| Term | Definition |
| R | 1. Radius of gyration. 2. Electrical Resistance, in Ohms. |
| R factor or value | A measure of a materials resistance to the passage of heat. New homewalls are usually insulated with 4" of batt insulation with an R value of R-13, and a ceiling insulation of R-30. |
| R Value | A measure of insulation. A measure of a materials resistance to the passage of heat. The higher the R value, the more insulating "power" it has. For example, typical new home's walls are usually insulated with 4" of batt insulation with an R value of R-13 |
| R&D | Research and Development. |
| R-12 | Dichlorodifluromethane. |
| R-Value | The number of minutes (seconds) required for 1 Btu (joule) to penetrate one square foot (square meter) of a material for each degree of temperature difference between the two sides of the material. The resistance of a material to the passage of heat. The |
| RA | 1.Registered Architect. 2. Return Air. |
| Rabbet | A rectangular longitudinal groove cut in the corner edge of a board or plank. |
| Raceway | Any channel courses supporting and protecting electrical conductors, including conduits, wireways, surface metal raceway, cable trays, floor and ceiling raceways, busways, and cable bus. |
| Rack | 1. A framework or stand to support materials or objects. 2. A toothed bar that meshes with a gear wheel as in a Rack and Pinion. |
| Rack and Pinion | A mechanical device consisting of a toothed metal bar (the rack) and a small meshing gear wheel (the pinion). |
| Rack-Type Dishwasher | A dishwasher that accepts dishes which are loaded on metal or plastic racks. |
| Racking | 1. Lateral stresses exerted on an assembly. 2. In bricklaying, the method of laying the end of a wall in a series of steps so when work is resumed at a later date, the bond will continue with the old construction easily. |
| Rad | Radius. |
| Radial | Moving along lines diverging from a center, like spokes. |
| Radial Commutator | Electrical contact surfaces on a rotor which is perpendicular or at right angles to the shaft center line. |
| Radial Wall Form | A temporary structure or mold for the support of a curved concrete wall while the concrete is curing. |
| Radian | A unit of circular angle, equal to an angle at the center of a circle the arc of which is equal in length to the radius; one radian equals 57.2958 degrees; one degree equals 0.017454 radians. |
| Radiant Heat | Heat transmitted by radiation. |
| Radiant Heat Transfer | Radiant heat transfer occurs when there is a large difference between the temperatures of two surfaces that are exposed to each other, but are not touching. |
| Radiant Heating | A heating system in which warm or hot surfaces are used to radiate heat into the space to be conditioned. |
| Radiant Panels | Panels with integral passages for the flow of warm air or liquids; heat is transferred to a room by thermal radiation. |
| Radiation | 1. Heat transformed by electromagnetic waves. 2. A net exchange of radiant energy between two bodies or objects, across an open space. |
| Radiation Unit | A determinate quantity adopted as a standard of measurement of radiant heating. |
| Radiator | A heating device that transfers heat from the heated fluid within to the air outside. |
| Radio Frequency Curing | Of wood adhesives, curing of bondlines by the application of radio frequency energy; also called High Frequency Curing. |
| Radiology Equipment | Apparatus or devices that use high energy radiation in medicine. |
| Radius | A straight line from the center to the circumference of a circle or sphere; one- half of the diameter. |
| Radius of Gyration | A characteristic of the cross-section of the member used in the determination of its structural characteristics. |
| Radon | A heavy radioactive gaseous element formed by disintegration of radium; it seeps out of the earth and accumulates under buildings, in some cases causing cancer in humans; easily removed by passive ventilation. |
| Radon system | A ventilation system beneath the floor of a basement and/or structural wood floor and designed to fan exhaust radon gas to the outside of the home. |
| Raft | A footing or foundation, usually a large thick concrete mat. |
| Rafter | A framing member that runs up and down the slope of a pitched roof; the parallel beams that slope from the ridge of a roof to the eaves and make up the main body of the roof framework. |
| Rafter | Lumber used to support the roof sheeting and roof loads. Generally, 2 X 10's and 2 X 12's are used. The rafters of a flat roof are sometimes called roof joists. |
| Rafter Anchor | A bolt or metal fastening device which attaches the rafters wall plate. |
| Rafter Tie | A wood or steel horizontal tension member connecting two opposite rafters to resist their spreading. |
| Rafter, Common | See Common Rafter. |
| Rafter, Cripple | See Cripple Rafter. |
| Rafter, hip | A rafter that forms the intersection of an external roof angle. |
| Rafter, Jack | See Jack Rafter. |
| 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 | A groove cut in masonry; any groove provided to receive roofing or flashing. |
| Raggle Block | A concrete masonry unit with an integral flashing reglet. |
| Rail | (1) A horizontal bar or timber extending from one post or support to another, such as a guard or barrier in a fence or staircase. (2) The horizontal members of the framework of a sash, door, blind, or any paneled assembly. 3. A horizontal support member t |
| Rail Standard, Steel | See Steel Rail Standard. |
| Rail Transit Boarding Platform | A horizontal, generally level surface, whether raised above, recessed below, or level with a transit rail, from which persons embark/disembark a fixed rail vehicle. |
| Rail, Chair | See Chair Rail. |
| Railing | 1. An open fence or guard for safety, made of rails and posts. 2. A banding in cabinetwork. 3. On plywood, the solid wood band around one or more edges. |
| Railing Expansion Joint | Control joint in metal railing to allow differential movement of railing components from thermal expansion and contraction. |
| Railing Fitting | Elbows, crosses, tees, caps, flanges made of metal, slip type, threaded, or flush welded to railing components to facilitate transitions and terminations. |
| Railing Flange | Flanges made of metal, slip type, threaded, or flush welded to railing components to facilitate attachment to mounting surfaces. |
| Railing, Metal | See Metal Railing. |
| Railing, Pipe | See Pipe Railing. |
| Railing, Structural Tubing | See Structural Tubing Railing. |
| Railroad Crossing | An grade level intersection at which railroad tracks meet vehicular, pedestrian or other kinds of traffic. |
| Railroad Tie | A timber support for railroad tracks. |
| Railroad tie | Black, tar and preservative impregnated, 6" X 8" and 6'-8' long wooden timber that was used to hold railroad track in place. Normally used as a member of a retaining wall. |
| Railroad Work | Construction or repair performed on railroad tracks. |
| Rain Spots | Defects on paint film caused by rain. |
| Raintight | So constructed or protected that exposure to a beating rain will not result in the entrance of water. |
| Raintight Enclosure | A building, a component of a building, or a structure that is impervious to the outside elements such as rain or snow. |
| Raintight Time Clock | A weatherproof time recording clock that has been manufactured to withstand the outside elements, such as rain or snow. |
| Raised Grain | A roughened condition of the surface of dressed lumber in which the hard latewood is raised above the softer earlywood but not torn loose from it. |
| Rake | 1. A hand implement with spaced teeth for gathering or loosening material like grass, gravel, or earth. 2.The sloping edge of a pitched roof. 3. The trim of a building extending in an oblique line, as rake dado or molding. 4. The end of a wall that slopes |
| Rake fascia | The vertical face of the sloping end of a roof eave. |
| Rake Molding | The cornice on the gable edge of a pitch roof, the members of which are made to fit those of the molding of the horizontal eaves. |
| Rake siding | The practice of installing lap siding diagonally. |
| Raked Joint | In brick masonry, a type of joint which has the mortar raked out to a specified depth while the mortar is still green. |
| Raking Bond | Bricks that are laid in a zigzag fashion. |
| RAM | Random Access Memory. |
| Ram Air | Air forced through the condenser due to the rapid movement of the vehicle along the highway. |
| Ramin wood | A popular type of wood used to make wooden blinds. |
| Ramm, Son & Crocker | Fabric vendor with European flair. A division of Robert Allen fabrics. (55 Cabot Blvd., Mansfield, MA 02048) |
| Ramp | A sloping passageway. |
| Ranch | A single story, one level home. |
