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 the 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 arriere-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 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.
backbend = 1. Same as backband. 2. At the outer edge of a metal door or window frame, the face which returns to the wall suface.
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-reppelent 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 the 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 recces 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 subtances 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 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.