FOR YEARS, Washington people, holding their noses on the K street expressway, drove past silos and smokestacks and the sign that said something like, "The objectionable odors you may notice do not originate in this plant."

A flour mill had been on the spot since 1832, a year after the C&O Canal completed its 35-foot fall to the Potomac River. Eight flour mills and four grist mills, run by water power and served by river barges and canals, made Georgetown the center of the U.S. flour mill industry. The last one was the Bomford Mill, sometimes called the Pioneer Mill. Later it became the Wilkins-Rogers Milling Co., makers of Washington Flour and ready-mixes (especially spoon-bread). In 1977, Wilkins-Rogers left, leaving behind two buildings deemed worth saving for both historical and practical reasons.

The 1847 five-story building had thick masonry load-bearing walls, heavy timbermill-type construction and sturdy columns. The 1920 six-story mill building had an exposed concrete frame classically proportioned with column, plinth and entablature. Weissburg Development Corp. hired ICON, the International Consortium of Architects (Peter J. Vercelli as the principal), to come up with a design to incorporate the old buildings into a massive development that would go up and down the hill -- adding something like 250,000 square feet above and below ground to the original buildings.

The almost completed 1000 Potomac St. NW is one of the two first-place award winners in this year's historic preservation program of the Washington Metropolitan Chapter, American Institute of Architects. Awards to the architects, owners and contractors of the first-place awards, six merit awards and two citations will be presented along with the chapter's honor awards for new buildings Tuesday at a dinner at the Cosmos Club, itself a magnificent example of preservation.

ICON made the old buildings into a backdrop for a pedestrian plaza, built a new office building between the two old structures and apartment buildings with neo-flour-mill silos as service towers. ICON reconstructed the flume water raceway, which once drove the water wheel. The public walkways were extended to a 20-foot width. The old Fish Market Square will be renovated at the Flour Mill's expense and maintained by the National Park Service, at the suggestion of ICON.

Century Construction Company of Washington was the contractor.

If preservation means restoration to you, you would hardly recognize the Flour Mill office complex as in the category. But the heavy-wood columns, exposed brick walls, balconies and high ceilings carry with them the amenities of the past. The agreeable contemporary architecture is much more pleasant to look at than the old buildings. And no one has to hold their nose when they go by.

The other first-place award went to 1785 Massachusetts Ave. NW, a more classic preservation project. Yerkes, Pappas and Parker were the architects, with Nicholas A. Pappas as a partner-in-charge for the owner, the National Trust for Historic Preservation.

The Beaux Arts style building originally was six immense luxury apartments, designed by Jules Henri de Sibour, completed in 1917, when people could afford to comfort themselves with marble fireplaces, high ceilings, and servants quarters complete with servants. Andrew Mellon's residency was the building's chief claim to distinction. The story, disputed by some, grew up that Joseph Deveen had once rented the apartment below Mellon's to sell him paintings and to urge the establishment of the National Gallery of Art.

In 1941, the building was taken over for wartime offices. Wartime civilian occupation of buildings is usually as devastating as wartime military occupation of countries.

The baths and kitchen plumbing, the chandeliers, the elaborate cabinets were all ripped out lest they corrupt the war workers. Awkward lights were stuck like stalagmites on the ceilings. Partitions grew like weeds in the middle of the floors. Surface wiring like some noxious vine curled around the walls. Air conditioning units and duct work coiled around the ceilings and burst through the windows. Strangely, but fortunately, much of the complicated plasterwork, mantels and trim remained, though often interrupted by intrusions of the rough occupation.

In 1977, the National Trust bought the National Historic Landmark building to use as its headquarters. Pappas, who served for several years as chairman of the AIA preservation committee, went to work to restore the building as far as possible while adapting it to office use and making it both accessible to the handicapped and reasonably energy-efficient.

Pappas accomplished the remodeling by preserving the class distinctions between the owners' and the servants' areas. In the plain, utilitarian space, he lowered the ceilings so he could run in ducts, wiring and piping. In the principal rooms he kept the old radiators and added individual thermostat controlled valves. For cooling, registers and grilles were carefully integrated with the plaster ornament. Electrical service was wired in with wiremold underneath new trim following the old baseboard designs. wUnfortunately, some new, office-type ceiling lighting, thought to be necessary, was installed in a rectangle.

The existing light shaft was used for mechanical space, an exit stair tucked into the vent shaft. The main elevator still works and a second passenger one was provided by the old service elevator. The gorgeous old wood parquet floors are not hidden beneath carpeting, but they are there when some enlightened owner get around to restoring them.

In any case, though lacking the grandeur of Mellon's magnificent painting collection and the luxurious furnishings of the second decade of the century, at least the building makes a pleasant and appropriate setting as the National Trust goes about saving other buildings across the country.

Charles H. Tompkins Company of Washington will be honored as the contractor.

The AIA merit awards will go to the following six projects.

The neo-classical Holy Trinity Church, 36th and O Street in Georgetown, was a controversial project because radical activist Mitch Synder (with support from members of the Community for Creative Non-Violence) fasted for 12 days in an effort to make the church give the $400,000 allocated to the reconstruction to the poor instead. The church rejected his demand. The planned restoration had been planned because of the deterioration of the building and its non-conformance with fire codes.

Giuliani Associates, the architect, reopened arches on the sides of the sanctuary to expose the original stained-glass windows, and make a baptistry and an altar of repose. New heating, air-conditioning and electrical systems were intergrated into the restoration. To serve new liturgical requirements, some old furnishings were modified. The podium, for instance, became the baptismal font.

Charles Tompkins was also contractor for this project.

