ARCHITECT/builder Jack Greenspan asked Marna and Fred Zanoff what rooms in their new house they'd like to have two stories high. The Zanoffs said "All."

It was a tall order - especially since the Zanoffs wanted not only two-story high rooms but two stories of rooms. But Greenspan came through. Every single room on the main floor rises to 18 feet - including the laundry and the three full and two half bathrooms. And there's a full basement, though unfinished, if any more space is needed.

All this for less than $250,000 including the lot, three years ago.

The house gives a rather blank look to the street, rightly turning its best face backward to the rear of the lot and the swimming pool.

Once they'd spent all that money, Marna Zanoff thought she'd take on the decoration of the house herself. The way she did it offers instructive thoughts for other people who want to substitute ideas for cash.

She's added furniture slowly, a pieced at a time - the living room is totally empty, waiting for that white enamel grand piano they hope to buy some day. "We didn't really want a living room," said Zanoff. "But our architect said we'd have to have it for the resale value, and it comes in handy when we have a big cocktail party. It's more space to stand.

Instead of furniture and paintings, she furnished the house with color and design - super graphics she painted herself. All the lighting is built into the sloping celling - Zanoff has an industrial changer pole.

"Those high walls are wonderful, but they need something to keep them from seeming blank," Marna Zanoff said.

So she took brush in hand and proceeded - as a child once put it - "to draw all over the walls." The family room has a huge four-color stripe which swoops through the room, ranging over door and wall alike. In the dining room, a strip on the rug goes on rug goes on up the wall, visually extending the room.

But 11-year-old Cara's room is the last word - the word being Cara, repeated 21 times, each in a different style of lettering.

"It took eight weeks to do," said Zanoff. "And the day I finished, Cara looked thoughtful and said, 'I think I'll change my name to Caroline.'"

The house has some other nice touches. The foyer is floored with ceramic tile. All the windows are set out from the walls to make window seats in some places, plant shelves in others.

The kitchen is white with black glass fronted ovens. There's one of each from a trash compactor to a microwave oven. The most useful thing, according to Zanoff, is the big square counter, three sides with storage, one side cantilevered for a bar. A Jenn-Air grill is built into one side. On another counter is a built-in warmer.

Off the laundry room is a half bath and mud room which also serves Cara and the other daughter, Shari, 9, when they swim. The storage in the house is well thought-out. The Zanoffs are ski enthusiasts, so one whole closet is devoted to ski clothing and equipment. The bedroom hall is screened from the rest of the house by a wide closet which holds the overflow from the bedroom closets. The parents each have a walk-in closet. Their luxurious bath has a mirror, wall-to-wall, over the extra large step-up tub.

Marna Zanoff, a realtor associate with Schick & Pepe of Potomac, also has a good-sized office, just around the corner from the foyer.She sells, among others, houses designed by Greenspan and built by him and his partner Bob Keats of Construction Group, Inc. A house similar to the Zanoff house is up for sale for $327,000. Fred Zanoff manufacturers the One Write Bookkeeping System.

Other houses on the torr belong to Grace and Sumuel Gorlitz, designed by Rick Eckstrom; Karen and George Diamond with works by the late Pietro Lazzari; Richard Waley, an interior designer; and Margarita and Charles Seckinger, designed by Mrs. Seckinger with solar panels. Tickets are $8.50 with the profits going to Congregation Beth El. The houses were selected by architects Juan Gruner and Tom Clark.