Glossary of terms
A special brick with holes, built into an external wall to provide background ventilation.
(see BACKGROUND VENTILATION)
ALTERNATIVE ESCAPE ROUTES
Escape routes sufficiently separated by either direction and space, or by fire-resisting construction, to ensure that one is still available should the other be affected by fire.
A special paddle shaped tread with the wide portion alternating from one side of the stair to the other. Designed to save space and used in both straight flights and spiral (circular) stairs.
(see SPIRAL STAIR)
A series of technical documents explaining the practical details in The Building Regulations and how they should be interpreted.
A plain or moulded section around a door or window opening.
The empty space in a roof.
Permanent ventilation consisting of airbricks, grilles and hit-&-miss ventilators, required in all habitable rooms under the Building Regulations.
One of several vertical members used to infill a balustrade.
A protective barrier on a staircase formed by a series of balusters capped by a handrail. The height of balustrades and spacing of balusters are given in Approved Document K.
(see BALUSTER, HANDRAIL)
A small sawn timber section fixed across the rafters on a roof to provide support for tiles or slates.
(see COUNTER BATTEN)
A long timber, steel or concrete member designed to carry loads over a span between supports.
(see SPAN, DEAD LOAD, IMPOSED LOAD)
A timber joist spanning across the ceiling joists to strengthen them.
Insulating material loosely compressed into a flexible slab or blanket. eg. glass fibre or mineral wool.
A roof structure in which the rafters are covered externally with boarding before the roofing felt and tile/slate battens are fixed.
A simple square frame made from four members (usually timber) joined together at to each other. e.g. around an opening for a loft access hatch* or a roof window*.
BUILDING ACT 1984
The statutory Act of Parliament that controls the safe construction, extension and alteration to all building in England, Wales and Ireland.
BUILDING CONTROL BODY
A term used to include the local Authority Building Control department and its Approved Building Inspectors.
see BUILDING INSPECTOR)
An official of the Local Authority Building Control department, who inspects building work to ensure it complies with Building Regulations.
The detailed rules of construction as specified in the Act and explained in the Approved Documents. (except in Scotland and Northern Ireland which have different legislation)
The soffit of any floor (above the ground floor) in a building which is exposed overhead and may be integral with the floor structure, or suspended below it.
(see SUSPENDED CEILING)
A 'U' shaped section, usually of steel, used as a structural support.
The space between two adjacent surfaces, close together but not touching. eg., a door or window and its frame.
COLD WATER STORAGE CISTERN
An open-topped tank to store water from a rising main and fitted with a ball-valve and overflow pipe.
CONCERTINA LOFT LADDER*
A special ladder designed to collapse down when not required and so save space.
Water droplets deposited from warm, damp air when it comes into contact with any cold surface.
A rigid tube or duct to carry and protect electrical, telephone and computer wiring.
Any area of natural beauty and resources which requires protection, preservation and sustained management. eg. The National Parks, The Broads etc.
The assembly of separate fuses with an isolation switch in a protected enclosure, connected to the incoming electricity supply.
(also known as a FUSEBOARD)
A small sawn timber section fixed over a boarded and felted roof in the opposite direction to and providing support for the tile/slate battens and allowing natural ventilation.
The Department for Communities and Local Government (which now supercedes the ODPM - Office of the Deputy Prime Minister)
The load due to the weight of all walls, permanent partitions, floors, beams, roofs and finishes including services and all other permanent elements of construction.
(see IMPOSED LOAD)
An alternative to a door frame in a stud partition, which uses a section of 25mm (nominal) timber to the full thickness of the partition.
A structure projecting above the roof slope to let in light and provide ventilation to a loft conversion and also to provide additional headroom.
(see ROOF WINDOW)
A fungal growth that attacks and destroys timber by absorbing its moisture. It also has the ability to spread rapidly and, if untreated, can cause serious damage to the building structure. Dry rot is usually caused by poor ventilation.
(see WET ROT)
A term from the USA/Canada, to describe the construction of stud partitioning covered with plasterboard.
(see STUD PARTITION, PLASTERBOARD)
The lowest part of a roof around its periphery, which projects beyond the face of the wall below.
Any route forming part of the means of escape from any point in a building to the final exit.
