top of page

Below are terms related to homes and their systems and components. You may encounter these terms in your Home Inspection Report or when communicating with other inspectors or contractors about your home.


caisson: A 10- or 12-inch-diameter hole drilled into the earth and embedded into bedrock 3 to 4 feet. The structural support for a type of foundation wall, porch, patio, monopost, or other structure. Two or more sticks of reinforcing bars (rebar) are inserted into and run the full length of the hole, and concrete is poured into the caisson hole.


camber window: A casement window with a curved top.


cant strip: A beveled support used at the junction of a flat surface and a vertical surface to prevent bends and/or cracking of the roofing membrane at the intersection of the roof deck and wall. Used with a base flashing to minimize breaking of the roofing felts.


cantilever: A projecting beam or other structure supported at only one end. Any part of a structure that projects beyond its main support and is balanced on it.


cap: The upper member of a column, pilaster, door cornice, molding, and similar components.

cap flashing: The portion of the flashing attached to a vertical surface used to prevent water from migrating behind the base flashing.


cap sheet: A top layer in built-up roofing.


cap sheets: In roofing, one to four plies of felt bonded and top-coated with bitumen that is laid over an existing roof as a treatment for defective roofs.


carbon monoxide (CO): A colorless, odorless, highly poisonous gas formed by the incomplete combustion of carbon.


carbon-monoxide (CO) detector: A device that detects the presence of carbon monoxide gas and sounds an alarm in order to alert occupants of unsafe levels. Many models also have smoke alarms as a dual feature. CO detectors may be solely battery-operated or may be hard-wired into a structure's electrical system, with batteries as a backup power source.


casement frames and sash: Frames of wood or metal enclosing part or all of the sash, which may be opened by means of hinges affixed to the vertical edges.


casement window: A side-hinged window that opens on hinges secured to the side of the window frame.


casing: Molding of various widths and thicknesses used to trim door and window openings at the jambs.


cast iron: Heavy metal formed by casting on molds. The metal is covered with a porcelain enamel coating to make fixtures, such as the cast-iron tubs.


cast-iron pipe (plumbing): Drain and vent lines. Most older drain-waste venting systems are made of cast-iron pipes, but ABS and PVC are now more popular replacement materials. Cast-iron pipes were originally joined with molten lead, but most plumbers now join them with no-hub couplers.


catch basin: A drain for a low or wet spot, with pipe exiting the side and a pit at the bottom to collect sediment.


caulk: The application of sealant to a joint, crack or crevice. A compound used for sealing that has a minimum capability of joint movement. Sometimes called low-performance sealant.


caulking: Material used to seal exterior cracks and openings, such as at windows or foundations.


CCA (chromated copper arsenate): A pesticide that is forced into wood under high pressure to protect it from termites and other wood-boring insects, as well as decay caused by fungus.

CC&Rs (Conditions, Covenants & Restrictions): The standards that define the manner in which a property may be used and the protections the developer provides for the benefit of all owners in a subdivision.


ceiling joist: One of a series of parallel framing members used to support ceiling loads and supported, in turn, by larger beams, girders or bearing walls. Also called roof joist.


cellulose insulation: Ground-up newspaper that is treated with fire-retardant.


cement: The gray powder that serves as the glue in concrete; Portland cement; also, any adhesive.


cement mixtures: Cement mixtures are labeled with their ratios of cement to sand to aggregate. A rich cement mixture consists of one part cement, two parts sand and three parts coarse aggregate, and is commonly used for concrete roads and waterproof structures. A standard cement mixture consists of one part cement, two parts sand and four parts coarse aggregate, and is used for reinforced work floors, roofs, columns, arches, tanks, sewers, conduits, etc. A medium cement mixture consists of one part cement, 2-1/2 parts sand and five parts coarse aggregate, and is used for foundations, walls, abutments, piers, etc. A lean cement mixture consists of one part cement, three parts sand and six parts coarse aggregate, and is used for all mass concrete work, large foundations, backing for stone masonry, etc.


center-set: A style of faucet that is installed on a lavatory with 4-inch center-to-center faucet holes and having the spout and handle(s) combined into a single part.


ceramic disk valve: A type of valve that relies on two-part revolving disks in a sealed cylinder. Each disk has a port in it that, when aligned with the other, allows water to pass through.


ceramic tile: A man-made or machine-made clay tile used to finish a floor or wall. Generally used in bathtub and shower enclosures and on countertops.


