How to Clean Exterior Paint

An inexpensive way to spruce up the outside of a building is to clean the exterior paint. Over time, outside elements such as weather take a toll on the condition of your exterior. If you plan to paint the exterior, it is important to properly prepare the outside surface by cleaning the existing paint. A thorough cleaning can give the appearance that you have already repainted the exterior without actually having done so. Check the weather report ahead of time to choose a day to clean that is sunny with minimal wind.

Exterior Paint Cleaning

Step 1

Cover light fixtures and plants that are close to the exterior with plastic bags.

Step 2

Connect a garden hose to an outside water faucet.

Step 3

Connect a brush attachment to an extension pole, and attach the extension pole to the garden hose.

Step 4

Combine 1/4 cup of trisodium phosphate (TSP) with 1 gallon of water for heavy duty cleaning.

Step 5

Apply the TSP mixture onto the brush, and turn on the garden hose. Open the shutoff valve on the extension pole if applicable.

Step 6

Start at the bottom of the exterior, and work your way up one section at a time. If you start at the top of the wall, the dirty water will streak; but if the dirty water runs down a clean surface, it will not streak.

Step 7

Rinse the mixture off the exterior in a downward motion.

Mildew Cleaning

Step 1

Mix one part bleach to three parts water to remove mildew stains.

Step 2

Apply the bleach mixture to the mildew stains, and leave it for 20 minutes.

Step 3

Rinse the exterior thoroughly.


  • Wear gloves and eye protection when working with chemicals.
  • Read and follow all manufacturer warnings and instructions.
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