The asking price on the house may top $1 million, but if there aren't enough nails on the deck joist hangers or felt paper under the roof shingles, you can bet Donald Cronig is going to make a stink about it.

In the frenzied world known as the Vineyard real estate market where a dilapidated ranch house now fetches upwards of a half-million dollars, Mr. Cronig plays the dispassionate role, free of emotion, hype and sales pitches.

He is the home inspector, one of only two licensed inspectors on the Island and the guy some prospective homebuyers call for a dose of truth before they plunk down all their cash for a house on Martha's Vineyard.

His business is called Beacon Home Inspections, and he's been climbing up ladders, poking his head into crawl spaces and popping open electrical panel boxes on the Island since 1981. In more than two decades, he has earned himself a tough-guy reputation, especially among the real estate sales force.

"There are still a lot of brokers on the Island who call him the deal killer," says John Best, a broker in Vineyard Haven. "But he's the best around. He has a credibility."

Mr. Cronig, who is 57 years old, is unapologetic.

"I make sure people get their money's worth," he says. "I'm not there to be an obstructionist."

But in the dance between buyers and sellers where real estate brokers represent the sellers, Mr. Cronig is more often than not the buyer's only advocate.

"Isn't that sad?" he says.

Well, maybe it's not that sad, considering the zeal with which he pursues the job. His pet peeve is shoddy workmanship, and his fearlessness in pointing it out in the course of a 15-page report often lands this home inspector in some hot water.

Those nails missing from the joist hangers? That house was built by what Mr. Cronig described as a reputable builder on the Island. And that wasn't the only problem. Porch posts were not seated fully on the footings.

"The builder was flipping out about it," says Mr. Cronig, whose expression is at once quizzical and bemused. "Some folks are mad about this process."

A lot of money is on the line, but the flip side is even more important: safety.

"What if they had a party on that deck and it fell over?" he asks.

Buyers, he says, are often more worried about landscaping and building retaining walls than they are about fire prevention and smoke detectors. "People want the glitz," he says. "I'm more of a nuts and bolts kind of guy."

Indeed, Mr. Cronig possesses an everyman quality. Plainspoken and gregarious, he tools around the Island in his 1997 Ford Escort wagon and seems perfectly content in his role as the defender of consumers tossed into the shark-infested sea of sales agents and building contractors.

"I'm not anti-contractor. Have I said that a few times? There's a lot of great contracting going on around here," he says.

But in Mr. Cronig's eyes, it's all about zooming in for a closer look and taking note of things like roof shingles that weren't nailed down.

Sellers show him building permits to prove that work has been done, but did anyone ever come back and inspect the work after it was completed, he asks.

"If we have a big hurricane, that's when this is going to show," he says.

Other areas of concern for Mr. Cronig are radon, mold and septic tanks. He's found some hot spots on the Island for radon, a naturally occurring uranium gas. As for mold, the Vineyard is a damp place, and he highly recommends that homeowners buy dehumidifiers.

Septic systems? Mr. Cronig says that real estate brokers are annoyed when he goes peering into the septic tanks. "If the septic tank is full, why should I buy someone else's effluent?" he says.

Mr. Cronig charges at least $400 for an inspection and typewritten report, which can run from 13 to 20 pages in length. The report frequently becomes a bargaining chip, a punch-list for repairs or even an exit strategy.

The home inspector cautions clients not to let the seller take care of fix-it jobs.

"The seller will not care about the quality of the work," he says. "You're better off to take the time to find out who's good on the Vineyard and hire them. There are great contractors out there, why hire the schlockers?"

His report can also be a prospective buyer's sole insurance to be able to back out of a contract.

"Being called a deal killer? Sometimes I find out people didn't buy a house but I can't help that," he says.

Before his life as a home inspector, Mr. Cronig worked as a carpenter and as a chimney sweep. "I got real curious about what was wrong with things," he says

In the ensuing years plying this sideline of the real estate market, he has watched the changes, and especially the trajectory of the prices. "If it hasn't burned down, you can sell it. Unless it's polluted by nuclear water, you've got something people can use," he says. "Everything is being utilized because of the great demand."

While there's been talk of a bubble, Mr. Cronig does not portend any significant crashing of Island real estate values. But he does promise to keep being vigilant.

A cousin of the actor and television producer Jeffrey Kramer, Mr. Cronig displays some of his own theatrical talent when he squints one eye, turns down the corners of his mouth and declares - in his best western accent - that there's no stopping this home inspector: "If you're a Realtor, you're going to have to shoot my tires out first."