| Ranch Molding | An architectural style of molding that is installed as finish work or ornamentation; a type or style of trim which is gently curved and devoid of ornate design. |
| Random Access Memory | A memory in a computer system that is used for temporary storage of data and allows that data to be accessed at random and to be changed; compare Read Only Memory. |
| Random Rubble | Masonry wall built of unsquared or rudely squared stones, irregular in size and shape. |
| Random Width Flooring | Flooring materials of wood with varying widths, often called a plank floor. |
| Range | 1. Pressure or temperature settings of a control. 2. Change within limits. 3. A Kitchen Range. |
| Range Hood | An exhaust system installed over a stove to remove fumes by means of a motorized fan and a duct to outside air. |
| Range, Electric | See Electric Range. |
| Range, Firing | See Firing Range, 2. |
| Range, Kitchen | See Kitchen Range. |
| Rankine | A scale for registering temperature in which 0 degrees represents absolute zero; Rankine corresponds to the Fahrenheit scale, 32ø F = 491.67ø Rankine. |
| Rapid Curing (RC) Asphalt | Cutback asphalt composed of asphalt cement and a naphtha or gasoline-type diluent of high volatility. |
| Rapid drawdown | Lowering the elevation of water against a bank faster than the bank can drain leaving a pressure imbalance that may cause the bank to fail. |
| Rapid Sand Filter | A swimming pool filter designed to be used with sand as the filter media and for flows not to exceed 3 GPM per square foot in commercial pools and 5 GPM in residential pools. |
| Rapid Start Lamp | A fluorescent lamp operated by a ballast that provides a low-voltage winding to preheat electrodes and initiate the arc without a starting switch or the application of high voltage. |
| Rare Gas | See Noble Gas. |
| Rasp | A coarse file with cutting points instead of lines. |
| Ratchet | A mechanical device, consisting of a toothed bar and pawl, that allows motion in one direction only. |
| Rate of Flow | Volume flow per unit of time. |
| Rate of Growth | The rate at which a tree has increased its amount of wood; this is measured radially in the trunk or in lumber cut from the trunk; the rate is determined from the number of annual growth rings per inch. |
| Rational Number | Expressible as a ratio of whole numbers, that is, not involving roots or non-terminating decimals; involving only addition, subtraction, multiplication and division and only a finite number of times. |
| Ratproofing | Various measures taken to keep rodents out of the interior of a building, particularly food preparation or storage areas, consisting mainly of steel mesh barriers above and below grade and packing of oversized pipe and conduit holes with cement mortar or |
| Ravelling | In asphalt paving, the progressive separation of aggregate particles from the surface downward or from the edges inward; ravelling is caused by lack of compaction, construction of a thin lift during cold weather, dirty or disintegrating aggregate, too lit |
| Raw | Raw linseed oil. |
| raw edge | The cut edge of fabric, without selvage or hem. |
| Raw Glaze | A ceramic glaze compounded primarily from raw constituents; it contains no pre-fused materials. |
| Raw Linseed Oil | The crude product processed from flaxseed, usually without much further treatment. |
| Raw Oil | Oil as received from the press or separated from the solvent in the solvent extraction process. |
| Raw Sienna | 1. An earthy substance containing oxides of iron and usually of manganese. 2. Brownish yellow pigment, used in paint. 3. See Sienna. |
| Raw Umber | 1. A brown earthy substance containing oxides of iron and manganese. 2. A pigment, darker than ochre and sienna, used in paint. |
| Rayleigh Wave | Forward and vertical vibration of seismic surface wave; see Seismic Wave. |
| Rays, Wood | See Wood Rays. |
| RBM | Reinforced Brick Masonry. |
| RC Asphalt | See Rapid Curing Asphalt. |
| RCP | Reinforced Concrete Pipe. |
| RCSSB | Red Cedar Shake and Shingle Bureau. |
| RDF | Refuse Driven Fuel. |
| Re-Entrainment | Situation that occurs when the air being exhausted from a building is immediately brought back into the system through the air intake and other openings in the building envelope. |
| Re-Entrant Corner | An inside corner of a surface, producing stress concentrations in the roofing or waterproofing membrane. |
| Reach | A section of a stream's length. |
| Reaching | In using a spray gun, extending a spray stroke too far. |
| Reactance | That part of the impedance of an alternating current circuit due to capacitance or inductance or both. |
| Reaction | 1. In structures, the response of the structure to the loads. 2. The force that acts at a support of a structure. |
| Reaction Wood | Wood with more or less distinctive anatomical characters, formed typically in parts of leaning or crooked stems and in branches; in hardwoods this consists of tension wood and in softwoods of compression wood. |
| Reactive Aggregate | See Alkali-Aggregate Reaction. |
| Read Only Memory | A computer memory read only at high speeds but not capable of being changed; compare Random Access Memory. |
| Ready-Mixed | 1. Any material that is mixed prior to delivery to the jobsite. 2. Plaster which is mixed at the mill with mineral aggregate and other ingredients which control time of set; generally used in conjunction with gypsum plasters; also called mill-mixed, pre-m |
| Ready-Mixed Compound | Factory mixed gypsumboard joint compound in ready-to-use form. |
| Ready-Mixed Concrete | Concrete manufactured at batch plants and delivered by truck to the job site in a plastic state. |
| Real Estate | Land that is subject to ownership, with its permanent improvements and appurtenances; also called Real Property. |
| Real Estate Broker | A broker who deals in real property. |
| Real Property | See Real Estate. |
| Realtor | A real estate agent who is a member of the National Association of Realtors. |
| Realty | Real property; real estate. |
| Reamer | A small hand tool for enlarging or shaping holes in wood, metal, or other materials. |
| Reaming | Removing the burr from inside of a pipe. |
| Rear Yard | The space between a building and the rear property line. |
| Reasonable Use | A legal doctrine that allocates water rights. |
| Rebar | Steel reinforcing bar. |
| Rebar, reinforcing bar | Ribbed steel bars installed in foundation concrete walls, footers, and poured in place concrete structures designed to strengthen concrete. Comes in various thickness' and strength grade. |
| Rebate | A continuous rectangular notch cut out of the corner of a piece of wood; a rabbet. |
| Receiver | A person appointed by the court to administer property in foreclosure or a business in reorganization. |
| Receiver Heating Element | Electrical resistance mounted in or around liquid receiver. It is used to maintain head pressures when ambient temperature is low. |
| Receiver-Drier | Cylinder (container) in a refrigerating system for storing liquid refrigerant and which also holds a quantity of desiccant. |
| Receptacle | An electrical outlet. A typical household will have many 120 volt receptacles for plugging in lams and appliances and 240 volt receptacles for the range, clothes dryer, air conditioners, etc. |
| Receptacle, Cable | See Cable Receptacle. |
| Receptacle, Combination | See Combination Receptacle. |
| Receptor | 1. A metallic or nonmetallic waterproof base for a shower stall. 2. A plumbing fixture, such as a floor sink, that receives the discharge from indirect waste piping. |
| Recess | A shallow depth or space in a wall; an alcove or niche. |
| Recess Filler Strip | A strip of material inserted in a fissure to make flush with the surrounding surface. |
| Recessed | Set into a niche or recess in a wall, floor, or ceiling surface. |
| Recessed Edge | In gypsum board, a sharply reduced caliper along the factory edge; has been replaced by the more gradually reduced caliper of the Tapered Edge. See Taper. |
| recessed fitting | Curtain or blind fixed within the recess of a window. |
| Recessed Light Fixture | A light fixture installed in a suspended ceiling or a recess in a plaster or gypsum board ceiling. |
| Reciprocal | 1. Inversely related; opposite; mutually corresponding. 2. One of a pair of numbers whose product is one (8 and 1/8 or 3/4 and 4/3). |
| Reciprocating | Back and forth motion in a straight line. |
| Reciprocating Chiller | A compressor (single-acting) using pistons that are driven by a connecting rod from a crankshaft. |
| Reciprocating Compressor | Compressor which uses a piston and cylinder mechanism to provide pumping action. |
| Reciprocating Single Piston Pump | A pump having a single reciprocating (moving up and down or back and forth) piston. |
| Recirculating Overflow | See Surface Skimmer. |
