Calcium Silicate (CS) board offers good moisture resistance, making it a superior choice compared to standard gypsum board (plasterboard) for damp environments. However, it’s important to understand the nuances of this resistance
Key Points on Moisture Performance
- Dimensional Stability: One of the main advantages of CS board is its excellent dimensional stability. Unlike materials that use paper or organic fillers, CS boards are primarily composed of non-organic, stable compounds. This means they are highly resistant to swelling, warping, or rotting when exposed to high humidity and temperature changes.
- Water Absorption: While highly resistant to humidity, CS boards are not completely waterproof. They will absorb some water if directly and continuously exposed to standing or flowing water (like inside a shower enclosure). In fact, some sources note they can absorb a significant amount of water by weight.
- Non-Combustible and Non-Nutrient: Because the boards are inorganic and do not contain organic compounds, they do not serve as a food source for mold or mildew. This is a major benefit for wet areas.
Usage in High-Humidity Areas (Bathrooms and Kitchens)
Yes, Calcium Silicate boards are highly suitable for use in bathrooms and kitchens (ceilings and walls) and are often the preferred choice over standard gypsum board in these areas.
| Application Area | Suitability | Important Considerations |
| Kitchens | Excellent. | Ideal for fire safety and resisting steam/humidity from cooking. |
| Bathroom Ceilings/Walls | Excellent. | Handles high humidity and condensation without warping or supporting mold growth. |
| Inside Shower Enclosures | Good, with required precautions. | Must be completely waterproofed with a liquid-applied membrane or appropriate tile adhesive and grout system before tiling. They are generally used as a substrate, not the final water barrier. |
CS boards are an excellent, durable, and reliable choice for most high-humidity areas due to their mold resistance and stability. For areas with direct, continuous water contact (like a shower wall), they perform well as a substrate but require proper waterproof sealing to protect the structure behind the board
OCT
2025