How To Clean Your Siding: Vinyl, Cedar, Wood, and Fiber Cement

Cedar lap siding installation and cleaning

Thinking about renting a power washer and blasting the side of your house in an effort to clean your siding? Think again.

While a power washer might be appropriate in some applications, the way you approach cleaning your siding depends on what it’s made of. Vinyl, cedar, wood and fiber cement materials deserve customized cleaning solutions, so let’s look at a few options.


Vinyl siding is hugely popular for a number of reasons. It’s cost effective, comes in many colors, shapes and sizes, and is fairly easy to maintain. However, if your vinyl siding is beginning to look grimy, it’s time to knock down the dirt. The Vinyl Siding Institute advises using a soft cloth or soft-bristle brush. These will prevent the grim from streaking as you wipe it away.

If your vinyl siding has mildew and/or mold, you’ll need to use a cleaning solution such as a mixture of water and white vinegar (70 percent water to 30 percent vinegar). But remember, what you put on your siding will end up on the ground, so be sure the chemical you’re using doesn’t kill your landscaping. For instance, if you want to use oxygen bleach, mix one gallon of water with one cup of the bleach.


Nothing beats the look of cedar siding. However, it can become the victim of mildew and mold just as vinyl siding can. One method of cleaning it is to use a five-gallon bucket filled with water and add the appropriate amount of granular oxygen bleach. Manufacturers have different recommendations on the ratio of water to bleach, so follow the directions on the label.

Saturate the cedar siding and scrub it with a brush. You’ll need to repeat this process until the cedar is clean.

If your cedar has an oil-based stain, it can actually feed the mold. Experts recommend NOT using a pressure washer as this can force water between the seams and cause moisture to penetrate to areas of your home that you want to remain dry. Oxygen bleach is a good chemical to use on this as well. If you’re nervous about the bleach damaging your siding, do a test scrub on a small area, let it dry and inspect the area.


There are some products out there that offer a gentler approach to cleaning your siding than a pressure washer can offer, yet also allow you to cover greater areas in less time than cleaning by hand. For instance, if you’re cleaning your wood siding and don’t want to put in so much elbow grease, consider something like the PivotPro. It’s a product that utilizes a direct stream of water from your garden hose that runs through a reservoir of your chemical mixture. A brush at the end of the extending pole allows you to scrub away the grime.

Again, using oxygen bleach offers excellent results, just make sure you’re not using chlorine bleach, which can negatively impact the color of your siding and kill the landscaping it comes in contact with.

An alternative to oxygen bleach is trisodium phosphate, which should be mixed at a ratio of a half-cup of phosphate to every gallon of water. Finally, make sure your scrubbing brush has soft bristles.

Fiber Cement

Fortunately, fiber cement siding is durable and is replaced less often than other types of siding material. It will, however, require minimal upkeep. Dirt, dust, mold and debris need to be cleaned as soon as you notice it if you want to get the longest life out of your fiber cement siding. Some of the top siding manufacturers, such as James Hardie, offer cleaning instructions that you should follow.

James Hardie’s website recommends using a soft all paint brush, horsehair brush, chip brush or a special siding brush. For cleaning dirt and chalk, they recommend using a soft cloth or soft bristle brush and water from a garden hose. Wet the cloth or brush as well as the siding, scrub and rinse until clean.

For oil, grease and other contaminants, they recommend a soft cloth, garden hose, and a mild liquid dishwashing soap. Stay away from harsh cleaning chemicals. Frequently rinse your cloth as you clean the siding.

For mold and mildew, James Hardie recommends using a soft cloth or soft sponge, garden hose and a solution of trusted mildew cleaner, such as those made by Jomax and Armor. Follow the instructions on your mildew cleaner, and make sure to rinse the all cleaner off the siding.

Need more tips on cleaning your siding or do you want to replace your siding? Contact us today at VIS Exterior at (630) 230-8533.