Definition of Construction Industry Terms

People involved in the construction industry frequently communicate in a language that may be foreign to the uninitiated. Often the use of a single word or phrase can sum up an operation, identify a piece of equipment, or describe the function of a person involved in the industry.

Familiarization with the following "jargon" should contribute to better communications and interactions with construction related risks. While most of the terms apply throughout the industry, some may be specific to certain geographical areas. Also, trade names are listed as they are often used as field language.


ABC: Aggregate base course used in highway surfacing to furnish a compact, stable, and even surface.

A.B.C. process: A method of deodorizing and precipitating sludge by the addition of alum, charcoal, clay, or some other material, to the raw sewage.

A.M.F.: The abbreviation of a parting remark by construction superintendents as they “button up” a project and leave it for the last time.

ABS plastic: Black plastic pipe used in buildings for plumbing drains.

Abate: (1) To cutaway, as in stonework, or to beat down, as in metalwork, so as to leave parts in relief. (2) A diminuition or reduction by amount of degree of discharges, such as pollutants into receiving waters.

Abatement: In carpentry, the wasting of timber when shaping to a size; hence a decrease in its strength.

Abatvent: A contrivance to break the force of, or prevent the entrance of, wind, as in a louver or chimney cowl.

Abraded: Pertaining to a surface that has been worn by surface rubbing.

Abrasion: The wearing of a surface through rubbing with another surface.

Abutment: The end of a culvert or bridge that protrudes above the ground. The abutment is usually made of concrete.

Accelerator: (1) An admixture, such as a hardener or catalyst, which, when added to concrete, mortar, plaster, or grout, increases the rate of hydration of the hydraulic cement, shortens the time of set, or increases the rate of hardening or strength development. (2) A pump for circulating water through a heating system.

Accessed: To gain access to an area via a prescribed path (e.g., the tub drain is accessed through an opening in the closet).

Accident: In insurance terminology, a sudden, unexpected event identifiable as to time and place (also see occurrence).

Accolade: A decorative use of a molding over a door or window, in which two ogee curves meet centrally at the top.

Accumulate: To acquire quantities of something.

Acoustical: A sound related term that is often used as follows: the ceiling has acoustical tile, which is used to reduce or deaden sound in the room.

Acoustic tile: Tile-shaped blocks of sound-absorbent material used for ceilings or as wall facing.

Acrylic terpolymer: An acrylic-based terapolymer caulk, often used on roof surface applications.

Adiabatic: A condition in which heat neither enters nor leaves a system.

Admixture: A material added to cement or the concrete mix to increase workability, strength, or imperviousness; to lower freezing point; to prevent scaling; or otherwise to affect the concrete. Accelerators, plasticizers, and air-entraining agents are admixtures.

Advisable: A recommended or suggested action or means of performing a task.

Aerate: To infuse air into a liquid, such as air into water, at a lavatory faucet.

Aerator: A device used to infuse air into a liquid, such as the aerator on the spigot of a faucet that is used to inject air into a water stream.

Aesthetics: The appearance of an item or condition that that tends to stimulate or enliven the senses.

Air entrainment: When air is mixed with water in a hot tub or whirlpool tub recirculation system, or when water rushes past an orifice and draws in air to be mixed with the water flow.

Algaecide: A chemical that, when added to a solution, prevents the growth of fungus and algae.

Allen wrench: A six-sided rod of various diameters that is used for removing or installing screws or bolts having a female six-sided indention into which the wrench will fit.

American Standard Plumbing: The trade name of a plumbing supply manufacturer that also makes air conditioners, furnaces, and fans.

Ampacity: A conductor's current-carrying limit.

Amps (slang): A measure of electrical current used to define the energy supplied to an electrical appliance.

Anaerobic: A term generally used to define bacteria in a septic system that do not require oxygen to live and perform.

Anchor blocks: Blocks of wood built into masonry walls, to which partitions and fixtures may be secured.

Andirons: The supports for logs in a wood burning fireplace, the exposed ends of which are usually decorative.

Anneal: To reduce the brittleness and increase the ductility of metal by heating to a certain temperature, then cooling slowly in air or oil.

Annular ring shank (ring shank nail): A term used to define a nail that has annular rings around the shank that hold the nail in place when driven into wood.

Anode (in a water heater): An anode is a sacrificial metal rod placed in a water heater that will selectively corrode due to dissimilar metal electrolytic corrosion.

Arrisways: In building, a term used when referring to tiles or slates that are laid diagonally.

Askew: A line or plank installed so that it is not aligned with other objects of similar nature; the line or plank is said to be askew.

ASTM: Abbreviation for ASTM International, Inc., formerly the American Society for Testing and Materials. The society establishes the acceptable range of product usefulness based on tests.

Awl: A sharp, pointed tool similar to an ice pick that is usually used for scribing a metal surface or punching holes.


BM (bench mark): An established elevation for comparing with other elevations.

Babbit: A soft, antifriction metal composed of tin, antimony and cooper, in varying proportions.

Back coating: An asphalt coating applied to the back side of shingles or roll roofing.

Backsplash: The back wall of a tub, sink, or lavatory basin that is usually made of a surface that is not adversely effected by being wet.

Balcony: A porch, usually with a safety hand rail at the perimeter, that is above the first floor of a building.

Ballast: In electrical terms, the transformer in a florescent light that maintains the proper induction and voltage for the light bulb to glow.

