Alligatoring

Definition

Patterned cracking in the paint film resembling an alligator’s scales. Cracks may affect only a single layer of paint and may not reach the surface.

Progression

May begin as slight cracking or “checking" and can eventually grow wider and deeper, breaking through top and bottom coats. Noticeable wide breaks can appear over the entire surface in the worst cases.

Causes

• Inability of the top coat to bond smoothly to a glossy finish
• Applying an extremely hard, rigid coating (e.g., oil-based paint) over a more flexible coating
• Natural aging of oil-based paints in extreme climates, when subjected to continuous freezing and thawing, which results in loss of paint elasticity
• Applying another coat before the previous coat has dried
• Applying too much paint per coat

Solutions

• Scrape or sand the paint down to the bare surface or use a chemical paint remover. Dust masks or respirators and eye protection are recommended for safety. If using liquid removers, be sure to wear long sleeves and gloves.
• Remove all dust and allow the surface to dry completely.
• Prime the surface with a high-quality latex primer and let it dry completely.
• Apply a high-quality paint in the desired finish.