R-value: The thermal resistance of insulation or a glazing system. The R-value is the reciprocal of the U-value. The higher the R-value, the less heat is transmitted throughout the insulation or glazing material.
rabbet: A rectangular, longitudinal groove cut in the corner edge of a board or plank.
raceway: An enclosed channel or conduit designed expressly for holding wires or cables.
radial saw: A circular saw that hangs from a horizontal arm or beam and slides back and forth. The arm pivots from side to side to allow for angle cuts and bevels. When sawing finish plywood, the good side should face up, as the saw cuts on the downstroke.
radiant barrier: Intended to reduce the summer heat gain and the winter heat loss. In new homes, you may see foil-faced wood components at the roof sheathing system installed with the foil facing down into the attic. There may be other areas where the radiant barrier is integrated into the building components and structure of the home. For older homes, a radiant barrier will typically be found stapled across the bottom of some joists. All proper radiant barriers should have a low emittance of 0.1 or less, and a high reflectance of 0.9 or more. The radiant barrier should not be laid on top of the attic floor insulation, or on the attic floor anywhere, because it will soon be covered with dust and will not work.
radiant heating: A method of heating that consists of a forced hot-water system with pipes placed in the floor, wall or ceiling, or using electrically heated panels.
radiation: Describes one method of heating by which a heated surface loses heat to cooler surrounding space or surfaces. The earth receives its heat from the sun by radiation: the heat rays are turned into heat as they strike an object that absorbs some or all of the heat transmitted.
radiator: A heating unit that is supplied heat through a hot water system.
radon: A naturally-occurring radioactive gas found in soil that is heavier than air. Radon gas exposure in abnormally high levels is associated with lung cancer. Mitigation measures may involve crawlspace and basement venting and installation of various forms of vapor barriers and fans.
radon mitigation system: A ventilation system installed beneath the floor of a basement and/or structural wood floor designed to exhaust radon gas to the exterior of a home.
rafter: A sloping roof member that supports the roof covering which extends from the ridge or the hip of the roof to the eaves. A common rafter is one that runs square with the plate and extends to the ridge. A hip rafter extends from the outside angle of the plate toward the apex of the roof, and is 2 inches deeper or wider than a common rafter. A valley rafter extends from an inside angle of the plates toward the ridge of the house.
rafter tail: The portion of a rafter that extends past the building to form the eaves.
rafter, hip: A rafter that forms the intersection of an external roof angle.
rafter, valley: A rafter that forms the intersection of an internal roof angle. The valley rafter is normally made of double 2-inch-thick members.
raggle block: A specially-designed masonry block having a slot or opening into which the top edge of the roof flashing is inserted and anchored.
rail: Cross-members of panel doors or a sash. Also, the upper and lower members of a balustrade or staircase extending from one vertical support to another, such as a post.
railroad tie: Black-tar and preservative-impregnated wooden timbers that are 6x8 inches and 6 to 8 feet long that are used to hold railroad track in place. Also used as a member of a retaining wall.
rake: A trim member that runs parallel to the roof slope and forms the finish between the wall and a gable roof extension. The angle of slope of a roof rafter, or the inclined portion of a cornice.
rake edge: The overhang of an inclined roof plane beyond the vertical wall below it.
rake fascia: The vertical face of the sloping end of a roof eave.
rake siding: The practice of installing lap siding diagonally.
ramp: A sloped walking surface used for wheelchair access.
ranch: Describes a single-story, one-level home style of home.
random-tab shingles: Shingles whose tabs vary in size and exposure.
Rankine: A thermodynamic (absolute) temperature scale whose degree is defined as equal to one degree Fahrenheit.
raw linseed oil: A drying oil processed from flaxseed that polymerizes into a solid form and used in resins, solvents, varnish in wood finishing, pigment binder in oil paints, and plasticizer and hardener in putty and in the manufacture of linoleum.
re-glaze: To replace a broken window.
readily accessible: Describes the area of a subject property that has been made available to the inspector at the time of the walk-through survey portion of the inspection, and/or a system or component that, in the judgment of the inspector, is capable of being safely entered and observed without the need of portable ladders, the removal of obstacles, the detachment or disengagement of connecting or securing devices, or other unsafe or difficult procedures to gain access, and/or a document that has been made available to the inspector for use in the research portion of a commercial property inspection.