Ball cock: An automatic arrangement in flushing tanks or other cisterns whereby a floating copper or plastic ball opens the cock when the cistern is empty and closes it as it floats up while the cistern fills.

Baluster: The vertical column in a hand rail that supports the hand rail and prevents passing under the rail.

Banjo (slang): A short-handled shovel.

Banister: The rail at the top of a hand rail to which a person holds when using stairs.

Battboard: The planks used on siding to cover joints between sections of siding or joints between different types of sidings.

Bays formed by floor joists: The space between floor joists and the underside of a floor.

Belled bottom piers: Subterranean piers used to support the foundation of a structure. Belled bottom piers are constructed by drilling a shaft, then using a belling tool to form a conical shape at the bottom of the pier in order to distribute the load of the pier over an area larger than just the shaft.

Bending moment in floor joist: The force or load applied that tends to bend floor joists. The bending moment cannot induce stress in the floor joists that exceeds the strength of the floor joists or they will fail.

Berms: Ridges in soil that are used for decoration, or dams to control water flow.

Beryllium copper: A copper alloy that is springy, usually used for weather stripping of doors.

Bidet: A plumbing fixture containing a basin that is generally used for personal hygiene.

Bi-fold: This term is used in reference to a segmented door that folds at the center.

Binding rafter: A horizontal structural member (beam), which runs along the underside mid-span of the roof rafters. Also see purlin.

Bi-parting doors: Doors used on a freight elevator to give clear passage as wide as the width of the car. The doors part vertically in the center, with the top section counterbalanced by the bottom one.

Bird's mouth splice: A splice in a piece of lumber made by taper sharpening one end of a plank to be spliced and notching the other end of a plank to be spliced. The tapered end is inserted into the notched end and the joint is secured with nails or screws.

Bitumen: An asphalt-based material that is used to bond glass matts together to form felt paper or a built-up roof surface.

Blow off: In sewage work, a pipe outlet for discharging sediment or water, or for emptying a low sewer.

B-nut: A nut used to secure flared tubing to a special fitting.

Board foot: A unit of measure represented by a piece of lumber that is one foot long, one foot wide, and one inch thick (12" x 12" x 1"), or 144 in3.

Boar's nest (slang): A bunkhouse on a construction job.

Borers (insects): Insects that bore into trees and cause damage that may cause the tree to be unusable for lumber.

Brad: A flat nail, the head of which projects on one side only, so that in effect the wood closes behind the nail once it is hammered in.

Braze: To solder with brass or other hard alloys.

Breast: (1) A projecting portion of a wall, usually in connection with a chimney. (2) The moldboard of the plow of bulldozer. (3) A riser of a stair. (4) The wall under the sill of window down to the floor level.

Briar roof material: The trade name of a modified bitumen roof originally manufactured in Germany.

Brick guard: The trade name of a clear sealant used to seal bricks and prevent water penetration.

Broomed finish: The finish applied to a concrete surface that is obtained by brushing the concrete surface with a broom prior to the concrete curing.

Building Officials and Code Administrators International (BOCA): Publishes the National Building codes series.

Build-up: The term used when something accumulates to an undesirable or excessive amount. An example is the accumulation of ice on a roadway.

Bus bar: Copper or aluminum bars in a circuit breaker box used to transmit or terminate AC or DC power.

Buster: A machine for cutting off the heads of rivets; also the edged tool which does the cutting.

Butt plate: The end plate of a structural member, usually used to rest against a like plate of another member.


"C" section: A member formed from steel sheet in the shape of a block "C," that may be used either singly or back to back.

Cabana: A small building usually next to a swimming pool.

Calf's-tongue molding: A molding having a series of pointed, tongue-like members in line in relief against a plane or curved surface; sometimes radiating from a common center.

Caliche soil: A soil consisting of a white clay and aggregate used as paving for streets and parking surfaces.

Calrod: An electrical heating rod that becomes hot when electrical current is allowed to flow through its heating element.

Campo: An Italian measure of land, roughly an acre.

Cantilevered floor joists: Floor joists that extend beyond an end support so that the ends are considered similar to a cantilevered beam.

Capacitor (used in an air conditioner): A electrical capacitive device that is used for running and/or starting a compressor motor.

Capillary (used in an air conditioner): A capillary tube that meters refrigerant to an evaporator coil to obtain boiling refrigerant in the evaporator coil.

Capping (roots of trees): The term used when the roots of a tree are cut and a barrier is placed between the tree and a foundation.

Carborundum: An abrasive material that, if used in saw blade construction, will cut steel, masonry, and other very tough materials.

Carcass: The loadbearing part of a structure without windows, doors, plaster or finishes; the frame of a house; the unfinished framework, or skeleton, of a building or ship.

Carcinogen: Any substance or agent that promotes cancer.

Catchpan: In air conditioning, it is a pan placed below a device, such as an evaporator coil, to catch condensate that drips off the evaporator coil.

Cellulose insulation: An insulation used in buildings that is made from recycled newspaper and treated with fire retardants and insect protection.

Celotex sheathing: A brand name sheathing that is used as an underlayment for various sidings.

Cement-asbestos roof: A roofing membrane composed of asbestos fibers and cement. The same material has been used for siding and water pipe construction.

Cementious: A material that is similar to concrete or plaster which has a cement-like characteristic.

Central air conditioning: A system which uses ducts to distribute cooling and/or dehumidified air to more than one room or uses pipes to distribute chilled water to heat exchangers in more than one room.

Chlorine: An elemental gas that is a strong oxidizer; a chemical that is used for biological purification of water.