(see FINAL EXIT)
A special Loft Shop window that opens as a casement and meets the requirements of the Building Regulations.
(see also Approved Document B)
A price given by a builder or trade company which is approximate. Not to be confused with a Quotation.
(see TENDER or QUOTATION)
An open ended pipe designed to discharge over-heated water from a hot water cylinder and which usually terminates over an expansion tank.
(see OVERFLOW PIPE)
EXPANSION TANK or HEADER TANK
A small open-topped cistern (tank) containing water with which to top up a central heating system.
Any means of extracting stale air from a bathroom or kitchen.
(see PSV, also Approved Document F)
A vertical board or trim fixed along the eaves to cover the ends of the rafters and on which to fix the gutter.
(see GUTTER, RAFTER)
Felt sheet soaked in bitumen and used over the rafters to line the roof before the tile/slate battens are fixed.
The termination of any escape route from a building giving access to a passageway, street or open space and sited so that persons are not in any danger from fire or smoke.
see FIRE RESISTANCE)
The actual size of a timber member after it has been machined. e.g 50mm x 100mm nominal timber will machine to 45mm x 95mm actual size.
(see PAR TIMBER, SAWN TIMBER)
A door designed to withstand the passage of fire for a given period of time. eg. an FD20 door will resist fire for 20 minutes.
The ability of any component of construction to satisfy, for a stated period of time, some or all of the criteria specified in the relevant part of BS.476.
Any weatherproof material, usually galvanised steel or lead, used to cover the gaps between two adjoining materials, for example on a roof or chimney stack or around openings such as doors and windows.
The series of consecutive treads and risers which make up a stair.
(see TREAD, RISER)
Any element of construction or finish with at least one face that does not project beyond the face of any adjacent element(s).
(see EXTRACT VENTILATION)
(see CONSUMER UNIT)
The triangular upper portion of a wall below the ends of the roof slopes.)
The horizontal distance between the risers of two consecutive stair treads.
(see TREAD, RISER and also Approved Document K)
A safety rail fitted around an opening in a floor (eg. a loft access hatch) or where there is a change of level.
A room used, or intended to be used, for dwelling purposes, including a kitchen but not a bathroom.
The member fitted along the top of a stair balustrade to provide support for any person using the stair.
An opening in a ceiling to provide access into a loft space and usually fitted with a hatch door.
The top member of a stud partition or the frame of a lining around a door or window.
(see STUD PARTITION)
HEAD OF WATER
The vertical distance between the water in a storage tank or cistern and any appliance it feeds. eg. a shower which will require sufficient 'head' of water for it to operate correctly.
The clear height in a room or doorway to allow a person to stand without bending
The junction between the two outer slopes of a pitched roof.
Rolled Steel Joist. A structural member with a central spine and two flanges in the shape of a letter 'I'.
The load produced by the intended occupancy or use, including the weight of all movable partitions, furniture, persons, distributed, concentrated, impact and snow loads, but excluding wind loads.
(see DEAD LOAD)
The side members of a frame or lining around a door or window.
A structural member of timber or steel and spanning between supports and designed to carry loads.
The distance between joists (in a floor or ceiling) measured from centre to centre of each one.
A metal bracket designed to support the ends of timber joists where they cannot be built into the supporting wall or other structural element.
An enclosed box in which electric cables are joined together.
An arrangement of treads supported by side members and used as a means of access from one level to another. eg. a Loft Shop Loft Ladder.*
A level platform at the top of a flight of stairs or at a change of direction in a stair.
LATH & PLASTER
The traditional method (now obsolete) of covering walls and ceilings, in use until the 1950‘s (approx) when it was replaced by plasterboard sheeting.
(see DRYWALL, PLASTERBOARD)
A timber, steel or concrete structural member used to span an opening and support a load. eg. over a window or door.
(see IMPOSED LOAD)
Any structural part of a building designed to carry imposed loads. eg. a brick or concrete wall, steel or concrete pillar or timber, steel or concrete floor.
LOFT or ATTIC
The space below the rafters in a roof and above the ceiling, which may be of use as habitable space.
LOOSE FILL INSULATION
Insulation, such as mica pellets, used for heat insulation around hot water cylinders and between ceiling joists.
