R

rabbet, rebate 1. A longitudinal channel, groove, or recess cut out of the edge or face of a member; esp. one to receive another member, or one to receive a frame inserted in a door or window opening, or the recess into which glass is installed in a window sash. 2. A rabbet joint. 3. A shallow recess in one body to receive another, as at the edges of a pair of doors or windows so shaped as to provide a tight fit; one half of the edge projects beyond, and serves as a stop for, the other edge of each leaf. 4. A rabbet plane.

rabbet bead A bead in the reentrant angle of a rabbet.

rabbet depth In glazing, the depth of the glazing rabbet; equal to the sum of the bite and the edge clearance.

rabbeted doorjamb, rabbeted frame A doorjamb with a rabbet, 3, to receive a door.

rabbeted lock, rebated lock A lock or latch in which the face is flush with the rabbet on a rabbeted doorjamb.

rabbeted siding Same as drop siding.

rabbeted stop A stop, 1 which is integral with a door or window frame.

rabbet joint An edge joint formed by fitting together rabbeted boards or timbers.

rabbet plane A plane, 1 for cutting a groove along the edge of a board; open on one side and having the plane iron (which does the cutting) extend to the open side.

rabbet size In glazing, the actual size of the rabbeted glass opening; equal to the glass size plus two edge clearances.

raceway Any channel designed to enclose and loosely hold electric conductors; may be of metal or of an insulating material; various types include rigid conduit, flexible metallic conduit, nonmetallic conduit, metallic tubing, under-floor raceways, cellular floor raceways, surface metal raceways, structural raceways, wireways and busways, and auxiliary gutters or moldings.

raceway cable distribution system A system for distributing cable in an open or closed metal tray that is suspended within a false ceiling from the structural floor above; generally used in large buildings where complex cable distribution systems require special support.

rack-and-pinion elevator An elevator having electrically driven rotating gear pinions mounted on the car; rotation of the gear pinions moves the car up or down on a stationary gear rack which is mounted vertically in the hoistway.

racked Descriptive of timbering which is braced, providing additional support to prevent deformation.

racking 1. The distortion or movement of a frame. 2. The out-of-plumbness of a structure, or any of its components, that are a result of seismic stress or wind acting on the structure; may also result from thermal expansion and contraction.

racking back The stepping back of courses of brick during the construction phase of a wall, usually in expectation of the wall’s completion at a later date.

racking load A load applied in the plane of an assembly in such manner as to lengthen one diagonal and shorten the other.

rack saw A saw having wide teeth.

rad Abbr. for radiator.

rad and dab Same as wattle and daub.

radial arch Same as segmental arch.

radial arch roof A roof supported by a system of arches radiating from a central point.

radial-arm saw, radial saw A circular saw which is suspended from, and moves along, a cantilevered arm, mounted above the saw table; the blade can be set at any angle (or tilted) with respect to the work.

radial bar Same as radius rod, 2.

radial-blade fan A heavy-duty industrial fan used for severe service, e.g., where foreign material (such as wood chips) passes directly through the fan.

radial brick, radius brick An arch brick, 1.

radial-cut See quarter-cut.

radial grating Nonrectangular grating, in which the bearing bars extend radially from a common center and the cross bars have a pattern of concentric circles.

radially-cut grating Rectangular grating that is cut into panels shaped as annular segments, for use in circular or annular areas.

radial road One of a group of roads which radiate outward from the center of a city, as spokes on a wheel.

radial saw See radial-arm saw.

radial shrinkage The shrinkage of wood across the growth rings during drying; the loss in dimension along the radius of a log.

radial step Same as winder.

radiance The rate of radiant emission per unit solid angle and per unit projected area of a source in a stated angular direction from the surface.

radiant glass Glass containing radiant heating elements.

radiant heating Heating which results from heat transmitted by radiation, as contrasted with heat transmitted by conduction or convection.

radiant heating system A system for heating a room or space by means of heated surfaces (such as panels heated by the flow of hot water or electric current) which provide heat primarily by radiation.

radiant panel test An ASTM standard method of test for the surface flammability of a material, using a radiant heat source.

radiating brick An arch brick, 1.

radiating chapels Chapels projecting radially from the curve of an ambulatory or rarely of an apse.

radiation The transmission of heat through space by means of electromagnetic waves; the heat energy passes through the air between the source and the heated body without heating the intervening air appreciably.

radiation-retarding door See lead-lined door.

radiation-retarding frame See lead-lined frame.

radiation-shielding concrete High-density concrete suitable for enclosing nuclear installations; its aggregate has a high specific gravity; contains a high proportion of atoms having a high atomic weight or consisting of minerals and synthetic glasses of substantial boron content. Also see heavyweight aggregate, boron-loaded concrete.

radiation-shielding door See lead-lined door.

radiator A heating unit usually exposed to view within the room or space to be heated; transfers heat by radiation to objects within visible range, and by conduction to the surrounding air, which in turn is circulated by natural convection; usually fed by steam or hot water.

radius brick See arch brick, 1.

radius diffusion The horizontal axial distance an airstream travels after leaving an air outlet before the maximum stream velocity is reduced to a specified terminal value.

radius gauge See fillet gauge.

radius of gyration In mechanics, the distance from the axis to a point such that, if the whole mass of a body were concentrated at it, the moment of inertia would remain unchanged.

radius rod 1. A plastering tool; a wooden arm fixed at one end to a mold and attached at the other end to a center about which it swivels; a gig stick. 2. A long wooden arm with a marker at one end for tracing large curves.

radius shoe A zinc plate attached to one side of a plasterer’s radius rod at midpoint.

radius tool A radius rod.

radius wall A curved wall that is a segment of a circle.

radon A gaseous emanation produced by the radioactive decay of radium, given off by some soils and rocks; it may collect and constitute a health hazard in buildings with poor ventilation.

rafter One of a series of inclined structural members from the ridge of the roof down to the eaves, providing support for the covering of a roof. For special types of rafters, see beveled rafter, binding rafter, common rafter, compass rafter, compound rafter, fly rafter, hip rafter, jack rafter, knee rafter, notched rafter, principal rafter, valley rafter.

rafter fill Same as beam fill.

rafter house In the Chesapeake Bay area of colonial America, a house of a relatively temporary nature, in which the lower ends of the roof rafters rested directly on the ground; a forerunner of the modern A-frame house.

rafter lookout See lookout, 1.

rafter plate A plate, 2 which supports the lower end of rafters and to which they are fixed.

rafter roof A double roof structure that usually has no purlins; if present, they act merely as stiffeners.

rafter table A table of values, usually on a steel square, used by carpenters to determine the lengths and angles of cut for rafters for a roof.

rafter tail The part of a rafter which overhangs the wall.

raft footing See floating foundation.

raft foundation Same as floating foundation.

rag A large roofing slate that has one edge untrimmed.

rag bolt Same as lewis bolt.

rag felt An asphaltic felt fabricated from the fibers of rags; used for roofing paper and shingles.

raggle, reglet, raglin 1. A manufactured unit, often of terra-cotta, having a groove to receive flashing; also called a raggle block or flashing block. 2. A groove cut in stone or brickwork to receive flashing.

raggle block See raggle, 1.

rag joint Same as rubbed joint.

raglet A raggle.

raglin A raggle.

rag-rolled finish A decorative effect on a painted surface; made by rolling a piece of twisted rag over a coat of wet paint so as to remove portions of it and show the color of the base coat. A similar effect can be achieved with a special paint roller.

rag rubble A type of rubblework composed of thin small stones.

ragstone 1. A rough, shelly, sandy limestone with layers of marl and sandstone. 2. In masonry, stone quarried in thin blocks or slabs.

ragwork 1. Crude masonry, laid in a random pattern of thin-bedded, undressed stone, such as flagging; most commonly set horizontally. 2. Polygonal rubble, set on edge, that serves as an exterior facing.

rail 1. A bar of wood or other material passing from one post or other support to another; a hand support along a stairway. 2. A structure consisting of rails and their sustaining posts, balusters, or pillars, and constituting an enclosure or a line of division, as a balcony rail. 3. A horizontal piece in a frame or paneling as a door rail, or in the framework of a window sash.

rail bead A cock bead when on a uniform continuous surface, and not at an angle, reveal, or the like.

rail bolt A handrail bolt.

rail fence A fence in which the rails are set into the posts; adjoining rails either butt against each other or overlap. Also called a zigzag fence.

railing 1. Rails, collectively, or a combination of rails. 2. Any openwork construction or rail used as a barrier or the like.

rail pile A pile fabricated from railroad rails which are welded together and driven as a unit.

railroad flat A narrow apartment whose rooms are in a straight line; one must pass through each room to get to the next one because there is no internal corridor. Only the front and rear rooms have windows; air shafts along one or both sides of the apartment provide ventilation and a little light in the interior rooms. Primarily constructed on the east coast of America in the 1880s; also called a dumbbell tenement.

rail steel reinforcement Steel reinforcing bars that have been hot-rolled from standard T-section rails.

rainbow roof 1. Same as compass roof. 2. Same as ship’s bottom roof.

rain cap A device which is installed at the upper termination of a chute or vent, above the roof of a building, to prevent rain from entering the interior of the chute; often includes a screen to prevent the entry of birds.

raindrop figure A mottled figure in wood veneer; resembles a raindrop pattern.

rain leader See downspout.

rainproof Constructed, protected, and/or treated to prevent rain from interfering with the successful operation of apparatus.

raintight Constructed, protected, and/or treated so that exposure to intense rainfall will not result in the entrance of water.

rainwater conductor Same as downspout.

rainwater conductor head, rainwater hopper head Same as leader head.

rainwater head See leader head.

rainwater hopper A hopper-shaped leader head.

rainwater pipe A downspout.

rainwater shoe At the foot of a downspout, a short fitting with a bend to discharge the rainwater clear of the building.

raised barn Occasionally, a synonym for a bank barn.

raised basement A basement whose floor level is much higher than usual, so that its ceiling is well above (usually one story above) ground level.

raised cottage 1. Cottage on stilts or built-up piers to protect it from groundwater. 2. Same as raised house.

raised floor A floor fabricated entirely of square plates that rest on interlocked pedestals attached to the structural floor of a building. The plates usually are fabricated of aluminum and are covered with cork, carpet, or vinyl tiles. The plates can be removed to provide convenient access to the cables beneath; used extensively in computer rooms.

raised flooring system A system of flooring consisting of completely removable and interchangeable floor panels which are supported on adjustable pedestals and/or stringers to allow free access to the area beneath.

raised girt, flush girt, raised girth A girt which is parallel to the floor joists and level with them.

raised grain 1. In dressed softwood lumber, surfaces in which the hard summerwood is raised above the soft springwood. 2. In hardwoods, fibers protruding above the normal surface; usually caused by wetting.

raised house In the American South, a house or cottage having a raised basement; this cellar, whose floor is at ground level, often functions as a service area, shop, office, or stable. The main floor (one story above) contains the family living quarters. The exterior walls typically are whitewashed brick, stone, plaster, or stucco. A porch (galerie), extends across the entire façade and sometimes along both sides as well; French doors opening onto the porch promote the flow of air during very hot weather. Also see plantation house.

raised joint Same as excess joint.

raised molding Same as bolection molding.

raised panel, fielded panel A panel with the center portion thicker than the edges or projecting above the surrounding frame or wall surface. When exposed on both sides (as on both sides of a door), it is called a double raised panel.

raised porch In French Vernacular architecture of Louisiana in the 18th century, the galerie of a raised house.

raised table A flat horizontal raised surface which is large in area compared to its elevation above its surroundings.

raising See lifting.

raising bee See barn raising.

raising hammer A hammer with a long head and a rounded face, used in lifting sheet metal.

raising piece A piece of timber laid on a brick wall, or on the top of posts or puncheons of a timber-framed house, to carry a beam or beams; a template.

raising plate A horizontal timber resting on a wall, or upon vertical timbers of a frame, and supporting the heels of rafters or other framework; also called a wall plate.

rajones The term for shingles in Spanish Colonial architecture in the American Southwest.

rake 1. A slope; an inclination; e.g., the inclination (from the horizontal) of an auditorium floor. 2. A board or molding along the sloping edge of a gable; covers the edges of the siding. 3. On the roof of an early colonial house, a flat board covering the lower ends of the rafters.

raked Said of any surface that is inclined with respect to the horizontal, such as a raked molding, or the inclined surface of a raked cornice in a triangular pediment.

rake dimension Same as pitch dimension.

raked joint A joint made by removing the surface of mortar, while it is still soft, with a square-edged tool; is difficult to make watertight; produces marked shadows and tends to darken the overall appearance of a wall.

raked molding Same as raking molding.

rake-out, raking out In masonry, preparing mortar joints for pointing.

raker 1. A tool for raking out decayed mortar from the joints of brickwork, preparatory to repointing them. 2. Any inclined member, as a brace, or pile. 3. A raking shore.

raker pile Same as batter pile.

raking Inclining; having a rake or inclination.

raking arch Same as rampant arch.

raking back Same as racking.

raking bond A method of bricklaying in which the bricks are laid at an angle in the face of the wall; either diagonal bond or herringbone bond.

raking coping A coping set on an inclined surface, as at a gable end.

raking corbel table A corbel table on a slant.

raking cornice A cornice following the slope of a gable, pediment, or roof.

raking course A course of bricks laid diagonally between face courses of a thick wall to strengthen it.

raking flashing A flashing, parallel to the roof slope, which is used to cover the intersection of a chimney and a sloping roof.

raking molding, raked molding 1. Any molding adjusted at a slant, rake, or ramp. 2. Any overhanging molding which has a rake or slope downward and outward.

raking-out In brickwork, preparing mortar joints for pointing.

raking pile A pile that is not driven vertically; a batter pile.

raking riser On stairs, a riser, 1 which is not perpendicular to the tread, but inclined inward to permit more footroom on the tread below.

raking shore, inclined shore An inclined member which supports a wall; a raker, 3.

raking stretcher bond Similar to stretcher bond, except that each stretcher is displaced with respect to the one below, so that it overlaps it by a quarter of a brick rather than a half brick.

raking strut A strut that has an inclination with respect to the horizontal; especially used in pairs between principal rafters and tie beams.

ramada 1. In Spanish architecture and derivatives, a rustic arbor or similar structure. 2. An open porch.

rambler A one-story dwelling; a ranch house.

rammed earth A material usually consisting of clay, sand, or other aggregate (such as sea shells) and water, which has been compressed and dried; used in building construction.

rammer A power-driven tool used to compact soil or other granular material.

ramp 1. A sloped surface connecting two or more planes at different levels. 2. A concave sweep in a vertical plane. 3. The paved area of an airport between the terminal building and the taxiways, used to park airplanes during loading and unloading. 4. According to the Americans with Disabilities Act, a walking surface whose running slope is less steep than 1-in-20.

ramp and twist Any surface that rises and twists simultaneously.

