Jimmy and Rosalynn Carter kick off 35th Habitat for Humanity build in Indiana

Former U.S. President Jimmy Carter smiles during a book signing event for his new book 'Faith: A Journey For All' at Barnes & Noble bookstore in Midtown Manhattan, March 26, 2018 in New York City. Carter, 93, has been a prolific author since leaving office in 1981, publishing dozens of books. (Photo by Drew Angerer/Getty Images)

Credit: Drew Angerer

Credit: Drew Angerer

Former U.S. President Jimmy Carter smiles during a book signing event for his new book 'Faith: A Journey For All' at Barnes & Noble bookstore in Midtown Manhattan, March 26, 2018 in New York City. Carter, 93, has been a prolific author since leaving office in 1981, publishing dozens of books. (Photo by Drew Angerer/Getty Images)

Former U.S. President Jimmy Carter and wife Rosalynn Carter kicked off the 35th annual Carter Work Project for Habitat for Humanity in Indiana on Sunday evening.

The former president has long been an advocate for the organization, which builds homes using volunteer labor and gives sells to people who are in need of affordable housing and pay an interest-free mortgage. Before Carter got involved, the organization had built fewer than 1,000 homes; since then, more than 13 million have been built, said Jim Williams, president and CEO of Habitat for Humanity of St. Joseph County, Indiana, which is hosting this year’s build.

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The Carter Work Project takes place once a year, and is a weeklong drive to build dozens of homes in one city or region. This year’s event, in South Bend and Mishawaka, Indiana, is expected to produce 22 new homes; 41 homes in total will be built, renovated or repaired between Aug. 27 and 31, according to Habitat for Humanity.

The Carters thanked a crowd of volunteers and supporters at the University of Notre Dame’s Purcell Pavilion, after receiving a surprise introduction from comedian and Indiana native David Letterman. Former President Carter reflected on the positive impact working with Habitat for Humanity has had on his life.

“This Habitat (build) is not a sacrifice,” said Carter, who’s 93. Rosalynn is 91. “We sometimes get too hot, sometimes get too cold, sometimes work overtime, but every time we’ve ever been out as volunteers, whether this in country or around the world, at the end of the habitat project, we always feel that (Rosalynn) and I got more out of it than we put into it.”

The first hammers will start swinging early Monday morning.

READ: What else is Jimmy Carter known for? 10 of his major accomplishments

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