When hiring a professional roofing company or roofer it is very important that the roofing contractor be licensed. Roofing work can be dangerous so if you have a person who is unqualified to do the work they can do more harm than good. If they are injured and are not licensed you could be liable for their medical bills. In the United States, many of the states have a law that says a roofer can only work if they are licensed. The licensing procedure is different for every state so you will need to check out the requirements to obtain a license in your state.
To get a roofing contractor license you have to pass one or more tests. You also have to provide proof of having on-the-job experience for a specified amount of time or proof showing that you have formal training. Some of the material that is covered in the tests to get your license can include construction laws, safety requirements, and more. When they get their license, they are telling their customers that they have field knowledge of the techniques to repair or replace roof, materials used, and give the customer a professional looking roof.
Some roofing contractors will only secure a general contractor's license, which means that you have no experience in any field except from roofing but because you have a general contractor's license you are now registered to work as a plumber or electrician. If you ask to see their roofing contractor license and they show you a general contractor's license you have no idea what type of work they have a specialty in. Ask to see a portfolio of the roofing work they have done. You can also get a list of references and a couple of addresses where you can view their previous work. If you do not know the roofing contractor there is a small chance that these are friends of his and he did none of the work. This is why it is important that you just hire a roofing contractor that can show you a professional roofer's license. Their work will be done correctly.
In addition to being licensed, a roofer will need to be insured and bonded. When a roofer is bonded, it means that they have the secured funds to pay for any damages they may cause to your landscape, shoddy workmanship, and more if you take them to court and win your case. Being insured means if they or one of their employees gets hurt on the job you will not be responsible for any of the injured one's medical bill. The roofing company is the one responsible for these medical bills and any other compensation that is due to them.