Product comparison
Fiber Cement Board vs Plywood
For exterior facades and exterior walls — fire class, moisture performance, and CE certification compared. Which is correct for your project?
Fire class
A1 vs Class D
Buildings 18 m+
FCB yes · Plywood no
Moisture
Category A vs delamination risk
Comparison table
| Property | Plywood (EN 636-3) | Fiber Cement Board (Terasun TSM) |
|---|---|---|
| Fire class | Class D–E (combustible) | ✓Class A1 (non-combustible) |
| Exterior facade suitability | Conditional (protected only) | ✓Yes — all climates |
| Moisture resistance | Delamination risk at cut edges | ✓EN 12467 Category A — immersion stable |
| Mould risk | Yes (organic material) | ✓None (inorganic) |
| Weight (12 mm) | 7–8 kg/m² | 9.96 kg/m² |
| CE standard | EN 636 | EN 12467 — CE 1023-CPR-1565 P |
| ETA | — | ✓ETA 24/0895 |
| Fire assembly rating | Not tested for E/EI/EW | ✓E120 / EI90 / EW120 |
| Buildings above 18 m (A2 req.) | Does not comply | ✓Yes — A1 |
| EPD / LEED-BREEAM | Limited | ✓EPD-IES-0018268 |
| Material cost | Lower | Higher |
Fire regulations for facades
In most EU member states, building regulations derived from Eurocode and the EU Construction Products Regulation require facade materials to be Class A1 or A2 on buildings above 18 m height. Standard and even fire-retardant-treated plywood typically achieves at best Class B-C, not A2.
Terasun TSM fiber cement board achieves A1 — non-combustible, compliant for facades on all building heights. The tested wall assembly achieves E 120 / EI 90 / EW 120 for compartmentalisation, a performance level not achievable with plywood-based systems.
Moisture and durability
Exterior-grade plywood (EN 636-3) uses phenolic resin adhesive to resist moisture, but cut edges are still vulnerable to delamination when repeatedly wetted. In ventilated facade systems in Nordic, Atlantic, and Alpine climates, moisture ingress through facade gaps and wind-driven rain will eventually compromise plywood integrity — typically within 10–20 years.
Fiber cement board with EN 12467 Category A classification has less than 1% thickness swelling under full immersion. It has no organic content, so it does not support mould or biological degradation. Service life in exterior applications exceeds 40 years with normal maintenance.
When plywood is appropriate
- • Structural roof decking (under membranes)
- • Internal sheathing in dry conditions
- • Low-rise buildings where Class D is acceptable
- • Curved surface applications
- • Cost-driven projects with no fire or moisture constraints
When fiber cement board is correct
- • All ventilated facade systems
- • Buildings above 18 m (A2 required)
- • Wet climates (Scandinavia, UK, Atlantic, Alpine)
- • Fire-rated assemblies E120/EI90/EW120
- • Render carrier (exterior plaster substrate)
- • Steel frame exterior sheathing
- • LEED, BREEAM, DGNB projects
FAQ
Can plywood be used on ventilated facades?+
EN 636-3 plywood can be used on low-rise ventilated facades where fire class D is acceptable and moisture exposure is managed. On buildings above 18 m or in wet northern climates, fiber cement board is the technically correct and regulation-compliant choice.
Is fiber cement board heavier than plywood?+
Terasun TSM at 12 mm weighs 9.96 kg/m², slightly more than 12 mm structural plywood at 7–8 kg/m². Facade applications typically use 8–10 mm fiber cement board, which is comparable or lighter than structural plywood.
Can fire-retardant treated plywood replace fiber cement board on facades?+
No. FR-treated plywood typically achieves Class B-C at best, and cannot match the A1 classification of fiber cement board. It also remains susceptible to moisture delamination in repeated wetting conditions. For non-combustible, moisture-stable facade systems, fiber cement board is the correct specification.