Brick & BlockCount Calculator

For standard UK bricks (215mm × 102.5mm × 65mm) in stretcher bond with a 10mm mortar joint, the brick count is 60 bricks per m². English bond uses 80 bricks/m² because alternate courses are laid as headers, effectively using two bricks where stretcher bond uses one. Flemish bond (alternating headers and stretchers in each course) uses approximately 75 bricks/m². At 12mm joints the counts drop slightly: stretcher 56/m², English 75/m², Flemish 70/m².

A common rule of thumb is one 25kg bag of ready-mixed mortar per 50 standard bricks in stretcher bond. For a site-mixed 1:1:6 mortar (cement:lime:sand by volume), you need approximately 0.5 bags of cement and 3 bags of sand per m² of single-skin brickwork. For cavity wall construction, calculate mortar for each leaf separately. Always add 10–15% waste to mortar calculations — wastage from pointing, spillage, and board drying is inevitable.

Common (or engineering) bricks are used below DPC, in foundations, and for internal walls — they are durable but not aesthetically finished. Facing bricks have a decorative surface on one face and are used for external visible walls. Stock bricks (a regional type) are semi-handmade and vary in texture. In 2026, common bricks cost £0.25–£0.45 each; basic facing bricks cost £0.50–£0.80 each; premium handmade bricks can exceed £2.00 each. The calculator uses a mid-range facing brick price of approximately £0.65.

Dense concrete blocks (solid, 7.3 N/mm²) have a U-value conductivity of around 1.13 W/mK — poor insulation. Medium-density hollow blocks are better (~0.57 W/mK). Lightweight aircrete blocks (Thermalite, Celcon, etc.) at 100mm thick achieve around 0.11 W/mK, making them very good insulators. Standard bricks are approximately 0.77 W/mK. In a modern Part L-compliant cavity wall, the insulation layer in the cavity dominates the thermal performance — the block and brick type matters less than the cavity fill.

A standard pallet holds 400–500 bricks. At £0.50–£0.80 per brick (mid-range facing brick), a pallet costs £200–£400 plus delivery. Delivery typically adds £50–£150 depending on distance and supplier — for large jobs, negotiate delivered pallet prices directly with a builders' merchant. Prices rose sharply in 2022–2024 due to energy costs in brick kilns; 2026 prices have stabilised but remain 20–30% above pre-2022 levels.

Cavity walls in England must comply with Part C (moisture resistance), Part L (thermal performance), and Part A (structural). The minimum cavity width is 50mm for insulated cavities under current Part L 2021; most new-build full-fill insulation is 100mm cavity. Wall ties must comply with BS EN 845-1 and be spaced at no more than 900mm horizontal, 450mm vertical in standard conditions. The U-value target for new-build walls is 0.18 W/m²K under Part L 2021.

Industry standard wastage for standard brickwork is 5% for straightforward rectangular walls and 10–15% for walls with many openings, complex bond patterns, or site-cut bricks. For block work, 5–10% is typical. The calculator defaults to 10% waste, which is appropriate for most domestic extensions and new builds. For heritage restoration work using handmade bricks, increase wastage to 15–20% to account for breakage and matching variations.