AGGREGATE - a mixture of sand and stone, and a major component of concrete.

AIRBRICK - a perforated brick built into a wall for providing ventilation. Used, for instance, to ventilate the underside of timber ground floors, blocked fireplaces or a roof space.

ANGLE BEAD - available in stainless steel, galvanised steel or pvc (2.4mtr, 2.5mtr or 3mtr lengths) they are used to provide a true, straight corner which protects and reinforces a 2 or 3 coat plaster or render application in its most vulnerable area.

ARCH - a curved structure built to distribute weight over an opening in a wall.

ARCHITRAVE - a moulding around a doorway or window opening. It usually covers the joints between the frame and the wall finish, thus hiding any shrinkage gaps which may occur.

ARRIS - the sharp external edge where two surfaces meet at a point.

ASBESTOS - material used in the past for insulation and fire protection. Can be a health hazard. Specialist advice should be sought if asbestos is found.

ASBESTOS CEMENT - cement mixed with up to 15% asbestos fibre as reinforcement. Typically used in roofing, rainwater goods fire-proof linings and various other claddings and linings. It is fragile and will not usually bear heavy weights. Hazardous fibres may be released if cut or drilled.

ASPHALT - black, tar-like substance, designed to be impervious to moisture. Used on flat roofs and floors.

BALANCED FLUE - a "room sealed flue", normally serving gas appliances, which allows air to be drawn to the appliance from outside whilst also allowing fumes to escape.

BALLVALVE (BALLCOCK) - valve operated by a ball floating in a cistern.

BALUSTER - a post or vertical pillar supporting a handrail or parapet rail.

BALUSTRADE - a row of balusters, or other infilling, below a handrail on a landing, stair or parapet.

BARGEBOARD - timber, sometimes decorative, placed along the verge of a roof at a gable end.

BATTEN - thin strips of timber, commonly used to support roof tiles or slates.

BAY WINDOW - a window formed in a projection of a wall and carried on foundations.

BEAM - a structural component spanning an opening and designed to carry the weight of the structure above. Usually concrete or steel in newer constructions. Often timber in older buildings.

BELLCAST - thickening out of render, in a curved shape, to form a drip to deflect water. Usually found at the base of a wall, above the damp-proof course.

BENCHING - shaped concrete slope beside drainage channel within an inspection chamber. Also known as "haunching".

BIBTAP - a hose union bibtap is essentially an outside tap used in the garden to connect hosepipes.

BINDER - a length of wood used to provide cross bracing to a set of roof trusses. Also describes the roof member spanning across ceiling joists to provide improved support.

BIRDSMOUTH - a joint or notch cut into a timber (typically a rafter) where it connects with another timber.

BITUMEN - black, sticky substance, similar to asphalt. Used in sealants, mineral felts and damp-proof courses.

BLISTERING - trapped air bubbles below felt, asphalt or painted surfaces usually indicating imminent failure of the material.

BLOWN - this refers to plaster that has come away from internal walls. This can happen over time as the plaster dries out, or if it was incorrectly applies to the wall.

BOND - the regular arrangements of bricks, blocks or stones in a wall so that the units may be joined together. The principal types of bond used in domestic construction are English, Flemish, header, stretcher, rat-trap, diagonal or garden wall bond.

BRACE - diagonal support in a timber door.

BRACING - the arrangement of timbers spanning across roof trusses to provide lateral stability.

BREEZE BLOCKS - commonly refers to various types of concrete building blocks.

BRESSUMER - a lintel, often timber, over an opening such as a fireplace or bay.

BRITISH STANDARDS - standards produced by the BSI Group to ensure quality of British goods and services. Products and services which the BSI certifies as having met the requirements of specific standards within designated schemes are awarded the kitemark.

BUILDING PAPER - a general term for papers, felts, and similar sheet materials used in buildings, comes in long rolls.

BUILDING REGULATIONS - a list of policies that must be complied to on building projects, covering areas such as structure, fire safety, site preparation, ventilation and drainage.

BUTTRESS - a brick or stone support to a wall designed to resist lateral movement.

CANTILEVER - this is a beam anchored at only one end. It allows for overhanging structures without external bracing. They are widely used in the construction of cantilever bridges and balconies.

CAPPING - the weather-proof finish formed with tiles, or stone or concrete copings, over a wall, parapet or chimney.