| Recirculation System | In swimming pool piping, the interconnected system traversed by the recirculated water from the pool until it is returned to the pool. |
| Recision | The cancellation of a contract. |
| Reclamation Tank | See Separation Tank. |
| Recoat Time | In painting, the time interval required between application of successive coats. |
| Reconstruction | The state of being constructed again. |
| Reconveyance Deed | A deed executed by the trustee under a trust deed after the underlying note has been satisfied. |
| Record Drawings | A set of drawings prepared by the general contractor, which includes any revisions in the working drawings and specifications during construction, indicating how the project was actually constructed; sometimes called As-Built Drawings or As-Builts. |
| Recording | The process of placing a document on public record by filing in the office of the county recorder; recording a document constitutes constructive notice. |
| Recording Ammeter | Electrical instrument which uses a pen to record amount of current flow on a moving paper chart. |
| Recording fee | A charge for recording the transfer of a property, paid to a city, county, or other appropriate branch of government. |
| Recording Thermometer | Temperature measuring instrument which has a pen marking a moving chart. |
| Recording Voltmeter | A device which records the continuity, power, grounding, voltage and resistance of electrical circuits. |
| Recourse | 1. The legal right to hold someone liable for payment such as the maker of a negotiable instrument. 2. The provision of some mortgages or trust deeds to hold the borrower personally responsible for the deficit when foreclosure sale proceeds are insufficie |
| Recreational Courts | A quadrangular space walled or marked off for playing games with a ball, such as basketball or tennis. |
| Recreational Facilities | Establishments and structures created for sporting and entertainment purposes, such as courts and pools. |
| Recreational Use Statutes | Laws that have been adopted in most states to protect property owners from liability to persons who are permitted to use the property for recreational purposes. |
| Rectangle | A four sided plane figure whose angles are equal; a parallelogram. |
| Rectifier | A device for converting alternating current to direct current. |
| Rectilinear | Characterized by straight lines; perpendicular. |
| Red Cedar Shake and Shingle Bureau (RCSSB) | 515 116th Avenue NE, Suite 275, Bellevue, Washington 98004, (206) 543-1323, Fax (206) 455-1314. |
| Red Fir | Douglas Fir. |
| Red Label Goods | Flammable or explosive materials with flash points below 80ø F. (26.7ø C.). |
| Red Lead | A compound formed by roasting lead or litharge; it used extensively in paints for protecting iron and steel against corrosion. |
| Red Ochre | An earthy pigment made from impure iron ore, used in paint. |
| Redan | A part of a medieval fortification consisting of two walls or parapets projecting at an acute angle and open to the rear. |
| Redemption | The repurchase of one's property after it has been sold in foreclosure; this right to redeem lapses after a specified time. |
| Redline, red lined prints | Blueprints that reflect changes and that are marked with red pencil. |
| Reducer | 1. A pipe fitting which connects pipes of different sizes. 2. A tile trim unit used to reduce the radius of a bullnose or a cove to another radius or to a square. 3. Volatile ingredients used to thin or lower viscosity of a finishing material. |
| Reducing Female Adapter | A pipe fitting which is threaded on the inside of at least one end to receive a different size pipe, to make a connection. |
| Reducing Flame | An oxygen-fuel gas flame wherein the portion used has a reducing effect; same as Carbonizing Flame. |
| Reducing Tee | A pipe fitting which joins three pipes of different sizes at 90 degree angles. |
| Redundant Member | Any member of a truss not required for truss stability. |
| Redwood | A coniferous timber tree with red heartwood and yellow sapwood. |
| Redwood Inspection Service (RIS) | One Lombard Street, San Francisco, California 94111, (415) 392-7880. |
| reefed curtains | See Italian stringing. |
| reefing | A pair of stationary curtains in which the leading edges are pulled back like theater curtains, by means of diagonally strung cords. |
| Reel | A round device upon which a hose or wire is wound for easy use and storage. |
| Reentrant Angle | An angle pointing inward; the opposite of a salient angle. |
| Refectory | A dining hall. |
| Refinancing | The reorganization of the loans on a property usually by finding new loans at lower interest rates or larger amounts and paying off the old loans. |
| Refined Shellac | A grade of orange or white shellac from which the wax has been removed. |
| Reflectance | The ratio of light reflected by a surface to the incident light falling on the surface. |
| Reflected Ceiling Plan | An architectural drawing of a ceiling seen as though it is reflected from the floor. |
| Reflection | The return of light and sound waves from a surface. |
| Reflection Cracks | Cracks in asphalt overlays that reflect the crack pattern in the pavement structure underneath; caused by vertical or horizontal movement in the pavement beneath the overlay, brought on by expansion and contraction with temperature or moisture changes. |
| Reflection Pool | An ornamental, usually shallow, pool of water designed to reflect an important architectural element beyond. |
| Reflective Coated Glass | Glass onto which a thin layer of metal or metal oxide has been deposited to reflect light and/or heat. |
| Reflective insulation | Sheet material with one or both sun faces of comparatively low heat emissivity, such as aluminum foil. When used in building construction the surfaces face air spaces, reducing the radiation across the air space. |
| Reflective Paint | Paint that has been formulated to reflect light away. |
| Reflector Lamp | Flood lamp or spot with bulb coated with a reflecting surface. |
| Reflector Lighting | A lighting fixture with a polished surface to redirect its light. |
| Reflectorized Sign | A sign made with highly reflective material. |
| Refraction | The bending of a light ray as it passes obliquely through a material. |
| Refractive Index | Ratio of velocity of light in a certain medium compared with its velocity in air under same conditions. |
| Refractories | Heat-resistant non-metallic ceramic materials. |
| Refractory | Capable of enduring high temperature. |
| Refractory Concrete | Concrete having refractory properties, and suitable for use at high temperatures (generally about 315 to 1315ø C), in which the binding agent is a hydraulic cement. |
| Refrigerant | A substance that remains a gas at low temperatures and pressure and can be used to transfer heat. Freon is an example and is used in air conditioning systems. |
| Refrigerant | Substance used in refrigerating mechanism; it absorbs heat in evaporator by change of state from a liquid to a gas, and releases its heat in a condenser as the substance returns from gaseous state back to a liquid state. |
| Refrigerant Charge | Quantity of refrigerant in a system. |
| Refrigerant Control | Device which meters flow of refrigerant between two areas of a refrigerating system; can be a capillary tube, expansion valves, or high and low-side valves; maintains pressure difference between high-pressure and low-pressure side of the mechanical refrig |
| Refrigerant Cylinder | Cylinder in which refrigerant is stored and dispensed; color code painted on cylinder indicates kind of refrigerant. |
| Refrigerated Case | A storage unit using refrigeration to keep food or materials cool. |
| Refrigerated Truck | Commercial vehicle equipped to maintain below-ambient temperatures in its storage compartment.Refrigeration Oil.Specially prepared oil used in refrigerator mechanism which circulates, to some extent, with refrigerant. |
| Refrigeration | The cooling of a material or space. |
| Refrigeration Tubing | The hollow, cylindrical piping which holds the refrigerant fluid in a refrigeration system. |
| Refrigerator, Blood | See Blood Refrigerator. |
| Refuse Driven Fuel (RDF) | A method of recovering heat, in an incinerator, from solid waste. |
| Refuse Hopper | A funnel-shaped receptacle having a device for releasing waste materials through a pipe. |
| Regional Shopping Center | A large shopping center serving a region. |
| Register | A grill placed over a heating duct or cold air return. |
| Register | Combination grille and damper assembly covering an air opening or the end of an air duct. |
| Register, Wall | Awall mounted grille or damper for the passage of conditioned air. |
| Registered Architect | An architect who is registered with the state board of architectural examiners of one of the states; a licensed architect. |
| Reglaze | To replace a broken window. |
