How Many Studs Do I Need for a Stud Wall?

How We Calculated This

Stud walls have vertical timber studs at regular centres between a top plate (head) and bottom plate (sole):

• Wall length: 3m
• Stud centres: 400mm
• Studs: (3000 ÷ 400) + 1 = 8.5, round up to 9 studs
• Head plate: 1 × 3m length
• Sole plate: 1 × 3m length
• Noggings (horizontal bracing): 1 row at mid-height = 8 noggings

400mm vs 600mm Centres

• 400mm centres: Standard for plasterboard (1200mm wide boards divide evenly by 400). More rigid, better sound insulation. Recommended for most domestic work.
• 600mm centres: Acceptable where only one layer of plasterboard is used and no heavy fixings are needed. Uses less timber.

Timber Sizes

• 75 × 50mm CLS: Non-loadbearing partitions (most common)
• 100 × 50mm CLS: Thicker walls for better sound insulation or services
• 75 × 38mm: Budget option for non-loadbearing walls
• CLS (Canadian Lumber Standard): Rounded edges, consistent dimensions, easy to plasterboard

Quick Reference

• 2m wall at 400mm: 6 studs
• 3m wall at 400mm: 9 studs
• 4m wall at 400mm: 11 studs
• 3m wall at 600mm: 6 studs
• 4m wall at 600mm: 8 studs

Tips

Fix the sole plate to the floor first, then the head plate to the ceiling joists. Mark stud positions on both plates before cutting any timber. Use a plumb line or laser to ensure studs are vertical. Add extra studs around door openings, and use a double lintel above door frames. Fix noggings at mid-height for rigidity and to support plasterboard edges.