Construction Glossary

A failure or refusal to continue performance of a contract on a permanent basis, particularly by a contractor under a construction contract.

A remedy the common law provides for breaches of warranty in contracts for the sale of goods, work, and labour.

A spot height or level above the mean sea level. The level from which a measurement is taken.

The process whereby one substance permeates another by chemical or molecular action. Contrast with adsorption.

The part of a structure that bears the weight, thrust, or pressure of an arch, vault, or bridge by resisting horizontal and vertical forces.

An increase in the rate at which works are carried out, usually by applying additional resources to achieve an earlier completion date.

An admixture used to gain early strength in concrete by speeding up the chemical reaction between cement and water.

The unqualified agreement by the person to whom an offer is made, creating a binding contract. May be oral, in writing, or implied by conduct.

A floor located above the structural floor level that creates a space for mechanical and electrical services, including data and power cables.

Boards, panels, or tiles used on walls or ceilings to control or reduce sound, typically made of mineral-fibre, cork, or foam.

The real expenditure incurred in performing work. Also known as prime cost.

A document issued during the bidding process to modify, clarify, or supplement the original construction documents before contract execution.

Work beyond what was originally required under a construction contract, which may require a change order for additional payment.

A fire detection system in which each detector or sensor is wired back to a central control panel, reporting the precise location of activated devices.

A specially formulated additive that modifies the chemical and physical properties of concrete, mortar, or grout. Examples include plasticisers, retarders, and accelerators.

Physical conditions due to weather or artificial obstructions that could not have been reasonably foreseen and may entitle the contractor to an extension of time.

Acronym commonly used for "Architect and Engineer" or "Architecture and Engineering," referring to the design professionals on a project.

A designation on construction documents indicating they have been reviewed and approved for use in the field.

A granular material (typically crushed stone or sand) that forms an essential component of plaster, mortar, and concrete, providing compressive strength and cohesion.

A mechanical device used to condition and circulate air as part of an HVAC system. Typically contains filters, coils, fans, and dampers.

A formal instruction issued by the architect to the contractor during construction. Also refers to Approved Inspector in building control contexts.

A professional organization for architects in the United States. Publishes widely used standard form contracts for the construction industry.

A sum of money set aside in a contract to cover the cost of specific items not yet fully defined at the time of bidding.

Methods of resolving disputes outside of court litigation, including mediation, arbitration, and adjudication.

Revised construction drawings that reflect all changes made during the construction process, documenting the actual built conditions.

Written instructions from the architect that clarify or interpret the contract documents without changing the contract sum or time.

An international standards organization that develops technical standards for materials, products, systems, and services used in construction.

Material used to refill an excavation, or the process of refilling. Often uses compacted soil, gravel, or engineered fill.

A short pillar or column in a series supporting a rail, typically found in staircase railings and balconies.

A centralized system that controls and monitors a building's mechanical, electrical, and plumbing equipment including HVAC, lighting, and fire systems.

A wall that carries structural loads from above (floor, roof, or other walls) down to the foundation. Removal requires structural analysis and temporary support.

A fixed reference point of known elevation used in surveying and construction layout to establish vertical control.

A guarantee that the bidder will enter into the contract at the bid price if selected. Protects the owner against withdrawal of the bid.

A digital representation of the physical and functional characteristics of a building, used for design, coordination, and construction management.

Short pieces of wood or other material used to fill gaps, provide nailing surfaces, brace framing members, or support fixtures within wall cavities.

A document listing all materials, parts, and labour needed for a construction project, with quantities and unit costs for each item.

A boxed-in section of ceiling that conceals ductwork, plumbing, or structural elements. Also refers to a sloped door providing outside access to a basement.

Software used to create, modify, and optimize technical drawings and 2D/3D models of construction projects.

A slight upward curve built into a beam, truss, or slab to compensate for anticipated deflection under load.

A projecting beam or structure supported at only one end, with the other end extending unsupported into space.

A flexible sealant material used to fill gaps and joints in building construction to prevent air and water infiltration.

Regulations that set out health and safety responsibilities of clients, designers, and contractors throughout the lifecycle of a construction project.

A document issued by a local building authority confirming that a building complies with applicable codes and is safe for occupancy.

A written agreement modifying the contract documents, adjusting the contract sum, contract time, or both after the contract has been executed.

A recessed channel or groove in a wall, floor, or ceiling used to route pipes, wires, or ductwork.

The external covering or skin applied to a building's structure for weather protection and aesthetic appearance. Examples include metal panels, stone, and curtain walls.

The automated process of identifying conflicts between building systems in construction documents — such as ductwork intersecting structural beams — before construction begins.

A section of wall with windows that rises above an adjacent roofline, allowing natural light to enter interior spaces.

