DES MOINES -- The business is welcome, but Kenny Capron wishes the work was available for some other reason.

First came a tornado in Parkersburg, New Hartford and Dunkerton, then flooding ruined neighborhoods and forced thousands out of their homes in Cedar Falls, Waverly, Charles City and other Iowa communities.

"It's gut-wrenching," the co-owner of Parkersburg Lumber says.

Capron knows some of those who lost their homes May 25 when Iowa's most powerful tornado in 32 years leveled about a third of Parkersburg, killing eight people. Less than three weeks later, floods that devastated so many towns poured into Cedar Rapids, inundating downtown and thousands of houses.

Damage from the tornado and flooding has topped $4 billion and likely will increase, leaving individuals and government entities with staggering reconstruction bills.

For contractors and some businesses, the misfortune created a chance for work after other jobs dried up.

"The housing industry, contractors and subcontractors who have been idled, they're going to have some growth in all this," said Meghan O'Brien, an economist at Iowa State University.

Struggling retailers will also benefit as residents replace ruined furniture, carpet and electronics, she added.

O'Brien and others said losses from the disasters more than offset the gains to construction. And the experts are quick to note few want to benefit from others' misery, but they said many people could use the extra work.

"Residential construction has been very weak," said Bernard Markstein, an economist for the National Association of Homebuilders.

So far, about 440 contractors throughout the country have registered with the state to help in the relief effort, according to Iowa Workforce Development. O'Brien expects that number to grow.

"You will likely see people from less affected areas moving to those areas to provide more resources," she said.

Kerry Koonce, a spokeswoman for Iowa Workforce Development, said the state should have plenty of workers to get jobs done and more are on the way.

"We see people coming in from everywhere," Koonce said. "In large-scale things like this, you'll see East and West Coast contractors bringing in crews."

Contractors coming to the disaster areas face a daunting task.

In Cedar Rapids, where at least 4,000 homes need repairs, they'll tackle projects such as Wes Stripling's home. The one-story house was submerged in 10 feet of water for days, causing so much damage that Stripling thinks the structure may be beyond repair.

"Most of the folks in this neighborhood are in that position," he said. "The water damage is so extensive."

Ritch Kahler, who operates a medical supply company out of his home in Cedar Rapids, is concerned about finding a contractor.

"There were five homes in my family alone that took some damage," he said. "We could get a waiting list going just inside of our own family."

He said just about everything in his home must be replaced, including plumbing, the electrical system and floors.

"We're definitely a little bit worried about finding a contractor quickly," he said.

Cedar Rapids Fire Marshal Jim Thatcher said the city enacted a moratorium on repair work until this week, giving officials time to review each contractor's application to ensure they are qualified to work in flood-damaged areas.

"It's important, for the sake of our citizens, to get the work done right," said Thatcher, whose department is overseeing the registration of contractors.

Then there's Parkersburg, still working to clear debris after a tornado ripped through the town of about 1,800 people.

"I look at all these piles around town and wonder if it will ever all get picked up," Capron said.

He said the town will be lucky if 60 percent of the homes destroyed are rebuilt by fall.

"There's only so many people, so many contractors."

O'Brien, the economist, said rebuilding costs could increase to match the demand for materials and supplies.

"There will be upward pressure on prices because of increased demand," she said. "As you see the demand for lumber and supplies and drywall increasing, the price will go up."

Jamilah Fraser, a spokeswoman for the Federal Emergency Management Agency, said homeowners may qualify for up to $28,800 in relief. Homeowners, though, must first contact their insurance carrier before applying for federal assistance.

"It's only for a person's primary residence and for some uninsured costs," Fraser said. "FEMA cannot duplicate benefits."

Fraser said homeowners can also apply for benefits from the U.S. Small Business Administration, which can approve loans for home repairs.

Fraser said federal aid is approved on a case-by-case basis, but she cautioned people not to expect federal assistance to fix everything.

"A lot of people expect FEMA to make them whole again, and that is not the case," Fraser said. "It's here to assist them and provide critical support as victims move toward long-term recovery."

Associated Press writers Henry C. Jackson in Cedar Rapids and James Beltran in Des Moines contributed to this report.