Glossary of
General Building Terms & Surveying Jargon

Whilst surveyors endeavor to avoid jargon in their reports, the use of some technical terms is unavoidable. To bring some light into these, we have put together some common building terms & building surveying jargon.

Abutment – an intersection, usually between a roof and a wall.

Access Tower – a portable scaffold that allows quick and cheap access to high areas.

Aggregate – broken stone, gravel or sand used with cement to form concrete. Aggregates may be coarse or fine and are often used in the construction of “soakaways”.

Airbrick – a perforated brick, terracotta or plastic vent built into a wall for providing ventilation. Often used to ventilate the underside of timber ground floors, fireplaces or a roof space.

Apron – a metal strip, usually lead or zinc, used as a seal. Often fitted to chimney stacks and tile hanging. Also a section of wall below a window.

Apotropaic Markings – Apotropaic, ritual or ‘witches’ marks were carved into doors, windows and fireplaces where air, and therefore witches, could enter a building to protect them from such evil spirits. Although common on doors and jambs of doorways, they are most likely to be found around fireplaces. The most common markings are interlocking circles (some carved to create a six-petalled daisy flower effect), concentric circles and intersecting lines creating crosses and M’s representing the Virgin Mary or double V’s for ‘Virgin of Virgins’.

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.

Asbestos – material used in the past for insulation and fire protection. Can sometimes be a health hazard and specialist advice may be needed if asbestos is suspected or found. Typical locations in houses are roofs, soffit boards, textured (Artex type) ceiling and wall finishes, rainwater fittings and older plastic tiles etc.

Asbestos Cement – cement mixed with up to 15% asbestos fibre as reinforcement. Fragile -will not usually bear heavy weights. Hazardous fibres may be released if cut or drilled. The material is usually safe if left in-situ. If disposal is required the waste should be taken to an appropriate disposal site. At present, there is no requirement for this to be undertaken by a licensed asbestos removal contractor.

Ashlar – Finely dressed (finished) stone – usually in high quality construction.

Asphalt –  black, tar-like substance impervious to moisture. Used on flat roofs and floors.


Bakelite – an early plastic often used in old electrical fittings.

Ball Valve (Ballcock) –  valve operated by a ball floating in a cistern. Barge Board – a sloping board built along a gable edge of a roof. Balanced (or room sealed ) Flue – common flue type normally serving gas appliances, which allows air to be drawn to the appliance whilst also allowing fumes to escape.

Baluster –   a post or vertical pillar supporting a handrail or parapet rail.

Balustrade –  a collective name for a row of balusters or other infilling below a handrail on a stair or parapet.

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 construction. Often timber in older buildings.

Beetle Infestation – larvae of various species of beetle, which tunnel, into timber causing damage (often called woodworm). Specialist treatment normally required. Can also affect furniture.

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 cross timber laid over ceiling joists to reduce their effective span and prevent sagging.

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.

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 being English, Flemish, header, stretcher, rat-trap, diagonal or garden wall bond.

Bonding Timbers – timbers built into the walls in older houses to provide restraint. Unfortunately, these can easily rot and are often affected by wood-boring insect attack.

Bonnet tile – a hip tile with a bonnet-like appearance.

Box Gutter – square shaped gutter, often found behind a parapet wall.

Breeze Block –  originally made from clinker cinders (or “breeze”) -the term now commonly used to refer to various types of concrete building blocks.

Bressumer –  A lintel, often timber, over a shop front, fireplace or bay opening.

Building Paper –   Heavy-duty paper, usually incorporating a bitumen layer. Was often used as a lining under roof tiles in the 1960’s. Tears easily.

Butterfly Roof – ‘M’ shaped roof usually hidden at the front with a parapet wall. The hidden central valley gutters are often a source of nuisance.

Buttress – a wall, usually triangular in shape, built to restrain bulging. Temporary buttresses can be constructed in timber and are used during construction, typically if a facade is being retained and built behind.

Carriage – A substantial timber that runs along the underside of a staircase.


