Construction Glossary

If you're overwhelmed by the complexity and volume of construction terms, use our guide to learn how to break them down, understand, and use them.

Glossary terms

3-week look ahead: The schedule that is published each week by the general contractor that outlines what is occurring in the next three weeks of the project. This is broken down into small, actionable tasks, as opposed to the main project schedule (which is the overall timeline).

Abutment: Supporting structure at each end of a single span bridge. Types of abutments vary based on geotechnical, geographic, and constructability factors.

Actuator: A device operated either electrically, pneumatically, or hydraulically that acts as a motor to change the position of movable devices such as valves or dampers.

Addendum: Any documentation (drawings, specifications, etc.) issued during the bidding process to modify, clarify, or complement the information outlined in the bidding documents. Addenda become part of the contract documents upon awarding of the contract to a firm.

As-builts: The common term for marked up floor plans (usually in red ink) showing how installation differed from the original design drawings. As-builts are usually created for utilities and in-wall systems that aren’t directly visible. The formal term for as-builts is record drawings.

Back charge: A charge against a contractor’s contract for costs incurred by another party that should have been incurred by the contractor. A back charge typically takes form in a deductive change order. For example, if the contractor in charge of fire sprinklers damaged a wall using a boom lift, that contractor may incur a back charge from the drywall contractor for the repair work.

Backfilling: This is to refill excavated trenches or holes with the material dug out of it.

Beam: A sturdy piece of timber or metal, usually horizontal, with a main function to support loads such as the roof or floor above.

Bid: A binding offer made by a contractor to do the scope of work specified in the bidding documents at a certain price. This offer must be in accordance with the plans and specifications of the project and the terms and conditions stated in the offer.

Building automation system (BAS): An energy management system, usually with additional capabilities, relating to the overall operation of the building in which it is installed; this includes equipment monitoring, protection of equipment against power failure, and building security. It's the digital automation that takes operation of an HVAC design out of someone’s physical hands and moves it onto a computer interface.

Building management system (BMS): An energy management system relating to the overall operation of the building in which it is installed. It often has additional capabilities, such as equipment monitoring, protection of equipment against power failure, and building security. It may also be a direct digital control (DDC) system where the mode of control uses digital outputs to control processes or elements directly.

Bulletins: The new drawings or specifications that are issued (usually by the architect or lead designer) to the contractor after its contract award. These may be a result of RFIs, an owner’s request, errors/omissions, or a reviewing agency request.

Cantilever: A beam which is securely supported at one end, and hangs freely at the other, like balconies that have no pillars or columns supporting them.

Change order (CO): A change to the original contract scope of work, resulting in either an increase or decrease in project costs and/or schedule. This could be issued by a client to the general contractor or the general contractor to a subcontractor.

Clear and grub: The process of removing vegetation and material from land in the construction area. This prepares the site for excavation and grading work to take place.

Close out: A phase that encompasses the end of a project. This consists of punch lists, O&M manuals, as-builts/record drawings, warranties, and the overall completion of project work.

Cofferdam: A structural enclosure installed to retain water in damp soil or bodies of water. The cofferdam is installed and water is pumped out of the enclosure to provide a dry and safe work environment.

Commissioning: The process of testing and verifying the intended behavior of the building systems, such as HVAC, plumbing, electrical, life safety, lighting, etc. This is generally conducted by the contractor in tandem with the facility management team in order to ensure that the building staff are prepared to operate and maintain its systems and equipment.

Computer-Based System: A management system in which a computer is the central controlling device.

Construction daily reports (CDR): A record of field notes, including work completed, weather conditions, and materials delivered or used on-site.

Contingencies: The cost provisions in the project budget that make allowance for oversights and unforeseen circumstances associated with the project. Depending on the nature of the contract, the contractor may require owner’s approval to draw funds from contingencies.

Contract drawings: The conformed set of drawings that represents the entire contract scope.

