The Big Guide to DIY Jargon

Ever been stumped by complicated technical terminology or DIY jargon? Not to worry - we've tackled those technical terms and delved into the DIY jargon to bring you our BIG guide to the meaning behind all that tricky lingo! Just click the image below to explore our illustrated guide to DIY jargon, or scroll down for the text version.

For more jargon-busting, check out our guide to door jargon.

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Aerate/aeration: to supply with air - often used to describe digging into soil to loosen it and allow air to enter.

Airlock: a blockage in a water pipe, resulting from a trapped air bubble. This will reduce or can even stop the flow of water.

Allen keys: small L-shape pieces of metal used for loosening and tightening certain nuts.

Amps: short for ‘amperage’; a measure for the for the amount of electricity being used.

Anodizing: a process that increases resistance to corrosion and wear in metals.

Armoured cable: electrical cable protected by a layer of aluminium or steel armour. Used outdoors and in underground systems.

Auger bit: a drill bit that includes a helical shaped screw blade; designed to remove material from the hole being drilled.

Back siphonage: a fault that occurs when negative pressure causes water to be drawn back into the water supply.

Ballast: a type of fine, coarse aggregate used in the production of concrete.

Ballcock: also known as a balltap or fill valve, this is used to fill water tanks (usually in toilets), and to prevent them from overflowing.


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Bar: metric unit of pressure.

Beam spread: a measure for the spread of light from reflector lamps.

Bevelled edges: angled edges on structures such as tiles or skirting.

Bitumen: also known as asphalt; used primarily in road construction.

Bitumen emulsion: bitumen in liquid form.

Bleed valve: used to release air that builds up inside a radiator and prevents it from functioning properly.

Boiler flue: the device that releases used gases from the boiler into the outside air.

Bolster chisel: a steel chisel with a wide blade. Combined with a club hammer it can be used to cut bricks.

Bradawl: a tool with a thin, flat end, designed to create an indentation to help the insertion of a nail or screw.

Burr: the raised, rough edge that often remains after processes such as drilling and engraving.

Butt hinge: the hinge that connects a door to its frame.

Cam fastener: the fitting that locks two sash windows together.

Candela: the SI (International System) unit of luminous intensity; a standard candle emits roughly one candela of luminous intensity.

Capillary joint: joint made by connecting two pipes with a fitting and using molten solder to fill the gap.

Casement stay: a metal bar that is used to hold casement windows open or closed.

Castor cups: small, round devices designed to stop the legs of furniture damaging floors or carpets.

Caulking tool: a tool used to press filler materials into small gaps.

Cellulose filler: a low adhesion filler for repairing small cracks and gaps.

Centre beam candlepower: the intensity of the light as measured at the centre of the beam of a reflector lamp.

Check valve: a valve that allows fluid to flow through it in only one direction.

Chamfer: when edges are cut away to create a symmetrical, sloping edge.

Chelated iron compounds: an iron complex that boosts the health of ericaceous (lime-hating) plants.

Chinagraph pencil: also known as a grease pencil, wax pencil, or china marker. Made from hardened wax for marking glossy surfaces such as porcelain, glass, plastic, and ceramics.

Circuit breaker: an automatic electrical switch that protects electrical circuits from damage caused by overload or short circuit.

Circuit pressure: the pressure at which a central heating system is operating. Some systems have a point at which they operate most efficiently, and they may stop working if the pressure goes too high or too low.

Cistern: a tank for storing water, generally used to flush toilets.

Closing stile: the vertical side of a door that meets the frame when the door is closed.

Colour rendering index: a measure of how artificial light sources reveal the colours of objects, compared to natural light sources.

Combination boiler: a boiler that simultaneously heats water and provides central heating (e.g. heats radiators).

Combustion chamber: the part of the boiler where fuel is burnt.

Combustion gases: the gases that are produced when fuel is burnt; primarily consisting of CO2 and water vapour.

Compression fittings: leak-tight fittings designed to connect two pipes of different materials.

Conduit gland: a fitting used to secure outdoor cables in a mounting box.

Consumer unit: a centralised unit for enabling or disabling electricity in the home.

