B

Babylonian architecture In ancient Babylon, architecture characterized by: mud-brick construction; walls articulated by pilasters and recesses, sometimes faced with burnt and glazed brick; narrow rooms, mostly covered with flat timber and mud roofs; and the extensive use of bitumen in drain and pavement construction and as mortar.

back 1. The rear, reverse, unseen, more remote, or less important part of a structure, tool, or object. 2. The support for a more prominent or visible element; e.g., the back of wallboard is the surface to be plastered. 3. The top or exposed side of a slate, tile, or the like, in contrast to the bed. 4. The ridge or top of a horizontal member or structure like a joist, rafter, or roof. 5. A principal rafter. 6. The extrados or top surface of an arch, often buried in the surrounding masonry. 7. A low-grade veneer used for the back ply in plywood construction. 8. The wainscoting below the sash frame of a window, extending to the floor.

back addition The projecting rear wing of a house; an outrigger.

back arch Same as arrière-voussure.

backband A piece of millwork used around a rectangular window or door casing to cover the gap between the casing and the wall or as a decorative feature. Also called a backbend.

backbar A work surface behind (and at the same height as) a liquor or service bar; usually has cabinets under the work surface which are used for storage, for the display of bottles and glassware, or for refrigerated coolers.

back bedding See back putty.

backbend 1. Same as backband. 2. At the outer edge of a metal door or window frame, the face which returns to the wall surface.

backboard A temporary board on the outside of a scaffold.

back boxing See back lining, 1.

back-brush To repaint a surface, which has just been painted, with a return stroke.

back check In a hydraulic door closer, 1 a mechanism which slows the speed with which a door may be opened.

back choir Same as retrochoir.

back clip A special clip, 3 attached to the back of a gypsum board; the clip fits into slots in the framing that holds the gypsum board in place.

backcloth Same as backdrop.

backcoating A thin coating (such as sprayed neoprene) on the back side of a fabric to increase its durability, its resistance to the flow of air, or its heat resistance.

back counter A work surface behind the front serving counter of a restaurant, usually containing short-order cooking equipment, storage cabinets, storage shelves, etc.

back-draft damper A damper, 1 having blades which are actuated by gravity, permitting air to pass through them in one direction only.

backdrop On the theater stage, a large, taut, flat canvas, usually hung from the grid at the rear of the stage to mask the backstage area.

back edging Cutting a glazed ceramic pipe by first chipping through the glaze around the perimeter and then chipping the pipe below until it is cut through.

backerboard See gypsum backerboard.

backer strip An asphalt-coated water-repellent strip which is applied behind the joint where the vertical edges of two shingles meet.

backfill Soil which is replaced in an area that has been excavated previously.

back fillet The return of the margin of a groin, doorjamb, or window jamb when it projects beyond a wall.

backfill concrete A non-structural concrete used to prepare a surface to receive structural concrete, to fill excavated pockets in rocks, or to correct over-excavation.

backfilling, backfill 1. Rough masonry built behind a facing or between two faces. 2. Filling over the extrados of an arch. 3. Brickwork in spaces between structural timbers. Also see nogging. 4. Soil or crushed stone used to fill the space between the excavation or sheeting and the exterior of a structure, or around the foundation walls to provide means for water to drain away from a foundation.

back flap, back fold, back shutter The leaf in a window shutter that folds behind the exposed leaf of the shutter; that part of a window shutter that folds into a recess in the window casing.

backflap hinge, flap hinge A hinge having a flat plate or strap which is screwed to the face of a shutter or door.

backflow 1. The flow of water or other liquids, mixtures, or substances into the distributing pipes of a potable supply of water from any other than its intended source. Also see back siphonage. 2. Any flow in a direction opposite to the natural or intended direction of flow.

backflow connection Any arrangement of pipes, plumbing fixtures, drains, etc., in which backflow can occur.

backflow preventer A device used to prevent water (or other liquids) from being siphoned into a potable water system.

backflow valve See backwater valve.

back fold See backflap.

back form See top form.

background noise The total noise from all sources other than a particular one of interest.

back gutter A gutter installed on the uphill side of a chimney on a sloping roof; used to divert water around the chimney.

back hearth, inner hearth That part of the hearth, or floor, which is contained within the jambs of the fireplace.

backhoe An excavating machine for cutting trenches; a boom-mounted bucket moves toward the machine, cutting the ground like a hoe; then the machine turns away from the cut to permit the operator to dump the soil.

backhouse, back building 1. A privy or outhouse. 2. A structure that stands behind a building to which it is a subsidiary.

backing See carpet backing.

backing board In a suspended acoustical ceiling, a flat sheet of gypsum board to which acoustical tile is attached by adhesive or mechanical means.

backing brick A relatively low-quality brick used behind face brick or other masonry.

backing coat A coat of plaster other than the finish coat.

backing ring A backing in the form of a ring, used during the welding of piping at butt joints.

backing up In masonry, the laying of backing brick.

back jamb See back lining, 1.

backjoint In masonry, a rabbet such as that made on the inner side of a chimneypiece to receive a slip.

back land Land having no road frontage requirement. It is surrounded by land owned by others.

backlighting The illumination of an object from the rear.

back lining 1. A thin wood strip which lines a window casing, next to the wall and opposite the pulley stile, and provides a smooth surface for the working of the weighted sash; also called back boxing or a back jamb. 2. That piece of framing forming the back recess for boxing shutters.

back lintel A lintel which supports the backing of a masonry wall, as opposed to the lintel supporting the facing material.

back-mop To mop the back or underside of roofing felts with asphalt or tar when laying a built-up roof.

back mortaring Same as backplastering and pargetting, 3.

back-nailing Nailing the plies of a built-up roof to the substrate (in addition to hot mopping) to prevent slippage.

back nut 1. A threaded nut, one side of which is dished to retain a grommet; used in forming a watertight pipe joint. 2. A locking nut on the shank of a pipe fitting, tap, or valve.

back observation Same as backsight.

back-paint To paint the reverse or hidden side of an object, usually for protection against the weather.

backplastering A coat of plaster applied to the back side of lath, opposite the finished surface.

backplate A plate, usually metal or wood, which serves as a backing for a structural member.

backplate lamp holder A lamp holder, integrally mounted on a plate, which is designed for screwing to a flat surface.

back pressure Pressure developed in opposition to the flow of liquid or gas in a pipe, duct, conduit, etc.; due to friction, gravity, or some other restriction to flow of the conveyed fluid.

back-pressure valve See check valve.

back propping The placing of timbers, usually set in a diagonal or oblique position, to hold a wall in place.

back putty, bed glazing The bedding of glazing compound which is placed between the face of glass and the frame or sash containing it.

backsaw A saw having a metal strip along its back to stiffen it; has many small teeth for fine, accurate sawing, as for miters.

backset 1. The horizontal distance from the face of a lock or latch to the center of the keyhole, knob, or lock cylinder. 2. Same as setback.

back shore In raking shores, an outer member under a rider shore that temporarily supports the side of a building.

back shutter See backflap.

backsight In surveying, a sight on a previously established survey point or line.

back siphonage The flowing back of used, contaminated, or polluted water from a plumbing fixture or vessel into the pipe which feeds it; due to reduced pressure in the pipe.

back siphonage preventer See vacuum breaker.

backsplash A protective panel on the wall behind a sink or counter; an apron, 7.

backstage The entire area behind the fire wall of the stage of a theater, including the rear of the stage, storage areas, and dressing rooms.

back stay Same as brace, 1.

back-to-back house A house with a party wall at the rear as well as along the sides.

backup 1. That part of a masonry wall behind the exterior facing. 2. A compressible material used behind a sealant to reduce its depth and to support the sealant against sag or indentation. 3. Overflow in a drain or piping system, due to stoppage. 4. A condition where waste water flows back into another fixture or compartment or water line (but does not flow back into the potable water system).

backup protection In an electrical system, a type of protection initiated by a sensing device that detects a failure of a protective element (such as a circuit breaker); in that event, the next upstream protective device takes over the protective function.

backup rod A strip of plastic foam that is inserted in a joint to limit the penetration of sealant into the joint.

backup strip A piece of wood at the corner of a ceiling and side wall; serves as the mounting for the ends of the gypsum-board panels.

backup strip, lathing board A wood strip which is fixed at the corner of a partition or wall to provide a nailing surface for ends of lath.

back veneer In veneer plywood, the layer of veneer on the side of a plywood sheet which is opposite the face veneer—usually of lower quality.

back vent An individual vent for a plumbing fixture located on the downstream (sewer) side of a trap, 1 to protect the trap against siphonage.

backwater valve, backflow valve A type of check valve in a drainage pipe; reversal of flow causes the valve to close, thereby cutting off flow.

bacterial corrosion A corrosion which results from substances (e.g., ammonia or sulfuric acid) produced by the activity of certain bacteria.

badger 1. A tool used inside a pipe or culvert to remove excess mortar or deposits. 2. A badger plane.

badger plane A hand plane, the mouth of which is cut obliquely from side to side, so that it can work close up to a corner.

badigeon A filler or patching material used in masonry or wood work.

baffle 1. A plate used to control the flow of a liquid. 2. An opaque or translucent plate used to shield a light source from direct view at certain angles; a light baffle. 3. A flat deflector or obstruction designed to reduce sound transmission. 4. A plate that retards and/or changes the direction of the flow of air, air-gas mixtures, or flue gases.

bag, sack A quantity of portland cement: 94 lb in the United States, 87.5 lb in Canada, 112 lb (50.8 kg) in the United Kingdom, and 50 kg in most countries using the metric system.

bagasse A by-product of sugar cane after the juice has been extracted; used as a fuel and also as the principal component in cellulose-cane acoustical tile.

bagged brickwork Brickwork that is prepared for painting by applying a thin mixture of water and mortar to the brickwork, such as by pounding the brickwork with a burlap (Hessian) bag containing the mixture.

bag molding The application of pressure on a material during molding so that it takes the shape of a curved, rigid die. The material, contained within the die and a flexible cover, is deformed by changes of pressure within the enclosure.

bagnette A bead molding.

bagnio 1. A bathing establishment. 2. A brothel. 3. A Turkish prison.

bag plug An inflatable drain stopper; when inflated, it acts to seal a pipe; usually located at the lowest point of the piping system.

bag-rubbed joint Same as flush-cut joint.

bag trap An S-shaped trap, 1 in which the vertical inlet and outlet pipes are in alignment.

bague An annular molding encircling the shaft of a column or pillar, either half-way between the base and capital or at lesser intervals.

baguette A small, convex molding.

bahut 1. In a masonry wall or parapet, the rounded upper course. 2. A low wall surmounting a cornice to carry the roof structure.

baignoire A box in a theater in the lowest tier.

bail 1. The wall of an outer court of a feudal castle. 2. A hinged loop that is used for lifting.

bailey The open area within a castle fortification. See inner bailey and outer bailey; also see motte-and-bailey.

bajarreque A wattle-and-daub wall constructed of bagasse, which is covered with plaster mixed with clay and straw.

baked finish A surface coating that achieves the desired properties by being baked, usually at a temperature of at least 150°F (65°C).

bake house A small subsidiary structure having one or more ovens used exclusively for baking of bread and pastries; once especially found in religious communities and on plantations; usually located away from the principal dwelling to reduce the risk of setting it on fire.

bake oven An oven constructed of bricks, usually having a circular or oval dome; often located within the hearth of the principal fireplace of a colonial home, usually in a corner of the hearth and a few feet above it. Bake ovens were once an integral part of the fireplace construction; some were heated by glowing charcoal or embers that were swept out before the unbaked loaves were inserted and the iron oven door closed. Also called a beehive oven, bread oven, brick oven, or Dutch oven.

baking, stoving The use of heat on fresh paint films to speed the evaporation of thinners and to promote the reaction of binder components so as to form a hard polymeric film.

balance arm On a projected window, a side supporting arm which is constructed so that the center of gravity of the sash is not changed appreciably when opened.

balance beam, balance bar A long beam, attached to a gate (or drawbridge, etc.) so as to counterbalance the weight of the gate during opening or closing.