readily ascertainable: Describes information that is available to the inspector within a reasonable time at a nominal cost so that it can be practically reviewed during the research portion of a commercial property inspection.
readily available: Describes the information, personnel and/or documents that are made immediately available to the inspector for the research portion of a commercial property inspection.
ready-mixed concrete: Concrete mixed at a plant or in trucks en route to a job and delivered ready for placement.
rebar: Nickname for reinforcing bar that is used to increase the tensile strength of concrete.
receptacle: An electrical outlet. A typical household has several 120-volt receptacles for plugging in lamps and appliances, and 240-volt receptacles for the range, clothes dryer, air conditioners, etc.
recording fee: A fee charged for recording the transfer of a property and paid to a city, county, or appropriate branch of government.
recreational facilities: Spas, saunas, steam baths, swimming pools, tennis courts, playground equipment, and other exercise, entertainment or athletic facilities.
redline (red-lined prints): Blueprints that reflect changes that are marked with red pencil; to indicate changes on blueprints using red pencil.
reducer: See bushing.
reflective glass: Glass with a metallic coating that reduces solar heat gain.
reflective insulation: Sheet material with one or both faces having comparatively low heat emissivity, such as aluminum foil. When used in building construction, the surface faces an air space, reducing the heat radiating across the air space.
refrigerant: A substance that remains a gas at low temperatures and pressure and can be used to transfer heat. Freon used in air-conditioning systems is a refrigerant.
register: A fixture through which conditioned air flows. In a gravity heating system, it is located near the baseboard. In an air-conditioning system, it is located close to the thermostat.
Registered Engineer: A person licensed to practice engineering or architecture in a state, and subject to all laws and limitations imposed by the state's Board of Engineering and Architecture Examiners, and who is engaged in the professional practice of rendering services or creative work requiring education, training and experience in engineering sciences and the application of special knowledge of the mathematical, physical and engineering sciences in such professional or creative work as consultation, investigation, evaluation, planning or design, and supervision of construction for the purpose of securing compliance with specifications and design for any such work.
reglet: A horizontal slot, formed or cut in a parapet or other masonry wall, into which the top edge of counter-flashing is inserted and anchored. In glazing, a reglet is a pocket or keyway extruded into the framing for installing the glazing gaskets.
reinforced concrete: A combination of steel and concrete using the best properties of both. The steel consists of rebar from 3/8-inch to 2-1/4 inches in diameter and is placed before the concrete is poured.
reinforced masonry: Masonry units, reinforcing steel, grout and/or mortar combined to act together to strengthen a masonry structure.
reinforcing bar (rebar): Steel rods or metal fabric placed in concrete slabs, beams or columns to increase their strength.
relative heat gain: The amount of heat gain through a glass product, taking into consideration the effects of solar heat gain (shading coefficient) and conductive heat gain (U-value).
relative humidity (RH): The amount of water vapor in the atmosphere expressed as a percentage of the maximum quantity that could be present at a given temperature. The actual amount of water vapor that can be held in space increases with the temperature.
release tape: A plastic or paper strip that is applied to the back of self-sealing shingles designed to prevent them from sticking together in the bundles; need not be removed for application.
remaining useful life: A subjective estimate or educated guess made by the inspector based upon his/her observations and experience as to the number of years that a component will continue to be functional before needing replacement.
remote: Remote digital readouts that are installed near the front of a house that allow utility companies (electrical, gas, water) to easily read the homeowner's usage of the service.
removable: Capable of being opened, dislodged or transferred to another location easily.
repair: The reconstruction or renewal of any part of an existing item, component, system or structure.
replacement air: Air deliberately brought into a structure to compensate for the air being consumed or expelled.
repoint (re-point): To repair the mortar of masonry joints, such as between the bricks of a chimney, etc.
report (inspection report): The written communication describing the material defects discovered by the inspector based on his/her observations made during a property inspection and, optionally, research conducted by the inspector, all of which, in the inspector's opinion, are likely to be of interest to his/her client. A report may include photos and other images of observations made during the walk-through survey portion of the inspection, and/or copies of documents reviewed during the research portion of a commercial inspection.
representative number: A number sufficient to serve as a typical or characteristic example of the item(s) inspected.
representative sampling: A small quantity of components of any system or structure, enough like others in its class or kind, to serve as an example of its class or kind.
