How Much Mortar for a Wall?

How We Calculated This

For single-skin (half-brick) brickwork with 10mm joints:

• Mortar volume per m²: approximately 0.03m³
• For 10m²: 10 × 0.03 = 0.3m³ mortar
• At 1:6 mix ratio, cement per m³ mortar: ~6.5 bags (25kg)
• 0.3m³ needs: 0.3 × 6.5 = ~2 bags cement and 0.3m³ sand

In practice, with waste allowance: ~7 bags cement for 10m² is a safe estimate for 1:4 mix.

Mortar Per m² by Wall Type

• Half-brick wall (single skin): 0.03m³/m²
• One-brick wall (215mm): 0.06m³/m²
• Block wall (100mm blocks): 0.01m³/m²
• Block wall (140mm blocks): 0.012m³/m²

Common Mortar Mix Ratios

• General purpose (M4/class ii): 1:1:6 (cement:lime:sand) or 1:5 with plasticiser
• Strong (M6/class i): 1:0.5:4.5 or 1:4 with plasticiser
• Below DPC/retaining: 1:3 (cement:sand) — no lime or plasticiser

Materials Checklist

• Cement: 25kg bags (OPC or masonry cement)
• Building sand (soft sand): Sold by bulk bag (~850kg) or loose
• Lime (optional): Improves workability and frost resistance
• Plasticiser: Alternative to lime for workability

Tips

• Always mix mortar to a consistent ratio — inconsistent mixes cause colour variation in joints
• Use the same sand throughout the job for consistent colour
• Only mix as much mortar as can be used within 1–2 hours
• Do not add water to re-temper mortar that has started to set