Elective Units of Competency: Specialist Roof Tiling Skills
What the elective units cover
Electives let a candidate specialise: concrete and terracotta tile fixing, slate and shingle work, metal roofing and wall cladding, steep-pitch and heritage work, waterproofing and flashings, and supervision or business-related competencies. Questions in this domain reward precision about materials, compatibility and detailing rather than general safety knowledge.
Concepts you must know
- Tile types and performance: concrete versus terracotta versus slate; porosity, frost resistance, weight per square metre, and the effect of weight on battens and structure.
- Fixing methods: nail, screw, clip and mortar bedding; which courses and perimeter tiles require mechanical fixing; exposure to wind and edge zones.
- Flashing detail: valley, ridge, hip, apron, step and counter flashings; the principle that water must be directed over, not behind, the next material, and that laps run downhill.
- Sarking and condensation: permeable versus impermeable sarking and when each suits a roof.
- Steep pitch and heritage work: additional fixing, safety access, and matching existing profiles and colours.
- Metal roofing and cladding: minimum pitch, end laps, fastener placement, thermal movement.
Traps in questions
Distractors swap lap direction, mix compatible and incompatible materials (for example, dissimilar metals causing corrosion), or apply a low-pitch rule to a steep roof. Another common trap is assuming every tile is nailed; fixing requirements vary with wind zone, pitch and position.
Rule of thumb
Water flows downhill and laps follow it - any option that puts an upper material behind a lower one is wrong. For material choice, check weight, pitch and exposure before aesthetics.
Worked example
A question describes a valley where the flashing underlap is reversed. The correct response is that the higher roof's flashing must overlap the lower roof's, directing water into the valley gutter, so the reversed detail will leak and must be reworked.