What is alligatoring?
Alligatoring is a pattern of interconnected cracks in paint that resemble alligator skin, typically caused by aging oil paint, UV exposure, or applying new paint over incompatible surfaces without proper preparation.
When paint begins to crack into a pattern resembling alligator skin, you are looking at alligatoring. The surface breaks into a web of interconnected fissures and scales rather than simple linear cracks. This happens most often on exterior wood surfaces where oil-based paint has aged over years of exposure to sun and weather.
The root causes fall into two main categories. First, old oil paint naturally becomes brittle as it oxidizes and loses flexibility. Temperature swings and moisture cycles cause the wood substrate to expand and contract, and the inflexible paint layer cannot move with it, so it fractures. Second, alligatoring occurs when new paint is applied over old paint layers that do not bond properly, such as applying latex over aged oil or stacking incompatible coatings without stripping.
Alligatoring signals that surface preparation has failed. Simply sanding and repainting will not stop the problem from returning. The paint must be stripped down to bare wood to break the cycle of adhesion failure and cracking. This is why professional painters recognize alligatoring as a sign that full surface preparation is required before new paint can be applied reliably. Contractors offering exterior painting services can assess whether a surface has reached this point.