Last Updated on January 3, 2024

If your property is undergoing a building survey, you may be wondering about certain terms used by your surveyor or in the building survey report itself. This industry is highly jargonistic, with unique terms that you may not come across in everyday life, which can sometimes make things difficult to understand. However, a good building surveyor will be able to answer any questions you may have regarding your survey, including providing definitions of certain terms. 

Just in case you need to refer back to those definitions throughout your survey and beyond, you can use our glossary of building surveying terms below.

Aggregate - Pebbles, shingle, gravel etc. used in the manufacture of plaster, mortar, concrete, and in the construction of "soak ways".

Aggregate – Pebbles, shingle, gravel etc. used in the manufacture of plaster, mortar, concrete, and in the construction of “soak ways”.

Air Brick – Perforated brick or grating set into wall to provide ventilation. These are most frequently used at the base of walls to ventilate areas beneath joists and boarded ground floors but can sometimes be found in walls and roof spaces where they provide general ventilation.

Architrave Joinery – moulding around window or doorway.

Asbestos – Fibrous mineral used in the past for insulation. Can be a health hazard. Specialist advice should be sought if asbestos (especially blue asbestos) is found. Can be found in building construction up to 2000.

Asbestos Cement – Cement with 10-15% asbestos fibre as reinforcement. Fragile and will not bear heavy weights. Hazardous fibres may be released if cut or drilled.

Ashlar – Finely dressed natural stone: the best grade of masonry. In some render finishes the surface is incised/scored to give the impression of ashlar work.

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

Back Addition – The rear, narrower, part of a terraced or semi-detached building that is contemporary with the main building.

Balanced Flue – Common metal device 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 (often turned, carved or ornamental) that supports a handrail or parapet rail.

Weathered outdoor balustrade

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

Board, Barge Board, Gable Board – Stiff member lining on roof at gable or hip. Wide board – on older work often carved – fitted below tiles of overhanging verge (see below) to gable

(see below).

Beam – A long timber or steel member of a large section used in tension (tie beam) or in compression (floor beam) to provide support to other elements in a structure. A Cambered Beam is a slightly curved or angled beam, the centre being higher than the ends; generally used as tie beams or collar beams.

Beetle Infestation – (Wood boring insects) Larvae of various species of beetle which tunnel into timber causing damage. Specialist treatment normally required. Can also affect furniture; indeed, some infestations originate in antique furniture and are then brought into a house.

Benching – Smoothly contoured concrete slope beside drainage channel within an inspection chamber. Also known as Haunching.

Bitumen – Black, sticky substance related to asphalt. Used in sealants, mineral felts and damp-proof courses.

Bond – The regular arrangement of bricks or stones in a wall that join together to form a wall. Different forms of bond have specific names and include English, Garden, Flemish, Header, Stretcher.

Bonds - timber diagonal strengthening frames

Brace – A diagonal timber strengthening a frame.

Breeze Block – Originally made from cinders (“breeze”) the term now commonly used to

refer to various types of concrete and cement building blocks.

Bressumer – A beam, usually timber, spanning an opening and supporting a wall above,

e.g., over fireplaces, bays, etc. In timber framing it is usually the sill of the upper wall above a jetty.

Bridging Beam – Large section timber (underside sometimes carved and lower edges

usually chamfered) inserted parallel and (usually) mid-way between two walls to provide support to floor joists where the joists are not long enough to span between the walls, or the span is such that very deep joists would be required.

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.

Recarbonation is the natural process whereby lime mortar absorbs carbon dioxide from the atmosphere and slowly hardens. If lime mortar is allowed to dry too quickly or dries too slowly the rate and degree of carbonation is affected detrimentally and failure of the lime mortar/render can occur.

Carpenter’s Marks – Marks inscribed on the face of a timber frame member to show the erection sequence.

Carriage Beam – An inclined timber or steel parallel to the two strings underneath a flight of stairs to provide mid-span support to the treads.

Cavity Wall – A wall usually external, comprising inner and outer ‘skin’/’leaf’, each either brick, block, or brick (outer) and block (inner). Space between skins of about 50mm (2″). Skins linked by wall ties which should be kept clean of mortar droppings during construction, otherwise ‘bridging’ can occur, leading to dampness internally. Properly constructed, cavity walls are more resistant to damp penetration than solid walls. Thermal insulation is also higher. In modern timber framed dwellings, timber framing forms the inner ‘skin’, often clothed with an outer skin of brick or rendered block, thus forming a ‘cavity’.

