Knowledge Base

The Knowledge Base is designed to help you understand the terminology used within home information pack documents, by people producing them and that you may come across during the sale or rental of properties.
 
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A B C D E F G H I J K L M N O P Q R S T U V W Y
Material used in smoothing and levelling painted and finished surfaces, eg glass paper, pumice stone, carborundum.
End support or pier designed to withstand the end thrust of an arch / a junction where building elements meet.
Chemical added during manufacture of gypsum plaster or production of concrete to speed setting and airing times.
See also Platform floor, Raised floor. A system that can deliver heating, ventilation, electrical power, voice and data cabling, and other utility services underneath an accessible, flexible modular floor.
Generally an access stair provided in offices or public buildings for the convenience of the occupiers but not designated a fire escape stair (under Part B of UK Building Regulations).
Hard, red Lancashire brick (UK) of high mushing strength.
Gas (C2H2) produced commercially, used in conjunction with oxygen to produce intense heat for welding metals. See also Oxy-acetylene plant.
The reduction of airborne or impact sound through a building by the application of discontinuous or dense construction.
The science of sound
A proprietary adjustable metal strut, sometimes referred to as a screw jack, used to provide temporary support to part of a construction or to other temporary works such as timbering or formwork.
Thermoplastic possessing excellent optical properties and good mechanical strength.
A material added to concrete or mortar as it is being mixed in order to modify its properties.
Loose particles of inorganic materials bound into a compact mass by cementitious material (concrete, plasters) eg gravel, hardcore, MOT type 1. See also All-in-one aggregate, Hardcore.
Issued by the British Board of Agrément, these certificates provide evidence of the suitability of materials, components, or processes for use in construction. See also British Standards.
Perforated building block inserted in general construction to allow air movement through walls and floor voids. Common sizes 102 × 65mm, 102 × 140mm.
A brick that allows air to pass through it. These bricks are built into the outer surface of a wall at a low level. The vents allow air to circulate in the area below a timber floor and help prevent the build up of damp moist air that ...
A system for regulating the humidity, ventilation and temperature in a building.
Minimum standards for test procedures on foul drainage systems.
Concrete containing air trapped in tiny bubbles which improves the resistance to frost damage. Mainly used in road construction.
See Acoustics.
Algae, lichens and mosses are commonly found growing on external surfaces of buildings, particularly where design features or maintenance faults result in frequent wetting of the surface. Sometimes their appearance in moderation may be ...
Aggregate containing a proportion of various sizes of material obtained from a pit, quarry or dredging operation.
A metallic material containing two or more metals, eg brass (copper and zinc), bronze (copper and zinc and tin). All non-ferrous (rust-resisting).
An unit of electrical current used for measuring its flow to an appliance, providing the necessary wattage.
Stout embossed paper used as a relief decoration on ceilings and walls. See also Paper hanging.
Metal tie built into masonry to prevent movement, eg coping stone fishtailed anchor, or to provide structural lateral support to roof wall plates, eg strap anchors. See also Ground anchor, Grounds.
In earthworks, a device or process for anchoring the end of rods or cables used for ground anchors.
See English Bond
A right to light flowing over adjoining land to existing windows: shall not be unreasonably obstructed.
Galvanised or stainless steel expended metal angle strips 50 × 1800mm to give a slight rounded reinforced edge to plastered corners.
Short piece of steel bolted or welded to the ends of secondary beam forming a connection between it and the primary beam (main beam). See Cleat.
Strip of wood, mortar or mastic asphalt of triangular section used for covering joints or internal angles.
The state of equilibrium in which granular materials remain stable without further sliding or collapse, eg wet sand 25º, rubble stone 45º. See also Friction.
Chemical name for quicklime. See also Lime.
Process of heating metals, alloys or glass, then allowing to cool slowly to increase malleability/ductility of metals and create less brittle glazing, eg toughened safety glass.
Application of a protective oxide coating on aluminium by electrolysis.
Air vent in a drainage system to prevent induced siphonage.
The highest point of a structure.
The point at which two slopes or angles meet, as with the top of a triangle. The highest point or peak.
The Building Regulation documents of England and Wales imposing requirements on design and building operations.
Provisional estimate of materials and labour in building operations.
A length of metal, usually lead, fixed into a groove (raggle) in masonry to cover and protect a joint with a roof. Also a board fitted below a windowsill.
Sheet lead or non-ferrous covering at the junction between a vertical surface and a pitched roof.
Horizontal boards forming a vertical face to a stairwell.
A domed, arched, semi-circular domed area or recess.
A number of arched openings resting on piers or columns giving access to a vaulted corridor.
Arrangement of separate units (bricks, stone blocks) supporting each other forming a curved structure bridging an opening.
High-quality or purpose-designed metal fittings, used throughout buildings, including door and window furniture.
