Sri Lanka NVQ L3 Mason cheat sheet

Minimum PPE for masonry work: hard hat, safety boots, high-visibility vest, eye protection when cutting, gloves for mortar work and a dust mask for dusty tasks.

Cutting concrete, block or stone with a dry power saw releases respirable crystalline silica; control it with wet suppression or on-tool extraction plus a suitable respirator.

Hearing protection is required from 85 dB(A) averaged over an eight-hour day; masonry cutters, grinders and mixers commonly exceed this level.

Wet cement and mortar are strongly alkaline (about pH 12-13) and cause dermatitis and chemical burns; wash skin immediately and wear gloves and long sleeves.

Scaffold working platform: top guardrail about 1.0 m high, mid rail about 0.5 m, plus toe boards and a fully boarded platform.

Ladder rule: set at 1 in 4 (about 75 degrees), tie it off, and extend it at least 1 m above the landing point.

Manual handling: keep the load close to the body, bend the knees, and use two or more persons for heavy stone or dense blocks.

Excavations deeper than 1.2 m need shoring or safe battering, and spoil or materials are kept at least 1 m back from the edge.

Cement and lime dust irritate eyes and airways; eyewash must be available on site and bags opened carefully in ventilated areas.

Store cement bags on pallets at least 150 mm above the floor in a dry, ventilated store; keep stacks stable and low and issue oldest stock first.

Place sand and coarse aggregate on hard, drained surfaces in separate bays with dividing walls so the materials and sizes never mix.

Stack bricks and blocks on level ground to a stable height, commonly not more than about 1.8 m, clear of scaffold legs and traffic routes.

Locate the mixing platform and water point close to the work, on firm level ground, so mortar is not carried long distances.

Confirm the position of buried water, electricity and telephone services from drawings or the utility owner before digging, and hand-dig near marks.

Provide a firm, drained access route for deliveries and barrows; barrow ramps should not be steeper than about 1 in 12.

Cut a fall in the ground away from mixing areas so water drains off and does not pond under the mortar board.

Set out the site store, first aid point, toilet, waste skips and fire point, and keep walkways and escape routes clear at all times.

3:4:5 method: measure 3 units on one line and 4 on the other, then adjust until the diagonal reads 5 units; any multiple such as 6:8:10 gives a right angle.

Set corner pegs and profiles beyond the excavation line, offset from the wall face by a known dimension, and stretch string lines between them.

With a dumpy level, set up roughly equidistant from backsight and foresight so collimation error cancels out.

Height of instrument (HI) = reduced level of benchmark + backsight; reduced level of a point = HI minus foresight.

Change point rule: the last foresight of one instrument setup becomes the backsight of the next setup.

For a rectangular building, both diagonals must measure the same; correct each corner by half the difference until they agree.

Transfer the datum upwards with a tape and straightedge or a laser, and check each storey height against a storey rod.

Check verticality with a plumb bob or spirit level, and check each course with a line and line level before laying continues.

Check any laser level against a known benchmark before use, because an out-of-adjustment instrument repeats the same error everywhere.

Brick trowel for laying and spreading mortar, pointing trowel for finishing joints, wood or steel float for render, hawk for holding mortar.

Bolster chisel with a club hammer cuts bricks and blocks; point, scutch and comb chisels dress stone.

Test a spirit level by reading it on a flat surface, reversing it end for end and comparing; the bubble must read the same both ways.

A standard builder's wheelbarrow holds about 60-70 litres (0.06-0.07 m3); count barrow loads when batching or moving concrete.

Slings, chains and lifting accessories must carry a marked safe working load, be inspected before each lift and never be overloaded.

Never put hands, trowels or shovels into a rotating mixer drum; isolate the power before cleaning or maintenance.

Brick tongs carry six to ten bricks and should be used instead of passing bricks hand to hand at height.

Clean mortar off tools before it sets and lightly oil steel surfaces; a set mortar film ruins a trowel edge and a level face.

Store chisels, blades and power tools in a dry store; sharpen chisel edges at the correct bevel and replace cracked handles.

Mortar by volume: 1:3 is strong, 1:4 to 1:5 is general purpose, 1:6 is weaker; lime or a plasticiser improves workability.

Use one gauge box or bucket for every batch so the cement:sand ratio stays constant; proportions are by volume unless weight batching is specified.

Concrete water-cement ratio is typically 0.4 to 0.6; adding extra water increases slump but lowers strength and causes bleeding.

Typical volume mixes: C20 about 1:2:4 and C25 about 1:1.5:3 cement:fine aggregate:coarse aggregate.

Mix the dry ingredients until the colour is uniform, add water and mix for 2-3 minutes; machine mixing gives a more consistent result.

Use cement mortar within about two hours of mixing, or about one hour in hot weather; do not revive stiffened mortar with extra water.

