Cause

 

chalkingChalking is oxidation of the paint film from exposure to the elements and sun. The breakdown of the paints resin and binder causes a fine powder on the surface.  This is a normal weathering process and as paint failures go, this one is the “best” way for a paint to fail. The fix is easy!

Additional causes:

  • Using a low grade paint without adequate UV blockers.
  • Using a paint that uses clay as opposed to titanium oxide in the formula.
  • Using a paint that is over tinted, thinned down or not intended for exterior use.

 

 

Fix

 

Remove the residue by power washing. Occasionally you may need to use a surfactant  to help break the surface tension and remove the chalk. I like “simple green”. It is a very good cleaner and will leave the surface ready to be repainted. Be sure to rinse thoroughly. If after washing you still find chalk on the surface then I would suggest using a high grade solvent based primer.XIM 400 is a good choice.

Be sure to check in regularly for more paint problem fixers! If you found this article helpful, be sure to share, and find more tips and advice at The Painting Company in Omaha!