rampant arch, raking arch An arch in which the impost on one side is higher than that on the other. (See illustration p. 796.)

rampant vault A continuous wagon vault, or a cradle vault, whose two abutments are located on an inclined plane, such as a vault supporting or forming the ceiling of a stairway.

rampart An elevated earthen wall for purposes of defense, located on the inner side of a ditch surrounding a bastioned fort.

rampart-walk Same as walk-walk.

ramped step A step with a sloping tread.

ramped steps See stepped ramp.

ramping vault Same as rampant vault.

ram’s-horn figure A curly, wavy figure in wood veneer, like fiddleback.

rance A shore.

ranch house A rambling one-story house, especially popular in the mid-20th century; usually designed to emphasize the horizontal aspects of the house. Typically characterized by: an asymmetrical plan; exterior wall cladding of stucco, brick, wood, or some combination thereof; a low-pitched roof with eaves having a moderate-to-wide overhang, a hipped, cross-gabled, or side-gabled roof; exposed rafters; ribbon windows, windows decorated with shutters; frequently, glass sliding doors that open onto a porch or patio at the side or rear of the house; an attached garage.

ranch-type shingle A rectangular (usually asbestos-cement) shingle which is lapped at the top and on the side.

rand (Brit.) A border, or a fillet cut from a border in the process of straightening it.

randle bar A horizontal iron bar, built into a jamb of a fireplace, that projected over the fire so that pots could be suspended from it for cooking; also see chimney hook, fireplace crane, trammel.

random ashlar Masonry in which rectangular stones are set without continuous joints and appear to be laid without a fixed pattern; also called random bond or random work.

random bond See random ashlar.

random course One of a number of horizontal stone masonry courses which are of unequal height.

random length In piping, see mill length.

random line In surveying, a trial line toward a fixed terminal point which is invisible from the initial point.

random noise A type of noise comprised of transient disturbances which occur at random times; its instantaneous magnitudes are specified only by probability distribution functions which give the fraction of the total time that the magnitude lies within a specified range.

random paving Paving using irregularly shaped stones.

random range ashlar Same as random work.

random rubble Same as rubblework.

random shingle One of many shingles of uniform length, but of any width.

random slate One of many slate shingles installed in irregular pattern, using varying sizes.

random tooled ashlar See random work.

random widths Boards, lumber, shingles, etc., of nonuniform widths.

random work, broken ashlar, random range ashlar, random range work 1. Random stonework. 2. Masonry of rectangular stone not laid in regular courses, but broken up by the use of stones of different heights and widths, fitted closely.

range 1. In masonry, a row or course, as of stone. 2. A line of objects in direct succession, as a range of columns.

range closet A latrine having a number of seats.

ranged rubble Same as rubblework.

range hood An open metal enclosure over cooking surfaces through which air is drawn in from the surrounding spaces, entraining grease, heated air, and odors.

range-in, wiggling-in A trial-and-error procedure for placing a surveyor’s instrument on a previously established line.

range masonry, rangework See coursed ashlar.

range pile A pile which serves as a guide for locating other piles.

range pole Same as range rod.

ranger Same as wale.

range rod, range pole A wood, fiberglass, aluminum, or steel lining pole used by surveyors as a sighting rod for locating points or directions of lines in marking alignment; approx. 1 in. (2.5 cm) thick and 6 to 10 ft (approx. 2 to 3 m) long; usually painted with alternate red and white bands.

rangework Masonry in which the stones are of equal height within each course, but all courses need not be of the same height.

ranging bond In masonry, a chain bond formed by small strips of wood at the face of the wall, commonly laid in the joints, and projecting slightly to provide a nailing surface for battens, furring, etc.

ranging pole Same as range rod.

ranked A term preceded by a digit (usually from two to nine) that indicates the number of windows across an upper floor of the façade of a house. For example, a six-ranked house has six windows across the upper floors; on the ground floor, the entry door is tallied as one of the windows, so it has five windows plus the door.

rapid-curing asphalt Liquid asphalt composed of asphalt cement and a naphtha or gasoline-type diluent of high volatility.

rapid-curing cutback Same as rapid-curing asphalt.

rapid-hardening cement A high-early-strength cement.

rapid-start fluorescent lamp A fluorescent lamp designed for operation with a ballast having a low-voltage winding for preheating the electrodes and for initiating an arc; may be operated on preheat fluorescent circuits; does not require a starter or the use of high voltage.

rasp A coarse file having its surface dotted with protruding pointed teeth.

ratchet brace A brace, 3 with a ratchet-driven chuck, permitting its use in confined spaces where complete circular sweeps of an ordinary brace would be impossible.

ratchet drill A hand-driven drill, 1 which has a ratchet-driven chuck; used in confined spaces.

ratchet screwdriver See spiral ratchet screwdriver.

rated current The current that an electrical device can carry, under specified conditions, without resulting in overheating or mechanical overstress.

rated horsepower Of an engine or prime mover, the maximum horsepower that can be provided under normal, continuous operation.

rated lamp life 1. The average life of a lamp of a given type, as determined from a large sample operated under laboratory conditions; the average life of a group of lamps which are operated under variable conditions may not equal the rated lamp life. 2. For lamp types whose luminous output drops to a very low value before the lamps cease to operate: the time when the output of a large sample of lamps under controlled laboratory conditions reaches a specified fraction of the initial output.

rated load In vertical transportation, the load in pounds or kilograms which an elevator, lift, dumbwaiter, or escalator is designed to lift at its rated speed.

rated speed The speed in feet (or meters) per minute at which a device, apparatus, conveyance, elevator, etc., is designed to operate in the upward direction with the rated load.

rate of decay Same as decay rate.

rate of growth Same as growth rate.

rath A primitive fort in Ireland, many of which still exist today; the defensive structure includes ramparts of stone or earth as well as some rudimentary form of housing.

rating correction factor The fraction by which the rated electrical load or current must be multiplied to obtain the appropriate figure to estimate the total load for design purposes.

ratio of reduction See reduction ratio.

rat stop In masonry wall construction, a barrier to prevent rats from burrowing down along the exterior of a foundation wall.

rat-trap bond A modification of Flemish bond with the stretchers laid on edge.

rauchkammer A room in a garret in a Pennsylvania Dutch colonial house that was set aside for the curing of meat. An opening in the chimney stack that passed through this space allowed smoke to enter the garret, and the meats to be cured were hung from hooks attached to the underside of the roof framing.

ravelin, demilune In fortifications, a projecting outwork forming a salient angle.

raveling In asphalt pavement, the progressive disintegration by the dislodgement of aggregate particles, from the surface downward or from the edges inward.

raw brick An unfired brick, before it has been inserted in a kiln.

raw linseed oil Linseed oil which has been refined but has not undergone further treatment, such as boiling, blowing, or bodying.

Rawl plug A proprietary name for a concrete insert.

raw sewage Untreated sewage.

raw water 1. In ice making, any water used for ice making except distilled water. 2. Water, from any source, that requires treatment before it can be used, e.g., as in steam generation.

ray See medullary ray.

rayon Continuous-filament yarn composed of regenerated cellulose; similar in chemical structure to natural cellulose fiber but contains shorter polymer units; usually made by the viscose process.

Rayonnant style The middle phase of French Gothic architecture in the 13th and 14th cent., characterized by radiating lines of tracery.

RBM Abbr. for reinforced brick masonry.

RC, R/C Abbr. for reinforced concrete.

RC asphalt Same as rapid-curing asphalt.

RC curves (room criterion curves) A series of curves of octave-band sound spectra; used to provide a single-number rating of the noisiness of an indoor space. A measured octave-band spectrum is compared with this set of curves to determine the RC level of the space in which the measurements were made.

RCD Abbr. for “residual current device.”

RCP Abbr. for “reinforced concrete pipe.”

¼ RD On drawings, abbr. for quarter-round.

½ RD On drawings, abbr. for half-round.

RD 1. Abbr. for roof drain. 2. On drawings, abbr. for “round.”

reach The section of a sewer between structures.

reach-in refrigerator A prefabricated reach-in compartment for cooling food and/or beverages.

reaction pile Same as anchor pile.

reaction wood Wood which results from abnormal growth.

reactive aggregate Aggregate containing substances capable of reacting chemically with the products of solution or hydration of the portland cement in concrete or mortar under ordinary conditions of exposure; in some cases causes harmful expansion, cracking, or staining.

reactive concrete aggregate See reactive aggregate.

reactive silica material Any material, such as fly ash, natural pozzolan, or pulverized silica, which reacts at high temperatures with portland cement or lime during autoclaving.

reader’s desk The middle desk in a three-decker pulpit.

readily accessible Providing direct access (e.g., to piping, wiring, air-conditioning controls, etc.) without requiring the removal or movement of a panel or similar obstruction.

ready condition Said of a wet alarm valve in a fire sprinkler system in which the piping is filled with water from a water supply of stable pressure; in this condition, there is no water flow from any outlet of the system downstream from the alarm valve sealing assembly.

ready-cut house Same as prefabricated house.

ready-mixed See mill-mixed.

ready-mixed concrete Concrete for delivery to a site in an unhardened state for immediate use.

ready-mixed glue See mixed glue.

real estate Property in the form of land and all its appurtenances, such as buildings erected on it.

real property Land, everything growing on it, and all improvements made to it. It usually includes rights to everything beneath the surface, and at least some rights to the airspace above it.

reamer A tapered bit having sharp, spiral, fluted cutting edges along the shaft; used to enlarge an opening, to cut the burrs from the inside of pipe, etc.

reaming iron A reamer for use in enlarging rivet holes.

rear arch 1. An inner arch of an opening which is smaller in size than the external arch of the opening and may be different in shape. 2. See arrière-voussure.

rear girt A girt that runs horizontally along the rear wall of a house; see illustration under timber-framed house.

rear vault 1. A small vault, 1 over the space between the tracery or glass of a window and the inner face of the wall. 2. An arrière-voussure. (See illustration p. 800.)

rear yard The yard across the full width of a plot, extending from the rear line of a building to the rear property line.

reasonable care and skill See due care.

reason piece Same as raising piece.

rebar A steel bar having ribs or slightly projecting patterns on its surface to provide a greater bond with concrete when used in reinforced concrete.

rebate See rabbet.

rebound Wet shotcrete which bounces off a surface against which it is projected.

receipt of bids The formal action taken by an owner in receiving sealed bids that have been invited or advertised in accordance with the owner’s intention to award a contract.

receptacle A device which is installed in an outlet box to receive a plug for the supply of electric current to an appliance or portable equipment.

receptacle outlet An electrical outlet where one or more receptacles are installed.

receptacle plug A device, usually connected to an electric cord, which is inserted in a receptacle to establish an electric connection with the electrical supply.

reception wall Same as retention wall.

receptor 1. A channel-shaped, telescoping member which adapts the frame of a window to the size of the window opening; an adapter. 2. The shallow base pan for a shower.

receptorium A kind of parlor which usually adjoined an ancient Roman basilica.

recess 1. Any shallow depression in a surface. 2. A shallow depression in a floor; a sinkage.

recess bed See wall bed.

recessed arch An arch with a shorter radius set within another of the same shape.

recessed bead See quirk bead, 2.

recessed column A round column set into a recessed space that serves as a niche; primarily in a church.

recessed dormer A dormer, part or all of which is set below the main roof surface; also called an inset dormer.

recessed fitting Same as drainage fitting.

recessed fixture A lighting fixture which is recessed into a ceiling so the lower edge of the fixture is flush with the ceiling.

recessed head For a mechanical fastener, a head having a specially formed indentation which is centered in its top surface.

recessed heater A self-contained heating unit (see electric heating elements), set into a wall.

recessed joint Same as recessed pointing.

recessed luminaire See recessed fixture.

recessed pointing In masonry, a joint in which the mortar is pressed back, about ¼ in. (6 mm) from the wall face, to protect the mortar from peeling.

recessed sprinkler In a fire-protection system, one of many pendant sprinklers located within cups recessed into the ceiling.

recharge, groundwater recharge The replenishment of water in the ground, e.g., through injection or infiltration from trenches outside the construction area.

reciprocating drill Same as push drill.

reciprocating saw Similar to a saber saw but with a heavier blade and a motor with greater power.

recirculated air Air which is withdrawn from an air-conditioned space and passed through the air conditioner before being supplied once again to the conditioned space.

recoating time The minimum time between the application of one coat of paint and the application of the next coat.

reconditioned wood Hardwood lumber that has been steam-dried to correct defects, such as collapse, warp, etc., that occurred during the original drying process.

reconstituted marble See artificial stone.

reconstituted stone Same as artificial stone.

reconstruct To reproduce a building in the same form and detail as it had been previously.

reconstructed stone Same as artificial stone.

record drawings Construction drawings revised to show significant changes made during the construction process, usually based on marked-up prints, drawings, and other data furnished by the contractor to the architect.

record sheet On a construction job, a sheet or printed form for keeping a record, usually of materials delivered, number of men working at the various trades, hours worked, etc.

recovery capacity See heating capacity.

RECP On drawings, abbr. for receptacle.

rec. room Abbr. for “recreation room.”

rectangular tie A wall tie of heavy wire that has been bent into the shape of a closed rectangle, about 2 in. by 6 in. (5 cm by 15 cm).

