If you heard that real estate sales have been booming hereabouts, believe it. Despite the rough January and February weather, multiple listing sales reported by area real estate boards hit a record 5,619 transactions. That report was compiled by housing economist Michael Sumichrast, who added that the total for the first two months of this year was 25 per cent higher than the total for the same two months in 1977. Meanwhile, listings of existing houses for sale dropped 3 percent in the metro area-to 11,455. The decrease was particularly strong in Montgomery County - 12 percent to 2,705 units. In Northern Virginia, sales totaled 3,004, an increase of 39 percent over the same period in 1977. Prince George's County had a 20 percent increase. No statistics are included for the District in this report because the Washington Board of Realtors only recently began a multiple listing service.

An apartment building at 1715 P St. NW was sold recently by Mr. and Mrs. D. Alperin for $250,000 to Twenty-first Newport Limited Partnership.

A fine old (1760 vintage) house in plainfield, Conn., is scheduled for dismantling and shipment for reconstruction on a 5-acre lot in the Dominion Valley Hunt area of outer Fairfax County. The large frame house was on the market for about $55,000 and came to the attention of folks at Golubin & Warwick realtor firm in Alexandria. They liked it and decided it was worth the effort to dismantle but saving the timbers, stone, bricks, beams, flooring, paneling, hardware and doors. The roof and siding will be discarded. The plan is to begin the dismantling, moving and reconstruction within a few months. The redone house is expected to be ready for sale next spring and the tentative price is $375,000. India Benoit is in charge of the project for Golubin-Warwick.

Clarence F. Donohoe Jr., trustee, and others recently sold an office building at 1680 Wisconsin Ave. NW for $825,000 to 1680 Wisconsin Avenue Associates.

Waren Katz, the builder who is constructing a design house for his own family, estimated that he saved at least 60 days in construction time during the winter by using an all-weather wood foundation system. His lakeside house was designed by Hugh Newell Jacobsen. The American Wood Council and Gulf Reston, Inc., participated in the planning to emphasize wood products and systems in a contemporary house. Katz said that the foundation was placed in December and the house now is under roof. He added that a masonry foundation house next door was started by his farm a month earlier but still is in the inital stage of construction.

In downtown the other day to attend a meeting at the National Corp. for Housing Partnerships, builder-developer Thomas P. Harkins said that he had used the Metro line from Silver Spring. "It was convenient and economical because the Metro station is within a short walk of my office in Silver Spring," he said.

Appraiser Alfred Jarchow's February report on resale house prices in Montgomery County showed prices up 2 percent over the December level and 3 percent higher than last November. He said that the annual rate of increase, which dropped in January, was back up to 8.7 percent. The median price was $63,000. He added: "A strong upward price trend was seen in all house types. This, of course, is the beginning of the season when, typically, the market for homes is strongest and the biggest price gains are made." On that score, marketers of new houses reported recently that they had their heaviest sales in February and March last year. The same strong trend in new home sales was reported again this year for those months.