DIY and plumbing jargon driving you round the bend? Find out what it means here…

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ABS – A strong and rigid plastic material that combines the best qualities of Acrylics, Butyrate and Styrenes. It is commonly used in shower trays due to its durability.

Acrylic – A plastic material commonly used in baths. It’s easy to mould, stays warm to the touch and is highly durable, minimising staining or scratches.

Airlock – A blockage in a pipe caused by a trapped air bubble.


Back-siphoning – A potentially hazardous situation where water flows back into the mains water system, e.g. from a toilet, shower or hose.

Back to wall toilet – A floor mounted toilet where just the pan is visible. The cistern is usually concealed behind a wall or unit.

Back to wall unit – A furniture unit used to conceal a cistern for a back to wall toilet.

Ball cock or Float valve – A valve that controls the flow of water into a tank or cistern. The valve is operated by a ball that floats on top of the surface of the water, so when the water reaches a certain level, the flow is shut off.

Ball valve – A type of quarter-turn valve, which uses a pivoting, hollow ball to open or close flow through a pipe.

Bar – A unit of measurement for water pressure. 1 bar is equivalent to the force required to push water up to a height of 10 metres. E.g. To push water 1 metre requires 0.1 bar of pressure.

Base coat – A flat coat of paint over which a layer of glaze is applied.

Batten – A narrow strip of wood, usually fixed to a wall or floor to act as a support for a unit or shelving.

Bevel – Any angle at which two pieces of wood meet, other than a right angle.

Body jets – Small shower heads that are usually set into a wall, designed to spray the body, as opposed to an overhead shower.

Bore – The hollow part of a pipe.

Bottle trap – A type of trap used with basins. A bottom part can normally be removed for cleaning or maintenance.

BTU (British Thermal Unit) – The heating output required to heat a particular sized room. It can be worked out using this equation: Room height x room width x room length (in feet & inches) = Total x 5 = BTU

Butt joint – A simple joint where two pieces of wood are fixed together with no interlocking parts cut in them.


Cam and stud fixing – A simple fixing used in flatpack construction.

Cap-nut – A nut used to tighten a fitting onto pipework.

Cavity wall – A wall made of two separate, parallel masonry skins with an air space between.

Ceramic disc technology – Used in taps, a ceramic disc is now used instead of old-style washers, needing only a quarter turn of a handle to turn the water flow on or off.

Chamfer – A flat, narrow surface along the edge of a workpiece, usually at a 45⁰ angle to any adjacent surfaces.

Chase – A groove cut in masonry or plaster for electrical cabling or pipework.

Chrome or Chrome plating or Chromium plating – A thin layer of chromium applied to a surface to help prevent corrosion and improve both appearance and maintenance.

Cistern – Normally found as part of a toilet, the cistern is a container designed to hold water at atmospheric pressure, used for the flushing system. Most commonly fitted with a float operated valve.

Close coupled toilet – The most common type of toilet found in the UK, where the cistern is situated directly above the pan - “closely coupled” together – hence the name.

Cold water storage tank or Header tank – Normally found in the loft, it’s a tank for holding water that feeds into a home water system.

Combination boiler or Combi boiler – A combined central heating and water heating unit used in homes. It doesn’t store hot water but heats water as and when required directly from the cold water supply.

Concealed cistern – A toilet cistern designed to be used with a wall hung or back to wall toilet, concealed behind a wall or unit.

Contemporary - A style of interior decorating that contains the latest styles and trends to give an up-to-the-minute look.

Counterbore – A tapered recess that allows the head of a screw or bolt to lie below a surface. Also to cut such a recess.

Countersink – To cut a tapered recess that allows the head of a screw or bolt to lie flush with a surface.

Counter top basin - A freestanding basin that sits on top of a vanity unit or counter top.

Cup – To bend as a result of shrinkage. Usually referred to as across the length of a piece of wood.


Damp-proof course (DPC) – A layer of impervious material that prevents moisture rising through a floor or in a wall.

Double ended bath – A bath where the taps are situated on one side (so there is no “tap end”).

Drain-waste-vent (DWV) system – Plumbing that removes sewage and waste water from a building, whilst regulating air pressure within the pipes.

Dual flush – A toilet cistern with the option of a smaller, water-saving flush or a full flush. These are most commonly 3 and 6 litres in volume.