Rectilinear style See Perpendicular style.

rectilinear tracery See perpendicular tracery.

rectory The residence of a rector.

recycled concrete Hardened concrete which has been crushed for re-use as an aggregate.

redan A diminutive ravelin.

red brass, rich low brass A metal alloy containing 85% copper and 15% zinc; has high corrosion resistance; can take a high polish; generally available in flat sheets, rod, wire, and tube.

red cedar See eastern red cedar.

red fir Same as Douglas fir.

red gum Same as gum, 1.

red heart Decayed heartwood; in some woods it is red in color although it is commonly called brown rot.

red lauan See Philippine mahogany.

red lead A lead compound, lead tetroxide; bright red to orange-red in color; used in corrosion-resistant paints as a rust inhibitor on iron and steel.

red locust See locust.

red oak An oak of eastern North America; the wood is a light brown or red color; relatively heavy, hard, strong, coarse-grained; used esp. for clapboards, also for interior finish.

red ocher A mixture of hematites; any of a number of natural earths used as red pigments.

redoubt A small fortification detached from the principal site.

red oxide A natural or synthetic inorganic red pigment; used in paints to provide a lightfast color at a low cost; grades vary in purity, particle size, and brightness.

red rosin paper A type of building paper.

red-shortness Brittleness of iron or steel at a red hot temperature.

redevelopment The restoration and improvement of an existing structure or property.

reduced level The level at a construction site after excavation, usually with respect to a given datum.

reducing power A measure of the strength of a white pigment in making another pigment appear lighter in color.

reduced-pressure-principle backflow preventer A backflow preventer that consists of two independently-operating check valves that are spring-loaded in a closed position and are separated by a chamber in which there is an automatic relief vent to the atmosphere that is spring-loaded in the open position.

reduced size vent A dry vent that is smaller than one specified by code.

reducer 1. A thinner or solvent; used to lower the viscosity of a paint, varnish, or lacquer. 2. A reducing pipe. 3. A reducing valve.

reducing coupling Same as reducer, 2.

reducing joint A joint between two lengths of electric conductors of unequal size.

reducing pipe A pipe coupling, with inside threads, having one end with a smaller diameter than the other; both openings have the same center line; for connecting pipes of different size.

reducing pipe fitting Any fitting, 1 which is used to connect pipes of different size.

reducing socket Same as a reducing pipe fitting.

reducing valve See pressure-reducing valve.

reduct A small piece cut from a larger piece, member, etc., to make it more uniform or for symmetry.

reduction of area The difference between the original cross-sectional area of a test specimen before being subjected to tension and the area of its smallest cross section after rupture; expressed as a percentage of the original cross-sectional area of the specimen.

reduction ratio In stone crushing, the ratio of the maximum dimension of stone before crushing to the maximum dimension after crushing.

redwood A very durable, straight-grained, high-strength, moderately low-density softwood from the Pacific Coast of the US; esp. resistant to decay and insect attack; light red to deep reddish brown in color; used primarily for construction, plywood, and millwork, where durability is required.

redwood bark Shredded bark of the redwood tree; sometimes used as loose-fill thermal insulation.

reed 1. A small convex molding, usually one of several set close together to decorate a surface. 2. (pl.) Same as reeding. 3. A straw-like material prepared for thatching a roof.

reed house Same as brush house.

reeding An ornament of adjacent, parallel, protruding, half-round moldings (reeds); the reverse of fluting. Also see cabling.

reel and bead See bead and reel.

reentrant angle An internal angle usually less than 90°.

reentrant corner An internal or inside corner; usually used to describe angles less than 90°.

REF On drawings, abbr. for “refer” or “reference.”

refectory A hall in a convent, monastery, or public secular institution where meals are eaten.

reference line Any line which can serve as a reference or base for the measurement of other quantities.

reference mark A supplementary mark of permanent character close to a survey station, to which it is related by an accurately measured distance and azimuth (or bearing); the connection between a survey station and its reference mark or marks must be of sufficient precision and accuracy to permit the reestablishment of the station on the ground from its marks.

reference standards Technical and generic data published by a technically competent organization (such as the ASTM or BRE) that are generally accepted by the building construction industry; they provide acceptability criteria by which products or materials may be evaluated.

reference standard specification A nonproprietary specification based on accepted standards, or on requirements set by an acceptable authority, which describes products, materials, or pieces of equipment to be incorporated in a building project.

reference temperature In the definition for degree-day, an indoor temperature of 65°F (18.3°C) in the US, or 60° (15.6°C) in Britain.

refined tar 1. Tar from which water has been evaporated or distilled until a desired consistency is reached. 2. A bituminous product produced by fluxing tar residuum with tar distillate.

reflash The reignition of a flammable material by a hot source after the flames have been extinguished.

reflectance The ratio of the reflected flux to the flux incident on a surface.

reflectance coefficient, reflectance factor Same as reflectance.

reflected glare Glare resulting from specular reflection of high brightness in polished or glossy surfaces in the field of view. Also see specular surface.

reflected plan A plan, viewed from above, laid out as if it were projected downward on an upper surface (such as a ceiling); thus a member seen on the left from below appears to the right on the plan.

reflection The change of direction which a ray of light, sound, or radiant heat undergoes when it strikes a surface; also see law of reflection.

reflective glass Window glass which has been coated on the outside with a transparent metallic coating to reflect a significant fraction of the light and radiant heat which strikes it.

reflective insulation 1. Thermal insulation in sheet form which has one or both surfaces faced with a reflective foil of comparatively low heat emissivity; used in building construction with a reflective surface facing an air space, to reduce the transfer of heat (by radiation) across the air space. 2. Thermal insulation whose performance depends on the reduction of transfer of radiant heat across air spaces by the use of one or more surfaces having high thermal reflectance and low emittance.

reflectometer A photometer for measuring the reflectance of a material.

reflector 1. A device that redirects light or sound by reflection. 2. The device on a luminaire which controls the distribution of light from the lamp by reflection.

reflector lamp An incandescent lamp in which part of the bulb serves as a reflector, e.g., a PAR lamp.

reflux valve See check valve.

REFR 1. On drawings, abbr. for refractory. 2. On drawings, abbr. for “refrigerate.”

refraction The change in direction of a light ray or a sound ray in passing from one medium to another.

refractory A material, usually nonmetallic, used to withstand high temperatures.

refractory aggregate A material having refractory properties; when bound together into a conglomerate mass by a matrix, forms a refractory body.

refractory brick A brick capable of withstanding high temperatures.

refractory cement Cement esp. manufactured for use in furnace and oven linings; often a mixture of fireclay with crushed brick, silica sand, or sodium silicate.

refractory concrete Concrete having refractory properties; suitable for use at high temperature; usually made with calcium aluminate cement and refractory aggregate.

refractory insulating concrete Refractory concrete having low thermal conductivity.

refractory insulation Thermal insulation which may be used at temperatures above 1500°F (816°C).

refractory materials Materials (such as bricks or blocks) that do not deform significantly or change chemically when subject to high temperatures.

refractory mortar A mortar having refractory properties that make it suitable for use at high temperatures.

refrigerant The medium of heat transfer in a refrigeration system which absorbs heat by evaporation at low temperature and pressure and gives up heat on condensing at higher temperatures and pressures.

refrigerant charge The quantity of refrigerant in a refrigeration system.

refrigerant compressor unit A packaged unit comprising a pump suitable for compressing refrigerant gas, associated controls and accessories, and a prime mover which may be an integral part of the compressor or mounted with the compressor on a common base.

refrigerant condenser See condenser.

refrigerant condensing unit See condensing unit.

refrigerating medium Any substance whose temperature is such that it is used to lower the temperature of other bodies or substances below the ambient temperature.

refrigeration The process by which heat is absorbed from a body or substance by expansion or vaporization of a refrigerant, lowering its body temperature and maintaining the temperature below its surroundings.

refrigeration cycle A repetitive sequence of thermodynamic processes in which a refrigerant absorbs heat from a controlled space at relatively low temperature; then the heat is rejected elsewhere at a higher temperature, and the process is repeated.

refrigeration system A closed-flow system in which a refrigerant is compressed, condensed, and expanded to produce cooling at a lower temperature level and rejection of heat at a higher temperature level for the purpose of extracting heat from a controlled space.

refrigerator A container and a means of cooling it, such as a commercial refrigerator, service refrigerator, etc.

refurbish To make fresh again without demolition and replacement of the original building; i.e., to renovate.

refusal The depth below which a pile cannot be driven.

refuse An approximately even mixture of garbage and rubbish by weight; contains up to 50% moisture and 7% incombustible solids. Also see trash.

refuse chute A means of transporting waste materials by chute, from the point of disposal in high-rise residential (or office building) to a refuse collection room at the base of the chute. See also gravity-type refuse chute.

refuse compactor A motor-driven machine having a ram that reduces the volume of waste material by subjecting it to pressure and forcing it into a removable container or package.

Reg Abbr. for “regular.”

REG 1. On drawings, abbr. for register. 2. On drawings, abbr. for “regulator.”

Regency Revival A mode of Revival architecture, found to a limited extent in America in the 1930s, that borrowed features of its Georgian and Regency style prototypes; usually two stories high with a hipped roof; had brick walls with quoins at the corners and sometimes at the main entrance, often painted white; double-hung windows with shutters; an entrance porch; and, typically, a small octagonal window above the door.

Régence style The decorative and elegant Rococo style flourishing under the regency of Philip of Orleans (1715–1723) during the minority of Louis XV.

Regency style The colorful neoclassic style, often combined with oriental motifs, prevalent in England between 1811 and 1830, during the Regency and reign of George IV. Later, very occasionally emulated in America as Regency Revival; often combined with oriental motifs.

regenerative heating Heating by the use of heat which is rejected in one part of the cycle and utilized in another part of the cycle, by heat transfer.

regia On the ancient Roman theater stage, the central door, leading to the palace of the main hero; the royal door.

register 1. A grille having a damper, 1 for regulating the quantity of air passing through it. 2. A list of buildings, constructions, objects, or sites that are of historic local, state, provincial, or national interest. Such lists are maintained by designated governmental agencies.

registered architect Same as architect, 2.

regle A groove or channel by which the movement of anything, as that of a sliding or lifting door or sash, is guided.

reglet 1. A fillet or small flat-faced projection, as used in a fret molding or to cover a joint between two boards. 2. A raggle.

regrating The cleaning of masonry by removing a thin surface layer, exposing fresh stone.

regressed luminaire A luminaire which is mounted above the ceiling with its opening above the ceiling line.

regula In the Doric entablature, one of a series of short fillets beneath the taenia, each corresponding to a triglyph above.

regular coursed rubble Same as coursed ashlar.

regulated-set cement A hydraulic portland cement which contains an additive to control its set and early strength.

regulating valve A valve that regulates or closes off the flow of a fluid.

regulation Any rule prescribing permitted or forbidden conduct, whether established by legislation or the action of an administrative agency; also see building code.

regulator In a gas supply system, a device for controlling and maintaining a uniform gas supply pressure.

regulus metal See antimonial lead.

rehabilitation The process of returning a building to its original state of utility by means of repair or alteration.

reheat coil 1. In an air-conditioning system, a coil which heats air in the supply duct to control its temperature. 2. A coil which is heated to control the temperature of air being furnished to individual zones, 1.

reheating In an air-conditioning system, the heating of air which has already been conditioned, e.g., the heating of air supplied to one zone of the system in order to maintain temperature control in that zone.

reimbursable expenses Amounts expended for or on account of the project which, in accordance with the terms of the appropriate agreement, are to be reimbursed by the owner.

REINF On drawings, abbr. for “reinforce” or “reinforcing.”

reinforced bitumen felt A light roofing felt saturated with bitumen and reinforced with a jute cloth.

reinforced blockwork In masonry, blockwork in which steel reinforcement is added to resist tensile, compressive, or shear stresses.

reinforced brick masonry See reinforced-grouted brick masonry.

reinforced brickwork Any joints in brickwork that are given extra strength, usually by metal bars, mesh, rods, or wires across the joints.

reinforced cames Lead bars reinforced with a steel core; used in leaded lights.

reinforced column A concrete column containing reinforcement such as steel rods or wire mesh.

reinforced concrete, beton armé, ferroconcrete, steel concrete Concrete containing reinforcement designed on the assumption that the concrete and reinforcement act together in resisting forces.

reinforced concrete joint A concrete joint that is bridged by reinforced steel embedded in both sides of the joint.

reinforced concrete masonry Concrete masonry construction in which steel reinforcement (in excess of a specified minimum percentage) is so embedded that the materials act together in resisting forces. Where hollow concrete masonry units are used, certain cores (including those containing the embedded reinforcement) are filled solidly with grout. In multiwithe construction in which the reinforcement is embedded between the withes, the space between the withes is filled solidly with grout.

reinforced-grouted brick masonry, reinforced brick masonry Grouted brick masonry in which reinforcement is provided in the horizontal joints and in grouted vertical joints between withes.

reinforced masonry Masonry units in which reinforcement, usually steel mesh or rods, is embedded in such a manner that the two materials act together in resisting forces.

reinforced membrane A roofing or waterproofing membrane which is reinforced with felts, mats, fabrics, fibers, or the like.

reinforced plastic A plastic having imbedded high-strength fillers to provide mechanical properties which are superior to those of the base material.

reinforced T-beam A concrete T-beam that has been reinforced with steel rod before the concrete is poured.

reinforcement 1. In reinforced concrete, metal bars, rods, wires, or other slender members which are embedded in concrete in such a manner that the metal and the concrete act together in resisting forces. 2. Material added to provide additional strength.

reinforcement displacement The movement of steel reinforcement in the forms from its specified position.

reinforcement ratio At any section of a reinforced concrete structural member, the ratio of the effective area of the reinforcement to the effective area of the concrete.

reinforcement schedule Same as bending schedule.

reinforcement weld Along a groove weld, weld metal in excess of the specified weld size.

reinforcing arch An arch that reinforces a tunnel vault.

reinforcing bar A steel bar used in concrete construction (e.g., in a beam or wall) to provide additional strength; also see deformed bar, reinforcing rod.

reinforcing plate An extra plate used to reinforce or strengthen a member.

reinforcing rod Any of a variety of steel rods used in reinforced concrete.

reinforcing tape A high-strength tape which resists stretching, wrinkling, and tearing; lies flat and may be lightly sanded; may be used to add strength and crack resistance along flat joints and inside corners.

reinforcing unit In a metal door, a box-shaped reinforcement in which a bored lock is installed; provides support for the latch, both vertically and horizontally.

reja In Spanish architecture and its derivatives, a grille or grating over windows facing the street, often projecting from the face of a house into the street.

rejointing Same as repointing, 3.

relamp To replace one or more electric bulbs in a lighting system.

relamping See spot relamping and group relamping.

related trades In building construction, trades whose work is required to complete a system within a building (such as a HVAC system), part of a building, or the entire project; or trades using similar tools.

relative compaction The dry density of soil in the field expressed as a percentage of the density of the soil after it has been subjected to a standard amount of compaction.

relative consistency Of a soil, the ratio of the liquid limit minus the natural water content to the plasticity index.

relative density For a given void ratio of soil, the ratio between: (a) the difference between the void ratio of the soil in its loosest state and the given ratio and (b) the void ratio in the loosest state minus the void ratio in the densest state.

relative humidity The ratio of the weight of water vapor actually in humid air to the maximum possible weight of the water vapor that the air could contain at the same temperature; usually expressed as a percentage.

relative settlement See differential settlement.

relaxation of steel 1. The decrease in stress in steel as a result of creep within the steel under prolonged strain. 2. The decrease in stress in steel as a result of decreased strain of the steel, such as results from shrinkage and creep of the concrete in a prestressed concrete unit.

relay An electromechanical device in which changes in the current flow in one circuit (that flows through the device) are used to open or close electric contacts in a second circuit.

release agent In formwork, any material that is used to prevent the bonding of concrete to a surface.

release of lien Instrument executed by one supplying labor, materials, or professional services on a project which releases his mechanic’s lien against the project property. Also see mechanic’s lien.

release paper A protective sheet having an adhesive film on one side; may be easily removed from the surface to which it is applied.

relief Sculptured work, carving, casting, or embossing that is raised above the plane of its background. Also called relievo; see bas-relief, demi-relief, high relief, mezzo-relievo, sunk relief.

relief cut A preliminary cut with a jig saw or band saw to prevent the saw from binding, when cutting a curve in a piece of wood.

relief damper, relief opening A damper in an air-conditioning system which opens automatically, relieving the buildup of air pressure within the building or air-conditioned space.

relief grille See relief damper and relief opening.

relief map, hypsometric map A map depicting the configuration of the earth’s surface, called the “relief,” by means of contours, form lines, hachures, shading, tinting, or relief models.

relief opening See relief damper.

relief valve A valve installed in a system to relieve pressure in excess of a preset limit by discharging a portion of the contents of the system.

relief vent A branch from the vent stack, connected to a horizontal branch between the first fixture branch and the soil or waste stack, whose primary function is to provide for circulation of air between the vent stack and the soil or waste stack.

relieve To lighten a color in order to reduce its intensity.

relieved work Ornamentation done in relief.

relieving arch Same as discharging arch.

relievo Same as relief, 1.

relish In carpentry and joinery, the projection or shoulder at the side of, or around, a tenon.

relocatable partition See demountable partition.

