Bricklaying
What this domain tests
The SOLAS Bricklaying craft domain examines the theory behind the National Craft Certificate: mortar specification, bonding and setting out, block and brickwork to line and gauge, damp-proofing, cavity construction and the detailing that keeps a wall stable and weathertight. Expect to explain why a detail is built that way, not just name it. Questions are practical - mix proportions, bond identification and defect diagnosis - not just definitions.
Core rules
- Gauge: 65 mm brick plus 10 mm joint gives a 75 mm course; four courses rise 300 mm. A 215 mm block plus 10 mm joint gives 225 mm, so four block courses rise 900 mm. Work to a storey rod, not a tape.
- Bond: each course must lap the one below by at least a quarter brick, so no continuous vertical joint forms. Stretcher is half-bond; English alternates stretcher and header courses; Flemish alternates them within a course.
- Mortar: a common general-purpose mix is 1:1:6 cement:lime:sand by volume; use 1:3 or 1:4 cement:sand for engineering bricks and below DPC. Never retemper mortar that has started to stiffen.
- Cavity walls: keep the cavity clean; space wall ties at 900 mm horizontally and 450 mm vertically, closer around openings. Keep the DPC at least 150 mm above external ground and lap it with the DPM at thresholds.
Worked example
A 4.5 m × 2.7 m half-brick wall: 12.15 m². At 60 bricks/m², 12.15 × 60 = 729 bricks. Add 5% for cutting and waste: 729 × 1.05 = 765.4, so order 766. Mortar at roughly 0.03 m³/m² needs 12.15 × 0.03 = 0.36 m³, mixed in small batches.
Traps
Face-filled perpends with hollow centres; continuous vertical joints; setting out without checking diagonals; DPC less than 150 mm above external ground; and laying frog-down when the specification requires frog-up.