Cavity Wall Insulation – In recent years cavity filling with insulation materials has come into use to preserve warmth in buildings. Not always suitable for exposed positions because if the insulation becomes wet its value is low and problems of damp and condensation can occur. Unless properly done can form a ‘bridge’ between skins of wall across which moisture could pass. Various forms of insulation material include: – Beads: Polystyrene beads pumped

into the cavities. Will easily fall out if the wall is broken open for any reason. – Foam: Urea formaldehyde form, mixed on site, and pumped into the cavities where it sets. Can lead to problems of dampness and make replacement of wall-ties more difficult. Some doubts have also been expressed on the possibility of toxic fumes emanating from some foam insulation. There is no evidence that this is a significant problem in this country. – Rockwool: Inert mineral fibre pumped into the cavity. It is important that the work is done by an experienced and reliable company.

Cesspool/Cesspit/Holding Tank – A simple method of drain; a watertight chamber in which sewage effluent is collected. Has to be emptied at regular intervals – service usually provided by Local Authority for which a charge is made. It can be a substantial annual outgoing if frequent emptying is needed. Sometimes an outlet is provided from the cesspool to allow some soakage into surrounding ground – not strictly in accord with Local Authority regulations but most ‘turn a blind eye’. Should be regarded as a simple holding tank that needs frequent emptying. Not to be confused with Septic Tank.

Chamfer – An angled (sometimes carved) surface where the edge of a timber has been cut away along its length.

Cheeks – The side ‘walls’ of dormer windows.

Chipboard – Also 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) furniture, especially kitchen units.

Collar (in roof) – Timber that ties across between rafters on either side of a roof at some point above the feet of the rafters, like a cross beam only smaller. It is a horizontal timber member intended to restrain opposing roof slopes; absence, removal or weakening can lead to Roof Spread.

Collar (in drain) – Wider end of pipe into which another pipe fits.

Combination Boiler – Modern form of gas boiler which activates on demand. With this form of boiler there is no need for water storage tanks, hot water cylinders etc. and generally the pressure is much better for showers.

Common Furniture Beetle – See Woodworm.

Condensation – Occurs when warm moist air meets a cold surface. The water in the air

then either settles as water droplets on the surface (as it does on windows for example) or, if the surface is absorbent, it soaks into the surface. In the latter case condensation is often not noticed unless or until mould appears. (See also Ventilation)

Condensing Boiler – A modern boiler whereby condensing water vapour in the exhaust gases are recovered as the latent heat of vaporisation, which would otherwise have been wasted.

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

Cornice – A decorative ornamental projection (usually of plaster or carved timber)

often seen in the angle between a wall and ceiling, or under a jetty or any

other projection internally or externally.

Cove/Coving – Similar to a cornice but a concave surface, usually of plaster and usually

plain. Curved junction between wall and ceiling or (rarely) between ceiling and floor.

Cross Beam – See ‘Tie Beam’.

Cross Wing – Secondary element of a house built at 90º to the main axis on plan.

Dado Rail – Wooden moulding fixed horizontally to a wall, approximately 1 metre above the floor, originally intended to protect the wall against damage by chair-backs, but now very much a decorative feature.

Damp Proof Course [DPC] – Layer of impervious material to prevent passage of water either horizontal (inserted at base of walls to stop rising damp) or vertical (e.g. where room is below ground level to prevent lateral passage of water from ground into wall). Most common material used today is heavy-duty polythene and some has a lead core. In older works, slate was often used (two courses set in cement mortar) and for much of the 20th century bituminous felt was used. A rarer form, cheaper and ineffective in the long term, was just a layer of bitumen.

When inserting a new DPC in an old building a ‘chemical’ form is frequently used consisting of impregnating wall at ground floor level with chemical, which percolates walls and forms a barrier against rising damp. Other forms of retrospective DPC include ‘electro osmosis’ and use of ceramic tubes (often circular, but also triangular and rectangular).

Damp Proof Membrane [DPM] – Similar to DPC but in solid ground floor to prevent damp through the floor. Should be connected to DPC in surrounding walls to form damp proofing

continuity and be fully effective.

Death-watch Beetle (Xestobium Refovillosum) – Serious insect pest in structural timbers, usually affects old hardwoods with fungal decay already present.

