david 
Choosing a good contractor is very important but often difficult for consumers who know nothing about the roofing industry. In some states, roofers don’t need a license to operate, but if they do in the state you live in, then hire someone with this credential. A licensed roofer has passed a series of written and practical exams, and can guarantee you of a venue in case you have complaints later on.
A lot of roofing contractors have no professional certification and has shown low quality installations and overall workmanship. You’ll want to stay away from them as much as possible, and that is why you have to choose wisely.
Below are points that can help you search for a reputable roofing contractor:
Longevity
One of the most basic things you want to know about a roofer is how long they’ve been a roofer. If they’ve been around for at least five years, they’ve probably been doing something great, knowing how competitive this industry has become.
Permanent Business Contact
Permanent contact information is just another indication of a stable company. Get into a little bit of research. If they haven’t changed their business address, phone number and email address for years, that could be a sign that they’re here for the long haul. That’s in fact one of the most classic signs of a stable company.
Subcontractors
Subcontractors are often paid on a per project basis, which may not be to your best interest. Everyone will be in a hurry so they can accept the next job!
Written Contract and Estimate
It’s a must that all job specs and prices are given to you in writing. Also keep in ind that established company, being financial stable, do not usually ask for a deposit. It’s common for roofers to ask for a down payment though. Just make sure this isn’t more than a third of the total cost.
Consumer Records
Take time out to check with the Better Business Bureau whether your potential roofer has a record of serious complaints from consumers. Look at their rating.
Industry Association Membership
Although membership in an industry association is not an assurance of good performance, it is a sign that the roofer is dedicated to his work.
Warranty
Pick a roofer that provides a workmanship and material warranty. If a roofer hesitates to provide such warranty, look for another prospect._
Insurance
Working with an uninsured roofer is highly risky. They could leave you liable for accidental damage or injuries on the job.
Client References
This part is crucial. When you talk to a roofer’s previous clients, you will have a good view of their capabilities and limitations. If the contractor isn’t likely to give you references, it only shows that they’re hiding something. You need not know what. Just find another roofer.