The slump test measures workability in millimetres; 150 mm cubes cured and crushed at 28 days measure compressive strength.

Sand must be clean, sharp and free of clay and organic matter; damp sand bulks, so volume batching must allow for it.

Grout for filling hollow block cores is a wet, high-slump cement mix placed to fill the voids and bond any reinforcement.

Standard bed and cross joints are about 10 mm thick, kept within 8-12 mm; thick joints reduce strength and increase shrinkage.

Bonds: stretcher, English (alternate header and stretcher courses) and Flemish (alternate header and stretcher in the same course); minimum overlap is one-quarter brick.

Header courses at quoins are finished with quarter closers so the bond closes correctly at the corner.

Limit each day's lift to about 1.2-1.5 m of wall height, and leave unfinished ends as stepped racking rather than vertical toothing.

Hollow block walls normally use 1:4 or 1:5 mortar; fill cores with grout where the specification requires it.

Cavity walls need wall ties at the specified spacing, commonly 900 mm horizontally and 450 mm vertically, with weep holes at the base.

Check plumb and level at every course with a spirit level, and use a storey rod to control course heights and opening sizes.

Do not lay masonry on a soft, saturated or dirty base, because the mortar will not bond and the wall will settle unevenly.

Protect new masonry from rapid drying and do not load green walls with stored materials or scaffolding ties.

Rubble types: random (uncoursed), coursed and polygonal; ashlar is squared, dressed stone laid in regular courses.

Lay every stone on its natural bed - the plane in which it formed in the quarry - for maximum strength and weather resistance.

Break the joints: no continuous vertical joint should run through two or more courses.

Place through stones or bond stones across the full wall thickness every 1 to 1.5 m in both directions to tie the faces together.

Pack hearting (small chips) into the wall core well bedded in mortar; loose filling leaves voids and weakens the wall.

Use a stiff 1:3 to 1:4 cement mortar that supports the stones without flowing out of the joints.

Retaining walls need a batter on the face, a wider base, weep holes and back drainage so water pressure cannot build up.

Check line, level and plumb with string and spirit level, and check face batter against a template as the wall rises.

Dress stone with point, scutch and boaster chisels, and wear goggles because dressing throws sharp chips.

Internal plaster is normally 10-15 mm thick in two coats; external render is 15-20 mm in two coats, each coat about 8-12 mm.

Mix internal plaster about 1:3 to 1:4 cement:sand (or cement:lime:sand); external render about 1:4 to 1:6 with a plasticiser or waterproofer.

Apply a scratch coat about 8-10 mm thick and comb or scratch it to form a key before the next coat.

Control suction by damping absorbent blockwork; on dense concrete use a bonding agent or spatterdash coat.

Fix corner beads and cover joints between different backgrounds with scrim or tape to prevent cracking.

Keep new plaster and render damp for about seven days; rapid drying causes shrinkage cracks and dusty surfaces.

A wood float gives a textured finish; a steel trowel gives a smooth, dense, polished finish.

Fit drip beads and bell mouths at the plinth and over openings so water is thrown clear of the wall.

Efflorescence is soluble salt deposited on the surface; brush it off dry, find the water source, and never wash it back in.

Measure lengths in metres, areas in square metres and volumes in cubic metres; describe work clearly in the bill of quantities.

Deduct openings larger than the stated limit, commonly 0.5 square metres, from masonry and plaster areas; smaller openings are not deducted.

One 50 kg cement bag has a loose volume of about 0.035 cubic metres, so roughly 28-30 bags make one cubic metre of loose cement.

Allow about 5-10 percent extra material for breakage, cutting and spillage; blocks, bricks and tiles need more than cement or sand.

Concrete cubes of 150 mm are cured and tested at 7 and 28 days; the 7-day strength is typically about 65-70 percent of the 28-day value.

Record deliveries, batch dates, slump and cube results, and inspection requests in the site diary as work proceeds.

Check level, plumb and dimensional tolerance against the specification at each stage and record any deviation before it is covered up.

Keep a snag list and obtain written sign-off before covering work that will later be hidden, such as wall ties or damp proof course.

Hold a toolbox talk before work starts: state the task, the hazards, the controls and the PPE, and allow questions.

Read and follow the method statement and risk assessment; any change to the method needs supervisor approval first.

Report all accidents, near misses and dangerous occurrences promptly and make sure they are written in the site record.

Use one agreed signaller and standard hand signals with crane or hoist operators; nobody else gives signals.

Give short, clear instructions and confirm understanding by asking the worker to repeat the task back.

Escalate safety or quality problems beyond your authority to the supervisor; never improvise on a safety control.

Coordinate with other trades before chasing or cutting, and check for embedded services and finished work.

Keep the site diary, labour returns and material records accurate so the supervisor can plan and claim correctly.

Resolve disagreements privately and respectfully; refer repeated or serious issues to the supervisor rather than letting them affect work.