How do you move a pair of landmark 178-year-old rowhouses with a combined weight of about 300-tons?

Slowly, carefully, and very expensively, as George Washington University and the moving engineering firm of William B. Patram demonstrated last weekend. At 6:30 Saturday morning the two 2 1/2-story houses, which together measured 42 feet wide and 34 feet deep and which were braced by wood and steel supports for the trip, started the three-block journey from their original site on 19th Street between F and G streets NW.

Mounted on huge, wheeled dollies, they were pulled by Army surplus tractors to a new site about 12:30 p.m.

This week, wooden blocks will be placed under the house so the wheels can be removed, according to Patram. Then, new foundations will be constructed.

The cost of the move, including consultant fees, site preparation and new foundations, will total more than $250,000, according to university officials. At additional cost, the houses will be restored and used as single-family residences, probably for university staff members.

The expensive trip was necessary because the university wants to build a revenue-producing office building for the World Bank in the block surrounded by 19th, 20th, F, and G Streets.

At D.C. Zoning Commission hearings on the proposal, many neighbors opposed the plan - including Mildred Obear who owned and lived in one of the recently moved houses. Later, Obear sold her home to the university - on condition that her house, and its twin next door, be preserved.

According to the plan approved by the Zoning Commission last October another landmark house on the block, now occupied by the F Street Club, will remain on its site with the new building constructed around it.

The two relocated houses were built by John Lenthall, who later became a construction foreman at the U.S. Capitol and died in 1803 when some masonry arches at the Capitol collapsed on top of him. The Lenthall houses, some of the earliest remaining in the city, are considered good examples of early nineteenth century working class dwellings.