Circuitous: A term used to indicate that a devious path was used to obtain a certain result.

Clorox: A trade name for a chlorine-based chemical that is used as a bleach and cleaning agent.

Cobbling (fireplace chimneys): The term used when the fireplace flue pipe and enclosure is offset as it passes through the attic.

Coliform (microscopic bacteria): Organisms found in polluted water that will make people ill if ingested.

Collapse: Referring to the failure of a structure or machine to support an intended load.

Compaction: The state of a material, such as soil to be compacted.

Compotite (shower pan material): An asphalt and plastic sheet material that is folded and shaped into a shower pan for shower-bathing enclosures. The material is no longer used for shower pans.

Compressor: In air conditioning, it is the equipment that increases the pressure of the refrigerant.

Concave (a surface): A surface area with the center portion of the area being lower than the outer edges of the area.

Condensate: Water that collects as a result of cooling below its dew point. This occurs at the evaporator coil of an air-conditioning system, and must be disposed of in a sanitary manner. This may also occur between the panes of double paned window, and at cold pipes, ducts, or other cool surfaces.

Contactors: The term is used to indicate an electrical relay that is used to provide power to a large motor, such as the compressor of an air conditioning system.

Conventional reinforced concrete slab on grade foundation: A term used to define the method of reinforcing a concrete slab foundation that rests on the soil. “Conventional” means through the use of steel reinforcing bars.

Convex: A surface area with the center portion of the area being higher than the outer edges of the area.

Convolutes: A term used to define a hose that is constructed by supporting a membrane on wound wire or similar material to form a hose or duct that will bend when pressurized.

Corev siding: A trade name for an EIFS siding that is sometimes used in the place of stucco, i.e. an imitation stucco siding.

Corner batt: The term used to describe the three corner points from which a concrete form is started.

Corner bead: A strip of formed galvanized iron, sometimes combined with a strip of metal lath, placed on corners before plastering to reinforce them. Also, a strip of wood finish three-quarters-round or angular placed over a plastered corner for protection.

Council of American Building Officials (CABO): The umbrella organization for the three nationally-recognized model code organizations in the United States - the Building Officials and Code Administrators (BOCA), the International Conference of Building Officials (ICBO), and the Southern Building Code Congress International (SBCCI).

Counterflashing: A part of a flashing system used where a roof surface comes in contact with a brick veneer wall. The counter flashing is attached to the brick veneer and a lip hangs down over an upturned portion of an "L" flashing at the edge of the roof.

Crawlspace: Area where crawling space is provided to gain access to equipment or structure. This may be the area between the underside of a structure and the soil in pier and beam type foundations, or and access way through an attic.

Creosoted: A term used to define lumber that has been treated with creosote at high temperatures and pressures. The creosote reduces the rate of decay that will usually occur in wood.

Cripple stud: A shortened stud, usually of 2x4 inch, wood that us used to support the header beams over doors and/or windows.

Crush box (of foundation grade beam): A cardboard or foam box used below foundation grade beams to create a void between the soil and the concrete grade beams. This has not proven to be effective so its use is not recommended.

Cross connection: Any physical connection or arrangement between potable water and any possible source of contamination.

Culling: The sorting of masonry units for size, color, or quality.


Dado: A decorative molding on the lower portion of an interior wall.

Dead band adjustment: An adjustment to control the point where an instrument will turn a device on and a second point where it will turn the same device off.

Deadbolt: A term used to define a lock that can only be engaged and disengaged with a device (i.e., knob or key). The bolt is square at the end and will not allow engagement by merely closing a door.

Deadman: (1) An anchor for a guy line, usually a beam, block, or other heavy item buried in the ground, to which a line is attached. (2) A stake.

Decant: To pour off a liquid without disturbing a sediment or precipitate.

Delta T: A term used to indicate a difference in temperature between two points, i.e. the difference in air temperature between the inlet and outlet sides of an air conditioning system evaporator coil.

Denney board: A term used for a sheathing material of about 1/8 inch that is usually silver in color to reflect radiant heat; the material can be structural, as well as moisture and heat resistant. A trade name is Thermocote.

De-Ox (anti-oxidization comp): A material used to coat wiring and connectors to prevent corrosion and oxidation due to heat accumulation.

Desiccant (drying agent): A material that, when placed in a sealed container, attracts and holds moisture to prevent moisture damage to items that is stored with it. A desiccant in the refrigeration loop of an air conditioning system prevents free moisture from adversely affecting the operation of the system.

Detent latch mechanism: A spring-loaded latch mechanism that can be used to hold a door in a closed or open position. Usually a spring loaded ball or roller pressed into a depression.

Diatomaceous earth filter: A filter, such as used in a swimming pool water cleaning filter that contains diatomaceous earth through which water is circulated to keep it clear and clean.

Differentially: A term used to indicate difference in vertical displacement of different points on a concrete slab.

Dogtrot: A covered passage joining two parts of a house, such as a covered porch between house and a wing; a breezeway.

Dolphin: A cluster of piles driven in water for mooring purposes or for protection against floating objects.

Double jack (slang): A sledge hammer; usually six or eight pounds in weight.

Double-pole switch: A switch to connect or break two sides of an electric circuit.

Dowels (rods): A round rod of wood that varies in diameter with its intended use.

Downspouts: The pipes extending from the gutter on a roof to the ground.

Dryvit: A trade name for an imitation stucco siding that has been known by the term EIFSs (Exterior Insulation Finishing Systems).

