In a decision that may retain as many as 1,000 Cambridge apartments under rent control, a Middlesex Superior Court judge last week overruled a lower court finding that threatened the city's strict regulations restricting condominium conversion.

Superior Court Justice James J. Nixon ruled in a partial summary decision that the Cambridge Rent Control Board could order Irene D. Polednak to acquire a special permit from the city before purchasing her rent controlled apartment and occupying it as a condominium.

Polednak last year challenged the rent board in Middlesex's Third District Court, charging that the city agency was unfairly applying a 1979 ordinance limiting condo conversion. The rent board has interpreted the ordinance to require removal permits only of tenants who moved into their units after the law was approved.

For regulation purposes, the rent board thus created a set of city buildings, known as "hybrids," that contain both converted condominium units and rent-controlled apartments. Hybrids account for about 1,000 rental units, or about five percent of the city's tight housing market.

Last year District Court Judge Arthur Sherman agreed with Polednak, who moved into her apartment at 50 Follen St after the 1979 date. In his ruling. Sherman stated that the intent of the ordinance was unclear and that the rent board had no legal right to interpret it.

Nixon finding last Wednesday concluded part of the rent board's appeal of Sherman's decision, which rent board members and tenant activists feared would set a precedent for potential condo owners to by pass the city agency through civil lawsuits.

City Councilor David E. Sullivan who wrote the condo conversion codes, yesterday called Nixon's decision "a substantial victory." He said that "another loophole has been closed in the developers efforts to get around the ordinance."

Fish

Polednak was unavailable for comment last night.

In response to Sherman's statement that the code's intent was unclear, the city council last April passed an amendment to the anti-conversion laws which ratified the rent board's interpretation of the ordinance.

Sullivan said it was unclear whether Nixon used the amendment in reaching his decision, but he added that the ruling gives it "a retroactive effect."

The decision was particularly gratifying, Sullivan explained, because of the "adversity" the rent board had overcome in preparing its appeal. In February, the council's conservative Independent faction and Mayor Alfred E. Vellucci denied City Manager Robert W. Healy funds to hire an outside attorney to file the appeal of Sherman's decision, despite the unified support of the four liberal Cambridge Civic Association councilors.

Nixon's decision also orders the rent board to reconsider Polednak's original petition for a removal permit. Nixon stated that the agency's denial of the permit was based on incomplete records.