The Advantages of Hiring a Professional Roofing Contractor     The most important part of maintaining your roof is to get the job done right the first time. This is where a licensed, insured roofing contractor comes in. He is the pro -- someone who will deliver an effective, long-lasting roof and stand behind his work. Professional roofing contractors are: Licensed. The State of New York City has adopted standards for licensing roofing contractors. Only those who meet the standards by testing qualify for a state license. Well-established. A professional roofing contractor will have a permanent place of business, a telephone number, a tax identification number and, where appropriate, a business license.  Well-established. A professional roofing contractor will have a permanent place of business, a telephone number, a tax identification number and, where appropriate, a business license. Experienced and knowledgeable. Roofing skills cannot be learned overnight. A professional roofing contractor is familiar with all kinds of roofs -- asphalt and gravel, wood shingle and shake, composition shingle, tile and slate, as well as various kinds of specialty products such as modified bitumens, EPDM and PVC. Insured, and committed to safety. There are inherent dangers to applying a roof. The contractor who carries both workers' compensation and liability insurance has protected you in the event of damage to your property and injury to his workers while work is being performed on your property. Insured, and committed to safety. There are inherent dangers to applying a roof. The contractor who carries both workers' compensation and liability insurance has protected you in the event of damage to your property and injury to his workers while work is being performed on your property.