Beaux Arts townhouses are today the most popular offices. Too often, the buildings are adapted without too much respect for their past glories. But when J.L. Sibley Jennings of Alexandria and Richard Ridley & Associates of Washington were hired as architects for Losch & DePuy's offices at 1716 New Hampshire Ave.NW, they found the handsome old townhouse could be restored to something like its original glory.

In 1909, architect Clarke Waggaman designed the limestone Louis XVI townhouse for Anne Thorburn Johnson. In the last 30 years, it had served as offices for a succession of tenants.

In the process, the architects say, "neo-Georgian" building parts were substituted for the original doors and millwork. Layers of paint filled in all the delicate mouldings. Bronze radiator paint coated much of the architectural details. Leaks damaged the plaster. The parquet floors were stained, gouged and rotted and finally covered with wall-to-wall carpet, "secured with spikes and masonry nails."

But after the architects went to work, they found the original interior French doors and the hardware, escutcheons and the stairhall chandelier in piles of trash in a coal cellar. Under the gunk, the drawing-room mantel and baseboards turned out to be Sienna marble and much of the cabinetry and stairs was solid American Chestnut.

No general contractor was used, but the craftsmen and shopkeepers who contributed to the restoration included: painting, glazing, graining, marbling and, gold leafing, Christopher C. Stapko, Mclean; wood flooring and cabinets, Randall Edwards, Silver Spring; stone mason and pointing, Carlo Donofria and Frank Cangelosi of Clinton; plaster moulding, Bob Giannetti, Brentwood, Md.; wooddworking and moulding, Arlington Woodwork of McLean; metal plating and polishing, Alexandria Metal Finishers, Inc.; hardware, Union Hardware; electrical R. Archie Bugess, Inc., of Washington; plumbing and heating, Samuel C. Boyd.

The Sheraton Carlton Hotel at 923 Sixteenth St. NW, under the direction of Rose Narva, then general manager, and architect Mihran Mesrobian, was restored to some of its 1926 Beaux Arts exuberance with help form Hudson-Shatz and Corning Construction. The first floor lobbies and dining rooms regained their original elaborate ceilings and the guest rooms were redecorated. The building was also air-conditioned and "environmentally sealed." All, according to Narva, while trying to "keep our goal of 'total restoration' from being undercut by the ever worrisom budget analysts at corporate headquarters."

Narva has since taken on the Jefferson Hotel at 1600 Sixteenth St. NW.

At Emmitsburg, Md., St. Joseph's provincial house, the mid-18th-century home of Elizabeth Ann Seton, the first American-born saint, was moved a half mile when the campus of the Daughters of Charity was sold. Faulkner, Fryer & Vanderpool were chosen as architects with Vicente S. Cordero as partner in charge. James G. Davis Construction Corp. was contractor and William B. Patram moved it.

The inside and outside plaster over the original stone and the 19th-century woodwork was all replaced. The building now serves as a shrine to Mother Seton.

A development at 1001 Pennsylvania Ave. as a commercial center with restaurant, shops and offices, not yet executed, is being designed by Hartman -- Cox/Smith, Segreti Tepper Associated Architects. The building is expected to be completed in 1983 by George Hyman Construction Co. Owners are 1001 Associates.

The site takes up the whole block between Pennsylvania Avenue and E Street, 10th and 11th Streets. The U.S. Storage Building and Dart Drug facades on the site will be preserved. The facades of buildings at 421, 423 and 425 will be removed and given to the Pennsylvania Avenue Development Corp. for possible use elsewhere.

Kennersley, near Church Hill, in Queen Anne's County, Maryland, is a magnificent five-part historic house built somewhere between 1740 and 1770. Warren Cox of Hartman-Cox architects is restoring the building himself for his wife, Claire and their family.

Two citations were made by the AIA chapter.

An informal living area opening up for light and garden views, an addition to a private residence in Chevy Chase, was designed by Hugh Newell Jacobson for Mr. and Mrs. John S. Kingdon. Jack Fisher was the contractor.

An abondoned 1909 streetcar substation and boiler plant on Baltimore's Inner Harbor waterfront was remodeled to a design by Anderson Notter Finegold Inc. of Washington and Boston into The Chart House restaurant. Contractor was Jolly Co. of Baltimore.

What is preservation? You certainly can't tell from the awards given this year, locally and nationally.

I propose in the first place that we only preserve buildings that still have life and beauty. I see no reason to preserve unusable timbers or foundation stones on a site if they tell us nothing about the wawy people built or the way they lived. Move them to the Smithsonian and put up a plaque on the spot.

Restoration is a simple concept: You choose an old building that is better than anything we can build today and you put it back the way you think it was, as best you can.

Some of the awards to buildings here clearly qualified: the National Trust, Kennersley, the Sheraton-Carlton exterior and public rooms, the Holy Trinity Church and the Losch & Depuy law offices. Even the Old Stone House, though I'd like to see the stone instead of the stucco, no matter how impractical.

The other two categories, "preservation through extended use" and "preservation through new structures," seem to me a license to kill.

Tearing down buildings and carrying the facades off someplace else to be propped up, blowing up silos and building new ones, adding on modern additions to 1930s neo-Georgian structures -- tearing down everything and putting something else on the site -- call these preservation?

I feel that the new Flour Mill residences and offices are a great improvement on the old industrial buildings. If I lived in the Kingdon residence, I would certainly want to have a Jacobsen addition. I much prefer to eat lunch at the Chart House than in the car barn (though I might prefer to take a trolley from the barn).

But I don't think we should call them preservation. What about calling them architecture?