The new ornamentalism

In architecture the shift of allegiance is plain: the doctrine that ''austerity is destiny'' has succumbed to the notion that ornament is essential. Somewhere in the process of learning to love old buildings and unlove their boxy International Style heirs, we have adopted a new slogan: Trim that facade!

''The new decorativeness in architecture and design'' is the way authors Robert Jensen and Patricia Conway subtitle the phenomena in their new book, ''Ornamentalism'' (New York: Van Nostrand Reinhold. $40).

From the start they dismiss the 1908 declaration of Austrian architect Adolf Loos that ''the evolution of culture is synonymous with the removal of ornament from utilitarian objects.'' The code of the modern movement that ''less is more'' is rebutted by Robert Venturi's postmodernist ''less is a bore.''

The consensus is clear, then, and on at least one level, the eye weary of the modern idiom - the rigid right angle, the black and white and gray interior, the cities where sleek high-rises flash their blank faces against the carved context of the past - delights in the embellishments summarized here in the sheafs of carved columns, the cornices with elaborate moldings, the tiled floors, stained glass; the zany versions of the 1920s bull-market Georgian (the pre-depression era's Colonialism), trompe d'oeil murals, ballrooms, and their translation onto city streets in, say, Charles Moore's New Orleans Order of the Deli.

Quickly, however, questions follow the jumble of visual stimulators. The wide range of offerings, from patterned waves on the walls of the Americana Hotel Ballroom in Fort Worth, Texas, to the butterfly chair in a Chicago gallery or the classical facades of the 322-unit ''social housing complex'' at St. Quentin-en-Yvelines, outside Paris, boggles the mind.

Does the stylistic display go more than skin deep to serve the emotional, functional, spatial needs of the inhabitants, one wonders; will such buildings really work better? For the few? The many?

For openers, it is ironic that this new architecture of nonausterity arrives in a period of hardship. The heralds of ornamentalism and classical appliques cry out in an era when we cannot roof the middle class, never mind the shelterless.

Then, too, even if we forget that these let-'em-eat-cake concoctions emerge in an era of breadline architecture, how do we find the craftsmanship for their embellishment?

Robert A.M. Stern's Llwellyn, N.J., poolhouse addition, the first entry in ''Ornamentalism,'' is a case in point. However smashingly surrealistic this Roman bath - all Samuel Goldwyn steps, Egyptian columns and ziggurat ceiling, silver palm tree and tiled walls - there are problems. The walls have settled and cracks appear.

The Stern firm calls these ''routine construction difficulties.'' And so they are. But in an era when achieving ''routine'' craftsmanship is so excruciating, where will we find the heroic labors for post-modernist modes?

Whether it's the paint job in restoring Worcester's Mechanics Hall (18 coats, one hears), or the archaeological search for the correct column, it is daunting. Read the ''Historical Preservation'' prescription for Seattle's Four Seasons Hotel:

''Brass hardware from 5,000 windows was painstakingly cleaned. Two-story tall Palladian windows in the main dining room that had been blacked out during World War II were uncovered and restored. Hand-sewn Irish carpeting was laid. The two-story lobby was enriched with 11 varieties of Italian marble. Hundreds of dented and tarnished champagne buckets and candelabra were reshaped and refinished. Ornate plaster scrollwork was touched up or carefully copied from originals. The dirty sandstone facade was restored to its original brown tone.''

The Stern firm and others find some improvement in the crafts. Although real-estate owners have recently stripped the carved masonry from old Manhattan buildings to ''honor'' new safety codes, the mason's art has been revived by building the stone structures of postmodernism. (New York masons work stone ''as well as they did at the turn of the century,'' Stern associate Roger Seifert reports. Brooklyn and Pittsburgh factories turn out classical columns for the new aesthetic.

To execute the detail of their postmodernist or classical houses, the Stern firm has been able to employ boat builders in Martha's Vineyard, cabinetmakers in New York, enduring Yankees and Serbo-Croatians. Another firm, Venturi, Rauch, and Scott Brown, even found carpenters to build a new gingerbread house in Connecticut.

And yet. . . .

Just after the first of this year, Henry La Farge, grandson of the great stained-glass maker John La Farge, stood before an audience at the 75-year-old Rambusch Glassworks on West 13th Street in New York to display slides of the legacy of this most lustrous of all the building arts. There was the transom glass toned to look like marble for the Vanderbilt mansion, the tinted hollyhocks for palatial quarters in Baltimore, three windows for railroad man James J. Hill, a peacock for the Renwick mansion, and so on.

For all their magnificence, these works could not deny their source in the oppressive nascent capitalism of the 19th century: A memorial was made for a bridge builder who ''died of grief'' when the bridge he built collapsed. A stained-glass portrait presented Oakes Ames, who was censored by Congress for the scandalous construction of the Union Pacific, as the seated figure of Wisdom.

There are uneasy parallels when postmodernists adorn palaces in a period of the poorhouse.

For all the criticism directed to the barren International Style, its Bauhaus originators did possess a social concern - a concern with dying craftsmanship which could be restored through the machine, and hence diffused through society, but also a concern with larger issues. The movement was flawed. It failed. But mass housing, for one progressive segment, was high on the agenda.

The International Style was, above all, based on ''an aesthetic fury,'' historian-critic Vincent Scully told an audience at the ''Speaking a New Classicism'' show in Washington (National Museum of American Art through March 28); ''an aesthetic frenzy.'' Yes, but a human grounding, too. Unlike the postmodern formalists, the early modernist aims seemed more intrinsic than ornamental.

Without exhausting oneself in the futile task of redressing all the wrongs of society through architecture, then, one can wonder whether it might not be better to try to maintain, say, La Farge's superb and endangered heritage than to churn out new heirs.

And, if wishes were choices, wouldn't the world benefit as much with, say, 25 feet of chair rail, seven squares of quarry tile, or even for that matter, two gallons of paint to cover the bedroom walls of a public housing project as with books showing the photogenic but stage-set forms of this new movement.