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

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.

What is 'retempering' of mortar and what are the rules for doing it?

Retempering is adding a little water to mortar that has stiffened through evaporation, to restore workability. It is only acceptable to replace water lost by evaporation and only before the cement has begun to set; mortar that has started to set (typically older than about two hours) must be discarded, not retempered.

Why should mortar generally be used within about two hours of mixing?

Once the cement begins hydrating it sets and develops strength. Using mortar after it has started to set gives weak, poorly bonded joints. As a rule of thumb mortar should be used within roughly two hours of mixing, and never retempered once it has begun to stiffen from setting rather than evaporation.

Compare hand mixing and machine mixing of mortar.

Hand mixing (board and shovel) suits small quantities and gives the bricklayer direct control but is labour-intensive and less consistent. Machine (drum or pan/paddle) mixing gives a more uniform, thoroughly blended mortar quickly for larger volumes, but materials must be batched accurately and the mixer cleaned out before set.

What precautions are taken when bricklaying in COLD weather (near or below freezing)?

Do not lay on frozen surfaces or when temperatures are at/below freezing; protect new work and materials from frost with insulation/sheeting; use unfrozen materials (warm the water/sand if needed); avoid water-rich mixes; and never use chloride accelerators near metal. Stop work if the temperature is falling below about $2$–$3\,^{\circ}\text{C}$.

What precautions are taken when bricklaying in HOT or drying weather?

Hot, dry or windy conditions cause rapid water loss, poor hydration and weak bond. Dampen (do not soak) absorbent bricks, keep materials shaded, use retarders if needed, cover/cure finished work to retain moisture, and avoid mixing more mortar than can be used before it stiffens.

Name the main types of trowel a bricklayer uses and their purposes.

Brick (laying) trowel for spreading and shaping mortar beds and buttering; pointing trowel (small) for filling and finishing joints and tucking in mortar; and a margin/gauging trowel for mixing small amounts and pointing tight areas.

What are jointing tools used for and name common joint profiles they form?

Jointers (jointing irons) compress and finish mortar joints to shed water and improve appearance. Common profiles include the bucket-handle (concave) joint, weather-struck joint, recessed joint and flush joint; the concave and weathered profiles best resist rain penetration.

What is the bricklayer's line and pins used for?

The line is a taut string stretched between line pins (or corner blocks) set into the perpends of the leads/quoins. It gives an accurate horizontal reference so each course is laid level, straight and to the correct height between the built-up corners.

How does a spirit level work and what does it check?

A spirit level uses a sealed vial of liquid containing a bubble; the bubble centres between the marks when the tool is truly horizontal (level) or vertical (plumb). Bricklayers use it to check that courses are level, faces are plumb, and to transfer levels along the work.

What is a gauge rod (storey rod) and why is it used?

A gauge rod is a straight timber/aluminium staff marked with the course spacing (e.g. every $75\,\text{mm}$) and key heights such as DPC, sill, lintel and floor levels. Held against the work it lets the bricklayer keep every course to the correct gauge and check heights consistently.

What are profiles (corner/wall profiles) used for in setting out?

Profiles are temporary corner/end posts (timber boards or proprietary metal profiles) set up plumb at the ends of a wall, marked to gauge, with the line attached between them. They let bricklayers build straight, plumb walls to gauge without first building brick leads/quoins.

What is a boat level and when is it used?

A boat level is a small, short spirit level (often around $230\,\text{mm}$) used for levelling and plumbing in confined spaces — small returns, blockwork details, pipework or door/window reveals — where a full-length level will not fit.

Describe the bolster and lump (club) hammer cutting method for bricks.

The brick is marked, then a bolster (a wide, flat masonry chisel) is held on the cutting line and struck with a lump (club) hammer to score and split the brick along the line. It gives a controlled cut; the rough face is dressed with the brick hammer/comb.

What is a disc cutter and what safety precautions does its use require?

A disc cutter is a powered angle grinder/cut-off saw with an abrasive or diamond blade for accurate cutting of bricks, blocks and pavers. It creates harmful silica dust and noise, so it requires water suppression or dust extraction, RPE (FFP3 mask), eye protection, ear defenders, gloves and the correct blade and guard.

Why should masonry cutting with a disc cutter be carried out wet (water-fed) where possible?

Dry cutting masonry releases respirable crystalline silica dust, which causes silicosis and lung disease. Water suppression (on-tool water feed) binds the dust at source, drastically reducing airborne silica and protecting the operative and others nearby.

What routine inspection and maintenance keeps hand tools safe and effective?

Before use check tools for damage: secure, unsplit handles; sharp, true edges on trowels/bolsters; no 'mushroomed' striking heads on chisels/hammers; clean, set-free trowel blades; and intact spirit-level vials. Clean tools after use, dry them to prevent rust, and store them safely off the ground.

How should tools be stored to preserve their accuracy and life?