Decorative trim fixed internally around doors and window openings masking the joint to conceal differential movement of materials and components.
Moulding round opening such as door or window
Sunken area around a building to allow light into a basement. Also the surface space of a building.
Material produced as a result of excavation.
Sharp edge where two plane surfaces meet, such as a corner of a joinery component or masonry.
Sharp external angle
A length of timber that is triangular in cross-section
Accurately dressed blocks of stone, built in courses with fine joints and flush surfaces.
The direction that a building faces, eg orientation of elevations or rooms (northerly aspect).
Bitumen mixed with mineral aggregates (limestone), eg asphalting – application of mastic asphalt for waterproofing.
Black, tar-like substance, designed to be impervious to moisture. Used on flat roofs and floors. Was used as a damp proof course in 1920s - 30s
Production or working drawings that detail the junctions between the elements and components of a building.
A sash bar for subdividing a window sash into smaller panes.
A skylit central court rising through several storeys with galleries and rooms off at each level.
A material or device used to interrupt and reduce sound levels.
A truss which forms the top storey of a dwelling but allows the area to be habitable by leaving it free of internal WEB members.
The limits of frequency of sound between 20 and 20,000 hertz, ie audibility testing of fire alarms.
A mechanical device similar to a rotary drill, used to bore large-diameter holes in the soil.
A fabric or metal covering to protect parts of a building primarily from the sun.
Structure of bricks roughly cut to form the voussoirs of an arch.
Three-dimensional (bird’s-eye view) of buildings, interiors and general layouts, the top view being a true plan with 45º × 45º or 30º × 60º projected lines.
A hinge that is surface fixed rather than edge fixed.
A flue used with a gas boiler that incorporates the air intake with the exhaust.
An aggregate that contains particles of several sizes.
Vertical rods, often moulded or decorated, forming the barrier at the side of a staircase.
Vertical post on a stair, which support the handrail
The combination of handrail and balusters protecting the side of a staircase.
A person assigned to work particularly with mechanical equipment, to ensure the safety of persons on or near the machinery, and to advise the machine operator of aspects of the work.
Wide board fitted on edge of tiles following the slope of the roof
A roof consisting of two or more curved shells in parallel.
In road construction, the under layer of the surfacing in flexible pavement construction.
The process that selects the proportions for the mix and mixes concrete.
The retained portion of a cut brick such as a half-batt, quarter-batt, etc.
A relatively small-section timber. Tile battens are the timbers to which roof tiles or slates are secured.
A narrow strip of wood.
Small timber members spanning over trusses to support tiles, slates etc.
Large-section timbers most frequently used for temporary works such as shoring.
Small convex moulding. Also used to describe a gun applied sealant
Having a small projecting moulding usually rounded in section (also cockbeaded).
Usually a timber member that assists in carrying a load. In shutters, bearers are used to support the sheet material in contact with the concrete.
A member designed to distribute loads over a number of trusses.
Bed
A layer of material forming a platform on which subsequent construction can be carried out.
A dovecote circular on plan and built in stone and shaped like a beehive. Usually built with horizontal projecting rings at intervals to guard against entry of vermin.
The slight flattening of the pitch of a roof at the eaves by the insertion of a short tapered piece of timber below the slates or tiles to give a graceful finish, like the rim of a bell.
A treatment at the base of a wall or window head where the render, roughcast or harling is brought out to form a drip, usually with a base of expanded metal.
In manhole or inspection chamber construction, benching is used to ensure that liquids are directed to the drainage channel.
Finely ground montmorillonite clay which, when mixed with water, forms a thixotropic slurry filling for excavation voids which exerts pressure. Often used in groundworks.
A bevel is when the ninety degree edge is planed to a shallower angle such as eighty degrees, producing a slope.
Tap fed by horizontal supply
A longitudinal member nailed to trusses to restrain and maintain correct spacing.
A notch in the underside of a RAFTER to allow a horizontal seating at the point of support (usually used with RAISED TIE TRUSSES).
A vee-shaped notch cut in a rafter in order to secure it to the wall plate.
A by-product of the oil industry widely used as a waterproofing compound and in bitumen macadam.
See Tarmacadam.
Mould spores are present in the fabric of all buildings but they are generally dormant and therefore completely harmless. Under the right (or wrong) conditions the mould spores will germinate resulting in extensive growths of unsightly ...
A thin layer of hoggin, gravel, or weak concrete used mainly under foundations or ground-floor construction in order to provide a clean and level working platform.
Sheet material made up of strips of hardwood or softwood, sandwiched between either a hardwood or softwood veneer. Comes in thicknesses of 25, 18 and 12.5mm
Short timbers fixed between chords to laterally restrain them
The square finishing course above a cornice or cope.
Masonry construction using preformed concrete or similar blocks.
Plaster that has lost its bond with the wall
A truss type formed by truncating a normal triangular truss.
