Alligatoring: The cracking of the surfacing bitumen on a builtup roof, producing a pattern of cracks similar to an alligator’s hide; the cracks may or may not extend through the roof membrane. Alligatoring is commonly found on smooth surface asphalt roofs. It is caused by the drying out of the exposed asphalt surfacing by the sun. When left unattended, cracks and splits eventually develops. Water will enter the roofing system and cause unseen damage in the roof system. Smooth built up roofs should be inspected annually for damage.