CFM (cubic feet per minute): Measure of a volume of air. When testing systems, the CFM can be found by multiplying the face velocity, or amount of air passing through the face of an outlet or return, multiplied by the free area, or the total area of the openings in the outlet or inlet through which air can pass, in square feet.


chair rail: A molding that runs horizontally along the wall at about 3 feet from the ground. In storefront, window wall or curtain wall systems, a chair rail is an aluminum extrusion applied horizontally to the inside of the system 3 feet from the floor to create a barrier in floor-to-ceiling glazing applications.


chase: A framed, enclosed space around a flue pipe or a channel in a wall or through a ceiling for something to lie in or pass through.


checking: Fissures that appear with age in many exterior paint coatings. At first, it is superficial but, in time, it may penetrate entirely through the coating. It produces a pattern of surface cracks running in irregular lines. When found in the top pour of an asphalt built-up roof, checking is the preliminary stage of alligatoring.


checkrails (check rails): The meeting rails that are sufficiently thicker than a window used to fill the opening between the top and bottom sash made by the parting stop in the frame of double-hung windows. They are usually beveled with a diagonal or rabbeted overlap.


chemical-injection grouting: Leak-repair technique usually used below grade in cracks and joints in concrete walls and floors; involves the injection of sealant (usually urethane) that reacts with water to form a seal.


chimney: A structure containing one or more flues for removing gases to the outside atmosphere.


chipboard: A manufactured wood panel made out of 1- to 2-inch wood chips and glue, often used as a substitute for plywood in the exterior wall and roof sheathing. Also called OSB (oriented strand board), flakeboard and waferboard.

chlorinated polyvinyl chlorideSee CPVC.


circuit: A network of wiring that typically starts at a panel box, feeds electricity to receptacles/outlets, and ultimately returns to the panel box.


circuit breaker: A protective device that automatically opens an electrical circuit when it is overloaded.


cladding: Something that covers or overlays; term used to describe the exterior wall covering, as well as the metal components cover windows, doors and/or fascia for weather protection.


Class A fire resistance: The highest fire-resistance rating for roofing, per the ASTM E-108, and indicates that roofing is able to withstand severe exposure to fire originating from sources outside the building.


Class B door: A fire-resistance rating applied by the Underwriters Laboratories for a door having a one to 1-1/2 hour rating, which indicates that the door will withstand a fire for one to 1-1/2 hours, as well as restrict the travel of smoke.


Class B fire resistance: Fire-resistance rating that indicates that roofing material is able to withstand moderate exposure to fire originating from sources outside the building.


Class C fire resistance: Fire-resistance rating that indicates that roofing material is able to withstand light exposure to fire originating from sources outside the building.


cleanout: A plug in a trap or drainpipe that provides access for the purpose of clearing an obstruction.


cleanout (plumbing): A wye or tee drain fitting with a removable plug that permits inspection and access for an auger or snake.


clearance: The minimum distance through air measured between the surface of something heat-producing and the surface of something combustible.


clearly identifiable: Capable of being recognized by a person of normal vision.


cleat: A wedge-shaped piece of metal or wood that serves as a support or check; a strip fastened across something to give it strength or hold it in position.


client: The party that retains the services of the inspector and pays for the inspection.


closed-cut valley: A method of valley treatment by which shingles from one side of the valley extend across the valley, while shingles from the other side are trimmed 2 inches from the valley centerline. The valley flashing is not exposed.


closet bend: A curved fitting that connects a closet flange to a toilet drain.


closet bolt: A bolt whose head is fitted to a closet flange and protrudes up through a toilet base. A nut is tightened around it on the toilet base. Two or four bolts serve one toilet.


closet flange: An anchoring ring secured to the floor to which the base of a toilet is secured using bolts.


coal tar pitch: A bituminous material that is a byproduct of the coking of coal and used as the waterproofing material for tar and gravel built-up roofing.


cold patch: In roofing, a roof repair done with cold-applied material.


cold-air return: The ductwork and related grilles that carry room air back to the furnace for re-heating.


collar: In roofing, a conical metal cap flashing used in conjunction with vent pipes or stacks, usually located several inches above the plane of the roof, for the purpose of shedding water away from the base of the vent.


collar beam: In carpentry, a tie that keeps the roof from spreading. They serve to stiffen the roof structure. Connects similar rafters on opposite sides of the roof.


collar tie: A horizontal board attached perpendicular to rafters.


column: In architecture, a perpendicular supporting member, circular or rectangular in section, usually consisting of a base, shaft and capital. In engineering, a vertical structural compression member that supports loads acting in the direction of its longitudinal axis.


combustible: Describes any material that will burn.


combustion air: The ductwork installed to bring fresh outside air to the furnace and/or hot water heater. Normally, two separate supplies of air are brought in: one high and one low.


combustion chamber: The part of a boiler, furnace or wood stove where the burn occurs; normally lined with firebrick or molded or sprayed insulation.


