

"Seasonal patterns suggest that sales will be in the dog house during the dog days," Regardie said. But she predicted they will pick up again after Labor Day.

The U.S. League of Savings Institutions has found in a study of its lenders that singles have a slightly lower mortgage loan delinquency rate than the traditional family borrower. The worst bets for lenders are loans in excess of 90 percent of a property's value, loans to investors and loans to finance condominiums. The lenders' trade group said the safest loans for the industry are those to two-income borrowers and notes for more than $150,000. The survey showed that the most important reasons for delinquencies were unemployment, domestic problems and cuts in income.

A survey last year of 5,000 home buyers has found that more than half of them were seeking tax and investment advantages when they decided to move to a new home or buy their first house, according to the National Association of Realtors.

The real estate trade group also found that 40 percent of buyers moved to new quarters so they would have more room to rear a family, while 30 percent said they were not satisfied with their old neighborhood. Other factors played lesser roles in decisions to move, such as condominium conversion (1 percent), health reasons (5 percent), the desire to move after retirement (7 percent) and the preference for a smaller home after children had grown up and moved away (8 percent).

A total of 18 percent of home buyers moved after being transferred by their employers, while 16 percent moved to change employers.

The typical home buyer last year was 34 years old, part of a two-income household with combined earnings of $36,500, and usually was a married couple with children. Predictably, first-time buyers tended to be younger -- about 31 years old with a $31,000 household income. Repeat buyers tended to be about 39 with a $41,000 household income.

Nearly 90 percent of home buyers bought a detached home, while home buyers under 25 or over 65 were more likely to prefer a town house or a condominium. A total of 84 percent of those surveyed bought existing homes, while 16 percent bought newly built homes.

IN THE BUSINESS . . . The Montgomery County Board of Realtors reports that housing sales for the first half of the year were up 62 percent over the same period in 1985. . . . A total of 22.8 million square feet of office space was under construction in the District at the end of last year, about 14 percent of the 158.5 million square feet being built nationwide, according to a survey by Cross & Brown Co. of Maryland, a real estate brokerage firm. The city absorbed 11.4 million square feet of space last year, which led the nation, and was second in the lowest vacancy rate for a central business district -- 7.6 percent. . . . Construction has started on Fullerton Square, a two-building, 180,000-square-foot office park, at the Newington exit off Interstate 95, which is being developed by Hoskinson and Davis Inc. and Acacia Mutual Life Insurance Co. . . . The Society of Industrial Realtors has changed its name to reflect the work of its 1,600 members, to Society of Industrial and Office Realtors. . . . Mount Vernon Realty and Town Center Realty in Annapolis have merged. Meanwhile, Mount Vernon has opened a relocation office in Frankfurt, West Germany. . . . Construction has started on a 147-room Courtyard by Marriott hotel at the intersection of Research Boulevard and Shady Grove Road, west of the Interstate 270 interchange.

PERSONNEL FILE . . . James F. Tobin has been named vice president of the Silver Spring building firm of Thomas P. Harkins Inc. . . . Peter Speier, district manager of the three Julien J. Studley Inc. commercial leasing offices in the Washington area, has been elected vice chairman of the firm . . . Columbia Real Estate Title Insurance Co. has elected Elisabeth Zajic as vice president and counsel . . . The development firm of Lee Sammis Associates Inc. has named Arthur F. Olecheck vice president and director of finance . . . Douglas F. Moore has been promoted to vice president for Metro Pace Construction in McLean.