NVQ Diploma in Bricklaying (Construction) Bricklaying Materials, Tools and Resources Syllabus

Bricklaying Materials, Tools and Resources syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Bricklaying Materials, Tools and Resources in NVQ Diploma in Bricklaying (Construction), not a summary of it.

1. 1

   Bricks, Blocks and Masonry Units

   4 topics

   • Clay, calcium silicate and concrete bricks
     • Facing, common and engineering bricks
     • Frost resistance (F) and soluble salt (S) designations
   • Aggregate and aerated concrete blocks
     • Dense, lightweight and thermal block grades
   • Brick formats and standard dimensions
     • Coordinating and work sizes; the 225mm format
   • Storage, handling and protection of units on site
2. 2

   Mortars, Admixtures and Mixing

   5 topics

   • Mortar constituents: cement, lime, sand and water
     • Designation mortars and BS EN 998-2 classes
   • Mortar mix proportions for differing exposure
     • Gauging and consistency control
   • Admixtures: plasticisers, retarders and accelerators
   • Mixing methods, water-cement ratio and retempering
   • Hot and cold weather working practices
3. 3

   Hand Tools and Powered Equipment

   4 topics

   • Trowels, jointers, lines and spirit levels
   • Setting-out tools: gauge rods, profiles and boat levels
   • Cutting equipment: bolster, lump hammer and disc cutters
     • Dust suppression and abrasive wheel regulations
   • Inspection, maintenance and storage of tools
4. 4

   Ancillary Components and Fixings

   5 topics

   • Wall ties, types and embedment requirements
     • Ties for cavity walls and movement joints
   • Damp-proof courses and damp-proof membranes
   • Cavity trays, weep vents and stop ends
   • Lintels, padstones, reinforcement and bed-joint mesh
   • Insulation: full-fill and partial-fill cavity products

Bricklaying Materials, Tools and Resources flashcards for NVQ Diploma in Bricklaying (Construction)

21 of 53 cards from the Bricklaying Materials, Tools and Resources deck — real questions with worked answers.

1. How are clay bricks manufactured and what gives them their colour and durability?

   Clay bricks are formed from clay (by extrusion/wire-cutting, soft-mud moulding or pressing) then fired in a kiln at roughly $900$–$1200\,^{\circ}\text{C}$. Firing vitrifies the clay; colour comes from clay mineralogy and firing temperature, and higher firing gives greater density, strength and durability.

2. What are calcium silicate (sand-lime) bricks made from and how are they cured?

   They are made from sand (or crushed flint) blended with hydrated lime and water, pressed to shape, then cured under high-pressure steam in an autoclave. They have a uniform colour and sharp arrises, but are more prone to moisture/drying shrinkage movement than clay.

3. How do concrete bricks differ from clay bricks in manufacture and behaviour?

   Concrete bricks are made from cement, fine and coarse aggregate and water, moulded and air/steam cured (not fired). They have very consistent dimensions but exhibit initial drying shrinkage, so movement joints and care over moisture are required.

4. What are the two main types of lightweight block and how do they differ?

   Aggregate (dense/lightweight) blocks are made from cement plus aggregate such as crushed stone, clinker or expanded clay. Aerated (autoclaved aerated concrete, AAC) blocks use cement, lime, sand and an aerating agent (aluminium powder) that creates air bubbles, giving a very light block with excellent thermal insulation but lower compressive strength.

5. Why are aerated concrete (AAC) blocks valued in cavity walls?

   Their entrained air voids give very low density and a low thermal conductivity (typically around $0.10$–$0.15\,\text{W/m}\cdot\text{K}$), so they greatly improve the wall's thermal insulation. They are also light to handle and easy to cut, though they need care to avoid surface damage.

6. What is the standard UK metric brick format (work size)?

   The standard UK metric brick work size is $215\,\text{mm} \times 102.5\,\text{mm} \times 65\,\text{mm}$ (length × width × height).

7. What is the difference between the 'work size' and 'coordinating size' of a brick?

   The work size is the actual manufactured brick dimension ($215 \times 102.5 \times 65\,\text{mm}$). The coordinating size includes one $10\,\text{mm}$ mortar joint, giving $225 \times 112.5 \times 75\,\text{mm}$, which is the modular space a brick plus joint occupies.