REM On drawings, abbr. for “removable.”

remainder An interest in property that confers a right to possession in someone other than the grantor or his heirs upon the termination of a prior interest, such as following the death of a life tenant.

remodeling See alterations.

remoldability The ease with which freshly mixed concrete responds to an effort to remold it, as by jigging or by vibration, causing it to reshape its mass around reinforcement and to conform to the shape of the formwork.

remolded soil Soil that has had its natural structure modified by manipulation.

remolding test A test to determine the remoldability of concrete.

remote-control circuit An electric circuit that controls another circuit which is at a distance.

remote-entry system An electrically-controlled door lock that includes a means for supervising its operation by some type of identification check, such as an intercommunication system, closed circuit TV, or key-card reader.

remote station system An electronic fire alarm system capable of notifying the fire department when the system is activated by a fire.

removable mullion A door mullion which can be removed temporarily from a doorframe to permit large objects to be moved through the frame.

removable stop 1. A stop which is removable to permit the installation of a glass pane, fixed panel, or door. 2. A glazing bead, 2.

Renaissance architecture, Renaissance Classical architecture The architectural style developed in early 15th cent. Italy during the rebirth (rinascimento) of classical art and learning. It succeeded the Gothic as the style dominant in all of Europe after the mid-16th cent., and evolved through the Mannerist phase into Baroque and in the early 17th cent. into classicism. Initially characterized by the use of the classical orders, round arches, and symmetrical composition.

Renaissance Revival A term occasionally used as a synonym for Italian Renaissance Revival.

render 1. To give a mechanical drawing, as in elevation, a more or less complete indication of shades and shadows; in ink, color, or other media. 2. To apply plaster directly to brickwork, stonework, tile, etc.; esp. to apply the first coat.

render coat See scratch coat.

render, float, and set Three-coat plastering executed directly on stone or brick.

render and set To apply two-coat plastering directly on stone or brick walls.

rendered Said of any piece of wood that is split rather than sawn.

rendered brickwork Brickwork which has been coated with a facing of waterproof material.

rendering 1. Applying a coat of plaster directly on an interior wall or stucco on an exterior wall. 2. A perspective or elevation drawing of a project or portion thereof with artistic delineation of materials, shades, and shadows.

rendering coat The first coat of plaster on brickwork or stonework.

rendu An architectural rendering of a design problem.

renovation The restoration of a building to its almost new condition.

rent See lease.

rent lath Lath which has been split instead of sawn.

rent pale A narrow wood strip, esp. of oak which has been split instead of sawn.

REP. On drawings, abbr. for “repair.”

repair Replacement or renewal (excluding additions) of any part of a building, structure, device, or equipment with like or similar materials or parts, for the purpose of maintenance of such building, structure, device, or equipment.

repeating theodolite A theodolite so designed that successive measures of an angle may be accumulated on the graduated circle, and a final reading of the circle made which represents the sum of the repetitions.

REPL On drawings, abbr. for “replace.”

replum In door construction of the ancients, an upright rail (from sill to lintel) which divides a doorframe in two parts; used with a door having two leaves, which close against it.

repointing Same as pointing, 3.

repoussé Raised in relief by embossing or by beating on the underside with a hammer.

reprise In masonry, the return of a molding in an internal angle.

REPRO On drawings, abbr. for “reproduce.”

reproducible Said of a drawing, copy, or the like, which is capable of being used as a master-to-be in a reproduction process.

REQD On drawings, abbr. for “required.”

request for information A formal request in writing, from the contractor to the architect, asking for information.

requisition See application for payment.

rere-arch Same as rear arch.

reredorter A privy behind a monastery or convent.

reredos An ornamental screen or wall at the back of an altar.

reredosse In an ancient hall, the open hearth upon which a fire was lit, immediately under the louver, 2.

res In the lumber industry, abbr. for “resawn.”

resealing trap On a plumbing-fixture drain pipe, a trap, 1 which is designed so that the rate of flow at the end of a discharge from the fixture seals the trap but does not cause self-siphonage.

reservoir A receptacle or enclosed space for the collection or retention of water, which is supplied to it by natural springs, drainage, or artificial means.

reshoring A temporary vertical support for forms or a completed structure, placed after the original shoring support has been removed.

residence casement 1. Any casement used in residential construction. 2. A lightweight, relatively low-cost, steel or aluminum casement window.

resident engineer A person representing the owner’s interests at the project site during the construction phase; a term frequently used on projects in which a governmental agency is involved. Also see owner’s inspector.

residential-custodial care facility A building, or part thereof, used for the lodging or boarding of four or more persons who are incapable of self-care because of age or physical or mental limitation.

residential occupancy Occupancy of a building in which sleeping accommodations are provided for normal residential purposes; includes all buildings designed to provide sleeping accommodations except those classified under institutional occupancy.

resident inspector 1. See owner’s inspector. 2. See resident engineer.

residual deflection A deflection resulting from an applied load which remains after the removal of the load.

residual deformation The nonreversible deformation that remains in hardened concrete after a sustained load has been removed.

residual soil Soil formed in place by weathering of the underlying mineral materials.

residual sound The composite sound from many sources and many directions (near and far) remaining when all uniquely identifiable discrete sound sources are eliminated.

residual stress A stress that remains in an unloaded member after it has been formed into a finished product, such as that induced in steel shapes by cold bending, cooling after rolling, or welding.

residual tack See aftertack.

resilience The ability of a body that has been subjected to an external force to recover its size and shape, following deformation.

resilient channel In sound-insulating construction, a fabricated metal strip having two faces with flexible interconnection; used for attaching gypsum board to studs or joists without a solid connection so as to reduce the transmission of noise and vibration.

resilient clip In sound-insulating construction, a flexible metal device for attaching gypsum board or metal lath to studs or joists to reduce transmission of noise and vibration.

resilient connector In a piping system, a flexible connector which joins pipe to another pipe that is subject to vibration or joins a pipe to a pump; can be deformed and deflected without leakage or rupture.

resilient floor A wood floor, laid on battens, having the quality of springiness (e.g., a floor supported by spring clips); especially used as a dance floor, gymnasium floor, etc.

resilient flooring A manufactured interior floor covering, in either tile or sheet form, which is resilient.

resilient hanger 1. See resilient clip and resilient channel. 2. A hanger, 1 which incorporates a metal or elastomer spring, providing a resilient method of attachment.

resin A nonvolatile solid or semisolid organic material, usually of high molecular weight; obtained as gum from certain trees or manufactured synthetically; tends to flow when subjected to heat or stress; soluble in most organic solvents but not in water; the film-forming component of a paint or varnish; used in making plastics and adhesives.

resin-bonded Descriptive of timber which has been glued with a synthetic resin.

resin chipboard A particleboard in which the binder for the wood chips is a resin.

resin concrete Concrete in which an organic polymer is used as the binder.

resin-emulsion paint A water paint consisting of a water emulsion of an oil-modified alkyd or other resin; when dry, leaves a tough film of resin.

resin-impregnated wood, resin-treated wood Wood whose fibers are impregnated with synthetic resin to provide improved hardness, moisture resistance, durability, etc.

resin pocket See pitch pocket.

resin streak See pitch streak.

resin-treated wood See resin-impregnated wood, compregnated wood.

resistance See electrical resistance, thermal resistance, etc.

resistance brazing A brazing process in which the heat required is obtained from the resistance to electric current in a circuit of which the work is a part.

resistance welding A group of welding processes in which coalescence is produced by the heat obtained from resistance of the work to the flow of electric current in a circuit of which the work is a part, and by the application of pressure.

resistivity See electrical resistivity.

resistor A device used in an electric circuit to control the flow of current.

resorcinol adhesive An adhesive which is water-soluble for a period of 2 to 4 hr, and then insoluble and chemically resistant.

respond A support, usually a corbel or pilaster, affixed to a wall to receive one end of an arch, a groin, or a vault rib.

responsible bidder See lowest responsible bidder.

ressant, ressaut 1. Medieval name for ogee, 2. 2. A projection of any member or part from another, such as a projecting portion of a molding. 3. A roll molding.

ressault See ressant.

restaurant A building (or part of a building) or any place used as a place where meals or sandwiches are prepared and/or served to its clientele.

rest bend A right-angle fitting, 1 for a pipe with an integral seat which may be mounted on a support.

restoration See building restoration.

restricted list of bidders See invited bidders.

restriction On land, an encumbrance limiting its use; usually imposed for community or mutual protection.

restrictive covenant An agreement between two or more individuals, incorporated within a deed which stipulates how land may be used. The constraints may include: the specific use to which a property can be put, the location and dimensions of fences, the setback of buildings from the street, the size of yards, the type of architecture, the cost of the house, etc. Racial and religious restrictions on inhabitants are legally unenforceable.

restrictive specification A building specification that limits the purchase of a product to a specific manufacturer or to the purchase of a material from a specific supplier.

restroom A public lavatory.

resurfacing The placing of a supplemental surface on an existing surface to improve its conformation or to increase its strength.

RET. On drawings, abbr. for “return.”

retable A decorative screen set up above and behind an altar, generally forming an architectural frame to a picture, bas-relief, or mosaic.

retainage A sum withheld from progress payments to the contractor in accordance with the terms of the owner-contractor agreement.

retaining wall A wall, either freestanding or laterally braced, that bears against an earth or other fill surface and resists lateral and other forces from the material in contact with the side of the wall, thereby preventing the mass from sliding to a lower elevation. Also see cantilever wall, counterfort wall, gravity wall.

retardation Reduction in the rate of hardening or setting; an increase in the time required to reach initial and final set or to develop early strength of fresh concrete, mortar, plaster, or grout.

retard chamber A device in a fire sprinkler system used to minimize false alarms caused by surges or fluctuations in its water supply system.

retarded hemihydrate A calcined gypsum plaster having a retarder added to control the setting action.

retarder 1. In paint, varnish, or lacquer, a high-boiling solvent used to lower evaporation rate of the volatile ingredients. 2. An admixture which delays the setting of cement paste or the setting of mixtures such as mortar or concrete containing cement. 3. An additive, mixed with plaster to control the rate of hardening.

retarding admixture Same as retarder, 3.

retemper To replace water that has been evaporated from a mortar mix.

retempering 1. The addition of water and remixing of concrete or mortar which has started to stiffen. 2. The addition of a small amount of water to plaster or mortar as it begins to set; improves spread and workability, but weakens the plaster.

retention 1. The withholding of a portion (usually 10%) of a periodic payment to a contractor, by prior agreement, for work completed. The retention is held in escrow for a stipulated time period after the acceptance of the completed work by the architect and owner/payee. 2. The amount of preservative, fire-retardant salt, resin, etc., retained by treated or impregnated wood.

retention basin A depression for temporarily storing storm water in order to reduce the rate of runoff from a drainage area.

retention money Same as retention, 1.

retention wall A thin wall or barrier which forms a gap between it and the external wall of a building (the space between being filled with a waterproofing material).

reticulata fenestra A lattice window protected by small bars of wood or metal that cross each other in a net-like pattern.

reticulated Covered with netted lines; netted; having distinct lines crossing in a network.

reticulated molding A molding decorated with fillets interlaced to form a network or mesh-like appearance.

reticulated tracery Tracery whose openings are repetitive like the meshes of a net.

reticulated work Same as opus reticulatum.

reticulatum opus Same as opus reticulatum.

reticuline bar Of a grating, a sinuously bent connecting bar extending between two adjacent bearing bars.

retractable roof A roof system, usually over an auditorium, designed to roll back the roof on tracks so that the interior of the facility is open to the outdoors.

retrochoir A chapel behind the high altar of a church but in front of the Lady chapel if there is one.

retrofit The addition of new building materials, building elements, and components, not provided in the original construction. See building retrofit.

return The continuation of a molding, projection, member, or cornice, or the like, in a different direction, usually at a right angle. For example, see cornice return and label return.

return air Air returned from an air-conditioned or refrigerated space to the central plant for processing and recirculation.

return air fan A fan which withdraws air from an air-conditioned space and returns it (or part of it) to the central air-conditioning system.

return air grille Same as return grille.

return-air intake An opening through which return air reenters an air-conditioning system; usually provided with a damper to regulate the flow of return air.

return bead The continuation of a bead in a different direction, usually at a right angle. Also see quirk bead.

return bend A pipe fitting, 1 or a preformed piece of tubing which provides a 180° change in direction.

return-circulation system See hot-water recirculation system.

return duct A duct carrying return air.

returned cornice See cornice return.

returned end The end of a molding having a shape which is the same as the profile of the molding.

returned molding A molding continued in a different direction from its main direction.

returned stall See return stall.

return fan A fan that removes air from an air-conditioned space.

return fill Same as backfill.

return grille A grille, 2 through which return air is extracted; usually not provided with an adjustment for volume of airflow.

return head A stone quoin, at the corner of a building, that has the same finish on both the face and the side.

return mains Pipes or conduits which return a heating or cooling medium from the heat transfer unit to the source of heat or refrigeration.

return offset, jumpover In plumbing, a double offset, 3 installed in a pipeline to pass around an obstruction.

return period See average frequency of occurrence.

return pipe In a heating system, a pipe through which water that is produced by the condensation of steam is returned to the boiler.

return stall A stall, 1, in the chancel of a church, facing the high altar; also called a returned stall.

return system 1. An assembly of connected ducts, or passages or plenums, and fittings through which air from an air-conditioned space is delivered to the return fan. 2. In a piping system, the pipes through which water is returned to a pump.

return wall A short wall usually perpendicular to, and at the end of, a freestanding wall to increase its structural stability.