Earth – A connection between the earth or ground and an electrical circuit. Also a terminal to which this connection is made.

Earth bonding – Required by law. All metal parts in a plumbing system must be connected to earth to prevent any electrical conduction. This can be achieved by using an earth bonding strap.

Electrical heating element – used in electric showers to heat water as it flows through the unit.

Extension lead – A length of electrical flex for the temporary connection of an appliance to a wall socket.


Face edge – A woodworking term for a surface that is planed square to the face side.

Face side – A woodworking term for a flat, planed surface from which other angles and dimensions are measured and worked.

Fence – An adjustable guide to keep the cutting edge of a tool a set distance from the edge of a work piece.

Float valve or Ball cock – A valve that controls the flow of water into a tank or cistern. The valve is operated by a ball that floats on top of the surface of the water, so when the water reaches a certain level, the flow is shut off.

Freestanding – Furniture or units that are not built-in or fixed to a wall or floor.


Galvanised – Covered with a protective coating of zinc.

Gasket – A ring made out of rubber that seals the junction between two surfaces, e.g. between a toilet cistern and pan on a close coupled toilet.

Grain – The direction of wood fibres in a particular work piece. Also a pattern on the surface of timber made by cutting through the fibres.

Groove – A long, narrow channel cut in plaster or wood. In the latter, this follows the direction of the grain.

Grounds – Strips of wood fixed to a wall to provide nail-fixing points for skirting boards, etc.


Header tank or Cold water storage tank – Normally found in the loft, it’s a tank for holding water that feeds into a home water system.

Heating element – Can be used with radiators or heated towel rails to provide a source of heat, independent to a central heating system.

High level cistern – Where the toilet cistern is mounted on the wall, high above the toilet and connected to the pan with a long flush pipe. Usually found on traditional style toilets with a pull chain flush.

Housing – A long, narrow channel cut across the general direction of wood grain to form part of a joint.


Insulation – Material used to reduce the transmission of heat or sound. Also a non-conductive material around electrical wires or connections to prevent the passage of electricity.

Isolating valve – A valve used to shut off water from a particular room or appliance, so you don’t need to turn off the entire water system.


Joist – A horizontal wooden or metal beam used to support a structure such as a floor, ceiling or wall.


Key – To roughen a surface to provide a better grip when it is being glued. Also the surface so roughened.

Knotting – Sealer, made from shellac, that prevents wood resin bleeding through a surface finish.

Knurled – On a knob or handle, a series of fine grooves impressed into an edge or surface to improve the grip when turned or handled.


Laminate – Two or more sheets of material bonded together, or the top waterproof sheet of the bonded sheets used as a work surface. Also to fix such sheets together.

Lintel – A horizontal beam used to support the wall over a door or window opening.

Lipping – A decorative strip applied to the side edges of laminated boards.

Low level cistern – Where the toilet cistern is mounted on the wall, a small distance above the toilet and connected to the pan with a short flush pipe. Usually found on traditional style toilets.

L-shaped shower bath – A shower bath with a wider, square-shaped end for showering. Looks like an “L” from overhead.


MDF – Medium-density fibreboard. A man-made sheet material that can be worked like wood and is used as a substitute for it.

Mitre – A joint between two pieces of wood formed by cutting 45⁰ bevels at the end of each piece. Also to cut such a joint.

Mixer tap – A single tap which combines the hot and cold water flows.

Modern - A style of interior decorating that contains elements that are clean and uncomplicated and draws upon popular design from the 1920s – 50s.

Monobloc tap – another name for a mixer tap.

Mounting frame – Sits behind a wall and is used to secure a wall hung toilet to a wall.


Noggin – Horizontal reinforcing timber fixed between the vertical studs in a stud partition wall.


Outlet – See Shower outlet.

Overflow pipe – A pipe leading from a tank or cistern used to drain off excess water into an area that won’t cause damage in the event of a malfunction.


Pan – The part of the toilet that is also referred to as the bowl.

Pedestal basin – A basin that is attached to the wall and sits on top of a pedestal, which is used to conceal plumbing. The pedestal extends all the way from the basin to the floor.

Pillar taps – Single taps which deliver either hot or cold water, but not both.

Pilot hole – A small diameter hole drilled to act as a guide for a screw thread.