Core & shell: A term that refers to the base construction of a building. This includes its structure, cladding, and vertical systems, such as MEP utility risers, stairs, and elevators, as well as its finished common areas, such as lobby and restrooms.

Critical lift: Per OSHA 1926.751, a lift that (1) exceeds 75% of the rated capacity of the crane or derrick, or (2) requires the use of more than one crane or derrick.

Damp-proof course: Usually abbreviated as DPC, this is a watertight layer applied to masonry to prevent moisture rising up from the ground.

Datum: Also known as datum point, this refers to any elevation taken as a reference point for leveling.

Derrick barge: Also known as a crane barge. These floating cranes lift large loads while on water. These are great for offshore construction use.

Direct digital control (DDC): A type of control where controlled and monitored analog or binary data (e.g., temperature, contact closures) are converted to digital format for manipulation and calculations by a digital computer or micro-processor, then converted back to analog or binary form to control physical devices.

DLB (dig, lay, bury/backfill): Term used in underground construction that describes the activity of utility installation. Dig/excavate dirt, lay your utility line, and backfill.

Embankment: An elevated landmass made of compacted soil or aggregate. Embankments help create roads and level surfaces for slabs or levees.

Energy management system (EMS): A system of computer applications used by building engineering staff to monitor, control, and optimize the building's operating performance (e.g., energy consumption, occupant comfort levels). EMS optimizes building operating performance through supervisory control programs that utilize core BMS functionality. An EMS is a more refined definition of a building management system (BMS) focused exclusively on operating performance with things like indoor air quality (IAQ), occupant productivity and comfort, and energy output as key metrics.

Falsework: These are the temporary structures that are built to hold and support cast-in-place concrete during pours and while it cures to strength.

Field order: A work order issued to a contractor by the owner or general contractor to perform work not included in the contract. The contractor will then be entitled to a change order for the extra work. Field orders are used to expedite work in an emergency or crucial situation, when there is no time to compile and approve a change order request.

Fit out: A term that refers to the interior construction of a building to make it suitable for occupation. This could include distribution of MEP services, ceiling systems, finishes, furniture, lighting, etc.

Grade and compact: The process of leveling out an area of land and exerting force using heavy equipment to stabilize the soil or aggregate.

Hip roof: A roof where all four sides slope down towards the walls.

HVAC: The equipment, terminals, and distribution systems that provide, either collectively or individually, the processes of heating, ventilating, or air conditioning to a building or portion of a building. Basically, the setup of machines that make a room or space warmer, cooler, or more conditioned in some regard.

HVAC Zone: A space or group of spaces within a building with heating, cooling, and ventilating requirements that are sufficiently similar so that desired conditions (e.g., temperature) can be maintained throughout using a single sensor (e.g., thermostat or temperature sensor).

IR: This stands for "inspection request" which is a form required by independent third-party inspectors to confirm an installation detail or method. It is often used for work such as welding, anchoring, and concrete pours.

Kip: A unit of force or weight, equal to 1,000 pounds, used to measure engineering loads.

K-rail/Jersey barrier: A precast concrete barrier that comes in 10’ or 20’ lengths. These are used to separate traffic, protect traffic from a leading edge, or designate the construction zone.

Liquidated damages: An amount of money that the contractor would owe the owner in the event of a breach of contract. These are typically calculated by a formula such as $10,000 per day of substantial delay of completion.

MSE (mechanically stabilized earth) wall: A wall system consisting of vertical panels and horizontal straps backfilled with aggregate or soil. MSE walls allow for easier and quicker installation than traditional cast-in-place methods.

OAC meeting: A meeting held at a scheduled time (generally weekly or biweekly) between the owner, the architect, and the general contractor. This meeting covers general project management topics, such as safety, scheduling, procurement, RFIs, submittals, change orders, design changes, etc. The general contractor is usually responsible for leading the meeting and distributing the meeting minutes.

O&M manual: This stands for operations and maintenance manual which is an instruction guide to running and servicing a building. The O&M manual is given to the owner at turnover.