CARBONATION - a natural process affecting the outer layer of concrete. Metal reinforcement within that layer is liable to early corrosion, with consequent fracturing of the concrete in some cases.

CASEMENT - a window composed of hinged, pivoted or fixed sashes.

CAVITY TRAY - a moisture barrier inserted above a window or door opening to deflect moisture that transfers across the outer leaf of brickwork back to the outer face rather than letting it cross the cavity at lintel level causing dampness internally. In many cases, the lintel itself acts as a cavity tray though this arrangement is not always appropriate.

CAVITY WALL - traditional modern method of building external walls of houses comprising two leaves of brick or blockwork usually separated by a gap ("cavity") of about 50mm (2 inches) and held together with metal ties. The cavity is then  usually insulated.

CEMENT FIBREBOARD - a combination of cement and reinforcing fibres, it comes in sheet form, most commonly 2400mm x 1200mm and 1200mm x 800mm, and either 6mm or 12mm thick. Its most commonly used as a tile backing board due to its resistance to moisture. Its not actually waterproof, but it does not absorb moisture and has excellant drying properties. One disadvantage is that it is quite heavy!

CEMENT FILLET - a weatherproofing joint between roof slopes and abutting brickwork such as walls or chimneys.

CESSPIT - a simple method of drainage comprising a watertight holding tank, which needs frequent emptying. Not to be confused with "septic tank".

CHASE - to cut into plaster, brickwork etc. to receive cables and pipes.

CHIPBOARD - often referred to as "particleboard". Chips of wood compressed and glued into sheet form. cheap method of decking to flat roofs, floors and (with Formica or melamine surface) furniture and kitchen units.

CISTERN - the part of the toilet which holds the correct amount of water that is required to flush the toilet. They have a handle or a button on them which is pressed or turned to activate the flush. Most toilets nowadays are close coupled, where the cistern is mounted directly onto the toilet bowl, eliminating the need for a long connecting pipe.

CLS - stands for Canadian Lumber Standard, it is timber that has been rounded on all four sides and kiln dried. Ideal for using to build internal stud walls, comes in various sizes and lengths.

COLLAR - a horizontal tie beam of a roof, which is joined to opposing rafters at a level above that of the wall plates, designed to restrain opposing roof slopes. Absence, removal or weakening can lead to roof spread.

COMBINATION BOILER - a central heating boiler that also provides hot water "instantaneously" on demand, usually within a pressurised system. With this form of boiler there is no need for water storage tanks, hot water cylinders etc.

CONDUIT - usually a metal or plastic tube used to protect electrical cables.

COPING/COPING STONE - usually stone or concrete laid on top of a wall as a decorative finish and designed to stop rainwater soaking into the wall.

CORBEL - projection of stone, brick, timber or metal jutting out from a wall to support a weight above.

CORNICE - a moulding at the junction between a wall and ceiling. Can also include a moulding at the top of an outside wall designed to project and throw raindrops clear of the wall.

COURSE - horizontal layer of bricks, blocks or slate.

COVING - curved junction between wall and ceiling ie. a type of cornice.

COWL - a terminal to a flue pipe to aid discharge of gases and exclude the weather.

CREASING - projecting course of tiles to a wall or chimney to prevent rain from running down the face of the brickwork.

CRUCK BEAMS - pairs of curved timbers in period buildings which run from ground level and meet at the ridge.

CUPOLA - a dome or lantern shaped feature built on top of a roof.

DADO - the bottom one metre or so of wall clad with timber, originally designed to provide protection to the wall, and also covering the area likely to be affected by rising damp. The top edge is finished with a Dado Rail.

DAMP-PROOF COURSE - layer of impervious material (bitumen felt, PVC, slate etc.) incorporated into a wall and designed to prevent dampness rising up the wall, and lateral dampness penetrating around windows, doors etc. Various alternative methods are available for damp-proofing existing walls including "electro-osmosis" and chemical injection.

DAMP-PROOF MEMBRANE - horizontal layer of impervious material (usually polythene or bitumen) incorporated into floors or slabs.

DORMER - a construction with a window that projects from a sloping roof.

DOT AND DAB - also known as drywall adhesive or bonding compound, it is a powder adhesive used to stick sheets of plasterboard to walls.

DRY ROT - (serpula lacrymans) a very serious form of fungus that attacks structural and joinery timbers, often with devastating results. Flourishes in moist, unventilated areas, but the spores can survive in dry conditions.

EAVES - the lower edge of a roof.

