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.
cat’s paw: A variation of a pry bar used to pry up deep-set or counter-sunk nails.
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.
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.
cells (masonry): The hollow spaces in concrete blocks.
cellulose insulation: Ground-up newspaper that is treated with fire-retardant.
Celotex: UK-based brand of black fibrous board that is used as exterior sheeting.
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.
Certificate of Occupancy (CO): A document stating that a building is approved for occupancy. The building authority issues the Certificate of Occupancy.
certified: Having a formal document testifying to the qualification or completion of requirements.
Certified Commercial Inspector (CCI)®: A professional designation and a U.S. federal certification mark administered by InterNACHI, the International Association of Certified Home Inspectors.
Certified Professional Inspector (CPI)®: A professional designation and a U.S. federal certification mark administered by InterNACHI, the International Association of Certified Home Inspectors.
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.
chalk line: A line made on the roof by snapping a taut string or cord dusted with chalk and used for alignment purposes.
change order: A written document that modifies the plans and specifications and/or the price of a construction contract.
channel glazing: The installation of glass products into U-shaped glazing channels. The channels may have fixed stops; however, at least one glazing stop on one edge must be removable.
chapter: A local group of members of a larger association, as in a local InterNACHI chapter; a local branch.
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.
chink: To install fiberglass insulation around all exterior door and window frames, wall corners, and small gaps in the exterior wall. A narrow opening, such as a crack or fissure; to create a narrow opening, such as a crack or fissure. To fill the chinks of, as with caulking.
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 andwaferboard.
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.
cistern: A reservoir or storage tank used for a household’s water supply.
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 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.
clip ties: Sharp, cut metal wires that protrude out of a concrete foundation wall that formerly held the foundation form panels in place.
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 auger: A flexible rod with a curved end used to access a toilet’s built-in trap and remove clogs.
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.
CO: The chemical formula for carbon monoxide, and the acronym for Certificate of Occupancy.
coal tar: A viscous, liquid mixture of hydrocarbon compounds, derived (along with coke) from the destructive distillation of coal.
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.
Code of Ethics: Ethical standards of conduct for home inspectors.
code official: The officer or other government-designated authority charged with the enforcement of local building codes.
coefficient of performance (COP): A measure of efficiency in a furnace or HVAC system\’s heating mode that represents the ratio of total heating capacity to electrical energy input. For example, if a heating system has a COP of 3, it will deliver 3 units of energy for every 1 unit of electricity consumed.
cohesive failure: Internal splitting of a compound resulting from over-stressing of the compound.
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.
cold-applied: Describes products that can be applied without heating. These differ from products that need to be heated before being applied.
cold-method or lap cement: Special multipurpose adhesive for low-sloped, cold-applied roof construction. Bonds 19-inch selvedge, mineral surface and cap sheets to the underlayment. Doubles as an adhesive on 2-inch selvedge lap of mineral-, granule- or smooth-surfaced roofing. Available in both summer and winter grades.
cold-process adhesive: Mastic prepared with SBS modifiers to adhere laps, flashing and joints of built-up or low-slope roofing without hot-mopping or torching equipment.
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.
combination doors or windows: Combination doors or windows are used over regular openings to provide winter insulation and summer protection. They typically have self-storing or removable glass and screen inserts, which eliminates the need for handling a different unit each season.
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 cooking appliances: Appliances used in a commercial food-service establishment for heating and/or cooking food.
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.
compatible: Two or more substances that can be mixed or blended without separating, reacting or affecting either material adversely.
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 set: The permanent deformation of a material after removal of the compressive stress.
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.
ComSOP: International Standards of Practice for Inspecting Commercial Properties.
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.
condition: The plainly visible and conspicuous state of being of a material object.
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 Restrictions (CC&Rs): 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.
