On that memorable last day of shooting in December 1987, when the renovation was supposedly complete and ready for inspection, Bob Vila, then host of the popular PBS series This Old House, smiled into the camera and proclaimed Weatherbee House "beautiful." Bill and Cynthia Dromgoole, the owners of the 200-year-old farmhouse outside Boston, thought somebody had a screw loose. The home might be telegenic, but rain leaked in, the stove pilots didn't work, the heating system was incomplete, and the lamps in one bedroom were plugged into an extension cord from the basement.

Truth was, Russell Morash, the creator, director and executive producer of This Old House, had left more than a bedroom in the dark. The price of the renovation, first estimated on the air at $100,000 and revised weeks later to more than $200,000, still represented only the expense paid by the home owners. The true cost was actually $440,000—counting the $250,000 in free supplies contributed by commercial suppliers. Says Vila: "We would gloss over the cost of all the donated materials so that, in fact, the half million dollars that was spent on a project would appear as being much less."

When the Dromgooles went to the press with details of their renovation, one Old House staffer called it Russ's Waterloo. Not quite. Russell Morash, 54, came to public television straight out of Boston University in 1957 and over the years created a how-to empire on the Public Broadcasting Service: Julia Child's French Chef in 1963, The Victory Garden in 1975 and The New Yankee Workshop in 1989. But the biggest bouquet of all—the one Morash himself called "the Wheel of Fortune of public TV"—was This Old House, a do-it-yourself opera for home owners. Now ending its 11th season, This Old House has won five Emmys and draws 12 million viewers a week.

Still, some of the show's own foundations have now begun looking shaky to critics of its ethics. The most ominous charge: The lure of free materials from manufacturers has subtly altered its how-to-build format into one of how to buy, giving the appearance, at least, that the spirit of commercial-free broadcasting is being compromised.

By the time the army of carpenters showed up at the Dromgoole house in July 1987, the program staff no longer demonstrated how to repair an old sink at minimum cost. Instead, they laid in state-of-the-art fixtures and brought in a decorating team from Country Home magazine. To "pay" for the donated products, brand names were dutifully touted and lingered on by cameras until Morash calculated that he had settled the account. His self-admitted call to the cameramen—"Hey, have we paid these guys off yet?"—became a commercial tocsin to the Old House crew. "This isn't cutting-edge technology being showcased," grouses one employee of WGBH-TV, the Boston flagship station that produces the show. "It's cutting-edge advertising."

Morash, for his part, denies pushing product names in front of the cameras but says the show's annual budget—about $1 million—makes accepting those products a necessity. And if a company is generous enough to supply wood or wiring, "we have a responsibility to show it or mention it. I think it's only fair."

Certainly the arrangement has pleased the home-products industry. "It's been pretty tremendous for us," says Glenn Eige of the Hurd Millwork Co., a Wisconsin-based firm. "We're a relatively small company compared with some of the major window companies. This enables us to reach people we otherwise wouldn't have. We couldn't afford this kind of network prime-time advertising." "We do it for the exposure," echoes Dick Cordeiro, a general sales manager for the floor-covering division of Eastco. "When they endorse a product or show a product like that, consumers shop for it. I couldn't buy the national TV advertising for what it cost me for the tile in a foyer."

Despite the candor of his contributors, Morash insists that the tenor of This Old House remains unchanged. "I never saw it as a how-to show," he says. "We simply explain, maybe illuminate a little bit. Maybe we throw a little light on the subject of what it's like to go through some of these building processes. That was the premise originally, and it still is."

Trouble is, that's not the way many fans think of the show. The style has always been informal and folksy, implying a practical approach to the question of shelter. The host for its first decade, Bob Vila, now 43, seemed to engender this self-reliant, denim strength from the start. Until his Newton, Mass., Victorian home was picked to be featured on the pilot, Vila had been a small-scale developer and restorer in the Boston area. Hired as host for a modest $250 per episode, Vila says that Morash dangled potential product endorsements, citing the prize example of Julia Child, who took home extra income from videos, books and outside product plugs. According to Vila, Morash told him to follow the same recipe. And so Vila did, reaching a point where he earned $250,000 annually just from endorsements. Vila insists the practice was known to all, and WGBH station manager David Liroff concurs. "All of Bob's commercial activities were done with my approval," he admits.

Still, a conflict arose last spring, says Vila, when he began doing outside endorsements for Rickel Home Centers. Because of potential competition with local underwriters of This Old House, station officials asked Vila to drop Rickel. When he refused, Morash dropped him. (He now hosts a syndicated Mr. Fix-it show titled Home Again with Bob Vila and continues his endorsements, including ads for Time-Life home repair books).

Last October, the 11th year of This Old House began with a new host, Steve Thomas, 37. Unlike Vila, Thomas will not be permitted any outside product plugs. Moreover, needless mention of manufacturers' names will be avoided, says station manager Liroff, and the old practice of citing costs but failing to factor in freebie goods will be discontinued. Now all costs are made "obvious on the air," says Liroff. "We're doing what we should have been doing all along."

Perhaps. But what remains even now is a decidedly fuzzy line separating commerce from the noncommercial. Nowhere is that blurring more obvious than in the life of Morash himself. The Lexington, Mass., home he shares with Marian, his wife of 32 years, is a renovated 19th-century farmhouse. In back stretches a well-tended landscape that viewers might recognize as the TV setting for The Victory Garden series. Down a path stands a large barn that houses The New Yankee Workshop. Marian Morash prepares family meals in the well-appointed kitchen that is also the set for her "Chef Marian" segments on The Victory Garden. For Morash, going to work often means little more than rolling out of bed and strolling across his own property.

"What you see here is the product of almost 30 years of one job well done," says the how-to maestro proudly. It is, to be sure, a world in which he feels cozily at home in more ways than one. For the viewers of This Old House, however, perhaps a window is opening at last to let in some light.

—Ken Gross, Sue Avery Brown in Lexington