EFFLORESCENCE - powdery white salts crystallized on the surface of a wall as a result of moisture evaporation.

ENGINEERING BRICK - particularly strong and dense type of brick, often used as a damp proof course in older buildings.

ENGLISH BOND - brickwork with alternating courses of headers and stretchers.

FASCIA - a board fixed to the rafter ends along the roof eaves.

FIBREBOARD - cheap, lightweight board material of little strength, used in ceilings or as insulation to attics. Considered to be a fire risk.

FILLET - a thin strip of wood, cement, slate tec. used to fill a narrow joint.

FLASHING - a sheet cover formed over a joint, such as between a roof covering and a chimney or wall, to render it waterproof. Normally formed in metal (lead, zinc, copper) or cement.

FLAUNCHING - a mortar weathering on the top of a chimney stack surrounding the base of the chimney pots to throw off the rain and thus prevent it from saturating the stack.

FLEMISH BOND - brickwork with alternating headers and stretchers in each course.

FLUE - a smoke duct in a chimney, or a proprietary pipe serving a heat producing appliance such as a central heating boiler.

FOOTINGS - older, usually shallow, form or foundation of brick or stone.

FOUNDATIONS - normally concrete, laid underground as a structural base to a wall. In older buildings these may be brick or stone.

FURNITURE - in building terms, the handles, knobs, locks etc. fitted to doors and windows.

GABLE - upper section of a wall, usually triangular in shape, at each end of a ridged roof.

GROUT - used for filling the joints between wall and floor tiles.

GULLY - an opening into which rain and waste water are collected before entering the drain.

GUTTER - a channel along the eaves of a roof or the edge of a path for the removal of rainwater.

HARDCORE - broken bricks or stone which, consolidated, are used as a base under floors and patios.

HEADER - a brick laid end on.

HEAVE - swelling of clay sub-soil due to the presence of moisture. Can cause an upward movement of floors or foundations in extreme cases.

HIP - the sloping angle where two roof planes meet to form a ridge.

HIP TILE - a saddle shaped, angular or half round tile fitting over the junction of the roof slopes at a hip.

HOPPER HEAD - an open funnel or hopper shaped head at the top of a rain or waste pipe to collect rainwater and/or waste from one or more pipes.

IN SITU - describing work done in the place where it is finally required, e.g. concrete may be pre-cast offsite in sections which are later taken to the position where they are required, or it may be cast 'in situ' on the site itself.

INSPECTION CHAMBER - commonly called a manhole. An access point to a drain comprising a chamber (of brick, concrete or plastic) with the drainage channel at its base and a removable cover at ground level.

INTERLOCKING TILES - tiles which lock together to form a watertight roof with only minimal lapping.

INVERT - the lowest part of a drain.

JAMB - vertical side of a doorway or window.

JOINTING - the mortar bedding between bricks or stones.

JOIST - a timber or steel beam directly supporting a floor or ceiling.

KEY - the roughness of a surface which provides a bond for any application of paint, plaster, render, tiles etc, or spaces between laths or wire meshes which provide a grip for plaster.

KNOTTING - a liquid applied to knots in softwood prior to painting to prevent them showing through at a later date.

LAP - the overlap of slates, tiles and other coverings.

LATH - any base for plasterwork; typically thin wooden strips or expanded metal.

LEDGED - a method of door construction whereby the vertical boards are fixed together with horizontal members (ledges). The strongest design will be ledged, braced and framed but all combinations are found.

LINING - the wood finish to a window or door jamb.

LINTEL - a horizontal beam over a door or window opening usually carrying the load of the wall above. Often lintels can be partially or completely hidden from view.

LOFT BOARDS - also known as V313 or chipboard flooring, available in a number of board sizes such as 2.4mtr x 0.6mtr or 1.2mtr x 0.32mtr, and either 18mm or 22mm thick. They are tongue and grooved on the edges for rapid and easy installation in the loft, and have a smooth finish.

LOUVRE - slats laid at an angle incorporated into a door or window. Can be hinged to allow ventilation/light.

MANSARD - a roof made with slopes of different pitches, usually providing an upper floor of useable space within a roof structure.

MASTIC - a generic term for any sealant used in the building process.

MATCHBOARD - a board that has a groove cut into one edge and a tongue cut into the other so they fit tightly together (we use this term to describe a type of door found in some period buildings).

MDF - medium density fibreboard.

