Glossary

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R-Value: A measure of the resistance of an insulating or building material to heat flow, expressed as R-11, R-20, and so on; the higher the number, the greater the resistance to heat flow.

Rabbet: A deep notch formed in or near one edge of a board, framing timber, etc., so that something else can be fitted into it or so that a door or the like can be closed against it.

Radial Saw: A cantilevered circular saw adjustable at various angles to the length of the work and to the perpendicular.

Radiant Heating: Heating a building by radiation from panels containing hot water or electrical heaters.

Radiation: The complete process in which energy is emitted by one body, transmitted through an intervening medium or space, and absorbed by another body.

Radiator: A heating device consisting of a series of connected pipes, typically inside an upright metal structure, through which steam or hot water is circulated so as to radiate heat into the surrounding space.

Radon: A colorless, radioactive, inert gaseous element formed by the radioactive decay of radium. It is used as a radiation source in radiotherapy and to produce neutrons for research.

Radon System: A ventilation system beneath the floor designed to fan radon gas exhaust to the outside of the home.

Rafter: Any of a series of timbers or the like, usually having a pronounced slope, for supporting the sheathing and covering of a roof.

Rafter Tail: The portion of a rafter that extends beyond the building to form the eaves.

Rafter, Hip: The rafter that forms the intersection of an exterior roof angle.

Rafter, Valley: A rafter that forms the intersection of an interior roof angle.

Raggle Block: A groove cut in masonry to receive flashing.

Rail: Any of various horizontal members framing panels or the like, as in a system of paneling, paneled door, window sash, or chest of drawers.

Railroad Tie: One of the cross braces that support the rails on a railway track.

Rake: A board or molding placed along the sloping sides of a frame gable to cover the ends of the siding.

Rake Edge: The overhang of an inclined roof plane beyond the vertical wall attached below it.

Rake Fascia: Any relatively broad, flat, horizontal surface, as the outer edge of a cornice, a stringcourse, etc.

Rake Siding: The process of installing lap siding diagonally.

Ranch: A single story home.

Random-Tab Shingles: Shingles with multiple size tabs.

Rankin: A thermometer on which the units of measurement equals Fahrenheit degrees.

Raw Linseed Oil: A drying oil extracted from flax seed and used in making such things as oil paints.

Ready Mixed Concrete: Pre-mixed concrete ready for placement.

Rebar: A steel bar or rod used to reinforce concrete.

Receptacle: A fitting connected to a power supply and equipped to receive a plug.

Recording Fee: The fee a government charges for reporting a real estate purchase or sale into the public record.

Redline, Red Lined Prints: To mark or designate for cancellation, rejection, dismissal, or the like.

Reducer: Refer to bushing.

Reflective Glass: Glass treated with a metallic coating to reduce heat absorption.

Reflective Insulation: Sheet material with comparatively low heat emissions.

Refrigerant: A cooling substance, as ice or solid carbon dioxide, used in a refrigerator.

Register: A device for controlling the flow of warmed air or the like through an opening, as from a duct to an interior, composed of a number of narrow, parallel blades, usually behind a grating.

Reglaze: To replace a broken window.

Reglet: A groove for guiding or holding a panel, window sash, etc.

Reinforced Concrete: A combination of steel and concrete to add strength.

Reinforced Masonry: Masonry units, reinforcing steel, grout and/or mortar combined to add strength to a masonry structure.

Reinforcing: To strengthen with some added piece, support, or material.

Relative Heat Gain: The amount of heat adsorbed by a glass product.

Relative Humidity: The ratio of the amount of water vapor in the air at a specific temperature to the maximum amount that the air could hold at that temperature, expressed as a percentage.

Release Tape: The strip that is applied to the back of self-sealing shingles.

Remote: Far apart; far distant in space; situated at some distance away.

Resilient Flooring: A durable floor cover.

Resistance: The opposition of a body or substance to current passing through it, resulting in a change of electrical energy into heat or another form of energy.

Resorcinol Glue: A glue designed to work in both wet and dry environments and resistant to high temperatures.

Retaining Wall: A wall built to support or prevent the advance of some mass or water.

Retentions: Involuntary withholdings that are normally eliminated.

Return: In heating and cooling systems, a vent that returns cold air to a heat source to be warmed.

Ribbon (or Girt): A heavy beam, as for supporting the ends of rafters.

Ridge: The horizontal line in which the tops of the rafters of a roof meet.

Ridge Board: The horizontal timber or member at the top of a roof, to which the upper ends of the rafters are fastened.

Ridge Cut: The end cut of a rafter that connects to the ridge board.

Ridgeboards: The horizontal timber or member at the top of a roof, to which the upper ends of the rafters are fastened.

Rigid Metal Conduit: This flexible conduit protects wires from damage.

Rise: The measured height of any of various things, as a roof, a flight of steps, a stair step, or the crown of a road.

Riser: The vertical face of a stair step.

Road Base: A mixture of sand and stone.

Rock 1, 2, 3: A drywall application of installing drywall to the walls and ceilings with nails and screws, before taping is performed.

Roll Roofing: Pre-packaged roofing material.

Roll, Rolling: In roofing, to install the floor joists or trusses.

Romex: A non-metallic cable with two or more insulated conductors having an outer sheath of moisture resistant, non-metallic material.

Roof Deck: Refer to deck.

Roof Sheathing: A layer of boards or of other wood or fiber materials applied to the outer studs, joists, and rafters of a building to strengthen the structure and serve as a base for an exterior weatherproof cladding.

Roof System: A term referring to the waterproof covering, roof insulation, moisture barrier.

Roofing Tape: Tape used for flashing and patching asphalt roofing.

Root Cellar: An underground pit or cellar, usually covered with earth, used for the storage of root crops and other vegetables.

Rough: A term referring to concealed metal fasteners on cabinets, like staples.

Rough Flooring: The materials used to form an unfinished floor.

Rough Opening: The opening in a wall where a door or window will be installed.

Rough Plumbing: All plumbing done before finishing plumbing, sheetrock, painting, etc.

RPM: Revolutions per Minute.

Rubber Emulsion Paint: Paint containing rubber or a rubber like substance which is dispersed in fine droplets of water.

Rubber-Tired Roller: A roller made of rubber tires used for compacting trimmed sub-grade, aggregate base or clay type soils.

Run(Roofing): The horizontal distance between the face of a wall and the ridge of a roof or the distance between the first and last risers of a flight of steps or staircase.