8. Why are the standard brick dimensions based on a 3:2:1 relationship?

   Including a $10\,\text{mm}$ joint each way, a brick coordinates as $225 \times 112.5 \times 75\,\text{mm}$, so length : width : height is $225 : 112.5 : 75 = 3 : 1.5 : 1$. This lets bricks bond together neatly in any direction so headers and stretchers align across courses.

9. How many courses of standard brickwork rise per metre of height, and what is the standard gauge?

   With a $65\,\text{mm}$ brick and $10\,\text{mm}$ bed joint the gauge is $75\,\text{mm}$ per course, so four courses rise $300\,\text{mm}$. Therefore $1000 \div 75 \approx 13.33$ courses per metre (commonly gauged as four courses to $300\,\text{mm}$).

10. What is a 'frog' and how should a frogged brick normally be laid?

    A frog is the indentation pressed into one or both bed faces of a brick. A single-frog brick should be laid frog upwards so the frog is filled with mortar, giving a fully solid bed, better bond and improved load transfer and sound insulation.

11. State the recommended way to store bricks and blocks delivered to site.

    Stack units on a clean, level, well-drained base (on bearers/pallets clear of the ground), in stacks of limited height to avoid toppling, and cover with waterproof sheeting to keep them dry while allowing some ventilation. Keep different types separated and remove banding carefully.

12. Why must facing bricks and lime-based units be protected from saturation before use?

    Saturated units bleed water into the mortar (affecting set), increase the risk of efflorescence and frost damage if laid wet then frozen, and lime/soluble salts can leach to the face causing staining. Keeping them dry and covered preserves appearance and durability.

13. What are the four basic constituents of bricklaying mortar and the role of each?

    Cement (the binder providing strength and set), lime (improves workability, water retention and bond, and allows slight movement/autogenous healing), sand (the fine aggregate giving bulk and controlling shrinkage), and water (hydrates the cement and makes the mix workable).

14. What does lime contribute to a mortar that a plain cement:sand mix lacks?

    Lime improves workability and water retention (so the mortar does not stiffen too fast against absorbent bricks), increases bond and reduces cracking by allowing minor movement, and can self-heal fine cracks. This is why a cement:lime:sand mortar is often preferred over cement:sand for facework.

15. Give a typical general-purpose mortar mix proportion by volume for normal exposure.

    A common general-purpose mix is cement : lime : sand of $1 : 1 : 6$ (or $1 : 6$ cement:sand with a plasticiser). This suits most above-DPC brickwork in normal exposure conditions.

16. What mortar mix is suitable for severe exposure or work below DPC, and why is it stronger?

    A richer mix of cement : lime : sand around $1 : \tfrac{1}{4} : 3$ (or $1 : 3$ cement:sand) is used for severe exposure, retaining walls, parapets and below DPC. The higher cement content gives greater strength and frost/durability resistance where the masonry is wet and exposed.

17. Why should you never use a mortar much stronger than the bricks it bonds?

    A mortar stronger and harder than the masonry units cannot accommodate movement, so thermal/moisture movement cracks the bricks rather than the joints. A slightly weaker, more flexible mortar concentrates any movement and cracking in the joints, which are easily repointed.

18. What is a plasticiser (air-entraining admixture) and what does it do to mortar?

    A plasticiser entrains many tiny air bubbles into the mortar, improving workability and water retention without adding extra water, and the air voids improve frost resistance of the hardened mortar. It is often used as an alternative to lime in cement:sand mortars.

19. What is the function of a retarder admixture in mortar or render?

    A retarder slows the hydration/setting of the cement, extending the workable (open) time. It is useful in hot weather or for ready-to-use 'retarded' mortars delivered to site, keeping the mortar usable for an extended period before it sets.

20. What does an accelerator admixture do, and what must be avoided in masonry mortars?

    An accelerator speeds up setting and early strength gain, useful in cold weather. Crucially, chloride-based accelerators (e.g. calcium chloride) must NOT be used where there is embedded metal — wall ties, reinforcement, lintels — because chlorides cause corrosion; only chloride-free accelerators are permitted.

21. Define the water-cement ratio and explain its effect on mortar/concrete strength.

    The water-cement ratio is the mass of water divided by the mass of cement: $\dfrac{w}{c} = \dfrac{\text{mass of water}}{\text{mass of cement}}$. A lower ratio generally gives higher strength and durability; too much water increases workability but reduces strength and increases shrinkage and porosity.

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