REV On drawings, abbr. for “revise.”

revalé A stone molding, carved in place.

reveal 1. The side of an opening for a door or window, doorway, or the like, between the doorframe or window frame and the outer surface of the wall; where the opening is not filled with the door or window, the whole thickness of the wall. 2. The distance from the face of a door to the face of the frame on the pivot side.

reveal lining Moldings or any other finish applied over a reveal.

reveal pin, reveal tie An adjustable clamp, placed horizontally across an opening in a wall; used to hold scaffolding against the wall.

revel Same as reveal.

revent pipe That part of a vent pipeline which connects directly with an individual waste pipe or group of waste pipes underneath or back of the fixture, and extends to either the main or branch vent pipe; also called an individual vent.

reverberation The persistence of sound in an enclosed space (such as a room or auditorium) after a source of sound has stopped.

reverberation chamber A room, having a long reverberation time, which is especially designed for the measurement of the sound absorption coefficients of an acoustical material or the sound power of a sound source.

reverberation time A measure of reverberation in an enclosed space; the time required for sound-pressure level to decrease 60 dB after the source has stopped.

reverse A template that has the reverse profile of a molding it is intended to match.

reverse-acting diaphragm valve A valve which opens when pressure is applied on a diaphragm and closes when pressure is released.

reverse-acting thermostat An instrument which activates a control circuit upon sensing a predetermined high temperature.

reverse bevel A bevel on the latch bolt or lock of a door, opening outward from a building, etc., which is the reverse of an ordinary lock bevel.

reversed door See reverse-swing door.

reversed loader A front-end loader on a wheel tractor which has the driving wheels in front and the steering wheels at the rear.

reversed zigzag molding A compound ornamental zigzag molding commonly used in Norman architecture.

reverse-flight stair See dogleg stair.

reverse-swing door, reversed door A door which opens in a direction opposite the usual direction; a door to a room which swings outward.

reversible grating A grating which is constructed so that it may be installed with either side exposed, with no difference in appearance or carrying capacity.

reversible lock A lock which, by reversing the latch bolt, may be used either way; on certain types of locks, other parts also must be changed.

reversible window A window in which the sash may be turned so that the glass surface that normally faces the exterior is turned toward the interior for purposes of cleaning.

reversion Chemical reaction leading to the deterioration of a sealant, backup, or filler; due to moisture trapped behind the sealant.

revertible flue A flue or breeching designed so that at some point in the travel of the flue gases they are forced to flow downward instead of in the normal upward direction.

revestry Old form of vestry.

revet To face a sloping wall or foundation, an embankment, or the like, with stone, concrete, or a similar material.

revetment 1. Any facing of stone, metal, or wood over a less attractive or less durable substance or construction. 2. A retaining wall or breast wall; a facing on an embankment to prevent erosion.

revibration One or more applications of vibration to concrete after completion of placing and initial compaction but preceding initial setting.

revision A change made in the working drawings and specifications for a building project subsequent to the start of construction.

Revival architecture Architecture that makes use of elements of an earlier style that it seeks to emulate, borrowing many of the features of its prototype, as described under the term architectural mode. For example, see Adam Revival, American Colonial Revival, American Renaissance Revival, Byzantine Revival, California Mission Revival, Carpenter Gothic Revival, Chateauesque Revival, Classical Revival style, Classic Revival, Colonial Revival, Dutch Colonial Revival, Early Classical Revival, Early Gothic Revival, Early Romanesque Revival, Egyptian Revival, Exotic Revival, Federal Revival, French Revival, Georgian Revival, Gothic Revival, Greek Revival style, International Revival, Italian Renaissance Revival, Jacobethan Revival, Late Gothic Revival, Mediterranean Revival, Mission Revival, Monterey Revival, Moorish Revival, Neoclassical Revival, Neoclassical style, Neoclassicism, Neo-Colonial, Neo-Eclectic, Neo-French, Neo-Georgian, Neo-Gothic, Neo-Grec, Neo-Greek Revival, Neo-Romanesque, Neo-Tudor, Neo-Victorian, Oriental Revival, Period Revival, Pueblo Revival, Regency Revival, Renaissance Revival, Romanesque Revival, Second Renaissance Revival, Spanish Colonial Revival, Spanish Pueblo Revival, Territorial Revival, Tudor Revival, Tuscan Revival.

revolving-blade mixer Same as open-top mixer.

revolving door An exterior door consisting of four leaves (at 90° to each other) which pivot about a common vertical axis within a cylindrically shaped vestibule; prevents the direct passage of air through the vestibule, thereby eliminating drafts from outside.

revolving-drum truck mixer A truck which mixes concrete during its transport to a construction site. Previously proportioned materials from a batch plant are transferred to the truck drum where all mixing takes place.

revolving shelf See lazy susan.

revolving shovel A shovel in which the digging machinery can rotate independently from the supporting structure.

rez-de-chaussée The ground floor of a building.

RF On drawings, abbr. for roof.

Rfg Abbr. for “roofing.”

RFP Abbr. for “request for proposal.”

rgh, Rgh In the lumber industry, abbr. for “rough.”

Rh Abbr. for Rockwell hardness.

RH 1. Abbr. for relative humidity. 2. Abbr. for “right hand.” 3. Abbr. for “round head.”

Rhenish brick A type of lightweight brick.

rheology The science dealing with flow of materials, including studies of deformation of hardened concrete, the handling and placing of freshly mixed concrete, and the behavior of slurries, pastes, and the like.

rheostat An electric device having a resistance which can be adjusted; used to control the flow of electric current, as, for example, in one type of dimmer.

RHN Abbr. for Rockwell hardness number.

rib 1. A curved structural member supporting any curved shape or panel. 2. In vaulted roofs, the moldings which project from the surface and separate the various roof or ceiling panels. 3. A raised ridge or fold which is formed in sheet metal (or a formed section attached thereto) to provide stiffness.

RIBA Abbr. for Royal Institute of British Architects.

riband, ribband Same as ribbon strip.

ribbed arch An arch composed of individual curved members or ribs.

ribbed fluting 1. (Brit.) Flutes alternating with fillets. 2. See cabled fluting.

ribbed panel A reinforced concrete panel composed of a thin slab reinforced by a system of ribs.

ribbed slab Same as ribbed panel.

ribbed vault A vault in which the ribs support, or seem to support, the web of the vault.

ribbing An assemblage or arrangement of ribs, as timberwork sustaining a vaulted ceiling.

ribbing up Laminating circular joinery by gluing up layers of veneer with parallel grain direction.

ribbon 1. A ribbon strip. 2. A long thin strip of wood, or a series of such strips uniting several parts. 3. In stained glass work or the like, a strip or bar of lead to hold the edge of the glass. Also called a came.

ribbon board 1. A ribbon strip. 2. A horizontal member in formwork used to prevent the spreading of a wall box.

ribbon course A course in roofing, in which the exposed depth of tile, slate, etc., from one course to the next is alternately large and small.

ribbon development An urban extension primarily in the form of a single depth of buildings along roads radiating from a city, along a highway between two cities, or along the bank of a river.

ribbon loading In batching concrete, the loading of all the solid ingredients (and sometimes water) into the mixer at the same time.

ribbon rail A metal rail which joins the tops of metal balusters.

ribbon saw Same as band saw.

ribbon strip, girt strip, ledger board, riband, ribband A wood strip or board let into the studs to add support for the ends of the joists; also called a girt strip or ledger board.

ribbon-stripe veneer, ribbon-grained veneer, stripe veneer Wood veneer having alternate light and dark stripes running parallel to the grain. Also see interlocked grain.

ribbon window, ribbon lights On the façade of a building, a horizontal band of at least three windows, separated only by mullions; occasionally called a window band.

ribbon wall Same as serpentine wall.

rib lath, stiffened expanded metal Expanded-metal lath having V-shaped ribs to provide greater stiffness and to permit wider spacing of framing members.

rib vault Same as ribbed vault.

Richardsonian Romanesque style, Romanesque Revival The massive architectural style, from 1880 to 1900 and beyond, as practiced by Henry Hobson Richardson (1838–1886) and his followers; an outgrowth of earlier architecture making use of architectural elements of the Romanesque style, chiefly in public buildings, churches, railroad terminals, and universities designed from 1840 to 1880. Buildings in this style usually exhibit many of the following characteristics: a façade of rough-cut rock-faced masonry, and different colors and textures of stone, occasionally in combination with decorative brickwork; massive semicircular arches, sometimes in combination with flat arches; clustered arches or piers; a decorative tympanum; parapeted gable ends; short, thick columns, occasionally with cushion capitals; bands of engaged colonettes; decorative plaques; a roof covering of slate or tile; one or more cross gables; decorative cresting or decorative tile at the ridge of the roof; a tower with a steep roof and/or topped with a finial; a steeply pitched, hipped roof with little roof overhang at the eaves; a decorative chimney; double-hung windows, often arched or rectangular; deeply recessed window opening; window openings framed by round arches having hooded moldings, often with label stops; often, a circular or semicircular window in a wall gable; doors usually deeply set within massive semicircular or segmental masonry arches ornamented with Romanesque decorations. Also called Neo-Romanesque or Romanesque Revival. See Victorian Romanesque.

rich concrete Concrete having a high cement content.

rich lime A fat lime.

rich low brass See red brass.

rich mix A fat mix.

rich mixture Same as fat mix.

rich mortar A fat mortar.

RICS (Brit.) Abbr. for Royal Institution of Chartered Surveyors.

riddle A sieve, esp. a coarse one for sand.

rider cap Same as pile cap.

rider shore A heavy timber whose lower end abuts another timber laid against the back of the outer raking shore rather than against the ground.

ridge 1. The horizontal line at the junction of the upper edges of two sloping roof surfaces. 2. The internal angle or nook of a vault.

ridge batten Same as ridge roll.

ridge beam A beam at the upper ends of the rafters, below the ridge of a roof; a crown plate, 2. (See illustration p. 818.)

ridgeboard, ridgepole A longitudinal member at the apex of a roof which supports the upper ends of the rafters. Also called a ridge beam, ridgepiece, ridgeplate, or ridgetree.

ridgecap, ridge capping, ridge covering Any covering (such as metal, wood, shingle, etc.) used to cover the ridge of a roof.

ridge course The last or top course of roofing tiles, roll roofing, or shingles.

ridge covering See ridgecap.

ridge crest The ornamentation of the ridge of a roof.

ridge cresting See cresting.

ridge cut See plumb cut.

ridge fillet A fillet between two depressions, as between two flutes of a column.

ridge molding A molding of sheet metal, copper, zinc, or lead which covers the ridge of a roof.

ridge plate A heavy timber, often square in section, that is set directly below the ridge of a roof.

ridgepole See ridgeboard.

ridge purlin 1. Same as ridgeboard. 2. A purlin, placed at the apex of a roof, which rests against the upper ends of the rafters.

ridge rib 1. A horizontal rib marking the crown of a compartment of vaulting, characteristic of English Gothic architecture from the early 13th cent. on, but occasionally found on the Continent. 2. A rib which follows the ridge of a vault.

ridge roll 1. A wood strip, rounded on top, which is used to finish the ridge of a roof; often covered with lead sheeting. 2. A metal, tile, or asbestos-cement covering which caps the ridge of a roof; also called a hip roll or ridgecap.

ridge roof A pitched roof; the rafters meet at the apex of a ridge; the end view is that of a gable roof.

ridge stop In roofing, a metal flashing used at the intersection of a ridge and a wall rising above it.

ridge terrace On a slope, the area behind a contour line of a slope which forms a ridge that retains the rainwater that falls on the slope above it.

ridge tile, crown tile A tile which is curved in section, often decorative, used to cover the ridge of a roof.

ridgetree An archaic form of ridgepole.

ridge ventilator A roof ventilator that straddles a ridge of the roof of a barn; usually square in plan and constructed of wood and/or metal.

ridging 1. In built-up roofing, a failure characterized by long narrow blisters in the roof surface. 2. The covering of the ridge of a roof.

riding house A structure especially designed for teaching the skill of horse riding.

riding shore Same as rider shore.

riding trail See bridle path.

riebeckite asbestos A type of mineral derived from a monoclinic amphibole.

riffler A file which is curved and grooved for working in depressions.

rifle hole A slot in an exterior wall of structures such as blockhouses, forts, and garrison houses, used for defensive purposes. The sides of the slot are splayed so the opening is wider at the inner face of the wall than at the exterior face, permitting a rifleman on the interior to fire over a wide angle.

rift The direction in which stone splits most readily; characteristic of granite or other stone not having visible stratification or foliation.

rift-grained See edge-grained.

rift sawn See quartersawn.

rigger A long-haired, slender brush used in precision painting.

rigging See stage rigging.

rigging line A rope or wire used in stage rigging.

rigging loft A space above the stage of a legitimate theater; designed and used for the flying and storage of scenery and scenic elements.

riggot An open rainwater drain, such as a gutter.

right angle An angle of 90°.

right-hand door See hand.

right-hand lock A lock for use on a right-hand door.

right-hand reverse door See hand.

right-hand stairway A stairway having the rail on the right side, in the ascending direction.

right line A straight line between two points.

right-of-way Any strip or area of land, including surface and overhead or underground space, which is granted by deed or easement for the construction and maintenance of specified linear elements such as power and telephone lines; roadways; gas, oil, water, and other pipelines; sewers.

rigid arch An arch which has no joints, being continuous and rigidly fixed at the abutments.

rigid bent A frame structure that is moment-resisting, i.e., is rigid in two dimensions.

rigid concrete pavement Reinforced portland concrete pavement on a gravel base and subbase; usually has transverse joints for controlling expansion and contraction.

rigid connection A connection between two structural members which prevents one from rotating with respect to the other.

rigid dampproof course Slate or brick that serves as a dampproof course.

rigid foam 1. See cellular plastic. 2. See foamed plastic, 1.

rigid frame A structural framework in which all columns and beams are rigidly connected; there are no hinged joints and the angular relationship between beam and column members are maintained under load.

rigid insulation Thermal insulation whose density is high enough so that a sheet of this insulation will stand upright if supported only along one edge of the sheet.

rigid insulation board See hardboard.

rigid joint A joint between structural members which does not permit relative motion between them.

rigidity That property of a material which resists a change in its physical shape.

rigidized Said of light-gauge sheet metal which is embossed or textured by a rolling process to provide additional stiffness.

rigid lock See preassembled lock.

rigid metal conduit A raceway for electric wires or cables, made of metal pipe of standard thickness and weight permitting the cutting of standard threads.

rigid pavement A pavement which provides high bending resistance and which distributes loads to the foundation over a relatively large area.

riglet Same as reglet.

rim 1. The border or outer edge of anything which is circular or continuously curved. 2. Descriptive of any finish hardware which is designed for application to the face of a door or window, rather than for mortising.

rim joist, rim board A piece of wood, around the perimeter of a wood frame, to which the ends of floor joists are attached.

rim latch A surface-mounted latch.

rim lock A face-mounted door lock. Compare with box lock.

rinceau In classical architecture and derivatives, an ornamental band of undulant and recurving plant motifs.

rind gall A defect in timber caused by a bruise in the bark which produces a callus on the wood over which later layers grow without consolidating.

ring cairn A pile of stones, set in a circle, with an open central space.

ring course In an arch, an outer course of stone or brick.

ringed column See banded column.

ringing chamber A room in the lower part of a church tower where the ropes that ring the church bells are located.