(Miniature circuit breaker) A fuse device that operates in micro-seconds to break the electrical circuit and prevent electrocution.
MEANS OF ESCAPE
A protected route used in the event of fire to provide egress for persons to a place of safety.
MINIATURE CIRCUIT BREAKER
A special 'means of escape' roof window which complies with the dimensions set out in the Building Regulations
(see Approved Document B)
The square or round block on the top of a newel post, sometimes fitted with a decorative finial.
A post supporting the strings and balustrade of a stair.
A short horizontal member fitted between the studs in a framed partition.
(see STUD PARTITION)
The front edge of a stair tread, often rounded.
A stair in which all the vertical risers are omitted.
An open-ended pipe designed to discharge water from a tank or cistern when it oveflows. eg. a toilet cistern.
Any material used to fill a gap between two adjacent surfaces.
PAR (planed all round) timber which has been machined on all four faces to precise dimensions. eg.. 50mm x 100mm sawn timber will reduce to 45mm x 95mm (approx) after machining PARTITION.
(see STUD PARTITION)
A wall built on the boundary between two buildings (as in semi-detached houses) which is common to both and subject to legislation in the Building Regulations and The Party Wall etc. Act 1996
The degree of slope of a structural member or roof especially when expressed as the ratio of height to span. (i.e, a 30° pitch.)
A roof with a slope greater than 150 to the horizontal.
The approval required from a Local Authority for permission to do work on any building under the Town & Country Planning Act 1962.
A sheet material consisting of compressed gypsum plaster between two sheets of tough building paper.
A transparent unbreakable thermoplastic resin used for Loft Shop domed roof lights.
A stair that discharges to a final exit and place of safety, and is adequately enclosed by fire-resisting construction.
(see FINAL EXIT)
'Passive stack ventilation' is a system of ventilation that uses ducts from the ceilings of rooms to terminals in the roof and operates by a combination of the natural movement of warm air, and the effect of wind over the external surface of the roof.
(see also Approved Document F)
The horizontal timber or steel beam which provides support for the rafters in a roof.
One of several parallel sloping timber or steel members which form the roof of a building.
The horizontal member fitted between the two vertical stiles in a framed and panelled door.
A sloping surface connecting two other surfaces at different levels.
A permanent method of ventilation, such as a window, that provides a natural flow of air.
(see also Approved Document F)
A 'residual circuit device' fitted to an electrical supply for safety and breaks the circuit in micro-seconds to prevent electrocution. An RCD will protect all the circuits fitted with MCB’s in a consumer unit.
The apex of a pitched roof at the junction of two slopes.
The horizontal timber member which spans the length of the roof and supports the ends of the rafters.
RING MAIN or RING CIRCUIT
(see CONSUMER UNIT)/p>
The vertical distance between two consecutive treads in a stair.
(see GOING, also Approved Document K)
The vertical member which separates and connects the treads in a stair.
RISING BUTT HINGE
A special type of hinge which operates as a self-closing mechanism when a door is open.
The supply of mains water to a building which usually terminates in the roof in a cold water storage tank.
(see COLD WATER STORAGE CISTERN)
A clear plastic dome (normally made from polycarbonate) with or without
A dome light, lantern light, skylight, ridge light, glazed barrel vault or other element intended to admit daylight through a roof.
(see ROOF DOME, ROOF WINDOW*)
A framed assembly of structural members consisting of ceiling joists, rafters, struts and ties. Not to be confused with trussed rafters.
(see TRUSSED RAFTER)
An opening window fitted into the roof slope and parallel with it. Also available as an alternative means of escape MOE* window.
(see MOE WINDOW, also ApprovedDocument B)
A felting sheet laid over the rafters to provide a weatherproof barrier under the tile/slate battens.
The opening part of a casement or sash window into which the glazing is fixed.
Timber in its rough state prior to being machined. Sawn sizes are nominal, whereas machined sizes are actual and. referred to as PAR.
(see FINISHED SIZE, PAR TIMBER)
A horizontal member made of timber, brick, stone or concrete onto which a door or window frame is fixed.
A method of nailing at an angle when constructing stud partitions.
