101 Common Building Terms

As building language is sometimes not so straightforward to the general public, we have created a list of some of the most commonly used building terms that builders use and that you probably have already heard.

(In approx. alphabetical order):

Architraves: Profile Extrusion/Moulding (usually timber) fitted to the surrounds of internal doors but sometimes windows

B.S.: Abbreviation for “British Standard” (but often replaced by a EU standard pre Brexit)

Barge Boards: (Gable boards/Gable Fascias) Boards (originally timber) that are fitted onto gable ends of roof.

Base coat plaster: Thick layers 10-15mm of plaster to prepare walls for a finish

Blinding: In floors (usually concrete) bedded and in contact with the ground – a layer of normally soft sand, laid down to prevent stones puncturing polythene DPM although.

Block & Beam: Concrete suspended floor, made up of pre-stressed concrete beams and concrete blocks laid between.

Breather Membrane: A material that allows vapour to pass one way but is impervious to water droplets.

Boxing: Casing normally fitted around pipes/ waste pipes.

Bulkhead: Boxing in at high level that reduces ceiling height.

Building Control: Usually Council Authority (but could be private) that inspect the works, and can insist on additional works being carried out if they see fit, their job is to make sure all building works are carried out to the latest regulation.

B.C.O. Abbreviation for Building Control Officer.

Chipboard flooring: Normally Tonged and Grooved (T&G) all joints to be glued; can be moisture resistant and have a 40 day weather protective coating for construction purposes.

Combined Sewer: This takes both Foul and Surface Water Drainage down the one pipe

Contingency Figure: Normally used on works that a price cannot be worked out on at the time of pricing the works, this is often used when there is a chance additional works* maybe needed but cannot be determined until works have been started. *eg missing insulation in an existing roof or unknown extent of existing drainage.

Coving: Normally a plaster moulding, fitted to perimeters of room where wall abut ceilings.

Crocodile Tie: product name for a metal ladder sties used instead of “Toothing Out”

DPC: Abbreviation for “Damp Proof Course” that is fitted in walls to stop rising damp.

DPM: Abbreviation for “Damp Proof Membrane”. This is used to stop damp, mostly used under a floor (usually concrete) to stop rising damp.

Eaves: The over-hang of gables or gutters and fascias.

Fascia: Board (originally timber) fitted to the end of rafters that the bottom tile sits on and the guttering is fixed to.

Floor Slab: Ground bearing floor normally concrete.

Foul Drainage: Sewage and waste water drainage from toilets baths and sinks etc.

Gable: Usually a triangular shaped top part of wall at roof end.

Gable boards: (Gable Fascias/ Barge Boards): Timbers that are fitted onto gable ends.

Gauge of polythene: often used for the DPM which needs to be of a high quality and certain thickness. 1000 – 1200 gauge is commonly used.

“The thickness of polythene sheeting is expressed in gauge or microns. Gauge was the traditional imperial measurement of polythene thickness, which has now been replaced by micron as the European metric standard. The higher the gauge/microns the thicker the polythene. The gauge of polythene can easily be converted to a micron measurement by dividing it by four. Furthermore, if you want the thickness in millimetres then just divide the gauge by 4000. As an example, 1000 gauge = 250 micron = 0.25mm.

Gluelam Beam: This is a large timber beam normally fitted to carry loads, the beam is constructed from many smaller pieces of wood glued together. The reason for this is there is less chance the timber will twist or warp as the grain is not all going the same way.

GRP: Glass Reinforced Plastic – a multilayer of fibreglass and resin with a finish colour used mainly on roofs and canoes.

Hangers: Timbers normally fitted in roof, timber fitted from rafters to form the ceiling and tie the roof together.

Hardcore: Waste masonry, normally broken bricks or concrete used as base level under concrete.

Kingspan/Celotex: Manufacture names for Foil faced foam Insulation board, twice as insulating than other insulations Mineralwool or Expanded Polystyrene Insulations.

Lintel/Lintol: Beam across top of an opening in a wall can be concrete, steel or timber etc…

Mineralwool/Rockwool: a fluffy blankest that can be formed in rolls or slabs for wall and roof insulation. Not normally load bearing so rarely used for floors.

Noggin: horizontal timber or steel in a partition stud wall

OSB/OSB3: Orientated Strand Board made from shavings of wood. OSB3 is more durable and is a good backing for Glass Reinforced Plastic (GRP) external finishes

Outer Leaf: Most external walls in the UK are cavity walls (two walls with void or insulation between). The outer leaf is the external one of the two walls – often the visible finished brick part of the wall.