Cames –   The lead bars in leaded windows.


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 Window – a window composed of hinged, pivoted or fixed sashes.


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 and held together with metal ties that can rust. The wall cavity is now usually insulated.


Cavity Wall Insulation –  filling of wall cavities by one of various forms of insulation material: Beads –  polystyrene beads pumped into the cavities. Will easily fall out if the wall is broken open for any reason. Foam –  urea formaldehyde foam, mixed on site and then pumped into the cavities where it sets. Can lead to problems of dampness and make replacement of wall-ties more difficult. There have also been some health concerns. Fibreglass – usually built-in during construction. Mineral Wool – inert mineral fibre pumped into the cavity or built-in during construction.


Cavity Wall Tie – a twisted piece of metal or similar material bedded into the inner and outer leaves of cavity walls intended to strengthen the wall. Failure by corrosion can result in the wall becoming unstable. Replacement ties are then required.


Cesspool (cesspit) – a simple method of drainage comprising a holding tank, which needs frequent emptying. Not to be confused with a “septic tank” which treats waste.


Chipboard –  often referred to as “particle board”. Chips of wood compressed and glued into sheet form. Cheap method of decking to flat roofs, floors and (with Formica or melamine surface) used extensively for furniture, especially kitchen units.


Cill – see “sill”.


Cleaning Eye – sometimes known as an ‘access eye’ or ‘rodding eye’. An opening in a drain or ventilation pipe, covered by a plate, the removal of which allows the drain to be rodded to clear blockages.


Cladding – the non-loadbearing external skin of a wall or roof used to keep the weather out.


Cob –   walling of damp earth sometimes mixed with cement, rammed without reinforcement into a formwork. This old method of walling is known in Oxfordshire and Buckinghamshire as Wychert.


Cold Roof – a roof in which the insulation is placed below the deck or structure. Collar Beam –  horizontal tie beam of a roof, which is joined to opposing rafters at a level above that of the wall plates.


Collar –   horizontal timber member designed to restrain opposing roof slopes. Absence, removal or weakening can lead to roof spread.


Combed wheat Reed – the most common method of thatching in our area. Straw is used, rather than water reed as the name suggests.


Combination Boiler –   central heating boiler that also provides hot water on demand, sometimes within a pressurised system. With this form of boiler there is no need for water storage tanks, hot water cylinders etc.


Condensation – a type of dampness caused by relatively warm and moist air meeting a colder surface. The ability of the air to hold water decreases as it gets colder and the excess water condenses onto the surface. Often occurs to windows and the lower areas of walls. Condensed water is very clean and is often associated with the growth of black mould. Easily confused with rising damp.


Conduit – usually a metal or plastic tube used to protect electrical cables.


Consumer Unit (distribution board) – fuses or circuit breakers providing short circuit protection to an electrical 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, brick, timber or metal jutting out from a wall to support a weight above.


Cornice –   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, slates etc. including any mortar laid with them.


Cover Flashing – vertical flashing overlapping the vertical upturned parts of a roof covering or other flashing.


Coving –  curved junction between wall and ceiling.


Cowl – a cover often fitted to an unused chimney flue to prevent rain penetration and also provide some ventilation.


Crazing – hairline cracks on the surface of concrete, render or plaster usually of random pattern over a large area. Usually indicates failure.


Crown – the top of an archway.


Cruck Beams –  pairs of curved timbers, which run from ground level and meet at the ridge.


Cut Valley – a gutter at the junction of two roof where the slates or tiles are cut to meet on the valley line.


Dado Rail –   a moulding fixed to the wall or capping panelling and forming the top most part of a dado. Originally designed to avoid damage to the wall where people or furniture brushed against it.


Damp-Proof Course (or DPC) –  layer of impervious material (mineral felt, PVC etc) incorporated into a wall and designed to prevent dampness rising up the wall or lateral dampness around windows, doors etc. Various proprietary 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.


Distemper – old form of painted decoration made from chalk and animal glue.


Dormer – a window built out from a roof slope.