| Reglet | A horizontal or sloping slot in masonry construction, or a sheetmetal slot in plastered wood construction, to accept the upper edge of counterflashing. |
| Regular Core Gypsumboard | Gypsumboard for general construction purposes without special core additives. |
| Regulations | Laws that are enacted by a public administrative agency, rather than by an elected legislative body. |
| Regulator | A device for controlling the delivery of gas at some substantially constant pressure regardless of variation in the higher pressure at the source. |
| Rehabilitation | The remodeling of a building to render it suitable for modern uses. |
| Rehydrate | To provide water to something that is dehydrated. |
| Reinforced Brick Masonry (RBM) | Brickwork into which steel bars have been embedded in the mortar to impart tensile strength to the construction. |
| Reinforced Concrete | Concrete containing adequate reinforcement (pre-stressed or not prestressed) and designed on the assumption that concrete and steel act together in resisting forces; concrete work into which steel bars have been embedded to impart tensile strength to the |
| Reinforced Concrete Pipe | Factory-made precast piping |
| Reinforced Grouted Masonry | Wall construction consisting of brick or block that is grouted solid throughout its entire height and has both vertical and horizontal reinforcing. |
| Reinforced Hollow Unit Masonry | Wall construction consisting of hollow masonry units in which part of all of the cells are continuously grouted and has both horizontal and vertical reinforcing. |
| Reinforced Masonry | Unit masonry in which reinforcement is embedded in such a manner that the two materials act together in resisting forces. |
| Reinforced Membrane | A roofing or waterproofing membrane reinforced with felts, mats, fabrics or chopped fibers. |
| Reinforced Plastics | Plastics reinforced with glass or carbon fibers. |
| Reinforcement | 1. The action or state of strengthening by additional assistance, material, or support. 2. The action or state of strengthening or increasing by fresh additions. 3. Steel bars or wires embedded in concrete and located in such a manner that the metal and t |
| Reinforcement, Mesh | See Welded Wire Fabric. |
| Reinforcing | 1. The act of making stronger. 2. A structure or member that is used to add strength. 3. Steel rods or metal fabric placed in concrete slabs, beams, or columns to increase their strength. |
| Reinforcing | Steel rods or metal fabric placed in concrete slabs, beams, or columns to increase their strength. |
| Reinforcing Accessory | Items used to install reinforcing in concrete, including, but not limited to, chairs, couplings, and tie wire. |
| Reinforcing Bar | A manufactured, usually deformed, steel bar, used in concrete and masonry construction to resist tensile stresses. |
| Reinforcing, Masonry | See Masonry Reinforcing. |
| REL | Recommended Exposure Limits; recommendations made by NIOSH. |
| Relative Humidity | The ratio of the amount of water vapor actually present in the air to the amount present when the air is saturated with water vapor at the same temperature, expressed as a percentage. |
| Relay | An electromagnetic mechanism, moved by a small electrical current in a control circuit, which operates a valve or switch in an operating circuit. |
| Relay, AC | See AC Relay. |
| Release Agent | Material used to prevent bonding of concrete to a form surface. |
| Release Clause | A provision in a mortgage or trust deed which allows a portion of the encumbered property to be released from the mortgage upon the payment of a specified sum of money to the lender. |
| Reliction | An increase in land area caused by the gradual recession of sea or river water. |
| Relief | 1. Damages or court orders awarded in litigation. 2. Ornamented prominence of parts of figures above a plane surface. |
| Relief Joint | See Control Joint and Expansion Joint. |
| Relief Valve | A pressure safety valve installed on water heaters, hot water and boiler tanks to relieve pressure when it exceeds a preset level. |
| Relief Vent | In a DWV system, a vent coming from a vent stack and connecting to a horizontal branch at a point between the first fixture connection on that branch and the soil stack or waste stack; its purpose is to allow the circulation of air between the vent stack |
| Relief Ventilator | An auxiliary vent whose main purpose is to provide supplementary circulation of air. |
| Relieving Arch | See Discharging Arch. |
| Reline Pipe | To install new linings in pipes; usually includes the cleaning of built-up scale or debris from the existing pipe and relining with a compatible material. |
| Reluctance | A force working against the passage of magnetic lines of force (flux) through a magnetic substance. |
| Remainder | The estate in real property that remains after a life estate terminates upon the death of the holder. |
| Remainderman | The person entitled to the estate that remains after termination of a life estate. |
| Remaining Economic Life | The time period from the present to the point where a real property improvement becomes valueless. |
| Remote | Remote electrical, gas, or water meter digital readouts that are installed near the front of the home in order for utility companies to easily read the home owners usage of the service. |
| Remote Control Circuit | Any electrical circuit which controls any other circuit through a relay or an equivalent device. |
| Remote Power Element Control | Device with sensing element located apart from the operating mechanism it controls. |
| Remote System | Refrigerating system in which condensing unit is away from space to be cooled. |
| Removable Railing Section | Section of a railing designed and constructed to be removed easily to facilitate movement through the railing. |
| Removable Window Well Cover | Removable steel bar or expanded metal cover for a window well. |
| Remove | The act or process of demolishing, dismantling, and carrying away an old fitting or component. |
| Removers | Compositions designed to soften old varnish or paint coats so that they may be easily removed by scraping or washing. |
| Renaissance | 1.Rebirth; revival. 2. The art and architecture developed during the period of 14-17th century; the transition between medieval and modern times, marked by the revival of classical styles and the beginnings of modern science. |
| Renaissance Cities | Formal plans of a symmetric nature; hierarchical articulation of spaces between more prominent and less prominent parts of the cities, such as palaces, monuments, and other focal points. |
| Rendering | 1. An architectural drawing, often in color and in perspective. 2. Application of plaster directly to a masonry wall. |
| Rental Value | A measure of damages for deprivation of the use of property. |
| rep | A ribbed cloth of lightly woven cotton. |
| Repair | The reconstruction or renewal of any part of an existing building for the purpose of its maintenance. |
| Repeat | In carpet, fabric, and wallpaper, the distance from a point in a pattern figure to the same point where it occurs again, measuring lengthwise of the material. |
| Replacement Reserves | A portion of the annual income set aside for replacement of wasting assets, such as roofing, mechanical and electrical equipment, and other impermanent building components. |
| Replevin | A legal process whereby personal property that has been unlawfully taken from one may be recovered. |
| Replication | A copy or reproduction. |
| Reprographics | Systems for reproducing graphic materials, including architectural and engineering drawings and diagrams. |
| Reproofing | The practice of applying new roofing materials over existing roofing materials. |
| Repulsion-Start Induction Motor | An electric motor type which has an electrical winding on the rotor for starting purposes. |
| Required Strength | The strength of a member or cross section required to resist factored loads or related internal moments and forces. |
| Reredos | 1. An ornamental wall behind an altar in a church. 2. The back of a fireplace or open hearth. |
| Res Judicata | The doctrine that courts will not re-litigate the same issues between the same parties. |
| Resawing | Sawing lumber again after the first sawing; specifically, sawing into boards or dimension lumber. |
| Rescission | A legal remedy for a material breach of contract under which the law pretends that a contract never existed and attempts to put the parties in the positions they occupied before the contract was executed; a cancellation. |
| Reserves | Portions of current income set aside and accumulated at interest to pay for future maintenance, repairs, and replacement of equipment. |
| Residence | A building for human habitation; a dwelling. |
| Residential Carpet | A grade or style of carpet installed in low foot-traffic applications. |
