The state of Alabama requires any general contractor working on a commercial or industrial project costing $50,000 or more to get a license. If you're the general contractor on a residential project that costs $10,000 or more, you need a license.
Look at Chapter 8 of Title 34, Code of Alabama, 1975
Also LINK
The Compliance/Regulatory Division for Alabama number is 334-272-5030
The investigator for north Alabama number is 334-328-2629