First thing you have to do is get minimum 3 estimates from various companies but you should not chose the lowest one immediately because initially you need to do is little researches.
When you are going to select the company that time you should look some important things about the company such as when can they start, how long they will take to complete the project, they have the license or not and if you face any problem then they will repair it or not. You should ask them directly and they are bound to give you the answer. It is very important to know about their credentials. It does not matter that lowest priced company is the best. You should know that it may take some extra cash than the actual contract and the terms and conditions of the contract are very important so you should understand it very clearly. Before signing the contract you need to talk with them about the safety issue. There is always risk that someone could get hurt during the work day so safety comes first. After all construction is not a safe career and anything can happen at this time.
Roofing company should have the compensation insurance. As a homeowner you may deposit some cash to the roofing contractors or the company because it is taken as a safety deposit. A well communication should be always there between you and company’s representative so that you can be updated about the progress. If you follow these advices then you can be sure that your choosing of roofing company is right at any time.