Suburban make-over adds elegance to 'tired looking' living space

Transforming the living room and dining room of a 1960s split-level ranch-style house into a single, elegant space was the assignment given to New York interior designer Lisa Rose.

The house, in a Long Island suburb of Manhattan, is an ordinary builder's kind of house, without great architectural detail outside or inside.

But the family living in the house has been slowly chipping away at redecoration, doing a room or two each year.

This past year, with their two children grown and almost out of the nest, they decided it was time to redo their well-used and somewhat tired-looking living room and dining room. They sought the assistance of Miss Rose and asked her help in giving them a new look and a setting more in keeping with their current living and entertaining needs.

The couple indicated that they wanted ''something with a little glamour and a little dramatic impact, but also a room that was completely functional, peaceful , and equipped for easy living.''

After considering several options, the couple decided to go with the idea of removing the dividing wall and converting the two rooms into one big 26-by-21 -foot space that they would use for living and entertaining.

They did not mind giving up their separate dining room, the husband and wife say, because they had used it only occasionally at holiday times and when guests came to dinner. The family usually ate in the small dining nook off the kitchen, so the dining room was essentially just walk-through space.

Today this new extended room is spacious enough to provide the owners with the freedom to entertain either informally or elegantly.

Two identical glass-top tables, each 52 inches in diameter, replaced the large rectangular dining table. Both the couple and Miss Rose agreed that conversation flowed more easily when guests were cozily seated at a round table, and that two smaller tables made for a nicer feeling than one large, long table.

Each round table seats six or eight comfortably. With the addition of extra fold-over circular board tops, made by a neighborhood carpenter, each table can seat 10 guests. When the party is small and only six or eight places are required, the second round table is used for service or for buffet serving. Between dinner parties, the tables are used for informal family dining or for plants or decorative objects.

Following are some of the methods Miss Rose - whose firm is Aubergine Interiors Ltd. - employed to complete the face-lifting conversion of the room.

* The color scheme chosen for the expanded room was a rich terra cotta, pale peach, and sandstone.T

* The large 60-by-42-inch coffee table and the upholstered seating pieces around it were placed in a diagonal arrangement to give the room a new focal center and to give those seated a different vantage point from which to view the room.

* Thin-slatted vertical Levolor blinds were hung from ceiling to floor to give a smoothing uniformity to walls with odd-size windows and to give privacy and controlled light to the window wall. Such a window treatment, the designer explains, not only camouflages the various-size windows but adds a crisp, clear, architectural look to the room as well.

* Canvas, hand-painted in textured striations of terra cotta, was applied to the walls to give a rich, luxurious look. Such walls are more expensive ''up front,'' says Miss Rose, but they last years longer than an ordinary paint job.

* Wall-to-wall carpeting, in a rosy terra-cotta tone, was chosen to draw the room together.

* Spotlights are used to highlight art work and plants. General illumination comes from recessed ceiling lights and from one reading lamp and one handsome table lamp.

* The small upright piano that had been in the family for years was refinished in a light, peachy color that blended it into the background. The piano bench was upholstered with a beautiful figured silk so it could be pulled into the conversational group for extra seating, if needed, or double as an ottoman.

* A custom-built cabinet extends for 11 feet and is 20 inches deep, centralizing items formerly scattered throughout the house. It fits under the windows and is finished with a terra-cotta lacquer.