balanced circuit A three-wire electric circuit in which the load is the same on each side of the neutral wire.

balanced construction A plywood or sandwich-panel construction which has an odd number of plies laminated together so that the construction is identical on both sides of a plane through the center of the panel.

balanced door A door so arranged that it is held either open or closed by weights.

balanced earthwork Cut and fill work in which the amount of fill equals the amount of material excavated.

balanced failure condition The condition that exists when there is the simultaneous occurrence of a primary compression failure and a primary tension failure.

balanced ladder A ladder held in a vertical position by guides with a weight attached equal to the weight of the ladder.

balanced load 1. A load connected to an electric circuit (as a three-wire system) so that the currents taken from each side of the system are equal and the power factors are equal. 2. The load at which there is simultaneous crushing of concrete and yielding of tension steel.

balanced reinforcement An amount and distribution of steel reinforcement in a flexural reinforced concrete member such that the allowable tensile stress in the steel and the allowable compressive stress in the concrete are attained simultaneously.

balanced sash In a double-hung window, a sash which opens by being raised or lowered and whose weight is balanced with counterweights or with pretensioned springs so that little force is required to lift the sash.

balanced step, dancing step, dancing winder One of a series of winders arranged so that the width of each winder tread (at the narrow end) is almost equal to the tread width in the straight portion of the adjacent stair flight.

balance pipe A pipe connection used to equalize the pressure at two points in a piping system.

balancing A procedure for adjusting the mass distribution of a rotor so that vibration of the journals, or the forces on the bearings, are reduced or controlled.

balancing plug cock See balancing valve.

balancing valve, balancing plug cock A valve used in a pipe for controlling fluid flow; not usually used to shut off the flow.

balaneion A Greek term for a bath.

balaustre, canary wood A South American glossy wood; quite hard, heavy; yellowish brown, orange, or purplish brown in color.

BALC On drawings, abbr. for balcony.

balconet A pseudo-balcony; a low ornamental railing to a window, projecting but slightly beyond the threshold or sill.

balcony 1. A projecting platform on a building, sometimes supported from below, sometimes cantilevered; enclosed with a railing or balustrade. 2. A projecting gallery in an auditorium; a seating area over the main floor. 3. An elevated platform used in a permanent stage setting in a theater.

balcony outlet In a vertical rainwater pipe that passes through an exterior balcony, a fitting which provides an inlet for the drainage of rainwater from the balcony.

balcony rail See rail, 2.

balcony stage A balcony used as a playing area, as in the Elizabethan theater.

baldachin, baldacchino, baldachino, baldaquin, ciborium An ornamental canopy over an altar, usually supported on columns, or a similar form over a tomb or throne.

bald roof See smooth-surfaced roof.

balection molding See bolection molding.

bale house 1. See straw bale house. 2. An obsolete term for warehouse.

bale tack Same as lead tack.

balistraria In medieval battlements, a cross-shaped aperture through which crossbowmen shot arrows.

balk, baulk 1. A squared timber used in building construction. 2. A low ridge of earth that marks a boundary line.

balk tie A balk, 1 which joins the wall posts of a timber roof, preventing the walls from spreading.

ball and flower See ballflower.

ballast 1. Coarse stone, gravel, slag, etc., used as an underlayer for poured concrete. 2. A device used to provide the required starting voltage and operating current for fluorescent, mercury, or other electric-discharge lamps. 3. Class P: A ballast for a fluorescent lamp which meets the requirements of the Underwriters’ Laboratories, Inc.; includes an automatic resetting thermal protector to remove the ballast from the circuit if its temperature exceeds a specified value. 4. Same as constant-wattage ballast.

ballast factor The ratio of the luminous output of a lamp when operated on a ballast to its luminous output when operated under standardized rating conditions.

ballast noise rating A measure of the noise generated by a fluorescent lamp ballast; designated by letters from A (the quietest) through F (the noisiest).

ball-bearing hinge A hinge which is equipped with ball bearings between the hinge knuckles in order to reduce friction.

ball breaker Same as wrecking ball.

ball catch A door fastener having a contained metal ball which is under pressure from a spring; the ball engages a striking plate and keeps the door from opening until force is applied.

ball-check valve A spring-operated check valve in a piping system; when the fluid flows in one direction, pressure against a movable ball allows fluid to pass; when the direction of flow is reversed, the ball is forced against a seat, thereby stopping the flow.

ball cock A float valve with a spherical float.

balled and burlapped In landscape architecture, a method of preparing a plant or tree for transplantation; the largest part of the root system is covered with a ball of soil and then wrapped in burlap (Hessian) for protection and ease of handling when it is moved to the site where it is to be planted.

ball float A floating device, usually approx. spherical in shape, which is used to operate a ball valve.

ballflower A spherical ornament composed of three conventionalized petals enclosing a ball, usually in a hollow molding, popular in the English Decorated style.

balling up In welding, the formation of globules of molten brazing filler metal or flux as a result of failure to wet adequately the metal being welded.

ballium The court of open space within a medieval fortification; a bailey.

ball joint A joint in which one part has a ball-shaped end that is held in a spherical shell attached to the other, thereby permitting the axis of one part to be set at any angle with respect to the other.

balloon A globe or round ball, placed on the top of a pillar, pediment, pier, or the like, which serves as a crown, 1.

balloon framing, balloon frame A system of framing a wooden building; all vertical structural elements of the exterior bearing walls and partitions consist of single studs which extend the full height of the frame, from the top of the soleplate to the roof plate; all floor joists are fastened by nails to studs. Compare with braced framing.

balloon-payment loan A type of loan agreement, whether or not secured by a mortgage, in which the final payment due at maturity is much larger in amount than each of the periodic payments required during the life of the loan.

ball peen hammer A hammer having a hemispherical peen.

ball-penetration test An ASTM test method used as a measure of the consistency of concrete; a metal weight having a hemispherically shaped bottom is placed on the smooth level surface of the concrete, and the depth to which it sinks is measured.

ballroom A large social hall expressly designed for dancing, but frequently used for dining or large meetings.

ball test 1. See Kelly ball test. 2. In a drain, a test for freedom from obstruction and for circularity; a ball (less than the diameter of the drain by a specified amount) is rolled through the drain.

ball valve A valve for regulating the flow of fluids by a movable ball which fits in a spherical seat.

balnea, pl. of balneum Roman baths, usually the great public ones.

balnearium In ancient Rome, a private bathroom.

balsa, corkwood The lightest of all woods, with density of about 7 to 10 lb per cu ft (110 to 160 kg per cu m); used for the core of lightweight sandwich panels, models, etc.

balteus 1. The band in the middle of the bolster of an Ionic capital. 2. The band joining the volutes of an Ionic capital. 3. One of the passages dividing the auditorium of ancient Roman theaters and amphitheaters horizontally into upper and lower zones.

baluster, banister 1. One of a number of short vertical members, often circular in section, used to support a stair handrail or a coping. 2. (pl.) A balustrade. 3. The roll forming the side of an Ionic capital; a bolster, pulvinus.

baluster column 1. A column shaped somewhat like a baluster, with a short, massive shaft. 2. A short, thick-set column in a subordinate position, as in the windows of early Italian campanili.

baluster shaft Same as baluster column.

baluster side On an Ionic capital, the return face (having the form of a concave roll), reaching from volute to volute.

balustrade An entire railing system (as along the edge of a balcony) including a top rail and its balusters, and sometimes a bottom rail.

balustrum Same as altar rail.

bamli In the architecture of India, a court or courtyard.

banana oil See amyl acetate.

banco In Spanish architecture and its derivatives, a built-in seat.

band 1. Any horizontal flat member or molding or group of moldings projecting slightly from a wall plane and usually marking a division in the wall. Also called band molding or band course. 2. A small, flat molding, broad, but of small projection, rectangular or slightly convex in profile, used to decorate a surface either as a continuous strip or formed into various shapes. Also called fillet, list. 3. A fascia on the architrave of an entablature.

bandage A strap, band, ring, or chain placed around a structure to secure and hold its parts together, as around the springing of a dome.

band clamp A two-piece metal clamp, secured by bolts at both ends; used to hold riser pipes.

band course Same as belt course.

banded architrave In late neoclassic architecture in England, Italy, and France, an architrave, 2 interrupted at intervals by smooth projecting blocks, between which are set the molded portions of the architrave.

banded barrel vault A masonry barrel vault whose semicircular cross section is stiffened at regular intervals by arches which project beneath the vault’s surface.

banded column A column with drums that alternate in size, color, or degree of ornamentation.

banded impost In medieval architecture, an impost with horizontal moldings, the section of the molding of the arch above being similar to that of the shaft below.

banded pilaster A pilaster decorated in the manner of a banded column.

banded rustication Courses of masonry, alternating smooth ashlar with rustication, in Renaissance architecture and derivatives.

banded surround A surround (i.e., a decorative architectural element around a doorway, fireplace, or window) that is banded, usually by adjacent masonry blocks that are of two different sizes; for example, see Gibbs surround.

bandelet 1. An annulet. 2. A small flat molding.

banderol, banderole, bannerol A decorative representation of a ribbon or long scroll, often bearing an emblem or inscription.

banding 1. Wood edging for veneered doors or panels; normally used at the edge of plywood or coreboard constructions. 2. One or more decorative wood strips; decorative inlay. 3. Metal, plastic, or fiber straps to tie bundles together. 4. The strapping of the top of a timber pile to prevent its splitting while being driven.

banding plane A carpenter’s plane used to cut grooves and to inlay strings and bands in straight and circular work.

band iron A thin metal strap used as a form tie, a hanger, etc.

bandlet Same as bandelet.

band molding A band, 1.

band saw A saw consisting of an endless, toothed steel belt which runs between two wheels, one of which is machine-powered.

band shell A sound-reflective construction, usually in the open air, to direct sound from performers on a stage to an audience.

band window One of a horizontal series of three windows or more, separated only by mullions, that form a horizontal band across the façade of a building; for example, see frieze-band window. Most commonly found in buildings erected after 1900. Also called a ribbon window.

banister 1. A handrail for a staircase. 2. A baluster.

bank 1. A mass of soil rising above a digging level. 2. An establishment which receives, lends, and exchanges money and carries out other financial transactions.

bank barn A two-story barn usually built into the slope of a hill and oriented so that the ground floor is protected from the prevailing wind. An inclined driveway leads to a large sliding door on the upper floor, which contains an area set aside for threshing grain, storing grain, and storing animal feed. The level below provides housing for animals and is entered at ground level from an enclosed yard. In the United States, sometimes called a German barn, Pennsylvania barn, or Pennsylvania Dutch barn. Also see barn, forebay barn, Swiss barn, Yankee barn.

bank cubic yard (or meter) A unit to express the volume of bank material.

bank depository A safe on the exterior of a building which receives deposits after business hours.

banker The bench or table upon which bricklayers and stonemasons prepare and shape their material.

banker-mark In medieval construction, a mark cut in a dressed stone to identify the stonecutter.

banker mason Same as master mason.

bank gravel See bank-run gravel.

bank house See German Colonial architecture.

bank material Soil or rock in place before excavation or blasting.

bank measure 1. A measure of the volume of a mass of soil or rock, before excavation, in its natural position. 2. The measurement of earth material in situ (i.e., in its original place in the ground).

bank meters The number of cubic meters of material in its original place in the ground.

bank-run gravel, bank gravel, run-of-bank gravel Aggregate taken directly from natural deposits; contains both large and small stones.

bank sand Compared to lake sand, a sand having sharp edges so that when used in plastering it results in a better bond and greater plaster strength.

bank yards The number of cubic yards of material in its original place in the ground.

bannerol See banderol.

banner vane A weather vane having the shape of a banner; balanced by a weight on the other side of the banner.

banquet hall A room used for dining, social gatherings, or meetings accommodating large numbers of people.

banquette 1. A long, upholstered seat built in against a wall. 2. A raised, narrow walk along a roadway. 3. A term once used in some parts of the American South for a sidewalk. 5. Same as barbette.

banquette cottage In New Orleans in the early 19th century, a small town house located flush against a sidewalk.

