Ask the Atlanta roofing company of who could serve as references with regard to their work. If the roofing company has a good reputation it would gladly give you the list of the customers they have served in the past. Of course, they would not give you those who have unsatisfied outputs so you can go and check on the Better Business Bureau. It is in this bureau that you can find the filed complaints against the company. Also consider how the roofing has handled the complaints against them.