How to Wash Walls With TSP

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Trisodium phosphate is a strong detergent -- so strong that it can cause skin burns. There's no doubt that it will get your walls clean, whether they're plaster, drywall, masonry or wood, but it's too strong to use as an all-purpose cleaner. The best use of TSP is for emergency cleaning -- for example, removing soot from a fire -- or to prepare your walls for a fresh coat of paint.

What Is TSP?

Trisodium phosphate -- also known as sodium orthophosphate dodecahydrate -- is a naturally occurring powder consisting of sodium atoms and combinations of phosphorous and oxygen atoms known as phosphates; its chemical formula is Na3PO4. Because of their ability to emulsify and remove dirt and grease, phosphates were common in laundry detergents and household cleaners until their harmful effects on the environment became apparent in the 1980s, and they were widely banned. TSP is still available, although many people prefer to use a substitute.


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Uses for TSP

Because of its ability to emulsify and dissolve, TSP has a number of uses, including:

  • Degreasing
  • Stripping paint
  • Cleaning paintbrushes
  • Preparing driveways for sealing
  • Heavy-duty cleaning


Because TSP is mildly corrosive, you usually have to repaint any painted surface you clean with it. For this reason, painters often keep it around for cleaning walls they are about to repaint.

Using TSP Around the House

Generally, TSP isn't the product you need for routine housekeeping. If you need to wash walls, it's safer to use mild soap and water, adding ammonia if needed. Because of its superior cleaning ability, though, you may decide to use TSP as a last resort to clean stubborn stains or grease spots. It's strong in any concentration, so for walls, a mixture consisting of 1/4 cup per gallon of water is usually sufficient. If you need a very strong cleaner to remove something like soot or kitchen grease, you can mix as much as 1 cup of TSP per gallon.


Washing Walls With TSP

Handle a TSP solution like any soap solution, keeping in mind that it's stronger than most and must be handled with respect.

Step 1

Put on rubber gloves and goggles. TSP can cause mild burns on bare skin, and it can permanently damage your eyes.


Step 2

Pour the powder into a bucket of warm water and stir until it's completely dissolved.

Step 3

Wash the walls with a sponge, squeezing the sponge out in the TSP solution as needed to keep it clean.

Step 4

Rinse the walls with clear water after cleaning.