Search Results for B back vent In plumbing, a venting device installed in the downstream side of a trap to protect it from siphonage. backfill Earth, soil, or other material used to replace previously excavated material, as around a newly constructed wall. backflow preventer A device or means to prevent backflow into the potable water system. backhoe A powered excavating machine used to cut trenches by drawing a boom-mounted bucket through the ground toward the machine. The bucket is raised and swung to either side to deposit the excavated material. backup That part of a masonry wall behind the exterior facing. balcony A platform that protrudes from a building. It can be cantilevered or supported from below, and is usually protected by a railing or balustrade. baluster (banister) One of a series of short, vertical supporting elements for a handrail or a coping. bank-run gravel (bank gravel, run-of-bank gravel, all-in-aggregate) Granular material excavated without screening, scalping, or crushing. This type of gravel is a naturally occurring aggregate comprised of cobbles, gravel, sand, and fines. bar joist A light steel joist of open-web construction with a single zigzag bar welded to upper and lower chords at the points of contact. Used as floor and roof supports. bar support (bar chair) A rigid device of formed wire, plastic, or concrete, used to support or hold reinforcing bars in proper position during concrete operations. base (scrubboard, skirting board, washboard) A board or molding used against the bottom of walls to cover their joint with the floor and to protect them from kicks and scuffs. base course A layer of material of specified thickness constructed on the subgrade or subbase of a pavement to serve one or more functions, such as distributing loads, providing drainage, or minimizing frost action. batt insulation Thermal or sound-insulating material, such as fiberglass or expanded shale, which has been fashioned into a flexible, blanket-like form, often with a vapor barrier on one side. Batt insulation is manufactured in dimensions that facilitate its installation between the studs or joists of frame construction. batten (1) A narrow strip of wood used as siding to cover the joints of parallel boards or plywood. The resultant pattern is referred to as board and batten. (2) A furring strip fastened to a wall to provide a base from lathing or plastering. (3) In roofing, a strip of wood placed over boards or roof structural members to provide a base for the application of wood or slate shingles, or clay tiles. batten seam In metal roofing, a seam fabricated around a wood strip. batter To incline from the vertical. bay In construction, the space between two main trusses or beams. bay window A usually large window or group of windows that projects from a wall of a building forming a recess within the building. beam A horizontal structural member, such as a girder, rafter, or purlin, which transversely supports a load and transfers the load to vertical members, such as columns and walls. beam bearing plate A metal plate positioned under the end of a beam to distribute the reaction load over a larger area. When used under a column, it is called a loose plate. beam pocket A space left open in a vertical structural member to receive a beam. bearing wall Any wall that supports a vertical load as well as its own weight. bed The mortar into which masonry units are set. berm An artificially placed continuous ridge or bank of earth, usually along a roadside. Also called a shoulder. Bit., Bitum. Bituminous bituminous base course (black base) Bituminous bound aggregate serving as a foundation for binder courses and surface courses in asphalt paving operations. bituminous costing Any waterproof or protective coating whose base is a compound of asphalt or tar. black steel pipe Steel pipe that has not been galvanized. bleeder A small valve used to drain fluid from a pipe, radiator, or small tank. blind nailing (concealed nailing, secret nailing) Nailing performed so that the nailhead cannot be seen on the face of the work. blister Usually an undesirable moisture and/or air-induced bubble or bulge, which often indicates that some kind of delamination has taken place. Blisters can occur between finish plaster and the base coat, between paint or varnish and the surface to which it has been applied, between roofing membranes or between membrane and substrate, between reinforcing tape and the gypsum board to which it has been adhered, etc. block A usually hollow concrete masonry unit or other building unit, such as glass block. blocking Small pieces of wood used to secure, join, or reinforce members, or to fill spaces between members. blow count (1) The number of times that an object must be struck to be driven into the soil to a desired or specified depth. (2) In soil borings, the number of times a sample spoon must be struck to be driven 6" or 12". BM. Beam board and batten A type of siding in which the joints between vertically placed boards or plywood are covered by narrow strips of wood. board foot The basic unit of measurement for lumber. One board foot is equal to a 1" thick board, 12" in width and 1' in length. board insulation (insulating board, insulation board) Lightweight thermal insulation, such as polystyrene, manufactured in rigid or semi-rigid form, whose thickness is very small relative to its other dimensions. boiler plate Standard text used in documents such as contract agreements. bollard A series of short posts set to prevent vehicular access or to protect property from damage by vehicular encroachment. A