Common building terms

Unless you have many years experience of working on houses you may not know what the technical terms for things in, or even on, your home are. Within the building or construction industry you will be find many unusual terms and many terms that you’ve known for other things for years and never realised that they refer to something construction related too. We’ve created this handy A-Z guide to help you look like you know what you’re talking about when you are looking for particular services or products.

Airbrick – A perforated brick built into a wall for providing ventilation.

Arch – A curved structure built to distribute weight evenly over a wall opening.

Architrave – A moulding around a doorway or window opening. Often covering the joints between the frame and the wall finish.

Arris – The sharp external edge where two surfaces meet at a point.

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 and commonly found on terraced houses.

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, allowing air to be drawn to the appliance from outside and 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, often used to support roof tiles or slates.

Bellcast – Thickening out of render 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.

Binder – A length of wood used to provide cross bracing to a set of roof trusses. This term can also be used to describe 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 enabling the units to be joined together. There are different types of bond used in domestic construction, the principal types used 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 beam, 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 over a wall, parapet or chimney, usually using tiles or stone or concrete copings

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.

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.

Chipboard – Often referred to as “particleboard”. Chips of wood compressed and glued into sheet form. Often used as a cheap method of decking flat roofs, floors and some 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.

Combination Boiler – A central heating boiler that also provides hot water “instantaneously“ on demand, usually within a pressurised system.

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, plaster, 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 – A course of tiles projecting from 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 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 incorporated into floors or slabs.

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

Dry Rot – 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 – The side wall of a house or building.

Flashing – A sheet cover formed over a joint, such as between a roof covering and a chimney or wall, to render it waterproof.

Flaunching – A mortar weathering on the top of a chimney stack surrounding the base of the chimney pots to throw off the rain.

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 – Often used to describe the handles, knobs, locks etc. fitted to doors and windows when in a building context.

Gable – The upper section of a wall, usually triangular in shape, at the end of a ridged roof.

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.

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 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 – An access point to a drain, usually a chamber with the drainage channel at its base and a removable cover at ground level. Commonly referred to as a manhole.

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.

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.

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.

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 used to describe 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 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 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.

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.

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) – shortened, common term for 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.

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.

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 – A downward movement resulting from failure of the components of the building, normally the foundations. All properties ‘settle’ to some extent and this shows through cracks and distortion in the walls.

Sewer – A large, underground pipe or drain used for conveying waste water and sewage.

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 used on roofs instead of tiles, slates etc. and sometimes 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, which takes 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.

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. Used 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 – 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 wate.

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