baptistery A building or part of one wherein the sacrament of baptism is administered.

bar 1. One of the thin strips of wood or metal forming the several divisions of a sash or a wood panel door, employed to receive the glass. 2. A solid metal product having a square, rectangular, or other simple symmetrical cross-sectional shape and a length much greater than its width. 3. A counter over which liquor and other beverages are served; may be equipped with a footrail if stools are not provided. 4. A steel reinforcing bar. 5. A unit of pressure equal to 10⁵ pascals, 10⁵ newtons per square meter, or 10⁶ dynes per square centimeter. 6. One of a number of thin strips of wood or metal forming the several divisions of a window sash or a wood-paneled door. 7. Same as iron mantel, 3.

baraban In early Russian architecture, same as drum, 2.

barbacan See barbican.

barabara 1. A sod house. 2. A partially underground dwelling.

barb bolt, rag bolt A bolt having jagged edges to prevent its being withdrawn from the object into which it is driven.

barbed Said of a shank (e.g., that of a nail) which has been provided with repetitive ridges or indentations which may be shallow or deep, oblique or crosswise, diagonal or perpendicular.

barbed wire, barbwire Two or more wires twisted together with sharp hooks or points (or a single wire furnished with barbs); used for fences.

bar bender Same as hickey.

bar bending In reinforced concrete construction, the process of bending reinforcing bars to various shapes.

barbette A raised platform in a medieval fort that served as a mounting surface for a weapon to fire over a parapet at the enemy.

barbican, barbacan The outer defense work of a castle or town, frequently a watchtower at the gate.

barbwire See barbed wire.

bar chair See bar support.

bar clamp A clamping device used in carpentry; consists of a long bar with adjustable clamping jaws.

bare Descriptive of a piece of material which is smaller than the specified dimensions; scant.

bare conductor An electrical conductor having no covering or electrical insulation.

barefaced tenon, bareface tenon A tenon having a shoulder cut on one side only.

bargain and sale deed A deed in which the grantor represents that he has some interest in the property being conveyed, without warranting that he has a clear unencumbered title. Such a deed often includes a warranty that the grantor did not encumber the property or convey away any part of the title during his period of ownership. Also see quitclaim deed; warranty deed.

barge arch A low arch of a bridge under which barges are transported.

bargeboard, gableboard, vergeboard A board which hangs from the projecting end of a roof, covering the gables; often elaborately carved and ornamented in the Middle Ages.

barge couple 1. One of the two rafters that support that part of a gable roof which projects beyond the gable wall. 2. One of the rafters (under the barge course) which serve as grounds for the barge boards and carry the plastering or boarding of the soffits; also called a barge rafter.

barge course 1. The coping of a wall, formed by a course of bricks set on edge. 2. In a tiled roof, the part of the tiling which projects beyond the principal rafters (bargeboards) where there is a gable.

barge rafter Same as barge couple, 2.

barge spike, boat spike A long spike, square in cross section, used in timber construction.

barge stone One of the stones, generally projecting, which form the sloping top of a gable built of masonry.

bar iron A strong, malleable iron, available in the form of bars, which can be beaten into various shapes by blacksmiths to form tools, horseshoes, hardware, and highly decorative ironwork. See wrought iron.

barite A mineral used in concrete as an aggregate, esp. for the construction of high-density radiation shielding; also called barium sulfate.

barium plaster A special mill-mixed gypsum plaster containing barium salts; used to plaster walls of x-ray rooms.

barium sulfate See barite.

bar joist An open-web flat-trussed structural member used to support a floor or roof structure.

bark The protective outer layer of a tree, composed of inner, conductive cells and outer corklike tissue.

bark house A dwelling once used by certain Indian tribes in America; usually made of a framework of wood poles, lashed together, and covered with overlapping slabs of bark.

bark mill A small building that was once used for processing bark used in dyeing and tanning.

bark pocket, inbark, ingrown bark A small quantity of bark, nearly or entirely enclosed in wood.

barley-sugar column (Brit.) A spiral column.

bar mat A network of steel reinforcing bars assembled in two or more layers and welded or tied together.

barmkin In the Middle Ages, the battlement of a fortified tower in Scotland and northern England.

bar molding A rabbeted molding applied to the edge of a counter or bar to serve as a nosing.

barn A farm building, most often rectangular (but occasionally circular or polygonal), for housing farm animals, storing farm equipment, threshing grain, and storing grain, hay, and other agricultural produce. Barn construction usually depends on such factors as the local climate and traditions, building materials available, the skills and time required for construction, and the cost. For some examples, see bank barn, basement barn, circular barn, connected barn, Connecticut barn, crib barn, double barn, Dutch barn, English barn, forebay barn, four-crib barn, German barn, hex barn, New England connected barn, octagon barn, Pennsylvania barn, Pennsylvania Dutch barn, potato barn, raised barn, round barn, side-hill barn, Sweitzer barn, Swiss barn, three-bay barn, tobacco barn, Yankee barn.

barn-door hanger A hanger for an exterior sliding door; consists of a frame which moves along a horizontal track, supported by rollers.

barn-door stay A small wheel which rolls along a horizontal track and guides the movement of a barn door.

barn raising In the United States before the 20th century, a cooperative effort in which the elements of the framework for a large barn were assembled and lifted into place. The walls were supported by sections of a massive timber framework, called bent frames. First, the cellar was dug and the barn floor constructed. Next, the bent frames were assembled on the ground adjacent to the barn by fitting the various components of the frame together and fastening them with wood pegs driven into previously drilled holes. Finally, at the appropriate locations, each bent frame was raised into an upright position by the use of long poles with steel points (barn pikes) and then interconnected with other bent frames. See the illustration under bent frame showing how the bent frames were raised, an action that required considerable manpower and therefore the assistance of neighbors; this collaborative effort is also known as a barn raising or raising bee.

barometric damper An automatic adjustable device for regulating the draft through a fuel-burning appliance, thereby making operation of the appliance nearly independent of the chimney draft over its normal range of operation.

barometric draft regulator A damper usually installed in the breeching between a boiler and chimney; permits air to enter the breeching automatically as required, to maintain a constant overfire draft in the combustion chamber.

barometric pressure See atmospheric pressure.

Baroque A European style of architecture and decoration which developed in the 17th cent. in Italy from late Renaissance and Mannerist forms, and culminated in the churches, monasteries, and palaces of southern Germany and Austria in the early 18th cent. It is characterized by interpenetration of oval spaces, curved surfaces, and conspicuous use of decoration, sculpture, and color. Its late phase is called Rococo. The style prevailing in the restrained architectural climate of England and France can be called Baroque classicism.

bar post One of the posts driven into the ground to form the sides of a field gate.

barracks Permanent or temporary housing for soldiers or, less often, groups of workmen.

bar-rail molding Same as bar molding.

barreaux Wood bars forming a latticework between wall posts in French Vernacular architecture of Louisiana and environs; provided a structural support for infilling set between structural timbers.

barred-and-braced gate A gate with a diagonal brace to reinforce the horizontal timbers.

barred gate A gate with one or more horizontal timber rails.

barrel 1. A weight measure for portland cement in the US, corresponding to 376 pounds net; this measure is now obsolete. 2. (US) A vessel which holds 31½ gal of liquid. 3. That portion of a pipe having a constant bore and wall thickness.

barrel arch An arch formed of a curved solid plate or slab, as contrasted with one formed with individual curved members or ribs.

barrel bolt, tower bolt A door bolt which moves in a cylindrical casing; not driven by a key.

barrel ceiling A ceiling of semicylindrical shape.

barrel drain Any drain which is cylindrical in shape.

barrel fitting A short length of threaded connecting pipe, as a nipple.

barreling, tumbling The application of paint to small articles by tumbling them in a barrel containing paint.

barrel nipple A barrel fitting threaded at each end.

barrel roof, barrel shell roof 1. A roof of semicylindrical section; capable of spanning long distances parallel to the axis of the cylinder. 2. A barrel vault.

barrel shell A reinforced concrete scalloped roof that spans a structure in one direction as folded-plate construction, and in the other direction as a barrel vault.

barrel vault, barrel roof, cradle vault, tunnel vault, wagonhead vault, wagon vault A masonry vault of plain, semicircular cross section, supported by parallel walls or arcades and adapted to longitudinal areas.

barricade An obstruction to deter the passage of persons or vehicles.

barrier 1. Same as barricade. 2. According to the Architectural Barriers Act, any obstacle to the accessibility of a building by disabled people.

barrier fort 1. One of a number of mutually-supporting medieval forts which protect a large area of the countryside. 2. A fort that can withstand a limited siege.

barrier-free Said of a building or facility that is accessible to the handicapped.

barrier-free environment As specified in the Americans with Disabilities Act, an environment containing no barriers, 2.

barrow 1. A wheelbarrow. 2. An elongated artificial mound protecting a prehistoric chamber tomb or passage grave.

barrow area An area that serves as a source of fill, providing soil which is used to raise an existing grade elsewhere.

barrow hole A hole that is left open in an exterior wall during a building’s construction to provide access to the interior. Upon completion of construction, the hole is closed up.

barrow run A temporary pathway of wood planks or sheets to provide a smooth access for wheeled materials-handling carriers on a building site.

Barryesque A variation of the Italianate style introduced by Sir Charles Barry, an outstanding Victorian architect who designed the Houses of Parliament.

bar sash lift A type of handle, attached to the bottom rail of a sash, for raising or lowering it.

bar schedule A tabulation of the reinforcement used in reinforced concrete, showing the number, shape, size, and dimensions of each element that is required.

bar screen A coarse screening device used to separate large pieces of stone from smaller pieces, which fall through the spaces between equally spaced bars, 2.

bar size section A hot-rolled angle, channel, tee, or zee having its greatest cross-sectional dimension less than 3 in. (7.6 cm).

bar spacing The center-to-center distance (perpendicular to the longitudinal axis) between parallel reinforcing bars.

barstone Before the invention of grates in a fireplace, one of two upright stones placed in the fireplace to receive the ends of a metal bar on which meat was roasted.

bar strainer A screening device consisting of a bar or a number of parallel bars; used to prevent objects from entering a drain; also see bar screen.

bar support, bar chair A device used to support and/or hold steel reinforcing bars in proper position before or during the placement of concrete.

bartisan Same as bartizan.

bartizan On a fortified wall, a small overhanging structure with lookout holes and loops, often at a corner or near an entrance gateway.

bar tracery A pattern formed by interlocking bars of stone within the arch of a Gothic window.

bar-type grating An open grid assembly of metal bars in which the bearing bars (running in one direction) are spaced by rigid attachment to cross bars.

barway A gate opened by moving a bar or bars.

barytes Same as barite.

basalt A dark, fine-grained, igneous rock used extensively for paving stones, but rarely for building stone.

bascule A structure that moves about a horizontal axis, as a seesaw, with a counterbalance at one end.

base 1. The lowest (and often widest) visible part of a building, often distinctively treated. A base is distinguished from a foundation or footing in being visible rather than buried. 2. A low, thickened section of a wall; a wall base. Also see socle. 3. Lower part of a column or pier, wider than the shaft, and resting on a plinth, pedestal, podium, or stylobate. Also see Asiatic base, Attic base. 4. A baseboard; skirting. 5. A preparation for a finished surface, as for flooring, stucco, paint, etc.; a surface to which the base coat of plaster is applied. Also see backing, ground. 6. In paint, either the medium or the main chemical ingredient. 7. In asphaltic or portland cement concrete paving, the prepared bottom course of crushed stone or gravel upon which subsequent courses are laid; serves to distribute localized wheel loads over a larger subbase and hence to improve load-bearing capacity. 8. The lowest point of any vertical pipe.

base anchor The metal piece attached to the base of a doorframe for the purpose of securing the frame to the floor; either fixed or adjustable.

basebead Same as base screed.

base bid The amount of money stated in the bid as the sum for which the bidder offers to perform the work, 1 not including that work for which alternate bids are also submitted.

base bid specifications The specifications listing or describing only those materials, equipment, and methods of construction upon which the base bid must be predicated, exclusive of any alternate bids. Also see specifications and closed specifications.

