Product Overview
Calcium silicate board is manufactured from lime, silica sand, and reinforcing fibers, cured under high-pressure steam (autoclaving at 120–180°C). This process creates a crystalline tobermorite structure that gives the board its strength and stability.
Compared to fiber cement board, calcium silicate board offers better dimensional stability but higher water absorption. This makes it ideal for interior applications and fire-rated systems, but less suitable for direct exterior exposure without waterproofing.
Technical Specifications
| Parameter | Value | Standard |
|---|---|---|
| Thickness | 6mm, 8mm, 9mm, 10mm, 12mm, 15mm, 18mm, 20mm | JC/T 564.1 |
| Standard Size | 1220mm × 2440mm (4' × 8') | — |
| Density | 1.2–1.5 g/cm³ | GB/T 7019-2024 |
| Flexural Strength | ≥ 7 MPa (saturated) | GB/T 7019-2024 |
| Water Absorption | 25–35% | GB/T 7019-2024 |
| Moisture Expansion | ≤ 0.15% | GB/T 7019-2024 |
| Fire Classification | A1 (non-combustible) | GB 8624 / EN 13501-1 |
| Thermal Conductivity | ≤ 0.25 W/(m·K) | GB/T 10294 |
Applications
| Application | Recommended Thickness | Notes |
|---|---|---|
| Interior partition wall | 8–12mm | Paired with light-gauge steel framing. Standard 600mm stud spacing. |
| Suspended ceiling | 6–9mm | Note: 8mm+ boards are heavier than gypsum — verify framing load capacity. |
| Fire-rated wall lining | 12–15mm | Used in fire-rated assemblies. System rating depends on full construction, not just board. |
| Wet area backing (with waterproofing) | 10–12mm | Must be combined with waterproof coating. Not inherently waterproof. |
| Flooring substrate | 15–20mm | High-density grade, for tile or vinyl flooring backing. |
Calcium Silicate vs Fiber Cement: Quick Comparison
| Calcium Silicate Board | Fiber Cement Board | |
|---|---|---|
| Binder | Lime + silica | Portland cement |
| Curing | Autoclaved (steam pressure) | Air-cured or autoclaved |
| Water absorption | 25–35% | 12–20% (exterior); ≤30% (interior) |
| Dimensional stability | Excellent | Good |
| Exterior use | Not recommended without waterproofing | Yes, with proper specification |
| Wet areas | With waterproofing | Yes |
| Price (relative) | Lower | Higher |
What to Check Before Ordering
- Non-asbestos certification — same requirement as fiber cement. XRD report required.
- Density consistency — calcium silicate boards are prone to density variation between batches. Demand tolerance data.
- Edge integrity — poorly pressed edges crumble during cutting. Inspect samples for clean, sharp edges.
- Surface smoothness — for direct painting or wallpaper, the board surface should require minimal joint compound.
- Alkali resistance — if the board will receive paint or tiles, confirm compatibility with alkaline substrates (pH 10–12).
Technical parameters are based on JC/T 564.1-2018 and GB/T 7019-2024. Actual specifications should be confirmed against current standards and project-specific requirements.