1. Cement Base, Fiber Reinforcement
Fiber cement board is primarily made of cement and sand, inheriting cement's natural strength and compressive capacity.
But cement alone is brittle and prone to cracking. That's where the "fiber" comes in. These fibers (usually cellulose or other specialized types) act like the steel mesh in reinforced concrete, interwoven throughout the board. They serve as both a "skeleton" and "ligaments," holding the cement together. This combination makes the board not only strong but also resilient and impact-resistant. A hard kick won't pierce it like drywall, nor will it shatter like plain cement board.
2. High-Pressure Curing for Extreme Density
These boards don't dry under typical conditions; they get made under extreme temperature and pressure. This is essential, similar to forging steel, where repeated hammering creates a stronger piece of metal.
The raw materials are subjected to a high amount of pressure, which compresses the materials together, removing air and moisture in the process, to create a very dense and compact board. So what does a 'high density' board mean? It means it is a stronger, heavier board. You can feel it just picking one up; it is way heavier than a comparable coated gypsum board. This 'heaviness' is the most tactile indication of the product's strength. High-density boards also increase resistance to deformation and will not warp as easily as regular boards.
3. Weather Resistance
Fiber cement board is highly durable and naturally resistant to water, fire, insects, and mold.
Water-resistant: With a cement core, it resists water damage (unless exposed for very long periods). It can be used in bathrooms, toilets, exterior walls, and damp basements without issue. Unlike gypsum boards, it won't fail when exposed to moisture.
Fire-resistant: Cement and sand do not burn. They are inorganic, Class A non-combustible materials. The product (board) will not burn, nor give off toxic gases when exposed to fire. This will help curb flames and will give you extra time to escape.
Termite- and mold-resistant: Insects do not eat cement, and mold cannot spread in such a dense, inorganic material. Therefore, fiber cement boards can be installed when there is a greater risk for termites or within conditions of high humidity.