base block 1. A block of any material, generally with little or no ornament, forming the lowest member of a base, or itself fulfilling the functions of a base, as a member applied to the foot of a door or to window trim. 2. A rectangular block at the base of a casing or column which the baseboard abuts; usually slightly thicker than either the casing or baseboard. 3. A skirting block.

baseboard, mopboard, scrubboard, skirting board, washboard A flat projection from an interior wall or partition at the floor, covering the joint between the floor and wall and protecting the wall from kicking, mopping, etc. It may be plain or molded; a base, 4.

baseboard heater A heating system in which the heating elements are installed in panels along the baseboard of a wall.

baseboard raceway A channel having a removable cover, sometimes installed along a baseboard in an existing building to house wiring. Removal of the cover provides easy access to the wiring.

baseboard radiator unit A heating unit which is designed to replace a baseboard along a wall; water or steam flows directly behind the face of the unit (or heat is supplied to the face by electric heating elements directly behind it); heat from the face is transmitted to the room. In the finned-tube type, the fins are heated by water or steam flowing through the tube; this heat is delivered to the room through slots in the face of the unit.

base building A building for general usage which has not yet been adapted to meet the special requirements of a specific tenant.

base cap See base molding.

base clip Same as base anchor.

base coat 1. All plaster applied before the finish coat; may be a single coat or a scratch coat and a brown coat. 2. The first coat applied to a surface, as paint; a prime coat. 3. An initial coat applied to a wood surface before staining or otherwise finishing it.

base coat floating The spreading, compacting, and smoothing of the base coat of plaster so that it is finished to a reasonably true plane.

base course 1. A foundation or footing course, as the lowest course in a masonry wall. 2. A layer of selected material of planned thickness, constructed on the subgrade or subbase for the purpose of serving one or more functions such as distributing load, providing drainage, minimizing frost action, etc. 3. The lowest layer in a pavement construction.

base-court, basse-cour 1. A yard or ward behind the outer bailey of a castle. 2. On a farm, a service yard often reserved for fowl. 3. A lesser or service courtyard in any building. 4. (Brit.) A lower court of law.

base elbow A cast-iron pipe elbow having a baseplate or flange cast on it, by which it is supported.

base exchange Same as cation-exchange softening of water.

base flashing 1. The flashing provided by upturned edges of a watertight membrane on a roof. 2. Any metal or composition flashing at the joint between a roofing surface and a vertical surface, such as a wall or parapet.

base line A surveyed line which has been established with more than usual care, and to which surveys are referred for coordination and correlation.

base map In urban planning, a map indicating the significant existing physical features of an area, i.e., streets, rivers, parks, railroads, etc., and serving as a foundation for all subsequent mapping.

basement 1. Usually the lowest story of a building, either partly or entirely below grade. Also see cellar, American basement. 2. The lower part of the wall or walls of any building. 3. The substructure of a column or arch. Frequently, the applicable building code specifies that only one floor level shall be classified as a basement. Also see American basement, English basement, French basement, raised basement, walk-out basement.

basement barn A term sometimes used for bank barn.

basement house A house whose rooms are mainly located above ground level but whose entrance, from the exterior, is at ground level or one floor above.

basement soil See subgrade, 1.

basement stair A stairway connecting the basement or cellar with the level of the living area.

basement wall A foundation wall which encloses a usable area under a building.

basement window A window in the basement of a residence.

base metal The metal to be welded or soldered (as distinguished from filler metal which is deposited during the joining process).

base molding Molding used to trim the upper edge of interior baseboard; a base cap.

baseplate 1. A metal plate used to distribute a nonuniform load. 2. A metal plate on which a column rests. 3. A metal plate used as a foundation for heavy machinery; a bed plate.

base ply In roofing: the layer of felt secured to the deck over which a built-up roof is applied.

base screed A metal screed having expanded or short perforated flanges; acts as a dividing strip between plaster and cement; provides a ground (guide) to indicate proper thickness of plaster and cement.

base sheet Saturated and/or coated felt sheeting which is laid as the first ply in a built-up roofing membrane.

base shoe, base shoe molding, floor molding, shoe molding, carpet strip A molding used next to the floor on interior baseboard.

base shoe corner A molding piece or block applied in the corner of a room to eliminate the need for mitering the base shoe.

base table A base molding, 2.

base tee A pipe tee with a connected baseplate for supporting it.

base temperature The reference temperature given in the definition for degree-day.

base tile The lowest course of tiles in a tiled wall.

Basic Building Code A model code that has been widely used in the US, particularly in the northeastern and midwestern states.

basic creep In concrete construction, creep occurring without the migration of moisture to (or from) the concrete.

basic insulation level (BIL) The insulation capability of an item of electrical equipment (e.g., a transformer) to withstand specified voltage surges.

basic services The services performed by an architect during the following five phases of a project: schematic design; design development; construction documents; bidding or negotiation; and contract administration.

basic wind speed The wind speed that is used in determining wind load on a structure before other factors (such as height above the ground and the effects of shielding) are taken into account.

basil Same as bezel.

basilica 1. A Roman hall of justice, typically with a high central space lit by a clerestory and lower aisles all around it, and with apses or exedrae for the seats of the judges. 2. The form of the early Christian church, a central high nave with clerestory, lower aisles along the sides only, with a semicircular apse at the end. Often preceded by a vestibule (narthex) and atrium. In larger basilicas, there are often transepts, and sometimes five aisles.

basin 1. A somewhat shallow vessel for holding water (or the like). 2. A shallow tank or natural or artificial depression containing water.

basin fittings The trim, 3 on a water basin that usually includes one or more faucets, a trap, an overflow pipe, and adapters.

basket See bell, 1.

basket capital A capital having a shape similar to an inverted bell that is ornamented with surface work similar to basket weave.

basket-handle arch, basket arch A flattened arch whose ellipse-like shape is determined by three arcs that are interconnected, each arc being drawn from a different center of curvature; also called a semielliptical arch or an elliptical arch.

basket newel A newel at one end of a handrail at the bottom of a flight of stairs; has the overall shape of a tall cylindrical basket.

basket weave A checkerboard pattern of bricks, flat or on edge.

basket-weave bond A brick bond arrangement having a checkerboard pattern.

bas-relief, basso-relievo, basso-rilievo A carving, embossing, or casting moderately protruded from the background plane; low relief.

basse-cour See base-court.

basso-rilievo, basso-relievo See bas-relief.

basswood, American linden A cream-colored, fine-textured, moderately low-density wood of North America; used extensively for plywood, lumber core, and trim.

bas-taille Same as bas-relief.

bastard A nonstandard item; one of irregular or abnormal size or shape or of inferior quality.

bastard ashlar, bastard masonry 1. Stone, in thin blocks, used to face a brick or rubble wall; square-hewn and laid to resemble ashlar. 2. Ashlar stones which are only roughly dressed at the quarry.

bastard bond Same as header bond.

bastard file One of four principal classifications of files which are graded according to coarseness (coarse, bastard, second, smooth).

bastard granite A quarry term for gneissic granites; not considered a true granite; used in wall construction.

bastard joint Same as blind joint.

bastard masonry See bastard ashlar.

bastard pointing See bastard tuck pointing.

bastard-sawn See plain-sawn.

bastard spruce Same as Douglas fir.

bastard stucco Plaster applied in three coats: a scratch, a brown, and a finish coat.

bastard tuck pointing, bastard pointing An imitation tuck pointing in which the external face is parallel to the wall, but projects slightly and casts a shadow.

bastel house, bastille house, bastle house A partly fortified house whose lowest story usually is vaulted.

bastide 1. A medieval settlement built for defense purposes and generally laid out with a geometric plan, esp. in France. 2. A small rural dwelling in southern France.

bastille, bastile 1. A fortification or castle, frequently used as a prison. 2. A tower or bulwark in the fortifications of a town.

bastille house A bastel house.

bastion A defense work, round, rectangular, or polygonal in plan, projecting from the outer wall of a fortification, principally to defend the adjacent perimeter.

bastle house See bastel house.

baston, baton, batoon 1. A torus. 2. See batten.

bat 1. A piece of brick with one undamaged end; also called a “brickbat.” 2. A unit of batt insulation. 3. A piece of wood used as a brace. 4. A batten.

Bataan mahogany Same as tanguile.

bat bolt A bolt barbed or jagged at the butt, or tang, to give it a firmer hold.

batch 1. A quantity of concrete or mortar mixed at one time. 2. A quantity of adhesive mixed at one time.

batch box A container of known volume used to measure and mix the constituents of a batch of concrete, plaster, or mortar, to ensure proper proportions.

batched water The mixing water added to a concrete or mortar mixture before or during the initial stages of mixing.

batcher A device for measuring ingredients for a batch of concrete.

batching Weighing or measuring the volume of the ingredients of a batch of concrete or mortar, and then introducing these ingredients into a mixer.

batch mixer A machine that mixes grout, mortar, or concrete in batches in contrast to one that mixes continuously.

batch plant An operating installation of equipment including batchers and mixers as required for batching or for batching and mixing concrete materials; also called a mixing plant when mixing equipment is included.

batement light A window with its lower edge cut diagonally rather than horizontally so as to fit an arch or rake below; esp. used in perpendicular tracery.

bath 1. An open tub used as a fixture for bathing. 2. The room containing the bathtub. 3. (pl.) The Roman public bathing establishments, consisting of hot, warm, and cool plunges, sweat rooms, athletic and other facilities; balnea, thermae.

bathhouse 1. A building equipped with bathing facilities. 2. A small structure containing dressing rooms or lockers for bathers, as at the seaside.

bathroom A room containing a water closet, a lavatory, and a bathtub and/or shower.

bathroom cabinet Same as medicine cabinet.

bath trap The P-trap in the waste line of a bathtub.

bathtub A tub for bathing, usually a fixed plumbing installation designed for one person.

bat insulation Same as batt insulation.

baton A batten.

bâtons rompus Short, straight pieces of convex molding, as those forming Norman or Romanesque chevrons and zigzags.

batoon A batten.

batt A unit of batt insulation.

batted work, broad tooled A hand-dressed stone surface scored from top to bottom in narrow parallel strokes, (usually 8 to 10 per inch) (20 to 25 per centimeter), by use of a batting tool. The strokes may be vertical or oblique.

batten 1. A narrow strip of wood applied to cover a joint along the edges of two parallel boards in the same plane. 2. A strip of wood fastened across two or more parallel boards to hold them together; also called a cross batten. 3. A flat strip of wood attached to a wall as a base for lathing, plastering, etc.; also called a furring strip. 4. In roofing, a wood strip applied over boards or roof structural members; used as a base for the attachment of slate, wood, or clay-tile shingles. 5. See board and batten. 6. A board usually 2 in. (5 cm) to 4 in. (10 cm) thick and usually used as a lathing support or in flooring. 7. A steel strip used to secure metal flooring on a fire escape. 8. On a theater stage, a strip of wood to frame, stiffen, or reinforce a flat, or to fasten several flats together. 9. On a theater stage, length of hollow metal of round, square, or rectangular cross section used in connection with stage rigging to hang scenery or lighting equipment, such as a pipe batten or lighting batten.

battenboard See coreboard.

battened column A column consisting of two longitudinal shafts, rigidly connected to each other by batten plates.

battened door A wood door without stiles which is constructed of vertical boards held together by horizontal battens, 2, on the back side. Also called a batten door, ledged door, and unframed door.

battened shutters Solid, unframed, window shutters held together by horizontal battens, 2; similar in construction to small battened doors.

battened wall, strapped wall A wall to which battens have been affixed.

battening Narrow battens or wood strips attached to a wall for the purpose of receiving lath and plaster.

batten plate, stay plate A steel plate used to join two parallel components (such as flanges or angles) of a built-up structural column, girder, or strut; designed to transmit shear between the two components.

batten roll, conical roll In metal roofing, a roll joint formed over a triangular-shaped wood piece.

batten seam A seam in metal roofing which is formed around a wood strip.

batter To incline from the vertical. A wall is said to batter when it recedes as it rises.