bollard is sometimes used to direct traffic. bolster In concrete, an individual or continuous support used to hold reinforcing bars in position. Usually used in slab work. bond The adhesion and grip of concrete or mortar to reinforcement or to other surfaces against which it is placed, including friction due to shrinkage and longitudinal shear in the concrete engaged by the bar deformations. bond beam A horizontally reinforced concrete or concrete masonry beam built to strengthen and tie a masonry wall together. A bond beam is often placed at the top of a masonry wall with continuous reinforcing around the entire perimeter. bond breaker A material used to prevent adhesion between freshly placed concrete and the substrate. bonded roof A type of roofing guarantee offered by the manufacturer which may or may not be purchased by the owner and which covers materials and/or workmanship for a stated length of time. bow The longitudinal deflection of a piece of lumber, pipe, rod, or the like, usually measured at its center. bow window A window that projects from the wall in the shape of an arc. box column A built-up, hollow column, usually square in shape, used in porch construction. box out To make a form that will create a void in a concrete wall or slab when the concrete is placed. branch circuit A portion of the electric system which extends wiring beyond the fuse or other device that is protecting that circuit. branch duct In HVAC, a smaller duct that branches from the main duct. At each branch duct, the cross-sectional area of the main duct is reduced. branch sewer A sewer that receives sewage from a relatively small area and is connected to a main sewer or manhole. braze To join two pieces of metal by soldering them together with a nonferrous metal such as brass. brick A solid masonry unit of clay or shale, formed into a rectangular prism while plastic, and then burned or fired in a kiln. brick anchor Corrugated fasteners designed to secure a brick veneer to a structural concrete wall. brick veneer A facing of brick laid against a structural wall but not bonded to the wall, and which bears no load other than its own weight. bridging A method of lateral bracing between joists for stiffness, stability, and load distribution. British thermal unit (BTU) A standard measurement of the heat energy required to raise the temperature of one pound of water one degree Fahrenheit. broom finish concrete Concrete that has been brushed with a broom when fresh in order to improve its traction or to create a distinctive texture. brown coat (floating coat) In two-coat wet-wall construction, the first rough coat of plaster applied as a base coat over lath or masonry. buck The wood or metal subframe of a door, installed in a wall to accommodate the finished frame. building codes The minimum legal requirements established or adopted by a government such as a municipality. Building codes are established by ordinance, and govern the design and construction of buildings. building inspector An official employed by a municipal building department to review plans and inspect construction to determine if they conform to the requirements of applicable codes and ordinances, and to inspect occupied buildings for violations of the same codes and ordinances. building main The water supply pipe (including fittings) that extends from the water main or other source of supply to the first distribution branch of a building. building paper A heavy, asphalt-impregnated paper used as a lining and/or vapor barrier between sheathing and an outside wall covering, or as a lining between rough and finish flooring. building permit A written authorization required by ordinance before construction on a specific project can begin. A building permit allows construction to proceed in accordance with construction documents approved by the building official. building services The utilities, including electricity, gas, steam, telephone, and water, supplied to and used within a building. building storm drain A drain in a building that conveys rainwater, surface water, condensate, and similar discharge to a building storm sewer that, in turn, extends to a specified point outside the building. building trap (main trap) A fitting installed on the outlet side of a building to prevent odors and gases from passing from a sewer to the plumbing system of the building. built-up beam (1) A metal beam made of beam shapes, plates, and/or angles that are welded or bolted together. (2) A concrete beam made of precast units connected through shear connectors. (3) A timber beam made of smaller pieces that are fastened together. built-up roofing (composition roofing, felt-and-gravel roofing, gravel roofing) A continuous roof covering made up of various plies or sheets of saturated or coated felts cemented together with asphalt. The felt sheets are topped with a cap sheet or a flood coat of asphalt or pitch, which may have a surfacing of applied gravel or slag. bulkhead A partition in concrete forms to separate placings. burnish To polish to a smooth, glossy finish. bus (bus bar) An electric conductor, often a metal bar, that serves as a common connection for two or more circuits. A bus usually carries a large current. butt hinge The common form of hinge consisting of two plates, each with one meshing knuckle edge, connected by means of a removable or fixed pin through the knuckles. buttress An exterior pier of masonry construction, often sloped, which is used to strengthen or support a wall or absorb lateral thrusts from roof vaults. 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