Is Cement Board Mold Resistant? What You Need to Know

Mold is a type of fungus that can grow on any surface, including cement board. It can cause a number of health problems, including allergies, asthma, and respiratory infections. Mold growth can also damage your home, leading to expensive repairs.

Cement board is a popular building material that is known for its durability and moisture resistance. However, it is not completely immune to mold growth. Under certain conditions, mold can grow on cement board, especially if it is not properly installed or maintained.

Is Cement Board Mold Resistant?

Are Cement Boards Vulnerable to Mold?

Mold, that uninvited guests in our homes, can cause not just an eyesore but also health issues. It creeps into our living spaces, often unnoticed, and wreaks havoc. So, how do cement boards fare in the battle against mold? Well, it’s a bit of a mixed bag, and we’ll explore why.

Cement boards are widely known for their exceptional resistance to moisture, fire, and termites. They are constructed with a combination of cement and reinforcing fibers, making them a stalwart option for various applications, primarily as an underlayment for tiles or siding material. However, before we label them as unbeatable mold busters, let’s understand the science behind mold growth.

How Mold Grows

Before discussing the mold-resistant qualities of cement boards, it’s crucial to understand the root cause of mold growth. Mold spores, which are practically everywhere, are like tiny, invisible ninjas. They need a few things to hatch their devious plan: moisture, warmth, and a food source.

While cement boards are indeed highly resistant to moisture, they can’t do much about the temperature in your home, which is usually quite cozy. And, when it comes to a food source, well, mold can feed on organic matter such as wood and drywall, but not on cement. So, you’d think cement boards are in the clear, right? Not so fast!

Which Things Make Cement Board Mold Resistant?

So, why are cement boards somewhat formidable against mold? Let’s break it down:

No Yummy Food

Mold is a type of fungus that needs organic matter to survive. Organic matter is anything that was once alive, such as plants, animals, and their waste products. Cement board is made from inorganic materials, such as cement, sand, and water. Inorganic materials are not made from living things, so they do not provide a food source for mold.

Moisture Barrier

The cement board is also designed to be moisture-resistant. This means that it will not absorb water easily. Mold needs moisture to grow, so if the cement board is wet, it is less likely to support mold growth.

No Paper Trail

Drywall, which is a common building material made from gypsum board, is often covered with paper facing. Paper is an organic material that mold can feed on. Cement board, on the other hand, does not contain any paper components. This makes cement boards less susceptible to mold growth than drywall.

Good Ventilation

Mold thrives in dark, humid environments. Proper ventilation in your home can help to reduce moisture and humidity levels, which can make it less likely for mold to grow. Cement board is often installed in areas where ventilation is a priority, such as bathrooms and kitchens.

Tiling Over the Top

When cement board is used as a substrate for tiles, it is often sealed with waterproof materials. This creates an additional barrier against moisture and mold. This makes it even more difficult for mold to grow on cement boards.

Overall, cement board is a mold-resistant building material that can help to protect your home from mold damage. It is especially well-suited for use in areas where moisture is present, such as bathrooms and kitchens.

Are Cement Boards Totally Immune against Mold?

While cement boards offer substantial resistance to mold, they are not entirely immune. If conditions are just right (or should we say wrong), mold can still find a way. Here are some factors to consider:

Cracks and Gaps

A cement board is a durable material, but it can still crack or develop gaps over time. If this happens, moisture and mold spores can infiltrate the material and start growing. It is important to inspect your cement board regularly for cracks and gaps and to repair them immediately if you find any.

Leaky Leaks

Even if your cement board is properly installed and maintained, it is still susceptible to mold growth if it gets wet. If there is a leak from somewhere else in your home, such as plumbing or the roof, and your cement board gets wet, mold can take hold. It is important to identify and repair any leaks in your home as soon as possible.

Neglected Maintenance

Even if your cement board is properly installed and free of leaks, it is still important to clean and maintain it regularly. If you neglect to clean your cement board, dirt, dust, and other organic matter can accumulate on the surface. This can provide a food source for mold and allow it to grow.

However, if you have any confusion or if you are willing to add extra protective measures against mold growth, then you can use tri-sodium phosphate spray. You will just need to spray the liquid all over the cement board and it will create a barrier against mold.

So, Should You Use Cement Boards?

Absolutely! When used correctly and in the right conditions, cement boards are an excellent choice for your construction and renovation projects. Their resistance to moisture and mold makes them a top pick for areas prone to dampness, such as bathrooms and kitchens. But remember, even superheroes have their limits, so stay vigilant and proactive in the fight against mold.

Get ready to use mold-resistant cement boards for your project. Keep mold at bay during your construction or renovation.


In a world where mold seeks to infiltrate our living spaces, cement boards emerge as formidable contenders in the battle against this pesky invader. Their resistance to moisture and lack of organic matter make them a strong defense. However, they are not entirely immune, and proper installation, maintenance, and vigilance are essential. So, go ahead, embrace cement boards for your projects, and enjoy a mold-resistant environment.

We hope this article has armed you with the information you need to make an informed decision. If you have more questions or need further assistance, don’t hesitate to reach out. Happy renovating!

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