MEZZANINE - a floor between the ground and first floors, often accessed off a half landing.

MORTAR - mixture of sand, cement (or lime), and water used to join stones, blocks or bricks, and for pointing and general filling.

MULLION - vertical bar dividing individual lights in a window.

NEWEL - post supporting a staircase handrail at top and bottom. Also, the central pillar of a winding spiral staircase.

OGEE - a specific shape where a concave arc flows into a convex arc. An ogee gutter has particular profile, is uaually formed in cast iron, and is still very common in Victorian housing.

ORIEL - a projecting structure, normally a window.

OSB BOARD - stands forOriented Strand Board. Its formed by layering strands of wood in specific orientations and adding adhesive. Its also  known as Sterling Board, and is commonly used as sheathing in walls and flooring, and also in timber frame houses and for flat roofs.

OVERSAILING - a projecting course of brickwork, either a feature of the construction, or resulting from structural movement.

OVERSITE - the finish to the ground surface beneath suspended floors.

PANTILE - a curved roof tile which hooks over adjoining tiles, typical in some 1930s construction.

PARAPET - low wall along the edge of a roof or balcony, or extending over the roof slopes above a party or gable wall.

PARGING - plaster finish to the inside of a chimney flue.

PARTY WALL - the wall which seperates, but is shared by, adjoining properties.

PEDIMENT - a low pitched gable.

PIER - a vertical column of brickwork or other material, used to strengthen the wall or to support a weight.

PITCH - the angle of slope to a roof.

PLANED ALL ROUND (PAR) - is wood that has all its flat surfaces, edges and sides, planed up.

PLANED SQUARE EDGE (PSE) - is wood that has one edge planed straight.

PLASTERBOARD - sandwich of plaster between paper. Commonly used for ceilings and partition walls.

PLINTH - the projecting base of a wall.

PLYWOOD - board made from veneers of wood glued with the grain laid at right angles.

POINTING - outer edge of mortar joint between bricks, stones etc.

PURLIN - horizontal beam in a roof providing intermediate support to the rafters.

PVCu - unplasticised polyvinyl chloride. Used in window frames and replacement eaves.

QUOIN - the external angle of a building, or bricks or stone blocks forming that angle.

RAFTER - a sloping roof beam, usually timber, forming the carcass of a roof.

RAIL - a horizontal part of a door frame or window.

RAKED - pitched, sloping.

RELIEVING ARCH - an additional arch over a lintel.

RENDER - smooth or rough cast cement or lime based covering to a wall, either internally or externally, sometimes with pebbledash or other textured finish.

RETAINING WALL - a wall built to hold back a bank of soil.

REVEAL - the side or top faces of a window or door opening.

RIDGE - the highest part or apex of a roof where two slopes meet.

RIDGE TILE - a specially shaped angular or half round tile for covering and making weather-tight the ridge of a roof.

RISER - the vertical part of a step or stair.

RISING DAMP - moisture soaking up a wall from the ground by capillary action.

RSJ - rolled steel joist.

ROUGH CAST - a rough render finish to external walls.

SARKING - felt used as an underlining to a roof.

SASH - the frame of a window that holds the glass.

SCREED - a smooth final surface of a substance, such as concrete, that is applied to a floor, on top of which other finishing materials can be applied.

SCRIM - a self adhesive polyester tape material that is used to reinforce plaster to prevent cracking. Comes in a roll, its typically used where plasterboards join together.

SEPTIC TANK - private drainage installation whereby sewage is collected into a chamber and decomposes through the action of bacteria, with remaining solids requiring removal periodically, and liquids running off to a water course or soakaway.

SETTLEMENT - downward movement resulting from failure of the components of the building, normally the foundations. All properties settle to some extent, and this can show as cracking and/or distortion in walls. Very often minor settlement is not of great significance to the building as a whole.

SHAKE - a naturally occuring crack in timber. Shakes can appear quite dramatic, but strength is not always impaired.

SHIPLAP - horizontal external boarding, usually timber or upvc.

SHINGLES - small rectangular tiles of wood (often cedar) used on roofs instead of tiles, slates etc. Sometimes also used to face walls.

SHUTTERING PLY - non-structural low cost plywood, suitable for numerous uses such as shuttering when pouring concrete, roofs, sheds and boarding up. Readily available in 2.4mtr x 1.2mtr sheets (or 8' x 4' in old money) that are 9mm, 12mm or 18mm thick.

