Practical Workshop Skills and Project Work
Domain 9 covers Practical Workshop Skills and Project Work: the hand skills assessed in the workshop - masonry, plastering, concreting and simple carpentry - plus the record, drawing and estimate that make up the project file.
Masonry
- Soak bricks before laying, lay frog up, spread mortar about 10 mm, keep the line tight and check plumb and level every course.
- English bond alternates header and stretcher courses; Flemish bond alternates header and stretcher within the same course. Rake joints 10–12 mm deep to give plaster a key.
Plastering
- Wet the wall, apply 12 mm internally (15–20 mm externally in two coats), rule off with a straight edge, finish with a wooden then a steel float, and cure for at least 7 days.
Concreting
- Batch by volume with a measuring box, mix to uniform colour, place in 150–300 mm layers, compact with a needle vibrator, and cure 7–14 days.
- Workability is checked by slump: a standard cone 300 mm high; slump is the drop of the top of the concrete. Cubes of 150 mm are tested at 7 and 28 days.
Project work
A good file has a site plan, working drawing, measurement sheet, abstract of cost, method statement and photographs; the viva asks why each choice was made.
Worked example
A slump cone 300 mm high settles to 275 mm. Reasoning: slump = 300 − 275 = 25 mm, a stiff mix suitable for mass concrete; for a heavily reinforced slab a slump of 75–100 mm with a plasticiser would place and compact better.
Traps
- Adding water to a stiff mix instead of remixing to the correct water-cement ratio.
- Over-vibrating, which causes segregation.
- Plastering a dry wall or skipping curing, causing shrinkage cracks.