Ductboard: A fiberglass-based board having an aluminum foil on one side and exposed fiberglass on the other. The material is used to fabricate cheap air ducts for air conditioning systems.


Earth pin (slang): A rod made of steel, wood, or other strong substance that is driven into the ground for use as an anchor for anything that needs to be tied down.

Eaves: The part of a roof that projects over the side wall; a margin or lower part of a roof hanging over the wall.

Efflorescence: A powdery, mineral deposit on the surface of a floor or wall, usually caused by moisture evaporation.

Effluent liquid waste: The material discharged from a processing system or plant, such as the material discharged from a sewage treatment plant.

Egress: A term used to describe the exit from a room or building.

Elastomeric coat on stucco: A film, which is usually plastic in nature, that will stretch and is composed of an elastomer that is usually painted on a surface.

Elasticity: That property of a material by virtue of which it tends to recover its original size and shape after deformation or compaction.

Elastic limit: The limit of stress of a material beyond which the strain is not wholly recoverable. In most materials, it is also the limit of proportionality.

Elephant trunk (slang): (1) An articulated tube or chute used in concrete placement, especially to place concrete under water. (2) A steel flex tube with a ball on the input end that guides the wire into the conduit smoothly.

Electrolytic: A term used for an electrical component having a paste or fluid electrolyte. An example is an electrolytic capacitor.

Emanating: A term used to indicate the source of a smell, a sound, or a discharge of materials or other type substance.

Emissivity: A term used to define the capability of a surface to reflect or absorb heat.

EPDM (Ethylene Propylene Diene Monomer) roof: EPDM is an elastomeric compound that is manufactured from ethylene, propylene, and a small amount of diene monomer. These ingredients are synthesized to produce a membrane that is used as a roofing material. A trade name is Neoprene.

Epoxy: Epoxy is a two-part, resin-based material that is used with a fiberglass matt to make repairs in plumbing systems.

Equilibrium: The term is used when there is a balance between two or more conditions. An example is when the pressure is equal on two sides of a membrane.

Eroded: Something or a surface that has been worn away, usually by water or air flow. An example is: the brick mortar has been eroded away by water flow.

Escutcheons: The cover plate around a faucet valve stem where it protrudes through a wall or sink.

Extruded: A term used for the hot forming of objects where a melted, or near melted material, is forced through a die to form a piece with a consistent cross section.


Fairing strips: The decorative strips of wood used in windows to make a smooth transition from the glass panes to the frames that hold the panes.

Fairings: Covers used to smooth the transition between one surface and another.

Fascia: The term used for the vertical plank or area along the edge of a roof.

Ferrule: A metal sleeve or tube that has various uses. A ferrule can be used to divert water from a fireplace flue chase where the flue passes through the cap. A bushing used to secure a pipe joint.

Fibrous: A term used to describe a material that consists of fibers. An example is fibrous aluminum paint used to cover a felt built-up type of roof.

Fireplace mantel: The horizontal shelf in the face of a fireplace that is placed across the top of the firebox opening.

Flake board: A plywood-like panel composed of flakes of wood compressed and bonded together with some type of cement. The panels are usually 4 ft by 8 ft (1.2 m x 2.4 m).

Flashings: Sheet metal used to weatherproof the joints on a roof, at the tops of doors and windows, and at other horizontal joints in vertical surfaces in order to prevent water penetration.

Flexure: A term often used to define the bending of a beam under load.

Flitch plate: The term typically refers to the stiffening member in a beam that is comprised of several pieces secured together with fasteners in order to make a stronger composite beam. The flitch plate is usually constructed of plywood or steel.

Flue: The vent for an area where a combustible material is burned. An example is the vent of a fireplace that is used to dispose of combustion products.

Formaldehyde: A chemical that is used in many finishes and insulations and which is considered a carcinogen.

Fractional H. P. pump: A pump that is driven by a small motor having a power rating under 1 hp (0.7 kW), isually less than 1/6 hp (0.12 kW).

French doors: Glass-paned double doors that hinge from opposite sides of an opening.

Frieze molding: A decorative horizontal band, usually of wood, installed at or near the top of a wall. The band is intended to hide the joint between the ceiling and wall.

Furr downs: The lowered portion of a ceiling above a cabinet or closet. The furr down is intended to improve the appearance of a cabinet by closing the opening between the ceiling and the top of a cabinet.


GAF rubberroid roof: A single-ply roof membrane, manufactured by GAF, that is made with neoprene rubber. It is usually held in place with fasteners at the edges and stones spread on the surface.

Galvalum: A steel panel coated with a zinc and aluminum film to prevent or reduce corrosion.

Galvite paint: A paint-like liquid that can be applied to steel surfaces to inhibit corrosion.

Gambrel ceiling: A ceiling that has a flat central surface with sloped surfaces between the walls and the horizontal portion of the ceiling.

Gauge: A term used to define the dimension of something as related to a standard. An example is a 12-gauge electrical wire.

Gell-coat: A petroleum-based finish coat used on fiberglass materials for improved appearance.

GFCI (Ground Fault Circuit Interrupter): An electrical device, either at the circuit breaker panel box or at individual outlets, which opens the circuit it controls if it detects current flow through the ground leg of the circuit. They are normally used in wet, moist, or damp areas where a shock hazard exists.

Graffito: A plaster surface decorated by scoring a pattern on it while soft thus exposing a lower coat of a different color, often black or dark red.

