Prudential Life Insurance Co. has sold the 10-year-old Webster House apartment building at 1718 P St. NW for $4.4 million to a limited partnership. The 183-unit building is being converted to condominium ownership. In another recent transaction, the Tunlaw at 3900 Tunlaw Road NW was sold for $3 million by L. M. Rich to Tunlaw Cooperative.

The Montgomery County Board of Realtors has purchased a five-acre site on Piccard Drive in the Shady Grove area south of Gaithersburg and plans to build a two-story building to serve its 5,200 members. The board is currently located in Kensington.

SHORTLY: Patricia Mathews has moved from a top property management position at Columbia Plaza, which is being sold and is expected to go condo, to the 1,072-unit Promenade apartment building in Bethesda as general manager for owner Nathan Landow. . . Golubin & Warwick Inc., headed by 30-year-old Gregory Golubin, next week is moving from Old Town Alexandria to a new office in the reviving Del Ray-Potomac Yards section of Alexandria and another branch in Potomac. . . Thomas Caldwell, the soft-spoken Virginian who retired recently as director of training and education at the National Association of Home Builders, is back there working part-time and finding jobs for Job Corps graduates in Mayland and Virginia.