Brick Wall Calculator

How brick quantities are worked out

A single-skin brick wall uses about 60 standard UK bricks (215 × 102.5 × 65mm with 10mm joints) per square metre. Multiply wall area by 60 for the brick count, and allow about 0.5kg of mortar per brick. Double-skin walls double both figures.

Worked example: a 5 m × 2 m garden wall

The face is 10 m². A half-brick (102.5 mm) UK wall takes about 60 bricks per square metre, so that is 600 bricks. Add 5% for cutting and breakage — 30 more — giving 630 bricks to order. If you are building two skins, or a one-brick-thick (215 mm) wall, that figure doubles to roughly 1,200 bricks per 100 m² of face.

Mortar, and how much of it

Bricklaying guides estimate roughly 1 m³ of mixed mortar per 1,000 bricks — about 1.2 tonnes of building sand plus 250 kg of cement at a 1:5 mix with plasticiser. For a 600-brick job that is around 0.6 m³, so a tonne bulk bag of sand and five or six bags of cement covers it with some to spare for pointing.

Lintels, ties and damp

Any opening wider than about 600 mm needs a lintel with at least 150 mm bearing either side. Cavity walls need wall ties at 450 mm horizontal and 300 mm vertical centres, sloping slightly outwards so water runs back into the cavity and down the weep holes. Fit a damp-proof course 150 mm above ground level on every wall that touches the soil.

Buying bricks without grief

Buy all the bricks in one go from one batch — different batches vary in shade and the difference is obvious once the wall is up. Soft handmade and reclaimed bricks are for cosmetic work in sheltered spots; engineering bricks are dense, waterproof and miserable to cut, so use them where damp resistance matters and not just because they are strong.

Common mistakes

Estimating without waste and then driving across town for ten more bricks. Laying in frost, which ruins the mortar bond. Using the wrong mortar strength — a hard mortar around a soft brick cracks the brick rather than the joint. And forgetting that a long, thin wall needs piers every 3–4 m to stay upright.