| Residential Equipment | An appliance or piece of equipment found in the home, that is used by the homeowner. |
| Residential Occupancy | A building or any portion of a building containing one or more dwelling units. |
| Residual | 1. The remainder or residue after a chemical reaction or a transaction. 2. Free acting disinfectant remaining in poolwater after treating and breaking down pollution. |
| Residual Stress | Stress remaining in a structure or member as a result of thermal or mechanical treatment or both. |
| Residual, Building | See Building Residual. |
| Residual, Land | See Land Residual. |
| Resilience | 1. Ability of a material to resume its original size and shape after deformation, such as stretching, twisting, compression, or indentation. 2. The measurement of the absorption of dynamic energy by a structure without permanent deformation or fracture. 3 |
| Resilient Channel | A metal furring member designed to absorb sound or noise impact which strikes the surfacing membrane. |
| Resilient Floor Covering Institute (RFCI) | 1030 15th Street, NW, Suite 350, Washington, DC 20005, (202) 833-2635. |
| Resilient Flooring | Flooring materials such as asphalt, vinyl, linoleum, rubber, cork, and similar resilient materials; available in tile or sheet form. |
| Resin | A sticky material obtained from the sap of certain trees and plants (natural resin) or made synthetically from coal-tar products and other organic substances (synthetic resin); resins are widely used in making varnishes and paints. |
| Resin Hardness | Method of indicating hardness of resins; usually from No. 1 (hardest) to No. 6. |
| Resist Printing | Placing a dye-resist agent on carpet prior to piece dyeing so that the pile will absorb color according to a predetermined design. |
| Resistance | 1. An opposing or retardant force. 2. An opposition to flow or movement such as friction. 3. The property of hindering the conduction of electricity or heat. |
| Resistance or R-Value | The tendency of a material to retard the flow of heat. |
| Resistivity (r | ). The property of hindering the conduction of heat or electricity; the reciprocal of conductivity, l/k. |
| Resistor | Electrical device having resistance to the passage of electrical current. |
| Resolving Forces | Replacing a force or forces with two or more other forces that yield the same effect on a structure as the original forces. |
| Resonance | Movement produced in an element as a result of movement added to its natural period of movement, which is the same. |
| Resorcinol Glue | A glue that is high in both wet and dry strength and resistant to high temperatures. It is used for gluing lumber or assembly joints that must withstand severe service conditions. |
| Resorcinol Glue | A glue that is high in both wet and dry strength and resistant to high temperatures; used for gluing lumber or assembly joints that must withstand severe service conditions. |
| Respirator | A device for maintaining artificial respiration. |
| Respirator Mask | A device worn over the mouth to aid in breathing. |
| Respondiat Superior | The doctrine that a principal is liable for the acts of an agent, and an employer for the acts of an employee. |
| Response | Effect produced on a structure by earthquake ground motion. |
| Restaurant | A room or building for preparing and serving meals to the public. |
| Restoration | The act of restoring to an original condition; the act or process of bringing a structure back to its former position or condition. |
| Restretch | A term applied to the remedial steps necessary for the correction of improperly laid carpet resulting from application of wrong stretching techniques, carpet defects, or undetermined causes. |
| Restrictor | A device for producing a deliberate pressure drop or resistance in a line by reducing the cross-sectional flow area. |
| Restroom | A room in a public place equipped with toilets, urinals, and lavatories, usually segregated by gender. |
| Resultant | A force that will produce the same effect as two or more combined forces. |
| Retainage | Amount of construction sum held back by the owner from the contractor to be paid after construction is satisfactorily completed; also called Retention. |
| Retained Earnings | The accumulated earnings that are retained in a corporation since it was founded less the total of dividends declared to the stockholders. |
| Retaining wall | A structure that holds back a slope and prevents erosion. |
| Retaining Wall | A wall that is designed to resist the lateral pressures of retained soil; a wall that holds back a hillside or is backfilled to create a level surface. |
| Retardant, Fire | See Fire Retardant. |
| Retardation | Delaying the hardening or strength gain of fresh concrete, mortar or grout. |
| Retarder | 1. A concrete admixture used to slow down the natural curing process. 2. An admixture used to delay the setting action of plaster; generally used only with gypsum plasters or finish coat plaster containing calcined gypsum gauging. 3. Slow drying solvents |
| Retemper | Addition of water to portland cement plaster, mortar, or concrete after mixing but before setting process has started. |
| Retentions | Amounts withheld from progress billings until final and satisfactory project completion. |
| Retrofitting | To install new materials or equipment in an existing building. |
| Return | 1. Any surface turned back from the face of a principal surface. 2. The ending of a small splash wall or a wainscot at right angle to the major wall. 3. The continuation of a molding or finish of any kind in a different direction. 4. In HVAC, a term for t |
| return | The part of a curtain, drapery, cornice, or valance that goes around the side. To hang flush with the wall at right angles, it is usually equivalent to the distance between the front surface and the wall. |
| Return Air Duct | The duct by which air is returned from a room or space to the heating or cooling system to be reconditioned and re-used. |
| Return Lines | Pipework returning water to be recooled or reheated. 2. Pipework returning filtered water to the pool. |
| Return Off-Set | See Jumpover. |
| Return on Investment | The percentage of earnings on the total assets of a corporation. |
| Return Period of Earthquakes | The time period in which the probability that an earthquake of a certain magnitude will reoccur. |
| Return Piping | That part of the piping between the filter and the pool, spa or hot tub through which passes the filtered water. |
| Rev | 1. Revised. 2. Revision. 3. Reverse. 4. Reversed. |
| Reveal | The side of an opening, as a window or door jamb. |
| Revenues | The gross income of a business. |
| Reverberation | The persistence or echoing of previously generated sound caused by reflection of acoustic waves from the surfaces of enclosed spaces; the support of sound by successive reflections. |
| Reverberation Time | The time is takes sound to become inaudible; a function of a space, people, furnishings, and the absorptivity of the surfaces. |
| Reverse Coloring | The changing of yarn frames in Jacquard weaves to cause the interchanging of ground and top colors, according to customers' preferences. |
| Reverse Cycle Defrost | 1. Method of heating evaporator for defrosting purposes. 2. Valves to move hot gas from compressor into evaporator. |
| Reverse Engineering | The study and analysis of a product in order to gain information about its design, construction, and use, for designing a new improved version. |
| Reverse Thrust Fault | A geological fault under compression where the overlying block moves up the dip of the fault plane. |
| Reversible Lock | A lock that will function on doors of either hand, sometimes with slight adjustments. |
| Reversing Valve | Device used to reverse direction of the refrigerant flow depending upon whether heating or cooling is desired. |
| Reversionary Clause | A provision in a deed that provides for the property to revert to the grantor in the event that any of the restrictions are violated. |
| Revetment | A facing of stone, bags, blocks, pavement, etc., used to protect or armor a bank against erosion. |
| Revibration | The delayed vibration of concrete that has already been placed and consolidated; most effective when done at the latest time a running vibrator will sink of its own weight into the concrete and again make it plastic. |
| Revolving Door | Typically a four panel door attached at 90 degrees to each other that turns on a center axis; some are 3 panel attached at 120 degrees to each other. |
| Reynolds Numbers | A numerical ratio of the dynamic forces of mass flow to the shear stress due to viscosity. |
| RF Curing | Radio Frequency curing. |
| RFCI | Resilient Floor Covering Institute. |
| RFP | Request for Proposal. |
| RH 1 | Right hand. 2. Right Hand, a door handing designation. |
