How to Clean James Hardie Fiber Cement Siding

Like any outdoor product, even the ultra-durable James Hardie fiber cement siding needs a little TLC once in a while. Dirt and filth from bird droppings, dust, and pollen can accumulate on your exterior surface, diminishing the look of your siding and your house.

James Hardie siding shouldn’t need cleaning very often. It is resistant to mold, mildew, and fading, but it can get dirty over time like all things. Luckily, it’s extremely easy to clean.  However, before you start cleaning, you should understand there’s a right way and a wrong way! So, be sure to use these cleaning tips from Opal Enterprises.

A close-up of fiber cement siding. Proper care and maintenance can help you preserve your James Hardie fiber cement siding for years.

Put Safety First When Cleaning Your Fiber Cement Siding

Like any at-home project, it’s essential to make sure you’re operating as safely as possible. Wear suitable safety apparel, including:

• Comfortable clothes
• Closed-toe shoes
• Personal protective equipment (PPE) including thick gloves, goggles to protect your eyes from soap and debris, and a face mask to filter chemical fumes or dust

Depending on what’s being scrubbed off your siding, breathing in debris or chemicals splashing onto your skin can be hazardous. Be sure to take extra precautions when dealing with mold or mildew.

Other safety measures you should take include:

• Making sure children or pets are well away from your work area
• Moving outdoor furniture or other objects 
• Having your friend or spouse hold your ladder when you’re working on it 

Safeguard Your Landscaping and Home Interior

The next thing you should do is inspect your fiber cement siding. Walk around your home and check for damage by natural hazards or falling branches. Be sure to close your doors and shut your windows to prevent soap and water from entering your home. 

In addition to protecting yourself and your family, make sure to cover your plants, potted flowers, and landscaping from debris or soap splatter. Using a thin plastic tarp should work fine. This is especially important if you plan to power wash or use stronger cleansers.

Additionally, disconnect power cords from your home, turn off light switches, and protect your light fixtures with duct tape and plastic.

Check the Weather Before Cleaning

You want to choose a day that isn’t raining but also has very little direct sunlight. Try to time your cleaning on a day that’s overcast or cloudy. Otherwise, direct sun can dry the water on your siding quickly and unevenly.

A scrub brush kit with a long pole and attachments. Purchase an extension pole to make cleaning your James Hardie fiber cement siding easier.

Questions? Call 847-380-8868 in Des Plaines and 630-355-6557 in Naperville

Begin Cleaning Using a Soap and Soft Brush Method

Before you start, be sure to read any instructions outlined in your James Hardie maintenance guides, which can be found on Opal’s Care & Maintenance page.

After familiarizing yourself with your product’s specific precautions, it’s time to assemble your equipment. One of the most crucial things to keep in mind is never to use an abrasive sponge or a hard-bristled brush. Doing so could damage your siding or its finish.

To wash your James Hardie fiber cement siding properly and safely, follow these cleaning methods for the best results:

1. Choose a mild biodegradable soap like dish soap.
2. Use a soft brush or cloth.
3. Reel out the garden hose.

To make the job even easier, many hardware stores sell extension poles with brushes or sponges. When choosing a soap, avoid products containing harsh chemicals that could damage your siding. 

A little goes a long way. Now you can clean away the dirt and lightly scrub the siding. Start from the top and clean with the direction of the siding. Use a side-to-side motion when cleaning horizontal planks. Be sure to thoroughly rinse it free of any soap residue.

How to Treat Mold and Mildew

Unfortunately, many homes are targets for mold and mildew buildup. These fungi are similar and breed in the same locale, so when you see one, you often see the other. 

When dealing with mold and mildew buildup, you’ll need your soft sponge or cloth and your water hose, plus a mild cleanser that’s safe for fiber cement siding. James Hardie recommends Mildew Check®, Jomax®, or Mold Armor®.

Follow the product recommendations to avoid injuring yourself or damaging your siding. Be sure to avoid coming into contact with the solution and wear your PPEs. Since many mildew and mold cleaners are sold in concentrated form, be sure to dilute your cleaner with water.

Use your soft sponge or cloth and lightly scrub the mold or mildew with the cleanser. Once it’s clean again, use your water hose to thoroughly rinse the area with water.

A man power washing a house. Use caution when using a power washer to clean your fiber cement siding from James Hardie. The powerful spray can cause considerable damage.

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Can You Power Wash Fiber Cement Siding?

If you have a large area and decide to clean it using a power washer, you should take extreme caution. If done incorrectly, it can damage your siding and void your James Hardie warranty. Hire a professional if you’re inexperienced using a power washer. If you feel confident in your abilities:

• Use a low-pressure spray of less than 1500 psi
• Utilize wide fan tips
• Don’t use your power washer any closer than six feet

If there isn’t much dirt or debris on your James Hardie fiber cement siding, try using your soap, brush, and garden hose before using a power washer.

Before using a power washer for the first time, it is a good idea to consult with your siding contractor. They can further advise on cleaning the siding without causing any damage.

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Follow Opal’s Tips for Cleaning Your James Hardie Siding

Follow Opal Enterprise’s tips for cleaning your James Hardie fiber cement siding to prolong the product’s life and beauty. Always work in small areas from top to bottom to avoid streaking in already clean areas. Be sure to keep the area wet with water and always wash in the direction of the plank.

For any questions about your James Hardie siding or any products we install, call or contact Opal Enterprises in Des Plaines and Naperville by filling out our online form.

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