How Much Loft Boarding Do I Need?
Quick Answer
Area to board ÷ 1.44m² per board + 10% waste
A 15m² loft storage area needs ~12 boards (2400 × 600mm) plus loft legs and screws
How We Calculated This
- Area to board: 15m²
- Board size: 2400 × 600mm = 1.44m²
- Boards: 15 ÷ 1.44 = 10.4
- Plus 10% waste: ~12 boards
Loft Legs
Loft legs raise the boarding above the insulation so you don’t compress it (which reduces its effectiveness). Space them at 600mm centres along each joist:
- 175mm loft legs: For 100mm insulation between joists + 170mm cross-laid
- Standard leg spacing: 600mm along joists, one per board width
- Legs needed: Roughly 8–10 per m² of boarding
Board Types
- Chipboard (P5 moisture resistant): 18mm thick, most common. T&G edges
- Loft board kits: Pre-cut boards with loft legs included
- OSB board: Stronger alternative, 18mm
Important Considerations
- Do not compress loft insulation — always use raised legs
- Check joist spacing (typically 400mm or 600mm centres)
- Maximum storage load: typically 25 kg/m² for light storage
- Ensure adequate ventilation at the eaves is maintained
Last updated: April 2026