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BTEB Masonry practice questions

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Question 1Masonry (trade theory and practical)

What is the standard nominal face size of a common modular clay brick used in masonry construction?

  1. 230 mm × 110 mm × 76 mm
  2. 215 mm × 102.5 mm × 65 mm Correct answer.
  3. 200 mm × 100 mm × 75 mm
  4. 190 mm × 90 mm × 57 mm

Explanation

A standard UK clay brick has a work size of 215 mm long by 102.5 mm wide by 65 mm high, giving a coordinating size of 225 × 112.5 × 75 mm once a 10 mm joint is added. The 65 mm height plus the joint produces the familiar four courses per 300 mm module.

Question 2Masonry (trade theory and practical)

Which mortar designation is the strongest mix covered by common masonry specification and is used for heavily loaded or damp-exposed brickwork?

  1. Designation (iv)
  2. Designation (i) Correct answer.
  3. Designation (ii)
  4. Designation (iii)

Explanation

Mortar designations run from (i) the strongest to (iv) the weakest in the traditional British classification. Designation (i) has the highest cement content and is reserved for high-stress or severe-exposure situations. Weaker designations are chosen where flexibility and movement tolerance matter more than compressive strength.

Question 3Masonry (trade theory and practical)

In a stretcher bond wall, how much does each brick overlap the brick below it?

  1. The full brick length
  2. One quarter of a brick length
  3. One third of a brick length
  4. Half of a brick length Correct answer.

Explanation

Stretcher bond places bricks lengthwise along the wall face with each course offset by half a brick from the course beneath. This half-brick overlap distributes load and prevents continuous vertical joints. It is the simplest and most common bonding pattern for half-brick thick walls.

Question 4Masonry (trade theory and practical)

Why is a brick dampened before being laid in very dry, hot weather?

  1. To improve the colour match between adjacent bricks
  2. To make the brick heavier and more stable on the line
  3. To reduce the amount of mortar needed in the joint
  4. To stop the brick absorbing water from the mortar too quickly Correct answer.

Explanation

Dry bricks draw water rapidly out of fresh mortar, leaving it weak, crumbly and poorly bonded. Slight wetting of the brick reduces this suction so the mortar can cure properly. The aim is a damp surface, not a saturated brick, since excess water causes slumping.

Question 5Masonry (trade theory and practical)

What is the main purpose of a wall tie in a cavity wall?

  1. To carry the vertical load of the inner leaf
  2. To act as a damp-proof course across the cavity
  3. To provide a fixing for roof trusses
  4. To transfer wind load between the two leaves and hold them together Correct answer.

Explanation

Wall ties connect the outer and inner leaves so that wind pressure on the outer skin is shared with the stiffer inner leaf. They also stop the leaves spreading apart. Ties must be installed at the specified spacing and with a slight fall towards the outer leaf to shed any moisture.

Question 6Masonry (trade theory and practical)

Which tool is used to check that a course of brickwork is truly horizontal along its length?

  1. A plumb rule
  2. A bolster chisel
  3. A gauge rod
  4. A spirit level Correct answer.

Explanation

A spirit level placed on the brickwork shows whether the course is level along its length and, when held vertically, whether the face is plumb. It is the basic instrument for controlling both horizontality and verticality. A gauge rod controls course heights rather than levelness.

Question 7Masonry (trade theory and practical)

What does the term 'frog' refer to on a clay brick?

  1. A decorative raised pattern on the stretcher face
  2. A coloured surface stain from the kiln
  3. A recessed indentation formed in one bed face Correct answer.
  4. A hairline crack caused by firing

Explanation

Many clay bricks are moulded with a shallow depression called a frog in one bed face, which reduces weight and helps key the mortar. Frogged bricks are normally laid frog uppermost unless the specification says otherwise. The frog should be filled with mortar during laying.

Question 8Masonry (trade theory and practical)

What is the minimum lap required when building blockwork in stretcher bond with standard blocks?

