Chalking

 

Formation of a fine powder on exterior paints which affects the appearance of the coating and can cause gloss and colour fading.

Formation of a fine powder on exterior paints which affects the appearance of the coating and can cause gloss and colour fading. There are two levels of chalking: light and heavy. Light chalking is removed by rain. Heavy chalking, however, leaves residues on the coating and reduces the surface protection.

Causes

  1. Use of a low-grade product.
  2. Over thinning or overspreading the paint.
  3. Use of an interior paint for an outdoor application.
  4. Lack of maintenance.
  5. Overly high application temperature.

Solutions

  1. Also for causes 2-5: When chalking is light, clean and repaint the surface with a higher quality coating.  In case of heavy coating, clean the surface and apply a base coat before repainting.
  • Surfaces facing South and West require more frequent maintenance.