RBSE Sec Voc Construction key terms

A workable mixture of cement or lime, sand, and water used to bind bricks or blocks and fill joints. Its strength and plasticity depend on the binder-to-sand ratio and curing.

The proportion by volume of cement to sand in a mortar or concrete mix, such as 1:4 or 1:6. Lower sand content gives stronger, leaner mortar; higher sand content gives weaker, more workable mixes.

A designation such as M20 that states the characteristic compressive strength of concrete in newtons per square millimetre at 28 days, tested on standard cubes.

Keeping fresh concrete or mortar moist and at a suitable temperature for a set period so cement hydrates fully and gains design strength. Ponding, wet covering, and plastic sheeting are common methods.

A compression test on 150 mm concrete cubes cast from a sample and cured for 7 or 28 days. Results check whether the delivered mix meets its specified grade.

A simple site test measuring how far a cone of fresh concrete settles when the mould is lifted. It indicates workability and consistency, not strength.

The mass of water divided by the mass of cement in a mix. Higher values improve workability but reduce strength and durability, so the ratio is capped by exposure conditions.

The pattern in which bricks are laid so that vertical joints do not align in successive courses. English, Flemish, and stretcher bonds distribute load and improve appearance and stability.

A single horizontal layer of bricks, blocks, or stone in a wall. Courses are kept level and plumb, and their height sets the module for openings and lintels.

A horizontal beam of timber, stone, or reinforced concrete spanning an opening such as a door or window to carry the wall above it.

A horizontal structural member carrying loads mainly in bending and transferring them to supports. It resists tension, compression, and shear along its span.

A vertical structural member carrying axial compression from beams, slabs, and walls down to the foundation. It is usually reinforced concrete, steel, or masonry.

The widened lowest part of a foundation that spreads the load of a column or wall over a larger soil area so bearing pressure stays within safe limits.

The maximum pressure soil can safely carry without excessive settlement or shear failure. It is determined by soil testing and governs footing size and type.

A continuous impervious layer, such as polythene or bitumen felt, built into a wall near ground level to stop moisture rising by capillary action into the structure.

The finished level of the floor at ground storey, measured above natural ground. It is a key reference for setting out, damp-proofing, and quantity measurement.

The fixed ratio between a distance on a drawing and the real distance it represents, such as 1:100. It is stated on the drawing and used with a scale rule.

A drawing showing a building or site as seen from directly above, cut at a stated level. It gives room sizes, wall thicknesses, openings, and layout dimensions.

An orthographic drawing of the external face of a building, showing heights, levels, openings, and finishes as viewed horizontally from one side.

A drawing showing the cut face of a building or component after an imaginary vertical plane passes through it, revealing internal construction, levels, and thicknesses.

The relative thickness of lines on a drawing. Thick lines show cut or structural elements, thin lines show dimensions, hatching, and hidden work, giving drawings hierarchy and clarity.

A thin line with arrowheads or ticks at its ends, placed between extension lines, on which a measurement is written to show the size of a drawn feature.

A tabulated list giving the bar mark, diameter, shape, cutting length, number, and weight of each reinforcement bar in an element, used for cutting and billing steel.

The systematic measurement of quantities of work from drawings, item by item, in the units used by the measurement rules, before rates are applied to build an estimate.

A priced or unpriced schedule listing measured items of work with descriptions and quantities, prepared from drawings so tenderers price the same scope on a common basis.

Working out the unit rate for an item from material, labour, plant, and overhead costs plus contractor profit, usually per cubic metre, square metre, or running metre.

A sum included in an estimate to cover unforeseen items or price changes during construction. It is not spent automatically but released only with approval.

A percentage deducted from each running bill and held by the client until completion or the defect liability period ends, protecting against defective work.

An interim payment claim submitted at intervals for work measured and completed since the previous bill, less deductions such as retention and mobilisation advance recovery.

A fixed, permanent point of known reduced level, often a marked concrete pillar or a chiselled mark on a wall, from which levels are transferred across a site.

The height of a point expressed relative to a chosen datum, usually mean sea level. Levels on site are calculated from staff readings and the bench mark value.

The surveying operation of finding differences in height between points using a level instrument and staff, so ground and finished levels can be set and checked.

Marking the exact position, alignment, and levels of walls, columns, and foundations on the ground from the drawings, using pegs, strings, and a baseline.

A measured perpendicular distance from a reference line or baseline to a feature such as a wall face or boundary, used to fix positions during setting out and surveying.

A straight reference line of known length and direction from which offsets and angles are measured to locate other points on a site or survey.

Wearable safety gear such as a helmet, safety boots, gloves, goggles, and high-visibility vest that reduces injury risk but does not remove the hazard itself.

A short, regular briefing by a supervisor on a specific hazard, safe method, or lesson learned, held at the workplace before work starts to refresh awareness.

A written document describing the sequence, plant, labour, and safety controls for a construction activity, prepared before work begins and followed on site.

A temporary working platform with standards, ledgers, and boards giving safe access and a place to work at height. It must be erected, tied, and inspected by competent persons.