Padstones: Pad made to site steel beams or large timber beams, these are built to prevent the weight of the beam and its load crushing the walls. The pad stone is normally constructed out of engineering bricks or cast concrete.

Provisional Sum: normally used as a sum that has been allowed for items that cannot be priced at that time of quotation, normally this is because there is not enough information to gain a price and is often used on items such as sanitary-ware, kitchens, doors, where the client has not had time to sort out the exact items required.

Pre-stressed concrete beams: reinforced concrete beams that have reinforcing wires kept in tension whilst the beam is being made. Bison is a manufacturer. Thin 65mm concrete lintels are usually pre-stressed.

Purlin: Timber or steel normally fitted in gables and run along the roof parallel to the ridge of roof rafter, to support the centre span of rafter.

Ridge: Top line of a pitched roof.

Rafters: Timbers fixed in roof to form the sloping area of roof.

Raised tie: Roof where you have the ceiling timber raised into the roof.

Reclaimed: Normally used with bricks, tiles and timbers that have been reclaimed from old buildings for reuse.

Seconds: Usually Bricks that are not good enough for facing bricks and sold at a cheaper price. They normally are used where they will not be seen, such as in foundations. Sometimes misshaped bricks can be used to form unusual features

Render: An external finish to walls that is applied wet traditionally this is a sand and cement plaster, but many special types are available

Restraint straps: Normally used with gable restraint straps or wall plate restraint straps. Gable restraint straps are used to restrain the gable walls by fixing them into roof and the wall plate restraint strap is for holding down the roof to the walls.

Rockwool/Mineral Wool: a fluffy blankest that can be formed in rolls or slabs for wall and roof insulation. Not normally load bearing so rarely used for floors.

Roof vents: These are a form of vent to ventilate the root and can be fitted in the soffit, on top of fascias, in the ridge, in a roof tile and in the gables.

RSJ: Rolled Steel Joist – Old size of UB still in common use

RWP: Rain Water Pipe

Skim coat plaster: Thin layers 2-3mm of plaster to finish walls.

Skirting: Moulded (usually timber) fitted to perimeters of rooms at base of walls.

Stud: vertical timber or steel in a partition stud wall

Soffit: The over-hang of a roof that is at the base of the roof (not the over-hang of gables) thus nearly the same as Eaves. Can also be used to mean the underside of a bulkhead or beam.

Surface Water Drainage:  Rain water, normally used in the context of water that runs off the roofs via RWP`s and driveway etc. if this runs into the same drain as the Foul Drainage this is a Combined Sewer

Strip foundation: This is where the foundation is excavated and a strip of concrete is laid normally only about 900 mm deep 750mm wide and 225 mm thick and then is bricked/blocked up to ground level.

Trench Fill: foundations normally 450mm wide trench filled with concrete up to about 150 mm below ground level.

Sub-soil: Soil beneath top soils.

SVP: Soil Vent Pipe – takes drainage from Toilet etc…

Toothing Out: Normally done where new walls run flush with an existing wall and it is required to cut out some of the old bricks so the new bricks can be bonded into the existing. This is done so you do not end up with a straight joint to the area where new walls abut old, (can also be called “stitching”). This can look very messy if not done well with exact match bricks this but joints with metal ladder ties are often used one manufacture is Crocodile

Trusses: Roof trusses are a pre-made section of roof usually at 3-6m centres

Trussed Rafters: Roof trusses are a pre-made section of roof usually at 600mm centres

U-Value: This is terminology for measuring heat loss. New buildings must obtain certain U-Value to comply with the latest building regulations. This is mainly used with reference to heat loss through windows, walls, floors and roof. Less than 0.2 U- value is good for walls roofs and floors & less than 1.6 U- value for Doors and Windows is good.

Universal Beam: (UB) I shaped Steel beam normally used as a lintel to carry a load over an opening.

Universal Column: (UC) as (UB) but almost same dimension in two directions in section

Vapour barrier: (VB) Barrier to stop the vapour in the air passing through the building fabric, commonly used on the form of aluminium foil on dry linings (plasterboard and insulation) walls to prevent the moisture in the air passing through insulation and causing condensation on a cold surface. This also is often used on ceilings and timber floors.

Vegetation soils: Top soils. Top soils are soils still decaying and therefore should not be built on as the soils will decay in time causing subsidence.

Wall Plate: Timber fitted to tops of walls, for roof to be fixed to – these are normally strapped down to the wall below,

Warm Roof: This is a method of fitting an insulation board to the top side of roof construction (under felt). Provided there is a vapour barrier, this avoids the need to ventilate the roof beneath.

Weather Rail: Timber moulding fitted to bottom of external door that opens inwards. This is to shed water away and stop it driving under front door.