Ringelmann chart A chart used as the basis for evaluating the density of smoke discharged from chimneys.

ring gasket Same as gasket, 2.

ring-groove nail Same as ring-shank nail.

ringhiera In Italian Medieval architecture, a balcony (on the front of the town hall) from which speeches and decrees were read.

ringlock nail Same as ring-shank nail.

ring louver, (Brit.) spill ring In lighting, a louver system in the form of concentric annular rings; used in luminaires having circular apertures.

ring-porous wood Hardwood having spring-wood pores which are larger and more distinct than those produced later in the growing season.

ring scratch awl A scratch awl esp. used in sheet-metal fabrication.

ring shake, cup shake, shell shake, wind shake A separation in wood between or along the annual rings.

ring-shank nail A nail having a number of ring-like grooves around the shank to increase its holding power.

ring stone One of the stones of an arch which show on the face of the wall, or the end of the arch; one of the voussoirs of the face forming the archivolt.

ring-type hanger A type of hanger primarily used to support pipes; either fabricated in one piece or split in two halves which are fastened.

ringwork In medieval times, one or more defensive ditches or banks (usually more or less circular or oval in shape) to protect the area within.

rink 1. A bounded space of ice, usually enclosed, for skating, curling, or ice hockey matches. 2. A bounded space, usually enclosed, with a smooth floor, of wood or asphalt, for roller skating.

rip To cut wood lengthwise, parallel to the grain.

riparian right The right of a landowner to use water from a river or other body of water on which his land abuts.

ripper 1. An attachment with long angled teeth that fits on the rear of a tractor or is towed by it; penetrates and loosens subsurface layers of earth to a depth of up to 3 ft (approx. 1 m). 2. A tool used for removing damaged slates on a roof; consists of a long steel blade with a notched hook at one end for withdrawing nails. 3. A towed machine, provided with teeth to loosen hard soil and soft rock.

ripping See ripsawing.

ripping bar Same as pinch bar.

ripping chisel In woodworking, a bent chisel used in clearing out mortises or seams.

ripping size The size of lumber, as it comes from the operation of ripsawing, that is required to obtain a specified finish size.

ripple figure Same as fiddleback or curl.

ripple finish A crackled or wrinkled paint finish, usually obtained by baking. Also see wrinkling.

riprap 1. Irregularly broken and random-sized large pieces of quarry rock; individual stones ranging from very large (2 to 3 cu yd, approx. 1.5 to 2.3 cu m) to small (½ cu ft, approx. 0.014 cu m); used for foundations and revetments. 2. A foundation or parapet of stones thrown together without any attempt at regular structural arrangement.

ripsaw A saw, the teeth of which have a chisel-like ripping action; used for cutting wood in the direction of the grain.

ripsawing, flat cutting, ripping Sawing lumber parallel to the grain direction.

rise 1. The height of a flight of stairs from landing to landing. 2. The height between successive treads of a stair. 3. The vertical distance such as that used to express the height of a roof slope compared to horizontal distance or run, or the vertical measurement from the face of one stair tread to the next. 4. In an arch, the vertical distance from the springing line to the highest point of the intrados. 5. Of elevators, same as travel.

rise-and-fall table A circular-saw assembly in which the table, rather than the saw, is movable.

rise and run 1. The pitch of an inclined surface or member, usually expressed as the ratio of the vertical rise to the horizontal run. 2. The slope of a building element expressed as the vertical increase in height for a selected distance in the horizontal direction.

risen molding Same as bolection molding.

riser 1. The vertical face of a stair step. 2. Any upright face, as of a seat, platform, etc. 3. A platform on the stage of a theater or concert hall on which a performer is placed. 4. A water-supply, drainage, gas, steam, or vent pipe which extends vertically, one full story or more, to service several branches or a group of fixtures. 5. An electrical cable which extends vertically, one full story or more, to distribute electrical power to electric panels on the different floors of a building. 6. A duct, which extends vertically, one full story or more, to distribute air to branch ducts on the different floors of a building. 7. A vertical supply pipe for a fire sprinkler system.

riser board In formwork, the board that forms the vertical face of a step.

riser diagram A diagram (two-dimensional, in a vertical plane) which shows the major items of electrical equipment in a building; displays, floor by floor, the feeders and major items of equipment.

riser height The vertical distance between the top surfaces of two successive treads.

riser pipe A riser, 4.

rising arch An arch having a springing line which is not horizontal.

rising damp The upward movement of moisture in a wall or other structure standing in wet soil or water.

rising hinge, rising butt hinge A door hinge having a spiral groove winding about its knuckle, or having the joints of the knuckle oblique, so that when opened, the door is lifted and clears the carpet.

rising main Same as riser, 4 or riser, 5.

risk management In the building industry, the systemized practice of avoiding potential risks, such as culpability and liability or legal entanglements.

rive To split wood along the grain, as in making shingles.

rived board, riven board A board that has been shaped by splitting it along the grain instead of sawing it.

riveling See wrinkling.

riven laths Wood laths made by splitting instead of sawing.

riven slate A slate that is cleaved along one of its parallel planes.

rivet A short pin, of a malleable metal such as iron, steel, or copper, with a head at one end; used to unite two metal plates by passing it through a hole in both plates and then hammering down the point to form a second head.

rivet centers The distance between the centers of rivets along a straight line, as along a bearing bar in a riveted grating.

riveted grating A grating composed of straight bearing bars and bent connecting bars, which are joined at their contact points by riveting.

riveted joint A connection between two members which are riveted together.

riveted truss Any truss having its main members riveted together.

rivet hole A hole through which a rivet is driven.

riveting The fastening of plates or parts by means of rivets.

riveting hammer A hammer having a long head, a flat face, and a narrow peen; used for swaging down rivets or beating sheet metal.

rivet set, rivet snap, setting punch, snap A tool for shaping the head of a rivet.

rivet snap See rivet set.

riving knife, froe, frow A tool for splitting shingles and the like.

R/L Abbr. for “random lengths.”

R lamp A reflector lamp (usually incandescent) having a thin glass envelope, the back interior side of which is aluminum-coated to serve as a light reflector; this reflecting surface is shaped so as to provide a desired beam spread.

RM On drawings, abbr. for room.

rms Abbr. for “root mean square.”

road breaker Same as concrete breaker.

road oil A heavy petroleum oil, usually one of the grades of slow-curing asphalt.

rocaille An ornament, usually asymmetrical, consisting of rock, plant, and shell forms in combination with artificial forms; widely used during the 18th century when Rococo was popular.

rock 1. Solid natural mineral material, occurring in fragments or large masses and requiring mechanical or explosive techniques for removal. 2. Stone in a mass. 3. A stone of any size.

rock asphalt Porous rock such as sandstone or limestone that has become impregnated with natural asphalt through a geological process.

rock-cut Said of a temple or tomb excavated in native rock without the aid of masonry, or with but little masonry; usually presents an architectural front with dark interior chambers, of which sections are supported by masses of stone left in the form of solid pillars.

rock dash An exterior stucco finish containing crushed rock, large pebbles, or shells that are imbedded in a stucco base; also called pebble dash or slap dash.

rock drill A machine or device for drilling a hole in rock so that it may be blasted; usually driven by compressed air, but also may be driven by electricity or by steam.

rocket tester Same as smoke rocket.

rock-faced A term descriptive of the rough face of stone as it is split at the quarry or dressed to resemble such a natural face; squared off only along the edges.

rock-faced finish Same as natural cleft finish.

rock fill A fill, 1 comprised of large, loosely placed rocks.

rock flour A very finely powdered rock material; also see silt.

rocking frame A flat mechanically powered, oscillating bed; used to compact concrete, which is in the plastic state, in precast units temporarily set on the bed.

rock lath See gypsum lath.

rock pocket A porous, mortar-deficient portion of hardened concrete; consists primarily of coarse aggregate and open voids; results from the leakage of mortar from the concrete form, separation (segregation) during placement, or insufficient consolidation.

rock rash A patchwork appliqué of oddly shaped stone slabs; used on edge as a veneer; often further embellished with cobbles or geodes.

Rockwell hardness A measure of the resistance of a material to indentation; determined by use of a machine which presses a steel ball or a spheroconical ball indentor into the material under arbitrarily fixed test conditions; expressed by the Rockwell hardness number—the higher the number, the harder the material.

Rockwell hardness number A measure of Rockwell hardness; determined by use of a machine having an indentor which can be loaded; the number is derived from the net increase in depth of impression that the indentor makes in the material as the load on the indentor is increased from a fixed load to a higher load, and then returned to the minimum load.

rock storage The storage of heat in a large mass of rocks, collected by a solar energy system during the hours of maximum solar absorption for use later, when required.

rock wool A type of mineral wool made by forming fibers from molten rock; used in thermal insulation.

rockwork 1. Quarry-faced masonry. 2. Stonework in which the surface is left irregular and rough.

Rococo A style of architecture and decoration, primarily French in origin, which represents the final phase of the Baroque around the middle of the 18th cent.; characterized by profuse, often semiabstract ornamentation and lightness of color and weight.

rod 1. In plastering, a straightedge, usually of wood, for leveling the face of a wall. 2. A solid (metal, wood, or plastic) product that is long in relation to its cross section. 3. A leveling rod.

rod bender A powered device, with movable rollers and clamps, used to bend steel reinforcing rods to shapes required in reinforced concrete.

rod cutter A bench-type device, with a guillotine-like wedge, used to cut steel reinforcing rods.

roddability The susceptibility of fresh concrete or mortar to compaction by means of a tamping rod.

rodded joint A masonry term occasionally used for a concave joint.

rodding 1. The strengthening of stone slabs or panels (usually marble) by cementing reinforcing rods into routings in the back. 2. The consolidation of mortar or concrete by the repeated insertions and withdrawals of a rod. 3. The clearing of an obstruction in a drain.

rodding eye Same as cleanout.

rode A medieval English form of rood.

rod level An accessory for use with a leveling rod or a stadia rod to assure a vertical position of the rod prior to instrument reading.

rod target A target carried on a leveling rod or a range rod and upon which sights are made in surveying.

roe figure A type of grain in wood; esp. found in tropical woods with a spiral grain which have been quarter-sawn.

roll 1. A rounded strip fastened to, and running along, the ridge of a roof. 2. In a roof covered with sheet metal, one of a number of rounded strips placed under the metal sheeting at intervals, to prevent movement of the sheets resulting from expansion and contraction. 3. Any type of rounded molding. 4. A quantity of any material wound in cylindrical form.

roll-and-fillet molding A molding of nearly circular cross section with a narrow band or fillet on its face.

roll billet molding A common Norman molding consisting of a series of billets, 1 which are cylindrical in cross section, usually staggered in alternate rows.

roll capped Said of ridge tiles having a roll along the apex.

rolled Said of metal which has been shaped, either hot or cold, by being passed between rollers.

rolled beam, rolled steel beam A metal beam fabricated of steel made in a rolling mill.

rolled glass A flat glass sheet produced by passing a stream of molten glass between two steel rollers; usually in widths up to 12 ft (3.66 m) and thicknesses from

to 1 in. (3.2 to 31.8 mm). Embossed rollers are used to produce patterned surfaces.

roll flashing A type of flashing in the form of a roll of a thin, impermeable, nonrustable material.

rolled steel beam See rolled beam.

rolled strip roofing See asphalt prepared roofing.

roller 1. See paint roller. 2. A self-propelled or towed device to compact soil.

roller coating 1. Applying a coat of paint with a paint roller. 2. A method of paint application whereby an object is coated between two rollers wet with paint.

roller-coating enamel An enamel made esp. for application on strip steel, aluminum, or other metal surfaces, using a roller-coating machine.

roller door Same as roll-up door.

roller latch A type of door latch; has a roller under spring tension instead of a beveled spring bolt; the roller engages a strike plate having a recess formed to receive it.

roller strike A strike plate which has a cylindrical roller at the point where the latch bolt of a lock makes contact with the strike plate; used to minimize friction.

rolling The use of heavy metal or stone rollers on terrazzo topping to extract excess matrix.

rolling curtain A theater stage curtain that rolls up on a horizontal drum or roll.

rolling cyclorama A cyclorama which can be rolled around a vertical drum usually by means of an electric motor.

rolling grille door A vertically moving rolling door made up of a grille which is guided in a track; has a horizontally mounted overhead rolling mechanism.

rolling shutter door Same as roll-up door.

rolling shutters See roll-up door.

roll insulation A flexible blanket-type thermal insulation in roll form; esp. used between studs or joists in frame construction.

roll joint In sheet-metal work, a joint formed by rolling the edges of adjoining sheets together and then flattening the roll.

roll molding Any convex, rounded molding, which has (wholly or in part) a cylindrical form.

rollock Same as rowlock.

roll roofing See asphalt prepared roofing.

roll-up door, rolling shutters A door made up of small horizontal interlocking metal slats which are guided in a track; the configuration coils about an overhead drum which is housed at the head of the opening; either manual or motor-driven.

rolock See rowlock.

rolock arch Same as rowlock arch.

rolok See rowlock.

Roman arch A semicircular arch. If built of stone, all units are wedge-shaped; the usual arch in Roman architecture.

Roman bath See balnea.

Roman brick Brick whose nominal dimensions are 2 in. by 4 in. by 12 in. (5 cm by 10 cm by 30 cm).

Roman bronze A copper-zinc alloy to which a small quantity of tin has been added to give it greater corrosion resistance and hardness.

Roman cement A quick-setting natural cement that can harden under water and is relatively impervious to water; made of a finely pulverized calcined argillaceous limestone that has been treated in a kiln at a temperature no higher than that necessary to drive off carbon dioxide.

Roman Classicism See Classical Revival style.

Roman house A Classical Roman dwelling, the external entrance of which opened into a quadrangular court (atrium, 1). In the ceiling of the atrium, an opening (compluvium) to the sky provided daylight and acted as an inlet for rain-water, which was collected in a pool (impluvium) sunk in the floor directly below the opening.

Romanesque Revival 1. Same as Richardsonian Romanesque style. 2. A term sometimes applied to the early works of James Renwick (1818–1895) and Richard Upjohn (1802–1878) using elements of the Romanesque style.

Romanesque style An architectural style emerging in Western Europe primarily in the 11th century and lasting until the advent of Gothic architecture in the 12th century; based on Roman and Byzantine elements; found especially in churches and castles; usually characterized by round arches and by massive articulated walls, barrel vaults, groined vaults, ribbed vaults; semicircular arches; served as the basis for the Richardson Romanesque style and occasionally used as a synonym for it.

Roman mosaic A pavement that is tessellated.

Roman order 1. A seldom-used term for the

composite order. 2. Same as arch order, 1.

Roman Revival See Classic Revival.

Roman theater An open-air theater constructed by the ancient Romans; sometimes built on a hillside, but more often on level ground— usually with a richly decorated outer façade, with a colonnade gallery and vaulted entrances for the public. The orchestra, 2 usually was a half-circle; behind it was a stage having a richly decorated proscenium and stage background. Also see Greek theater.

