How to Clean Aluminum Siding

With spring just around the corner and the weather looking up for parts of the country, it is time to think about cleaning up the outside of your house, office building, trailer, or wherever it is that is constructed of aluminum siding.

I recently took to cleaning the outside of my house which has painted-white aluminum siding and have found a few methods that worked wonders on clearing the hard water, grime, rust stains, etc.

Prepping the home to clean aluminum siding:

First you need to prep the area around where you plan to clean. Make sure windows are all closed, any rugs, furniture, décor, etc., are moved out of the way, and any delicate plants are covered or, if in a pot, moved to a safer location for the time being.

You’ll also want to make sure you wear clothes you don’t mind getting dirty. It is a very dirty job, trust me on this one.

Method 1: Power Washer

While I was doing research on the best methods to clean aluminum siding, use of a power washer seemed to be a common method.

When using a power washer, which you can typically rent or purchase from a local hardware store, be sure to use it on a lower setting to ensure you don’t dent or damage the siding.

The power washer, I found, is a great first step, but not necessarily the best way to remove rust stains. It got rid of the dirt and some of the hard water stains, but I still had to do more manual labor to remove the orange rust that was the real eye sore on my white siding.

Method 2: Detergent and Water Solution

This method removed a majority of the orange rust and all of the hard water stains.

What you will need:

  • Laundry detergent
  • Warm water
  • Porous sponge or soft bristled brush (you can also use a push broom for hard to reach areas)
  • Old rags
  • Bucket (I just used a small 2 gallon bucket as it is all I have)
  • Hose

Cleaning process:

  1. Fill bucket with warm water and ¼ cup of laundry detergent.
  2. Start at the top and work your way down the siding. I did it in about five-foot sections. You might find that you just need the soft side of a sponge for the top half of the siding, but then need the porous side or bristle brush the more you work your way down.
  3. Work in a circular motion to ensure you get into the groves. This also varies the motion on the siding which will help to ensure you don’t start removing the paint. Going side to side along the grain may cause the paint to wear.
  4. After you have finished the section you have two options. 1) You can either move on to the next section if you were able to remove all the grime, or 2) you can go over what you just scrubbed with a rag and clean water to wipe the excess off.
  5. Once you have finished a whole side you can rinse the detergent and water solution off with a hose or power washer (on a low setting).

After doing this method, my house was almost sparkly white (I also have found that using some sort of tile cleaner with warm water works as well). However, I had a few stubborn areas I just couldn’t scrub off. So… on to method three.

Method 3: Paint

If both the above methods still don’t clean the siding, just repaint the siding. If you plan to do any painting be sure to get paint meant for outdoor and metal material use. Your local hardware store paint specialist should be able to point you in the right direction and give you instructions on how to prep, paint, and set it.