The Pennsylvania Avenue Development Corp.'s plans to tear down one of the avenue's worst eyesores, the vacant Kanns Department Store, have run into opposition from the District of Columbia's Joint Committee on Landmarks.

The Landmarks Committee - an unpaid, intergovernmental agency - has recommended that the District refuse to grant a permit to demolish the building.

Beneath the sagging gray aluminum panels that now sheath the Kanns building is a classic brick facade that might be preserved, say committee staff members.

The committee members are also afraid the site will be used as a parking lot until the PADC is able to carry out plans to build a housing project on the site.

Earlier this year, PADC paid $4,725,000 for the Kanns site, which faces Pennsylvania Avenue at 8th Street, NW.

Since the Kanns store closed in 1975, the building has been empty. It's basement is flooded as a result of nearby Metro construction and the building is structurally unsound, say PADC staff members.

The housing project for the site is several years away; in the meantime the agency hopes to develop a temporary plaza on the site. Tearing down the vacant building will be a sign of progress toward revitalization of the avenue, say PADC officials.

The Kanns store was "an extremely handsome building before the facade was put up," said Nancy Taylor, a staff member of the National Capital Planning Commission who works with the Landmarks Committee.

Agreeing with PADC officials, Taylor said there is "some question" about how much of the building's original exterior remains below the aluminum panels which were installed in 1959.

The District is expected to hold a public hearing on the application for a permit to tear down the building. The D.C. Commission on Fine Arts has recommended demolition.

New historic preservation legislation now pending before the city council would allow the city to permanently prohibit demolition of historic structures or any other building in an historic district.

PADC officials, who are fighting to have the Pennsylvania Avenue corridor they are responsible for excluded from the new preservation law, contend the measure could become a major obstacle to new construction in downtown Washington.