  1. One full block length
  2. 50 mm
  3. 100 mm Correct answer.
  4. Half the block length

Explanation

Concrete blockwork is normally laid to a minimum lap of 100 mm, which is a quarter of a standard 440 mm block length. This lap avoids continuous vertical joints while allowing the common quarter-bond setting out. Where the lap falls below the minimum, a bond may need to be adjusted or a cutting schedule planned.

Question 9Masonry (trade theory and practical)

A wall is 10 m long and 2.4 m high, built in half-brick (102.5 mm) stretcher bond. Using 60 bricks per square metre, how many bricks are required, ignoring wastage?

  1. 1680 bricks
  2. 1440 bricks Correct answer.
  3. 1800 bricks
  4. 1200 bricks

Explanation

The wall area is 10 m × 2.4 m = 24 m². At 60 bricks per square metre for a half-brick wall, the total is 24 × 60 = 1440 bricks. A wastage allowance is normally added on top of this figure for cutting and breakage.

Question 10Masonry (trade theory and practical)

Which type of joint finish sheds rainwater most effectively on an exposed external wall?

  1. Weathered joint Correct answer.
  2. Recessed joint
  3. Bucket-handle joint
  4. Flush joint

Explanation

A weathered joint is struck at an angle so that the mortar slopes outward and downward, allowing water to run off the face. This reduces the chance of water sitting on the joint and penetrating. Recessed and flush joints both tend to trap or hold water on the face.

Question 11Masonry (trade theory and practical)

What is the primary function of a damp-proof course in a solid masonry wall?

  1. To allow the wall to expand thermally
  2. To bond the wall to the foundation concrete
  3. To stop moisture rising by capillary action from the ground Correct answer.
  4. To provide a key for internal plaster

Explanation

A damp-proof course is a continuous impervious layer placed near the base of the wall to interrupt capillary rise of ground moisture. It must be lapped with any damp-proof membrane in the floor and remain unbroken around the perimeter. Bedding and jointing must not bridge the membrane.

Question 12Masonry (trade theory and practical)

When building a corner, which technique best ensures the two faces stay square to each other?

  1. Building the corner first and using a 3-4-5 check or square Correct answer.
  2. Relying on the string line alone
  3. Checking squareness only after the wall reaches window height
  4. Laying each face independently and joining them at the end

Explanation

Corners are built up first as a guide, then checked for square using the 3-4-5 triangle method or a large square. The string lines are then run between the established corners so the intervening wall follows true. Racking back from a built corner keeps the bond correct.

Question 13Masonry (trade theory and practical)

Why must a toothed or racked-back joint be limited in height at the end of a day's work?

  1. To keep the wall within the height of the scaffold
  2. To reduce the amount of mortar used
  3. To prevent the unsupported end being damaged or blown over Correct answer.
  4. To allow the bricks to be reused the next day

Explanation

A toothed end leaves individual bricks projecting without support from the adjoining work. If the step is too high, the projecting bricks can be knocked off or the end can become unstable in wind. Limiting the racking height keeps the unfinished end safe until work resumes.

Question 14Masonry (trade theory and practical)

What is the purpose of a movement joint in a long masonry wall?

  1. To separate different mortar designations
  2. To allow the wall to be dismantled in sections
  3. To accommodate expansion and contraction without cracking Correct answer.
  4. To provide a fixing point for wall ties

Explanation

Masonry expands and contracts with temperature and moisture changes, and long panels need a controlled break to absorb that movement. A movement joint is built with a compressible filler and a sealant so the wall can move without random cracking. It also breaks the continuity of the wall ties and any reinforcement.

Question 15Masonry (trade theory and practical)

A bricklayer needs to build a 1.5-brick thick wall. Which bonding arrangement is most appropriate for strength and appearance?

  1. English bond Correct answer.
  2. Flemish garden wall bond
  3. Stack bond
  4. Stretcher bond throughout

Explanation

English bond alternates a course of stretchers with a course of headers, giving good longitudinal and transverse strength in thick walls. For walls over one brick thick it is a traditional and reliable choice. Stretcher bond alone cannot tie the thickness of a thick wall together.

