There are many risks involved in the construction site. Hence it is important to hire a legitimate commercial roofing contractor. He should have workers' compensation insurance, general liability insurance and business license. If these factors are not taken into consideration, in case of an untoward incident, the owner will have to spend a huge amount. You should settle the deal only after getting copies of all the important documents from the roofer. You should give preference to persons with permanent business address. Also you should make sure that the roofer uses materials of superb quality for the work.