When Habitat for Humanity throws a party this summer, they'll raise the roof - two of them, in fact.

The non-profit, humanitarian organization plans to construct two houses for low-income families before fall, using the skills and commitment of several hundred Utahns."We have about 350 people on our membership mailing list," Bob Gerdes, former chairman, said. "There are 100 people who donate six or more hours a month, and we have 50 who donate four to six hours a week. The rest fall somewhere below that."

Those people come from all walks of life, all age categories and education levels. The thing they all have in common, said Gerdes, is concern for others. "The organization crosses a lot of boundaries. Most of us are Christians, but we don't exclude non-Christians."

Habitat for Humanity, which has chapters across the United States, helps low-income families purchase houses for the market value of the house, less the real estate service costs, which are donated, with no-interest loans.

"Putting people in homes is such a simple concept when you wipe out the interest factor," said Larry Skiffington, an attorney who donates legal work to the group. "We build or find homes to suit the family, rather than the other way around."

"We believe that all people need decent housing and shelter," Gerdes said. "Some are renovated homes, some we build, some we move into place. The ones this summer are new construction. We have a volunteer from Ohio who teaches industrial arts, and he's teaching us to build houses."

Gerdes said that Habitat offers help to people who have demonstrated stability in the community and will be able to repay the debt, usually on a 20-year no-interest loan. Participants must win approval from the family selection committee, which is made up of people with all sorts of backgrounds, expertises and interests. The terms make housing available to people who might otherwise not be able to afford it. And in the process of planning a new home, the group offers more to the family than just a roof. They offer support and friendship and encouragement.

"Once these people have a group that nurtures them, it's amazing how they can turn their lives around," Gerdes said.

Then there's an unexpected result, according to Skiffington. "All over the country we've seen that if you build two or three nice `humanity' houses in a neighborhood, pretty soon everyone is cleaning up their yards, too. Independently. I think that's a delightful side-effect."

Habitat is growing rapidly nationwide, particularly as it gains more attention. Former President Jimmy Carter and his wife have become spokesmen for the group and serve on its national board of directors. Anyone interested in joining the Salt Lake chapter should call 266-6748.