Grommets: A device used to line an opening so that the edges are protected against something that may pass through the opening. An example is a grommet placed in the cutout of the cabinet of an appliance through which electrical wires are passed.

Gunite: A cement-concrete material that is sprayed on a surface or into a form. Swimming pools are often made with gunite.

Gypsum board: A flat panel made of compressed gypsum that is covered with paper on each side and which is used as a wall-covering material.


HACR circuit breaker (used with A/C): A resistance-type circuit breaker that has characteristics usable with air conditioning system compressor circuits.

Hand-held spirit level: A flat, bar-like tool that has a curved, alcohol-filled tube mounted in it so that a bubble left in the tube centers between two lines when the bar is placed on a level surface.

Hermetically sealed: The term is often used to describe a device that has an airtight seal (i.e., sealed form the environment).

Horsing up: In plastering, building up a horsed mold for running a cornice, etc.

Hot wrench(slang): Using a cutting torch to disassemble or loosen lug bolts.

Hydite blocks: A light-weight, cement-concrete block used for partitions within buildings.


Impedance adapter: A device that will match the impedance between two components of an electrical system, such as matching the impedance of a speaker to an amplifier.

Incertum: A kind of masonry wall made of rough stones without horizontal course lines.

Infiltration: The act of something seeping or working its way into an area, such as attic air seeping or leaking into a house, causing loss of energy.

International Conference of Building Officials (ICBO): The organization the publishes the Uniform Building code series.


Jalousie windows: Windows that are constructed of horizontal slats of transparent material, such as glass, that can be opened by tilting the slats from near vertical to horizontal.

Jerry-rigged: The rigging or repair of something that is not done in a professional manner. The lack of quality usually indicates that the repair cannot be expected to perform for a long period of time.

Jib crane: A crane with a portion of its boom hinged near the top so that it does not align with the main portion of the boom.


Kerf: The gap left by a saw blade as it passes through a material.

Kick plate: The vertical component between the floor and underside of a cabinet which is usually set back from the front of the cabinet by several inches.

Kraft paper: A stiff paper, usually brown in color, used to make paper bags, cover a floor during construction, and as an underlayment for certain surfaces, such as metal roofing.


Label stop: An ornamental terminal of a drip mold; a knot or knob.

Lap & gap rough siding: A wood siding that is cut with an apparent gap in surface elevation that overlaps at the edges of the siding planks. The term “rough” applies to the surface finish on the siding.

Lath (metal): The material used to attach stucco or plaster to the framing of a building. The material is usually called expanded metal lath because it is made by cutting slots in metal sheets and pulling it to cause the slots to open.

Lathe (machine): A material-working machine that turns material along an axis so that it can be symmetrically shaped around the axis.

Leach: The term is used to define the action of water passing through a material, such as brick or concrete, and carrying a mineral from the brick or concrete with it.

Lead bend: A term applied to a bent drain pipe, made of lead, that is used to connect a toilet to a plumbing drain system.

Leaded glass windows: Windows that are constructed of various shaped and colored panes of glass that are held together by lead solder.

Liaison: A term used to define a technical relation between two groups.

Lien: A financial document used to indicate a mortgaged property. When a lien exists against a property, the property cannot be transferred to a new owner without the lien holder’s consent.

Lintel: A beam, usually of steel, used to support masonry work above an opening in a masonry wall or fence.

Line of flight: The angle of ascent of a stair.

Lip: (1) The cutting edge of a bucket; applied chiefly to edges including tooth sockets. (2) The banding on a flush door.

Lip joint: In terra cotta, a joint similar to a carpenter's rebate.

Load-bearing: A term applied to a column or wall that supports a load. An example is that a load bearing wall is one that supports the roof or structure above it.

Longitudinal axis: The horizontal axis of an object.

Louvers: The tilted slats installed in an opening, usually a vent opening, such as for attic ventilation or for combustion air ventilation. The louvers are intended to prevent water entry or small animal access to an area.

Lug down: To slow down by increasing load beyond capacity.

Lytag: A lightweight aggregate made of fly ash.


Mandrel: (1) The cylindrical arbor or spindle on which a roll of felt or roofing is wound in the process of manufacture. (2) A piece of wood that is pushed through a pipe to enlarge it or remove distortions (see arbor).

Manlock: A chamber through which men, not materials, pass from one air pressure environment into another. It is used as an access to a shaft, tunnel, or caisson.

Mantle (of a light): The element that is heated to cause illumination, such as the cloth-type element in gas lights often used in yards for area lighting.

Masonry: A term applied to walls or objects made with stone, brick, cement block, or other cement or stone-like materials.

Methyl ethyl keytone (MEK): A cleaning solvent that is not widely used because it is considered a carcinogen.

Mica: A silicate mineral used as either a surfacing or backing material on composition roofing.

Midrail: As defined by the Occupational Safety and Health Administration, a rail approximately midway between the guardrail and platform and secured to the uprights erected along the exposed sides and ends of platforms.

Milled: Having a serrated surface, which is useful in circular metal forms that are to be turned by hand.

Miter: The angle cut across a construction member so that the cut end of the member will fit against the side of another member. An example is the fit of the upper end of a rafter against the ridge beam.

Molding: The term applied to a decorative edge trim that is installed to smooth a joint between two surfaces, such as between walls and ceilings or between walls and floors.

Monolithic: An object that is one piece and not composed of several pieces connected together. An example is a concrete foundation that is cast at one time, as one piece.

