ARCHITECTURAL DICTIONARY                

Your Handbook for understanding Architecture:


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Board Measure The superficial measurement of a quantity of timber
Board-finish plaster Usually a low expansion retarded hemihydrate plaster, suitable for single coat finishing work on true surface such as gypsum plasterboard. It is one of the few plasters to which lime should never be added
Boarding Joists Common Joists for floorboarding
Boarding, sheathing boards Boards laid side by side
Boasted Ashlar A rough finish to stonework made by boasting
Boaster A mason's boasting chisel, 40 to 80 mm wide, struck by a mallet in dressing stone
Boasting The hand wasting or rough dressing of the surface with oblique or vertical strokes, which are usually not uniform, from a boaster
Boil resistant adhesive An adhesive with good water resistance, able to withstand hot water for many years also attracts by insects and fungi
Boiler A water heater in which the water should not boil. A boiler is used for the production of domestic hot water and hot water for central heating
Boiler House A plantroom for housing boilers
Bolster A broad based steel brick layer's chisel with a blade about 110 mm wide
Bolt

1) A fastener with a head and screw thread, for a nut

2) The tongue of the lock that prevents the door opening when it is out (thrown) and allows it to open when withdrawn

3) Hardware to hold door or shutter closed, usually with direct or simple action

Bolt Box Formwork round foundation holding down bolts for structure steelwork, to make a pocket in the concrete. During Concreting the bolts may move out of position by up to 20 mm. After the concrete hardens steelwork is erected, with the bolts passing through holes in each baseplate. The pocket formed by the bolt box allows the baseplate to be moved into its right place. Later the bolt boxes are grouted
Bolt Croppers A pair of hand shears used for cutting bolts or steel rods
Bond The layout of courses of bricks or blocks in a wall. It is important to keep every vertical joint at least a quarter length of a brick or stone from the next vertical joint above or below, using bats and closers.
Bond Beam A reinforced concrete beam made inside a course of hollow blockwork from which the block ends and internal walls have been removed. The beam ties the wall together
Bond Course A course of headers in a brickwork or blockwork wall
Bonding The use of high strength adhesive usually thermosetting resins, elstomers or thermoplastics to make permanent structural joints, composite metal members, prefabricated building panels etc.
Bonding compound Hot molten blown bitumen put on to a roof to stick layers of built-up roofing together. A sealing compound is similar but is applied cold
Bonding Plaster A pre-mixed light weight gypsum plaster containing exfoliated vermiculite, used as the undercoat in two-coat work on surfaces difficult to bond, such as smooth formed concrete walls
Bonding Tape Tape glued on both faces for joining sheet materials in damp-proof courses, vapour barriers (to control humidity, smell etc). The tapes could be of bitumen felt, polyethylene
Bonding Treatment Any treatment of a surface before the application of a finish (paint, plaster) so that it will stick. E.g. Roughing up the wall surface before plastering
Boning The use of T shaped rods for setting out a flat surface, for excavations, ground slabs, drain laying etc.
Boning Pegs Small hardwood pegs that are placed at the edges of large stones to be dressed flat, used with winding strips as guides
Boom The jib of a crane, the dipper arm of a backhoe
Booster

1) A pump for increasing the pressure in a water supply pipe or fire riser.

2) A heating element in an electric storage water heater which is switched on during the day if the draw-off temperature drops too low

Boot A step down formed in the edge of a concrete floor slab (or a beam or lintel) to carry the outer skin of a cavity wall. This allows a drop in the damproof course to drain rainwater outwards through weepholes in the facing brickwork. The movement joint under the boot is weatherproofed with a sealant and the boot's outside face may be concealed with brick slips
Boot Lintel A lintel across a door or window opening, with a boot
Booth A small room or cubicle, for privacy or isolation, often with sound insulation
Bore

1) To pierce so as to form a hole.

