Tim Larsen for The New York Times

A worker plastered a wall and ceiling at a Hovnanian Enterprises home in the Estates at Oakwoode in Old Bridge, N.J., yesterday.

THE housing industry — which largely carried the American economy through the tribulations of the 2000 stock-market crash, a recession and climbing oil prices — has lost its vigor in recent months and now has begun to bog down the broader economy, which slowed to a modest 2.5 percent growth rate this spring.

That was a sharp comedown from the 5.6 percent growth rate of the first quarter, the Commerce Department reported yesterday, caused in part by the third consecutive quarterly decline in spending on houses and apartment buildings, after several years of rapid growth. “It hasn’t slowed down a little bit — it has slowed down a lot,” said Doug McCraw, a developer who has scrapped his plans for a 205-unit condominium tower in a neighborhood just north of downtown Fort Lauderdale, Fla. “Anybody who did not have a shovel in the dirt has chosen to wait till the market settles.”

The housing slowdown is perhaps the clearest effect of the Federal Reserve’s two-year campaign of raising interest rates in a bid to tap the brakes on the economy and reduce inflation. That campaign has been largely successful, with the decline happening gradually while other parts of the economy, mainly the corporate sector, pick up much of the slack.

“Housing is going from being far and away the most important contributor to growth to being a measurable drag, and it’s happening gracefully so far,” said Mark Zandi, chief economist of Moody’s Economy.com, a research company. “But there’s now a growing and measurable risk that things don’t go according to plan.”

The biggest risk, economists say, is that the optimism that fed the real-estate boom will reverse dramatically. The number of homes for sale has surged in recent months, particularly in once-hot markets, like the Northeast, Florida, California and parts of the Southwest. As builders delay land acquisition and construction it could reduce employment and spending in the coming months.

More broadly, just as rising housing prices during the boom added to Americans’ sense of wealth and well-being — encouraging them to spend more on a variety of goods and services — the reverse could dampen sentiment and lead consumers to pull back on their purchases.

While the fate of housing prices has received far more attention recently than real estate’s role as an engine of job growth, the sector has also become one of the country’s most important industries. Residential construction and all the activity that swirls around it — mortgage lending, renovations and the like — account for roughly 16 percent of the economy, making it the largest single sector, slightly bigger than health care.

For much of the last five years, housing — along with health care — was also one of the only reliable generators of jobs. From the start of 2001, when the Fed began cutting its benchmark rate to steady a faltering economy, until early last year, the housing sector added 1.1 million jobs.

The rest of economy lost 1.2 million jobs over the same period, according to an analysis by Moody’s Economy.com. Housing continued its rapid growth last year, and other industries began hiring in far greater numbers than they had been, creating the healthiest national job market since 2000. In the last few months, though, three pillars of the housing sector — homebuilders, mortgage lenders and real-estate agencies — have stopped adding to their payrolls, and overall job growth in housing has begun to slow.

In South Florida and Las Vegas, where contractors until recently complained that they could not find enough workers to begin work on many projects, developers are scrubbing plans for new condominiums because they cannot sell enough units to get construction financing.

Mr. McCraw, the developer in Fort Lauderdale, said slowing condo sales and a 35 percent jump in the cost of construction materials like steel, copper and concrete convinced him to shelve his project. He is now considering building office space, where demand remains strong, or simply waiting for two years.

In Las Vegas, cranes are still busily at work on new casino projects but dozens of gleaming condominium towers that were slated to sprout up a few miles from the Strip are not likely to be joining the city’s neon-bedecked skyline soon. John Restrepo, a real estate consultant in the city, estimates that only about 7 percent of the 60,000 condominium units that were announced and under construction as of the first quarter of the year are actually being built today 

Among the high-profile projects that were scrapped is Las Ramblas, an 11-building, $3 billion condominium and hotel complex being developed by the Related Companies and Centra Properties and had investors like the actor George Clooney.

“The period of irrational exuberance we saw in ’04 and ’05 and the gold rush fever has gone away,” Mr. Restrepo said.

The Commerce Department said yesterday that housing investment fell at an annual rate of 6.3 percent last quarter, after dropping less than 1 percent in each of the two previous quarters. It grew at roughly 9 percent a year during the previous three years.

Still, building activity for single-family homes, condos, hotels and casinos in Las Vegas is vibrant enough that construction workers are not struggling to find work, said George Vaughn, a business manager for a local of the Laborer’s International Union of North America, which represents almost 5,000 workers in Las Vegas. “The boom is still on,” he said.

The situation is somewhat different elsewhere. An official at the International Union of Bricklayers and Allied Craftworkers said housing work was more difficult to find, but most of its members had been able to find work on commercial building sites.

“If something were to happen with both markets, that would affect us — and everybody for that matter,” said Robert A. Fozio, director of the union’s Northern Ohio district.

On average, real-estate jobs pay somewhat less — about 7 percent less a year on average — than those in other parts of the economy. But real estate has also been one of the only industries creating good jobs for workers without college degrees in recent years, especially in construction and contracting work.

At Hovnanian Enterprises, one of the nation’s largest homebuilders, executives are renegotiating the company’s options to purchase land for future developments, in an effort to delay some transactions and reduce the purchase price on other parcels of land. In April, it forfeited $5.6 million in deposits on property near West Palm Beach, Fla., and Minneapolis, because it was not ready to build in the area. “It doesn’t make sense to own the land and have it sit there,” said J. Larry Sorsby, the company’s chief financial officer and an executive vice president.

Orders for Hovnanian’s homes fell by 18 percent in the three months ended April 30 and cancellation of existing orders by homebuyers rose to 32 percent from 21 percent a year ago. The company, whose earnings jumped 34 percent to a record last year, is expecting a mere 3.4 percent profit increase this fiscal year.

Mr. Sorsby said the company had not resorted to layoffs, but it had been asking sub-contractors to lower labor costs — with some success.

Going forward, many economists say, the biggest question is whether the orderly real-estate slowdown the Fed has engineered thus far will continue. “Outside the threat of surging energy prices,’’ Mr. Zandi said, “the most significant threat to the expansion is that the housing correction turns into a housing crash.”

The fact that mortgage rates remain low by historical standards offers one reason to doubt that a crash will happen. The average rate on a 30-year conventional mortgage was 6.8 percent last week, up from 5.7 percent a year earlier, according to the Fed.

On the other hand, the boom of recent years has pushed housing prices out of reach for many families along the coasts. Already, some homeowners have resorted to creative loans, like interest-only mortgages, to afford a house, and even modest increases in mortgage rates have the potential to cause a significant drop in demand for new houses. In either case, housing seems unlikely to continue being the economic powerhouse it was over the last five years.

“Housing is just not going to be what it has been,” said Edward Yardeni, chief investment strategist at Oak Associates, a money management firm. “It could go back to being a significant but relatively small contributor to economic growth.”

Jeremy W. Peters contributed reporting for this article.

Copyright 2006 The New York Times Company. Reprinted from The New York Times, Business, of Saturday, July 29, 2006.