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