Unless preservation adovcates can convince the owner otherwise, a 147-year-old house at 2030 I St. NW. part of a block known as Red Lion Row, may be demolished after July 15 when a 30-day reprieve runs out.

Under a "gentleman's agreement," allowing time for negotiation, the Howard P. Foley Co., an electrical contracting firm that owns the building, had agreed to wait at least until July 15 before going ahead with plans to demolish the house.

The Foley Co. applied for a demotion permit on the house last November. Because the building was a designated landmark, a hearing was held by the Joint Committee on Landmarks of the National Capital. The committee ordered a 180-day delay, which ended June 25. On June 14, Lorenzo Jacobs, who serves as historic preservation officer for the District, held a meeting of all parties interested in the case.

The delay in demolition provision, an amendment to the D.C. building code, was enacted in 1973 "to permit the state historic preservation officer . . . to negotiate with owners, agencies and interested citizens to find ways to preserve the building."

The 30-day reprieve in demolition, worked out at the meeting, gave preservation advocates and Advisory Neighborhood Commission 2A, which represents the West End-Foggy Bottom area, time to gather information they hope will convince the owner to let the building stand.

The house at 2030 I St. is one of five buildings that the Foley Co. owns in the block. According to John Selinger, the company's treasurer, the properties were acquired over the past several years for a total of about $1 million.

If and when the 2030 I St. house is torn down, the company intends to use the space for parking until other houses are torn down, at which time it would construct a headquarters building, according to Selinger.

"We've been in business at this location since 1923," said Selinger. "We're an expanding company. We intend to build out own building, to take care of our needs. We have our needs, and we have some rights, too."

Though the house at 2030 I St has been listed as a landmark for several years, the entire south side of I Street between 20th and 21st Streets, known as Red Lion Row because of the Red Lion pub in the block, won landmark status in January.

Some of the other property in the block is owned by George Washington University, which had included the block in its master plan.

Robert Dickman, the university's assistant treasurer for plans and construction, confirmed that the university was interested in buying properties on that block. The university would use the space to build an office building and rent it to a non-university tenant, Dickman said.

The university has embarked on a program of building and renting to raise funds, said Dickman. One of its office buildings along Pennsylvania Avenue is occupied by Pepco, and another is occupied by the National Academy of Sciences. The university plans to build another building on the square between F. G. 19th and 20th Streets and rent it to the World Bank.

"Our real estate is the equivalent of an endowment," said Dickman. "By developing commercial property we can help keep tuition lower."

Dickman said the university also sees I Street as the entrance to the campus. Whatever building was eventually put up there would have an open arcade at street level to pull people into the campus, according to Dickman.

Two Washington architects, Thomas B. Simmons and Arthur Keys, working under the auspices of the Committee of 100 on the Federal City, have submitted to the university a design for an entrance to the campus that would preserve the buildings on Red Lion Row. The plan calls for the gaps in the row, created by past demolitions, to be filled in with compatible structures. A modern structure would rise behind the I Street houses - a solution similar to the one worked out for Lafayette Square.

"We would consider some form of this plan if we owned all the buildings on the block," said Dickman.

Selinger said the university has never asked the Foley Co. "to sell these buildings, and we're not considering selling them at this time."

Red Lion Row is "the only block along Pennsylvania Avenue which had retained a great deal of its 19th century fabric and scale," said Nancy Schwartz of Don't Tear It Down, a local preservation group.

"Every other block on this portion of the avenue already is interrupted by a major 20th century highrise building of incompatible scale and materials," Schwartz testified at the hearing to make the row a landmark.

The triangular park in front of Red Lion Row was the original site of the city's Western Market, which was established there in 1803. Most of the people who lived on the block facing the market were merchants and artisans, many of whom kept small shops in their homes.

In the 1870s, Alexander "Boss" Shepherd, the District's territorial governor who also speculated in real estate, built a row of four "Italianate" houses with mansard roofs. Three of the houses are still standing. The House at 2030 I St. was built in 1830, and is considered a fine example of late Federal-style architecture.

Among the information that the preservationists are gathering during the 30-day reprieve are facts about tax benefits the owners would gain retaining the building, according to ANC Commissioner Ann Loikow. They will also try to interest other buyers in the building, Loikow said.

"If this row goes, there will be a Chinese wall across Pennsylvania Avenue," said Karen Gordon, founder of a student group called the Committee for the Campus. "No one knows there's a university behind there. I Street could serve as the gateway to something special - an urban campus."