Mormon clamp: A term applied to a clamp installed around a cylindrical object to connect two halves together. The clamp usually has a U or V cross section that fits over lips on two different portions of a cylinder and serves to pulls two halves together as the clamp is tightened in place.

Mortise lock: A lock designed to be installed into a mortise extending edgewise into the stile of a door.

Moused: A method of winding with wire for the purpose of securing an object.

Mouse hole (slang): A rotary drill substructure; a socket that holds a single piece of drill pipe ready to be added to the string.

Muckers: Laborers who clean (muck) out tunnels and excavations.

Mullions: The vertical and horizontal strips installed over large panes of glass in windows to make it appear that the window is composed of several separate panes of glass.


New York rod: A leveling rod marked with narrow lines, ruler-fashion.


Oculus: The circular opening occasionally formed at the top of a dome.

Oeil-de-boeuf: A bull's-eye window, circular or oval.

Ohm: A measurement term used to indicate the resistance to current flow through a conductor.

Orangeberg pipe: A black composition material pipe used in the 1950's to conduct sewage from a building to a disposal point.


Paneled or paneling: The term used to define a wall covering where a natural-finish, usually stained, wood panel is applied in a room.

Panic bolt: A door latch operated from the inside by pressure against a horizontal bar running practically across the full width of the door.

Pap: The vertical outlet from an eaves gutter.

Parquet: A term applied to hardwood flooring where the wood flooring is fabricated by small, short, planks assembled together in small 6 to 8 in (15.2 to 20.3 cm) squares.

Particle board: A panel of wood fabricated by cementing saw dust or small particles of wood together with resins.

Particulate: A term used to define the count, or number, of particles found in a specified quantity of a solution.

Phenolic case: A type of plastic case that is usually not flammable. Phenolic cases are usually found in electrical systems.

Plane (planning): A term used in construction to indicate a surface has been smoothed by cutting away some of a rough covering with a blade. Similar to sanding, but the term usually indicates more material is removed than with sanding.

Plenum: A term used to define the air distribution or inlet box of an air distribution system. In air conditioning, a plenum is a box to which air distribution ducts are connected to carry conditioned air to various rooms.

Plies: A term used when a film or surface is constructed by adding one film over another.

Pneumatic: A term used to describe a system that is operated by air pressure.

Polybutylene: A plastic that is formed into pipes and used in water systems. The product remains flexible at relatively low temperatures; however, it does not perform well when exposed to chlorine for extended periods of time.

Polyethylene: A plastic that is used for fabricating pipe, plastic film, and other things of a similar nature.

Polyurethane: A plastic frequently used to create a foam that becomes hard and acts as an insulation and sealer. The plastic usually does not work well when exposed to the direct rays of the sun.

Polyvinyl chloride (PVC): A plastic frequently used for fabrication of water piping, and many other plastic components. The material is widely used in drain pipes and for water distribution pipes outside buildings.

Pookee (slang): Any sticky sealant used in construction industry.

Popout: The breaking away of small portions of a concrete surface due to internal pressure, which leaves a shallow, typically conical, depression.

Porosity: A term used to indicate how porous a material is. A highly porous material is said to have high porosity.

Porte-cochere: A term used for a portion of a building that is used for cover for automobiles. The porte-cochere usually contains rooms that are high enough above a drive to allow an auto be parked below them.

Postern: A door of secondary importance, often beside a large gate.

Post-tensioned cable reinforced concrete slab on grade: A term used to define a concrete slab that is reinforced with steel cables. The cables are spaced several feet apart in the width and length of the slab, at 90 degrees. The cables are stretched after the concrete has cured so that the slab is placed in compression.

Potman: A skilled laborer who prepares and heats solid asphalt for application.

Prerogative: A term used to indicate that someone has the right to act in a certain way even though it may not be a desirable way to act.

Primary members: The main, load-carrying members of a structural system, including the columns, end wall posts, rafters, or other main support members.

Propagate: A term used to indicate something is extending across a domain. An example is that a crack has propagated (spread or extended) across a concrete slab.

Psi: An abbreviation for pounds per square inch.

Purlins: A horizontal structural member, such as a beam, that runs along the underside mid-span of the roof rafters. Purlins distribute the load, provided by vertical supports, uniformly across the roof rafters.


Quoin corners: A decorative brick installation at the corners of brick veneer walls that appear to be columns used to support a building.


Rabbited splices: Splices that are formed by a tongue- and groove-type connection where a joint is formed by sliding several tongues into grooves provided for the purpose.

Rack: (1) A trash rack, usually installed in a waterway. (2) A metal grid that is used to properly space and align floor tiles.

Radiant: A term used to define a means of transferring energy, such as heat, through space.

Raglet: A groove cut in a wall into which the edge of a flashing is turned.

Rag work: In masonry, a term applied to any kind of rubble work made of small thin stones.

Ramset fasteners: A trade name for a power-driven fastener that can be set in concrete, metal, or other hard surfaces. The fasteners are usually driven by an explosive charge.

Rebar: Reinforcing steel rod used in cast concrete to add strength and which resists breaking up of the concrete when stress load is applied to the concrete.

Refloating with asphalt: A term used in repair of a built-up type roof where the assembled membrane is covered with a film of asphalt.

Rehydrate: To return moisture to a substance that has become dehydrated or dried out.

Releveled: When referring to foundations, it indicates that a foundation has been repaired by adjusting the levelness of a foundation.

Rheostat: An electrical device that allows control of voltage to an electrical component.