| Rheology | A science dealing with the deformation and flow of matter. |
| Rheostat | An electrical instrument used to control a current by varying the resistance. |
| RHMS | Round Head Machine Screw. |
| Rhombus | A polygon with four equal sides that do not meet at right angles. |
| RHR | Right Hand Reverse, a door handing designation. |
| RHWS | Round Head Wood Screw. |
| Rib | 1. A plain or molded arched member which forms a support for an arch or vault. 2. A decorative feature resembling a rib on the surface of a vault or ceiling; a projecting piece of molding upon the interior of a vault or used to form tracery in ornamental |
| Rib Lath | Metal lath with ribs formed by folding to provide stiffness for greater span. |
| Ribband | 1. The support for the second-floor joists of a balloon-frame house.2. The horizontal member of a wood frame wall which supports floor joists or roof rafters; also called a Ribbon. |
| Ribbed Shells | Spatial structures with material placed primarily along certain preferred rib lines, with the area between the ribs filled with thin slabs or left open. |
| Ribbon (girt) | Normally a 1 X 4 board let into the studs horizontally to support the ceiling or second-floor joists. |
| Richter Scale | A logarithmic scale that is used to measure the magnitude of earthquakes. |
| Riddle | A coarse sieve, as for sand or gravel. |
| Ride the Brush | To bear down on the brush to the extent that the paint is applied with the sides of the bristles instead of the flat ends; this shortens the life of the brush. |
| Ridge | 1. The top edge or corner formed by the intersection of two roof surfaces. 2. The board against which the tips of rafters are fastened. |
| Ridge Board | The board against which the tips of rafters are fastened; the top line of a roof; the ridge. |
| Ridge Cut | Any cut made in a vertical plane; the vertical cut at the top end of a rafter. |
| Ridge Rib | A rib forming the ridge in a vaulted roof. |
| Ridge shingles | Shingles used to cover the ridge board. |
| Ridge Vent | A vent mounted along the ridge of a roof to aid in ventilating an attic space. |
| Ridge, Roof | See Roof Ridge. |
| Ridging | 1. An upward, tenting displacement of a roofing membrane, frequently occurring over insulation joints, deck joints, and base sheet edges. 2. See Beading. |
| Riffler | A small handtool for filing, scribing, or scraping. |
| Rifle Range | A place where rifle shooting is practiced. |
| Rift Valley | A graben. |
| Right Angle | An angle of 90 degrees. |
| Right Triangle | A triangle having one right angle. |
| Right-of-Way | The legal right, usually by easement, to pass over land owned by another. |
| Rigid Copper Tubing | Hard copper pipe used when installing water lines, particularly where they can be seen. |
| Rigid Frame | Two columns and a beam or beams attached with moment connections; a moment-resisting building frame; the connections between the beam and columns are constructed so as to transmit moments. |
| Rigid Insulation | Thermal insulating material made of polystyrene, polyurethane, polyisocyanurate, cellular glass, or glass fiber, sometimes offered with a skin surfacing, formed to flat board shape of constant thickness. |
| Rigidity | Relative stiffness of a structure or element. |
| Rill Erosion | Removal of soil particles from a bank slope by surface runoff moving through relatively small channels. |
| Rim | A designation of articles of hardware designed for application to the surface of doors and windows, such as rim locks. |
| Rim joist | A joist that runs around the perimeter of the floor joists and home. |
| Ring Nail | See Annular Ring Nail. |
| Ring, Split | See Split Ring. |
| Ring, Toothed | See Toothed Ring. |
| Ringelmann Sale | Device for measuring smoke density. |
| Rip | To cut lumber lengthwise, parallel to the grain. |
| Rip Fence | A guide on a table saw to assist in cutting lumber in the direction parallel to the grain. |
| Riparian Rights | The rights of an owner whose land adjoins water, such as a river, stream, lake, or sea. |
| Ripper | Narrow strips of gypsum board used for soffits, window returns and finished openings. |
| Ripping | Sawing wood along the grain. |
| Ripple Effect | The effect that escalation or delay has on other work in a construction schedule; impact. |
| Riprap | A layer, facing, or protective mound of stones, randomly placed to prevent erosion or scour at a structure or embankment,- also the stone so used. |
| Ripsaw | A saw designed for cutting lumber length wise. |
| RIS | Redwood Inspection Service. |
| Rise | The vertical distance through which anything rises, as the rise of a roof or stair. |
| Riser | 1. A single vertical increment of a stair; the vertical face between two treads in a stair. 2. A vertical run of plumbing, wiring or ductwork. 3. A spacer between shipping units to allow entry of fork lift blades. 4. The flow channel or pipe that distribu |
| Riser and panel | The exterior vertical pipe (riser) and metal electric box (panel) the electrician provides and installs at the "Rough Electric" stage. |
| Riser Band | A flat, horizontal member usually ornamental, of relatively slight projection, mounted on a riser between two stair treads. |
| Riser Hanger | The horizontal member of a stair structure which supports the riser. |
| Riser Valve | Device used to manually control flow of refrigerant in vertical piping. |
| Risk | Chance or possibility of danger, loss, injury, or other adverse consequences. |
| Risk Management | The taking of precautions to avoid unexpected property and casualty losses which can severely damage the business's prospects; insurance is one of the best means of reducing the company's exposure to risk. |
| River training works | Structures placed in a stream to direct the current into a predetermined channel. |
| Rivet | A structural fastener on which a second head is formed after the fastener is in place. |
| Rivet Pattern | The arrangement, spacings, and dimensions of rivets used to attach two or more structural members together. |
| Riviera Blind | 1" aluminum blind made by Levolor |
| Riviera Contract | 1" blind 6 gauge contract aluminum miniblind made by Levolor |
| RMA | Rubber Manufacturers Association. |
| Ro | Rough. |
| Road base | A aggregate mixture of sand and stone. |
| Road Oil | A heavy petroleum oil, usually one of the Slow-Curing (SC) grades. |
| Roadway Excavation | The act or process of removing or moving obstructions such as boulders, rocks, earth to prepare a path for a road or highway. |
| Robert Allen | Fabric vendor with huge assortment. Broad price range. (55 Cabot Blvd., Mansfield, MA 02048) |
| Robot | A mechanical device that is operated by automatic controls and is used in manufacturing processes to perform functions previously carried out by human workers. |
| Robotics | The science concerned with the design, manufacture, and utilization of robots. |
| Rocaille | Ornamental style of 18th century with stylized pebbles, shell shapes and scrolls typical of Rococo decoration. |
| Rock | Soil particles greater than 3 inches in diameter. |
| Rock | The hard, firm, and stable parts of earth's crust; any material which requires blasting before it can be dug by available equipment. |
| Rock 1, 2, 3 | When referring to drywall, this means to install drywall to the walls and ceilings (with nails and screws), and before taping is performed. |
| Rock Anchor | A post-tensioned rod or cable inserted into a rock formation for the purpose of anchoring a structure to it. |
| Rock Asphalt | See Asphalt Rock. |
| Rock Drilling | The act or process of boring holes into rock. |
| Rock Flour | Crushed rock in fine particles like powder. |
| Rock Gun | A device for throwing aggregate onto a soft bedding coat in applying marblecrete. |
| Rock Pocket | A concrete defect in which a group of aggregate is not adequately surrounded by cement paste |
| Rockwool Insulation | Insulation made by forming fibers from molten rock and slag; used as insulation in ceilings and walls. |
| Rococo | An artistic style of the 18th century that is characterized by fanciful, excessive, intricate, and elaborate ornamentation; baroque. |
| Rod | 1. A slender stick, pole, or bar of wood or metal. 2. A unit of length, used in land measuring, of 16.5 feet. 3. A square rod, 273.9 square feet. |
| rod | A rail or track from which a curtain, drapery, or sometimes a valance is hung. A traverse rod is operated with a cord and pulley system, and curtains on a flat curtain rod are opened and closed by hand. |
| Rod Saw | A saw consisting of a steel rod approximately 1/8" in diameter used to cut circles or irregular curves in tile; the rod has tungsten carbide particles embedded in the surface. |
| Rod, Ground | See Ground Rod. |
| Rod, Guy | See Guy Rod. |
| Rod, Hanger | See Hanger Rod. |
| Rod, Tamping | See Tamping Rod. |