SKIM BEAD - also known as thin coat angle bead, or minimesh plasterbead, its available in galvanised, pvc or stainless steel lengths. They are used to reinforce and protect one-coat finishing plaster on corners and reveals on internal walls and plasterboard.

SKIMMING - using a finishing plaster on new plasterboard or on existing walls to create a smooth finish.

SKIM STOP BEADS - also called plasterstop beads, they are galvanised in 2.4 or 3metre lengths with a 3mm stop. They are for a neat 3mm finish on plasterboard and smooth backgrounds. They greatly reduce the time in forming end stops, and finishes and reinforces the edges of thin coat plaster.

SKYLIGHT - a window set into a roof slope.

SOAKAWAY - a pit, filled with broken stones etc., below ground to take drainage from rainwater pipes or land drains and allow it to disperse.

SOAKER - piece of flexible metal fitted to interlock with slates or tiles and make a watertight joint between a wall and a roof or at a hip or valley. Flashings are used over the soakers at a joint against a wall or chimney.

SOFFIT - the underside of an arch, beam, staircase, eaves or other feature of a building.

SOIL PIPE - a vertical pipe that conveys sewage to the drains. Its upper end is usually vented above the eaves.

SOLDIER COURSE - a horizontal course of bricks set on end over a window or door opening.

SPALL - splitting of masonry, tiles, concrete etc., usually due to the freezing and expansion of trapped water.

STOP BEADS - available in galvanised steel, stainless steel or pvc lengths, with various different sizes of stop like 8mm, 10mm, 13mm, 15mm and 20mm. They are used to provide a precise, straight, clean finish and also reinforce 2 or 3 coat plaster or render on its edge.

STOP COCK - a valve on a gas or water supply pipe which is used to cut off the supply.

STOP END - the end piece of a gutter.

STUD WALL - lightweight wall construction comprising a framework of timber faced with plaster, plasterboard or other finish.

STRETCHER - a brick or block laid lengthways.

STRING - the sloping board to which the steps of a staircase are attached.

STRING COURSE - a course of brickwork that projects beyond the face of an external wall.

STRUT - a support, usually to a purlin.

SUB-SOIL - soil lying immediatelybelow the topsoil.

TANALISED - timber which has been impregnated with a preservative solution to protect the timber against decay.

TIE BAR - metal bar passing through a wall, or walls, in an attempt to brace a structure suffering from structural instability, normally lateral.

TINGLES - strips of lead or other metal used to hold slipped slates in position.

TORCHING - mortar applied on the underside of roof tiles or slates to help prevent moisture penetration. Not necessary when a roof is underlined with felt.

TRANSOM - horizontal bar of wood or stone across a window or top of door.

TREAD - the horizontal part of a step or stair.

TRIMMED JOIST - cut joist where an opening is formed in a ceiling, roof or floor, for example a roof hatch or stairwell.

TRUSS - a prefabricated triangular framework of timbers used in most modern roof constructions.

UNDERLINING - a lining of felt, PVC, or similar, laid over the rafters and beneath the tiles and battens, to provide a second line of defence to a roof against weather penetration.

UNDERPINNING - method of strengthening weak foundations whereby a new, stronger foundation is placed beneath the original.

VAC VAC - a way of treating timber by sealing it in a chamber and using a vacuum to remove all the air from the timber. A preservative is then applied, before the vacuum is applied again to remove any excess preservative.

VALLEY GUTTER - horizontal or sloping channel, usually lead or tile lined, at the internal intersection between two roof slopes.

VERGE - the edge of the roof, especially over a gable, or around a dormer window or skylight.

WALL PLATE - timber normally fixed on top of a wall to receive floor joists or roof rafters.

WALL TIE - usually a piece of metal bedded into the inner and outer leaves of a cavity wall to provide a physical connection between the two.

WASTE PIPE - a pipe from a wash hand basin, sink or bath to carry away the waste water into the drains.

WBP - stands for weather and boil proof, and refers to the glue used in making sheets of plywood. It is an exterior grade plywood,  thus meaning it can be used outside.

WEATHERBOARD - a board fixed externally to the bottom of a door to exclude driving rain.

WEEPHOLE - a small drain hole or gap in brickwork formed to allow the escape of water.

WOODWORM - colloquial term for beetle infestation, usually intended to mean Common Furniture Beetle, by far the most frequently encountered insect attack in structural and joinery timbers. The wood is attacked by the larvae of the beetle.