Dormer – A window formed in a roof slope or at eaves where it cuts into the lower edge of the roof (an ‘eyebrow’ dormer).

Double Glazing – A method of thermal insulation usually a sealed unit formed by two panes of glass fixed and hermetically sealed together.

Downpipes – Drainage pipes from guttering.

Dragon Beam – In a building that has a jetty on two adjacent sides, this is the floor beam set

diagonally in the angle between the two into which the floor joists are tenoned. It is supported at the corner by a dragon post.

Dry Rot (Serpula Lacrymans) – This is but one of the ‘brown rot’ family of fungi, which are fungus growths that cause breakdown in fibrous texture of timber. Before any action is taken, it is necessary to establish whether the rot found is live and active or whether it is historic. If the latter, no action may be necessary. Can flourish in moist, unventilated areas. Not to be confused with wet rot (‘white rot’ family).

Eaves – Projecting/overhanging edge of a roof.

Efflorescence – Salts crystallised on the surface of a wall as a result of moisture evaporation.

Engineering Brick – Particularly strong and dense type of brick, sometimes used as a damp-proof course.

Fascia – Visible vertical board trimming rafters or any other projecting timber ends. When used to support a gutter it is more usually called a gutter board.

Fibreboard – Cheap, lightweight board material of little strength, used in ceilings or as insulation to attics.

Fillet – An infill material in the angle between two surfaces, usually triangular in section, which provides a finish to a corner and often forms the ‘weathering’ surface when used externally. Sometimes it has pieces of tile or slate set into it.

Flashing – Method of weatherproofing the joint between roof covering and brickwork by

lead (in good quality work) or other metal, but can also be cement, felt or proprietary material (then usually called a fillet – see above).

Flaunching – Contoured cement around the base of chimney pots, to secure the pot and to throw off rain.

Flue – A 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.

Folding Wedges – Two wedge shaped pieces, usually timber, that are inserted into a gap from opposite sides and tighten against each other as they are pushed into the gap.

Foundations – Normally concrete, laid underground as a structural base to a wall – in older buildings these may be brick or stone.

Frog – A depression imprinted in the upper surface of a brick, to save clay, reduce weight and increase the strength of the wall. Bricks should always be laid frog uppermost.

Fused Spur – Power socket that does not have a plug going into it, but instead the cable from an appliance like a fridge, radiator, burglar alarm etc., and has a fuse socket built into it.

Gable – Usually triangular upper part of an external wall, at an end or either end of a ridged roof.

Gang – Referred to for 13amp power points. 1 gang = 1 single socket; 2 gang = 1 double socket.

Garderobe – Medieval name for a toilet.

Girding Beam – Also known as a girth, rail, or storey beam. A horizontal beam in a wall or cross frame at the level of the upper floor, or roughly half-way between sill and wall plate. Running the full length of a bay or width of a building – may be divided in two by an intermediate post.

Gully – An opening into a drain, normally at ground level, placed to receive water etc. from downpipes and waste pipes.

Gutters – Formed in cast iron in older properties and of two basic designs (i) half round – semi-circular section, fixed to fascia with brackets. (ii) Ogee – a different pattern with vertical rear side screwed direct to fascia – disadvantage is that it restricts decoration in fascia and rear face of gutter; rusting and failure of gutter can result, and in extreme cases, rot in fascia

and feet of rafters.

In more recent times, vinyl (plastic) guttering and downpipes are commonly used and have the advantage of not requiring painting, but can fade and/or become brittle. There are also extruded metal goods (usually aluminium).

Hall (historic) – Family accommodation in a medieval house.

Hanger – Vertical timber fixed between rafters and runner (see below) to provide additional support to ceilings.

Haunching – See Benching. It is also a term used to describe the support to a drain underground.

Header (masonry) – The short end face of a brick or stone.

Header/Feed/Expansion Tank – Small storage tank linked with the central heating and/or hot water system to top up water in that system independent of the main cold-water storage tank. It also allows for hot water in the system to expand safely into the tank. Such tanks are found with unpressurised systems.

Heave/Ground Heave – Upward movement of subsoil. This occurs where the subsoil is vulnerable to volumetric change and is often found where trees are removed, and the subsoil takes up water that had previously been removed by tree roots. Swelling of clay sub-soil due to absorption of moisture: can cause an upward movement in foundations and therefore cracking in walls.