A narrow timber member fixed around the base of internal walls to protect the wall finish from being kicked or damaged. In a kitchen or bathroom the skirting can also be of tiles.
A window inserted in a flat or pitched roof to provide natural light to the room below.
(see ROOF WINDOW)
A fine-grained rock capable of being easily split into very thin layers and used for roofing and flooring tiles.
The underside of an overhanging part of a building, typically between the fascia board and the external wall and below the roof.
A pipe designed to carry away effluent from bathrooms and kitchens on one or more floors of a building.
(see SOIL VENT STACK)
SOIL VENT STACK
A pipe designed to carry away effluent from one or more floors of a building, which terminates above the eaves level of the roof and provides ventilation to the foul water drain into which it discharges.
(see SOIL PIPE)
The clear distance between two supports or bearings measured along the length of a structural member
A staircase with tapered treads assembled around a central column. Also referred to as a helical stair.
STAIR or STAIRCASE
A structure made from a series of steps held between and fixed to two side members (strings) to provide access between two different levels.
(see RISER, TREAD, STRING, also Approved Document K)
STRING or STRINGBOARD
The two structural side members of a stair into which the treads and risers are fixed.
(see TREAD, RISER)
A metal bar designed to hold a window sash in the open or closed position.
The two vertical side members which make up a framed and panelled door.
A structural member designed to resist compression stresses and used in a roof to support the purlins.
A vertical timber used in the construction of stud partitions.
A series of vertical studs and horizontal noggings nailed together to form a framed partition and usually covered with plasterboard on both sides.
(see DRYWALL, STUD, NOGGING)
A non-structural element fixed below the soffit of the structural floor, and which lowers the height of the room and may contribute to fire resistance.
(see CEILING, also Approved Document B)
A closed cistern similar to a hot water cylinder but rectangular. Often mistakenly termed a cistern.
A stair tread that is wider at its outer edge and used in spiral stairs.
The Town & Country Planning Act, 1962, a statutory Act of Parliament which controls the planned development of both rural and urban areas in the UK. www.tcpa.org.uk
An exact pattern used as a master for cutting repetitive and awkward shapes such as alternating treads.
(see ALTERNATING TREAD)
TENDER or QUOTATION
A firm price given for work by a builder or trade company. Not to be confused with an estimate.
A measure of the rate at which heat passes through any material or structure and expressed in watts per metre thickness per degree of temperature difference ( = W/m/K)
(see also Approved Document L)
(see ‘U’ VALUE)
A structural member designed to resist tension stresses and used in roof trusses.
A durable weatherproof material used for roofing and normally made from burnt clay, or concrete with integral nibs on the lower side which hook over the tile/slate battens.
Any horizontal member fixed across an opening such as a window frame.
The bend in a waste or soil pipe which forms a water-seal to prevent foul gases escaping into the building. Traps are designated 'P', 'S' or 'U' according to their shape.
An access door into a loft space usually hinged and fixed into a frame.
The horizontal member in a stair that separates and connects the risers.
A structural member normally of timber which spans between two other structural members to form an opening. eg. for a stair or ladder.
A method of roof construction (post 1960) using pre-fabricated triangular frames made with small section timbers fixed together with metal plates. The frames are placed at regular intervals (normally 600mm) along the supporting walls of the building and replace the traditional purlin and rafterconstruction.
The ‘U’ value or thermal transmittance is a measure of the rate at which heat passes through one metre° of any material or structure, when the air temperature on either side differs by one degree. The value is expressed in watts per metre square temperature difference. (U = W/m2 /K)
(see also Approved Document L)
The junction between the two inner slopes of a pitched roof which form the valley gutter.
Any means of ventilation which opens directly to the external air, such as a window, door, airbrick, or louvred ventilator.
A load bearing timber member laid on top of a structural wall onto which the floor, ceiling and rafters members are fixed.
A pipe which carries waste water from a basin, bath or sink and either discharges over an external gully or into a soil stack.
(see SOIL PIPE, SOIL VENT STACK)
A tapered tread which allows a change of direction in a stair and used where space is restricted.
Definitions are taken from The Oxford Dictionary, Collins English Dictionary and the Building Regulations Approved Documents.