Washington — When Ivie Myntti, a U.S. high school senior, traveled to Udon Thani, Thailand, in February 2008 as a volunteer for Habitat for Humanity International, she wanted to have fun, travel, but also leave an effect on the local community.

“I think a lot of students notice that our planet is in trouble and we need to do something about it, whether it is helping people, animals or the environment,” Mynitti said. “I do think the work we did made a difference in the community; at least it made a difference to the family we built it for.”

Myntti, like many other volunteers, built walls, mixed cement for floors and helped Habitat, an organization known for providing families in need with homes of their own, construct one of several houses in Udon Thani.

Growing numbers of U.S. volunteers are leaving their jobs and schools for a few weeks each year to help construct housing in disadvantaged communities worldwide, from the earthquake-damaged Kumsangir region of Tajikistan and the frozen lands of Siberia in Russia to Kyrgyzstan’s capital of Bishkek and the village of Nshavan, Armenia.

Habitat operates in 92 countries and has provided low-cost housing for more than 1.5 million people, the organization reports. Since its founding in 1976 by Alabama-born lawyer and businessman Millard Fuller and his wife, Linda, Habitat for Humanity International has built and rehabilitated more than 300,000 houses, the most recent in November 2008 in Zacapa, Guatemala.

In 2007, Janine Zajac, then a 22-year-old student at the University of Michigan, traveled to Escuintla, Guatemala, where, as part of a Habitat project, she mixed concrete, chopped concrete blocks with machetes and constructed foundational supports.

The experience, she said, changed her life. “It opened my eyes to the benefits and importance of service, and, consequently, the trip shaped my path in life because it made me realize that I could use my career as a means to help other people.”

It was physically demanding, Zajac told America.gov, but “Habitat showed me that there is so much more to do in this world than sit behind a computer traipsing around on the Internet or sitting in front of a television and keeping up with pop culture.”

Participants say the hard work pales in comparison to the joy of being able to help a family have someplace to call home.

The need being addressed by Habitat is huge. According to a 2005 report by the United Nations, nearly 32 percent of the world’s population live in urban slums and 100 million people are homeless.

Although no official figures are available, a review of Web sites of local and regional groups suggests that U.S. volunteers for Habitat number in the tens of thousands, possibly even hundreds of thousands, and come from places including college campuses, youth groups, religious institutions, corporations and sporting clubs. In New York alone, the number of volunteers annually exceeds 10,000, according to the local affiliate’s Web site.

The organization also receives important support from the U.S. business community. Whirlpool Company, for example, donates thousands of ovens and refrigerators. The Home Depot Foundation provides building supplies. Employees from several large financial firms, such as Bank of America and Citicorp, have volunteered hundreds of thousands of hours.

In 2002, Habitat developed its first relationship in Russia with the construction of a house in the Buryatia Republic’s capital city of Ulan-Ude in southern Siberia. As Habitat continues to rebuild dilapidated houses, as well as construct brand new homes in the region, local media interest and local government support is growing.

Partnerships with communities in Tajikistan, a country whose economy is still reeling from the effects of a long civil war that followed independence in 1991, have helped to build more than 303 houses since Habitat first became involved in 1999. The local government in Khujand, a city in the northern part of the country, donated land for more than 80 homes, and local donors provided $37,000 for the project.

After Hurricane Katrina hit the southern coast of the United States in August 2005, Habitat was one of the first organizations to start rebuilding homes. Three years later, Habitat is still helping the recovery effort, building 52 homes a month in the areas most affected by Katrina.

“We have become small players in an exciting global effort to alleviate the curse of homelessness,” says former U.S. President Jimmy Carter, one of Habitat’s more famous volunteers, who takes time each year to help rebuild houses.