A friable,powdery layer on the surface of a paint film. A change of colour or fading is also seen.Chalking rates vary with pigment concentration and choise of binder. Chalking is a known characteristic of certain paints e.g. epoxy paints.
Probable Causes: Disintegration of the paint binder on exposure to weathering and/or UV light.
Prevention: Apply a suitable topcoat with high resistance to chalking, and with UV resistance.
Repair: Remove all powdery deposits by wiping, scrubbing,high pressure washing or abrasion. Wipe loose material off and apply a chalk resistant topcoat.