batter board 1. One of a pair of horizontal boards which are nailed (at right angles to each other) to three posts set beyond the corners of a building excavation; used to indicate a desired location; strings, fastened to these boards, are used to indicate the exact corner of a building. 2. One of the boards set across a pipe trench to carry a cord or wire grade line.

batter brace, batter post A diagonal brace which reinforces one end of a truss.

battered A term descriptive of a surface that is inclined or tilted with respect to the vertical; for example, a battered wall.

battered wall A wall having a batter.

batter level A device for measuring the inclination of a slope.

batter pile, brace pile, spur pile A pile driven at an inclination to the vertical to provide resistance to horizontal forces.

batter post 1. See batter brace. 2. A post at one side of a gateway or at a corner of a building for protection against vehicles.

batter rule In constructing a battered wall, a device for regulating the inclination.

batter stick A tapered board which is hung vertically; used to test the batter of a wall surface.

battery 1. A combination of two or more electric cells capable of storing and supplying direct current by electrochemical means. 2. Any group of two or more similar adjacent plumbing fixtures which discharge into a common horizontal waste or soil branch.

batting Same as batted work.

batting tool A mason’s chisel usually 3 to 4½ in. (7.6 to 11.4 cm) wide, used to dress stone to a striated surface. See batted work.

batt insulation A flexible blanket-type thermal insulation, commonly used as insulation between studs or joists in frame construction; also used as an acoustical material or a component in sound-insulating construction. Usually made from rock, slag, or glass fibers. Sometimes has a vapor barrier on one side or is entirely enclosed in paper with a vapor barrier on one side. Nominally 16 (40.6 cm) or 24 in. (61 cm) wide, and approx. 1 to 6 in. (2.5 to 15 cm) thick.

battlement, embattlement 1. A fortified parapet with alternate solid parts and openings, termed respectively “merlons” and “embrasures” or “crenels” (hence crenelation). Generally for defense, but employed also as a decorative motif. 2. A roof or platform serving as battle post. 3. A decorative motif having the general shape of a battlement.

Bauhaus A school of design established in Weimar, Germany, by Walter Gropius in 1919. The term became virtually synonymous with modern teaching methods in architecture and the applied arts, and with a functional aesthetic for the industrial age; often characterized by emphasis on functional design, the use of a repetitive interval between members of the framework of a building, and the maintenance of purely geometric forms. Often, major building components such as bays, doors, and windows are placed to coincide with this repetitive interval, although the building itself may be asymmetrical.

baulk Same as balk.

baulk-tie See balk-tie.

bawn 1. A fortified enclosure, often of mud or stone, surrounding a farmyard or castle; esp. in Ireland. 2. A fortified house (especially during the 17th century) with massive walls, designed to serve as a haven of refuge in the event of an enemy attack; also see garrison house.

bay 1. Within a structure, a regularly repeated spatial element defined by beams or ribs and their supports. 2. A protruded structure with a bay window. 3. The free or light space between sash bars. 4. In landscape architecture, a recess or alcove formed by plants in a design. 5. In plastering, the distance between screeds employed for working the floating of plaster.

bayle The open space contained between the first and second walls of a fortified castle; a bailey, 1.

bay leaf A stylized laurel leaf used in the form of a garland to decorate torus moldings.

bayonet holder, bayonet socket A type of lamp holder which provides mechanical support and electric connections for an electric light bulb; esp. used in Great Britain.

bayonet saw Same as saber saw.

bay stall (Brit.) A built-in window seat.

bayt 1. A Muslim dwelling, generally for one family, e.g., a tent or house. 2. In the early Muslim palace complex, a separate dwelling unit.

bay window A window that protrudes from a wall, usually bowed, canted, polygonal, segmental, semicircular, or square-sided in plan; typically one story in height, although sometimes higher; occasionally corbeled out from the face of the wall, as an oriel; also see angled bay window, bow window, cant window.

bazaar A marketplace where goods are exposed for sale; esp. in the East, consisting either of small shops or stalls in a narrow street or series of streets, or of a certain section of town under one roof and divided into narrow passageways.

b/b_o Symbol for course-aggregate factor.

bbl Abbr. for “barrel.”

BC Abbr. for “building code.”

BCM Abbr. for “broken cubic meter.”

BCY Abbr. for “broken cubic yard.”

bd. In the lumber industry, abbr. for “board.”

bd. ft. In the lumber industry, abbr. for “board foot.”

bdl In the lumber industry, abbr. for “bundle.”

beacon house Same as lighthouse.

bead 1. A bead molding. 2. A narrow wood strip, molded on one edge, against which a door or window sash closes; a stop bead. 3. A strip of metal or wood used around the periphery of a pane of glass to secure it in a frame, ventilator, or sash; a stop. 4. A pearl-shaped carved decoration on moldings or other ornaments, usually in series, or in conjunction with other shapes; a beading. Also see bead and reel molding. 5. A molding decorated with beading; an astragal, 1 or chaplet. 6. Used in combination with other terms to describe the function or position of a beaded molding, such as quirk bead, angle bead, corner bead, etc. 7. The act of carving or running a bead; beading. 8. In metal roofing or flashing, the shape formed by folding a narrow strip of the edge flat or rolling it into a tube in order to stiffen or fasten the metal. 9. A factory-formed light-gauge metal strip having one or two expanded or short perforated flanges and variously shaped noses; used at the perimeter of plastered surface as a casing bead or plaster stop, and at corners to reinforce the edge. 10. A hardened drop of excess paint or varnish. 11. A narrow, convex strip of sealant, such as caulking or glazing compound. 12. A weld bead.

bead, butt and square Similar to bead and butt but having the panels flush on the beaded face only, and showing square reveals on the other.

bead and butt, bead butt, bead butt work Framed work in which the panel is flush with the framing and has a bead run on two edges in the direction of the grain; the ends are left plain.

bead and flush panel See beadflush panel.

bead and quirk See quirk bead.

bead and reel, reel and bead A semiround convex molding decorated with a pattern of disks alternating with round or elongated beads.

bead butt, bead butt work See bead and butt.

beaded clapboard See clapboard.

beadflush panel, bead-and-flush panel A panel which is flush with the surrounding framing and finished with a flush bead on all edges of the panel.

bead house A dwelling for poor religious people, located near the church in which the founder was interred, and for whose soul the beadsmen or beadswomen were required to pray.

beading Collectively the bead moldings used in ornamenting a given surface; also see bead.

beading plane, bead plane A plane having a curved cutting edge for shaping beads in wood.

bead-jointed Said of a carpentry joint having a bead along the edge of one piece to make the joint less conspicuous.

bead molding 1. A small, convex molding of semicircular or greater profile; also called a half round; a roundel; a baguette. 2. Same as paternoster.

bead plane See beading plane.

bead weld Same as surfacing weld.

beadwork Same as beading.

beakhead An ornament; any of several fantastic, animal-like heads with tapered, down-pointed beaks; frequently used in richly decorated Norman doorways. Also see catshead.

beakhead molding, bird’s-beak molding Same as beak molding, 2.

beaking joint A joint formed by several heading joints occurring in one continuous line; esp. used in connection with the laying of floor planks.

beak molding 1. A pendant fillet with a channel behind it on the edge of a corona, larmier, or stringcourse, etc., so called because in profile it resembles a bird’s beak. 2. A molding enriched with carved birds’ heads or beaks.

beam 1. A structural member whose prime function is to carry transverse loads, as a joist, girder, rafter, or purlin. The term beam may be modified by an adjective indicating its location; as, for example, an end beam or side beam. See anchor beam, binding beam, breastsummer beam, camber beam, ceiling beam, collar beam, cross beam, dragon beam, floor beam, ground beam, hammer beam, I-beam, laced beam, perimeter beam, summerbeam, tie beam, top beam, wind beam. 2. A group of nearly parallel rays of light.

beam anchor, joist anchor, wall anchor A metal tie used to anchor a beam or joist to a wall, or to tie a floor securely to a wall.

beam-and-column construction Same as post-and-lintel construction.

beam-and-girder construction A system of floor construction in which the load is distributed by slabs to spaced beams and girders.

beam-and-slab floor A floor system in which a concrete floor slab is supported by reinforced concrete beams.

beam bearing plate A foundation plate (usually of metal) placed beneath the end of a beam, at its point of support, to distribute the end load at the point.

beam blocking 1. Boxing-in or covering a joist, beam, or girder to give the appearance of a larger beam. 2. Strips of wood used to create a false beam.

beam bolster A rod which provides support for steel reinforcement in formwork for a reinforced concrete beam.

beam bottom The soffit of a beam.

beam box Same as wall box.

beam brick A face brick which is used to bond to a poured-in-place concrete lintel.

beam casing The enclosure of a steel beam in concrete or in an exfoliated vermiculite plaster; used to increase the fire resistance of the beam.

beam ceiling 1. A ceiling, usually of wood, made in imitation of exposed floor beams with the flooring showing between. 2. The underside of a floor, showing the actual beams, and finished to form a ceiling.

beam-column A beam which transmits an axial load as well as a transverse load.

beam compass An instrument used to draw large circles or arcs of circles for full-sized working drawings; has a long horizontal bar on which two movable heads slide to and fro, one of which carries a pencil, and the other a sharp-pointed pin or tracer, the distance between them determining the radius of the circle.

beam cutoff angle The angle, measured from the principal axis of the intensity of a light source, at which the light source cannot be seen.

beam divergence (Brit.) Same as beam spread.

beam encasement Same as beam casing.

beam fill, beam filling Masonry, brickwork, or cement fill, usually between joists or horizontal beams at their supports; provides increased fire resistance.

beam form A form which gives the necessary shape, support, and finish to a concrete beam.

beam hanger 1. A strap, wire, or other hardware device which supports framework from structural members. 2. A stirrup, 4.

beam infilling See infilling.

beam iron Same as beam anchor.

beam link The segment of a concrete beam between a brace and a column or between braces.

beam pocket 1. In a vertical structural member, an opening to receive a beam. 2. An opening in the form for a column or girder where the form for an intersecting beam is framed.

beam saddle Same as beam hanger.

beam side In a concrete form for a beam, the side panels of the form.

beam spread The angle between two directions (on opposite sides of the axis of a light beam, and in the same plane as the beam axis) in which the light intensity equals a stated percent of a maximum reference intensity.

beam-spread angle The width of a light beam, measured in degrees, at the meeting point between two imaginary lines at which the light intensity drops to half its maximum value.

beam test A test of the flexural strength (modulus of rupture) of concrete from measurements on a standard unreinforced concrete beam.

bearer 1. Any horizontal beam, joist, or member which supports a load. 2. A support for a landing or winder in a stair. 3. The ribbon board in balloon framing, which supports second-floor joists. 4. A horizontal member of a scaffold upon which the platform rests and which may be supported by ledgers.

bearer bracket Same as roofing bracket.

bearing 1. A bearer. 2. That portion of a beam, truss, or other structural member which rests on the supports. 3. The support for a shaft, axle, or trunnion. 4. In surveying, the horizontal angle between a line and a reference meridian adjacent to the quadrant in which the line lies.

bearing bar 1. A wrought-iron bar placed on masonry to provide a level support for floor joists. 2. A load-carrying bar which supports a grating and which extends in the direction of the grating span.

bearing bar centers The distance between centers of bearing bars in a metal grating.

bearing block A block which distributes a load on the surface beneath the block.

bearing capacity 1. The load per unit area that can be supported safely by the ground. 2. See pile bearing capacity. 3. The pressure that can be exerted on soil or soil rock without excessive yield. 4. Of a pile, the load required to produce a condition of failure.

bearing distance, span The length of a beam between its bearing supports.

bearing length The length of a structural beam between its supports.

bearing partition See load-bearing partition.

bearing pile A pile which carries a vertical load.

bearing plate A steel slab which is placed under a beam, column, girder, or truss to distribute the end reaction from the beam to its support.

bearing pressure The pressure on a bearing, 2; the load on a bearing surface divided by its area.

bearing stone A masonry unit in a wall that can support a load other than the units of which the wall is composed.

bearing stratum The rock or soil stratum (a) which carries the load transferred to it by a caisson, pile, or the like or (b) on which a concrete footing or mat bears.

bearing strength 1. The maximum load that a column, footing, joint, or wall can sustain at failure, divided by the effective bearing area. 2. The non-destructive limit of a pipe load; used to determine its supporting strength in the field.

bearing stress See bearing pressure.

bearing test A field or laboratory test to determine the bearing capacity of a soil sample, individual pile, pile foundation, or the like.

bearing wall A wall capable of supporting an imposed load. Also called a structural wall or loadbearing wall.

beaumontage A resin, beeswax, and shellac mixture used for filling small holes or cracks in wood or metal.