Continuity tester: electrical testing equipment used to establish whether an electrical circuit can be created.

Core bit: used with a power drill to create large holes in concrete.

Corrosion inhibitor: a chemical compound that is added to a liquid or gas to limit the corrosion of a material.

Cranked hinge: a hinge that allows a door to be opened 180 degrees.

Cranked spanner: a spanner with bent jaws; used to reach tricky places.

Cranked swivel tails: tap tails that enable you to connect pipes to tap-holes in non-standard sizes.

Craquelure: the pattern that forms when old materials such as paint or ceramics crack on the surface. Sometimes recreated intentionally in furniture decoration.

Cross rail joint: a middle rail joint designed for use on hand rails and similar structures.

Cylinder lock: the most common type of external door lock.

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Deadlocking: when a door is locked so that it will only open with a key (from the inside).

Deep seal trap: the U-bend found beneath sinks and baths, which acts as a barrier from the sewage waste system.

Dimmable: a device that allows you to vary the output of a bulb.

Diplexer: a device that enables ports of different frequencies to coexist without interfering with each other.

Direct cylinder: a hot water storage cylinder that provides hot water to water outlets (e.g. taps and showers).

Double check valve: a valve that prevents backflow in order to protect water supplies from contamination.

Dovetail nailing: a system by which you improve stability by hammering two nails at an angle (towards each other).

Dowel: a cylindrical rod with grooves. Made from wood, plastic, or metal, they have a variety of uses including shelf support and as movable pieces in a toy.

Downpipe shoe: an angled pipe designed for directing water into a drain.

DPC: Damp Proof Course. A process designed to prevent damp from penetrating the inside walls of a building.

Drilling jig: a tool for controlling the movement of a drill and ensuring accuracy.

Drip loop: when external electrical wires are formed into a loop. Used to prevent rain water from running into electrical equipment.

Dry lining: a plasterboard or similar material that can be used to line a wall in place of a hard plaster. Dry lining needs less water than hard plaster, and usually, less skill to apply.

Ducting: the hose or pipe like part of a ventilation system.

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Earth clamps: clamps used to connect pipes to insulated earthing cables.

Eaves: the edges of a roof; usually forming an overhang to keep water clear from the walls.

Edging sander: a small sanding tool used specifically for sanding the floors on the edge of a room.

Efflorescence: a white deposit that forms on masonry when high humidity draws salts to the surface of the material.

EPDM seals: a type of draft excluder.

Expansion tank: part of a central heating system that’s used to protect it from excessive pressure.

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Faceplate: the exterior of a plug socket or light switch.

Fascia: the board that’s situated vertically under a roof edge (running horizontally across the roof). Often used for attaching guttering.

Feather-edge boards: tapered, wooden boards; usually used for fencing.

Filament: the very thin wire which when heated by electricity produces the light in incandescent lamps.

Filling loop: a flexible hose with valves at either end that is used to introduce water to a sealed heating system (i.e. a boiler).

Fitch fastener: window furniture used to secure wooden sliding sash windows.

Flashing tape: thin pieces of material that are used to prevent joints from letting water into a structure.

Flexible drain auger: a long, flexible device used to clear blockages in drains.

Flexible filler: a type of crack-resistant filler used in areas where small movement may occur.

Float valve: a valve that opens or closes when water levels change. Usually used in toilet cisterns.

Floating floor: a floor that doesn’t need to be nailed or glued to the floor; synonymous with laminate flooring.

Flue: the channel that removes exhaust gases from fireplaces, water heaters, and boilers.

Flue liner: a liner that can be added to a flue to prevent corrosion of the original flue lining.

Fuse: used to protect electrical circuits and appliances from excessive current flow.

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Galvanised: when metal is coated with zinc in order to prevent rust from forming.

Gauge: a device to locate the exact center of any circular object.

G clamps: g shaped devices that are used for clamping objects into place.

Gimlet: a small hand tool used to create small, smooth holes in wood.

Gland nut: the part of a tap connection that you will need to tighten.

Glazing bars: structural bars into which glass is fitted.