Question 16Masonry (trade theory and practical)

What is the correct order of operations when preparing to lay the first course on a concrete foundation?

  1. Spread mortar, lay the first brick at the corner, then check level and square
  2. Lay all bricks dry, then lift them and butter the joints individually
  3. Mark the wall position, establish corners, lay the first course to line and level Correct answer.
  4. Set out the gauge rod, then build the first course without checking level

Explanation

Setting out comes first: the wall position is marked and the corners established and checked for square. The first course is then laid to line and level, with the gauge rod controlling course heights. Getting the first course accurate prevents errors accumulating up the wall.

Question 17Masonry (trade theory and practical)

Why is a lime-based mortar often preferred for repointing historic soft brickwork?

  1. It sets faster and allows earlier finishing
  2. It is more flexible and allows moisture to evaporate from the wall Correct answer.
  3. It is cheaper than any cement-based mix
  4. It is stronger than cement mortar and resists frost better

Explanation

Old soft bricks are weaker and more porous than modern ones, so a strong rigid cement mortar can trap moisture and cause the brick face to spall. A lime-rich mortar is weaker and more permeable, letting the wall breathe and accommodating slight movement. Repointing should match the original mortar's strength and composition.

Question 18Masonry (trade theory and practical)

What is the effect of using too wet a mortar mix when laying bricks?

  1. The mortar gains strength because it flows into every joint
  2. The bricks absorb more water and bond more tightly
  3. The bricks become easier to level but the mortar loses strength and the wall may slump Correct answer.
  4. The finished joints are more weather-resistant

Explanation

Excess water makes the mortar easy to spread but reduces its final strength and increases shrinkage. Wet mortar also causes bricks to float and the wall to slump out of line. The mix should be workable but stiff enough to support the bricks without settlement.

Question 19Masonry (trade theory and practical)

Which component is used to anchor a masonry veneer to a steel stud backup wall?

  1. A corrugated wall tie fixed to the studs Correct answer.
  2. A reinforcing bar cast into the foundation
  3. A damp-proof course
  4. A movement joint filler

Explanation

Veneer ties are fixed to the backup framing and embedded in the masonry so the veneer is restrained against wind and seismic loads. Corrugated or wire ties are common for this purpose. The tie must be installed with the correct embedment and slope to shed water.

Question 20Masonry (trade theory and practical)

What is the purpose of a 'soldier course' in a brick wall?

  1. To tie two leaves of a cavity wall together
  2. To provide a decorative band of bricks laid on end Correct answer.
  3. To support the lintel over an opening
  4. To form a damp-proof course at the base

Explanation

A soldier course consists of bricks laid on end with their stretcher faces showing, producing a tall narrow decorative band. It is often used above openings or as a string course. Because the bricks are on end, the course needs careful support and should not be relied on for structural spanning.

Question 21Masonry (trade theory and practical)

A 4.5 m long wall is built in a clay brick with a coefficient of thermal expansion of 0.000006 per °C. If the temperature range is 40 °C, what is the approximate movement?

  1. 0.54 mm
  2. 2.16 mm
  3. 1.08 mm Correct answer.
  4. 4.32 mm

Explanation

Movement equals length × coefficient × temperature change, so 4500 mm × 0.000006 × 40 = 1.08 mm. This small figure shows why movement joints in brickwork are spaced generously rather than at every metre. The calculation is used to decide joint spacing and sealant capacity.

Question 22Masonry (trade theory and practical)

Why is it important to avoid continuous vertical joints in load-bearing masonry?

  1. They make the wall difficult to plaster
  2. They prevent the wall from accommodating movement
  3. They increase the amount of mortar required
  4. They create planes of weakness that reduce structural integrity Correct answer.

Explanation

Continuous vertical joints align the weaker mortar joints through several courses, forming a plane along which the wall can crack or split under load. Bonding patterns offset the joints so each brick is supported by the two below. This is why stack bond is restricted to non-structural or reinforced applications.