A precast concrete block used in construction. Available in standard, lightweight, and split-face varieties for structural and architectural applications.

A vertical structural member designed to transfer compressive loads from beams and slabs down to the foundation.

The systematic process of verifying that all building systems perform interactively according to the design intent and the owner's operational needs.

A composite material made from cement, water, sand, and aggregate that hardens over time. The most widely used construction material in the world.

The complete set of drawings and specifications used for construction, including architectural, structural, mechanical, electrical, and plumbing plans.

A review of construction documents by experienced builders to identify design elements that may be difficult, costly, or impossible to build as drawn.

A sum of money set aside in a budget to cover unforeseen costs or changes during construction. Typically 5-10% of the total construction cost.

A planned, weakened section in concrete or masonry designed to control the location of cracking caused by shrinkage and thermal movement.

A composite drawing overlaying multiple disciplines (structural, mechanical, electrical, plumbing) to identify spatial conflicts before construction.

The cap or covering on the top of a wall, designed to shed water and protect the wall from moisture infiltration.

A project scheduling technique that identifies the longest sequence of dependent tasks, determining the minimum project duration.

A non-structural outer covering of a building, typically consisting of aluminium frames with glass, metal, or stone panels. Transfers wind loads to the structural frame.

A barrier built into walls near ground level to prevent moisture from rising through the masonry by capillary action.

A sheet material laid under or within a floor construction to prevent moisture from passing through to the interior.

The permanent, static weight of the building structure itself, including walls, floors, roofs, and all permanently attached materials and fixtures.

The displacement or bending of a structural member under load. Design codes specify maximum allowable deflection ratios for beams and slabs.

A wall that separates two tenant spaces or a tenant space from a common area. Often required to meet specific fire-rating and sound transmission requirements.

A project delivery method in which a single entity provides both design and construction services under one contract.

The design phase following schematic design where the project's form, size, and materials are more precisely defined before construction documents are produced.

The hot water supply system in a building used for sinks, showers, and other plumbing fixtures — distinct from hydronic heating water.

An HVAC device mounted in ceilings or walls that distributes conditioned air evenly throughout a space. Common types include square, round, linear, and slot diffusers.

A vertical pipe that carries rainwater from the roof gutter system down to the ground or storm drainage system.

A legal right to use another party's land for a specific purpose, such as utility access, drainage, or a right-of-way.

The lower edge of a roof that overhangs the exterior wall, designed to direct water away from the building face.

White crystalline deposits that appear on masonry or concrete surfaces when water-soluble salts migrate to the surface and evaporate.

A means of exiting a building. Building codes regulate the number, width, and arrangement of egress paths based on occupancy type and occupant load.

A two-dimensional drawing showing a vertical view of a building face or interior wall, typically drawn to scale with material indications.

A gap or space in construction designed to accommodate thermal expansion and contraction of building materials, preventing cracking and structural damage.

A flat board or band running horizontally along the eaves of a roof, typically supporting the gutter system.

The elevation of the completed floor surface, including all finishes. A critical reference point for coordinating construction across disciplines.

The International Federation of Consulting Engineers, which publishes widely used standard form construction contracts identified by book colour (Red, Yellow, Silver, Gold).

A measure of how long a building element (wall, floor, door) can withstand fire exposure while maintaining its structural integrity, typically expressed in hours.

A material or assembly installed in openings and joints in fire-rated construction to prevent the spread of fire and smoke through concealed spaces.

Thin sheets of metal or other material installed at joints and transitions in construction to prevent water penetration.

The amount of time a non-critical activity can be delayed without affecting the project completion date in a CPM schedule.

The base of a foundation that spreads the structural load over a wider area of soil. Types include spread footings, strip footings, and mat foundations.

Temporary moulds or structures used to contain and shape poured concrete until it cures and achieves sufficient strength to support itself.

The primary contractor responsible for the overall construction of a project, who typically manages subcontractors and coordinates all field activities.

The process of shaping the ground surface to achieve desired elevations, drainage patterns, and site contours.

A fluid mixture of cement, water, and sometimes sand used to fill gaps, seal joints, and bond masonry units or tiles.

Heating, Ventilation, and Air Conditioning — the mechanical systems that control indoor temperature, humidity, and air quality in buildings.

A model building code developed by the International Code Council, widely adopted as the basis for building regulations across the United States.

The lowest point of the internal cross-section of a pipe or channel. Invert elevations are critical for ensuring proper drainage flow.

An international body that develops standards for quality management, environmental management, and other systems used in construction.

A horizontal structural member that supports a floor or ceiling, typically spaced at regular intervals and spanning between beams or bearing walls.

A measurable value used to evaluate the success of a project or process. Common construction KPIs include schedule variance, cost variance, and safety incident rates.