| Rod, Traverse | See Traverse Rod. |
| rod-pocket curtain | A curtain where the top forms a pocket which is gathered onto a rod or pole. |
| Rodding Off | See Floating. |
| Roll Roof | A roof that has been covered with an asphaltic material that comes in rolls. |
| Roll Roofing | Asphaltic roofing, coated felts, either smooth or mineral surfaced, that comes in rolls; |
| Roll, rolling | To install the floor joists or trusses in their correct place. (To "roll the floor" means to install the floor joists). |
| Roll-Up Door | A door which raises and rolls into a coiled configuration and lowers on tracks on either jamb. |
| Rolled | A brick that is laid with an overhanging face. |
| Rolled Steel Section | Any hot-rolled steel member such as a wide flange beam, I-beam, angle, channel, tee, or similar sections. |
| Roller Blind | A window covering that retracts to the top of the window by means of a spring-loaded roller. |
| Roller Coating | 1. A paint or other material applied to the surface by a paint roller. 2. Process of finishing an article by means of hard rubber or steel rollers. |
| Roller Latch | A friction door latch employing a roller under spring tension which engages a recessed strike plate formed to receive the roller. |
| Roller Marks | Surface defects caused during the manufacturing process as the gypsum board is moved through the various production operations. |
| Roller Shade | A window shade on spring-loaded a roller that allows the shade to go up and down. |
| Roller Strike | A door latch strike having a rolling member at the point of latch bolt contact to minimize friction. |
| Rolok Wall | An economy wall and a substitute for a solid brick wall, it is a combination of several shells of brickwork laid flat or on edge to produce a cellular type of open construction. |
| ROM | Read Only Memory. |
| Roman Arch | A round topped arch. |
| Roman Brick | Brick whose nominal dimensions are 3-1/2 x 2 x 12 inches. |
| Roman Cities | Influenced by the plan used for military camps, grid iron city blocks; more formal organization of public spaces in the nucleus of city. |
| Roman Numeral | 1. Any of the Roman letters representing numbers, I = 1, V = 5, X = 10, L = 50, D = 500, M = 1000. 2. A numeral in the system of notation that is based on the ancient Roman system. |
| Roman shade | A flat shade with dowels slotted horizontally up the back, so it can easily be pulled up into soft horizontal folds. |
| Romanesque | A style of architecture prevalent in Europe in the 9-12th century, with massive vaulting, round arches, decorative use of arcades, and profuse ornament. |
| Romex | A name brand of nonmetallic sheathed electrical cable that is used for indoor wiring. |
| Rood Screen | A decorative screen separating the nave from the chancel. |
| Roof | 1. The top cover of a building or structure. 2. The top limit on price, a Ceiling Price. |
| Roof Adhesive | A bonding agent used to cement roof materials. |
| Roof Assembly | An assembly of interacting roof components, including the roof deck, designed to weatherproof and, normally, to insulate a building's top surface. |
| Roof Ballast | Crushed rock or gravel which is spread on a roof surface to form its final surface. |
| Roof Bond | A legal guarantee that a roof installed is in accordance with specifications and will be repaired or replaced if it fails within a certain period of time due to normal weathering. |
| Roof Cricket | Relatively small elevated area of wood roof constructed to divert water around chimney, curb, or other projection. |
| Roof Decking | 1. Two inch or thicker lumber installed on a roof system. 2. The structural skin of a roof. |
| Roof Drain | 1. A drainage outlet on a roof. 2. A drainage conduit or pipe that collects water runoff from a roof and leads it away from the structure. |
| Roof Expansion Joint | A break or space between roofing materials to allow for thermal expansion and contraction. |
| Roof Flashing | A weather shield commonly used at penetrations of a roof by pipes or columns to insure no passage of the elements. |
| Roof Framing | The skeleton structure of a roof system. |
| Roof Hatch | Fabricated, usually of metal, horizontal access door mounted on curb to permit access to flat or low sloped roofs from the building interior. |
| Roof Insulation | 1. Materials used between rafters or roof supports for the protection from heat and cold. 2. Solid sheets of insulating material installed on a flat roof. |
| Roof jack | Sleeves that fit around the black plumbing waste vent pipes at, and are nailed to, the roof sheeting. |
| Roof joist | The rafters of a flat roof. Lumber used to support the roof sheeting and roof loads. Generally, 2 X 10's and 2 X 12's are used. |
| Roof Panel | Roof panel construction from boards, plywood, or metal sheets that can be installed as a pre-assembled unit. |
| Roof Ridge | The uppermost peak of a roof where the roof planes meet. |
| Roof Scupper | See Scupper, 1. |
| Roof sheathing | The boards or sheet material fastened to the roof rafters on which the shingle or other roof covering is laid. |
| Roof sheathing or sheeting | The wood panels or sheet material fastened to the roof rafters or trusses on which the shingle or other roof covering is laid. |
| Roof Shingle | Pieces of wedge shaped wood or other material used in overlapping courses to cover a roof, usually made of wood, asphalt, clay tile, or metal. |
| Roof Slab | The flat section of a reinforced concrete roof, supported by beams, columns, or other framework. |
| Roof Specialties | A fitting or piece of trim used in the installation of a roof, such as gravel stop, flashing, or vent strips. |
| Roof Spinner | An exhaust ventilation apparatus mounted on a roof which uses the wind to create an upward draft and thus create ventilation. |
| Roof System | A general term for the complete assembly of waterproof covering, insulation, vapor barrier, ballast, and substrate. |
| Roof valley | The "V" created where two sloping roofs meet. |
| Roof Vent | 1. A usually screened opening on a gable end or roof structure to allow a free flow of ventilation air into the underroof area. 2. The unit mounted on a roof that is the terminus of a ventilation pipe. |
| Roof Walkway | A permanent aisle for safe access across a roof, also serves as a protection for the roofing material when maintenance is being done. |
| Roof, Asphalt | See Asphalt Roof. |
| Roof, Built-Up | See Built-Up Roof |
| Roof, Curb | See Gambrel Roof. |
| Roof, Fluid-Applied | See Fluid-Applied Roof. |
| Roof, Hip | See Hip Roof. |
| Roofer | A person who constructs or repairs roofs. |
| Roofing | 1. Materials for a roof. 2. The process of constructing a roof. 3. The skilled trade of applying roofing; a Roofer. |
| Roofing Cement | A general term for a variety of trowelable mastics, asphalt, or tar that are used in roof construction and repair. |
| Roofing Consultant | An expert in the design, specification, construction, and repair of roofs. |
| Roofing Felt | A felt sheet impregnated with a bituminous waterproofing material. |
| Roofing Nail | A short, often galvanized, nail with a broad head. |
| Roofing Removal | The act or process of stripping off an old roof system. |
| Roofing Square | 1. An area of 10 by 10 feet of roofing surface. 2. 100 square feet of roofing surface. |
| Roofing System | A group of interacting roof parts designed to weatherproof and to insulate a roof. |
| Rooftop AC | Air-conditioning system or equipment installed on a roof. |
| Rooftop Heater | A heating unit installed or placed on a roof. |
| Rooftop Unit | A system of conditioning air in a self contained unit, installed directly above the conditioned space, in a weatherproof enclosure. |
| Room Resonance | The sound resonance of an enclosed space, which depends in the relationship between the sound wavelength, the space dimensions, and the reflective surfaces. |
| Rooming House | A hotel. |
| Root Ball | The soil and earth that clings to roots of a dug up tree that is later to be planted in a different location. |
| Root Buttress | A root that is above ground where it joins the trunk of a tree. |
| Root Face | In welding, that portion of the groove face adjacent to the root of the joint. |
| Root Hook | A very heavy hook designed to catch and tear out big roots when it is dragged along the ground. |
| Root of Joint | That portion of a joint to be welded where the members are closest to each other. |
| Root of Weld | The point at which the bottom of the weld intersects the base-metal surfaces and is the farthest from application of weld heat and/or filler metal side. |
| Root Opening | In welding, the separation between the members to be joined at the root of the joint. |
| Rooted | Expression indicating that a bank has been excavated and the end of a structure (check dam, dike, etc.) has been placed in the cavity, thus retarding future streamflow around the end of the structure (flanking). |
