Make Sure; You hire a Roofing Contractor That Completes the Project Right The First Time. Once your professional roofers have fixed the underlying cause of the moisture, they will need to replace all the wood affected by the dry or wet rot. Leaks and condensation are the two most common causes of a rotting wood deck. It makes sense to look for deck rot around notorious leak points, such as skylights, roof penetrations and anchor points for roof-mounted items. In order to fix the problem, you first need a professional roofer to resolve the underlying leak.