Dormer Cheek – the vertical side of a dormer window.


Downpipe – vertical pipe which brings rainwater to ground level from roof gutters or waste water from hoppers.


Double Glazing – a method of thermal and sound insulation usually either with sealed units – two panes of glass fixed and hermetically sealed together; or secondary – a second “window” positioned inside the original window.


Double Hung – a window in which the opening lights slide vertically within a cased Sash Window frame, counter balanced by weights supported on sash cords that pass over pulleys in the frame.


Drip – groove under an overhanging edge (e.g. window cill) designed to stop water running down the face of the building.


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.

Need A Free Estimate?

Eaves – the overhanging lower edge of a roof.


Efflorescence –  powdery white salts crystallized on the surface of a wall as a result of moisture evaporation. Unsightly, but causes no damage.


Engineering Brick –   particularly strong and dense type of brick, often used as a damp proof course in older buildings.


English Bond – a traditional form of solid wall construction with brick courses (layers) laid with headers (the short end) laid alternately with stretchers (the long side).


Expansion Tank – small tank required for many central heating installations to provide water for the system and to allow for overflow.


Fall – a slope, typically to a ‘flat’ roof, designed to allow water to drain away.


Fanlight – a window above a door or casement.


Fascia – a board fixed to the rafter ends along the roof eaves – usually used to fit gutters.


Fibreboard –   lightweight board material of little strength, was used in ceilings, or as insulation to attics. Considered to be a fire risk and usually best removed. Some of the paper backings to fibreboard can contain asbestos.


Fillet – mortar used to seal a junction, usually between roofs and brickwork in older property. Lead flashings are now usually used.


Flagstones – large stones used as an attractive floor finish.


Flashing –   a seal, usually between a roof and wall or chimney. Normally constructed in metal, but can be felt or proprietary material. Cement flashings are usually called fillets.


Flaunching – 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.


Flat felt roof – common type of flat roof made from built up layers of felt. Fairly cheap, but often fails suddenly and needs regular re-covering.


Flemish Bond – a traditional form of solid wall construction with the bricks laid with headers (the short end) laid alternately with stretchers (the long side).


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


Flue Lining –  metal (usually stainless steel) tube within a flue. Essential for high output gas appliances such as boilers. May also be manufactured from clay and built into the flue. Other proprietary flue liners are also available.


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 Drain – a gravel filled drainage trench, typically constructed against a wall. Can be a cost effective way of reducing damp caused by high ground levels without the need for extensive removal of paths/hardstanding.


Frieze – The area of an internal wall above the picture rail.


Frog –   an indention, usually V shaped in the bedding face of the brick to reduce its weight. “Frog down ” or “Frog up” are the generally accepted ways of describing how the brick are laid.


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


Ground Heave – swelling of clay sub-soil due to the presence of moisture: can cause an upward movement of floors or foundations in extreme cases.


Gulley – 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.


Haunching – see “Benching”. Also term used to describe the support to a drain underground. Head – upper horizontal member of a door frame, window frame, partition frame etc.


Hip – the junction between the slopes at the angled end of a roof.


Hip Tile – a saddle shaped or angular tile fitting over the junction of the roof slopes at a hip.


Hopper – enlarged top usually to a vertical down pipe to receives water from rainwater or waste pipes.


In Situ – “In position” – applied to work done in the position where it is finally required, e.g. concrete may be pre-cast in sections which are later taken to the position where they are required or it may be cast ‘in situ’.


Inspection Chamber – commonly called the “man-hole”: 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.


Interstitial Condensation – condensation which occurs within the thickness of a material, rather than on its surface.


Jamb – vertical side face of a doorway or window.


Joist – a timber or steel beam directly supporting a floor and sometimes alternatively or additionally supporting a ceiling. Steel beams are usually referred to as RSJs (rolled steel joists).


Kerb – profile fixed to a flat roof deck abutting an adjacent wall, but not fixed to it. Usually of shaped timber construction.


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


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


Lath – any base for plasterwork; typically thin wooden strips in older property. Now mainly expanded metal.


