How Many Blocks Per m²?

How We Calculated This

• Block + joint width: 440 + 10 = 450mm
• Block + joint height: 215 + 10 = 225mm
• Blocks per metre (horizontal): 1,000 / 450 = 2.22
• Courses per metre (vertical): 1,000 / 225 = 4.44
• Blocks per m²: 2.22 × 4.44 = 9.88, say 10

Quick Reference Table

• 5m² wall: 50 blocks
• 10m² wall: 100 blocks
• 12m² wall (5m × 2.4m): 120 blocks
• 20m² wall: 200 blocks

Add 5–10% for waste, cutting, and breakage.

Common Block Sizes

• 440 × 215 × 100mm: Standard — 10 per m²
• 440 × 215 × 140mm: Wide leaf — still 10 per m² (same face size)
• 440 × 215 × 200mm: Thick foundation blocks — 10 per m²
• 390 × 190mm (smaller): ~13 per m²

Block Types

• Dense concrete (7.3N/mm²): Foundations, below-DPC, retaining walls
• Lightweight aggregate (3.6N/mm²): Inner leaf of cavity walls, internal walls
• Aircrete/aerated (2.9–7.3N/mm²): Thermal performance, easy to cut
• Insulating blocks: Low U-value for energy-efficient builds

Mortar Needed

For 10 blocks per m², you need approximately 0.01m³ of mortar per m² of blockwork. A standard 25kg bag of cement mixed 1:4 with sand yields about 0.01m³ — roughly 1 bag per m².