How to Clean Paint Chalking

Paint chalk is a powdery substance that commonly forms on painted exterior surfaces exposed to frequent sunlight or dry weather. The powdery chalk is paint pigment residue escaping from underneath the weathered coating. Excessive chalking causes the color of a paint finish to fade and chalk exposed to rain may also leave noticeable streak marks on the surface. Cleaning chalking paint is an essential step for a successful exterior repainting project. Painting directly over chalk prevents proper paint adhesion leading to paint failure and additional chalking.

Chalking paint ruins the look of a home.
  1. Put on a pair or rubber chemical gloves and wear safety glasses.

  2. Mix trisodium phosphate and warm water in a 5-gallon bucket with a stir stick. Follow the mixing directions noted on the container. Trisodium phosphate breaks down dirt and powdery chalking paint.

  3. Dip a hard bristle scrub brush into the bucket and begin scrubbing the chalking paint. Apply pressure to penetrate the painted surface with the cleaning solution.

  4. Hose down the surface with a garden hose to wash off the old paint pigment, dirt and trisodium phosphate residue. Allow the surface to completely dry.

  5. Run your finger over the cleaned surface to check for evidence of chalking. If chalking powder appears on your finger, repeat the cleaning process a second time using the same cleaning method. Rinse off the surface thoroughly with the garden hose after cleaning.


  • Do not paint over chalking paint without thorough cleaning.
  • Do not leave trisodium phosphate residue on the surface.
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