Beaux-Arts style A grandiose architectural style as taught at the Ecole des Beaux Arts in Paris primarily in the 19th century, widely applied until 1930 to large public buildings such as courthouses, libraries, museums, railroads, and to some pretentious residences. Characteristics often include formalism in design, symmetrical plans, heavily rusticated arched masonry, ashlar stone bases with rusticated stonework, especially on the ground floor and raised basement levels; sculptured figures; a massive and symmetric façade, often with a projecting central pavilion; a monumental attic story; commonly decorated with dentils; enriched entablatures; monumental flights of stairs; classical columns often set in close pairs; banded columns, engaged columns, coupled pilasters; highly decorated pilastered parapets; balconies; sculptured spandrels; decorative brackets; sculptured figures; ornamental details such as cartouches, floral patterns, Greek key designs, ornamental keystones, medallions; elaborately decorated panels, and the like; the roof, commonly a flat or low-pitched, hipped, or a mansard roof; often, domes and rotundas; rectangular windows symmetrically placed, with lintels overhead; arched dormers, balustraded windows, pedimented windows, or windows with balconets; doors, commonly paneled with a glass-paneled canopy over the primary entry-way, flanked by columns or pilasters; a wrought-iron grille on the exterior side of the entry door. Also called Beaux-Arts Classicism.

beaver board Same as composition board.

bed 1. In masonry and bricklaying, the side of a masonry unit on which it lies in the course of the wall—the underside when placed horizontally. 2. The layer of mortar on which a masonry unit is set. 3. The lower surface or side of a slate. 4. To set a glass pane in place with putty. 5. In layered stone used for building, a surface parallel to the stratification. 6. A layer (stratum) of rock between two bedding planes.

bed chamber An apartment or chamber intended for a bed, or for sleeping and resting.

bedding 1. Mortar, putty, or other substance used to secure a firm and even bearing, as putty laid in the rabbet of a window frame, or mortar used to lay bricks. 2. A base which is prepared in soil or concrete for laying masonry or concrete.

bedding coat The plaster coat which receives aggregate or other decorative material, impinged or embedded in its surface before it sets.

bedding course 1. The first layer of mortar at the bottom of masonry. 2. A cushion course.

bedding dot A small spot of plaster built out to the face of a finished wall or ceiling; serves as a screed for leveling and plumbing in the application of plaster.

bedding plane The surface at which two beds, layers, or strata join in stratified rocks.

bedding plants Annual and subtropical plants used for seasonal effects in landscaping.

bedding putty A putty, 1 that is placed in the rabbet of a window-opening in which the glass is bedded.

bedding stone A flat marble slab used by masons to check the flatness of rubbed bricks.

bed glazing See back putty.

bed joint 1. A horizontal layer of mortar on which masonry units are laid. 2. One of the radial joints in an arch. 3. A horizontal crack in a massive rock.

bed molding 1. A molding of the cornice of an entablature situated beneath the corona and immediately above the frieze. 2. The lowest member of a band of moldings. 3. Any molding under a projection, as between eaves and sidewalls.

bed place An alcove into which a bed is located; found, for example, in many houses in Europe and their derivatives.

bedplate A plate, frame, or platform which supports a heavy object such as a machine or furnace; a baseplate.

bed putty Same as back putty.

bedrock The hard, solid rock at the earth’s surface or underlying surface soil; can be utilized as a firm foundation for a building.

bedroom A room suitably furnished for sleeping.

bedroom community See satellite community; also called a dormitory suburb.

bed sill A horizontal timber at the base of a building of timber-framed construction; the timber rests on, or is set into, the ground; same as groundsill, 2.

bedstone A large flat stone that supports a structural member.

bed surface Of a brick, the in situ non-vertical surface intended to be joined by mortar.

bed-type filter In a water supply line, a filter containing a porous medium through which the water is forced as a result of the water pressure; used for the removal or reduction of suspended solid contaminants.

beech, beechwood A moderately high-density, fine-grained, durable, strong hardwood of North America and Europe. Whitish to light red-brown in color; used for small wood-turned parts and flooring.

beehive house Same as trullo.

beehive oven Same as bake oven.

beehive tomb, tholos tomb A monumental underground tomb in the form of a beehive, used in the Mycenaean period.

beetle A heavy mallet or rammer; used for driving stones into pavement, for driving wedges, etc.; a maul.

beggin, begging 1. A dwelling of larger size than a cottage. 2. In the north of England and in Scotland, a house. 3. A term especially applied to a hut covered with mud or turf.

beit hilani 1. In northern Syria, a type of palace in the first millenium B.C. having a forward section with two large transverse rooms, a portico with one to three columns, and a throne room. 2. In ancient Assyrian architecture, the pillared portico of a beit hilani, 1.

bel A unit of sound level which denotes the ratio between two quantities proportional to power; the number of bels equals the logarithm of this ratio, to the base 10; 1 bel = 10 decibels.

belection See bolection molding.

Belfast roof A bowstring roof.

Belfast sink A plumbing fixture consisting of a deep-sided basin, often made of stoneware, with a water supply and drain.

Belfast truss A bowstring truss, for large spans, which is constructed entirely of timber components; the upper member is bent, and the lower member is horizontal.

belfry 1. A bell tower, either attached to a church or standing alone. 2. A timber framework in a steeple that supports a bell.

Belgian block A type of paving stone generally cut in a truncated, pyramidal shape; laid with the base of the pyramid down.

Belgian truss See Fink truss.

belite A constituent of portland cement clinker; when pure, known as dicalcium silicate.

bell 1. The body of a Corinthian capital or a Composite capital, with the foliage removed; also called a vase or basket. 2. The portion of a pipe which is enlarged to receive the end of another pipe of the same diameter for the purpose of making a joint; also called a hub.

bell-and-spigot joint, bell-and-socket joint, spigot-and-socket joint A connection between two sections of pipe, the straight spigot end of one section is inserted in the flared-out end of the adjoining section; the joint is sealed by a caulking compound or with a compressible ring.

bell arch A round arch supported on large corbels, giving rise to a bell-shaped appearance.

bell cage The timber framework which supports the bells in a belfry or steeple.

bell canopy A gable roof to shelter a bell.

bell capital 1. A bell-shaped capital. 2. The bell-shaped core of a Corinthian capital to which the leaves and volutes appear to be attached.

bellcast eaves Same as flared eaves.

bellcast roof Same as a bell roof.

bell cote A small belfry astride the ridge of a church roof, often crowned with a small spire.

bell deck The belfry floor above the lower rooms in a tower.

belled caisson A caisson having an enlarged base.

belled excavation A part of a shaft or footing excavation, usually near the bottom and bell-shaped.

belled pier A pier having an enlarged end at the bottom of its shaft, often in the shape of a bell-like truncated cone.

bellexion molding See bolection molding.

bellflower A bell-shaped floral ornament; commonly, one of a string of such decorative elements.

bell gable A wall gable having one or more openings for bells.

bell house A tower-like building for housing bells, esp. in Ireland.

bellied Having a convex or bulging form.

belling In pier, caisson, or pile construction enlarging the base of a foundation element to increase its bearing area at the bearing stratum.

bell joint See bell-and-spigot joint.

bellows expansion joint In a run of piping, a joint formed with flexible metal bellows which compress or stretch to compensate for linear expansion or contraction of the run of piping.

bell pull A device once used to summon servants in an elegant home; in each room, the bell pull consisted of a small handle connected to a wire that was mechanically connected to a bell in the servants’ quarters. Thus, a pull on the handle rang a bell in the servants’ quarters; each bell pull produced a sound of different pitch, identifying the room calling for service.

bell roof A roof having a cross section similar to that of a bell, flaring out at its lower edge.

bell tower A tall structure supporting one or more bells; may be part of a building or an independent structure; also see belfry.

bell transformer A small transformer which supplies power, at low voltage, for operating a doorbell or the like.

bell trap A type of bell-shaped trap used in floor drains; its use is prohibited by the National Plumbing Code.

bell turret A small tower, usually topped with a spire or pinnacle, and containing one or more bells.

bell wire Small-diameter wire of low current-carrying capacity; covered with insulating material rated at 30 volts or less.

below grade Recessed below ground level.

belowstairs In the basement.

belt conveyor A power-driven endless belt that runs on idler wheels; used to carry building materials, etc.

belt course 1. A horizontal band of masonry extending horizontally across the façade of a building and occasionally encircling the entire perimeter; usually projects beyond the face of the building and may be molded or richly carved. Also called a stringcourse or band course; called a sill course if set at windowsill level. 2. A horizontal board across front face or around a building, often having a molding.

belt-driven machine Any machine powered by an external source connected to the machine by one or more belts.

belt loader A machine used in excavation; a layer of earth is removed with a cutting edge or rotating auger; then the excavated material is elevated by means of a conveyor belt so that it can be loaded into a hauling unit; a separate prime mover usually is required to move the machine forward.

belt sander A portable tool having a power-driven abrasive-coated continuous belt; used to smooth surfaces.

beltstone One of the stones in a belt course.

beluardetto In military architecture, a small bastion on a continuous parapet of a medieval fort; usually located in a large ditch in front of the main rampart.

belvedere 1. A rooftop pavilion from which a vista can be enjoyed. 2. A gazebo. 3. A mirador.

bema 1. A transverse space in a church a few steps above the floor of the nave and aisles, and separating them from the apse. 2. In a synagogue, a raised pulpit from which the Torah (Holy Bible) is read.

bematis Same as diaconicon, 1.

bench 1. A long seat, usually of wood, with or without a back, usually for several persons. 2. A berm, 6. 3. Same as pretensioning bed.

bench brake A bench-mounted machine used for bending sheet metal.

benched foundation Same as stepped foundation.

bench end A terminal wood facing on a church pew, often decorative.

bench hook, side hook Any device used on a carpenter’s bench to keep work from moving toward the rear of the bench.

benching 1. Concrete laid on the side slopes of drainage channels where the slopes are interrupted by manholes, etc. 2. Concrete laid on sloping sites as a safeguard against sliding. 3. Concrete laid along the sides of a pipeline to provide additional support.

bench mark In surveying, a marked reference point on a permanent, fixed object, such as a metal disk set in concrete, whose elevation (above or below an adopted datum) is known and from which the elevation of other points or objects may be determined.

bench plane A plane, 1 used primarily in benchwork on flat surfaces, as a block plane or jack plane.

bench sander A stationary power tool (usually mounted on a table or stand) which is equipped with a rotating abrasive disk or belt; used to smooth surfaces of material held against it.

bench stake Same as stake, 1.

bench stop A bench hook which is used to fasten work in place, often by means of a screw.

bench table A projecting course of masonry at the foot of an interior wall, or around a column; generally wide enough to form a seat.

bench terrace A level step cut into a hillside grade.

bench trimmer, trimming machine, guillotine A machine for cutting the ends of two pieces of wood to any desired angle.

bench vise An ordinary vise, 1 fixed to a bench, which is used to hold a material or component while it is being worked on.

benchwork Any work performed at a bench rather than on machines or in the field.

bend See pipe bend.

bender For pipes, see hickey, 2.

bending beam See tie beam.

bending iron A tool used to straighten or to expand flexible pipe, esp. lead pipe.

bending moment The moment which produces bending at a section of a beam or other structural member; equal to the sum of moments taken about the center of gravity of that section.

bending pin One of a number of pins in a curved line which are used in bending lead pipe.