Pile: Usually, a long structural member driven into the ground to act as support for a foundation or wall. There are many forms of pile that differ by material, shape, and size.

PPE: This stands for "personal protective equipment" which is basically the proper attire for a construction job. Such equipment often includes a hard hat, hard-soled boots, reflective vest, safety glasses, long pants, and a shirt with at least 6” long sleeves.

Post-tensioning: A method for prestressing (strengthening) concrete whereby cables are pulled or the concrete is jacked up after it has been placed.

Preliminary notice: Documents notifying other parties that they are working on the project. They’re often required to preserve mechanics lien rights. But even when not required, they provide invaluable transparency and communication.

Procurement log: A spreadsheet that tracks how long it will take for certain materials to be delivered on-site, especially those with long lead times. It tracks when the submittals for these materials need to be approved so that they can be ordered for fabrication and delivery. Some examples of items that may be on a procurement log are structural steel, HVAC equipment, lighting fixtures, and custom cabinetry.

Project schedule: The contract timeline for the duration of the project, usually in Gantt chart format showing relationships and the critical path (what items are driving the overall schedule). It is generally composed of long duration tasks, sorted by scope and location, as opposed to the 3 week look ahead (which is very detailed and short term).

Punch list: A list of all items that need to be fixed before the building or project can be turned over to the client. Punch list items are also known as snags or deficiencies, and include things like paint scratches, damaged siding, cleanup, etc. This process comes at the end of the project after a preliminary walkthrough of the jobsite. The final punch list is usually tied to a cost withheld from the contractor until it is completed and verified.

QA/QC: This stands for "quality assurance/quality control" which is the formalized process of confirming proper installation methods and materials on-site.

RFI This stands for "request for information" which is a formal question to the design team, client, or general contractor that will likely affect the contract scope, drawings, and/or specifications. The response to an RFI acts as a contract change and could result in a change order.

Rough-in: The initial stage of the wall framing, HVAC, electrical, and plumbing installation. This includes all of the components that won’t be seen after the completion of the project. All trade rough-ins must generally be inspected prior to insulation and application of finishes.

Schedule of values: The breakdown of a contract amount into sub-items and sub-costs for identifiable construction elements. This is usually used as the basis for submitting and reviewing progress payment.

Sensor: A device or instrument designed to detect and measure a variable.

Shoring: Temporary structural support for underground excavation to prevent soil movement or collapse. Shoring is used when you can no longer excavate to your maximum allowable slope.

Shotcrete: Concrete that is shot onto a reinforced surface, usually wire mesh, by way of air pressure and hose. Shotcrete is a typically installed on soil nail walls.

Specifications: The instruction manual that is paired with the contract drawings. It includes information such as installation procedures, product brand requirements, and testing requirements, to name a few. It is separated out by CSI (Construction Specification Institute) divisions, generally starting with 01 00 00 through 33 00 00.

Strut: A structural member, usually inclined and shorter in length, used to resist axial force.

Submittal: A document that is prepared by the installing contractor that indicates the products and locations that will be procured and installed. The document will need to be approved by the architect (and other applicable design team members), as well as the general contractor and client. An example of a submittal would be a cut sheet of the sink that will be installed in the bathrooms.

Substantial completion: A milestone in construction projects defined as the stage when work is sufficiently completed in accordance with the contract documents. This indicates that the owner can now utilize the building or facility for its intended purpose. Only minor works, such as punch list items, will ordinarily remain after reaching substantial completion.

Take off: An estimation of the quantity of material required to complete a certain scope of work.

Toothing: When alternating bricks are left projecting from walls in order to bond with future work.

Tremie concrete: Concrete that is designed to be poured underwater through a gravity feed system. This method is often used to create underwater foundations as well as seal cofferdams and caissons.

Variable-frequency drive (VFD): An electronic device that varies its output frequency to vary the rotating speed of a motor given a fixed input frequency. They are used with fans or pumps to vary the flow in the system as a function of a maintained pressure.