Your Handbook for understanding Architecture:


Ba - Ba
Bb - Bl
Bm - Br
Bs - Bz

Back 1) A location opposite to face, usually hidden

2) To move in an opposite direction or to return to a start position
Back boiler A small boiler fitted at the back of the hearth of an open fireplace or in a room heater to provide hot water and sometimes to heat radiators
Back Lintel The lintel supporting the backing of a wall and seen on the face
Back Painting Painting the unseen face of building board to give balanced construction and prevent buckling or cracking from an impervious paint system applied to the face alone
Back Propping The replacement of props under a slab after stripping of formwork, to provide support while it gains strength and to reduce creep
Back Putty The putty behind a pane of glass or other glazing as bedding between it and the rebate
Back Saw A hand saw stiffened with a heavy fold of steel or brass along its back, such as tenon saw
Back Sawing The breaking down of timber by flat sawing
Back Shutter Formwork to the top face of a steeply sloping concrete slab, to hold the fresh concrete during placing and vibration
Back Siphonage The sucking back of dirty water from within a building leading to backflow into a water main if its pressure drops.
Back Siphonage preventer A valve in a water main with two non return mechanism separated by a self draining chamber
Backactor A backhoe
Backdraught / Backdraft The inrush of air (e.g. when a door is opened) into a closed, airtight room containing an oxygen starved, smoldering fire, as the hot gases inside are cooled and contract, drawing smoke back towards the fire.
Backer A backup strip
Backer board Gypsum baseboard
Backfall A slope in a gutter (or any gravity drain) that is opposite to the intended direction of flow, resulting in pounding or backflow
Backfilling Material returned into an excavation, around foundations or over buried services and their surround. It is placed in layers or lifts that are individually compacted
Back-flap hinge A hinge with wide flaps, screw fixed to the face of a door and frame, on a door too thin to be carried on butt hinge
Backflow Movement of a fluid in the opposite direction to the natural or intended direction of flow.
Backflow Valve A back-siphonage preventer
Background Drawing A simplified floor plan of a building, used to help in coordinating the preparation of shop drawings for building services (such as air conditioning)
Background Heating A heating system run at a low temperature, supplemented by gas or electric fires etc. during periods of occupancy and cold weather.
Background, Backing A surface on which plasterwork is applied
Backgutter A roof gutter on a uphill side of a chimney
Backhoe, Backacter A versatile excavator with a bucket on a end of an arm, rather like a giant human arm
Backing Support material behind a facing, such as concrete behind a stone
Backing Coat Any coat of plaster other than finishing coat
Backings Firring strips on joints, or any backing
Backnut A nut used to make a tight and locked joint
Backset, Set back The distance from the spindle of a door lock to the edge of door leaf
Backshore, jack An outer support in raking shores, under the rider shore
Backup Strip, Backer A strip of compressible foam plastic inserted into a movement joint to limit the depth of sealant to half the joint width.
Backward curved blade An efficient aerofoil shaped blade of centrifugal fan, which does not overload the motor if the discharge is blocked
Backward Pass A calculation for a programme using the critical path method working from the end event to the beginning event, to find the latest dates for each activity that will still give the earliest completion date calculated from the forward pass
Baffle A device for breaking up the flow of air, water or light, often used as a diffuser
Bag Filter An air filter used in air conditioning in which the air passes through bags
Bag Plug An inflatable drain plug used for a drain test
Bagasse Board Cane Fibre Board
Bagged joints A flush joint made by rubbing brickwork with sacking
Bagging, Bag Rendering Rubbing cement mortar over the face brickwork using sacking, to fill in small holes and to leave a rough textured surface suitable for painting
Bailey Bridge A bridge prefabricated for rapid erection.
Bakelite A type of plastic
Balanced construction A method of construction of wood based building boards with equal thickness of wood in both directions of the grain.
Balanced Flue A double Flue made so that the draught is balanced by running its two halves (usually concentric) to a shared terminal.
Balanced Sash A sash window with counterweights or springs
Balancing The adjustment of flow of water or air through radiation or air terminal nits (air balancing) so that each receives enough.
Balancing Valve A lockshield valve for balancing the flow to radiators.

1) A horizontal cantilevered projection including a handrail or balustrade to serve as passage or sitting out place.