Question 23Masonry (trade theory and practical)

What is the principal reason for specifying a weaker mortar than the masonry unit it bonds?

  1. To allow slight movement and enable the mortar to fail before the brick Correct answer.
  2. To reduce the cost of the mortar
  3. To speed up construction by allowing earlier loading
  4. To improve the appearance of the finished joints

Explanation

Mortar should be weaker and more permeable than the units so that any movement or moisture damage occurs in the joint, which is easier to repair. A mortar stronger than the brick can cause the brick face to spall. This principle underlies the matching of mortar designation to unit strength.

Question 24Masonry (trade theory and practical)

In a cavity wall, why must wall ties be installed with a slight fall towards the outer leaf?

  1. To ensure any water reaching the tie drips outward rather than inward Correct answer.
  2. To increase the tensile capacity of the tie
  3. To allow for thermal expansion of the tie
  4. To allow the tie to be driven in more easily

Explanation

Moisture can reach ties through the outer leaf, and a tie sloping down towards the inner leaf would carry water into the cavity and potentially to the inner skin. A slight outward fall lets water drip off before it crosses the cavity. Ties must also be kept clear of mortar droppings at the base of the cavity.

Question 25Masonry (trade theory and practical)

A bricklayer is building a wall in Flemish bond and finds the face pattern drifting out of alignment. What is the most likely cause?

  1. Incorrect setting out of the alternating header and stretcher positions Correct answer.
  2. Failing to wet the bricks before laying
  3. Using too strong a mortar mix
  4. Using a gauge rod with the wrong course height

Explanation

Flemish bond alternates headers and stretchers in every course, so the pattern depends on precise setting out of the first course. If the header and stretcher positions are not established correctly, the pattern drifts and cannot be corrected later. A gauge rod controls height, not the horizontal pattern.

Question 26Masonry (trade theory and practical)

Which mortar joint thickness is generally recommended for standard clay brickwork so that the units and mortar act together effectively?

  1. About 40 mm
  2. About 3 mm
  3. About 25 mm
  4. About 10 mm Correct answer.

Explanation

A joint of roughly 10 mm is the accepted standard because it is thick enough to accommodate slight variations in unit size and to develop a good bond, yet thin enough that the mortar does not shrink excessively or lose strength. Thicker beds reduce compressive strength and increase settlement, while very thin joints make it hard to level and plumb the work. Consistent joint thickness also keeps courses at the designed height.

Question 27Masonry (trade theory and practical)

Which sand characteristic is most important for producing a workable, strong mortar?

  1. A high proportion of clay and silt
  2. Well graded particles from coarse down to fine Correct answer.
  3. Uniformly single-sized fine grains
  4. Angular grains of one coarse size only

Explanation

A well graded sand contains a range of particle sizes so the smaller grains fill the voids between the larger ones, giving a dense mortar that needs less cement paste and is both workable and strong. Single-sized or poorly graded sands leave high void content and produce harsh or lean mixes. Excess clay and silt increase shrinkage and reduce strength.

Question 28Masonry (trade theory and practical)

What is the standard nominal size of a concrete block used in general blockwork?

  1. 300 mm x 150 mm x 75 mm
  2. 390 mm x 190 mm x 190 mm
  3. 440 mm x 215 mm x 100 mm Correct answer.
  4. 600 mm x 300 mm x 150 mm

Explanation

The common concrete block has a nominal face of 440 mm by 215 mm, which with a 10 mm joint makes a module of 450 mm by 225 mm, and a thickness of 100 mm. This module suits bonding and setting out on a simple grid. Other sizes exist, but the 440 x 215 x 100 block is the standard general-purpose unit.

Question 29Masonry (trade theory and practical)

Which type of mortar is made by mixing cement, lime and sand with water?

