The Washington Project for the Arts yesterday unveiled its latest art commission: a studio apartment for visiting artists, performers and writers, refashioned from an unkempt second-story restroom for employes of the F.W. Grand five-and-dime that used to occupy the WPA building downtown.

The beautiful room, coproduced by California artists David Ireland and Robert Wilhite at a cost of about $50,000 (half of which was provided by a matching grant from the National Endowment for the Arts), is an eerie admixture of architecture and art, and it moodily transcends conventional distinctions between the disciplines.

It is functional, in its way. Measuring about 20-by-20 feet, the room contains the (very) basic necessities: a daybed (designed and constructed by Wilhite) inched into a nook underneath an angled stairwell ceiling, a triangular table and six side chairs (also Wilhite's), a compact store-bought kitchen unit (containing stove, sink and refrigerator), some built-in shelves, a tiny doorless toilet-shower room and various lighting fixtures, including a standing lamp of Wilhite's design, two shadeless chrome-tipped incandescent light bulbs hanging from the ceiling, a circular fluorescent wall fixture and two exposed fluorescent tubes attached to the ceiling.

But the mind-teasing lessons of the room are not to be found in its bare-bones practicality. In the exquisite ordinariness of its materials and the ways they have been treated, in the calculated funkiness of its look, in the sophisticated rawness of its feel, this is altogether an up-to-date, ironical place.

Ireland and Wilhite, from Northern and Southern California, respectively, share art school (rather than architecture school) backgrounds, and the work of each in recent years has tended to occupy border zones. Ireland's most publicized work so far has been his own home in San Francisco's Mission district, an unexceptional Victorian-era house on the outside that is, on the inside, an extraordinary environment in which art is not something added -- the walls and spaces are the art. Wilhite's work has evolved from sound and performance pieces for which he constructed an odd assortment of musical instruments (some hilariously nonfunctional) to making pieces of furniture that, besides being useful and painstakingly crafted, are very much about the processes of making and perceiving art.

Invited to Washington to collaborate on the visiting artist's apartment by WPA director Jock Reynolds, the pair initially thought of the project in more experimental, conceptual terms. Ireland, for instance, began with the idea of a building a little log-cabin-like house within the room. Gradually, however, practical considerations (that is to say the demands of architecture) took hold, and their collaboration was divided on more or less conventional lines. Wilhite supplied the furniture and many other accoutrements, and Ireland took charge of the basic spaces.

The results are very un-Washington-like and entirely unusual. Consider, for example, some of the materials and their uses: galvanized steel sheets employed on walls as if they were wallpaper, corrugated metal panels of varying heights deployed as curvilinear space dividers, waterproof sheets of dry wall (with an odd, translucent green color) nailed to the ceiling, plain plywood planks (given a semi-transparent coat of gray paint) screwed to the floor. Everything that is usually covered up is left exposed: nut-head screws, Phillips-head screws, flat-head nails, light bulbs and tubes, metal corner fixtures, unsanded drywall "mud."

Ireland's four main tactics, vis-a -vis the ordinary materials, forces us to see them freshly: He simply left them alone (most of the dry wall is not taped), or he exposed them as if he were an archeologist (partially sanding down an existing wood door to reveal its multicolored layers of paint, and allowing the original plaster and wood to show through in spots), or he used them in unusual ways (we associate corrugated panels with sheds in the countryside, not urban apartment walls), or he subtly altered them (scratching away at the drywall panels before applying a coat of polyurethane varnish).

Clearly, this is the esthetic of the ordinary and then some. The net effect is invigorating not because of architectural innovation, although the floor plan is ingenious enough, but because the parts have been assembled under the control of an artist's eye, and this eye seems responsive, above all, to the transformative powers of light. During the day the place is a subtle, enchanting domain of colors and textures that justify its poetic title -- "The Jade Garden" -- while at night, under the glare of artificial light, the metal and varnished surfaces take on an eerie, edgy glow.

In this context Wilhite's furniture, although beautifully conceived and made, seems almost too pristine, sharing none of the crazy grace of the space. On its own, the massive triangular table, all black, is an impressive object, light in feeling despite its obvious solidity. The side chairs, delicate and pure, contribute to this effect. Perhaps they will begin to pick up some of the mystery of the place as the room's occupants pass through and begin to leave their marks. ("It's about time to round up a cat," Ireland observed.)

The WPA is looking good all over. The bookstore has recently been refurbished and expanded, and the second-floor galleries and the ground-floor gallery-performance space have been spruced up at minimal cost and major effort by WPA volunteers and staff. Reynolds, ever mindful of the institution's shaky year-to-year lease in the fast-developing Seventh Street corridor, confessed his strategy "is just to put so much good stuff in here that the need for the WPA presence downtown will be undeniable."

Local benefactors who helped support the apartment project (and thus provided the match for the NEA grant) were Florence and Marvin Gerstin, Peter and Elizabeth Carley and Robert Lehrman, with Uzzolo's, Bloomingdale's, the Lenkin Co., Mary Pettus Associates and the Capital Hilton contributing materials and services. Sculptor Jerry Montieth assisted in the construction.

Under the WPA's new "International Artist-in-Residence" program, Ulises Carrion, a Mexican-born poet, curator and critic now working in Holland, will be the first person to live in the apartment. But he won't arrive until early next month, and between now and then the room will be open to the public. The WPA, located at 404 Seventh St. NW, is open from 11 a.m. to 5 p.m., Tuesday through Saturday.