Jargon Buster - Letter C

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Came
A grooved strip of lead which binds glass into a leaded light or stained-glass window.

Carbonation
A natural process affecting the outer layer of concrete, caused by the corrosion of metals within that layer.

Casing
The timber or concrete lining of a door or window opening.

Cavity Wall
The continuous gap between the inner and outer brickwork usually 50mm in width. Also known as Hollow Wall.

Cavity Wall Insulation
Insulation of wall cavities with material such as polystyrene beads, foam or Rockwool.

Cavity Wall Tie
Metal ties which are bedded into the inner and outer sections of cavity walls to strengthen it.

Cesspool
A simple method of drain which is just a holding tank that needs frequent emptying. See also Septic Tank.

Chamfer
A narrow angled corner (typically at 45 degrees to adjacent surfaces); to plane the angled corner.

Chase
A groove cut in masonry or plaster in which pipe-work or an electrical cable may be placed; to cut or channel such grooves.

Chipboard
Chips of wood compressed and glued into sheet form. A cheap way of decking flat roofs and floors and (with Formica or melamine surface) used for furniture, especially kitchen units.

Circuit
A complete path through which an electric current can flow.

Cistern
Tank for storing water - usually located in the attic.

Cleat
A cable fixing e.g. for telephone wires.

Collar
Horizontal timber beam which restrains opposing roof slopes. Used to prevent 'Roof Spread'.

Combination Boiler
Modern type of gas boiler which heats water on demand, so that there is no need for water storage tanks, hot water cylinders etc. Generally the pressure is much better than other types of boiler for showers.

Concave
An inward curve.

Condensation
Occurs when warm moist air meets a cold surface. The water in the air then either appears as drops of water on the surface (e.g. on windows), or if the surface is absorbent, it soaks into the surface and is often not noticed unless or until rot/mould appears. (See also Ventilation).

Conductor
A length of wire, along which an electric current will pass.

Contract
A written or verbal agreement between a client and a building contractor to do certain types of works.

Contractor
The person who signs the contract and undertakes the specified works.

Convex
Curving outwards.

Coping / Coping Stone
A stone or concrete layer, laid on top of a wall as a decorative finish and to stop rainwater soaking into the wall.

Corbell
Stone, brick, timber or metal jutting out from a wall to support a weight.

CORGI
Confederation for the Registration of Gas Installers. Gas pipe work must usually be installed by a CORGI registered fitter.

Cornice
Ornamental piece of moulding around the top of a building or around the wall of a room just below the ceiling. External cornices throw rain water away from the wall of a building and also protect the roof from fire.

Counterbore / Countersink
A hole which allows the head of a bolt or screw to lie below a surface.

Coving / Cornice
Curved junction between wall and ceiling.

Cup
The natural bend across the width of a timber, caused by shrinkage.