A city rental renovation

Stewart Roy Skolnick, a young New York architect who finished graduate studies at Cornell University only last December, considers himself fortunate to have found a walk-up railroad flat in East Greenwich Village for less than $400 a month.

The apartment was, at first glance, three tiny rooms with crumbling plaster, a bathtub in the entry, and two windows that looked out over an old church and a vest-pocket park.

Since the apartment had to serve as his office as well as his home, Mr. Skolnick rolled up his sleeves and set about creating his own environment in the erstwhile tenement. He got his landlord's permission to remove all the room partitions, take out the bathtub, enclose a stall shower, and put in the barest rudiments of a kitchen - a small sink, range, and refrigerator tucked at the entrance end. He enclosed the shower and toilet with a shoji screen arrangement, covered the walls with sheetrock, and then painted the whole place a sort of oyster white.

The white paint, while currently not all that fashionable, serves, he says, to make a very small space seem larger and to make an unairconditioned area seem cooler. It also provides a neutral and restful backdrop against which he shows his drawings and plans to clients. He kept the modest mantel of the long-closed fireplace as a reminder of what the house might have been in the past. On the mantel he keeps white pinup boards, on which he tacks an endlessly changing stream of drawings that he studies and contemplates as he works at his drafting board across the room.

Basic to the room's uncluttered look and design is the all-in-one living center (the architect calls it a ''monolith''), which includes a sofa bed for sleeping and seating, storage, an office area, desk and drafting board, and a rounded end for conferences or dining. Two Le Corbusier chairs in chrome and black leather pull up to it. The architect and a friend constructed the monolith from $800 worth of supplies; he estimates it would have cost over $5,000 to have had it custom built. Its exterior is a white plastic laminate, and the sofa bed is covered with white leather. ''Basically everything I own,'' he explains, ''is in the center of the space. These are my objects, and these are my tools.''

There is no other furniture in the room, and the walls are left relatively clear. A white vinyl shade pulls over any architectural drawings placed on the wall for a client's inspection. A framed architectural rendering of the room hangs between the bare windows, whose expanse is broken only by the black iron security grids in shoji grid design. A chrome cylinder lighting fixture 15 feet long hangs from the ceiling and lights the entire space.

Mr. Skolnick considers it important to keep fresh flowers in a cylindrical crystal vase at the end of the monolith, because ''I have no green thumb and can't raise foliage plants. So every Monday morning I buy flowers, and they last a week.''

The architect's bow to classicism is indicated by the fragment of an oak Ionic-column capital (salvaged from a demolished hotel at Times Square) that decorates the wall of the entryway and by a Victorian black marble mantel clock. It doesn't work, but it resembles a little Greek temple; it was bought to be decorative, not functional. The Bauhaus architect's lamp - made in Germany, but purchased in an antique store in New York - is another reference to the past. The designer says of the three artifacts that dominate the room:

''Three is enough. When one displays fewer things, one appreciates them more.''

This is not to say that Mr. Skolnick is not a romantic of sorts. He terms the feeling of his flat ''surreal,'' and he likens the old ethnic neighborhood around him to Paris in the 1920s, when it was full of struggling artists, small cafes, and ideas running rampant. He finds the ambiance of the lower East Side creative and stimulating.

After studying architecture for eight years in this country and abroad, he finds New York City the best place in the world to study urban and architectural design. ''I think of this whole city as a museum, and I love being here.''

The architect describes his one-man business, which he opened in March 1982, as ''a firm involved in contract and residential projects that seeks a poetic quality in its art.''

He admits that one has to be pretty secure to tackle a rental renovation such as the one he has just completed. It did, however, just win second prize for him in the 1982 American Society of Interior Designers Barcalounger design competition. A jury of top-flight professionals was particularly impressed with the way he so creatively planned the space in a very small living-working apartment.