Romantic style A loose term embracing a variety of modes of architecture, often including Exotic Revival, Gothic Revival, Greek Revival style, Italianate style.

Roman tile A channel-shaped, tapered, single lap, roofing tile.

rone Same as gutter, 1.

rondel See roundel.

rood A large crucifix, esp. one set above the chancel entrance.

rood altar An altar standing against the nave side of a rood screen.

rood arch The central arch in a rood screen; rarely, the arch between nave and chancel over the rood.

rood beam A horizontal beam extending across the entrance to the chancel of a church to support the rood.

rood loft A gallery or elevated platform established upon the rood screen.

rood screen An ornamental altar screen that separates the nave of a church from the chancel; intended to carry a large crucifix (rood).

rood spire A spire over the crossing, 1 of the nave and transepts.

rood stairs Stairs by which the rood loft is approached.

rood stair turret A stair turret, 2; used when a rood stair projects above the roof of the church.

rood tower A tower built over the crossing, 1 and hence approximately above the rood.

roof The top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights; provides protection against rain, snow, sunlight, extremes of temperature, and wind. For definitions and illustrations of the different types, see barrel roof, bellcast roof, bonnet roof, bowed roof, broken-pitch roof, bunker fill roof, butterfly roof, candle-snuffer roof, canopy roof, collar-beam roof, compass roof, conical roof, curb roof, deck roof, double-gable roof, double-hipped roof, double-pitched roof, dropped roof, dual-pitched roof, Dutch gambrel roof, Dutch hipped roof, Dutch roof, Dutch slice-hip roof, earth roof, English gambrel roof, flat roof, Flemish roof, flounder roof, French roof, gable-onhip roof, gable roof, gambrel roof, Gothic roof, helm roof, hip-on-gable roof, hipped-gable roof, hipped roof, hip-on-gable roof, hyperbolic paraboloid roof, Italian roof, jack roof, jerkinhead roof, kick roof, knee roof, landscaped roof, lean-to roof, mansard roof, monitor roof, M-roof, New England gambrel roof, ogee roof, open roof, pavilion roof, pent roof, pigeon roof, pitched roof, ponded roof, principal roof, purlin roof, pyramidal roof, queen-post roof, rainbow roof, ridge roof, round roof, saddle-back roof, saltbox roof, segmental roof, shed roof, ship’s bottom roof, single-pitched roof, skirt-roof, slice-hip roof, sod roof, span roof, square roof, Swedish gambrel roof, terrace roof, thatched roof, truncated roof, umbrella roof, visor roof, wagon roof, whaleback roof.

roofage Same as roofing.

roof balustrade A railing with supporting balusters on a roof, often near the eaves or surrounding a widow’s walk. (See illustration p. 828.)

roof batten Same as slate batten.

roof board One of a number of boards that cover the upper surface of rafters so as to serve as a base for the application of a roof covering, such as shingles.

roof cladding See roofing, 1.

roof comb, roof crest A wall along the ridge of a roof; used to give an appearance of additional height.

roof covering 1. All the materials laid on the roof frame; includes sheathing, the outer cladding materials, asphalt paper, etc. 2. A roof covering, 1 which is not readily flammable and does not slip from position. The following classes have these and additional properties: Class A is effective against severe fire exposure, does not carry or communicate fire, and affords a fairly high degree of fire protection to the roof-deck. Class B is effective against moderate fire exposure, does not readily carry or communicate fire, and affords a moderate degree of fire protection to the roof-deck. Class C is effective against light fire exposure, does not readily carry or communicate fire, and affords a slight degree of fire protection to the roof-deck.

roof crest See roof comb.

roof cresting See cresting.

roof-deck 1. The flat portion of a roof, used as a terrace, for sunbathing, etc.; compare with deck roof. 2. The structural material between the roof supports used as a base for the roof covering system; may be metal, concrete, wood, gypsum, or a combination of these or similar materials.

roof decking Prefabricated units, usually in the form of long structural panels, which span the roof framing system and form a roof-deck, 2.

roof dormer See dormer.

roof drain A drain designed to receive water collecting on the surface of a roof and to discharge it into a leader or a downspout.

roof drainage system On the roof (or at the roof line) of a building, a system composed of storm-water collection devices, and piping connected to these collection devices; transports the rainwater off the roof and out of the building.

roofed ingle A chimney corner.

roofer A term once used for a roof board.

roof flange A flange which fits around a pipe that penetrates a roof; used on the upper side to provide a raintight installation.

roof framing The assemblage of roof members which provide support for the roof covering.

roof gallery See widow’s walk.

roof garden A garden or restaurant, or the like, on a roof.

roof guard Same as snow guard.

roof gutter See gutter, 1.

roof hatch A hinged panel unit, providing a weathertight means of access to a roof.

roofing Any material (or any combination of materials) used as a roof covering, such as corrugated metal, sheet metal, shingles, slate, thatch, or tile; usually provides waterproofing, wind-proofing, and thermal insulation.

roofing assembly The combination of all of the elements used in constructing a roof: the roof deck, substrate or thermal barrier, insulation, vapor retarder, underlayment, interlayment, base plies, and roof covering.

roofing board In a wood-framed house, a wide board that is placed over the rafters, parallel to the ridge beam.

roofing bond A guarantee by a surety company that a roofing manufacturer will repair a roof membrane or covering under the conditions listed in the bonding contract.

roofing bracket A bracket, used on a sloping roof, which is fastened to the roof or is supported by ropes fastened over the ridge and secured to a suitable object.

roofing felt See asphalt prepared roofing.

roofing nail A short nail having a barbed or ring shank and a comparatively large flat head; may be galvanized or bright; often provided with a neoprene, lead, or plastic washer; used to secure roofing felt or shingles to a roof-deck or roof boards.

roofing paper See asphalt prepared roofing, asphalt paper, building paper.

roofing putty A heavy asphaltic material used to caulk metal roofs.

roofing sand A fine, white silica sand.

roofing slate See slate.

roofing square An area of 100 sq ft (9.3 m²) of roofing surface.

roofing system An assembly of components which provide roofing.

roofing tile A tile for roofing, often fabricated of clay or slate that has been treated in a kiln at an elevated temperature; also available in many types of materials and a variety of configurations; see clay tile, mission tile, pantile, ridge tile, Spanish tile.

roof insulation 1. A board-type product, usually of low or medium density, made of mineral fibers, cellular glass, foamed plastic, lightweight concrete, wood fiberboard, or other materials, one or both sides of which may be faced with another material; provides thermal insulation in a roofing system. 2. Lightweight concrete which is used primarily for thermal insulation over a structural roof system.

roof ladder A cat ladder.

roof light Same as skylight.

roof-light sheet A sheet of transparent material used to glaze an opening in a roof.

roof line The contour or shape of a roof.

roof live load The load exerted on a roof other than the roofing system and its supporting members; the live load on the roof.

roof pitch The slope of a roof, usually expressed as the angle of pitch in degrees or as a ratio of vertical rise to the horizontal run.

roof plate A horizontal structural member that receives and supports the lower ends of the rafters of a roof; same as top plate, 1 or wall plate.

roof pond A pond of water on a roof structure that cools a building by evaporation. Because the water increases the thermal mass of the building, it also increases the gain in solar energy, storing the absorbed energy during the day, when it is abundant, for later use.

roof principal A roof truss.

roof purlin Same as purlin.

roof saddle A saddle, 3.

roof scuttle A roof hatch.

roof sheathing The boards or sheet material, especially plywood, fastened to the roof rafters, onto which the shingle or other roof covering is laid.

roof sign A board, poster, lighting display, or the like, erected and maintained on or above the roof of a building, usually to advertise or impart information.

roof slating See slating.

roof slab A slab of reinforced concrete that serves as a flat roof.

roof space Space (generally unused) between the roof and the ceiling of the highest room.

roof structure A structure on a roof or above any part of a building, such as a cooling tower or sign support.

roof tank A water-storage tank on a roof.

roof terminal The termination of a vent pipe at the roof.

roof tie 1. A collar beam. 2. A tie beam.

roof tile See roofing tile.

rooftop The roof of a house or other building.

rooftop unit A factory-made, encased room air conditioner that is mounted atop a roof to provide cooling for the rooms below.

rooftree The ridgeboard of a roof.

roof truss A structural support for a roof.

roof valley See valley.

roof vent 1. A ventilation device for an attic or roof cavity. 2. Above a legitimate theater, one of two or more vents above the stagehouse, constructed to open automatically in case of fire, with an aggregate clear opening area of not less than 5 percent of the area of the stage.

roof ventilator A ventilator, 1 on the roof of a building, usually designed to exclude rain and snow. Also see ridge ventilator.

rookery 1. A tenement or dilapidated group of dwellings. 2. A building with many diverse occupants and rooms, such as a boardinghouse.

room In a building, a particular portion, an enclosure or division separated from other divisions by partitions.

room air conditioner, packaged air conditioner, unit air conditioner, unit cooler A factory-made encased unit which is designed to deliver conditioned air to an enclosed space without the use of ducts; usually mounted in a window or in an opening in a wall, or as a console.

room acoustics Same as acoustics, 2.

room criterion curves See RC curves.

room-door lock An inside-door lock.

room monitor See monitor.

room velocity The velocity of air in the occupied zone of an air-conditioned space, expressed in feet per second (m/s).

root That portion of a tenon in the plane of the shoulders.

root-balled Said of a growing plant that has been prepared for transplantation; the largest part of its root system (together with the soil that surrounds it) is retained in the shape of a ball. Also see balled and burlapped.

root cellar A structure, either partially or wholly below ground level, that is used to store root crops, such as potatoes and beets, at a cool temperature; also see potato barn.

rooter A heavy-duty ripper intended to remove roots of trees.

rope A strong thick line, comprised of a number of twisted or braided strands of fiber (such as hemp) or of wire (see wire rope).

rope caulk A preformed bead of tacky caulking compound; often contains twine reinforcement to facilitate handling.

rope drum The drum of a hoist, 2 on which the hoisting cable or rope is wrapped.

roped hydraulic elevator A hydraulic elevator in which the piston is connected by wire ropes (cables) to the elevator car for hoisting it; the driving mechanism includes a hydraulic cylinder, piston, sheaves (and their guides), tanks, hydraulic pump, and associated valves.

rope molding A bead or torus molding carved in imitation of a rope; also see cabling.

rope suspension equalizer A device installed on an elevator car or counterweight to equalize automatically the tensions in the hoisting wire ropes.

ropiness Hills and valleys in a paint film created by bristles in a brush when the paint is applied; usually caused by the poor flow of the paint or by brushing into a semidried film.

rosace See rosette, 1.

rose A metal plate attached to the face of a door, around the shaft for the doorknob; sometimes acts as a bearing surface for the knob.

rose bit A bit used to countersink holes in wood.

rose molding An ornament used esp. in Norman architecture, chiefly during its later and richer period.

rose nail A nail with a conical head which is hand-hammered into triangular facets.

rosette 1. A round pattern with a carved or painted conventionalized floral motif; a rosace. 2. A circular or oval decorative wood plaque used in joinery, such as one applied to a wall to receive the end of a stair rail. 3. An ornamental nailhead or screwhead.

rose window, Catherine-wheel window, marigold window, wheel window A large, circular medieval window, containing tracery disposed in a radial manner.

rosewood See bubinga, Brazilian rosewood, East Indian rosewood.

rosin, colophony A resin obtained as a residue in the distillation of crude turpentine from the sap of pine trees (gum rosin) or from an extract of the stumps and other parts of them (wood rosin).

rostral column A column, in honor of a naval triumph, ornamented with the rostra or prows of ships.

rostrum A platform, elevated area, pulpit, or the like for addressing an audience.

rot Decomposition in wood by fungi and other microorganisms; reduces its strength, density, and hardness. Also see brown rot, white rot.

rotary cutting, rotary slicing A method of cutting wood veneer in which a log is fixed in a lathe and rotated against a knife so that the veneer is peeled from the log in a continuous sheet; used to produce softwood veneer and low-grade hardwood veneer.

rotary drill A machine for opening holes in rock or earth by means of a cutting bit at the end of a metal shank; usually turned by a hydraulically or pneumatically driven motor.

rotary float, power float A motor-driven revolving disk that smooths, flattens, and compacts the surface of concrete floors or floor toppings.

rotary oil burner In an oil furnace, a burner in which atomization takes place by feeding oil to a rapidly rotating cup.

rotary spreader A mechanical device which spreads fertilizer and/or seed outwardly as it rotates.

rotary trowel Same as rotary float.

rotary veneer Wood veneer obtained by rotary cutting.

roto operator A gear-driven device, turned with a small crank handle or knob; used to open and close jalousies, awning windows, casement windows, and fanlights.

rotten knot See unsound knot.

rottenstone A soft, friable limestone; in pulverized form, used for polishing soft metal surfaces and wood.

rotunda 1. A circular building, especially one with a dome. 2. A circular hall in a large building, esp. one covered by a cupola.

rough arch Same as discharging arch; built with rectangular bricks and wedge-shaped mortar joints.

rough ashlar A block of stone, as brought from the quarry.

rough-axed brick An axed brick.

roughback 1. A side cut of stone (a slab) having one side sawn and the other rough; cut from a block fed through a gang saw. 2. In masonry, a concealed end of a stone laid as a bondstone.

rough bracket A bracket under stair steps, fastened to the supporting carriage.

rough brick arch A brick arch made up of rectangular bricks that are neither cut nor tapered to voussoir shape; the required curvature is achieved by additional mortar in the joints.

rough buck See subframe, 1.

rough carpentry In a building of wood-frame construction, that part of the framing, 2, which includes boxing and sheeting.

rough carriage A carriage, 1 which is unplaned, usually concealed from view.

roughcast Same as rock dash.

roughcast glass See rough plate glass.

rough coat A scratch coat of plaster.

rough-cut joint, flat joint, flush joint, hick joint The simplest joint in masonry; made by holding the edge of the trowel flat against the brick and cutting in any direction, so that the mortar in the joints is made smooth with the wall surface. Because this cutting action produces a small hairline crack, the joint is not always watertight.

roughened finish tile Tile whose plane surfaces are entirely broken by mechanical means, such as wire cutting or wire brushing, to provide for a more effective bond for mortar, plaster, or stucco.

rough floor A layer of boards or plywood, nailed to the floor joists, which serves as a base or subfloor for the finish floor.

rough flooring Material used for the rough floor, either sheets of plywood or rough boards (often unplaned).

rough grading Cutting and filling of earth preliminary to the final work.

rough grind The initial smoothing operation in which coarse abrasives are used to cut the projecting chips in hardened terrazzo down to a level surface.

rough ground 1. A piece of linear blocking used to fix the approximate position of a desired planar surface. 2. See ground, 1.

rough hardware In building construction, hardware meant to be concealed, such as bolts, nails, screws, spikes, and other metal fittings.

roughing-in 1. The first coat of plaster in three-coat plasterwork. 2. The rough work in any phase of construction. 3. Installing the concealed portion of a plumbing system to the point of connection for the fixtures.

roughing-out In carpentry, a preliminary shaping operation.

rough lumber Sawn lumber that has not been planed; also called undressed lumber.

rough opening An opening in a wall, or the framework of a building, into which a door-frame or window frame, subframe, or rough buck is fitted.

rough plate glass, roughcast glass Translucent, rolled sheet glass, one face of which has a slightly rimpled texture.

rough pointing In masonry, the troweling of mortar in brickwork in a rough-and-ready manner.

rough rendering The application of a coat of a plaster without smoothing the surface, which is left rough.

rough rolled glass Same as patterned glass.

rough rubble A well-bonded rubble wall.

rough sawn The wood surface that results from a gang-sawing process.

rough service lamp An incandescent lamp designed to resist failure due to impact; uses extra filament supports which result in lowered efficiency.

rough sill 1. In frame construction, the sill, 1 on which the building frame is erected. 2. The wood piece laid across the bottom of a rough opening to act as a base for a window construction.

rough string, rough stringer 1. A notched, generally unplaned, inclined board which supports the steps of a wooden stairway, usually concealed from view. 2. A carriage, 1.

rough work The rough framework of a building, including framing, boxing, and sheeting.

round 1. A wood plane for cutting grooves. 2. See round molding. 3. A cylindrical metal rod.

round arch A semicircular arch.