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 air 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 contract: A legal document that specifies the details of a construction project. A desirable construction contract includes: the contractors’ license/registration number; a statement of work quality, such as “Standard Practices of the Trades” or “according to manufacturers’ specifications”; a set of blueprints or plans; a set of specifications; any allowances; a construction timetable, including starting and completion dates; a fixed price for the work, or a time-and-materials formula; a payment schedule; a written warranty; and a clause that outlines the methods for resolving any disputes that arise.
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.
construction loan: A loan provided by a lending institution specifically to construct or renovate a building.
consultant: A person with expertise in a particular area who assists the inspector with specific portions of a commercial property inspection.
contamination: An impairment of the quality or tainting of the potable water supply.
Continuing Education: Ongoing training and education, often recognized and accredited by state and other governmental agencies, and typically a requirement for membership in a home inspection association, such as InterNACHI’s Continuing Education policy and requirements.
continuity tester: An electrical tool used to identify and diagnose a circuit as either open or closed.
contractor: An individual licensed to perform certain types of construction activities. In most states, the general contractor’s license and some specialty contractors’ licenses don’t require compliance with bonding, workers’ compensation or similar regulations. Some of the specialty contractor licenses involve extensive training, testing and/or insurance requirements. There are various types of contractors, including the general contractor, who is responsible for the execution, supervision and overall coordination of a project, and may also perform some of the individual construction tasks. Most general contractors are not licensed to perform all specialty trades and must hire specialty contractors for such tasks, such as electrical and plumbing. A remodeling contractor is a general contractor who specializes in remodeling work. A specialty contractor is licensed to perform a specialty task, such as electrical, side sewer, or asbestos abatement. A sub-contractor is a general or specialty contractor who works for another general contractor.
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.
conventional loan: A mortgage loan that is not insured by a government agency, such as the FHA or VA.
convertibility: The ability to change a loan from an adjustable-rate schedule to a fixed-rate schedule.
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.
cooling tower: A large device mounted on a roof and consisting of several baffles over which water is pumped in order to reduce its temperature.
coped: Removing the top and bottom flange of the end(s) of a metal I-beam to permit it to fit within and become bolted to the web of another I-beam in a “T” arrangement.
coped joint: Cutting and fitting woodwork to an irregular surface.
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.
Cornerite™: Metal mesh lath cut into strips and bent to a right angle used in interior corners of walls and ceilings on lath to prevent cracks in plastering.
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.
cost breakdown: A breakdown of all the anticipated costs on a construction or renovation project.
cost plus contract: See time and materials contract.
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.
covenants: Rules usually developed by a builder or developer regarding the physical appearance of buildings in a particular geographic area. Typical covenants address building height, appropriate fencing and landscaping, and the type of exterior material (stucco, brick, stone, siding, etc.) that may be used.
coverage: The amount of weather protection provided by the roofing material that depends on the number of layers of material between the exposed surface of the roofing and the deck (single coverage, double coverage, etc.).
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.
crazing: A series of hairline cracks in the surface of weathered materials having a web-like appearance. Also, hairline cracks in pre-finished metals caused by bending or forming. See also brake metal.
credit rating: A report ordered by a lender from a credit agency to determine a borrower’s credit habits.
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.
crock: Crockery or cement or other container used in the ground to hold water for pumping sump pumps.
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.
CSA: Canadian Standards Association.
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.
curing agent: One part of a multi-part sealant that, when added to the base, causes the base to change its physical state via chemical reaction.
curtain drain: A ditch, sometimes filled with gravel, and a drain tile that diverts storm and rainwater away from a structure.
curtain wall: A thin wall supported by the structural steel or concrete frame of a building independent of the wall below. Also, an aluminum framing system on the face of a building containing vision glass panels and spandrel panels made of glass, aluminum or other material.
cut-in brace: Nominal 2-inch-thick members, usually 2x4s, cut in between each stud diagonally.
cutback: In roofing, basic asphalt or tar which has been “cut back” with solvents and oils so that the material becomes fluid.
cutoff: A piece of roofing membrane consisting of one or more narrow plies of felt that is usually hot-mopped to seal the edge of insulation.
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.