Power shower – A shower that uses an electric pump to boost the flow of water.

Primer – A coat of paint applied to wood or metal to seal it and act as a first coat.

Profile – The outline or contour of an object.

P-shaped shower bath – A shower bath with a wider, curved end for showering. Looks like a “P” from overhead.

PTFE – Tape made from polytetrafluorethylene, used to seal threaded plumbing fittings.

Pushfit connector – A plumbing connection that is simply pushed onto the pipes e.g. for connecting the toilet pan to the waste pipe.


Rebate – A stepped rectangular recess along the edge of a work piece, usually forming part of a joint. Also to cut such a recess.

Reveal – The vertical side of an opening.

Rising main or Riser – A pipe that supplies water under mains pressure, usually to a roof storage tank.

Roll top bath – A type of freestanding bath, usually with a rolled lip around the rim of the bath to help when getting in and out.


Score – To scratch a line with a pointed tool.

Scribe – To copy the profile of a surface on the edge of sheet material to be butted against it. Also to mark a line with a pointed tool.

Semi pedestal basin – A basin that is attached to the wall and sits on top of a short pedestal that is also attached to the wall and used to conceal plumbing. The pedestal does not extend all the way to the floor.

Semi recessed basin – A basin designed to fit into, but also overhang, a furniture unit.

Single ended bath – A bath where the tap(s) are situated at one end.

Shower bath – A multifunctional bath which can also be used with a shower. Specifically designed shower baths have a wider end in which to shower and come with a bath screen.

Shower outlet – Connects a shower hose to water pipes.

Shower slider rail kit – A shower where the height and position can be adjusted on a rail fixed to the wall.

Shut off valve – Used to isolate the cold water feed into a toilet in case of any issues.

Silicone mastic – A non-setting compound used to seal joints.

Slotted waste – For use with basins that have an overflow hole.

Soil pipe – A pipe that drains waste (water and sewage) from your toilet, basin or bath.

Soil stack – A vertical pipe that carries waste water from a property down into the sewer system.

Stack vent - A vent pipe that (on modern properties) extends to above roof height, to vent gases from the soil stack.

Stopcock – A form of ball valve used to control the flow of a liquid or gas e.g. your water mains.

Stud partition – A timber frame interior dividing wall.


Template – A cut-out pattern, made from paper, wood, metal etc, used to help shape a work piece accurately.

Thermoplastic — A tough plastic used in the construction of toilet seats. Remains warm to the touch.

Thermostatic mixer valve – Usually found on showers, this valve mixes hot and cold water to maintain a constant temperature.

Thermostatic radiator valve – A radiator valve that opens and closes automatically to maintain a set temperature.

Traditional – A style of interior decorating that contains classic, timeless elements, particularly from the Victorian and Edwardian periods.

Trap – A bent section of pipe (below a bath, basin, etc) containing standing water to prevent smells from escaping back into a property.

TÜV - "Technischer Überwachungsverein" (English: Technical Inspection Association) are German businesses that provide product inspection and certification. If you see "TÜV approved" on a product, it has been tested and certified for use. Equivalent bodies in the UK include the WRAS (see below).


U-bend – A type of trap shaped like a U.

Undercoat – A layer or layers of paint used to cover primer and build up a protective layer before a top coat is applied.

Unslotted waste – For use with basins that have no overflow hole.


Vanity unit – A furniture unit that contains storage and a basin. It can be floor mounted or wall hung.


Walk in shower enclosure – A shower enclosure without a door, but with a cleverly arranged set of panels to keep water in.

Wall hung toilet – A toilet that is attached to a mounting frame behind a wall or unit, so the cistern is concealed and the pan is suspended above the floor.

Wall hung basin – A basin that is attached to the wall, but has no pedestal.

Waste – Connects a basin, bath or shower tray with a trap, allowing waste water to flow into the waste pipe. Can contain a plug hole and plug.

Wetroom – A waterproofed (“tanked”) room, normally designed with a drain and slight slope to the floor. Wetrooms often feature an open shower without the need for a shower tray.

WRAS - The Water Regulations Advisory Scheme provides an approval scheme for a range of bathroom products, to ensure they use water efficiently and comply with Water Fittings Regulations.

Read our bathroom jargon buster?

For a more in-depth look at some of these terms, why not check out our bathroom jargon buster?


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