2) To drill a hole, or the hole after it is drilled

3) The internal diameter of a hole or a pipe. Copper pipe for water supply is mainly Microbore

Bore Lock ( Key-in-knob set, tubular mortice) A door lock with a tubular T-shaped case. It fits into a bored mortice made with a hole saw from the face and with a drill from the stile, which is easier than cutting a rectangular mortice
Borer (Woodworm) Wood-boring beetles in the larval phase, which burrow into timber for food and shelter, leaving behind wormholes when they emerge as adults e.g. furniture beetle, longhorn beetle etc. Treatment against attack using preservatives usually does not penetrate deeply enough to reach all borers, but they are killed by high temperatures, as in kiln dried timbers
Borosilicate Glass Heat and chemical resistant clear glass made from borax as well as the usual silica, giving complex compounds of sodium borosilicate. It is used in factory shaped and tempered fire resisting glass, as glassfibre, to make vitreous enamel and in glass drain pipes
Bottle Trap A trap on the waste from a kitchen sink or bathroom basin which has a bottle shaped cap that can be removed to clean out any rubbish causing a blockage, such as matches, hairpins and hair. Bottle traps are usually less self cleansing than a tubular S-trap
Bottom Chord The lowest member of truss or girder
Bottom Plate A member along the bottom of a framed partition that spreads the loads from the studs to the supporting floor
Bottom Rail The horizontal bottom member of a framed door, casement or lower sash
Bottom Tie A base tie of a pressed metal door frame
Bottom Ventilation An air inlet for natural ventilation, particularly to a plantroom or machinery enclosure
Bottom-hung window A window with its opening sash hinged at the bottom
Bottoming Hand trimming excavations with a shovel, working behind an excavator such as backhoe, to clean out lumps of dirt and leave a tidy formation
Bottomless hole A hole which passes through a material. It is therefore difficult to make a fixing in it except with a toggle bolt, anchor etc
Boundary The edge of a building site
Bow Window A projecting Bay Window which is curved in Plan
Bowl

1) The part of a sanitary fitting made to contain water, usually with a waste outlet. Kitchen sinks may have one or two bowls. A bowl of a WC is also called the pan

2) A light diffuser over a luminaire, often made from acrylic sheet

Bowl Saw An ancient type of saw with a thin blade held at both ends in a loose H frame and tightened with twisted wire or string
Bowl,urinal, pod A rounded vitreous china urinal, usually rimless and wall hung at varying heights to suit users
Box Cornice The edge of a roof built out to conceal the gutter, with a fascia in front and a soffit board underneath
Box Frame A sash window cased frame
Box Gutter / trough A roof gutter below the general level of the roofing, with a lining in supported sheetmetal roofing, or bitumen roofing felt over a wooden box. Box gutters should always have a safety overflow, such as a scrapper through a parapet, so that if the outlet becomes blocked with leaves or snow, the rainwater will not flood though the ceiling or overload the roof
Boxed Heart The heart centre, usually within a 100 mm square, cut out during the conversion of timber and discarded, This is done with some eucalyptus hardwoods, which have poor heart
Boxing A formwork box, or a casing of building board on ground or studs
Boxwood A hard hardwood used for making chisel handles
BQ,BOQ Bill of quantities
Brace A strut or tie that stabilizes other members, usually placed so that a triangle is formed, e.g. a knee brace, the braces on a matchboard door, temporary braces during construction etc.
Braced Frame A structural timber building frame with widely spaced, heavy posts and beams and girders which carry main loads. It has infill walls, which are non load bearing. Bracing for structural stability comes partly from the joint between the posts and beams, although additional cross-bracing can be concealed in the walls
Bracket A support for a shelf, projecting from a wall.
Bracket Arm An outreach arm
Bracket Lamp A wall-hung Lamp
Bracket Scaffold A scaffold carried on brackets bolted to a wall
Bracketed Stairs Stairs with treads carried on a cut string, usually with overhanging nosings
Brad

1) A wire nail usually 50 to 65 mm long, with rounded built head

2) A cut nail of constant thickness but tapering width, with a square head projecting from one edge only, or an oval-wire brad

