Construction Glossary

A chemical additive blended into concrete to modify properties such as set time, workability, air content, or durability.

The intentional introduction of microscopic air bubbles into concrete to improve freeze-thaw resistance and workability.

A bolt cast into concrete that secures the wood sill plate or other framing members to the foundation.

Revised drawings that record the actual constructed locations of all elements as they were built, including deviations from the original design.

Water that rises to the surface of freshly placed concrete as heavier aggregates and cement particles settle downward.

The layer of compacted granular material directly below a paved surface, providing strength and load distribution to the pavement above.

The maximum load per unit area that a soil can support without shear failure or excessive settlement.

A wall that supports the weight of the structure above it, transferring loads from roof and upper floors down to the foundation.

Short pieces of lumber installed between studs, joists, or rafters to provide structural support, fire stopping, or a nailing surface for fixtures.

A permanent reference point of known elevation used by surveyors and engineers to establish vertical control on a project.

A surety bond that protects the project owner if a contractor fails to perform or pay subcontractors and suppliers.

The maximum load per unit area that concrete can withstand before failure, measured in psi at 28 days after placement.

Maintaining adequate moisture and temperature in fresh concrete to ensure complete hydration and proper strength gain over time.

A plane of weakness in concrete that forms when fresh concrete is placed against concrete that has already set, preventing full bonding between the layers.

The thickness of concrete between the outer surface and the nearest reinforcing bar, providing protection from corrosion and fire.

A planned, tooled or sawed groove in a concrete slab that creates a weak point so that shrinkage cracking occurs in a straight, controlled line.

The earthwork process of excavating (cutting) high areas and using that material to build up (fill) low areas to achieve a desired grade.

The mechanical process of densifying soil by reducing air voids, using rollers, plate compactors, or jumping jacks to achieve specified density.

Short studs installed above a header or below a sill to maintain the standard stud spacing and provide nailing for sheathing and interior finishes.

A surveyed point of known horizontal and/or vertical position used as a reference for layout and measurement throughout the project.

A list of stake locations with corresponding cut or fill amounts, used by equipment operators to bring earthwork to the specified grade.

A tube or pipe used to protect and route electrical wiring through walls, ceilings, and underground runs.

A written agreement between the owner and contractor that modifies the contract scope, price, or schedule after the original contract is executed.

The final phase of a project including punch list completion, inspections, certificate of occupancy, O&M manual submission, and final payment.

A systematic process of testing and verifying that building systems are installed correctly and operate per design intent before occupancy.

The process of removing groundwater from an excavation to keep it dry enough for safe working conditions and proper construction.

A metal flashing installed along roof edges (eaves and rakes) that directs water away from the fascia and into the gutter.

The plumbing subsystem that removes wastewater from fixtures and vents sewer gases safely to the atmosphere above the roofline.

The network of metal or flexible conduit used to distribute conditioned air from HVAC equipment throughout a building.

A written record kept by the superintendent documenting work performed, crew counts, deliveries, weather, visitors, and issues each day.

A full separation between two concrete sections, filled with compressible material, that allows independent movement due to temperature changes and settlement.

Measures taken to prevent soil disturbance from being transported off-site by water or wind during and after construction.

The lower edge of a roof that overhangs the exterior wall, providing protection from rain and directing water away from the foundation.

The vertical height of a point above a reference datum, typically mean sea level, expressed in feet.

A legal right granted to a person or entity to use another's land for a specific purpose, such as utility access, drainage, or pedestrian passage.

Temporary molds made of wood, steel, or engineered panels used to shape and support concrete until it gains sufficient strength to stand alone.

A horizontal structural member that spans between supports to carry floor loads, typically spaced 12, 16, or 24 inches on center.

Solid wood, drywall, or other approved material installed in concealed wall and floor cavities to slow the spread of fire through building framing.

Sheet metal (typically aluminum, galvanized steel, or copper) installed at roof transitions, penetrations, and joints to prevent water from entering the building.

The vertical board at the end of the rafters along the eave edge that supports the gutter and provides a finished appearance to the roof edge.

A written directive from the owner or architect instructing the contractor to perform work immediately, before a formal change order is issued.

A permeable synthetic fabric used in geotechnical applications to separate, filter, reinforce, or drain soil layers.

The slope or level of the ground surface, or the specified elevation to which earthwork or concrete must be brought during construction.

The contractual section and associated job-site costs covering administrative, legal, and procedural requirements for the project.

A horizontal framing member placed over a door or window opening to carry the load from above and transfer it to the trimmer studs on either side.

Heating, Ventilation, and Air Conditioning — the systems that control a building's thermal comfort, air quality, and humidity.

A self-adhering waterproof membrane applied at roof eaves, valleys, and other vulnerable areas to prevent water infiltration from ice dams and wind-driven rain.

A contractual obligation where one party agrees to protect another from legal claims, losses, or damages arising from the project.

The overlap length required between two rebar pieces to transfer load from one bar to the next through the surrounding concrete.

An engineering calculation that determines the heating, cooling, or electrical demand a building system must handle.

A pre-agreed daily penalty specified in the contract that the contractor pays the owner for each calendar day the project is completed past the contract completion date.

A document from the manufacturer certifying the chemical composition and mechanical properties of a specific heat or batch of steel or other material.

A full-scale sample of a material, assembly, or system built on-site for owner and architect review before full installation proceeds.

