Coating defect
Wrinkling
A rough, shrivelled surface of ridges and valleys, like the skin of a prune, often on flat surfaces where a heavy coat was laid.
Causes
- Film too thick: the surface skins over while the paint below is still soft.
- Oxidative coatings such as alkyds, which cure from the surface down.
- Heat or sun on the fresh film, or recoating a coat that is not dry enough.
- Rain, dew or high humidity on uncured paint.
Prevention
- Apply even coats at the specified wet film thickness.
- Keep to the drying times and temperatures of the product data sheet.
How it is assessed
Visual. Check the wet and dry film thickness records and the conditions during cure.
Repair
Remove the wrinkled coat to a sound surface, sand or abrade it smooth, and recoat at the right thickness. The specification and the coating manufacturer have the final word on the repair procedure.
15 practice items in the members area mention wrinkling (CIP 1: 2 · CIP 2: 11 · FROSIO written: 2).
Related
Try it in an exam-style question. The free readiness check shows the question style, explains every answer and gives you a dated study plan.
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Written from coating practice and the published rating standards, in our own words; the drawing is schematic. Checked on 2026-10-14; errors go in the corrections log. CoatMentor is an independent study aid. It is not affiliated with ISO, AMPP, SSPC, NACE International, ASTM or FROSIO.