bending schedule A chart showing the shapes and dimensions of every reinforcing bar and the number of bars required on a particular job; prepared by the designer or detailer of the reinforced concrete structure.

bending strength The ability of a structural member to resist breakage when subject to one or more external forces that cause it to bend.

bending stress The tensile or compressive stress resulting from the application of a nonaxial force on a structural member.

bending tool Same as hickey.

bend radius The smallest radius of curvature into which a material can be bent without damage.

beneficial occupancy The use of a project or portion thereof for the purpose intended.

beneficiation The improvement in the physical or chemical properties of a material by the removal or modification of undesirable components or impurities which it contains.

benefits (mandatory and customary) The personnel benefits required by law (such as social security, workmen’s compensation, and disability insurance), and by custom (such as sick leave, holidays, and vacation), and those which are optional with the individual firm (such as life insurance, hospitalization programs, pension plans, and similar benefits).

benitier A basin for holy water, usually set at the entrance to a church.

bent 1. Same as bent frame. 2. A rhizomatous grass, used where a resilient velvety texture is required.

bent approach An arrangement of two gateways not in line, so that it is necessary to make a sharp turn to pass through the second; for privacy in houses or temples, for security in fortifications.

bent bar A longitudinal reinforcing bar which is bent to pass from one face of a structural member to the other face.

bent chisel Same as corner chisel.

bent ferrule A ferrule having a 90° bend.

bent frame One of a number of sections in a timber framework that is transverse to the length of a large barn or house of timber-frame construction; each section, usually designed to carry both lateral and vertical loads, was commonly constructed on the ground and then raised to its upright position with the assistance of neighbors, as described under barn raising.

bent glass Flat glass that has been reshaped while very hot to form a curved surface.

bent grass See bent, 2.

bentonite A clay, formed from decomposed volcanic ash, with a high content of the mineral montmorillonite; has the capability of absorbing a considerable amount of water, and swells accordingly.

bent shoe A base shoe molding which is bent on a radius.

bentwood Wood formed to shape by bending, rather than by carving or machining.

Berlin blue See Prussian blue, 2.

berliner, palladiana A type of terrazzo topping using small and large pieces of marble paving, usually with a standard terrazzo matrix between pieces.

berm 1. A continuous bank of earth alongside a road; a shoulder. 2. A continuous bank of earth piled against a masonry wall. 3. A strip of ground, formed into a ledge to support beams or pipes. 4. The horizontal surface between a moat and the exterior slope of a fortified rampart. 5. In earth excavation work, that portion of the excavation, usually sloped, left at the perimeter and removed as the sheeting and bracing are installed. 6. A narrow terrace or shelf built into an embankment, or the like, which breaks the continuity of an otherwise long slope.

Bermuda stone A soft limestone formed primarily of broken shells and coral; usually cut into rectangular blocks and used in building construction.

besant See bezant.

bestiary In a medieval church, a group of carved or painted creatures, often highly imaginative and symbolic.

BET. On drawings, abbr. for “between.”

bethel A place of worship.

Bethell process A process for preserving wood by impregnating the cells with creosote under pressure.

béton A kind of concrete; a mixture of lime, sand, and gravel.

béton armé Same as reinforced concrete.

béton brut Concrete as it appears when the framework is removed, so that the concrete surface reflects the framework joints, wood grain, and fasteners around which it was poured; often deliberately retained for architectural effect. See Brutalism.

bettering house An archaic term for poor-house.

bev In the lumber industry, abbr. for “beveled.”

bevel 1. The angle which one surface of a body makes with another surface when they are not at right angles. 2. See door bevel. 3. See lock bevel. 4. A bevel square.

bevel angle In welding, the angle which is formed between the prepared edge of a member and a plane perpendicular to the surface of the member.

bevel board A board cut to any required bevel; used in framing a roof, stairway, or other angular wood construction.

bevel chisel A chisel for cutting wood, having its cutting edge at an angle to the sides.

bevel collar Same as angle collar.

bevel cut Any cut not at right angles.

beveled See bevel.

beveled closer See king closer.

beveled edge Of a door; a vertical door edge which has a slope of

in. (0.3 cm) in 2 in. (5 cm) from a plane perpendicular to the door face. (See illustration p. 108.)

beveled halving, bevel halving A half-lap joint in which the abutting surfaces are cut at an angle to the plane of the timbers.

beveled joist A floor joist having its upper edges beveled.

beveled pipe A pipe which has one end angled so that it mates with a complementary pipe end.

beveled-rabbeted window stool A window stool which is rabbeted with a beveled profile to match the slope of the sill of the window frame.

beveled siding See clapboard.

beveled washer A metal washer having a bevel on one side, permitting a bolt or rod to pass through it but providing full bearing against a nut.

bevel jack A device for holding wood moldings in cutting a miter.

bevel joint In carpentry, a joint in which two pieces meet at other than a right angle.

bevel protractor A graduated semicircular protractor having a pivoted arm; used for measuring or marking off angles.

bevel siding See clapboard.

bevel square A carpenter’s tool, similar to a square but having a blade that can be adjusted to any angle.

bezant, besant, byzant An ornament shaped like a coin or disk; sometimes used in a series in decorative molding designs.

bezel, basil The bevel or sloping edge of a cutting tool, as an ax or chisel.

BFP Abbr. for backflow preventer.

Bh Abbr. for Brinell hardness.

Bhn Abbr. for Brinell hardness number.

bhp Abbr. for brake horse power.

BIA Abbr. for the Brick Industry Association, Reston, VA 201191-1525; formerly the Brick Institute of America.

biaxial bending The bending of a member about two perpendicular axes simultaneously.

bib, bibb See bibcock.

bibcock, bib, bibb, bib tap A faucet or stopcock which has its nozzle bent downward.

bibliotheca A library; a place to keep books.

bib nozzle Same as bibcock.

bib tap Same as bibcock.

bib valve An ordinary bibcock which is closed by screwing down a handle, thereby closing a washer disk onto a seating in the valve.

bicoca A turret or watchtower.

bicycle-wheel roof A roof structural system whose main structural members radiate from the center to the perimeter of the building, resembling a bicycle wheel.

bid 1. An offer to perform the work described in a contract at a specified cost. 2. A complete and properly signed proposal to do the work, 1 or designated portion thereof for the sums stipulated therein, supported by data called for by the bidding requirements.

bid bond A form of bid security executed by the bidder as principal and by a surety. Also see bid security and surety.

bid date The date established by the owner or the architect for the receipt of bids. Also see bid time.

bidder One who submits a bid for a prime contract with the owner, as distinct from a subbidder who submits a bid to a prime bidder. A bidder is not a contractor on a specific project until a contract exists between him and the owner.

bidding documents The advertisement or invitation to bid, instructions to bidders, the bid form, and the proposed contract documents including any addenda issued prior to receipt of bids.

bidding or negotiation phase The fourth phase of the architect’s basic services, during which competitive bids or negotiated proposals are sought as the basis for awarding a contract.

bidding period The calendar period beginning at the time of issuance of bidding requirements and contract documents and ending at the prescribed bid time. Also see bid time.

bidding requirements Those documents providing information and establishing procedures and conditions for the submission of bids. They consist of the notice to bidders or advertisement for bids, instructions to bidders, invitation to bid, and sample forms. Also see bidding documents.

bidet A low, basin-like plumbing fixture on which the user sits; used to wash the posterior parts of the body.

bid form A form furnished to a bidder to be filled out, signed, and submitted as his bid.

bid guarantee Same as bid security.

bid letting See bid opening.

bid opening The opening and tabulation of bids submitted by the prescribed bid time and in conformity with the prescribed procedures. Also see bid time.

bid price The sum stated in the bid for which the bidder offers to perform the work, 1.

bid security The deposit of cash, certified check, cashier’s check, bank draft, money order, or bid bond submitted with a bid and serving to guarantee to the owner that the bidder, if awarded the contract, will execute such contract in accordance with the bidding requirements and the contract documents.

bid time The date and hour established by the owner or the architect for the receipt of bids. Also see bid date.

biennial plant A plant whose life cycle is completed in two growing seasons.

bifolding door A door having two pairs of leaves, each pair consisting of an outer and an inner leaf which are hinged together; each inner leaf (the one nearest the center line) is hung from an overhead track; each outer leaf is pivoted at the jamb.

bifora Divided by a colonnete into two arches.

biforate Having two doors or windows.

bifrons Having two fronts or faces looking in opposite directions, as a double herm.

bifronted Same as bifrons.

biga A chariot similar to a quadriga but drawn by two horses.

BIL See basic insulation level.

bilection molding See bolection molding.

billet 1. A common Norman or Romanesque molding formed by a series of circular (but occasionally square) cylinders, disposed alternately with the notches in single or multiple rows. 2. A steel slab which is placed under a column to distribute the load, as from the column to the supporting masonry. 3. A timber which is sawn on three sides and left rounded on the fourth. 4. A wood block from which smaller pieces of structural lumber can be cut.

bill of materials Same as quantity survey.

bill of quantities Same as quantity survey.

bimah A bema, 2.

bimetallic corrosion A type of corrosion which takes place between two dissimilar metals that make prolonged contact with each other.

bimetallic element A device formed of two metals which are bonded together, each having a different coefficient of thermal expansion; used in temperature-indicating and temperature-controlling devices.

bin A container for storing loose materials, such as sand or crushed rock.

binder 1. A cementing material, either hydrated cement or a product of cement or lime and reactive siliceous material, for holding loose material together. 2. A component of an adhesive composition that is primarily responsible for the adhesive forces which hold two bodies together. 3. A binding agent. 4. A soil binder. 5. A binding joist. 6. A binding stone. 7. Any member which binds together components of a framing structure.

binder course, binding course 1. In asphaltic concrete paving, an intermediate course between the course base and the surfacing material; consists of intermediate-size aggregate bound by bituminous material. 2. A row of masonry units laid between, and used to bind, an inner and an outer wall.

binder lead The lead strips used to form the perimeter around a small pane of glass.

binder soil Material consisting primarily of fine soil particles (fine sand, silt, clay, and colloids); has good binding properties. Also called clay binder.

binding agent That liquid portion of a paint which solidifies and binds together the pigment particles and develops adhesion to the painted surface.

binding beam Any timber which serves to tie together various parts of a frame. For example, see summerbeam.

binding course See binder course.

binding joist, binder A beam which supports the common joists of a wood floor above and the ceiling joists below; commonly, joins two vertical posts.

binding piece A piece of lumber which is nailed between two opposite beams or joists to prevent lateral deflection; a straining beam.

binding post A post attached to an electric cable, wire, or apparatus, for making a connection to it conveniently.

binding rafter A longitudinal timber which supports the roof rafters between the ridge and the eaves, as a purlin.

binding screw A type of setscrew.

binding stone A stone which bonds masonry together, as a perpend; a binder, 6.

binding wire Same as tie wire.

binnacle An obsolete term for a dwelling place.

biparting door A double door having two leaves (one on each side of the center line of the door) which slide in the same plane and meet at the center line.

birch A moderately strong, high-density wood of North America and northern Europe, yellowish white to brown in color; its uniform texture and figure are well suited for veneer, flooring, and turned wood products.

birdbath A small puddle of water occurring at a low spot in paving.

birdcage scaffold A temporary platform, which supports workers and materials, and has more than two rows of upright posts and cross-pieces.

bird peck A small spot or hole in wood usually caused by a woodpecker. Subsequent tree growth develops distorted grain around the injury.

bird’s-beak molding See beak molding, 2.

bird screen A frame fitted with a wire mesh; used to prevent birds from entering an opening, such as at a chimney hood or a ventilation opening.

bird’s eye An eye-shaped figure in wood formed by small sharp depressions in the growth rings. Found particularly in sugar maple but also in other wood species.

bird’s-eye lamp See incandescent direct-light lamp.

bird’s-eye maple Wood of the sugar maple tree, cut so as to produce a wavy grain with numerous small, decorative, circular markings.

bird’s-mouth 1. A notch cut across the grain at one end of a timber for its reception on the edge of another piece, such as a wall plate. 2. The angle between two components, usually between 90 and 180 degrees.