| Rope | A stout cord made by twisting or braiding together strands of hemp, sisal, flax, cotton, nylon, wire, or similar material. |
| Rose | A trim plate attached to the door hardware behind the knob. |
| Rose-Window | A round window filled with tracery and, usually, stained glass; characteristic of Gothic churches. |
| Rosette | 1. A circular decorative ornament made of wood, metal, or plaster. 2. A metal trim at a ceiling mounted lighting fixture or at a blanked-off lighting fixture outlet. |
| Rosewood Veneer | A thin layer of cabinet wood with a dark red or purplish color streaked and variegated with black, applied to give a superior and decorative surface. |
| Rosin | A hard resin obtained from pine trees containing principally isomers of abietic acid; wood rosin is obtained from stump or dead wood, using steam distillation; gum rosin is obtained from the living treerosin is used in making varnish, soap, and solder flu |
| Rot | Decay. |
| Rotary Blade Compressor | Mechanism for pumping fluid by revolving blades inside a cylindrical housing. |
| Rotary Compressor | See Compressor, Rotary. |
| Rotary-Cut Veneer | Veneer cut in a lathe which rotates a log or bolt, chucked in the center, against a knife. |
| Rotate | To turn or revolve about an axis or center. |
| Rotation | In building structures, the torsional movement of a diaphragm about a vertical axis. |
| Rotisserie | 1. A restaurant specializing in roasted and barbecued meats. 2. A cooking device with a revolving spit for roasting and barbecuing meat. |
| Rotor | A rotary part of a machine. |
| Rottenstone | A siliceous limestone which when finely pulverized, is used in wood finishing; it has negligible cutting action but is fine for polishing; also called Tripoli. |
| Rough Horse | See Carriage. |
| Rough Lumber | Lumber that has not been dressed (surfaced) but which has been sawed, edged , and trimmed. |
| Rough Opening | The clear dimensions of the framed opening that must be provided in a wall to accept a given door, window unit, or other unit. |
| Rough sill | The framing member at the bottom of a rough opening for a window. It is attached to the cripple studs below the rough opening. |
| Rough- | In. All work that must be performed before plastering. |
| Roughing-in | The initial stage of a plumbing, electrical, heating, carpentry, and/or other project, when all components that won't be seen after the second finishing phase are assembled. See also Heat Rough, Plumbing Rough, and Electrical Rough. |
| Round | 1. Circular. 2. A wooden dowel. |
| Round Edge | A preformed factory rounded edge design. |
| Round Head Wood Screw (RHWS) | A wood screw with a rounded head protruding above the surface; driven with a screw driver; usually installed with a washer under the head. |
| Round Pattern | Circular spray pattern. |
| Round Wire | See Loop Pile. |
| Round, Quarter | See Quarter Round. |
| Rout | To gouge out or make a furrow in, as in wood. |
| Router | Woodworking tool with a high speed bit for cutting rebates, dadoes, insetting butts, and forming decorative or rounded edges. |
| Row House | One of a series of houses connected by common sidewalls and forming a continuous group. |
| Rowlock Course | A course of headers laid on their edges instead of flat side; rows of brick laid on edge especially used for the ring of an arch. |
| Rows | The number of lengthwise yarn tufts in one inch of Axminster or Chenille carpet; compare with Wires. |
| RPM | Revolutions Per Minute. |
| RTU | Roof Top Unit. |
| Rub Joint | A glue joint made by carefully fitting the edges together, spreading glue between them, and rubbing the pieces back and forth until the pieces are well rubbed together. |
| Rubber | A tough elastic material made from the latex of rubber trees, a natural polymer of a hydrocarbon. |
| Rubber Emulsion Paint | Paint with a vehicle of fine droplets of natural or synthetic rubber dispersed in water. |
| Rubber Manufacturers Association (RMA) | 1400 K Street, NW, Washington, DC 20005, (202) 682-4800 |
| Rubber Nosing | The projection of a rubberized stair tread over a riser in a stair system. |
| Rubber Set | See False Set. |
| Rubber Spacers | Cross and tee-shaped objects used to space tile on floors or walls; manufactured in thicknesses of 1/16", 1/8", 1/4", 3/8", and 1/2". |
| Rubber Trowel | A non-porous synthetic-rubber-faced float mounted on an aluminum back with a wood handle, used in tile grouting to force material deep into tile joints and to remove excess grout. |
| Rubber, Laminated | See Laminated Rubber. |
| Rubber-emulsion paint | Paint, the vehicle of which consists of rubber or synthetic rubber dispersed in fine droplets in water. |
| Rubbing Compound | An abrasive material used to produce a smooth finished wood surface. |
| Rubbing Oil | Neutral, medium-heavy mineral oil used as a lubricant for pumice stone in rubbing varnish and lacquer. |
| Rubbing Stone | A carborundum stone that is used to smooth the rough edges of tile. |
| Rubbing Varnish | A hard-drying varnish which may be rubbed with an abrasive and water or oil to a uniform leveled surface. |
| Rubbish Handling | The act or process of transporting or removing waste materials. |
| Rubbish Removal | The process of removing waste or garbage from an area. |
| Rubble | 1. Roughly broken quarry stone. 2. Rough broken stones or bricks used to fill in courses of walls or for other filling; |
| Rubble | Rough, irregular fragments of rock or concrete. Runup The rush of water up a beach or structure, associated with the breaking of a wave. The amount of runup is measured according to the vertical height above still water level that the rush of water reache |
| Rubble Masonry | Uncut stone, used for rough work, foundations, backfilling, and the like. |
| Rug | A term used to designate soft floor coverings laid on the floor but not fastened to it; usually a rug does not cover the entire floor. |
| Rule-of-Thumb | A rule for general guidance based on experience rather than on precision or scientific theory. |
| Ruler | A straight, usually graduated, piece of wood, plastic, or metal, used for drawing straight lines or for measuring. |
| Run | 1. In a stairway, the width of a step, measured from the face of one riser to the face of the next, and not including the nosing. 2. The horizontal distance covered by a flight of steps. 3. The length of the horizontal projection of a sloping member such |
| Run, roof | The horizontal distance from the eaves to a point directly under the ridge. One half the span. |
| Run, stair | The horizontal distance of a stair tread from the nose to the riser. |
| Rung | A step on a ladder. |
| Runner | Metal or wood track or strips placed at floor and ceiling to receive framing members, such as metal or wood studs. |
| Runner Channel | A steel channel member from which furring channels and lath are supported in a suspended plaster ceiling. |
| Running Bond | Brickwork consisting entirely of stretchers, lapping of units in successive courses so that the vertical head joints lap. |
| Running Mold | Constructed by plasterers in place by use of a metal pattern to form a molding of fresh plaster. |
| Running Time | Amount of time a condensing unit is run per hour or per 24 hours. |
| Running Track | An oval-shaped track for use by athletes in various running events. |
| Running Trap | A plumbing trap in which the inlet and outlet are in a straight horizontal line between which the water way is depressed to below the bottom of either the inlet or outlet. |
| Running Winding | Electrical winding of motor which has current flowing through it during normal operation of motor. |
| Runoff | The excess of rainwater or snowmelt that is not absorbed into the earth and drains to streams, rivers, or storm water collection devices. |
| Runs | In painting, curtains, sags, and other irregularities due to uneven flow. |
| Rural Letter Box | A roadside receptacle usually found in rural areas for delivery of mail. |
| Rust | A reddish or yellowish-brown coating formed on iron or steel caused by oxidation, usually as a result of moisture; ferrous oxide. |
| Rust-Inhibitive Washes | Solutions which etch the metal and form a dull gray coating of uniformly fine texture, thus producing rust-inhibitive surface receptive to priming coat. |
| Rusticated Concrete | Beveled edges of concrete making the joints conspicuous. |
| Rustification | In building and masonry, the use of squared or hewn stone blocks with roughened surfaces and edges deeply beveled or grooved to make the joints conspicuous. |
| Rutile | A mineral form of titanium oxide, TiO2, tetragonal crystallization, but usually produced chemically for use in ceramics and other products. |
| RW | Redwood. |
| Rwd | Redwood. |