The Charles E. Smith Companies, one the area's major builders, developers and managers of office and apartment properties, is "seriously considering" a move from its downtown headquarters to new offices in Crystal City.

Robert P. Kogod, president of Charles E. Smith Management, Inc., has confirmed a report that the Smith firms - which include Charles E. Smith Building Corp., headed by Robert H. Smith - may move in 18 months. He said the move is being considered because it would place top personnel in the Crystal City area, where the firm has already developed more than 20 high-rise office and apartment buildings on the Route corridor near National Airport.

The Smith firm has long-range plans to develop a complex of buildings on or over adjacent land owned by Richmond, Fredericksburg and Potomac Railroad Co. The project could be four or five years down the track," Kogod said.

With partners, Smith firms own and manage approximately 14,000 rental apartments in Virginia and the District. They also own and manage 15 downtown office buildings, including 1101 17th St. NW., the company's headquarters.

A move from the downtown building in the District to a new building in Crystal City would not occur until late 1978 or early 1979, Kogod said.