commercial property: The building structures and improvements located on a parcel of commercial real estate. These may include structures such as buildings with residential units operated for profit, mixed-use buildings, strip malls, motels, factories, storage facilities, restaurants, and office buildings.


common rafter: Rafter that extends from the top plate to the ridge. Generally set 12, 16 or 24 inches apart.


component: A permanently installed or attached fixture, element or part of a system.


composite board: An insulation board that has two different insulation types laminated together in two or three layers.


compression fitting: Used to join or connect pipes and conduit by causing a ring to compress against the connecting tube when tightened with a wrench.


compression gasket: A gasket designed to function under compression.


compression valve: A type of valve that works by raising or lowering a stem. Water passes through the valve by turning the faucet handle, which causes the stem to drop or rise.


compression web: A member of a truss system that connects the bottom and top chords, providing downward support.


compressor: A mechanical device that pressurizes a gas in order to turn it into a liquid, thereby allowing heat to be removed or added. A compressor is the main component of conventional heat pumps and air conditioners. In an air-conditioning system, the compressor normally sits outdoors and has a large fan to remove heat.


concealed: Rendered inaccessible by the structure or finish of the building. Wires in concealed raceways are considered concealed, even though they may become accessible by withdrawing them.


concealed nail method: Application of roll roofing by which all nails are driven into the underlying course of roofing and covered by a cemented, overlapping course. Nails are not exposed to the weather.


concrete (plain): Concrete without reinforcement or reinforced only for shrinkage or temperature changes.


concrete block: A hollow concrete brick that is typically 8x8x16 inches in size and often used in low-rise commercial and some residential construction. The original design and use is attributed to the architect Frank Lloyd Wright.


concrete board (or Wonderboard®): A panel made of concrete and fiberglass that is usually used as tile-backing material.


concrete grout: A mixture of 3/8-inch pea gravel, sand, cement and water that is poured into the cells of concrete-block walls to reinforce them.


condensate line: The copper pipe that runs from the outside air-conditioning condenser to the inside furnace, where the A/C coil is located.


condensation: Water accumulation or sweat on walls, ceiling and pipes, which is normal in areas of high humidity, and usually controlled by ventilation or a dehumidifier.


condensing unit: The component of a cooling system located outdoors, which includes a compressor and condensing coil designed to give off heat.


conditioned space: The sections of a house that are intentionally heated and/or cooled and surrounded by a continuous thermal envelope, which includes an air barrier and thermal barrier. For example, an attic is an unconditioned space if it is vented and has insulation on its floor. An unvented attic with insulation along the attic slopes is part of the conditioned space.


Conditions, Covenants and RestrictionsSee CC&Rs.


conduction: The flow of heat from one part of a substance to another part. A piece of iron with one end placed in a fire will soon become warm from end to end due to the transfer of heat by the actual collision of the molecules.


conductivity: The rate at which heat (energy) is transmitted through a material.


conductor: In roofing, a pipe for conveying rainwater from the roof gutter to a drain, or from a roof drain to the storm drain; also called a leader, downspout or downpipe. In electrical contracting, a wire through which a current of electricity flows, better known as an electric wire.


conductor (electrical): Anything that conducts or carries electricity.


conduit: Tubing or hollow pipe casing through which electrical lines run.


connector: The pipe that connects a fuel-burning appliance to a chimney.


console lavatory: A table-like lavatory whose basin is attached to a wall at the back and by table or piano legs at the front.


construction (frame-type): A type of construction by which the structural parts are wood or depend upon a wood frame for support. In building codes, if masonry veneer is applied to the exterior walls, the classification of this type of construction is usually unchanged.


construction adhesive: Thick-bodied adhesive suited to a wide range of repair and construction tasks and packaged in convenient cartridges for use in caulking guns.


construction drywall: A type of construction by which the interior wall finish is applied in a dry condition, generally in the form of sheet materials or wood paneling, as opposed to plaster.


contamination: An impairment of the quality or tainting of the potable water supply.


control joint: A control joint controls or accommodates movement in the surface component of a roof.


convection: A method of transferring heat by the actual movement of heated molecules, usually by a freestanding unit, such as a furnace.


cooling load: The amount of cooling required to keep a building at a specified temperature during the summer, usually 78° F, regardless of outside temperature.


coping: A construction unit placed at the top of a parapet wall to serve as a cover for the wall.


coping joint: The intersection of a roof slope and an exterior vertical wall.


copper pipe types: Type K is identified by a green stripe and has the heaviest or thickest wall and is generally used underground. Type L is identified by a blue stripe and has a medium wall thickness and is most commonly used for water service and for general interior water piping. Type M is identified by a red stripe and has a thin wall, and many codes permit its use in general water piping installation.