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Halogen light bulb: lasts twice as long and produces twice as much light as an incandescent bulb of equivalent wattage.

Hasp: a slotted metal plate that’s secured as part of a padlock.

Hexagon bush: a coupling used to join flexible supply hoses together – such as in a washing machine.

Hinge bolts: used on the hinge side of a door to prevent the door from being removed from its hinges.

Hopper head: positioned at the top of a downpipe into which wastepipes drain.

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Illuminance: a measure of how much light is illuminating a surface.

Indirect cylinder: hot water cylinder used to separate water used for central heating and domestic purposes.

Initial lumens: the light output of a lamp, based on its performance after 100 hours of use.

Isolation valve: the main valve that stops the flow of a compound (i.e. gas or water). Used generally when maintenance work is carried out.

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Joists: the supports for foundations and walls; also serve as the beams to support ceilings or floors.

Jubilee clip: a small grip that needs a screw to tighten. Frequently used on hoses.

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Keyhole angle plates: a metal plate with holes for inserting screws. Used to lock an item in place.

Kilowatt (kW): a unit of power equal to 1000 watts.

Kilowatt Hour (kWh): the measure of energy by which energy is sold. In an hour, a 1000 watt heater will use one kilowatt-hour.

Knotting solution: a shellac-based liquid applied to wood before the application of paints, waxes, or polishes, to prevent knots in the wood from leaking resin.

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Lamp: as well as meaning a lamp fixture, this is the technical word for a light bulb or tube.

Lamp properties: an umbrella term for the words that describe the functionality of a lamp; i.e. its wattage, volts, and colour rendering index.

Lintel: a support used above a door or window, that’s designed to bear the weight of what’s above it.

Live knots: knots in timber that are leaking resin.

Load bearing: a structure that is supporting weight; often used in reference to a supporting wall.

Low voltage: applies to lamps with a voltage of less than 50.

Lugs: built in projections used to secure an appliance to a wall.

Luminaire: the term to describe a lighting unit in its entirety.

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Magnetic contact transmitter: a device designed to activate when it is disturbed; usually fitted to doors and windows.

Masonry bit: a type of drill bit with a tungsten carbide tip. Used for drilling into bricks and blocks.

Masonry nails: very strong nails, designed for use in bricks and blocks.

Masonry paint: paint formulated for use on rendered exterior walls.

Masonry stud anchors: an expandable bolt used to attach timber to masonry.

Mastic: a flexible sealant.

Melamine: a type of plastic. Generally used for the surface of worktops.

Mini trunking: used to keep wires tidy and safe.

Mitred: when a surface is cut at an angle, for example in the corner of a skirting board, or on a picture frame.

Mortice lock: a type of lock that is controlled by a key moving a bolt into the striking plate in a door frame.

Mouldings: strips of wood used for decorative purposes.

Muntin: the strip (or strips) of wood or metal that divide panes of glass in a window.

Non-ferrous: metals with no iron content – this includes copper and aluminium.

Non-load bearing: a surface which is not supporting any weight; i.e. a partition wall.

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Ornate escutcheon: a decorative cover for a keyhole.

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Parquet: a type of flooring formed from small blocks of wood.

Particle board: boards made from bonded wood chips, i.e. chipboard.

Pent roof: when a roof only slopes in one direction.

Phosphor: the coating on the inside surface of fluorescent lamp bulbs, which transforms ultraviolet energy into light.

Pilot hole: the initial small hole that’s drilled into a material in order to guide and simplify the job of the larger drill.

Pilot light: a small gas flame, most often found in water heaters and central heating systems, that stays permanently alight in order to quickly ignite a more powerful gas burner.

Pitched roof: a roof formed of two or more slopes which are steeper than 10 degrees at the point at which they meet.

Plinth panel: the panel that sits alongside the bottom a unit.

Plumb line: a line with a weight suspended on the end, used to determine whether something is a true vertical.

Pointing: using mortar to finish the joints between bricks in a wall.

Porous: when a material is able to absorb liquids.

Power factor (PF): a measure for how efficient a device is at using power.

Pressure gauge: a gadget that shows the pressure of water within pipe work.