  1. Resin adhesive
  2. Gypsum plaster
  3. Cement-lime mortar Correct answer.
  4. Bituminous mastic

Explanation

Cement-lime mortar combines cement for strength, lime for workability and water retention, and sand as the fine aggregate. The lime improves plasticity and helps the mortar retain water so it bonds well to absorbent units. Gypsum, resin and bitumen are used for other purposes and are not masonry bedding mortars.

Question 30Masonry (trade theory and practical)

What is the main purpose of building a masonry wall with a cavity between two leaves?

  1. To make the wall cheaper by using fewer ties
  2. To increase the dead load on the foundation
  3. To allow the wall to be built without mortar
  4. To reduce rain penetration to the inner leaf Correct answer.

Explanation

The cavity forms a break in the path that water would otherwise take through the wall, so any rain that passes the outer leaf drains down the cavity and out through weep holes. This keeps the inner leaf dry and improves thermal performance. The cavity is not a structural or cost-saving device and does not remove the need for mortar or ties.

Question 31Masonry (trade theory and practical)

Which tool is used to spread and shape mortar and to tap bricks into position when laying?

  1. A bolster chisel
  2. A club hammer
  3. A trowel Correct answer.
  4. A line pin

Explanation

The bricklayer's trowel is the main hand tool for picking up, spreading and trimming mortar and for tapping units to level. It has a flat diamond-shaped blade and a handle designed for control. A bolster, club hammer and line pin serve cutting, striking and line-holding functions rather than mortar placement.

Question 32Masonry (trade theory and practical)

Why is the mason's line kept taut when laying a course of bricks?

  1. To give a straight, level reference for the course Correct answer.
  2. To increase the strength of the mortar
  3. To prevent the wall from expanding thermally
  4. To stop the bricks from absorbing water

Explanation

A taut line stretched between pins provides a straight, level datum that the bricklayer works to, so each unit is laid to the same plane and the course stays true. A slack line sags and produces a wavy, uneven wall. The line has no effect on suction, mortar strength or thermal movement.

Question 33Masonry (trade theory and practical)

Which action best protects freshly built masonry from rapid drying in hot, windy weather?

  1. Adding more cement to the mix
  2. Covering the work and damping it down Correct answer.
  3. Leaving it fully exposed to the sun
  4. Laying the bricks dry

Explanation

Rapid evaporation removes the water the cement needs to hydrate, so the mortar never reaches full strength and may crumble. Covering the wall and lightly damping it keeps the mortar moist while it cures. Extra cement and dry bricks both worsen the problem rather than solve it.

Question 34Masonry (trade theory and practical)

A wall is to be built 6 m long and 2.7 m high in stretcher bond using standard bricks at 60 bricks per square metre. How many bricks are required, ignoring wastage?

  1. 648
  2. 1620
  3. 486
  4. 972 Correct answer.

Explanation

The wall area is 6 m multiplied by 2.7 m, which equals 16.2 square metres. Multiplying by 60 bricks per square metre gives 972 bricks. Allowance for cutting and breakage would then be added on top of this figure.

Question 35Masonry (trade theory and practical)

What is the effect on a mortar mix of increasing the proportion of lime relative to cement?

  1. Improved workability with lower compressive strength Correct answer.
  2. Faster setting with reduced water retention
  3. Higher compressive strength with reduced workability
  4. Complete loss of adhesion to the masonry units

Explanation

Lime makes a mortar more plastic and easier to spread, and it improves water retention, but lime is weaker than cement so increasing its share lowers the final compressive strength. The mix must therefore be chosen to suit the exposure and loading. It does not speed setting or destroy adhesion.

Question 36Masonry (trade theory and practical)

Why are bricks usually wetted before laying in hot weather when a strong mortar is used?

  1. To reduce suction so the mortar retains its water Correct answer.
  2. To increase the bricks' compressive strength
  3. To prevent the bricks from staining the mortar
  4. To make the bricks heavier and more stable

Explanation

Very dry, highly absorbent bricks pull water out of the mortar, leaving it too dry to hydrate and bond. Damping the units reduces this suction so the mortar keeps enough water to cure and grip. Wetting does not change the strength of the brick or its weight in any useful way.

