HARVEY, La. (AP) — Cycling champion Lance Armstrong brought more than 50 volunteers to this New Orleans suburb to help build homes for needy families Tuesday.

Wearing a ball cap, T-shirt and tool belt, Armstrong toured one of about a dozen homes under construction. Saying he’d ‘‘never hammered anything before,’’ he helped nail siding to a front porch — with his first attempt resulting in a bent nail that he had to remove and drive again.

‘‘You put a roof over somebody’s head, they will not go back into poverty,’’ he told a news conference at the Harvey site, where he announced his foundation is donating $50,000 to the New Orleans area Habitat for Humanity.

Habitat has roughly 200 homes currently under construction in the New Orleans area but plans to build 1,500 homes over the next five years, said Jim Pate, executive director of the New Orleans Habitat organization.

Armstrong’s donation brings to $500,000 the total his Lance Armstrong Foundation has given to the region since Hurricane Katrina hit in August 2005.

On Tuesday, he recounted how his foundation helped cancer patients evacuate New Orleans in Katrina’s wake and get necessary treatment in other cities.

‘‘It was one of the proudest moments in the life of this foundation, because we acted so quickly,’’ he said.

The Austin, Texas-based foundation was established in 1997. Since the storm, it has provided more than 1,000 storm victims with housing, transportation and other basic needs.

Gov. Bobby Jindal, who attended Tuesday’s news conference along with Lt. Gov. Mitch Landrieu, said Louisiana has the highest cancer mortality rate of any state. Armstrong said he would do public service announcements on the subject and whatever he could to spread the message that early detection saves lives.

‘‘Early detection leads to cures,’’ he said.

Armstrong was diagnosed 12 years ago with testicular cancer that spread to his lungs and brain. But he recovered to win the Tour de France from 1999 to 2005.

Armstrong plans to run the Boston Marathon in April to raise money for his foundation, which supports cancer research, prevention and better care for cancer survivors. Armstrong and others running for the foundation raised about $500,000 at last year’s New York City Marathon.