A pre-agreed daily or weekly sum payable by the contractor to the owner for each day of delay beyond the contractual completion date.

A project management approach focused on minimizing waste and maximizing value through collaborative planning, continuous improvement, and pull-based scheduling.

A horizontal structural element spanning an opening (door, window) that transfers the load above the opening to the adjacent wall structure.

The variable weight imposed on a structure by occupants, furniture, equipment, and other movable loads. Specified by building codes based on occupancy type.

A specification that defines the degree of detail and reliability of information within a BIM model element at various stages of design and construction.

Mechanical, Electrical, and Plumbing — the three major building systems that require coordination during design and construction.

Custom-fabricated woodwork including cabinets, trim, mouldings, and built-in furniture, typically produced in a mill or shop and installed on-site.

A full-size physical sample of a building element (e.g., curtain wall panel, brick veneer) built to verify quality, appearance, and constructability before full production.

A vertical or horizontal bar that divides the panes of a window or the panels of a curtain wall system.

A family of standard form construction contracts widely used internationally, known for plain language and collaborative project management approach.

A written authorization from the owner to the contractor to begin work, typically establishing the official start date for the contract time.

Manuals and documentation provided at project completion that describe how to operate and maintain all installed building systems.

A coordination meeting format involving the three primary project stakeholders to review progress, resolve issues, and make decisions.

A low wall or barrier at the edge of a roof, balcony, or terrace, providing fall protection and concealing rooftop equipment.

A notice identifying a potential change to the contract scope, cost, or time that has not yet been formally approved as a change order.

A surety bond guaranteeing that the contractor will complete the work according to the contract terms. Protects the owner if the contractor defaults.

A deep foundation element driven or drilled into the ground to transfer building loads through weak soil to stronger material or bedrock below.

The space between a suspended ceiling and the floor structure above, often used as a return air path for the HVAC system.

Concrete elements cast in a factory under controlled conditions, then transported and assembled on site. Offers higher quality control than site-cast concrete.

A list of incomplete or defective work items that must be corrected before a project can be considered substantially complete.

Systematic processes for ensuring construction work meets specified standards. QA focuses on preventing defects; QC focuses on identifying and correcting them.

Steel reinforcing bars embedded in concrete to provide tensile strength, compensating for concrete's weakness in tension.

A percentage of each progress payment withheld by the owner (typically 5-10%) as security for the contractor's completion of all work.

A formal document used to clarify design intent, resolve ambiguities, or request additional information about the construction documents.

A solicitation document inviting qualified firms to submit proposals for a project, including their approach, qualifications, and pricing.

A vertical pipe, duct, or conduit that carries utilities between floors of a building. Also refers to the vertical face of a stair step.

The initial design phase that establishes the general scope, scale, and relationships of a project's components through sketches and diagrams.

A drawing showing a vertical cut through a building or component, revealing interior construction, materials, and spatial relationships.

Detailed drawings prepared by contractors, subcontractors, or fabricators showing how specific components will be manufactured and installed.

Temporary structural support used during construction to hold up walls, floors, or excavation sides until permanent structure is in place.

A concrete floor slab poured directly on the ground, typically over a gravel base and vapour barrier. Common in single-storey commercial and industrial buildings.

The underside of a building element such as an arch, beam, staircase, or roof overhang.

Written instructions that describe the quality of materials, workmanship standards, and installation methods required for construction. Organized using CSI MasterFormat divisions.

The opaque area of a curtain wall between the top of one window and the bottom of the window above, typically concealing floor slabs and mechanical systems.

Product data, shop drawings, samples, or other documents provided by the contractor for the architect's review and approval before procurement or installation.

The stage when work is sufficiently complete that the owner can occupy and use the building for its intended purpose, even if minor items remain on the punchlist.

The portion of a building below ground level, including foundations, basement walls, and any below-grade construction.

The portion of a building above ground level, including the structural frame, floors, walls, and roof.

The process of measuring and listing all materials and quantities from construction drawings needed to estimate costs or place orders.

The point where new construction connects to an existing building system, utility, or structure.

A construction method where concrete wall panels are cast flat on the ground slab, then tilted up into position using a crane.

A certificate issued when the employer takes possession of the works, marking the transfer of care and responsibility from the contractor.

A systematic method of reviewing project design to achieve required functions at the lowest total cost without sacrificing quality or performance.

A material that resists the diffusion of moisture through building assemblies, preventing condensation within walls, roofs, and floor constructions.

An authorized departure from zoning or code requirements granted by a local authority, allowing construction that would otherwise be prohibited.

Small openings at the base of a masonry wall or retaining wall that allow trapped water to drain out, preventing hydrostatic pressure buildup.