Alligatoring on BUR

Cracking of the surfacing bitumen on a bituminous roof or coating on a spray foam roof and produces a pattern of cracks similar to an alligator’s hide. The cracks may not extend completely through the surfacing bitumen or coating. When left unattended, cracks and splits eventually develop. Water will enter the roofing system and cause unseen damage in the roof system. As the surfacing layer fails, the fiberglass reinforcement underneath is exposed and becomes brittle. Membrane failure inevitably follows.

Smooth built-up roofs should be inspected annually for damage. A roof coating may be applied to reflect harmful ultraviolet rays and reduce thermal cycling.


The cracks are bigger than hairline to about the thickness of a credit card. The scales are mostly no bigger than 1/2" and do not easy come off the roof.


Cracks are wide and deep. The scales are mostly larger than 1/2". You may need to use a resaturant to rejuvenate the old asphalt.