A particulate material which is made up of sand or crushed stone. Aggregates are used in materials such as concrete and are a fundamental part of building foundations.


A perforated brick used for ventilation, especially for under floor spaces.


A fibrous mineral used in the past for insulation. Can be a health hazard - should not be disturbed and specialist advice sought if found or suspected.


Black, tar-like material, strongly adhesive and impervious to moisture. Used on flat roofs and under tile felt.



The bill of quantities is a contract document that contains a list of materials and workmanship involved in a construction project. It is necessary for properly pricing a project.



A grey or white powdery material which is mixed with an aggregate and water to make mortar or concrete. A chemical reaction of the cement will cause the mixture to harden.

Chromate Primer

A paint used for priming aluminium, galvanised and other metal surfaces.

Circuit breaker

A switch in the electrical panel that shuts off power to certain parts of the building.

Collar (in pipes)

The wider end of a pipe into which another pipe fits.


A building material created by a hardened mixture of cement, gravel, sand, and water. It is used for slabs, columns, and other types of structures.

Coping stones

Stone or concrete slabs laid on top of a masonry wall as a decorative finish and to shed rainwater. The coping stones are normally wider than the wall to allow an overhang on both sides of the wall.


A decorative moulding at the junction between a walls and ceiling of a room, or the uppermost horizontal moulding of a classical entablature.


To insert a suitable screw into a surface so that its head does not protrude above that surface. This is achieved by using screws in a hole 'counterbored' with a flat bottomed cutter. If the counterbore is deep enough, it may be plugged with a piece of doweling to fully hide the screw head.


To insert a suitable screw into a surface so that its head does not protrude above that surface. This is achieved by using counter sink screws in a hole 'countersunk' with a conical-shaped cutter.


A row of bricks, concrete blocks, etc in a wall etc.


A curved moulding at the junction between a walls and ceiling of a room - a form of cornice.


Damp-proof course (DPC)

A layer of impervious material inserted towards the base of walls to stop rising damp. In older buildings, slates was used, more modern practice used mineral felt or PVC. A new DPC can be inserted where necessary, a "chemical" form of silicone being injected into the walls.

Damp-proof membrane

Normally a layer of plastic sheeting, laid over the site hardcore of a modern building, to prevent moisture rising from the ground into the floor structure. Needs to be connected to the DPC in the surrounding walls to be fully effective.

Double glazing

A method of thermal insulation applied to windows usually either using:


• Sealed units using two panes of glass hermetically sealed with internal air gaps. or


• Secondary glazing where a single pane of glass is fitted inside an original single glazed window, usually fitted to the window frame.


The pipe used to take water from the guttering to the drainage system. Usually round or square cast iron (on older properties) or plastic - may be Asbestos Cement.


Piping that carries air throughout a structure.



The white powdery deposit on the surface of masonry or plaster caused by mineral salts migrating to the surface as a result of moisture evaporation. Harmless but unattractive.

Engineering brick

A strong and dense type of brick, impervious to water so ideal for use in damp areas.


Floor plan

The floor plan refers to the layout of the building. It is a drawing of the horizontal section that shows how the different spaces relate to each other.


Normally concrete, cast into the sub-soil as the structural base for a wall or building - the depth and size will depend, amongst other things, upon the size/type of building and the nature of the sub-soil. In older buildings, the foundations may just be a course or two of wide bricks or stone.



The main horizontal support of a structure that supports smaller beams.


The collecting channels at the lowest point of a roof for collecting the rainwater. Usually cast iron (on older properties) or plastic - may be Asbestos cement. Various profiles are available; the two standard traditional ones being Half-round (with a semi-circular section and supporting brackets fixed to the fascia) and Ogee (a moulded pattern with a flat back, where it is made from cast iron, lengths are secured to the fascia by fixing screws through the back).



An abbreviation that stands for heat, ventilation, and air conditioning.



A beam that has a cross-section that looks like the capital letter I. Girders often have an I-beam cross-section.


Material that’s designed to prevent heat from leaving or entering a building. Insulation material is placed within the walls, ceiling, or floor of a structure.

Interlocking tiles

These, unlike plain tiles, are designed so that their edges fit mechanically one with another, to provide a weather seal.



The location where the surfaces of two components are joined.


King stud

A framing member that runs from the bottom to the top of a panel or sheet.



A metal wire on the frame of a building that serves as a base for laying down stucco or plaster.


A horizontal beam of timber (in old properties), stone, concrete or steel (the most common modern practice) spanning doorways and window openings in a wall to support the structure above.


Liquid Petroleum Gas or Propane. Used in areas without mains gas, requires an on-site storage tank.



In masonry, mortar is the paste that is used to bind stones, bricks, and other similar types of units used to construct the walls of a building. Mortar can be made up of a variety of things, such as asphalt, pitch, or clay.


Particle board

A substitute for plywood that is composed of sawdust mixed with resin.


A 'sandwich' of plaster with paper/card on either side. Widely used for ceilings and walls etc.


A panel of wood that is made from multiple layers of veneer, compressed together.


Short for polyvinyl chloride, this common plastic is used most commonly for water pipes and sometimes for flooring.



A series of roof frame pieces that are connected to the supports and hold up the roofing and sheathing.

Reinforced concrete

Concrete that is strengthened by adding steel bars or mesh within the concrete.

Rising damp

A building defect resulting from moisture soaking up a wall from the ground by capillary action in the structure - can lead to rot in timbers, plaster decay, decoration failure etc.



Final, level, smooth surface of a solid floor onto which the floor covering is applied - usually of mortar, or fine concrete.

Self-levelling compound

A special compound poured over an uneven floor to produce a level surface.

Septic Tank

A sewage disposal system normally consisting of two or three linked chambers within which bacterial processes breakdown the effluent, the final result being a liquid which can be fed into a land drain or soakaway. Occasional emptying of the chambers may be necessary, but depends upon their usage and the soil conditions. Care needs to be taken on what is fed into a Septic Tank - use of chemicals such as bleach, biological washing powders etc can cause the bacterial processes to stop. Not to be confused with Cesspit.


A sloping projection below a window or door opening to allow rainwater to run off.


Material that covers up the joint between the floor and a wall in the interior of a building, for aesthetic purposes.


An arrangement for draining rainwater into the ground. Usually a large hole dug and filled with broken bricks, rubble or similar 'waste' materials into which the rainwater is piped. Its effectiveness largely depends upon the type of soil surrounding the hole.

Spirit Level

A tool used to establish true vertical and horizontal lines by looking at a bubble in spirit filled vials.


A material made from aggregates, a binder, and water. It is often used as a decorative coating on walls and ceilings.


Tie bar

Heavy metal bar passing through walls to brace a structure suffering from structural instability. The ends are often visible outside a building by the large metal 'S', 'X' or circular plates which spread the load over the external walls.

Tiler's spike

A sharp pointed tool for scoring through the glaze of ceramic tiles prior to cutting.


The materials used to provide a clean finish of the building, such as moldings around window and door openings, or the baseboards in rooms, for example.

Triple glazing

A type of window providing thermal insulation by using three panes of glass hermetically sealed with two internal air gaps.



A very thin sheet of wood. It is typically a finer wood that is used as a decorative cover for lower-quality wood.

Vinyl Flooring

A soft flexible and cushioned flooring available in sheets or tiles.



A distortion of material, which can be a sign of water damage.



A government regulation that involves restricting how a property is used. For example, industrial buildings cannot be constructed in areas zoned solely for residential.