Product comparison
Fiber Cement Board vs Gypsum Board
For exterior facades, wet rooms, and fire-rated walls — technical comparison of fiber cement board and gypsum (plasterboard) for European construction.
Exterior use
FCB yes · Gypsum no
Wet rooms
FCB fully wet · Gypsum splash only
Fire (assembly)
FCB E120/EI90/EW120
Comparison table
| Property | Gypsum Board | Fiber Cement (Terasun TSM) |
|---|---|---|
| Exterior use | Not suitable (dissolves when wet) | ✓Yes — all climates (Category A) |
| Wet room use | MR grade with protection only | ✓Yes — fully waterproof behind tiles |
| Fire class | A2 (standard), A1 (Type F) | ✓A1 |
| Moisture resistance | MR grade resists splash — not immersion | ✓EN 12467 Category A — immersion stable |
| Weight (12–13 mm) | ~10 kg/m² | 9.96 kg/m² |
| Screw holding | Good (interior) | Good — use pre-drilled holes |
| Paintable | Yes | Yes |
| Tileable | MR grade only (interior) | ✓Yes — interior and exterior |
| CE standard | EN 520 / EN 15283 | EN 12467 — CE 1023-CPR-1565 P |
| ETA | — | ✓ETA 24/0895 |
| EPD | Available for major brands | EPD-IES-0018268 |
| Fire assembly rating | Up to EI 60–90 (tested systems) | ✓E120 / EI90 / EW120 (FIRES-CR-284-25) |
| Ease of cutting | Score-and-snap easy | Circular saw or angle grinder |
| Material cost | Lower | Higher |
The core difference: water
Gypsum (calcium sulphate dihydrate) is water-soluble. When exposed to sustained moisture, gypsum board loses structural integrity, swells, and eventually dissolves. Moisture-resistant (MR) gypsum board delays this with water-repellent additives, but the fundamental chemistry does not change.
Fiber cement board is an inorganic product. Portland cement, once set, does not dissolve in water. EN 12467 Category A classification confirms dimensional stability under full immersion — less than 1% thickness swelling. This is why fiber cement board is specified for wet rooms, swimming pool surrounds, and exterior facades worldwide.
Fire performance
Both standard gypsum and fiber cement board can achieve Class A2 reaction-to-fire classification. High-density Type F gypsum board achieves A1. In this category, gypsum board is a strong competitor — it performs well in fire-rated partition systems.
However, Terasun TSM's tested wall assembly achieves E 120 / EI 90 / EW 120 — 120-minute fire integrity and insulation. Comparable gypsum board systems typically achieve EI 60–90. For maximum fire resistance in fire compartmentalisation, the Terasun TSM tested system offers a performance advantage.
When gypsum board is appropriate
- • Dry internal partitions and ceilings
- • Corridor and corridor fire-rated walls (EI 60)
- • Where ease of cutting is critical
- • Budget-driven interior fit-out
- • Skimmed plaster finish requirements
When fiber cement board is correct
- • Exterior facades (all climates)
- • Wet rooms, showers, bathrooms
- • Swimming pool changing rooms
- • Fire-rated systems requiring E120/EI90/EW120
- • Render carrier on exterior walls
- • Steel frame sheathing (interior + exterior)
- • High-humidity industrial environments
FAQ
Can gypsum board be used in wet rooms?+
Standard gypsum board cannot. MR-grade gypsum with a properly installed waterproofing membrane can be used behind tiles in splash zones, but should not be used in areas of permanent immersion. Fiber cement board does not require an additional waterproofing layer — it is inherently suitable for wet areas.
Can gypsum board be used on exterior facades?+
No. Even MR gypsum board is not suitable for exterior facades exposed to weather. Gypsum is water-soluble and will structurally fail if directly exposed to rain. EN 12467 Category A fiber cement board is the correct choice for exterior use.
Which is easier to work with?+
Gypsum board is easier to cut (score-and-snap) and lighter to handle per panel. Fiber cement board requires a circular saw with a fibre cement blade and generates fine cement dust (wear P2 mask). However, fiber cement board requires no additional waterproofing membrane in wet rooms, saving time overall.