A decking board is a wide, thick plank used as the walking surface on a deck (timber terrace). Decking boards are screwed onto joists and form the visible surface you walk on, sit on and place your garden furniture on.
Materials
| Material | Lifespan | Price | Maintenance |
|---|---|---|---|
| Bangkirai (hardwood) | 25-30 years | High | Optional oiling |
| Ipe (hardwood) | 30+ years | Very high | Optional oiling |
| Douglas fir | 10-15 years | Medium | Oil or allow to weather grey |
| Thermowood | 15-20 years | Medium-high | Optional oiling |
| Pressure-treated softwood | 8-12 years | Low | None |
| Composite (WPC) | 20-25 years | High | None (just cleaning) |
Dimensions
| Size (mm) | Application |
|---|---|
| 21 x 145 | Standard decking board |
| 25 x 145 | Sturdier, less deflection |
| 28 x 145 | Premium, allows greater joist spacing |
| 21 x 195 | Wide board, fewer gaps |
Profiling
Decking boards often have profiling on one or both sides:
- Smooth — Clean appearance, easy to keep clean
- Ribbed (grooved) — Less slippery in wet weather, but dirt accumulates in the grooves
- Fine ribbed — Compromise between grip and ease of maintenance
> Nowadays many people opt for the smooth side — research shows that ribbed boards are not necessarily less slippery in wet weather, while the grooves are harder to keep clean.
Installation
1. Lay decking boards on the joists
2. Gap between boards: 5-8 mm (expansion — timber expands with moisture)
3. Pre-drill with hardwood (prevents splitting)
4. Use stainless steel screws (2 screws per crossing with a joist)
5. Ends must always rest on a joist
Related terms
- Joist
- Deck
- Hardwood
- Thermowood
- Expansion gap