Trade-Specific Technical Knowledge and Theory
Trade-Specific Technical Knowledge and Theory
The theory paper asks why your trade works, not only how to repeat a gesture. Whatever your speciality - masonry, joinery, motor mechanics, electrical installation, refrigeration, tailoring, hairdressing or catering - the examiner wants correct trade vocabulary, material choices you can justify, and procedures described in the right order with quantities and units.
What is tested
- Vocabulary and definitions of tools, materials, components and common defects, written in the language of the paper.
- Material properties: hardness, conductivity, elasticity, water absorption, grain direction, heat resistance, shrinkage.
- Sequences: operations whose order cannot be reversed without damage (curing before loading, cooling before measuring, priming before painting).
- Quality criteria: dimensions, tolerances, finish, drying and curing times, standard ratios and dosages.
Core rules
- Name things with the exact technical term, not workshop slang, and give the unit after every number.
- Justify a material by its properties: "aluminium because it resists outdoor corrosion", not "because we always use it".
- Say which check proves the work is correct, and with which instrument.
- When a result depends on a prior condition, state the condition - a floor is tiled on a cured, dust-free screed, not on a fresh one.
Worked example
A concrete slab measures 3.5 m by 4 m and is 8 cm thick. The dosage is 350 kg of cement per m³, cement is sold in 50 kg bags, and 5 % is added for waste. How many bags are needed?
Volume = 3.5 × 4 × 0.08 = 1.12 m³ (8 cm converted to 0.08 m). Cement = 1.12 × 350 = 392 kg. With waste: 392 × 1.05 = 411.6 kg. Bags = 411.6 ÷ 50 = 8.23, so buy 9 bags. The reasoning matters as much as the figure: you round up because a bag cannot be bought in fractions and a lean mix weakens the slab.
Traps that cost marks
- Mixing millimetres, centimetres and metres inside one calculation.
- Confusing nominal (sawn) and finished (planed) timber sizes, so the finished piece comes out undersize.
- Forgetting waste, overlap, jointing or shrinkage allowances.
- Writing a bare number with no unit and no statement of rounding.
- Answering "the usual way" instead of describing the expected sequence step by step.