Before asking how much the new porch will cost, ask to see the license to build it.

For a month, all general contractors in Georgia have been under a new law that requires them to have state licenses to build a house or change the structure of one.

"If you don't have a license, you don't pull a permit, you don't start a house," said Ernie Blackburn, the president of the Builders Association of Metro Augusta.

The 22-year Columbia County home builder was one of the 19,300 Georgia contractors who got his license before the July 1 deadline. Because of his years of experience, he was also one of the 11,500 contractors who didn't have to take the exam.

While certain trades have had to carry a license -- plumbers and electricians, for example -- the general contractors overseeing them did not, Mr. Blackburn said. The state instituted a license requirement for builders and contractors to raise the bar on construction practices.

"It is not just a good thing for the consumer, the home buyer, but for our industry, particularly for reputable builders who want to raise the standards," Mr. Blackburn said. "If there are some bad apples, this system is going to have a way of weeding them out."

Mr. Blackburn said the local builders association has been advocating licensure for a decade.

South Carolina, Tennessee and Florida already have similar requirements.

The licensing comes with some nuances: Not everyone who works on a building needs one.

Mark Birch, the owner of Window World, doesn't need a license to install replacement windows. Any project that involves changing the structure of the house, however, would require that license -- and he asks to see it when he's hiring a subcontractor.

Roofers and painters also would not have to get a license because they aren't changing the structural integrity of the home.

Though local builders haven't needed a state license, each county has a department that issues building permits and inspects projects during construction.

Robert Sherman, the director of Richmond County's license and inspection department, said a certificate of occupancy isn't issued until a new building passes its inspections.

Mr. Sherman said members of his staff performed 10,000 inspections -- and only 991 re-inspections -- from Jan. 1 to July 30.

Columbia County has required a local license for the past three years. The county is trying to determine whether it is needed now, Mr. Blackburn said.