Construction terms, plainly defined
Clear definitions of the construction, estimating, and building-code terms contractors and homeowners run into — each one short, accurate, and linked to where it matters.
AFCI (arc-fault circuit interrupter)
An arc-fault circuit interrupter (AFCI) is a protective device that detects dangerous electrical arcing and shuts off the circuit to prevent fires.
GFCI (ground-fault circuit interrupter)
A ground-fault circuit interrupter (GFCI) is a device that cuts power within milliseconds when it detects current leaking to ground, protecting people from electric shock.
Egress / EERO (emergency escape and rescue opening)
An emergency escape and rescue opening (EERO) is a window or door large enough to escape through and for a firefighter to enter — required in every sleeping room.
AHJ (authority having jurisdiction)
The authority having jurisdiction (AHJ) is the local agency or official — usually the building department — that adopts, interprets, and enforces the code where you build.
Takeoff (quantity takeoff)
A takeoff is the process of measuring and counting the materials and quantities needed for a project directly from the drawings — the basis of an estimate.
Overhead and profit (O&P)
Overhead and profit (O&P) is the markup added to the direct cost of a job to cover a contractor's business costs (overhead) and earnings (profit).
Basis of estimate (BOE)
A basis of estimate (BOE) is the documented set of assumptions, inclusions, exclusions, and data sources behind an estimate — the 'show your work' for a number.
AACE estimate class
AACE estimate classes (Class 5 to Class 1) describe how mature and accurate an estimate is, based on how complete the project's design is.
RFI (request for information)
A request for information (RFI) is a formal question from the contractor to the design team to clarify or resolve something unclear in the drawings or specifications.
Submittal
A submittal is the documentation a contractor provides — product data, shop drawings, samples — for the design team to review against the specifications before installation.
Change order
A change order is a written, signed agreement that modifies the contract's scope, price, or schedule after work has begun.
Punch list
A punch list is the list of remaining or deficient items a contractor must complete or correct before a project is considered finished.
CPM schedule (critical path method)
A critical path method (CPM) schedule is a project timeline that maps task dependencies to compute the longest chain of work — the 'critical path' that drives the finish date.
Earned value management (EVM)
Earned value management (EVM) is a method that combines scope, schedule, and cost to measure whether a project is ahead or behind and over or under budget — with objective indices.
Lien waiver
A lien waiver is a signed document in which a contractor, subcontractor, or supplier gives up their right to file a mechanic's lien for payment they have received.
Pay application (pay app / draw)
A pay application (or 'draw') is a contractor's formal request for a progress payment, showing the work completed to date against the schedule of values.
R-value
R-value measures how well insulation resists heat flow — the higher the R-value, the better the insulating performance.
Load-bearing wall
A load-bearing wall is a wall that carries structural weight from above — floors, the roof, or other walls — down to the foundation.
Setback (zoning)
A setback is the minimum distance a building must be kept from property lines, streets, or other features, set by local zoning rules.
Certificate of occupancy (CO)
A certificate of occupancy (CO) is the document a building department issues confirming a structure complies with code and is safe to occupy for its intended use.