Roof leaks can be one of the most damaging of all defect types and, for the homeowner, certainly one of the most alarming. Roof leaks may appear as stains on the interior drywall surfaces and ceiling, or they may be hidden within the structure itself. After any major rain, check for staining that may form in the ceiling drywall surfaces or adjoining wall surfaces. Although there may be many sources for the water intrusion, most common types are: inadequate grout and sealants applied to the roof ridge, inadequate flashing and counter-flashing that fail to provide an adequate seal against the headwall, and improper eave construction which allows water to pond at the roof edge.