NS&T Bank, one of the oldest savings institutions in the city, is seeking to take advantage of broad, newly available tax benefits for preserving old buildings in the restoration of its landmark downtown headquarters.

The distinctive five-story, red-brick-and-stone building with its three-story copper bay and clock tower, at the corner of 15th St. and New York Ave. NW, has been a familiar sight in Washington since 1888. The bank lobby is one of Washington's largest, replete with marble and topped with two naturally-lighted stained glass domes.

NS&T had occupied its present location, prominent along the presidential inaugural route, since 1867 when it began business as the National Safe Deposit Co. of Washington on the ground floor of the three-story Plant's Building that then occupied the site.

Now, seeking more office space than the building and two additions--one built in 1915 and one in 1924--provide, officials of NS&T have decided to build a new nine-story addition along New York Ave. and to utilize the extensive historic preservation tax benefits to renovate the adjoining old building.

Just how important lawyers are in the process was evident during a walk through the now-empty four floors of office space above the first floor last week with Carolyn J. Hamm, an architectural historian and attorney with the law firm of Wilkes, Artis, Hedrick & Lane.

Surrounded by NS&T officials; members of the architectural firm of Weihe Black Jeffries Strassman & Dove; representatives of the George Hyman Construction Co., which is involved in the partial demolition of the inside of the building; members of two interior design firms and a structural consultant, Hamm advised the crowd on what portions of the building should be saved in order to meet the Department of Interior's standards for rehabilitation.

In general, under a series of tax incentives enacted by Congress in 1976, rehabilitation of a certified historic commercial, industrial or rental residential structure whose restoration also is certified can qualify for a 25 percent investment tax credit, which can be combined with a 15-year accelerated recovery period.

"Until the new laws were passed, all the tax incentives were in favor of new construction," Hamm explained. "These try to encourage the private sector to renovate historic properties; they give added life to preservation."

Selected demolition already had been done on the NS&T building by Hyman Construction in order to uncover the original materials and style. "Whatever is of original fabric, you should retain as much as possible," Hamm told the assembled. "You don't have to restore the building to l890, but you must preserve as much as possible."

Pulling up the rugs in the corridors on several floors had revealed marble floors and marble bases. "Save the marble floors," Hamm advised. "If you want a rug over it, that's okay." The Interior Department's rehabilitation standards state that wherever possible, new additions or alterations shall be done in such a manner that if they were to be removed in the future, the essential form and integrity of the structure would be unimpaired.

On the top floor, removal of suspended eight-foot ceilings that were installed in 1954 revealed old but largely preserved columns, moldings, and cornices with eagles adorning the 15-foot ceilings. Those room embellishments, dating from 1915, should be preserved, Hamm noted.

Also, modern-day partitions had been used there to make small offices out of what had been a very large room and larger offices used at one time by the United States Court of Appeals. Hamm advised eliminating the partitions and restoring the room to "the grand space" it once was.

"The idea is to accommodate the bank's needs, make it functional--meet fire and safety standards--and maintain as much, hopefully, as we can to bring this room back as originally conceived," Hamm said.

Also to be restored as much as possible are the proportions of space, and the original windows and trim. Along side many of the large windows on the top two floors were painted wooden panels which revealed, when the paint was loosened, that they were enclosures for the original mahoghany shutters that folded out to cover the windows. Many of them sported their original brass hardware. Leading to some rooms are some of the building's original wood doors, also with old brass doorknobs and baseplates. The doors will be stripped down to their original wood and saved, although they may be used in other rooms than the original ones.

A marble staircase with wrought iron railings and mahoghany bannisters leads from floor to floor. "The ideal thing would be to retain it as is," Hamm says. "If you cannot, you should reuse it someplace else here." That is planned, for instance, for a fireplace that will be moved from the fourth to the fifth floor.

According to NS&T Vice President Susan L. Martin, the bank originally was going to build a 450,000 square foot office building adjacent to the present structure with a developer and rent out some of the space. However, those plans fell through when the developer became worried about the current glut of office space.