CTVET Ghana Certificate II - Blocklaying & Concreting common mistakes
CTVET Ghana Certificate II - Blocklaying & Concreting · Understand the traps and how to avoid them.
When asked to state the safe working load (SWL) or maximum safe lift of a scaffold or lifting gear, the candidate writes the breaking strength of the rope, chain or sling instead of the safe working load, or ignores the safety factor entirely.
Candidates memorise one number for a rope or chain and confuse the load at which it snaps with the load it may legally carry. The safety-factor idea (for example a factor of 5 to 6 for wire rope slings, higher for manila rope) is often learned as a formula to recite rather than as the reason a smaller number is the answer.
What to do instead
Practise a fixed three-step routine on every SWL question: identify the material, recall its safety factor, then divide the breaking strength by that factor and state the unit. Write the division out in the answer so the examiner sees the reasoning. Learn typical factors as a short table (wire rope slings about 5, chain slings about 4, fibre rope about 6 to 10 depending on use) and do five worked examples before the exam.
The candidate names the correct tool in words but describes its use wrongly, for example saying a spirit level is used to check squareness of a corner, a plumb bob is used to check a surface is horizontal, or a float is used to compact concrete.
Tool questions are usually revised as a list of names with one-line definitions. Under exam pressure the definitions blur because the candidate has never actually handled the tool or watched it being used, so levelling, plumbing, squaring and compacting get mixed up.
What to do instead
Build a two-column revision sheet: tool on the left, the single physical quantity it checks or action it performs on the right (level = horizontal, plumb = vertical, square = 90 degrees, float = smooth surface, vibrator = compact). For each tool, add one sentence describing the posture of the user and the reading taken. Where possible handle the tool on site or in the workshop and say the definition aloud while doing it.
When describing setting out a rectangular building, the candidate lists steps in the wrong order: pegs driven before the baseline is established, the diagonal check performed before the right angle is set, or the profile boards set before the corners are transferred.
Setting-out is a sequence, but candidates learn the individual operations (peg out, square off, check diagonals, set profiles) as isolated facts and never rehearse them as an ordered procedure. They also fail to see that each step depends on the previous one being correct.
What to do instead
Memorise the sequence as a numbered chain of six to eight steps and practise writing it from memory: clear and level the site, establish a baseline from a fixed reference, set the first corner square using the 3-4-5 method, measure and peg the remaining corners, check both diagonals are equal and adjust, transfer lines to profile boards clear of the excavation, then mark the trench or foundation line. Learn the 3-4-5 (or 6-8-10) triangle as the squaring method and state that diagonals must be equal before profiles are set.
The candidate describes blockwork in the wrong construction order or with the wrong bonding detail: stretching a line after the first course is laid, failing to state that the first course is set out from the corners and checked for level and square, or describing a stretcher bond with continuous vertical joints.
Bonding rules are learned as pictures rather than as rules. The candidate can recognise a bond in a diagram but cannot state the governing principle, namely that vertical joints in successive courses must be offset by half or quarter of a block and never form a continuous line.
What to do instead
Learn one governing rule and apply it to every bond question: vertical joints must be broken. Then learn the specific offsets (half-block for stretcher bond, quarter-block for English bond, and the requirement that a quoin or corner block be laid true and plumb). Practise writing the first-course procedure: set out corners, lay corner blocks, stretch the line, fill between, check level and plumb with spirit level and plumb rule, then rake out joints for the next course.
When asked for a concrete mix ratio, the candidate gives a ratio without stating what the numbers refer to, or reverses the order, for example writing 1:3:6 as cement:sand:coarse aggregate when the intended mix is a richer one, or stating a water-cement ratio above 0.6 for a structural mix without comment.
The three-number notation is memorised as a string without the underlying meaning. Candidates also confuse nominal mixes (by volume) with design mixes (by weight) and do not connect the water-cement ratio to strength and durability.
What to do instead
Always write the ratio with labels attached: cement : fine aggregate : coarse aggregate, by volume, for a nominal mix. Learn three or four standard nominal mixes with their typical uses (for example 1:3:6 for mass concrete and blinding, 1:2:4 for general reinforced work, 1:1.5:3 for higher-strength structural work), and state that a lower water-cement ratio gives higher strength and better durability, with typical structural values around 0.45 to 0.55. Practise converting a nominal mix to a batch quantity.
