Elective Units of Competency: Specialist and Contextual Skills
What elective units add
Elective units let a candidate specialise. Typical electives in bricklaying qualifications include constructing masonry arches and features, laying refractory or fire-rated masonry, installing damp-proof courses and flashings, rendering, paving, and heritage or restoration work. Questions here reward precise sequencing and knowledge of why a detail is specified.
Concepts to master
Damp-proof course (DPC) and flashings. A DPC interrupts rising moisture; flashings shed water at junctions. The trap is placement: a DPC must be continuous and lapped correctly, and weep holes must remain clear so moisture can escape.
Arches and openings. An arch transfers load around an opening through compression. Know voussoirs, the skewback, the springing line and centring. The critical rule is that centring stays in place until the mortar has gained sufficient strength.
Refractory and fire-rated masonry. Fire-rated construction depends on continuity and correct mortar, not just brick type. Gaps at penetrations defeat the rating.
Rendering and paving. For rendering, surface preparation and curing control success; for paving, base preparation and fall for drainage matter most.
Heritage work. Match materials and mortar strength to the original fabric; hard modern mortar can damage soft historic bricks.
Traps in questions
- Removing centring too early from an arch.
- Specifying a strong mortar for heritage brick.
- Forgetting that flashings and weep holes work together as a system.
- Treating fire rating as a property of the brick alone.
Rule of thumb
For any elective detail, ask: What is this element protecting, and what happens if it is interrupted? Continuity is almost always the answer.
Worked example
A brick arch over a 1.2 m opening is built on timber centring. The mortar is a 1:1:6 mix. Centring must remain until the mortar has set sufficiently to carry the arch load; striking it early allows the arch to drop and crack. The check is: has the mortar achieved adequate strength, and is the arch bearing correctly on both skewbacks?