ITI/NCVT Mason Building Constructor (AITT Theory) key terms

A brick wall bond in which one course consists entirely of stretchers and the next course entirely of headers, giving great strength and used for thick load-bearing walls.

A brick bonding pattern in which each course alternates headers and stretchers, producing an attractive face pattern often used for fair-faced external walls.

A brick laid lengthwise along the wall face so that its long side is visible, giving a 190 mm module in the wall length.

A brick laid with its short end facing the wall surface, used to tie the two leaves of a wall together and to close the bond across the thickness.

The corner brickwork of a wall, built with alternating header and stretcher bricks to form a strong, plumb external angle that guides the rest of the wall.

The layer of mortar between bricks or blocks that bonds them together, normally 10 mm thick and finished with a profile such as flush, weathered or recessed.

The stated proportion of cement, lime and sand by volume in a mortar, for example 1:1:6, which determines its strength, workability and suitability for the exposure conditions.

A paste made by slaking quicklime and soaking it in water, added to mortar to improve workability and water retention and to give some flexibility to the hardened joint.

The indentation formed in one bed face of a moulded brick; the brick is laid frog upward so the mortar fills the recess and forms a mechanical key.

A white powdery deposit of soluble salts that migrate to the surface of masonry and crystallise as the wall dries, usually caused by dampness and salt-bearing materials.

An impervious layer built into a wall near ground level, such as polythene or bitumen felt, that stops ground moisture rising into the masonry above by capillary action.

A continuous sheet or coating, for example bituminous felt or liquid-applied polymer, applied to a surface to prevent water penetration into roofs, basements or wet areas.

The process of transferring the building lines, levels and dimensions from the drawings onto the ground before excavation, using pegs, profiles and a line.

A surveying instrument with a fixed telescope and spirit level, mounted on a tripod, used with a levelling staff to take reduced levels and transfer heights on site.

The height of a point expressed relative to a chosen datum, calculated by adding backsight readings and subtracting foresight readings in a level book.

A pointed weight hung on a cord to give a true vertical line, used to check the plumbness of walls, columns and the verticality of formwork and door frames.

A tool containing a sealed vial of liquid with an air bubble that indicates whether a surface is horizontal or vertical, available in lengths from 600 mm to 1.8 m.

A flat steel hand tool with a handle, used by masons to pick up and spread mortar, tap bricks into position and finish plaster surfaces.

A flat tool with a wooden, cork or steel face used to level and compact plaster or screed, and the steel version to give a smooth finished surface.

A quick-setting gypsum plaster made by heating gypsum, used for small repair patches, mouldings and decorative work where fast setting is required.

The process of raking out and refilling the outer part of mortar joints with a fresh, often richer mix, to improve weather resistance and appearance of the masonry face.

Keeping concrete or mortar moist and at a suitable temperature after placing so that cement hydration continues, typically for seven days for ordinary Portland cement work.

A workability test in which fresh concrete is placed in a standard cone, the cone is lifted, and the amount the concrete settles is measured in millimetres.

The mass of water divided by the mass of cement in a concrete mix; a lower ratio increases strength and durability but reduces workability.

A continuous concrete footing of uniform width and depth running under a load-bearing wall, transferring the wall load to the ground at a safe bearing pressure.

A large reinforced concrete slab covering the whole footprint of a building, used where soil bearing capacity is low or loads are heavy and differential settlement must be limited.

A horizontal structural member of concrete, steel or timber spanning an opening in a wall to carry the masonry above it and transfer the load to the piers each side.

A curved structure that spans an opening and carries load mainly in compression, transferring it through its voussoirs to the abutments or piers on either side.

Temporary timber or steel framework that supports an arch or slab during construction and is struck, that is removed, once the masonry or concrete has gained sufficient strength.

The vertical side face of an opening in a wall, between the outer face of the wall and the frame, often finished with plaster or a reveal lining.

The vertical height and horizontal going of a single stair step; the riser plus tread relationship, often around 2R + T = 600 mm, governs comfortable stair design.

A thin layer of cement-sand mortar laid over a concrete floor slab to provide a smooth, level surface to receive the final floor finish.

A strip of timber, tile or PVC fixed at the base of an internal wall to protect the plaster from damage and to conceal the joint between wall and floor.

A tabulated list giving the bar mark, diameter, shape, length, number and bending dimensions of each reinforcement bar in a concrete member, used for cutting and fixing steel.

Temporary moulds of timber, plywood or steel, with their supports, that hold fresh concrete in the required shape until it has hardened enough to be self-supporting.

A recessed panel formed in a ceiling, soffit or arch, often decorative, produced by a grid of beams or ribs in concrete, plaster or timber.

The systematic measurement and listing of quantities of work from drawings, following a standard method of measurement, to prepare a bill of quantities.

A priced or unpriced document listing measured items of work with descriptions and quantities, forming the basis for tendering and for valuing variations during construction.

Items worn by a worker to reduce risk of injury, such as a hard hat, safety boots, gloves, eye protection and high-visibility clothing, selected for the task hazards.

A short, informal safety briefing given to the work crew at the start of a shift to discuss specific hazards, controls and safe methods for the day's tasks.

A temporary working platform of tubes, couplers and boards erected to give safe access and a working place at height for bricklaying, plastering and finishing trades.