The techniques, sequence, and procedures a contractor uses to accomplish the work; generally the contractor's responsibility, not the designer's.

A written document issued by the owner to the contractor authorizing and directing them to begin work, establishing the contract start date.

A legal document filed by the property owner at project start that establishes the timeline and identifies parties for mechanics lien purposes.

A 10-hour OSHA-authorized training course covering construction safety fundamentals, hazard recognition, and workers' rights.

A laboratory test that determines the optimum moisture content and maximum dry density for a specific soil, used as the benchmark for field compaction.

The legally defined boundary that separates one parcel of land from adjacent parcels or public rights-of-way.

A test that applies air or water pressure to a piping system to verify it holds without leaks before walls are closed.

A surety instrument that guarantees the contractor will complete the work per contract terms; the surety steps in if they default.

A surety bond that guarantees the contractor will pay all subcontractors, laborers, and material suppliers on the project.

The legally mandated minimum wage rate for specific trades on publicly funded projects, set by federal Davis-Bacon Act or state law.

Personal Protective Equipment — gear worn to minimize exposure to hazards, including hard hats, safety glasses, gloves, high-visibility vests, and steel-toed boots.

A list of items identified at or near substantial completion that must be corrected, completed, or replaced before final payment is released.

Steel reinforcing bars embedded in concrete to provide tensile strength, since concrete is strong in compression but weak in tension.

The outermost joist running along the perimeter of a floor frame, perpendicular to the floor joists, that caps the joist ends and provides lateral stability.

A prefabricated engineered structural assembly of lumber and metal connector plates that forms the roof structure, spanning from exterior wall to exterior wall.

A sloped framing member that forms the structural element of a pitched roof, running from the ridge board or beam down to the top plate of the exterior wall.

The horizontal board at the peak of a roof against which the tops of opposing rafters are nailed, providing a nailing surface but not serving as a structural beam.

The slope of a roof expressed as the number of inches of vertical rise for every 12 inches of horizontal run — for example, 4:12 or 8:12.

A unit of roofing measurement equal to 100 square feet of roof surface area, used to quantify materials like shingles, underlayment, and decking.

The structural sheathing (typically OSB or plywood) applied over roof rafters or trusses that provides the surface for roofing materials.

A continuous waterproof sheet applied to low-slope or flat roofs, including TPO, EPDM, and modified bitumen systems.

A strip of land dedicated or reserved for a specific use such as a road, utility line, or public trail, within which property owners have limited rights.

The initial phase of MEP installation where pipes, conduit, and ductwork are run through walls and floors before the finishes are applied.

A percentage of each progress payment withheld by the owner until project completion to ensure the contractor finishes the work and corrects deficiencies.

Request for Information — a formal written question from the contractor to the architect or engineer seeking clarification on the contract documents.

A measure of the consistency and workability of fresh concrete, determined by filling a cone mold, lifting it, and measuring how far the concrete settles.

The native or prepared soil layer at the bottom of a pavement or foundation system that provides the ultimate support for loads above.

A layer of granular material (typically crushed stone or gravel) placed between the subgrade and the base course or pavement to distribute loads and improve drainage.

The increase in volume that occurs when soil or rock is excavated from its natural state, due to the introduction of air voids.

The reduction in volume when excavated soil is recompacted as fill, compared to its bank (in-place) volume.

A structural wall designed to resist lateral forces from wind and seismic loads by acting as a rigid vertical diaphragm.

A vertical framing member in a wall, typically 2x4 or 2x6 lumber spaced 16 or 24 inches on center, that supports loads and provides nailing surface for sheathing and drywall.

The underside of the roof overhang (eave), typically finished with vented panels to allow air into the attic and prevent moisture buildup.

The process of establishing the physical location of a structure or feature in the field by placing stakes based on construction plans and coordinates.

The minimum distance a structure must be located from property lines, roads, or other features as required by local zoning regulations.

The point where the utility's power lines connect to the building's electrical system, including the service conductors, meter, and main disconnect.

A detailed written description of exactly what work is included and excluded in a contract or subcontract.

A specialty trade contractor hired by the GC to perform a specific scope of work such as electrical, plumbing, or steel erection.

The on-site manager responsible for daily construction operations, crew coordination, schedule, safety, and quality control.

A standardized document providing hazard, handling, storage, and emergency response information for chemical products used on job sites.

The stage of construction when the work is sufficiently complete that the owner can occupy and use the facility for its intended purpose.

A document, sample, or shop drawing submitted by the contractor for architect or engineer review to verify that proposed materials and methods conform to the contract documents.

A detailed drawing prepared by a subcontractor or fabricator showing how specific elements will be manufactured and installed, submitted for design team review.

Horizontal framing members at the top and bottom of a stud wall. The top plate is typically doubled to tie corners and intersections together.

A shortened stud that runs from the bottom plate to the underside of a header, supporting the header on each side of a door or window opening.

A series of connected survey lines used to establish horizontal control across a project site, with each line's length and direction measured.

A water-resistant layer installed directly over the roof decking and under the finish roofing material to provide secondary protection against water infiltration.

A sheet of polyethylene film placed under a concrete slab-on-grade to block ground moisture from migrating up through the slab.

The internal angle formed where two roof slopes meet, which concentrates water runoff and requires special waterproofing treatment.

The ratio of water weight to cement weight in a concrete mix. Lower ratios produce stronger, more durable concrete.

A contractual promise that work will be free from defects in materials and workmanship for a specified period after substantial completion.