Hip – External junction between two intersecting roofs – formed by roof slopes backwards from eaves instead of ending in a gable. Usually protected by tiles (hip tiles) even on a slate roof. Sometimes lead hip coverings are seen on slate roofs.

Inspection Chamber – Commonly called a manhole. 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.

Jamb – The vertical flank of a wall opening (door or window), usually to the full thickness of the wall.

Joists – Small section timbers that carry floor loads – usually laid flat in houses prior to c.1650. Horizontal structural timber used in flat roof, ceiling and floor construction. Occasionally also metal.

Jowl – The enlarged head of a main post, which permits the tie beam, wall plate, and post to be jointed together. The jowl can sometimes be a planted timber securing the joint and the term also applies to any enlarged head of any post.

Land – Drain Method of disposal of water beneath ground. Usually comprises a drain laid with open joints and surrounded by shingle or similar material through which water can disperse into surrounding soil.

Landslip – Downhill movement of unstable earth, clay, rock etc. often following prolonged heavy rain or coastal erosion, but sometimes due entirely to sub-soil having little cohesive integrity.

Lath – Thin strip of wood used in the fixing of roof tiles or slates, or as a backing to plaster. Lath and plaster walls were very common in houses from the late 1800s to 1950s. Metal lath, ‘expanded metal lath’ (EML), is a form of lath that has been used since about the turn of the 20th century.

Lath and Plaster – Traditional way of forming plaster surface in ceilings or timber partitions.

Comprises a number of horizontal battens or laths, which form a key for the plaster. Now usually replaced by plasterboard.

Lintel – Beam normally of concrete or metal – sometimes timber – spanning opening in a wall to support the wall above. Horizontal structural beam of timber, stone, steel or concrete placed over window or door openings. LPG Liquid Petroleum Gas or Propane. Available to serve gas appliances in areas without mains gas. Requires a storage tank.

Manhole – See Inspection Chamber.

Mini Treatment Plant – Sometimes called by the trade name ‘Biodisc’. This is a small sewerage treatment plant for domestic properties. The plant discharges what is often considered to be ‘treated’ water and is therefore suitable for most private domestic drainage systems. It requires an electrical supply and needs annual checking, clearing and maintenance.

Mortar – Mixture of sand/aggregate, cement and/or lime and water, used to join stones or bricks.

Mouldings – Decorative profiles cut into the surface of a timber Mullions Vertical bar dividing individual lights in a window. Historically these were often shaped – diamond and/or ovolo.

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

Oversite – Rough concrete below timber ground floors: the level of the oversite should be above external ground level.

Parapet – Low wall along the edge of a flat roof, balcony etc. Also used for top of wall projecting above a roof at a gable end or eaves (when there would be a parapet gutter behind it).

Parapet Gutter – The junction between the roof and rear face of a parapet wall. Usually

lined with metal and running to an outlet to dispose of rainwater.

Pargeting – External plaster applied to a timber frame, the term usually refers to a carved or decorative finish.

Passing Brace, Passing Shore – A brace which passes across the other vertical or horizontal members in a frame, usually halved or lapped across and pegged to them.

Patress/Patrice Plate – The plate at the end of a Tie Bar. Often circular, but sometimes shaped (e.g. S) and sometimes forming letters or numbers.

Pier – A vertical column of brickwork or other material, used to strengthen the wall or to support a weight.

Plasterboard – Stiff “sandwich” of plaster between coarse paper. Now in widespread use for ceilings and walls, as well as being used for dry lining.

Plate – A horizontal timber at the head or foot of a frame, e.g., wall or sole plate (foot), sill plate (head). Also, a horizontal timber (usually laid flat) within or at the head of a masonry wall to take and spread loads imposed by floor or roof structures.

Plinth – A masonry structure on which a further structure or element sits. This is usually a wall below and supporting a timber frame.

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

Posts – In wall frames, the vertical members that rise to full height of the frame, being main posts at bay divisions or intermediate posts within the bay. In roof trusses, King Posts, Queen Posts, and Crown Posts carry longitudinal beams.

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

Psocids (common name – booklice) – A common but generally harmless pest. Nonetheless in numbers they can pose problems. Although known as booklice they like damp habitats. In

buildings, they are known to infest areas with new (damp) plaster, condensation affected areas, where there are leaks, etc. They are known to have caused infestations where damp thatch has created an appropriate habitat for them.