Bradder A small nail gun that drives brads up to about 65 mm long
Braided Cable Flexible flat cable made from several strands of bare copper wire plaited together, used for the earth bonding of moving parts, e.g. switchboard doors
Bracket

1) A projecting support usually fixed to a wall or column, Stair handrails are often on metalwork brackets. Pipework can be supported by brackets with two piece cleats

2) A short vertical board fixed to the carriage of a timber stair to support the tread directly

Branch A secondary pipe or cable connected to a main in a distribution or collection system, such as water supply, drainage, sewerage or electrical circuits
Branch Circuit The electrical wiring to power or lighting use points, from the fuses in the distribution board, usually run as either a ring main or a radial circuit
Branch Manhole A manhole in which a branch connection is made
Branch Pipe, discharge pipe A branch to carry soil water or waste water to the stack
Branch Vent A pipe which admits air to the downstream side of the water seal in a trap the start of a drain. Usually it is run upwards to the stack vent, which lets in air through its top end. The branch vent prevents unsealing of the trap as a flush of water passes down the soil stack, e.g. as in a one-pipe system of sanitary pipework
Brash timber, Brashy Timber which breaks with small resistance to shock and little or no splintering. This short grain may be due to fungus
Brass A metal alloy made from a mixture of copper and zinc, often with small amounts of nickel, lead iron, etc, used in traditional builder's hardware and some pipe fittings. Brasses are mostly easily formed, strong and corrosion resistant, but are best not used with other metals, which could cause dezincification
Brazilian Mahogany True Mahogany, a close grained red timber with fine silky texture, hard and very little moisture movement. It is stronger than oak but slightly easier to work and used for best joinery
Brazing A generally simple, inexpensive way of joining metals using a copper- zinc filler metal (hard solder) which melts above 500deg c, normally with an oxy-acetylene flame. The two surfaces need suitable preparation, usually limited to thorough cleaning. A flux is also needed. Brazing, particularly silver brazing, us widely used for capillary joints in copper tube or brass pipe. Brazed steel joints are not as strong as welded ones
Break Draught Damper A flue damper
Break glass unit A manual fire alarm call point with a breakable glass cover.
Break joints Staggered joints
Break out To cut away part of a building fabric to make a secure connection with new work, e.g. the toothing of brickwork or the exposing of reinforcement bars
Breaker A power tool for breaking rocks, concrete or roads by forcefully hammering a pick or similar tool. It can be a hydraulic, pneumatic or electric hand held jackhammer or a mounted backhoe
Breaker Slab A clay or concrete slab in the backfill over buried cables, to indicate their presence, in the same way as a tracer
Breaking Down The first of two stages in conversion of timber, in which the log is sawn into squared flitches
Breaking of seal The unsealing of traps
Breast

1) A projection of a wall into a room, containing the flue and hearth of a fireplace

2) The wall under a window sill, down to the floor

Breast Drill A large hand drill operated with both hands, with an extension and plate for thrust from the user's chest
Breather Hole A tiny hole from the air space between secondary glazing out to the cold side, where the air contains less moisture in winter, even at a higher relative humidity. As atmospheric pressure rises and falls, the air space gradually fills with dryer air, reducing condensation, but dirt and insects may enter unless the holes have a filter e.g. a porous tape
Breather Membrane A building paper that is microporous to allow ventilation and the escape of water vapour. It is put on over the outside of heat insulation and under the external cladding of a timber framed wall (or roof). It also helps prevent driving rain from passing inwards. Breather membranes must be on the 'cold' side of the wall, i.e. on the opposite side of the framing to its vapour barrier
Breech Fitting A junction pipe fitting
Breeching A double inlet to a dry riser accessible from the street
Breeze Block A building Block formerly made with coke breeze from gas works. It is superseded by the clinker block
Breezeway A covered walk between buildings
Bressummer A long heavy Lintel across an opening, to carry the wall above. It is generally not used nowadays. It was usually made of Timber
Brick
A rectangular block usually so sized so that it can be easily held in one hand. They are generally proportioned for the lengths of each side (face, bed and end) to form multiples, forming Bonds. Building bricks vary widely in strength, durability and appearance from the most costly engineering bricks or facing bricks to commons. They are mostly used to build walls and vary in type from solid to frogged, cellular, perforated and hollow. Bricks shaped differently from the normal full brick are called specials.
Brick axe A bricklayer's hammer
Brick Damp Course A damp-proof course in a wall made from two courses of damp-proof course bricks, or engineering bricks with a water absorption of less than 7% laid with staggered joints in 1:1/4:3 cement:lime:sand mortar. The mortar should not carry any plasticizer as this may reduce adhesion. As brick damp courses are more rigid and resist tension better than other types, they are suitable for freestanding walls
Brick Elevator Mobile Contractor's plant used for raising building material to a scaffold. It has a rubber belt and steel cleats to stop brick slipping at steep angles
Brick nogging, brick partition wall Non-Load bearing wall, usually infilling between the columns or a steel framed building. The wall is generally constructed by bricks on edge. Wall ties and movement joints are needed for them
Brick Tie A wall tie
Brick trowel A long tapering triangular trowel held in one hand for bedding and jointing bricks
Brickbat

