This is good advise from Lake County government:
Early warning signs of an unlicensed contractor
A large down payment is requested before work begins.
Many requests for money during early phases of construction.
The homeowner is asked to obtain the permit.
Verbal contract only, the person is not willing to put all terms in writing.
The contractor does not have proof of insurance.
The contractor informs the homeowner that the job does not require a permit or inspection. (To verify if a permit is actually required, call Building Services at (352) 343-9653.)
The contractor is only willing to work on weekends or after hours.
Someone other than the person or company contracting to do the work obtains the permit.
Contractor displays only a business tax receipt. (An business tax receipt [aka occupational license] is not a license to perform contracting work.)
The homeowners is asked to make checks payable to an individual when the contract is with a company, or asked to make payments in cash, or to make the check payable to "cash."
Newspaper advertisements, flyers or yellow page advertisements where only the telephone number appears and there is not a business address.
License numbers are not on the vehicle, business cards, contracts, flyers, newspaper or yellow page advertisements.
The homeowner can also ask questions
Ask what type of license they have. The license should be issued from Lake County Building Services or the Department of Business and Professional Regulation.
Ask to see a copy of their license. To lawfully engage in contracting, a contractor must be either State Registered or State Certified, or Locally Licensed.
Ask for a copy of their liability and workman's compensation insurance. Licensed contractors must have general liability and workers compensation insurance in force at all times.
http://www.lakecountyfl.gov/departme..._yourself.aspx