2) Platform extension to a wall.

Baldacchino Canopy over a throne or altar.
Ball catch, bullet A cupboard door fastener with a spring loaded ball projecting slightly from a mortice in the door. The ball engages with a hole in a striking plate and holds by friction
Ball Cock A ballvalve
Ball test A drain test using a ball that fits into a pipe with about 12mm clearance. The ball is flushed down the pipe to a manhole to detect any partial blockage

1) Unscreened gravel containing sand, grit and stones of less than boulder size, sometimes used to make concrete

2) Material used for loading sometimes against uplift from the wind or water pressure.

3) An electrical choke in the control gear of a fluorescent tube

Ballast Grating, Gravel Guard A screen in front of a rainmaker outlet to stop gravel ballast entering
Balloon framing House with timber frame construction, with studs two stories high from the bottom plate to the roof plate, past the floor joists which are nailed to them
Balloon Grating A large strainer over a rainwater outlet
Ballottini Small Glass beads used in reflective paint.
Ballvalve, Floatvalve A float operative valve used to control the flow of water into a cistern. It may have a delayed but rapid shut off to stop dribbling. Ballvalves often prevent waterhammer by releasing over pressure

1) Pillar or column supporting a handrail or coping.

2) A post in a balustrade of a bridge or a flight of stairs


1) A protective guard rail to prevent people falling, at the edge of a stair, landing or a platform, with closely spaced infill such as balusters from the handrail down to the floor

2) A row of balusters joined by a rail.

Band Course A string Course
Band Saw A power saw with a continuous steel belt driven around two three pulleys. Used mostly for cutting timber, band saws range in size from large sawmill units with tungsten tipped teethes for the initial breakdown of logs to small benchtop units for fine joinery work
Banding A lipping
Banister A baluster
Bank Cube Undisturbed volume of ground, before it is excavated
Bank of lifts Several lifts at a common location, usually with shared controls

1) A long narrow shape, such as metal or wooden glazing bar or a steel reinforcement bar

2) A practical unit for pressure widely used in Europe, close to one atmosphere. It is an exact SI Unit (1 bar = 100kN/Sq.Mt. = 100kPa dd= about 10mt head of water

Bar Bender A bending tool or a power bender
Bar Bending Schedule A list of reinforcement bars giving their location and details of cutting and bending
Bar Chair A support for a top layer of reinforcement bars in a concrete slab in the shape of a chair, either bent on site from small diameter bar or factory produced from wire
Bar Chart A programme showing the work dates of each trade represented by bars. It is easy to understand, unlike master arrow diagram
Bar schedule A bar bending schedule
Bar setting Steel fixing
Bar Spacer A small plastics accessory used to hold reinforcement away from formwork, at the correct cover distance
Barge Board, verge

1) Slopping roof trim of wood, plastics or metals fixed in pairs along the edge of a gable to cover the roof timbers and protect them from rain.

2) A brick coping to a gable wall, or the tiles next to the gable, slightly overhanging

Barge Flashing A flashing over a barge board
Barium Plaster, X-ray Plaster A radiation protection plaster containing barytes aggregates and gypsum plaster or portland cement as a binder, used on the walls of X-ray room to reduce the amount of radiation penetrating them
Barn A building in which grain, hay are kept.

1) In architecture, a mainly 17th century late Renaissance style of flowing forms, exuberant decoration and complex spatial compositions.

2) Originally a jewelers term applied to a rough pearl, now applied to a vigorous, exuberant style - grotesque, extravagant, whimsical - in vogue from the mid 16th to the late 18th century: sometimes used as equivalent to rococo.

Barrack A building for soldiers, especially in garrison.
Barrel That part of a pipe throughout which the bore and wall thickness remain uniform.
Barrel Bolt A door fastener with a metal rod or bar that runs the case, entering a hole in the jamb. Sizes range from thumb slides to tower blots.
Barrel light A roof light with curved glazing, often in polycarbonate, with similarly curved glazing bars. It resembles a barrel vault
Barrel Nipple A short tubular with a taper thread outside at each end, unthreaded in the middle
Barrel Vault Semicircular arch, ceiling or roof; simplest type of roof.
Barricade A temporary fortification raised to block a street, an obstruction, to fortify.
Barrier A limit or boundary, a fence or other structure to bar passage, prevent access, control crowds.
Barrier Effect The formation of a thin film on a surface, protecting a material from further corrosion
Barrow Run A temporary path for loaded wheelbarrows over soft ground or across floor joints, usually made by laying a series of scaffold boards
Barsati Habitable room/ rooms on the roof of the building with or without toilets, kitchen.
Bartisan A parapet or battlement.
Barytes A heavy aggregate used in barium plaster (Barium Sulphate)

