Work out how many blocks a wall needs and how much mortar goes with them. Enter the wall dimensions, deduct any openings, set your block size and joint thickness, and the calculator returns block count, mortar volume and bag quantities.
About 10, using the standard 440 × 215mm block with 10mm mortar joints. Multiply your net wall area in square metres by 10 and add wastage.
Roughly 0.012–0.02m³ per square metre of single-skin wall. A 1:5 or 1:6 cement to soft sand mix suits general blockwork; 1:4 is used below DPC and in more exposed conditions.
Dense aggregate blocks carry more load and give better sound resistance. Lightweight aerated blocks insulate better and are far easier to lift and cut. The inner leaf of a cavity wall is usually lightweight; loadbearing and below-ground work is usually dense.
These tools give you a reliable starting figure. When you’re ready to turn it into a costed, fixed-scope proposal, our team works across London, Dubai and Cairo on architecture, interior design and turnkey delivery.
