How to Clean Steel Siding

Kendra Dahlstrom

Steel siding requires little maintenance. Over time, however, oxidation and corrosion can occur. While these problems happen to virtually all steel siding after time, there is something you can do to delay it.

You may have to rent a few items, but washing steel siding every six months to a year can do wonders to delay oxidation and return the siding back to new. Cleaning steel siding can be different from cleaning vinyl or wood siding. Use these steps as a guide to teach you how to clean your steel siding on your home or building.

  1. Cut the power to outdoor lights next to your steel siding. You will be working with high pressured water, so you don't want any hot electrical wires. Simply flip the breaker switch to the outdoor lights.

  2. Mix 6 gallons of water with 1/3 cup laundry detergent. This will be the cleaning solution. Go ahead and dump it into the power washer tank. It is not time to use the power washer yet, but this way you are prepared.

  3. Attach a soft car washing brush to the end of a garden hose and thoroughly scrub the outside of the steel siding. This will remove all of the caked on grime and dirt that has adhered itself to the siding.

  4. Use a pressure washer to get to all the cracks and crevices you could not reach with the brush. Be sure to use the power washer on the lowest setting it has. Although you want pressure to clean dirt and grime, you don't want too much pressure. Too much water pressure could dent the steel siding.

  5. Rinse the cleaning solution right away with a garden hose. Do not wait until the cleaning solution has dried as this could damage the paint over time. Rinse the siding thoroughly. Then, simply let your home or building dry in the sun. There is no reason to manually dry it off.


Always start at the top of the steel siding and wash your way down. This will prevent dirt streaking the finish. Make sure you shut all of the windows before using the power washer. Failure to do so could lead to a very wet interior.


Don't let the cleaning solution drip on flowers and plants. Make sure to cover them with plastic before washing steel siding.