Alligatoring and Checking
Alligatoring is a type of paint film failure in which the surface develops a cracked pattern with deep relief, resembling a reptile's skin. Checking is a similar failure, but it is less severe and is characterised by long, fairly evenly spaced cracks in the paint film, having shallow relief or depth. Occasionally checking may become severe in some areas, leading to a deeper crack or split in the paint.
Possible Causes
o The second coat of paint was applied over the first coat of primer or paint base coat that had not yet fully dried.
o The second coat of paint was applied over an incompatible paint, such as a glossy paint or a hard oil enamel over a latex-based paint.
o Oil-Based paint has naturally aged and lost its elasticity, leading to cracks caused by fluctuations in temperature.
Possible Causes (Checking)
o Natural aging occurred with several layers of older oil-based paint. As the material that was painted (usually wood) contracts and expands over time, the paint has to move, and it "checks" as it loses elasticity.
Repair and Prevention
o Remove the old paint, then sand, prime and repaint with a flexible latex-based paint.
o Use high-quality latex paint.