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.


Load-Bearing – usually applied to walls or other structures which carry loadings from walls, floors or roof at higher level.


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


Long Straw – method of thatching with straw. Only has a short life.


LPG – liquid Petroleum Gas or Propane. Available to serve gas appliances in areas without mains gas. Requires a correctly positioned storage tank or bottles. Can be relatively expensive.

Macerator – an electrical device attached to a WC that shreds and pumps away the waste. This enables the use of small diameter waste pipes and enables the fitting of a WC in locations away from soil pipes or in basements.

Mansard Roof – pitched roof which has, on each side, a shallower upper slope and a steeper lower slope.

Mortar – mixture of sand, cement, water and sometimes lime used to join stones, blocks or bricks.

Mortice Lock – lock set within the door thickness.

Mastic – a permanently flexible waterproofing material mostly used for sealing external or water-vulnerable joints in building or glazing etc.

Mullion – vertical bar dividing individual lights in a window.


Newel –  stout post supporting a staircase handrail at top and bottom. Also, the central pillar of a winding spiral staircase.


Open Valley – valley gutter in which the adjoining slates or tiles are so cut that the metal sheet or other waterproof material lining the valley, is exposed. Open valley gutters are less prone to blockages than cut valleys.

Oversite –   rough concrete below timber ground floors.


Padstone – Hard brick or concrete used to spread a point load on a wall – often below a beam.

Parapet – low wall along the edge of a roof, balcony etc.

Parapet Gutter –   a gutter usually provided with a flexible metal or other impervious lining. Used behind a parapet or sometimes at a valley. Frequently hidden and often a source of damp.

Partition – wall between rooms usually non-load bearing.

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.

Plywood – board made from veneers of wood glued with the grain laid at right angles.

Pointing – the outer edge of mortar joint between bricks, stones etc.

Powder Post Beetle – (Bostrychide or Lyctidae family of beetles). A relatively uncommon pest that can, if untreated, cause widespread damage to structural timbers.

Purlin – horizontal beam in a roof upon which rafters rest.


Quoin – the external angle of a building; or specifically, bricks or stone blocks forming that angle.


Radon Gas – colourless and odourless gas prevalent in some areas. Linked to cancer.

Rafter –  a sloping roof beam, usually timber, forming the carcass of a roof.

Random Rubble – basic early method of stone wall construction with no attempt at bonding or coursing.

Rendering – cement or lime covering of a wall either internally or externally, sometimes with pebbledash, stucco or Tyrolean textured finish.

Reveals – the side faces of a window or door opening.

Ridge –  the highest part or apex of a roof.

Ridge Tile – a specially shaped tile for covering and making weather-tight the ridge of a roof. These tiles may have a rounded or angular cross-section.

Riser – the vertical part of a step or stair.

Rising Damp –   moisture soaking up a wall from below ground, by capillary action which can cause rot in timbers, plaster decay, decoration failure etc.

Roof Deck – usually timber or ply boarding to a flat roof below the waterproof layer.

Roof Spread – outward bowing of a wall caused by the thrust of a badly restrained roof framework (see (collar”).

Roof Void – unused space between the roof and the ceiling of the highest storey (often called the loft or attic).

RSJ – frequently used abbreviation for a Rolled Steel Joist.


Sarking Felt – felt or other lining laid across rafters of a pitched roof to provide a secondary means of defence against water penetration.

Screed – final, smooth finish of a solid floor; usually cement, concrete or asphalt.

Scrim – coarse mesh used for bridging the joint between plasterboard sheets to prevent cracking. Used to be cotton or canvas, now mainly plastic.

Secondary Glazing – additional layer of glazing fixed in its own frame within a window opening. Often preferred in older or listed buildings where it is important to preserve the existing frames.

Septic Tank –  private drain installation whereby sewage decomposes through the action of bacteria, which can be slowed down or stopped altogether by the over use of chemicals such as bleach, biological washing powders etc.

