Some 1.6 billion people in the world live in slum housing without running water, with leaking sewers or faulty wiring.
Others live in tents, and it's not just somewhere else. It happens in America, said Steve Thomas.
"You can't run a world this way. It's going to blow up. So you have got to do something," said Thomas.
The Emmy Award-winning television personality and former host of the home improvement shows "This Old House" and "Renovation Nation" was the star of Habitat for Humanity's Home Builders Blitz 2014 celebration Wednesday at the Bethlehem Center.
Thomas said he got involved with Habitat after traveling the world and seeing people live in substandard housing.
Nearly 200 people including contractors, professional home builders and developers met at the Bethlehem Center to share a barbecue lunch and celebrate their combined efforts to build two homes and renovate another in Chattanooga's Southside neighborhood.
Some donated time, while others gave gutters, building material, money or T-shirts.
They are a part of Habitat for Humanity's home builders blitz, a nationwide effort to build more than 250 homes in five days this week.
"Thank you for making dreams come true," said Tom Gipson, who founded Habitat for Humanity's Home Builders Blitz.
Habitat is building two new homes, one in Alton Park and the other in the Southside, and renovating another.
"You can totally change someone's life," said Thomas.
A local single mother of two daughters looks forward to a house with more space for her family.
For more than a year, 39-year-old LeShundria Nelson and her two daughters, ages 9 and 17, have shared a one-bedroom apartment with her father.
But around the end of August she expects to move into the first Habitat home built in the Villages at Alton Park. Several people from the blitz celebration took pictures in front of the home after the kick-off Wednesday
"Having my own home is something to be proud of and it's something that I worked for," said Nelson.
Nelson, as all other Habitat families, contributed 250 sweat equity hours and took homeownership classes to get her home.
Thomas noted that Habitat is the 10th largest home builder in the United States.
Contact staff writer Yolanda Putman at firstname.lastname@example.org or 423-757-6431.