Roofer put on & generally require formal education, however they require on-the-job experience to discover their trade. While each state has various licensing guidelines, most require a roofer to have at least 2 years of experience before they can become licensed. These professionals also need liability insurance, to be bonded and to possess a company license. HomeAdvisor can help you discover the right roofing contractor for your task. While each state has various licensing rules, many need a roofing contractor to have at least two years of experience before they can become licensed. These experts also require liability insurance, to be bonded and to possess a business license.