Settlement – downward movement of a structure due to its own weight rather than due to another factor, such as a tree or defective drain etc. 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.

Shakes – naturally occurring cracks in timber; in building timbers, shakes can appear quite dramatic, but strength is not always impaired.

Shiplap –   horizontal external boarding, usually timber or PVC-u.

Shingles – small rectangular slabs of wood used on roofs instead of tiles, slates etc. Sometimes also used to face walls.

Skylight – a window set into a roof.

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. Stepped flashings are used over the soakers at a joint against a wall.

Soffit – the underside of an arch, beam, staircase, eaves or other feature of a building.

Soil Pipe/Soil Stack – a vertical pipe conveys sewage to the drains. Its upper end it usually vented above the eaves.

Solid Fuel – heating fuel, normally wood, coal or one of a variety of proprietary fuels.

Soldier Arch – flat arch of uncut bricks on end, usually over a window opening.

Sole Plate – the first part of any timber framed building to be installed

Spall – splitting of masonry, tiles etc. Usually due to the freezing and expansion of trapped water (frost damage).

Spandrel – panelling above and to the sides of an arch; also the space below a staircase.

Spindle – a balluster. Often a decorative series of timbers infilling between the bannister and stairs.

Stopcock – a valve on a gas or water supply pipe which is used to cut off the supply.

String – the sides of a staircase. The one fixed to the wall is the ‘wall string’; the other is the ‘outer string’.

Stud Partition – lightweight, sometimes non-load bearing wall construction, comprising a framework of timber faced with plaster, plasterboard or other finish.

Strut –   a support, usually a roof timber.

Subsidence –    ground movement, generally downward, due to failure or shrinkage of the subsoil. Often caused by trees, drains etc.

Sub-Soil – soil lying immediately below the topsoil.

Sulphate Attack – chemical reaction, activated by water, between tricalcium aluminate and soluble sulphates which can cause deterioration in brick walls and concrete floors.

Surface Water – another term for rainwater.


Tell-tale – a measure fixed across a crack to monitor movement. Strips of glass used to be fitted to check for movement and can occasionally be seen on older buildings.

Tie Bar – metal bar passing through a wall, or walls, bracing the structure. often used to correct bulging walls.

Torching – traditional method of waterproofing by applying mortar to the underside of roof tiles or slates. Rarely effective, and now not used as modern roofs are usually lined.

Transom – horizontal bar of wood or stone across a window or top of door.

Trap – a ‘U’ shaped bend in a waste pipe, soil pipe or gulley containing enough water to provide a seal and prevent the ingress of foul air into a building.

Tread – horizontal part of a step or stair.

Trussed Rafters –  (or pre-formed trusses) method of roof construction utilising prefabricated triangular framework of timbers. Now widely used in domestic construction.


Underpinning –    method of strengthening weak foundations whereby a new, stronger foundation is placed beneath the original. Underpinned properties can be difficult to sell and insure.


Valley Gutter –   horizontal or sloping gutter, usually lead-or-tile-lined, at the internal intersection between two roof slopes.

Verge – the edge of a sloping roof which overhangs the gable. Verges are often finished with mortar and a barge board below.

Ventilation – necessary in all buildings to disperse moisture resulting from bathing, cooking, breathing etc, and to assist in prevention of condensation. Particularly important with timber ground floors to reduce the rate of decay to the timbers.


Wall Plate – horizontal timber in or at the top of a wall supporting floor joists, ceiling joists or rafters.

Warm Roof – a roof where the insulation is placed between the roof deck or structure and the covering.

Waste Pipe – a pipe usually carrying water away from a basin, bath or sink.

Water Bar – small metal bar rising above the level of threshold to a door to prevent water blowing below it.

Water Reed – very durable thatching material. Used to be sourced principally in Norfolk and is often called Norfolk reed.

Weather Strip – moulding fitted at the base of an external door to throw water clear from the threshold below.

Written by Andrei H.
29th Feb 2021 (Last updated on 6th Apr 2021)
10 minute read
AndreiH Profile Pict
Scroll to Top