Profile gauge: a device formed of many tiny needles which can be pressed into a surface and fixed in place, in order to replicate a shape.

PTFE tape: a polytetrafluoroethylene film used to seal pipe threads. Also called ‘plumber’s tape’.

Push-fit joints: joints which automatically lock when pressed together.

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Quadrant moulding: a thin piece of timber, often used to cover gaps in between window frames and cills.

Queen closer: a brick of half the normal width; generally used to complete a course of bricks or to space regular bricks.

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Radiator valves: used to control the flow of water to a radiator and turn the heat it emits up, down, or off.

Rafter: a type of sloped beam that supports the roof of a building.

RCD: acronym for ‘Residual Current Device’; an electrical wiring device that cuts off a power supply if it detects a fault in the circuit.

Rendering: coating an external wall with cement.

Re-point: replacing cement mortar (between bricks) that may be missing or damaged.

Ring circuit: when cables are run around rooms and connected to electrical sockets.

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Safety valve: used to prevent excessive pressure; i.e. in a boiler.

Scale: the substance that forms due to hard water. Can be treated with a descaler.

Scotia beading: decorative mouldings that sit alongside the bottom of skirting boards.

Screed: usually a mix of concrete and sharp sand. Used to create smooth, level flooring.

Screw eye: a screw with a loop at the head

Sealant: a filler used to seal gaps between two surfaces; often used around baths, and showers, or between a sink and the wall.

Shavehook: a metal tool used to remove paint and other types of coverings.

Shiplap cladding: timber boards designed to overlap each other so that they become weather-tight.

Skew nailing: when nails are driven in at a slanted angle (between 20 and 30 degrees) to increase the strength of the join.

Sludge: dirt that forms on the inside of a radiator due to corrosion.

Soffit board: a board used to cover the space beneath a fascia.

Soil stack: a vertical drain pipe which carries soil waste from sanitary units; usually toilets.

Sole plates: a timber base to which vertical timbers are nailed.

Solenoid valve: an electrically operated valve used to control the distribution of fluids. Often found in appliances such as washing machines and dishwashers.

Solvent-welded joints: sealing joints together with the use of an adhesive.

Spacers: cross shaped pieces of plastic used to create small gaps between tiles.

Spokeshave: a small tool designed to shape and smooth thin, curved sections of timber.

Stabilising primer: prepares and seals porous or powdery walls before painting.

Staple: part of a padlock; used with a hasp.

Stopcock: a tap which can be used to stop the water supply to a home.

Stopend: used at the end of a lintel to stop moisture entering the inside wall.

Stress crack: damage that occurs when a fitting is over tightened or subjected to too much pressure.

Strike plate: part of a door – a metal plate, with holes in, which the door’s bolts enter as the door is closed.

Striplight: a thin, tube shaped lightbulb. Often used in bathroom mirrors and picture lights.

Stud partition: a temporary wall formed of timber and plasterboard.

Surface-mounted socket: a type of socket that sits on the outside of a wall, rather than being inset.

Surform: a type of tool with a perforated, cheese grater like base; used for shaping.

Swarf: the shavings that are produced when drilling into metal.

Swivel tap: a tap where the spout can be moved around.

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Tamping: compressing building materials with the use of a large, flat surface.

Tap spindle: the part of a tap that joins the handle to the body.

Thermal resistance: a measurement of how long an object or material is able to resist heat flow.

Thermostat: used to stop or start a boiler in order to attain a chosen temperature.

Thermostatic valve: a valve which can be used to control the heat-output of an individual radiator.

Torque: the amount of force that is applied when a spanner is used for tightening or loosening.

Two-core flex: a type of flexible cable which has just live and neutral conductors; used with double insulated appliances.

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Union clips: used to link two sections of plastic guttering.

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Vapour barrier: material used for damp proofing – generally a plastic or foil sheet.

Volt: the unit for electrical potential.

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Waterproofer: used to prevent water entering into masonry; should still allow the wall to ‘breathe’ (let moisture escape).

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Zone valve: used to control the flow of water or steam within a hydronic heating system.

  • Information is accurate at time of publishing, however, may be subject to change.
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