Clean off mortar (especially from trowel blades and levels) before it sets, dry metal tools to prevent corrosion, keep cutting edges protected, store spirit levels flat or hung to avoid distortion, and lock power tools away with cables/blades inspected. Damaged tools are repaired or replaced, not used.

What is the purpose of wall ties in a cavity wall?

Wall ties bridge the cavity to connect the inner and outer leaves so they act together structurally, resisting wind loads and keeping the leaves correctly spaced, while their shape stops water from crossing the cavity from outer to inner leaf.

What are the typical spacing requirements for wall ties in a cavity wall?

Ties are usually spaced at a maximum of $900\,\text{mm}$ horizontally and $450\,\text{mm}$ vertically (about $2.5$ ties per $\text{m}^2$). At openings, movement joints and the verticals of reveals they are placed closer — typically within $225\,\text{mm}$ of the edge and at maximum $300\,\text{mm}$ vertical centres.

What is the minimum embedment of a wall tie into each leaf and how should it be set?

Each tie should be embedded at least $50\,\text{mm}$ into the mortar bed of each leaf. It must be laid level or with any slope/drip falling toward the outer leaf and the drip pointing downward, so water cannot track across to the inner leaf, and bedded clean of mortar droppings.

What is a damp-proof course (DPC) and where is it positioned in a wall?

A DPC is an impervious horizontal barrier (e.g. polymer/bitumen-polymer sheet, or engineering-brick/slate courses) built into the brickwork to stop rising damp. It is placed at least $150\,\text{mm}$ above finished external ground level and below the timber/floor it protects, and links to the DPM in the floor.

What is the difference between a DPC and a DPM?

A damp-proof course (DPC) is the horizontal/vertical barrier in walls preventing rising or penetrating damp in masonry; a damp-proof membrane (DPM) is a continuous sheet (e.g. polythene) in/under a floor slab preventing ground moisture rising through the floor. The two are lapped and sealed together to form a continuous barrier.

Why is the DPC set a minimum of 150 mm above external ground level?

The $150\,\text{mm}$ (two-brick-course) minimum prevents rain splash-back, surface water and ground moisture from bridging over the top of the DPC into the wall above, which would defeat the barrier and cause dampness in the inner wall.

What is a cavity tray and where is it required?

A cavity tray is a DPC formed across the cavity, sloping from the inner leaf up-and-over to the outer leaf, that collects any water in the cavity and directs it out through weep holes. It is required wherever the cavity is bridged or interrupted — above lintels/openings, at abutments, roof junctions and where the cavity stops.

What are weep vents (weep holes) and how are they spaced?

Weep vents are open perpend joints (often with plastic weep inserts) at the base of a cavity tray that let water collected on the tray drain to the outside. They are normally spaced at a maximum of $450\,\text{mm}$ centres, with at least two over each opening.

What is the function of a stop end on a cavity tray?

A stop end is an upturned closure formed at each end of a cavity tray. It prevents water running off the end of the tray into the cavity or down into the wall, forcing collected water to discharge through the weep holes instead.

What is a lintel and what is its structural job over an opening?

A lintel is a beam (steel, precast concrete or reinforced masonry) spanning a door or window opening. It carries the loads from the masonry and structure above and transfers them to the masonry either side of the opening, keeping the wall above the opening supported.

What is a padstone and when is one needed?

A padstone is a hard, load-spreading block (e.g. dense concrete or engineering brick) bedded under the bearing end of a heavily loaded beam or lintel. It spreads the concentrated point load over a larger area of masonry to prevent the brick/block beneath from being crushed.

How is masonry reinforced for tension, and what is bed-joint reinforcement (mesh)?

Masonry is weak in tension, so steel is added: vertical/horizontal bars in reinforced masonry, or bed-joint reinforcement — a stainless or galvanised steel mesh/ladder laid in the mortar bed. Bed-joint mesh controls cracking, distributes loads, strengthens over openings and helps resist lateral/movement stresses.

What minimum end bearing does a lintel normally require on the supporting masonry?

A lintel typically requires a minimum end bearing of about $150\,\text{mm}$ onto solid, level masonry (sometimes $100\,\text{mm}$ for short spans per manufacturer data), bedded on full mortar so the load is transferred properly and the lintel cannot slip or overstress the bearing.

Contrast full-fill and partial-fill cavity wall insulation.

Full-fill insulation (e.g. mineral-wool batts or blown fibre/beads) completely fills the cavity, maximising insulation for a given width but relying on good workmanship to keep it dry. Partial-fill insulation (rigid boards clipped to the inner leaf) leaves a clear residual air gap (typically at least $50\,\text{mm}$) on the outer side to keep moisture away from the inner leaf.

Why must a clear residual cavity be maintained with partial-fill insulation boards?

The retained clear gap (usually a minimum of $50\,\text{mm}$) between the insulation board and the outer leaf prevents rainwater that penetrates the outer leaf from crossing the cavity to the inner leaf. Mortar droppings and snots must be kept off the boards and ties so the gap stays clear and the wall remains dry.