research: The process of gathering information, through the review of documents and interviews, to augment the observations made during the walk-through survey portion of the inspection. This research may include reviewing readily available documents, such as previous inspection reports, building permits, code violation notices, and environmental studies. This research may also include interviews with readily available personnel, such as building managers, tenants and owners.
residential property: A home; in multi-unit housing, four or fewer individual housing units.
residential unit: A home; a single unit providing complete, independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking and sanitation.
resilient flooring: A durable floor covering that has the ability to resume its original shape.
resistance: The internal structure of wires in conductors opposes the flow of electric current and converts some current into heat. This internal, friction-like effect is called resistance and is measured in ohms. Resistance equals voltage divided by amperage.
resorcinol glue: A glue that is high in both wet and dry strength and resistant to high temperatures, and used for gluing lumber and assembly joints that must withstand severe service conditions.
retaining wall: A structure that holds back a slope and prevents erosion.
retentions: Amounts withheld from progress billings until final and satisfactory project completion.
return: In heating and cooling systems, a vent that returns cold air to be warmed. In a hot-air furnace system, the return is located near an inside wall.
ribbon: A 1x4-inch board let into the studs horizontally to support ceiling and second-floor joists. Also called a girt.
ridge: The horizontal line at the junction of the top edges of two sloping roof surfaces.
ridge board (ridgeboard): The horizontal support board placed on edge at the ridge of a roof into which the upper ends of opposing rafters are fastened.
ridge cut: The end cut on a rafter that fits to the ridgeboard.
rigid metal conduit: Conduit that resembles plumbing pipe and encloses wires to protect them from exposure, weather and damage.
rise: In stairs, the vertical height of a step or flight of stairs.
riser: Each of the vertical boards closing the spaces between the treads of stairways.
road base: An aggregate mixture of sand and stone.
rock 1, 2, 3: Referring to drywall, this means to install drywall to the walls and ceilings (with nails and screws), and before taping is performed.
roll roofing: Refers to asphalt roofing material composed of an organic felt or fiberglass mat, saturated with asphalt, and faced with stone aggregate, and supplied in 36-inch wide rolls with 108 square feet of material. Weights are generally 45 to 90 pounds per roll. Inexpensive and commonly used on sloped roofs in North America.
roll, rolling: To install the floor joists or trusses in their correct place. (To roll the floor means to install the floor joists).
Romex®: Brand name for a cable consisting of two or more insulated conductors having an outer sheath of moisture resistant, non-metallic material. The conductor insulation is rubber, neoprene, thermoplastic or a moisture-resistant, flame-retardant fibrous material. Comes in NM and NMC types.
roof assembly: A system designed to provide weather protection that includes the roof covering, underlayment, roof deck, insulation, vapor retarder and interior finish.
roof deck: See deck.
roof sheathing: The boards or sheet material fastened to the roof rafters on which the shingles or other roof covering is laid.
roof system: General term that refers collectively to the waterproof covering, roof insulation, vapor barrier (if used) and roof deck.
roof vent pipe flashing: Used in residential and commercial applications where a watertight seal of roof penetrations around plumbing vent pipes is installed. The flashing material can be made of sloped plastic and metal bases with flexible rubber sealing collars.
roofing tape: An asphalt-saturated tape used with asphalt cements for flashing and patching asphalt roofing.
root cellar: Historically, a food storage area located within a basement or by itself beneath a home, possibly with a dirt floor and separate exterior exit.
rough: In hardware, metal fastenings on cabinets that are usually concealed, such as staples.
rough flooring: Floor sheathing; materials used to form an unfinished floor.
rough opening: The opening in a wall into which a door or window is to be installed.
rough plumbing: All plumbing that is done before the finish trades (sheetrock, painting, etc.), including all waste lines and supply water lines that are in the walls or framing of the building.
RPM: Revolutions per minute.
rubber emulsion paint: Paint having a latex binder.
rubber-tired roller: A roller with rubber tires commonly used for compacting trimmed subgrade, aggregate base and clay-type soils.
rubbish: Waste materials other than garbage, such as discarded and leftover building materials, packaging, etc.
run (roofing): The horizontal distance between the eaves and the ridge of the roof, being half the span for a symmetrical gable roof. Also, the net width of a step or the horizontal distance covered by a flight of stairs.