Principal Rafter – Larger section timbers jointed into the ends of tie beams and often forming part of a roof truss.

Purlins – Longitudinal horizontal roof members on which the rafters rest, intermediate between wall plate and ridge, carried by roof trusses and/or struts and giving support to the common rafters.

Quoin – The external angle of a building; or, specifically, bricks or stone blocks forming that angle. Usually a specific and sometimes projecting feature.

Rafter, Common Rafter – Small section inclined timbers (sometimes metal beams) installed parallel to one another forming the carcass of a roof to which the tiling battens or boarding for sloping roofs are fixed and carrying the roof covering. For a pitched roof, they run from wall plate to apex.

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

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

Rail – Short horizontal timbers in a timber-framed wall, other than a girding beam. Sometimes rail and cross rail are terms used for girding beams.

Reveal – Vertical side face of an opening for a window or doorway between the frame and outer face of wall.

Ridge – The apex of a roof. Usually with a horizontal timber at the roof apex,

supporting the top ends of rafters. Sometimes the rafters join with scissor

joints and no ridge timber. The ridge usually has tile covering (ridge tile).

Riser – The vertical part of a step or stair.

Rising Damp – A term often used/misused for moisture at the bases of walls and usually

said to be soaking up a wall from below ground, by capillary action.

Roof Spread – Outward bowing of a wall caused by the thrust of a badly restrained roof carcass (see Collar).

Roof Truss – Triangular framework of structural members supporting a roof, carrying

horizontal members (purlins) which in turn support common rafters. (See also ‘Trussed Rafter‘ below).

Runner or Binder – Horizontal timber placed at right angles to and above ceiling joists to stiffen ceiling and provide additional support.

Scantling – The dimensions of a timber. Traditionally, “scantlings” were small timbers such as rafters.

Scarf Joints – A timber joint able to support itself or take support without additional stiffening.

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

Secondary Glazing – In effect a second “window” placed inside the original window.

Septic Tank – Sewage disposal system normally comprising two or three linked chambers within which self-purifying (bacterial) process takes place. Beyond the tank is an outfall to drains (land) or a soakaway (see below) for the purified liquid effluent. The bacteriological action can be slowed down or stopped altogether by the use of chemicals such as bleach biological washing powders etc. Not to be confused with Cesspool/Cesspit.

Settlement – General disturbance in a structure showing as distortion in walls etc., possibly a result of major structural failure, very dry weather conditions, initial drying out of building materials, redistribution of loads when alterations take place, etc. Often of little current significance. (See also Subsidence)

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

Shingles – Small rectangular slabs of wood used on roofs instead of tiles, slates etc.

Sill – The lowest horizontal member of a window frame. A sill beam is the lowest member of a timber frame.

Soakaway – Method of water disposal, usually for surface water, i.e. hole dug in the ground and then filled with brick, rubble, or similar material and covered over. Disperses water from drains leading into it provided surrounding soil conditions are suitable.

Soaker – A metal detail at roof to wall and chimney junctions, usually under mortar fillets or flashings.

Soffit – The underside of an overhanging beam, eaves, balcony, or archway. Sometimes used as a term for a sloping section of ceiling underneath a roof, or the underside of a flight of stairs.

Solar – Private living accommodation in a medieval house.

Solid Fuel – Heating fuel, normally coal, coke or one of a variety of proprietary fuels.

Sole Plate/Sill beam – See Plate. The bottom horizontal member of a timber frame.

Spandrel – The triangular space between a brace and the post and beam to which it is

jointed. Space above and to the sides of an arch; also, the space below a staircase.

Stretcher (masonry) – The long face of brick or stone.

String, Stringer – A sloping board up each side of a flight of stairs to carry the ends of the treads and risers.

String-line, String-course – A decorative horizontal course of brick or stone along the wall of a building, often projecting slightly and usually in a contrasting material to the rest of

the wall.

Strut – Load bearing timbers normally supporting purlin (see above) and fixed at an angle down to a wall or some other load bearing point.

Stud Partition – Wall formed of pieces of timber (stud) covered plasterboard or lath and plaster in older work. Unless specially constructed, unlikely to give sound insulation of a solid (brick or block) partition. 

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

Studs – Vertical timbers in a wall or cross frame, which are not main or intermediate posts.

