Rising costs of single family housing are expected to trigger a need for educating the public about the option of condominium buildings and attached housing units, a Washington area developer told fellow builders meeting here.

Martin Poretsky, president of the Suburban Maryland Home Builders Association, described the difficulties of creating a subdivision of a hundred $90,000 houses in Fairfax County - "where we wanted to save trees in a wooded area."

He said innovative housing clusters are needed to produce a choice of smaller, attractive homes in the medium-price range. He added that a grouping of attached units could attract buyers - priced out of their first choice of a single house on a plot of ground - "if the developer is able to provide a private patio garden area" to satisfy the need for some land.

A partner in the firm of Poretsky Starr, Inc., Poretsky participated in a panel discussion with a California developer and a Boston-area mortgage banker at the annual convention of the National Association of Home Builders.

Frank Hughes, an executive of the Irvine Development Group in southern California, saidnew home buying has resumed "as usual, after the superbowl." But he said environmental controls have driven up the cost of available building lots and put many single-family houses over the $100,000 level.

Morton Weiner of Waltham, Mass., said new construction in the Northeast did not keep pace with the record pace of single-family home construction in other areas of the nation last year. "Our increase in new construction is steady but slow," he said. "So far the supply of mortgage credit is adequate despite slight increases in lending rates."