WASHINGTON — U.S. manufacturers ended 2011 with their best month of growth since the late spring. And the struggling construction industry spent more on projects for the third time in four months.

The data bolstered hopes that the economy is gaining momentum and helped Wall Street start 2012 with a bang.

Factories hired more workers in December, saw the most growth in new orders since April and ramped up production. U.S. builders spent more in November on single-family homes, apartments and remodeling projects.

The strong reports correspond with other positive signs for the economy. Consumer confidence is up, unemployment benefit applications have tumbled and the unemployment rate is at a three-and-a-half-year low.

Economists caution that Europe’s debt crisis will likely slow global growth in the first half of the year.
But on Tuesday, the outlook was mostly positive.

The Institute for Supply Management, a trade group of purchasing managers, said its manufacturing index rose to 53.9 from 52.7 in November. Readings above 50 indicate expansion.

The Commerce Department said spending on construction projects rose 1.2 percent in November. The increase was the largest since a 2.2 percent rise in August.

“The trend for the U.S. economy is most decidedly to the upside,” said Dan Greenhaus, an analyst at brokerage firm BTIG LLC in New York.

U.S. manufacturing has expanded for more than two years. Factories were one of the first areas of the economy to start growing after the recession officially ended in June 2009. They faltered over the summer after Japan’s March 11 earthquake disrupted auto and electronics supply chains.

The December ISM survey showed many factories have largely recovered from their slump earlier this year.

Exports rose despite the trouble in Europe. Growth in new orders means output will likely increase in the coming months. And U.S. factories hired last month at the fastest pace since June, an optimistic sign ahead of Friday’s important measure of job growth in December.

“All in all, an upbeat report,” said Peter Newland, an economist at Barclays Capital, who noted that the stronger manufacturing activity should contribute to faster economic growth in the October-December quarter.

Construction spending rose 1.2 percent in November to a seasonally adjusted annual rate of $807.1 billion. While that’s barely half the $1.5 trillion that economists consider healthy, home construction has begun a gradual rebound and likely added to the nation’s economic growth in 2011.