Subsidence – Ground movement, generally downward, possibly a result of mining activities or (more often) clay shrinkage.

Sub-soil – Soil lying immediately below the topsoil, upon which foundations usually bear.

Sulphate Attack – Chemical reaction activated by water, between tricalcium aluminate and

soluble sulphates. Can cause deterioration in brick walls and concrete floors.

Tie Bar – Metal bar inserted across (old) buildings to tie outer walls together, i.e. to arrest movement in structure and improve stability. Heavy metal bar passing through a wall, or walls, to brace a structure suffering from structural instability.

Tie Beam – Main timber horizontal beam dividing bays and giving cross support to a main frame.

Torching – Mortar applied on the underside of roof tiles or slates to help prevent moisture penetration. Not necessary when a roof is underdrawn with felt.

Transom – Horizontal member separating the lights in a window.

Tread – Horizontal part of a step or stair.

Trimmed Opening – An opening formed in a timber frame, the trimmer (or trim timber) receiving the frame member that would otherwise have run across and blocked the opening. Most often applied to openings trimmed in timber floors (for stairs) or in ceilings (for loft hatches).

Truss – A frame, usually of timber, made up of members joined together mainly forming triangles. Most often refers to a roof frame member that carries purlins and often incorporates a tie beam and collar.

Trussed Rafter – Derivative or roof truss (see above). Factory made timber framework used

instead of common rafters joined by metal connectors or adhesive. 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. 

The rebuilding of a structure below an upper part, but not necessarily as a result of structural movement or failure; e.g. the formation of a new plinth wall under a timber frame.

Valley – Internal angle formed by the outside surfaces of two adjoining roof slopes. Can be tiled or formed in lead or, less durably, in felt. May be called ‘valley gutter‘, particularly where horizontal, i.e. between two parallel adjacent sloping roofs.

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

Vapour Barrier – An impervious layer, usually polythene sheeting, used to prevent passage

of moisture into vulnerable parts of a structure, e.g. placed on the inner side of a timber framed wall, or below timber framing of a flat roof. To stop water vapour from living areas passing through from plasterboard into wall or roof cavity, where it could then condense and cause rot or other problems.

Ventilation – Necessary in all buildings to disperse moisture resulting from bathing, cooking, breathing etc. and to assist in prevention of condensation. Floors – necessary to avoid rot, especially Dry Rot; achieved by airbricks near to ground level. Roofs – necessary to disperse condensation within roof spaces; achieved either by airbricks in gables or ducts at the eaves. (see Condensation).

Verge – Edge of a roof which runs from eaves to ridge especially at a gable (usually cement pointed). This usually overhangs the gable. Where there are pantile roof coverings the verge is often covered with timber boxing.

Verge Board – Timber, sometimes decorative plastic material, placed at the verge of a roof: also known as bargeboard.

Wainscot – Wood panelling or boarding on the lower part of an internal wall.

Wall Plate – Horizontal timber at top of wall on which roof timbers, rafters or joists rest.

The horizontal member at the top of a timber frame wall.

Wall Tie – Metal (or plastic, or other) connector used to provide structural link between inner and outer skins of cavity wall.

Wastepipe – Drainage pipe for baths, basins, WCs.

Wattle and Daub – Infill between studs, the wattle being the timber rods (usually hazel sticks) and the daub being a mixture of clay/earth, chopped straw and lime putty.

Wet Rot (Coniophora Puteana) – Generic term for one of the ‘white rot’ family of fungi. Decay of timber due to damp conditions. Not to be confused with Dry Rot.

Wiffs – Brickwork walls dividing flues in a chimney.

Wind Brace – Brace running from principal rafter to purlin in a roof frame to stiffen the structure against wind pressure. In a wall frame, the brace runs from principal corner joints of a bay diagonally down to the girding beam and/or sole plate.

Woodworm – Colloquial term for beetle infestation usually intended to mean Common Furniture Beetle (Anobium Punctatum), which is by far the most frequently encountered insect attack in structural and joinery timbers. Eggs are laid by the insect and the resulting grub eats away within the timber for several years before emerging through distinctive and characteristic flight holes in spring/early summer. Serious infestation can ultimately result in breakdown of timber, but it is a relatively slow process. Other species are more voracious such as Death Watch Beetle and House Longhorn Beetle. The latter is particularly damaging in a short time.

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