How to Clean Fiber Cement Siding

How to Clean Fiber Cement Siding

how to clean fiber cement siding on your homeEXOVATIONS is proud to be a James Hardie Preferred Remodeler. Along with installing beautiful siding, we also want to help you maintain your siding correctly. Fiber cement siding is designed to be extremely durable and need replacement less often than other siding materials. With that being said, it does require minimal upkeep to get the most of the product. With any type siding, prevention is always key to making it last for years to come.

(Not sure what kind of siding is on your home? See our blog post "How Can I Tell What Kind of Siding is On My Home?")

So how and when should you clean fiber cement siding? The amount of maintenance needed will depend on the geographic location of your home. It is always recommended to clean your siding, as needed, to remove dirt, dust, mold, debris and build up that occurs over time.

Before completion of any siding repair or siding replacement project, EXOVATIONS removes any dust from the installation and construction process. From the beginning, you can expect to have a spectacular looking product when siding is installed by EXOVATIONS.

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As always, it is important to use appropriate safety apparel during cleaning. Always wear protective eyewear, gloves and respiratory protection. Depending on what debris is being cleaned from the siding, breathing in particles or debris coming in contact with your skin or eyes can be very dangerous. Always err on the side of caution when protecting yourself from dust, mold or mildew.

As well as protecting yourself during the cleaning process, be sure to cover any landscaping or plants. Using a thin poly or tarp will work fine. Just make sure your perennials and annuals are well protected from any spray or splatter of debris.

James Hardie recommends to first read any instructions outlined in your specific James Hardie product literature. After you've read up on the specific precautions to take with your product, it's time to gather your tools. One of the most important things to remember is to never use a hard or abrasive brush. Using an abrasive scrub brush or sponge could damage the finish or siding.

Removing construction, cutting debris, dirt or chalk:
Recommended tools for removing any type of construction or cutting debris, dirt and chalk can be easily accomplished with an this method and with the following tools and solution.

  • Soft cloth,
  • Soft paint brush,
  • Chip brush,
  • Horsehair brush or
  • Siding brush
  • Water hose

In this case, we'll only be using water as our solution to clean the siding. Simply brush the siding with the soft brush to free the surface of the culprit you're trying to clean. Then, rinse with the garden hose. If using a soft cloth to remove the debris, with a wet cloth, wipe the siding clean and rinse with clean water. Change the cloth or rinse it often if there a lot of debris builds up on the rag.

Removing oil, grease or natural contaminants:
The recommended tools for removing any type of oil, grease or other non-chemical debris combined with a simple solution creates for an even simpler cleaning process. All you need is the following:

  • Soft cloth,
  • Water hose

We'll be using a simple solution of a mild liquid dishwashing soap like Dawn®, Ivory® or Joy®. Just like you should never use an abrasive brush, never use any harsh chemicals to clean your siding. To clean your siding, wet your soft cloth with soapy water. Apply to the siding and use your water hose to rinse the area.

Removing mold and mildew:
The last contaminant you may need to remove from your siding is the dreaded mold and mildew. Mold and mildew thrive in moist, humid environments. Unfortunately your home will always be a target for mold and mildew. These similar fungi usually breed together so if you see one, you'll more than likely see the other.

To tackle these fungi cousins, we'll need the following tools:

  • Soft cloth or
  • Soft sponge,
  • Water hose

In this case, we'll use something a little more pungent than water and liquid dish soap. Visit your local home improvement store and purchase a fiber cement siding safe mildew cleaner. James Hardie recommends using mildew cleaner like Jomax®, Mildew Check® or Mold Armor®. Mix the mildew cleaner with water as recommended on the mildew cleaner instructions. Strong mildew cleaners are often in concentrate form, so make sure to follow the directions correctly as not to damage your siding or yourself. It is extremely important to wear protective apparel when using chemicals and when in contact with mold or mildew. Lightly scrub the siding area covered with mildew with your sponge or cloth. After it's sparkling and new again, rinse with the water hose.

Follow these recommended cleaning methods and the following pointers for any type debris removal. Always start work with small areas at a time and work your way from top to bottom. This will prevent streaking on already clean areas. When using your brush, cloth or sponge, always clean in the direction of the plank. Never allow the solution to dry on the siding; always keep the area wet with a water hose. If using a pressure washer, be aware high pressure water can damage the fiber cement. If you must use a pressure washer, always use a low pressure water spray with a wide tip, kept at a minimum of 6 feet from the siding and at a pressure under 1500 psi.

You can always ensure EXOVATIONS will do a fantastic job for your home. Contact us if you're siding is beyond washing and you're ready for new James Hardie fiber cement siding.


Our team is dedicated to providing stress-free home exterior services on time and on budget. As a Georgia-based company, we have worked for years throughout these cities and their surrounding areas, building a reputation as a trustworthy remodeling company that customers can rely on. Our friendly staff is here to provide suggestions and resources to ensure the job gets done in the most efficient manner, so you can save time and energy when tackling your next project.

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