bird’s-mouth joint A wood joint formed by a cut into the end of a timber to fit over a cross timber; for example, cut into a rafter.

bisellium In ancient Rome, a seat of honor, or a state chair, reserved for persons of note or persons who had done special service for the state.

bisomus A sarcophagus with two compartments.

bisque A tile that has been fired once but not glazed.

bit 1. A small tool which fits in the chuck of a brace or drill, and by which it is rotated—thereby cutting or boring a hole. 2. The projecting blade of a key which is cut in a manner to actuate the tumblers and permit the lock bolts to be operated. 3. That part of a soldering iron which transfers heat and solder to the joint. 4. The cutting edge of a plane.

bitbrace A brace, 3.

bite In glazing, the distance by which the inner edge of a frame (or a stop) overlaps the edge of the glass or panel.

bit gauge, bit stop A metal piece temporarily fixed to a bit to prevent drilling too deeply in a blind hole.

bit key A key having a projecting blade or wing which engages with and actuates the bolt and tumblers of a lock.

bit stock A brace, 3.

bit stop See bit gauge.

bitumen A semisolid mixture of complex hydrocarbons derived from coal or petroleum, as coal-tar pitch or asphalt; before application, usually dissolved in a solvent, emulsified, or heated to a liquid state.

bitumen macadam A macadam in which the aggregate, of relatively uniform size, has been coated with bitumen.

bituminized fiber pipe A lightweight drainage pipe fabricated of cellulose fiber combined with coal tar.

bituminous cement A black substance available in solid, semisolid, or liquid states at normal temperatures; composed of mixed indeterminate hydrocarbons; appreciably soluble only in carbon disulfide or other volatile liquid hydrocarbon; esp. used in sealing built-up roofing and between joints and in cracks of concrete pavements.

bituminous coating An asphalt or tar compound used to provide a protective finish for a surface.

bituminous concrete See asphaltic concrete.

bituminous distributor A truck equipped with a tank body and with a system for pumping hot tar, road oil, or other bituminous material through a perforated spray bar at the rear; used to lay down a surface coating of the bituminous material.

bituminous emulsion A suspension of minute globules of bituminous material in water (or of minute globules of water in a liquid bituminous material); used as a protective coating against weather, esp. where appearance is not important.

bituminous felt See asphalt prepared roofing.

bituminous grout A mixture of bituminous material and aggregate such as sand; liquefies when heated; suitable for pouring in joints or cracks as a sealant; cures in air.

bituminous hot-mix Any pavement, having asphalt as the binder, which is laid while hot.

bituminous paint A low-cost paint containing asphalt or coal tar, a thinner, and drying oils; used to waterproof concrete and to protect piping where bleeding of the asphalt is not a problem.

bituminous varnish A dark-colored varnish (either of the oil or spirit type) that contains bituminous ingredients.

bituminous waterproofing A waterproofing material such as tar.

bivalate, bivallate In military architecture, a pair of defensive ditches and earth embankments, usually concentric, that surround a mound or medieval fort.

BK SH On drawings, abbr. for “book shelves.”

BL On drawings, abbr. for building line.

B/L Abbr. for “bill of lading.”

B-labeled door A door carrying a certification from the Underwriters’ Laboratories, Inc. that it meets the requirements for a class-B door.

black ash mortar, black mortar A mixture of high-calcium lime, water, and ashes or clinker which relies on its pozzolanic properties for its hard set.

blackbody 1. A body whose radiation at each wavelength is the maximum possible for any electromagnetic radiator at that temperature. 2. A body that absorbs all light which is incident on it and consequently looks black.

black bolt A hot-formed bolt covered with black scale, not of uniform diameter; used in steel construction.

black diapering Same as diaperwork.

black ebony See ebony.

black japan A high-quality bituminous paint used as a metal varnish.

black light Invisible ultraviolet electromagnetic energy near the visible spectrum; useful for exciting fluorescent paints, dyes, etc., so that they become visible.

black light fluorescent lamp A fluorescent lamp whose phosphor is designed to emit black light.

black locust See locust.

black mortar See black ash mortar.

black steel pipe Uncoated steel pipe, called “black” because of the dark-colored iron-oxide scale formed on its surface; usually used for low-pressure hot-water heating pipes.

blackout switch On a theater stage, a master switch that extinguishes all stage lights simultaneously.

black plate Uncoated cold-rolled steel in sheets, usually 12 in. (30.5 cm) to 32 in. (81.3 cm) in width.

blacksmith shop A shop where iron bars are forged into objects such as tools, and where horses are fitted with horseshoes.

blacktop See asphaltic concrete.

blade 1. The flat metal surface of a trowel with which plaster is applied. 2. The cutting part of a knife, plane, etc. 3. The broad, slightly concave surface of a bulldozer, or the like, which pushes the material being moved. 4. One of the principal rafters of a roof. 5. To remove, spread, or level a material such as dirt, or gravel by the use of a grader.

blade frequency The number of times fan blades pass a given point per second; equals the number of blades in the fan multiplied by the fan speed in revolutions per second.

blader grader Same as grader.

Blaine apparatus An apparatus for measuring the surface area of a finely ground cement, or the like, on the basis of its air permeability.

Blaine fineness The fineness of a powdered material, such as cement, as determined by the Blaine apparatus; usually expressed as a surface area in square centimeters per gram.

Blaine test A test for determining the fineness of cement, or other fine material, on the basis of the permeability to air of a sample of the material prepared under specified conditions.

blanc fixe A fine-grained barium sulfate, used as white pigment in paints.

blandel Same as apostilb.

blank arcade Same as blind arcade.

blank door 1. A recess in a wall, having the appearance of a door; usually used for symmetry of design. 2. A door which has been sealed off but is still visible.

blanket encumbrance A lien or mortgage which is applied proportionately to every lot within a subdivision.

blanket grouting See area grouting.

blanket insulation Thermal insulation, commonly fabricated of fibrous glass material, with or without confining envelope, facings, or coatings; in properly selected density and thickness, can conform to curved or irregular surfaces of equipment, large-diameter piping, or tanks; also used as an acoustical material behind a facing material or as a component in sound-insulating construction.

blank flange A flange without bolt holes; otherwise complete.

blank jamb A vertical member of a door-frame which has not been prepared to receive hardware.

blank wall, blind wall, dead wall A wall whose whole surface is unbroken by a window, door, or other opening.

blank window, blind window, false window 1. A recess in an external wall, having the external appearance of a window. 2. A window, which has been sealed off but is still visible.

blast area The area in which the loading of explosives and the blasting operations take place.

blast cleaning Any cleaning process, such as sandblasting, in which an abrasive is directed at the surface with high velocity.

blast freezer An upright freezer in which air, at a very low temperature, is circulated by blowers; used to freeze foods in minimum time.

blast-furnace slag The nonmetallic product, consisting essentially of silicates and aluminosilicates of calcium and other bases, which is developed in a molten condition simultaneously with iron in a blast furnace. The solidified product is further classified by the process by which it was brought from the molten state; also see air-cooled blast-furnace slag, expanded blast-furnace slag, granulated blastfurnace slag.

blast-furnace slag cement See portland blast-furnace slag cement.

blast heater A heater consisting of a set of heat-transfer coils (or sections) through which air is drawn or forced by a fan at relatively high velocities.

blast hole A hole drilled into rock in which an explosive charge is to be placed.

blasthole drill A drill which cuts holes in rock for the placement of explosives.

blasting Using explosives to loosen rock or other closely packed materials.

blasting agent According to OSHA: a material or mixture consisting of a fuel and oxidizer used for blasting, but not classified as an explosive and in which none of the ingredients is classified as an explosive, provided the furnished product cannot be detonated with a No. 8 test blasting cap when confined.

blasting cap A metallic tube closed at one end, containing a charge of one or more detonating compounds, and designed for and capable of detonation from the sparks or flame from a safety fuse inserted and crimped into the open end.

blasting mat A heavy, flexible covering (usually made of woven-wire rope or cordage); covers an area during blasting, to prevent rock or earth fragments from flying about.

blast-resistant door A steel door which has been fabricated to resist dynamic stresses caused by blast pressures up to 3,000 lb per sq in. (211 kg per sq cm).

bldg Abbr. for building.

bleachers A grandstand (or section within a grandstand) where the seats are usually not provided with backrests.

bleacher seating A stand of tiered planks providing undivided space for seating.

bleaching A chemical or photochemical reaction which whitens or removes color from a surface.

bleb A blister or small bubble in a fluid or in a material (such as glass) that has solidified.

bled timber Wood from trees tapped for resin. Although appearance may be affected, strength is usually not.

bleeder A small valve used to drain fluid from a pipe, radiator, vessel, etc.

bleeder pipe, bleeder tile A pipe, usually of structural clay, for carrying water from a drainage tile to a drain or sewer.

bleeding 1. The upward penetration of a coloring pigment from a substrate through a topcoat of paint. 2. The oozing of grout from below a road-surfacing material to the surface in hot weather. 3. Exudation of one or more components of a sealant, with possible absorption by adjacent porous surfaces. 4. The autogenous flow of mixing water within, or its emergence from, newly placed concrete or mortar; caused by the settlement of the solid materials within the mass or by drainage of mixing water; also called water gain. 5. The diffusion of coloring matter through a coating from the substrate, or the discoloration that arises from such a process.

bleeding capacity The ratio of the volume of water which is released by bleeding, 4 to the volume of mortar or paste.

bleeding rate The rate at which water is released by bleeding, 4 from mortar or paste.

bleeding test A test (ASTM C232) for measuring the tendency for water to rise to the surface of freshly placed concrete.

bleed-through, strike-through Discoloration in the face plies of wood veneer constructions caused by oozing of glue through the face veneers.

blemish In wood, marble, etc., usually a minor appearance defect that does not necessarily affect durability or strength.

blended cement A mixture of portland cement and other material such as granulated blast-furnace slag, pozzolan, hydrated lime, etc., combined either during or after the finish grinding of the cement at the mill.

blended lamp Same as self-ballasted lamp.

blender A soft round-tipped paintbrush used for blending colors and smoothing out brush marks left by coarser brushes.

blending In hot-water systems, the mixing of hot water with cold water in order to raise the cold-water temperature. Blending usually takes place at the point of use.

blending valve A three-way valve which permits liquid entering the valve to be mixed with liquid that recirculates through the valve; used to obtain a desired liquid temperature.

blight In plants, a fungus disease causing them to wither.

blighted area Any area which has become an economic and aesthetic liability to a community.

blind 1. A device to obstruct vision or keep out light; usually a shade, a screen, or an assemblage of light panels or slats. 2. A solid disk inserted in a pipe joint or union to prevent the flow of water during the repair of a water distribution system.

blind alley A road, alley, or passageway open at one end only. Also see cul-de-sac.

blind arcade A decorative row of arches applied to a wall as a decorative element, esp. in Romanesque buildings.

blind arch An arch in which the opening is permanently closed by wall construction.

blind area An area built around the outside of a basement wall to prohibit penetration of moisture.

blind attic An attic space, floored but unfinished inside. Also see loft, 1.

blind casing, subcasing A rough window frame or subcasing to which trim is added.

blind door 1. Same as blank door. 2. A louvered door.

blind dovetail Same as secret dovetail.

blind drain A drain which is not connected to a sewage system.

blind fast A catch for securing a blind or a shutter, in either an open or a closed position.

blind flange A flange which closes the end of a pipe.

blind floor Same as subfloor.

blind header In an interior of a brick wall, a header concealed so that it does not appear on the face of the wall.

blind hoistway A hoistway that does not have a hoistway door at every floor.

blind hole A hole which is drilled only partway through the thickness of the material.

blinding 1. A thin layer of lean concrete or of fine gravel or sand applied to a surface to fill voids and to provide a smoother, cleaner, drier, or more durable finish; esp. fine gravel or sand over freshly placed asphaltic concrete. 2. Sprinkling small stone chips over a freshly tarred road. 3. Placing a material over piping to completely cover it. 4. Compacting of soil directly over a drain tile, thereby reducing its tendency to move into the tile.