A small timber moulding used to cover and decorate joins in timber construction such as doors and stairs.
Arrangement of bricks to ensure stability of brickwork. Examples are English, Flemish, Rat Trap. See Brickwork Bond
A T-shaped unit used in drainage to ensure that the drains are laid to the correct falls.
Cranked reinforced concrete lintel popular in the 1950s and 1960s.
A hole produced in the soil by an auger usually for construction of piles.
See CEILING TIE.
Rounded stone used with clay for wall building. (Scottish ‘bool’ for Bowl or boy’s marble.)
A rainwater gutter of rectangular cross section.
The diagonal member at the back of a framed-and-lined door to stiffen the framing and prevent sagging.
This can be Temporary or permanent members to provide additional stability.
A small sharp tipped device (similar to a small screwdriver) for boring small holes into wood, as a start or guide for screws
In sea defence works, a construction similar to a groyne intended to reduce the damage caused by wave action.
A building block that uses coke breeze as the aggregate.
Arrangement of bricks to ensure stability of brickwork. Examples are English Bond, Flemish Bond, Header Bond, Stretcher Bond, Garden Wall Bond Rat Trap Bond etc.
A numbered publication of the British Standards Institution describing the quality or dimensions of a manufacture, such as pipes or bricks.
The British organisation for standardising, by agreement between maker and user, the methods of test and dimensions of materials as well as codes of practice.
The facing of stone – usually of ashlar finished with a mason’s pointed chisel to give a lined finish (diagonal or horizontal).
Project built on a site previously of low value, industrial or contaminated use.
A potential construction site that has been developed or used at an earlier time.
The ease with which the designer’s details are able to be interpreted and constructed on site.
Building Energy Management System. A computerised management tool for monitoring and controlling energy usage in buildings.
The government publishes Approved Documents, which demonstrate how to the requirements of the Building Regulations may be satisfied. They are not the only means of satisfying these requirements. Other ways can include using guidance ...
Building Research Establishment Environmental Assessment Method – calculation and certification of the quality of a completed building’s energy efficiency.
Layers of roof covering, usually bituminous-impregnated rolls, laid in several staggered layers.
High-capacity electrical conductor on a consumer control unit.
A process for removing the surface of concrete to expose the aggregate and impose a fine texture achieved by mechanical hammering with a shaped bit.
A simple hinge that is let into both hinged members producing a flush finish.
A flush but unconnected joint between two similar units. When two separate boards have their edges placed against each other the joint is not the strongest of joints, however compared to other types of joints it is easy to fit.
The finishing layer of a cement render
Thickening of wall to form a vertical projection to strengthen it. See also Pier
A permanent hollow construction used underground or underwater to provide safe, dry working conditions for sub-surface constructions.
A heat exchanger that allows the transfer of heat from high-temperature water to cooler water.
The gently arched beam on its upper surface.
An upward vertical displacement built into a truss in order to compensate for deflection which might be caused by the loadings.
A strip of lead with a central groove that holds glass in a leaded light or stained glass window
The fireclay or metal terminal on top of chimneystack at end of a flue.
The SI unit of luminous intensity.
The part of a structural member of a TRUSS whichextends beyond its bearing.
A small groove typically in the underside of a sill to prevent capillary attraction across the surface.
Carbon monoxide (chemical formula CO), is a colorless, odorless, and tasteless gas. It is produced by the partial combustion of carbon-containing compounds, notably in internal-combustion engines. Carbon monoxide, rather than the more ...
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
The term used to describe a made-up window or part of a window hinged vertically to open like a door.
This is deposited in its permanent position to harden. This is the most common method of construction and when to concrete is not deposited on the ground as for roads and similar it is generally placed in temporary moulds or is ...
A steel beam formed from a standard steel section by introducing circular or hexagonal holes through the web thus reducing the dead load.
In surface water drainage, the collection area from which water is drained into the drainage system.
In surface water drainage catchpits are used to separate out heavy particles such as grit.
A hollow or concave moulding in the form of a quadrant.
The airspace between two leaves of a cavity wall
A fire protection arrangement that fits into and fills a cavity to prevent the spread of fire.
When the space between the out and inner leaf of brickwork is bridged, spanning across the cavity airspace. Causes damp patches to occur on inner face of cavity walls. usually caused by old mortar build up on wall ties
Partial Fill - Ideally there should be a free cavity of at least 50mm. If cavity insulation is intended, provision should be made to maintain this space. ‘Batts’ of insulation material are fixed to the inner leaf and if they come adrift ...
A plastic or metal unit used in cavity wall construction to tie the inner and outer leaves of the wall together.
A shaped damp proof course at the lintel of a door or window, which allows moisture to escape through weepholes
Omitting the stop ends to cavity trays or the lack of trays altogether can cause rain penetration problems around openings such as windows, doors and meter cupboards etc. In a very sheltered location the omission of these may never be ...