Rigidity: Resistance to twisting or shearing.

Rime: A rung of a ladder.

Ringed shank nails: Nails that have raised rings around their shafts. The rings engage the grain in wood and help prevent the nails from being pulled from the wood into which they have been driven.

Rise and run: A term used by carpenters to indicate the degree of incline, as in a sloped roof.

Rive: To split lumber along the grain.

Romex electrical wiring (non-metallic sheathed cable): Insulated electrical wiring sheathed in paper and a protective plastic or fabric coating to protect the electrical conductors from being exposed when the wiring is abraded.

Rose: (1) A guard plate or escutcheon between a doorknob and the door, with perforation for the shank. (2) An ornamental centerpiece in a ceiling.

Roughing in: (1) Installation of all concealed plumbing pipes, includes all plumbing work, done before setting of fixtures or finishing, but does not include the fixtures. (2) In electrical and other work, essentially the same process; not finished work.

Router: A tool with a high speed bit that is used, among other things, to shape trim edges and to cut decorative holes in wood surfaces.


Saw kerfs: A gap in material left by the passage of a saw blade through the material.

Schedule 40 PVC: An ASTM designation for PVC plastic pipe that is frequently used for water distribution and drain lines.

Schematic: A line drawing used to define plumbing piping routing, an electrical circuit layout, street layout, or any other planned arrangement.

Scotia: A concave molding with a profile similar to a section of a parabola.

Scratch coat: The first coat of plaster or stucco applied to a surface in three-coat work; usually cross raked or scratched to form a mechanical key with the brown, or second, coat.

Seized or galled threads: A condition where the threads of device have stuck, because the metals making up the threads have fused, so that the male and female portions of the threads cannot pass each other.

Shear, shearing: A term used to indicate relative movement between two surfaces, such as the ceiling and wall of a room or the adjacent walls of a room.

Sheet metal: A relatively thin sheet of metal that can range from a few thousands of an inch thick to about 1/4 in (0.6 cm) thick.

Sheetrock: A trade name for gypsum board (see Gypsum board).

Shim, shimming: A piece of material used as a spacer to keep two surface separated by a desire distance.

Ship lap: Used to describe a horizontal wooden siding applied with the bottom edge of one board having a recessed area along its rear which receives the shaped top-rear edge of the board below it, so as to exclude water during rainfall.

Shore: A temporary support for formwork and fresh concrete, or for recently built structures, that have not developed full design strength; also called prop, tom, post, or strut.

Shotcrete: Mortar or concrete conveyed through a hose and projected at high velocity onto a surface; also known as air-blown mortar, pneumatically applied sprayed mortar, or gunned concrete.

Shot tower (slang): A toilet on a construction job.

Sight glass: A glass window in the liquid line of a refrigerant system that allows one to see if there are vapor bubbles in the liquid refrigerant line. Sight glasses are also used in swimming pool back flush lines and other types of lines or pipes to determine the visible condition of liquids in the lines or pipes.

Silicone: A term that is used to define a rubbery, caulking and sealing materials. The material is also used for cement to hold windows in place and for a multitude of other needs.

Sill plates: The lower plate of a wall that is used to support and hold the components of a wall in place. The sill plate of a wall in a building is usually fastened in place with bolts or Ramset fasteners.

Siphon: The passing of a fluid through a hose, tube, or pipe where the suction left by the passage pulls additional liquid after the flowing liquid.

Skewed: A term used to indicate that two objects do not align, but are oriented in different directions.

Slugger (slang): A tooth on a roll-type rock crusher.

Slurry: A thin, watery mixture of neat cement or cement and sand.

Slurry coat: A brushed application of slurry generally applied to back of adhered veneer units.

Soffit: Area at the underside of the roof overhang between the fascia board and the wall of the structure. Structures without roof overhangs have no soffits.

Solenoid: A relay that is activated by a lower voltage power source to connect a higher voltage and power to a load.

Southern Building Code Congress International (SBCCI): The organization that publishes the Standard Building Code series.

Spaced decking: A term used to define the slats used to support the shingles of a wood shingle roofs.

Spacers: Blocks or shims that are installed between something to maintain a specified distance.

Spalling: To break up into chips or fragments. A term used when paint separates from a surface and falls away in pieces or when concrete breaks up and falls away from a wall or foundation.

Spandrel beams: Beams usually made of concrete that are used as a floor on one side and act as the structural member to support the floor.

Spark arrester: A device normally installed at the outlet of something that can emit sparks. An example is the flue of a fireplace. The spark arrester captures sparks to reduce fire hazard.

Splashblock: A term used to define small concrete troughs that are placed at the base of gutter downspouts to collect rain water and direct it away from the side of a building.

Splashblocks: Blocks placed below the discharge point of a gutter downspout to divert water away from the foundation of a structure. The splashblock reduces the detrimental effects that erosion may have on the performance of a foundation at the discharge point of a gutter downspout.

Splitter box: An electronic device that is used to provide identical electrical signals from a single source to two or more locations.

Spread footing: A generally rectangular prism of concrete larger in lateral dimensions than the column or wall it supports, to distribute the load of a column or wall to the subgrade.

Sprinkle: The distribution of additional chips on a terrazzo topping prior to rolling.

Squeeze blocks: A term used for the blocks installed between floor joists to support the ends of joists against a beam or other wood-support member.

Stiffbacks: Structural members placed across the ceiling joists that span a room to maintain alignment between adjacent joists. Stiffbacks are not support beams and should never be loaded with the roof structure.

