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Abandonment Of Work

To leave site and refuse to continue work. Must entail a complete stoppage of work with a clear intention not to continue or complete the work. The term is often used in arbitration and adjudication and marks a point where reference to legal proceedings can commence.

Abatement Of Action

An interruption of legal proceedings. A party, normally the defendant, serves an application of abatement giving reasons why proceedings should not continue.

Above Grade

A higher elevation than ground level. See also above ground level.

Abram’s Law

Rule that states the strength of concrete (or mortar) is inversely related to the water/cement (w/c) ratio. Provided there is sufficient water to ensure that the *hydration reaction occurs, the lower the water/cement ratio, the higher the strength of the concrete/mortar.


The wearing away of one material against another by friction.

Abrupt Wave

An unexpected increase in flow caused by a sudden change in flow conditions.


The horizontal or x-coordinate within the Cartesian coordinate system.

Abseil Survey

An inspection undertaken on a tall building/structure by a qualified person suspended via a rope.

Absorption Rate

The rate of water absorption, ingress by capillary action, into a material when exposed to a water medium over a period of time.


A solid structure, usually a pier or wall, which provides support to an arch, bridge, or vault. It enables the loads from the structure to be transmitted to the *foundations. 2. The point where a roof slope intersects a wall that extends above the roof slope. 3. The intersection between two building elements. 4. In dam construction, the sides of the valley against which the dam is constructed.

Abutment Flashing

A flashing at an abutment, usually made from lead, although copper and mortar have been used.

Accelerated Weathering

Normally a cyclic process that simulates adverse climatic conditions (such as temperature, ultraviolet radiation, and moisture), which is used to assess the durability of materials.


A measure of the rate at which velocity is changing, i.e. a change in speed over time.


An admixture that enhances early strength (hardening) but the long-term strength remains unaffected. Regularly used in cold weather when urgent repair work is needed. Calcium chloride is the most common accelerator, however, it reduces corrosion protection.

Access Floor

A floor that is suspended above the structural floor. Usually consists of removable panels supported on a metal grid that is raised off the floor by adjustable pedestals or battens. The space between the two floors can be used to route various services such as data, telephone, power, lighting, heating and cooling pipes, and ventilation.

Accordion Door

A door comprising a number of sections that fold together like the bellows of an accordion when opened.

Acoustic Board

A board used on walls, floors, and ceilings that is designed to improve sound absorption or sound insulation.

Acoustic Clip

A clip that is attached to the floor joists to provide support for an acoustic floor. Used to reduce impact sound transmission on floating timber floors.

Acoustic Construction

Any type of construction that improves the acoustics of the construction. For instance, reduces sound transmission, improves sound insulation, or increases sound absorption.

Acoustic Lining

A lining material that is designed to absorb noise and reduce sound transmission. Used on pipes and ductwork.


A branch of physics that relates to the study of sound generation, sound transmission, absorption, and reflection.


An area of land equal to 4840 square yards (0.405 hectares).

Acrylic Paints

A type of paint in an acrylic polymer emulsion renowned for its quick drying properties.

Active Earth Pressure

The horizontal pressure that is exerted on a retaining wall by the mass of soil it retains. Active pressure develops when the wall moves away from the retained mass and the soil expands sufficiently to mobilize its shear strength. The minimum horizontal stress (pa) occurs when the failure strength of the soil is fully mobilized, represented by the minor principal stress, and is calculated by multiplying the coefficient of active earth pressure (Ka) by the vertical stress at the point of consideration.

Active Fire Protection

A fire protection system that uses electrical and/or mechanical equipment to detect or suppress fires, such as fire detectors, alarms, sprinklers, or spray systems. They require regular maintenance to ensure that they are fully operational.


A mechanical device that is used to convert electrical, hydraulic, or pneumatic energy into mechanical energy. Used in flow control valves, meters, motors, pumps, switches, and relays.

Acute Angle

An angle that is greater than zero degrees but less than 90°. In an acute angle triangle all three angles are acute.


A substance that is added to another to alter (normally improve) properties or performance, e.g. an admixture to concrete.


A process whereby the molecules of two separate substances cling together to form a bond.


A substance used to bond two objects or materials together.