The candidate describes curing as something done only if time allows, or states a curing period of a day or two for structural concrete, or says curing means drying the concrete out.
Curing is often taught as a footnote after placing and finishing. Candidates do not connect it to the hydration reaction, so they see it as housekeeping rather than as the process that develops strength, and they confuse 'keeping it wet' with 'letting it dry'.
What to do instead
Learn the causal chain: cement hardens by hydration, hydration needs water, so concrete must be kept moist to gain strength and resist cracking. State typical minimum curing periods (commonly about 7 days for ordinary Portland cement concrete, longer in hot or aggressive conditions) and name the methods (ponding, wet covering, polythene sheeting, curing compounds). In answers, always give the period and the method together.
When asked for bar spacing, cover or lap length, the candidate gives a single figure with no reference to the bar diameter, the exposure condition or the structural element, and cannot explain what cover is protecting the steel from.
Reinforcement details are learned as isolated numbers copied from a table. Candidates do not realise that cover and lap lengths are expressed as multiples of bar diameter and depend on exposure, so they cannot adapt the answer to the case in the question.
What to do instead
Learn the principle first: cover is the concrete between the steel and the surface, protecting the bar from corrosion and providing fire resistance and bond. Then learn that cover and lap lengths are stated as multiples of bar diameter (for example a lap of many diameters, with cover varying by exposure class). Practise reading a simple bar-bending schedule and stating cover as 'so many times the bar diameter' rather than as a bare number.
The candidate describes formwork removal without reference to the element and its span, for example saying all formwork is struck after 24 hours, or describes striking as simply pulling the boards off without mentioning props, wedges or the sequence.
Striking times are remembered as a single figure. Candidates do not distinguish between side forms, which can be removed early to allow curing of the faces, and soffit formwork and props, which carry the weight of the slab or beam and must stay until the concrete has gained sufficient strength.
What to do instead
Learn the two-category rule: vertical side forms may be struck once the concrete is strong enough not to be damaged (often around 24 hours), while soffit forms and props under slabs and beams remain until the concrete reaches adequate strength, typically guided by the span and often 7 to 14 days or more. Learn the striking sequence (ease wedges, lower props gradually, remove from the centre outwards) and the reason for it, namely avoiding shock loading on young concrete.
In technical drawing and quantity questions, the candidate cannot read a simple plan or section, confuses the scale on a drawing with the real dimension, or computes a quantity without allowing for wastage and without stating the unit.
Drawing and measurement are often skipped in favour of 'practical' topics. Candidates do not practise converting a scaled length to a real length, do not know the standard scales, and treat quantity take-off as arithmetic rather than as a measured, ordered process with units and allowances.
What to do instead
Practise a fixed routine: read the title block and scale, identify the views, measure the scaled length, multiply by the scale factor, and state the real dimension with units. For quantities, use a take-off sheet with description, number, length, width, depth and unit, and add a stated wastage allowance (commonly around 5 to 10 percent for blocks and mortar). Do three worked examples each for a wall area, a block count and a concrete volume before the exam.
The candidate treats the practical project as a separate exercise from the theory paper and cannot explain or justify what was done on site, or in the entrepreneurship section gives a business plan with no costing, no break-even figure and no awareness of the Ghanaian regulatory and tax context.
Practical work is often done by rote under instruction without the candidate articulating why each step is taken, so the trade-assessment oral and the theory paper expose gaps. Similarly, entrepreneurship is revised as definitions of terms rather than as a costing exercise, so candidates cannot produce a simple estimate, price or cash-flow statement.
What to do instead
For each practical task, keep a short log recording what was done, the tools used, the checks made and the reason for each step; rehearse explaining it aloud in two minutes. For entrepreneurship, practise a one-page cost build-up for a small job (materials, labour, transport, overhead, profit margin) and compute a break-even point and a simple cash-flow. Learn that a small contractor must register the business, keep records and account for tax, and be able to name the relevant Ghanaian authorities at a general level.