Round Arch style An architectural style used infrequently in the mid-19th century; characterized by arcaded round arches, primarily in masonry buildings; also see Rundbogenstil.

round barn A barn having a circular plan; see circular barn.

round billet molding Same as roll billet molding.

round church One whose plan is a circle; by extension, a church designed around a central vertical axis such as those of polygonal or Greek-cross form, though these are more accurately described as churches of the central type.

round dormer A dormer having a circular window in its face.

rounded forend See rounded front.

rounded front, (Brit.) rounded forend A lock front which is shaped to conform to the rounded edge of a double-acting door (swinging door).

rounded step See round step.

rounded tile 1. Same as Mission tile. 2. One of the tiles in a course of tiles whose lower edges are semicircular; has the appearance of a series of scallops; see imbrication.

roundel 1. A small circular panel or window; an oculus. 2. In glazing, a bull’s-eye or circular light like the bottom of a bottle. 3. A small bead molding or astragal. 4. In stage lighting, a glass or gelatin color filter used in a borderlight.

round-headed Same as round-topped.

roundhouse A house that is round in plan, with no exterior corners.

round knot A knot sawn across so that it is approximately circular.

round molding, round A fairly large molding, the section of which is circular (or nearly circular) and convex.

round notch A synonym for saddle notch.

round pediment A rounded pediment, 2 used ornamentally over a door or window.

round ridge The ridge of a roof, finished with a rounded surface.

round roof Same as rainbow roof.

round step, rounded step, round-end step A step having a bullnose.

round timber Felled trees which have not been converted to lumber.

round-topped A term descriptive of a window, door, or arch having a semicircle at its head.

round-topped roll In sheet-metal roofing, a joint which is formed over a roll, 1, 2.

round tower In early Christian architecture, esp. in Ireland, a conically capped circular tower of stone construction; used for defense.

round window See Catherine-wheel window, rose window, wheel window.

rout To groove, furrow, hollow out, or otherwise machine a wood member with a router.

router 1. A router plane. 2. A machine tool having a rapidly revolving vertical spindle and cutter; used for routing, cutting mortises, etc. 3. A chisel having a curved point; used for cleaning out grooves, mortises, etc.

router gauge A tool similar to a marking gauge, but having a narrow chisel as a cutter instead of a marking point; esp. used in inlaid work, cutting out the narrow channels in which metal or colored woods are laid.

router patch A piece of plywood or veneer having parallel sides and rounded ends; used to repair a defect in a surface.

router plane, plough, plow A plane used for cutting and smoothing grooves which have their bottoms parallel to the surface; has a handle at each end and a centrally located cutting tool.

rover Any member, as a molding, that follows the line of a curve.

row house, row dwelling 1. One of an unbroken line of houses sharing one or more sidewalls with its neighbors. A group house. 2. One of a number of similarly constructed houses in a row; usually in a housing development.

rowlock, rolok, rollock 1. A brick laid on its edge so that its end is visible. 2. One ring of a rowlock arch.

rowlock arch An arch wherein the bricks or small voussoirs are arranged in separate concentric rings.

rowlock bond Same as rat-trap bond.

rowlock cavity wall, all-rowlock wall, rolock wall, rolok wall, rowlock-back wall, rowlock wall A brick cavity wall built with all bricks laid on edge.

row spacing In timber construction, the distance between rows of bolts or similar fastenings measured from center to center of the rows.

royal 1. A cedar shingle, about 24 in. (61 cm) long and ½ in. (1.25 cm) thick at the butt. 2. In military architecture, an especially strongly-defended medieval fort.

Royal Institute of British Architects (RIBA) Founded in 1835, the RIBA has been the authoritative organization for the profession of architecture in Britain; it qualifies candidates for admission to the Institute, recognizes a number of schools of architecture, and awards prizes for outstanding work. Address: 66 Portland Place, London, W1N 4AD.

rpm Abbr. for “revolutions per minute.”

RSC Abbr. for rolled steel channel, 1.

RSJ Abbr. for “rolled steel joist.”

RT Abbr. for “raintight.”

rubbed brick A brick having a rubbed finish, 2.

rubbed finish 1. A stone finish between smooth machine finish and honed finish, obtained by mechanical rubbing. 2. A finish obtained by using an abrasive to remove surface irregularities from concrete or brick. 3. On a varnished or shellacked wood surface, a dull finish, usually produced by rubbing with a pad which is saturated with pumice and water or oil.

rubbed joint An edge joint formed by coating the contacting surfaces with glue and rubbing them together until glue no longer is expelled; subsequent clamping need not be applied.

rubbed work Work in brick, concrete, wood, or stone having a rubbed finish.

rubber 1. A highly resilient material, capable of recovering from large deformations quickly; manufactured from the juice of rubber trees as well as of other trees and plants. 2. Any of various synthetically produced materials having similar properties; an elastomer. 3. A cutter.

rubber-emulsion paint See latex paint.

rubber set See false set.

rubber silencer, bumper A resilient part, such as a rubber button, attached to the stop on a doorframe to reduce noise caused by slamming of the door.

rubber tape A tape of rubber or a rubber-like compound; used to provide electrical insulation at joints.

rubber tile A hard-wearing flooring material; composed principally of natural or synthetic rubber with a filler of clay and fibrous talc or asbestos; usually set in mastic over a wood or concrete subfloor.

rubber-tired roller A heavy self-propelled or towed vehicle which rolls on a parallel series of pneumatic tires set on one or two axles; used to compact soil.

rubbing See flatting down.

rubbing block In marble polishing, a block of sandstone with which the preliminary operation of smoothing is done by hand.

rubbing brick Same as rub brick.

rubbing down An intermediate step in finishing a painted surface; rubbing with a mild abrasive before applying the topcoat.

rubbing stone A stone for polishing or erasing the toolmarks on a stone, or on bricks for gauged work after they have been rough-shaped.

rubbing varnish See polishing varnish.

rubbish A mixture of combustible waste such as paper, cardboard cartons, wood scrap, and combustible floor sweepings; contains up to 20% by weight of restaurant or cafeteria waste but contains little or no treated papers, plastic, or rubber wastes. Also see garbage, refuse, and trash.

rubble Rough stones of irregular shapes and sizes; used in rough, uncoursed work in the construction of walls, foundations, and paving.

rubble arch See rustic arch.

rubble ashlar wall A rubble wall which has an ashlar facing.

rubble concrete 1. Concrete similar to cyclopean concrete except that small stones (such as one man can handle) are used. 2. Concrete made with rubble from demolished structures.

rubble drain See French drain.

rubble masonry Same as rubblework.

rubble stone masonry Stone masonry composed of irregularly shaped units bonded by mortar.

rubble wall A wall, either coursed or uncoursed, of rubble.

rubblework Stone masonry built of rubble.

rub brick A silicon carbide brick used to smooth and remove irregularities from hardened concrete surfaces.

rudenture Same as cabling, 2.

ruderation The process of paving with pebbles or small stones and mortar.

rudus The lower layer of mortar in the bedding of a mosaic pavement.

rule An instrument having straight edges, usually marked off in inches or centimeters and fractions thereof; used for measuring distance and for drawing straight lines.

ruled joint Same as scribed joint, 2.

rule joint A pivoted joint in which two flat strips can be turned edgewise toward or from each other, but in no other direction.

ruling pen A pen used to draw lines of even thickness; commonly consists of two blades which hold ink between them, the distance between the points being adjusted by a screw.

Rumford fireplace An efficient fireplace invented by Benjamin Thompson (1753–1814), originally of Massachusetts, who later achieved distinction as Count Rumford. His innovative fireplace design increased the efficiency of radiated heat and lessened the emitted smoke, benefits that were achieved by significantly reducing the size of the massive colonial fireplace opening and by introducing a constriction in the chimney directly above the hearth so as to increase the draft through the chimney.

rummel Same as soakaway.

run 1. In roofing, the horizontal distance from the face of a wall to the ridge of the roof. 2. In stairways, the width of a single stair tread. 3. The horizontal distance covered by a flight of steps. 4. The runway or track for a sash. 5. A small stream of paint flowing vertically on a painted object; usually occurs with enamels if an excessively thick coat is applied; also called tear. 6. That section of pipe or fitting continuing in a straight line in the direction of flow in the pipe to which it is connected.

Rundbogenstil A German architectural style of the mid-19th century; especially characterized by round arches, often with Romanesque or Italianate features; the prototype of the Round Arch style.

rung A bar, usually round in cross section, forming the step of a ladder.

runic cross See Celtic cross.

Runic knot An interlaced or twisted ornament common in Anglo-Saxon architecture.

run line A thin line of paint, applied by a lining tool run along a straightedge.

run molding A molding of plaster, and occasionally of cement or other such material, formed by passing a metal or wood template over the material while wet.

runner 1. A metal supporting member which is attached to structural steel members or concrete; used to support partitions, acoustical ceiling tile, etc. Also see main runner. 2. Same as ledger, 1.

running 1. Linked in a smooth progression, inclining to the right or the left, within a band; applied to various ornamental motifs. 2. Forming a cornice in place with a running mold.

running bond Same as stretcher bond.

running dog See Vitruvian scroll.

running ground Earth in a plastic or semi-plastic state, sand, etc., which will not stand without sheeting.

running mold, horse mold A template shaped to the configuration of a cornice and mounted on a wooden frame; used by plasterers to run a molding; travels sideways along the ceiling line to build up a desired shape as plaster is applied.

running off Applying the final coat of plaster to a molding.

running ornament, running mold Any molding ornament in which the design is continuous, in intertwined or flowing lines as in foliage, meanders, etc.

running screed A narrow strip of plaster used in place of a running rule to guide the running of a cornice or molding.

running shoe A piece of metal on a running mold to prevent wear and allow it to slide freely on the running rule and nib guide.

running slope The slope of a surface which is parallel to the direction of travel; compare with cross slope.

running tie A timber framing member that interconnects joists, rafters, and/or studs.

running trap A depressed U-shaped section of pipe in a drain; allows the free passage of fluid, but always remains full, whatever the state of the pipe, so that it forms a seal against the passage of gases.

run-of-bank gravel See bank-run gravel.

runoff The flow of rainwater away from the area on which it has fallen.

run of rafter Same as run, 1.

run-to-breakdown maintenance The replacement of machinery parts only after a machinery breakdown has occurred. Contrast with on-condition maintenance.

runout A branch pipe from a hot-water main to a convector.

runway 1. In the theater, a narrow projection of the stage, over the orchestra pit and sometimes into the aisles of an auditorium, permitting the actors to perform in close proximity to the audience. 2. A path taken by buggies of concrete on decking over an area of concrete placement.

runway barn See Yankee barn.

rupture disk A safety device, used in a system under pressure, consisting of a frangible disk which ruptures when a predetermined pressure is exceeded.

rupture member Any safety device which will rupture automatically at a predetermined pressure.

rupture modulus See modulus of rupture.

rupture strength See modulus of rupture.

Ruskinian Gothic See High Victorian Gothic.

Russo-Byzantine architecture The first phase of Russian architecture (11th to 16th century) derived from the Byzantine architecture of Greece; mainly stone churches characterized by cruciform plans and multiple bulbous domes.

rust A substance, usually in powder form, of light brownish red color, accumulating on the face of steel or iron as a result of oxidation; ultimately weakens or destroys the steel or iron on which it is allowed to form.

rustic 1. Descriptive of rough, hand-dressed building stone, intentionally laid with high relief; used in modest structures of rural character. 2. A grade of building limestone, characterized by coarse texture.

rustic arch, rubble arch An arch laid up with rough or irregular stones, the spaces between them being filled with mortar.

rustic brick A fired clay brick, often multicolored, having a rough-textured surface; used for facing work.

rusticated Said of cut stone having strongly emphasized recessed joints and smooth or roughly textured block faces; used to create an appearance of impregnability in banks, palaces, courthouses, etc. The border of each block may be rebated, chamfered, or beveled on all four sides, at top and bottom only, or on two adjacent sides; the face of the brick may be flat, pitched, or diamond-point, and if smooth may be hand- or machine-tooled.

rusticated column See banded column.

rusticating Applying a coarse texture on the face of clay bricks or stone.

rustication Same as rustic work.

rustication strip A strip of wood, or the like, which is fixed to the surface of a concrete form to produce a groove or rustication in the concrete.

rustic finish, washed finish A type of terrazzo topping in which the matrix is recessed by washing prior to setting, so as to expose the chips without destroying the bond between chip and matrix; a retarder sometimes is applied to the surface to facilitate this operation.

rustic joint In stone masonry, a deeply sunk mortar joint that has been emphasized by having the edges of the adjacent stones chamfered or recessed below the surface of the stone facing.

Rustic order Same as Tuscan order.

rustic quoin A quoin treated with sunken joints, the face of the quoins being generally roughened and raised above the general surface of the masonry.

rustic siding See drop siding.

rustic slate One of a number of slate shingles of varying thickness, yielding an irregular surface when installed.

rustic stone Any rough, broken stone suitable for rustic masonry, most commonly limestone or sandstone; usually set with the elongate dimension exposed horizontally.

Rustic style A vague term denoting an architectural mode rather than an architectural style, often applied to hunting lodges or log cabins in forested areas of the northeastern United States. Characteristics include: wall construction of logs (often peeled), saddle-notch corner joints, and rough-cut lumber; a fieldstone chimney; a moderately to steeply pitched roof covered by hand-split wood shingles, a roof overhang with exposed rafters; one or more balconies or porches with flat balusters having decorative cutouts or stickwork. Occasionally called Adirondack Rustic style or Teddy Roosevelt Rustic style.