Pressure Washing Aluminum Siding

How to Correctly Pressure Wash Aluminum Siding

If you’re someone who has aluminum siding installed on their home or you’ve passed a house that has this type of siding, and it hasn’t been cleaned in months or years, you’ll likely see a large amount of grime.

The grime may not hurt the siding, but it can drive your home’s curb appeal down. Luckily for you, aluminum siding is relatively easy to clean with the correct tools.

Pressure Washing Aluminum Siding


  1. Spray a small part of the siding with a hose.
  2. Apply the cleaning solution that you picked out and allow it to sit.
  3. Get a siding brush and scrub any debris or stains from the siding.
  4. Rinse the aluminum siding using the pressure washer, working from top to bottom.
  5. Repeat the steps with all the siding sections until you finish.

Even though it can be easy enough to pressure wash your aluminum siding, there are a few things you should do to make the job easier, quicker, and more efficient without damaging the siding.

We’ll list the tools you need and the steps to follow to complete this project below.

Steps to Take to Pressure Wash Aluminum Siding

When you get ready to tackle this project and pressure wash your aluminum siding, there are specific steps to keep in mind. It’s important to note that this process will take time, and rushing it can cause damage or half-clean siding.

Step One

Even though this step is technically optional, it’s not a good idea to skip putting on the protective gear and taking steps to protect the landscape.

Put protective sheets of plastic over the landscape by your aluminum siding, so you don’t accidentally damage the bedding or plants.

Also, consider putting on protective goggles, so you don’t get flying soap or debris in your eyes.

Step Two

Pick the area where you want to start working and map out small sections to take on at a time, working top to bottom. Don’t attempt to spray the entire wall in one go.

Even though this may seem like the more efficient step to take, the water will dry out before you can give the whole area a decent scrub. You can spray the siding with a pressure washer or a garden hose.

Step Three

Apply the cleaner of your choice to your aluminum siding. You can apply this using the pressure washer, garden sprayer, or spray bottle.

Allow the cleaner to sit on your aluminum siding for however long the product recommends to get the most thorough clean.

Step Four

Once the cleaner finishes sitting and working on the siding, you want to get your long-handled scrub brush and start scrubbing at the siding.

Again, you’ll work in sections from top to bottom, and be sure to pay closer attention to any very dirty or heavily stained areas.

Step Five

Get your pressure washer and rinse the cleaning solution off of the siding, and you want to make sure to only spray in a downward direction with the water jet.

If you go under the siding with your water, it could get trapped and cause problems with mold or mildew.

You also want to be very careful around any doors or windows because the spray could do damage or break the glass.

Step Six

Let your cleaned area dry thoroughly and check to see if you’re satisfied with how your aluminum siding looks. If you still see dirt or grime, you may want to repeat the steps we listed out.

For siding that has years of buildup, you may have to clean them several times to remove everything.


  • When you use a pressure washer on your aluminum siding, you want to set the nozzle to at least 15-degrees because anything lower will damage the siding. The most beneficial nozzles to use are between 25 to 40-degrees because this will give you the pressure you need to strip away the dirt while widening the spray area. The higher the degree nozzle you use, the lower the pressure will be. You also want to make a point to stay 10 to 12-inches away from your home and use a downward motion with the sprayer.

Power Washing Aluminum Siding Challenges

Even though using a pressure washer is the go-to method of cleaning aluminum siding for many homeowners, it does have some challenges. Let’s touch on the biggest ones below.

Damage Potential

Using a pressure washer can be far too harsh on some aluminum siding or other sidings like stucco, brick, or vinyl.

Too much pressure will do much more harm than good, and it can damage the material or force the siding away from your home’s structure.

This is a concern you have; it’s a good idea to consider soft washing instead.

Landscape Damage

Bleaching agents or chemical-based cleaning agents can kill your flowers, grass, and bushes.

You can protect them by covering them up with sheets of plastic or a tarp before you start pressure washing your aluminum siding.

You could also pick out a biodegradable, water-based cleaning solution that is more landscape-friendly.

Siding Dries Out Quickly

When you use a detergent to clean your siding, your surface must stay wet to make it effective.

If you’re trying to clean the whole side of your house, it’s best to work in smaller sections. Divide it into areas that are four to five feet wide to ensure you have enough time to apply the cleaner before the siding dries out.

Tough Stains Won’t Wash Away

Cleaning the outside of your home can be a very dirty job, and you could easily end up with dark patches or stains on your aluminum siding after you finish the cleaning steps we outlined.

Stains can form on the lip of your siding and be very hard to remove, so you may have to scrub them with a soft-bristle brush that you can attach to your pressure washer’s extendable wand.

You may also have to repeat the cleaning steps more than once.

Mildew and Mold Survive the Cleaning

For mold and mildew growth, it may be necessary to apply a bleach mixture as the main cleaner. There are also specialized products you can try that come formulated especially for siding.

Apply it after you finish the cleaning process we outlined, and make sure to rinse the siding when you finish thoroughly.

Resolve These Problems with Soft Washing

You can avoid a lot of these challenges by opting to soft wash your aluminum siding instead of using higher pressure.

This is a much more delicate spray cleaning process that works well on a host of exterior housing materials like stucco, stone, brick, vinyl siding, painted wood, and aluminum.

Bottom Line

Pressure washing your aluminum siding can be fairly straightforward and inexpensive as a way to maintain your home’s appearance and boost your curb appeal.

You should only start this project when you have the time and equipment ready to devote to it, and you want to make a point to clean your siding at least once a year for the best results.

Aim to wash your siding in the warmer months and look forward to a sparkling clean finish when you get done.

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