The city's Landmarks Preservation Commission held a hearing yesterday on plans to renovate and add a story a rooftop addition to and enlarge a chimney at 141 Fifth Avenue, the very ornate, domed and handsome building on the southeast corner at 21st Street.

The building, which was erected as the Merchants Bank of New York Building in 1897 and designed by Robert Maynicke, was recently acquired by SL Green and Savanna Partners for about $60 million.

SL Green owns the lower two commercial floors and Savanna Partners plans to convert the top ten floors to about 40 condominium apartments.

Cetra/Ruddy Incoroporated is the architect for the conversion and its spokesman said that the Beaux-Arts-style facade of the building would be cleaned and repaired and that a removed balcony on the fifth floor would be replaced and that dormer windows will be restored to the cupola. He said that the domed cupola will be examined to see if it was ever gilded. Rendering at the right indicates present condition in black-and-white and planned restoration of the dome in color.

An existing exposed rooftop watertank will be removed in the plans. Part of the rooftop addition will be for recreational space for the apartments.

Community Board 5 has passed a resolution approving the proposed changes.

Several members of the commission applauded the proposed plans. Roberta Brandes Gratz described the structure as one of the "iconic" buildings of the Flatiron district. A Spokesman for the developer indicated that plans for the restoration of the two-story base of the building were contingent on the expiration of existing commercial leases.

The base was modified somewhat in the 1950s and Savanna's architect indicated that original capitals to the stone pilasters could be replicated.

Jack Taylor of The Drive to Protect the Ladies' Mile testified that "Much as we admire the applicant's largely successful efforts to restrict the visibility from the public way of the proposed roof additions and to make judicious alterations to the building's two-story base, we think that more should be done to comply with the provisions of the Zoning Resolution that call for a program of continuing maintenance that results from the preservation of the building the full restoration of its facade to justify approval of the conversion of this glorious Beaux-Arts store-and-loft structure to largely residential use."

"While some of that 'full restoration' is accounted for magnificently on the dome and in the replicated fifth-floor corner balcony," Mr. Taylor cotinued, "we are especially disappointed?that plans for the ground floor do not include the return of the great rounded corner-bay window so prominent in early photos of the building. This was the era when the perfection of plate glass made possible these vast windows for mercantile display, and they were a hallmark of the Ladies' Mile shopping experience. So, too, was another hallmark of the Ladies' Mile, on its skyline - the ubiquitous water tank, a Manhattan icon now fast disappearing. We do not condone its removal in this application."

The commission indicated it was interested in a "top-to-bottom" restoration and closed the hearing.