6.10.12 Fixing floor decking and ceilings
Floor decking and ceilings shall be adequately fixed using a material of adequate strength and moisture resistance.
Joist spacing and decking thickness should be compatible. Material standards and minimum board thicknesses for domestic loads (imposed load of 1.5kN/m2) are shown in Table 6.
Table 6: Joist spacing and decking type
| Material | Standard | Minimum thickness of decking (mm): 400mm joist centres | Minimum thickness of decking (mm): 600mm joist centres |
|---|---|---|---|
| Chipboard | BS EN 312 moisture-resistant type P5 | 18 | 22 |
| Plywood | BS EN 636 | 15 | 18 |
| Oriented strand board type OSB3 | BS EN 300 | 15 | 18 |
| Other materials | In accordance with Technical Requirement R3 |
In England and Wales, the thicknesses listed above may not achieve the 15kg/m2 mass required to meet sound insulation requirements.
Flooring should be fixed at maximum 300mm centres using self-tapping screws or fixings approved by the LSF manufacturer and in accordance with Chapter 6.4 ‘Timber and concrete upper floors’.
Plasterboard should be fixed in accordance with Chapter 9.2 ‘Wall and ceiling finishes’, using self-drilling, self-tapping screws.
Last updated: 2nd January 2024