Usual construction for external walls comprising an inner and outer leaf with a space between for insulation and weather barrier
A wall consisting of two leaves or skins separated by a narrow cavity.
The horizontal timber in roof construction that extends across the roof tying in the ends of the rafters.
Another name for a ceiling joist.
The lowest member of a truss, usually horizontal which carries the ceiling construction, storage loads and water tank.
This is the most common type of concrete and is made mostly from portland cement, sand, aggregate and water. It is used reinforced and un-reinforced for structures, roads, foundations. The compositions of cement, sand and aggregate vary ...
The amount of cement (usually by weight) contained in a concrete or mortar mix as a proportion of the total.
A thin grout which contains cement with or without other materials.
Temporary support or formwork to an arch.
A simple method of drain comprising a holding tank which needs frequent emptying. Not to be confused with "septic tank".
A person nominated to assist a surveyor.
A corner or edge that has been cut at an angle usually 45º.
When the corner of the edge of timber is removed at forty five degrees, producing a continues flat surface at that point
A groove cut in masonry or plaster for electrical cabling or pipework; to cut such grooves
A groove cut into a wall etc to accommodate services such as electrical wiring.
The side (also called Haffit (S)). Usually the external side of a dormer window.
Small stone or slate filling in the beds and joints of masonry.
Diagonal web bracing nailed to the truss in the plane of the specified webs to add stability.
That part of a chimney construction that projects into a room.
The part of the chimney projecting beyond a roof or gable.
See Rat Trap Bond
Often referred to as "particle board". Chips of wood compressed and glued into sheet form. Cheap method of covering flat roofs and floors and often covered with Formica or melamine to construct cheap furniture, especially kitchen units
An alternative spelling for sill.
Material and components used to complete the external envelope of a framed building.
A type of grit- and dust-free aggregate, used for laying drains
cable fixing for phone wire, etc
A small bracket used to support another load-carrying member.
Hard form of felspar which rings when struck.
A pitched roof which consists of rafters tied together with ceiling ties.
In masonry, a small cut unit used to maintain the bond at openings and quoins.
Cob
Walling of damp earth sometimes mixed with cement, rammed without reinforcement into a formwork. This cheap method of walling has in the past been practiced mainly in East Anglia and the West of England
Shells of edible sea mollusc used as cheap way of producing lime by burning.
A temporary usually circular construction used to ensure safe, dry working conditions for work underground or underwater.
Soils with low or no cohesion such as sand and gravel.
Soils such as clay or silt having a high coefficient of cohesion.
A lightweight aggregate formed by a refractory process.
Caused when the cavity of a wall is bridged by a brickwork return or lintel, this can cause the transmission of cold to the inner leaf, causing a cold area where moisture can condense
Horizontal timber member designed to restrain opposing roof slopes. Absence, removal or weakening can lead to roof spread
A horizontal member in roof construction that ties the purlins to prevent lateral spreading.
A horizontal tie beam of a roof, which is joined to opposing rafters at a level above that of the wall plates
A vertical member in a structural frame.
See English Garden Wall Bond
A floor joist that spans the full width of the supporting construction.
Relatively cheap hard clay bricks that are not suitable for faced work.
The subdivision of floor areas into compartments to assist in the control of fire.
A floor construction which uses more than one structural material.
Condensation is probably the most common cause of dampness in a modern home. It occurs mainly as a result of a lack of sufficient ventilation combined with other factors which are a part of modern day living. These include cooking, ...
Circular or rectangular trunking that contains electrical wiring.
Rock composed of rounded fragments in a cement of hardened clay or sand.
A technique used in diaphragm walling whereby bored piles are constructed so that they are touching thus forming a continuous wall underground.
The top course of masonry in a wall or parapet, usually sloping or weathered.
Protective finish to the top of a wall
A projection of stone, timber, etc, jutting out from a wall to support a load.
Stepped courses of brickwork producing progressive projection
Moulding around room at junction of wall and ceiling. See also Cove
An ornamental moulding round the wall of a room just below the ceiling, or a horizontal moulded projection crowning a building or structure, especially the uppermost member of the entablature of an order, surmounting the frieze.
A tapered recess that allows the head of a screw or bolt to lie below a surface; also to cut such a recess
Sloping buttresses constructed at intervals along a retaining wall to reduce the stresses in the wall.
A type of depression, a tapered hole formed in the material that allows the screwhead to lie flush with the surface.
Eg coupled roof – a roof supported by pairs of rafters.
A roof with untied rafters pitched two ways about the ridge.
Squared stones, usually with roughly dressed faces laid in courses.
A row of bricks, blocks or masonry forming a level line in a wall.
Moulding around room at junction of wall and ceiling. See also Cornice
Cornice material made from plaster or p