How to Clean a James Hardie Plank

James Hardie planks are made from fiber-cement with a laminate top.

The material is durable and weatherproof. The laminate top provides a smooth surface that takes little effort to prep before painting. When you are ready to paint your siding, you will need to clean it first, and then it is recommended that the siding be washed at least twice a year. Cleaning your James Hardie planks may take time, depending on the size of your home, but it does not require much effort.

Hook up your pressure washer up to a hose connected to the spigot on the side of your house.

Put on protective eyewear.

Turn on the power to the pressure washer. If you have an electric pressure washer, you will need to run an extension cord from an outlet to your pressure washer.

Adjust the pressure washer to the lowest setting, usually about 1,500 PSI.

Aim the trigger wand toward the highest part of the plank and begin to spray the area.

Spray the planks in a downward motion.

Continue to spray until you have cleaned all of the planks.

Things You Will Need

  • Hose
  • Pressure washer
  • Goggles


  • Depending on the level of cleaning required, you may be able to use a hose with a high-powered spray nozzle instead of a pressure washer.


  • Do not use high pressure while cleaning the planks as it may damage the siding.

About the Author

Based in Columbus, Ga., Ashley Hay has been covering animal health and wellness since 2004, and arts and entertainment since 2008. She holds a Bachelors of Arts in psychology from the University of Central Florida.