1) The lowest part of a wall or column, which may be widened into a moulding or plinth on top of the footings

2) A pad footing or a machine base

3) The surface over which a finishing is applied, such as granolithic on a stair tread as a base for vinyl tiles or a screed as a base for a topping.

4) The main ingredient of a product; for paint, either its main pigment or the main part of the medium (water based emulsion)

Base Course The lowest course of a brickwork or blockwork wall, laid on top of the foundation. The top may be
Base Exchange A water softening process in which water passes through a mains pressure tank containing zeolite, a mineral reagent, to absorb the salts which harden the water.
Base Gusset A stiffening rib between a baseplate and a steel column
Base Moulding A moulding at the top of a base, where it narrows into a wall or column, often acting as a weathering
Base Sheet A Bitumen felt fixed down to a substrate, such as decking, and bonded to a intermediate sheets of built up roofing
Base Slab A concrete slab under a structure, or a raft foundation
Base Tie A small folded steel channel, bar etc. across the bottom of a pressed metal doorframe to hold the jambs at the correct spacing while the wall is built. It may be removed or covered by floor screed
Basement or Cellar The lower storey of the building below or partly below the ground level.
Basement Wall Either the wall round a basement or a sleeper wall supporting the floor
Baseplate, Stanchion base

1) A thick steel plate on the bottom of a steel column, with holes for holding down bolts. It may have base gussets

2) A bearing plate on the end of a prop. Or jack, e.g. for an access floor

Basilica In Roman and early Christian architecture, a rectangular building supported internally with double colonnades and with a semicircular apse at one end.
Basin Mixer A mixer for a basin either a monobloc type for a single taphole basin or a combination type for a three taphole basin
Basin, Washbasin A sanitary fitting for washing and rinsing the hands
Basketweave Pattern A wood finishing with the grain in neighboring squares alternately in directions at right angles to each other
Bat A rectangular panel of insulation covered with paper, made to fit between the studs of an external wall or between the joists of a ceiling
Batch One mixing of concrete, mortar, plaster etc
Batch Box A bottomless box filled with each constituent of a mix, then lifted away to leave the mix on the mixing platform.
Bath A sanitary fitting, usually with a full-length tub and edge roll round the rim. Domestic baths are made from cast acrylic sheet, cast iron sheet or a steel sheet
Bath Mixer A water fitting to blend hot and cold water for a bath
Bath Panel A rectangle of building board, slab etc to conceal the underside of a bath, from the rim down to the floor, often with toe recess.
Bathroom Pod A factory finished bathroom/toilet module, with its own roof and cladding. It can be placed on a prepared slab by crane and can be connected to services within a few hours
Batten A small Section, normally of timber, to which sheet materials, slates and roof tiles are fixed
Batten Door A matchboarded door
Batten Roll A wood roll
Battenboard A building board with a core of wooden battens and wood veneer facings, bonded together with resin adhesive
Battening Common grounds fixed to wall as a base for a dry lining
Batter An artificial, uniform, steep slope or its inclination, expressed as one horizontal to so many vertical units
Batter Peg A peg driven into the ground to show the limits of an earth slope
Batting Surfacing soft stone with a broad chisel in parallel strokes, giving a regular pattern of fluted cuts
Bauhaus German design school founded in Weimar in 1906 and named by Walter Gropius in 1919. Its philosophy was austere functionalism - no ornamentation - and the use of industrial materials and inter disciplinary methods and techniques.
Baulk A piece of square sawed or hewn timber of equal or nearly equal cross sectional dimensions
Bay One of several uniform divisions of a building, such as the space enclosed between 4 columns or 2 beams.
Bay Window A window formed in a projection of a wall beyond its general line and carried on its own foundation, unlike an oriel. If curved it is a bow window

Ba - Ba
Bb - Bl
Bm - Br
Bs - Bz