Question 37Masonry (trade theory and practical)

In English bond, what pattern of alternating courses is produced?

  1. All courses of headers
  2. All courses of stretchers with random headers
  3. Two stretchers to one header in every course
  4. One course of headers to one course of stretchers Correct answer.

Explanation

English bond alternates a full course of headers with a full course of stretchers, giving very strong, easily controlled work. The header course ties the two leaves or thicknesses together, while the stretcher course gives the face appearance. Flemish bond and stretcher bond use different arrangements.

Question 38Masonry (trade theory and practical)

Why should a wall tie in a cavity wall be bedded into the mortar of both leaves rather than nailed to the inner leaf?

  1. To transfer lateral load and allow slight movement between leaves Correct answer.
  2. To reduce the number of ties required
  3. To make the cavity wider at the top
  4. To prevent the outer leaf from being built

Explanation

Ties must be securely bedded in both leaves so that wind load on the outer leaf is transferred to the structural inner leaf, while the tie's shape allows minor differential movement. Fixing only to the inner leaf or nailing leaves the outer leaf unrestrained. Ties do not control cavity width or the number needed.

Question 39Masonry (trade theory and practical)

What is the purpose of a lintel over an opening in a masonry wall?

  1. To act as a damp-proof course above the opening
  2. To allow the wall to expand at the opening
  3. To provide a decorative band across the wall
  4. To carry the masonry above the opening and transfer load to the sides Correct answer.

Explanation

A lintel spans the opening and supports the wall above it, transferring that load to the masonry on either side. It must be strong and stiff enough to carry the load without excessive deflection. It is a structural element, not a decorative, damp-proofing or movement provision.

Question 40Masonry (trade theory and practical)

Which of these is the correct way to store bricks on site before use?

  1. Stacked on edge in the sun to dry out
  2. Stored in water-filled tanks
  3. Piled in loose heaps on soft ground
  4. Stacked level on a firm base and covered to keep them dry Correct answer.

Explanation

Bricks should be stacked level on a firm, drained base and protected from rain so that their moisture content and suction stay consistent. Loose heaps on soft ground cause chipping and settlement, and soaking or over-drying changes suction and bond. Consistent storage gives predictable laying behaviour.

Question 41Masonry (trade theory and practical)

What is the main reason for raking out mortar joints before repointing an old wall?

  1. To remove the damp-proof course
  2. To expose sound masonry and give the new mortar a key Correct answer.
  3. To widen the joints for decoration
  4. To make the wall lighter

Explanation

Raking out removes decayed or loose mortar and exposes sound faces of the units so the new mortar can bond and form a mechanical key. It also lets the repair mortar be compacted into the joint. Decorative widening, weight reduction and DPC removal are not the purpose.

Question 42Masonry (trade theory and practical)

A bricklayer is setting out a rectangular building and checks the diagonals of the base. What does equal diagonal measurement confirm?

  1. That the foundation is watertight
  2. That the walls are level
  3. That the courses are plumb
  4. That the corners are square Correct answer.

Explanation

If the two diagonals of a rectangle are equal, the figure is a true rectangle and its corners are therefore square. This is a basic setting-out check before walls are built. Diagonals say nothing about level, watertightness or plumbness, which need separate checks.

Question 43Masonry (trade theory and practical)

Which factor most directly determines the required spacing of movement joints in a clay brick wall?

  1. The number of courses in the wall
  2. The type of trowel used
  3. The coefficient of thermal expansion and expected temperature range Correct answer.
  4. The colour of the bricks

Explanation

Movement joints are placed to accommodate the expansion or contraction that results from temperature change, so the coefficient of thermal expansion and the design temperature range are the key inputs. Moisture movement of the units also matters. Brick colour, tools and course count do not set joint spacing.

Question 44Masonry (trade theory and practical)

What is the correct way to cut a brick neatly with a bolster chisel and club hammer?