Adjoining Property

A building that has a common boundary or is attached to another property.

Adjustable Steel Prop

A steel support that is adjustable along its length. Used to provide vertical support to floors and temporary beams.


A chemical product which is added to concrete (<5% by mass) during mixing or by additional mixing, prior to placing, such that the normal concrete properties are changed, e.g. the speed of strength development, improvement of permeability, protection from fungicidal attack, improvement in workability.


A building material made from water, sand, and soil containing clay that is dried in the sun. Straw or other organic fibrous materials may be added to reduce cracking, aid drying, and to help bind the material together. An adobe brick, or mud brick, is made by placing adobe into a mould.


The accumulation of a substance (gas or liquid) on a surface of another substance (liquid or solid), forming a molecular film.

Adverse Weather Conditions

Weather conditions that restrict or preclude work from being undertaken on site, such as high winds and heavy rain.


The introduction of air (or gas) into a substance (e.g. water, concrete, sewage).


The study of airflow around objects and the movement of objects through air, with particular reference to the forces experienced by an object as a result of the movement of air.

A-Frame Building

A triangular-shaped building with a steeply sloping roof that extends to ground level.


A small earthquake, normally one of many, that occurs after a large earthquake.


Granular material used in concrete, road construction, mortars, and plaster. Aggregates can originate from natural rocks, gravel and sands (e.g. limestone and sandstone), formed from artificial sources (via a thermal process), or be recycled inorganic construction waste.

Aggregate Cement Ratio

Weight of aggregate divided by the weight of cement.

Air Brick

A brick containing a series of holes that run through the brick to allow ventilation. Usually built into a wall to ventilate rooms or a space under a ground floor level. Available in a range of different sizes.


A low-density porous material extensively utilized in the construction industry, usually in block form. The air content (porosity) is typically between 60% and 85%. It is produced by mixing cement and/or pulverized fuel ash, lime, sand, water, and aluminium powder.

Air Drain

An empty space left around the external perimeter of a foundation to prevent moisture from the surrounding ground causing dampness.

Air-Entrained Concrete

A type of concrete with purposely incorporated minute air bubbles to improve its freeze–thaw resistance.

Air-Entraining Agent

An admixture which causes minute air bubbles to be incorporated into concrete, used to improve workability and frost resistance.

Air Infiltration

The uncontrolled exchange of air into a building through a wide range of air leakage paths in the building envelope.

Air-Inflated Structure

An air-inflated structure has a double membrane supported by a series of tubes that are inflated using high pressure air. Air-supported structures have a single membrane that is supported by low pressure air. Both types of structures can be rapidly erected or dismantled and are mainly used as temporary structures.


A metallic material comprising two or more elements that can be either a metal or non-metal. Any metal that is not 100% pure is classified as an alloy. Examples of alloys are steel, stainless steel, galvanized steel, cast iron (all based on iron), bronze, brass (both based on copper), and solder (a mixture of lead and tin). The primary objective of alloys is to obtain a metal which comprises a mixture of the main attributes of each constituent.


Sediments (silt, sand, gravel, etc.) deposited by flowing water (rivers and streams).


A non-ferrous metal/alloy, chemical formula Al. Aluminium has the merit of being light (density 2,700 kg/m3 as compared to 7,900 kg/m3 for steel), ductile, and easily rolled into sheets and thin strips, and extruded into complex sections. It resists corrosion, especially if it is anodized.

Aluminium-Zinc Coating

Anti-corrosion treatment of metal-coated steel. An aluminium-zinc alloy coating applied to steel provides enhanced corrosion protection and can improve the lifetime of steel by up to four times that of galvanized steel under the same conditions.


The immediate surrounding area. The ambient conditions, i.e. air temperature, wind speed, and humidity, can be defined for a given location.

Anchor Block

A block of wood set within a masonry wall, in place of a brick, that provides a surface for connecting other wooden items.

Anchor Plate

A plate attached to a component that enables other components to be connected to it.

Angle Bead

A perforated metal strip in the shape of an angle that is used to protect and reinforce the corner of a plaster or plasterboard wall. The perforations are used to nail the strip to the surrounding plaster or plasterboard and act as a key when the bead is plastered over.