Stub-up: A term used to indicate that preparation has been made to install a fixture. An example is that a drain pipe is stubbed up in the floor in preparation for attaching a toilet.

Styrofoam: A type of board-like foam, usually white, frequently used for insulation.

Substrate: A material used below an exposed material (e.g., a built-up roof is installed over a layer of felt paper that is a substrate).

Support, railing: A railing with balusters used to support an upper structure.

Swale: A lengthy depression in the surface of the soil that is like a ditch, but which has sides that are gently sloped away from the center. A swale can carry water away from an area without the ditch feature being apparent.


Tabby: A mixture of stone or shell with mortar; a type of concrete made of lime, gravel, etc.

Take off: A list of materials, by quantities, from information contained in drawings and plans.

Tensile strength: The strength of a material to resist a load that is pulling the fibers of the material apart rather than compressing them.

Terrazzo: A trade name of a surface finish where aggregate is mixed with cement, spread to form a surface, allowed to cure, and then the surface is ground to a polished smooth finish.

Thermocouple: A device used to generate electrical energy to operate safety devices and controls.

Transtra: Horizontal roof timbers.

Traveling nut: A nut that travels along a screw when the screw is turned.

Threshold: The plate at the floor level of a door located between the casing edges that mark the interior from the exterior of the door.

THW or TW Electrical wire: A single strand of insulated electrical wire that must be installed in a protective conduit or container when in use.

Toe-nailed: A means of fastening the end of a plank, such as a floor joist to the side of a beam, with nails where the nails are the only means of supporting the end of the joists.

Tongue-and-groove: A term used for planks in wall siding where the planks are secured together at the edges by a tongue on one side of a plank that is set into the groove of the opposite side of an adjacent plank.


Ultraviolet: A very high frequency light that is beyond the visible range. The light is harmful to people and can cause plastics to age prematurely.

Urea-formaldehyde foam: A foam often used for insulation in walls and or attics. The material is very soft and fragile so it must be protected when in use.

Urethane: A plastic that is often foamed to a shape and allowed to harden. It can be used in a film or sheet for paint, shoe soles, and other such uses.

Usage: The act of using something, such as electrical power. One refers to electrical energy consumption as power usage over a period of time.

U-tie: A wall tie made of heavy wire bent into a U-shape.


Vacuum concrete: Concrete from which water is extracted by a vacuum process before hardening occurs. The concrete reaches its normal 28-day strength in 10 days and has a 25 percent higher crushing strength.

Valleys: A term used in roofing to indicate where two planes of a roof surface come together.

Venturi: A term used to define a shaped restriction in a pipe where a flowing fluid accelerates under pressure to maintain a constant volumetric flow, which is the same as at other locations in the pipe.

Vertex: See crown.

Visqueen vapor barrier: A vapor barrier of polyethylene plastic. The vapor barrier is usually black when used under concrete slabs.

Vitreous clay: A clay with a glazed surface that will not absorb water. Vitreous clay tile liners are usually installed in fireplace flues of site-fabricated fireplaces.


WAG (slang): A wild guess. An estimator's term for a bid put together quickly and without sufficient information.

Wainscot: The wooden paneling of the lower part of an interior wall up to the dado height in a room.

Wall plate: The piece of lumber placed at the top and/or bottom of a wall formed with studs. The sole or lower plate supports the wall and the upper structure of a building. The upper plate is used to support and retain the rafters.

Weather stripping: The material applied the edge of a door or window that is usually flexible and capable of spanning a gap between a door edge and the door casing. The strip of material prevents the entry of air.

Weatherhood: The hood or deflector on a vent opening that is intended to prevent rain water and unconditioned air entry.

Weir: A barrier across a stream of liquid that is used to divert or measure flow per unit of time.

Wellpoint: Perforated pipe sunk into sand to permit the pumping of ground water and excluding the sand.

Wet well: The sump of a pumping station.

Wheelabrating: Shot blasting with steel grit thrown from a fast spinning wheel.


Xs (2Xs 2x4 siding): The X is short for by, such as a 2 by 4 inch plank can be indicated by a 2x4 inch plank.


Y-ball & dog-nuts (slang): Ball clevis and socket eye; used to connect bells and shoes together on overhead distribution lines.

Yeso: A gypsum whitewash widely used in Mexico.

Yield point: That point during increasing stress when the proportion of stress to strain becomes substantially less than it has been at smaller values of stress.

Yield strength: The stress, less than the maximum attainable stress, at which the ratio of stress to strain has dropped well below its value at low stresses, or at which a material exhibits a specified limiting deviation from the usual proportionality of stress to strain.


Z-bar (zee-bar): (1) A Z-shaped bar used as a wall tie. (2) A non-adjustable, Z-shaped sill support bracket. (3) A metal strip to hold carpet next to vinyl.

Zoning permit: A permit issued by appropriate governmental agencies authorizing land to be used for a specific purpose.

Understanding the construction industry is easier when you know the terms and what they mean. Hopefully, our glossary of construction terms answered many of your questions. Have more questions? Visit our loss control and risk management resources area to learn more. Or connect with an American Family Insurance agent.


1. Terms and Definitions. November 18, 2005.

2. National Association of Women in Construction. Construction Dictionary. Phoenix, AR: NAWC, 1994.

3. Professional Engineering Inspections, Inc. Dictionary of Construction Terms. Houston, TX: PEI, 1997.

COPYRIGHT ©2005, ISO Services, Inc.


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