1) A brick cut across and shorter than full length, used to complete a bond

2) A bat

Bricklayer A person who builds and repairs brickwork (bricklaying), on large projects usually working as part of a gang under a foreman bricklayer
Bricklayer's Hammer A small hammer with sharp cross-peen as well as the striking face, used for breaking and dressing bricks
Bricklayer's Line (Soot) A line used as a guide during bricklaying
Bricklayer's Scaffold A scaffold supported by putlogs, which have a flattened end to fit into raked-out holes in the bed joints, the other end being carried on ledgers held up by the standards
Bricklaying The art of laying bricks in courses to make brickwork by bedding and jointing with cement mortar. Joints are usually shoved and the bricks kept true and plumb by working to a bricklayer's line, which is stretched between profiles
Brick-on-edge Brickwork, usually of headers, laid on edge for a capping or sill
Brickwork A wall made up of courses of bricks laid in mortar according to a bond.
Brickwork Beam A concealed lintel made by inserting reinforcement in bottom bed course of brickwork over an opening, for clear spans upto 2.1 Mt
Brickwork Chaser A power tool that cuts a neat chase in brickwork to receive electrical conduit or a pipe
Bridging

1) The spanning of a gap with common joists

2) The stiffening of adjacent wooden floor joists by a row of solid bridging or herring-bone strutting at right angles to the joists.

Bright

1) A description of freshly sawn timber without discolouration

2) Steel with low surface oxidation

Brilliance

1) The cleanness and brightness of a colour

2) The clearness of a varnish or lacquer; the absence of opalescence and similar defects

Brise Soleil A French term for a permanent sun shade (Horizontal or vertical blades, decorative screen walls) outside an external wall
Broach

1) The pin in the keyhole of lock with a hollow key

2) A pointed mason's chisel used for wasting stone

Broadloom Carpet Fabric floor covering in rolls 2.50 to 4.00 Mt wide.
Broken Bond Brickwork or Blockwork which is not entirely built to format, it has bats in the courses rather than full bricks.
Bronze A hard, corrosion resistant alloy of copper and usually tin, sometimes with other elements
Broom-finish concrete A floor slab that is floated and trowelled smooth, then finished by drawing a stiff broom across it to make it a non slip surface
Brooming Scratching a floating coat with a stiff broom to make a key for plaster, or giving a broom finish to concrete
Brush Paint brushes are made from synthetic fibres or animal bristles (Stiff Hairs) held on to a handle, usually with a metal ring or ferrule. The bristles of larger brushes may be set in synthetic resin
Brush Seal A long Strip of bristles fixed to project from the edge of a door leaf, as a wiping seal for weather-stripping or for smoke control
Brushability The ease with which paint can be applied by brushing. Brushable paints are not gummy, do not cause ropiness and enable a live edge to be easily picked up
Brutalism Functionalist style of the 1950's -60's that left materials such as concrete determinedly undistinguished.


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