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Building Terms

Whilst we endeavour to avoid jargon in our reports, the use of some technical terms is unavoidable. However, if any part of the report we provide is unclear, please contact the surveyor who will be delighted to assist further. The list below is very limited relative to the full extent of building terms in existence, having been deliberately restricted to those which this particular practice employs in its survey reports.

Addition   A projecting structure, or wing, which is part of the original building rather than a subsequent extension.

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.

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 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.

Back Addition    The narrower part of a building, or wing, which extends rearwards beyond the “main“ structure, being an original feature rather than a subsequent extension. This is sometimes called an “outrigger“ in different parts of the country.

Back Gutter    The lining and flashing arrangement at the back of a chimney stack (on the upslope side) to divert rainwater away from the stack.

Bargeboard    Timber, sometimes decorative, placed along the verge of a roof at a gable end.

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.

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.

Batten    Thin strips of timber, commonly used to support roof tiles or slates.

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".

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.

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

Bressumer    A lintel, often timber, over an opening such as a fireplace or bay.

Buttress    A brick or stone support to a wall designed to resist lateral movement.

Cames    The lead bars in leaded light windows.

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

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 5Omm (2 inches).

Cement Fillet    A weatherproofing joint between roof slopes and abutting brickwork such as walls or chimneys.

Cesspool (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.

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.

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.

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 most 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.

Deathwatch Beetle    (Xestobium rufovillosum). Extremely serious insect pest that attacks structural timbers. Usually affects old hardwoods with fungal decay already present.

Dormer    A construction with a window that projects from a sloping roof.

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 etc. used to fill a narrow joint.

Flank wall    A side wall.

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.

French Casement    A pair of sashes the height of a door and hinged to serve as a door and window.

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.

Hygroscopic    The ability to absorb moisture from the atmosphere.

In Situ    Describing work done in the place where it is finally required, e.g. concrete may be pre-cast off site 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.

Landslip    Downhill movement of unstable earth, clay, rock etc often following prolonged heavy rain or coastal erosion, but sometimes due to sub-soil having inherently poor cohesion.

Lantern Light    A roof light constructed like a lantern with fixed and/or opening glazing.

Lap    The overlap of slates, tiles and other coverings.

Lath    Any base for plasterwork; typically thin wooden strips or expanded metal.

Lean-to    A structure, the sloping roof of which abuts a higher wall.

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.

Louvre    Slats laid at an angle incorporated into a door or window. Can be hinged to allow ventilation/light.

Longhorn Beetle     (Hylotrupes Bajulus). A serious insect pest mainly confined to the south-east of England, which can totally destroy the structural strength of wood.

LPG    Liquid Petroleum Gas or Propane. Available to serve gas appliances in areas without mains gas. Requires a storage tank.

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 usually formed in cast iron, and is still very common in Victorian housing.

Oriel    A projecting structure, normally a window.

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 1930 s construction.

Parapet    Low wall along the edge of a roof or balcony, or extending over the roof slopes above a party or gable wall.

Parapet Gutter    A gutter behind a parapet usually provided with a flexible metal or other impervious lining.

Parging    Plaster finish to the inside of a chimney flue.

Party Wall    The wall which separates, 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.

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 (uPVC)    Unplasticized polyvinyl chloride. Used in window frames and replacement eaves.

Quoin    The external angle of a building, or bricks or stone blocks forming that angle.

Racking    The distortion, or tendency to distort, laterally as in changing a rectangle to a non-rectangular parallelogram.

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    Final smooth finish of a solid floor; usually cement or concrete.

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.

Sewer    A large, underground pipe or drain used for conveying waste water and sewage. The Local Authority is usually responsible for the sewers, which collect the effluent from various drains, the drains being the responsibility of the land owners.

Shake     A naturally occurring crack in timber. Shakes can appear quite dramatic, but strength is not always impaired.

Shiplap    Horizontal external boarding, usually timber or PVCu.

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

Skeiling    The raked (angled) part of a ceiling sometimes found at the perimeter of a top floor room, being the plastered underside of the principal roof rafters. This occurs where the ceilings are set at a level higher than the tops of the external walls.

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 it 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 (frost damage).

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.

Subsidence    Downward movement resulting from failure in the ground.

Sub-Soil    Soil lying immediately below the topsoil.

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.

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.

Weatherboard    A board fixed externally to the bottom of a door to exclude driving rain.

Wet Rot    (Coniophora puteana et al.). Decay of timber due to damp conditions. Not to be confused with the more serious dry rot.

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 (Anobium punctatum), by far the most frequently encountered insect attack in structural and joinery timbers. The wood is attacked by the larvae of the beetle.

Michael Roberts and Associates, Chartered Surveyors, carries out surveys (Building Surveys and Homebuyer Surveys) in the following areas of Berkshire, Buckinghamshire, Hampshire and Oxfordshire:

Arborfield, Binfield, Bracknell, Burghfield, Camberley, Caversham, Crowthorne, Earley, Eversley, Finchampstead, Henley, Maidenhead, Marlow, Mortimer, Pangbourne, Reading, Sandhurst, Shiplake, Sonning, Sonning Common, Theale, Tilehurst,
Twyford, Warfield, Wargrave, Winnersh, Wokingham, Woodcote, Woodley and Yateley


 Rev : 28th November 2007 © Michael Roberts 2006