corbel: The triangular, decorative and supporting member that holds a mantel or horizontal shelf.


corbel out: To build out one or more courses of brick or stone from the face of a wall to form a support for timbers.


core: A small section cut from any material to show its internal composition.


corner bead: A strip of formed sheet metal, sometimes combined with a strip of metal lath, placed on corners before plastering to reinforce them. Also, a strip of 3/4-round or angular wood finish placed over a plastered corner for protection.


corner boards: Used as trim for the external corners of a house or other frame structure against which the ends of the siding are finished.


corner braces: Diagonal braces at the corners of frame structure to stiffen and strengthen the wall.


cornice: A horizontal projecting course on the exterior of a building, usually at the base of a parapet. In residential construction, the overhang of a pitched roof at the cave line, usually consisting of a fascia board, a soffit for a closed cornice, and appropriate moldings.


cornice return: The portion of the cornice that returns on the gable end of a house.


corrosion: The deterioration of metal by chemical or electrochemical reaction resulting from exposure to weathering, moisture, chemicals or other agents or media.


corrugated: Folded or shaped into parallel ridges or furrows so as to form a symmetrically wavy surface.


cosmetic defect: A superficial flaw or blemish in the appearance of a system or component that does not interfere with its safety or functionality.


counter-flashing: The formed metal secured to a wall, curb or rooftop unit used to cover and protect the upper edge of a base flashing and its associated fasteners. This type of flashing is usually used in residential construction on chimneys at the roofline to cover shingle flashing and to prevent moisture entry.


counterfort: A foundation wall section that strengthens (and is generally perpendicular to) a long section of foundation wall.


coupling: In plumbing, a short collar with only inside threads at each end for receiving the ends of two pipes that are to be fitted and joined together. A right/left coupling is one type used to join two gas pipes in a limited space.


course: A single layer of brick, stone or other building material.


cove molding: A molding with a concave face used as trim or to finish interior corners.


CPVC (chlorinated polyvinyl chloride): Rigid plastic pipe used in plumbing and water supply systems, where code permits its use and installation.


crater: Pit in the surface of concrete resulting from cracking of the mortar due to expansive forces associated with a particle of unsound aggregate or a contaminating material, such as wood or glass.


crawlspace: A shallow, open area enclosed within the foundation and located between the ground and the underside of the lowest floor's structural component.


cricket: A peaked saddle construction at the back of a chimney to prevent the accumulation of snow and ice and to deflect water around the chimney.


cripple stud: Short stud used as support in wall openings that replaces a normal 93-inch or 96-inch stud.


cripple walls: In a wood-frame house, the section of wall under the house between the concrete foundation and the floor joists; also called crawlspace walls.


cross tee (cross-T): Short metal T-beam used in suspended-ceiling systems to bridge the spaces between the main beams.


cross-bridging: Diagonal bracing between adjacent floor joists placed near the center of the joist span to prevent joists from twisting.


cross-connection: Any connection between two otherwise separate piping systems, one of which contains potable water and the other that contains something which could contaminate the potable water.


cross-cutting: Cutting across the wood grain; to cross-cut a board is to cut across its width.

crown: The sloped top of a masonry chimney designed to shed water away from the flue; also called a splay or a wash.

crown molding: A molding used on a cornice or wherever an interior angle is to be covered.

culvert: A round, corrugated drainpipe, normally 15 or 18 inches in diameter, that is installed beneath a driveway parallel to and near the street.


cupola: A small dome at the peak of a pitched roof.

cupping: A type of warping that causes boards to curl up at their edges.

curb: A short wall of masonry built above the level of the roof that provides a means of flashing the deck equipment.

curb roof: A roof with an upper and lower set of rafters on each side whose under-set is less inclined to the horizon than the upper; a mansard roof.

curing (concrete): In concrete applications, the process by which mortar and concrete harden. The length of time is dependent upon the type of cement, mix proportion, required strength, size and shape of the concrete section, weather, and future exposure conditions. The period may be three weeks or longer for lean concrete mixtures used in structures such as dams, or it may be only a few days for richer mixes. Favorable curing temperatures range from 50° to 70° F. Design strength is achieved in 28 days.

curing (paint): The process by which paint bonds to a surface. Curing and drying are not the same.

curtain drain: A ditch, sometimes filled with gravel, and a drain tile that diverts storm and rainwater away from a structure.

cutoff valve: Valve used to shut water off, generally located under a sink and behind the bathtub and shower access panel. It cuts off hot and/or cold water at the source without cutting off the water supply throughout the entire house.

bottom of page