Alligatoring is the patterned cracking in the surface of the paint film resembling the
regular scales of an alligator.

Possible cause
- The application of an extremely hard, rigid coating (like a solvent-based enamel) over a more flexible coating, like a water-based primer
- Applying your topcoat before the undercoat is dry
- The natural aging of oil-based paints as outdoor temperatures fluctuate. The constant expansion and contraction of the paint based on the temperature can result in a loss of paint film elasticity
Solution
Old paint should be completely removed by scraping and sanding the
surface; a heat gun can be used to speed work on large surfaces, but take care to avoid igniting paint or substrate.
The surface should be primed with a high quality water-based primer and then painted with a top quality exterior water-based paint. Dulux recommends Dulux Weathershield® for a premium exterior paint.
More problem solving advice
Tannin staining
Brownish or tan discoloration on the paint surface due to migration of tannins from the substrate through the paint film.
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Alligatoring