  1. Soak the brick first, then snap it by hand
  2. Break the brick over the knee
  3. Strike one face only without scoring
  4. Score a line around all faces, then strike firmly on the line Correct answer.

Explanation

Scoring a continuous line around all faces creates a weak plane so that the brick breaks cleanly along the intended line when struck. Striking a single unscored face gives a ragged, uncontrolled break. Bricks are too strong to snap by hand even when wet.

Question 45Masonry (trade theory and practical)

Why is a fair-faced or facing bond often specified for the external leaf of a wall?

  1. To eliminate the need for a foundation
  2. To give a controlled, attractive face pattern on the exposed side Correct answer.
  3. To allow the wall to be built without a DPC
  4. To reduce the number of wall ties needed

Explanation

Facing bonds are chosen so that the visible face shows a regular, deliberate pattern of stretchers and headers, which is the aesthetic requirement for exposed work. The bond must still be structurally sound. It does not change tie requirements, foundation design or damp-proofing.

Question 46Masonry (trade theory and practical)

A cavity wall is to be built with a 100 mm cavity and 100 mm blocks. Which wall-tie length is most appropriate?

  1. About 225 mm Correct answer.
  2. About 150 mm
  3. About 100 mm
  4. About 400 mm

Explanation

The tie must embed sufficiently in both leaves and span the cavity, so the length equals the two embedment depths plus the cavity width. With a 100 mm cavity and roughly 50 to 60 mm embedment each side, a tie of about 225 mm is required. Shorter ties would not reach both leaves, and a 400 mm tie would be excessive.

Question 47Masonry (trade theory and practical)

Why is a stepped foundation often used on a sloping site?

  1. To keep the foundation base on suitable bearing strata while limiting excavation Correct answer.
  2. To reduce the height of the building
  3. To provide a decorative feature at the base
  4. To make the wall above easier to paint

Explanation

On sloping ground the foundation is stepped so that each section bears on competent soil at the required depth, avoiding excessive excavation on the high side. The steps are formed in increments that suit the masonry above. Appearance, painting and building height are not the reasons.

Question 48Masonry (trade theory and practical)

A long free-standing garden wall of clay brick shows a vertical crack at regular intervals. Which explanation is most likely?

  1. Incorrect brick colour selection
  2. Excessive foundation depth
  3. Use of too many wall ties
  4. Thermal expansion not accommodated by movement joints Correct answer.

Explanation

Clay brickwork expands with temperature and moisture, and a long unrestrained wall will crack at regular intervals unless movement joints are provided. The crack pattern is characteristic of expansion being forced into a confined length. Foundation depth, ties and colour do not produce this regular vertical cracking.

Question 49Masonry (trade theory and practical)

Why is the compressive strength of masonry generally lower than the compressive strength of the individual units?

  1. Bricks shrink after laying
  2. Wall ties pull the units apart
  3. Mortar is weaker and joints introduce planes of lower strength Correct answer.
  4. The DPC carries the vertical load

Explanation

Masonry is a composite of strong units and weaker mortar, and the horizontal joints form planes where stress concentrates and lateral tension develops, so the assembly fails at a lower stress than the units alone. The relative stiffness of unit and mortar also affects the failure mode. Units do not shrink in a way that explains this, and ties and DPCs are not the load path.

Question 50Masonry (trade theory and practical)

When repointing a wall built with soft, old bricks, why should a strong cement-rich mortar be avoided?

  1. It sets too slowly to be practical
  2. It cannot be applied with a trowel
  3. It is less permeable and stiffer, so moisture and stress concentrate in the brick Correct answer.
  4. It reacts chemically with all bricks

Explanation

Old soft bricks are relatively permeable and flexible, so a hard, impermeable cement mortar traps moisture behind the joint and is stiffer than the brick, causing stress to concentrate in the units and leading to spalling and cracking. A weaker lime-rich mortar matches the brick's movement and allows moisture to escape. Setting speed, trowel workability and universal chemical reaction are not the reasons.