How to Prepare Walls For Paint With TSP

Trisodium phosphate, also known as TSP, is very popular among homeowners and contractors when heavy-duty cleaning is required.

Preparation is the key to a nice paint job.Preparation is the key to a nice paint job.
TSP's powerful degreasing ingredients make it an effective product to use while preparing surfaces such as walls and framework around doors and windows for painting. Mold, mildew and smoke stains are easily removed by this powerful cleaner. TSP is not recommended for use on glass. Protective gloves and eye wear should be worn at all times when using it.

Cover the floors in the work area with painter's plastic.

Put on protective gloves. Dissolve one half cup of trisodium phosphate in 2 gallons of hot water. Prepare one bucket of hot water for rinsing.

Soak a clean rag in the water containing the cleaner. Remove excess water from the rag by wringing it out.

Wash the walls with the rag soaked in TSP. Start from the top of the wall and work down. Rinse the walls using a clean rag and clean water. Use separate buckets for wash water and rinse water. Refill the rinse bucket with clean water when it becomes discolored.

Repeat washing the walls and then rinsing them until they are clean. Allow the surfaces to dry completely before painting.

Things You Will Need

  • Painter's plastic
  • TSP
  • Protective gloves
  • Protective eyewear
  • Clean rags
  • 2 buckets


  • TSP is highly alkaline so it is not recommended for use on aluminum because the contact may produce hydrogen gas.
  • Read all warnings and precautions before using trisodium phosphate.

About the Author

Mona Culberson began working on the assembly line at a large manufacturing company in 1983, where she worked her way up into several positions of business responsibility. In 2005, she began a career in roofing, interior design and remodeling. She works daily as a professional painter/home remodeler/handywoman while lending her husband's roofing business a helping hand in her spare time.