Angle Brace

A brace fixed across an interior angle in a frame to improve the frame’s rigidity. The brace can be temporary or permanent.

Angle Cleat

A short L-shaped angle used to connect components to structural members, e.g. attaching pre-cast concrete cladding panels to the main structural frame, or purlins to roof trusses.

Angle of Repose

The steepest angle a granular heap of material would make to the horizontal when poured.


Having different properties in different directions. Timber is anisotropic because it is stronger loaded in the direction of the grain rather than *perpendicular to the grain.


A heat treatment applied to materials, especially metals, to alter the chemistry, hence mechanical properties.

Anodic Protection

A process utilizing electrolysis to improve the corrosion resistance of metals.


A process using electrolysis to coat a metal with a protective film.


An estimate of value. For a property it could be the current market value for insurance purposes or functional value for business purposes. 2. Staff appraisals identify how a person has performed, whether existing goals have been met, whether he or she has established new business targets and areas of personal and *professional development.


A horizontal piece of trim inserted underneath a window-sill on the inside. The tarmac or concrete area at an airport where aircraft stand when not in use.


A water-yielding strata. Permeable rock, sand, or gravel through which groundwater flows. The water can be extracted through a well dug down into the aquifer.


A curved structure that is designed to span an opening and support weight. Many different types of arches exist, varying in shape and style.

Arch Dam

A curved water-retaining structure. The arch action is used in the horizontal plane to withstand water *pressure, which is transferred to the abutments.

Architectural Drawings

Drawings produced by the architect that provide a detailed image of the proposed building.

Architectural Ironmongery

Decorative or ornamental products made from iron or other metals, such as banisters, screens, and railings.

Architectural Sections

Details that cut through the building to show how the components fit together within the building.


The science, art, or field of study associated with the construction, detail, style, and aesthetics of buildings.

Arc Welding

An inexpensive and widely used welding process, it involves an electric arc to melt the metals at the melting point. Sometimes the welding region is protected by an inert gas.

Artificial Seasoning

An improved method of preventing bowing, cupping, twisting, or springing of boards or planks of lumber. During the latter portion of the timber-drying schedule, the boards or planks are passed between spaced pairs of rollers arranged to hold the lumber in a fixed plane. The lumber is therefore held in this plane while it is setting. Preferably the drying schedule includes intermittent exposure of the lumber to microwave radiation in an electronic kiln dryer.

As-Built Drawing

Drawings that show how a building has been constructed; the true position of service. Such information is essential for the safe maintenance and operation of the building.


A material comprised mainly of bitumen, sand, clay, and limestone. Used in road construction.

Asphalt Soil Stabilization

The addition of asphalt to soil to improve its properties, i.e. reduce *permeability and increase *bearing capacity.


The joining of the components that make up the final structure.

At Rest Earth Pressure

The in-situ stress state of a soil where no horizontal or vertical strains occur. The ratio of horizontal stress (s0 H) to vertical stress (s0 v) is denoted by Ko, the coefficient of earth pressure at rest.


A tall internal courtyard spanning a number of floors that has a glazed roof.

Atterberg Limits

The physical properties of a fine-grained cohesive soil is normally directly related to its water content. There are four states in which the soil can exist, the boundaries between these states are known as the consistency limits.


A space in the roof that can be converted into a habitable room.


A screw-shaped tool used to cut into wood or soil to produce a hole. The tools used to extract soil can be hand-held or mounted on tracked vehicles.

Automatic Level

An optical instrument used for *levelling. Prisms within the instrument ensure that a horizontal line of *collimation will pass through the cross-hairs, provided that the instrument is approximately level.


A sudden mass movement of snow down a mountainside.

Award of Tender

Notification by the client or nominated body of acceptance of tender. Acceptance of the tender normally leads to the signing of the contract and binding agreement. Acceptance of the tender (offer) is normally a contract in itself; however, the finalities of the agreement are often negotiated after the tender has been accepted.


An external covering that projects out from a building to provide protection from the sun and rain and is usually retractable.


The horizontal angle, in degrees, from true north to a point directly beneath an observed object, e.g. the compass bearing of a star.

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