Common terms used


Anti lift Device:
A device fitted over an opening sash in-between the sash and frame profile, usually fitted on sliding patios or double doors

Annealed Glass:
Ordinary glass, not safety glass (has had some treatment).

Lengths of timber or PVC-U used to build surrounds on the inside of a door or window.

Astragal Georgian Bars:
Georgian bars (usually white) which sit on the outside pane and the inside pane and also have a spacer bar in the double glazed unit. These have the appearance of separate panes and so look more authentic than Georgian inserts, but are harder to clean and more difficult to manufacture, hence more expensive (also known as cottage bars).

Fascia board in wood or pvc-u which is vertical and usually on the gable of a house.

Bay window:
A composite of three or more windows, usually made up of a large center unit and two flanking units at 30- or 45-degree angles to the wall. Can also be a 90 degree bay.

Bow window:
A composite of four or more window units in a radial or bow formation.

The section designed to secure the double glazed unit in place.

Butt Hinge:
These only tend to be used on windows when remote operating gear is installed. Unlike friction stays, they allow the sash to pivot at a fixed point. (Also used on doors).

Casement Window:
Traditional outward opening window.

Cill (Sill):
A window will normally have two sills, one internally (window board) and one external. The function of the external sill is to disperse water that has run down a window, preventing ingress beneath the window.

Boarding in wood or pvc-u which is sometimes used on outside of certain houses.

Claw bolt:
A type of deadbolt having claws which swing out sideways when the bolt is shot. Such locks are usually fixed to sliding doors.

Claw locks (see hinge protector):
Used at the hinge side of a casement window to give extra security.

Cottage Bars:
See Astragal Georgian bars

A unit of sound measurement.

A single bolt mortise lock which can be used to supplement a standard cylinder rim lock on the front door.

A hygroscopic substance used as a drying agent in insulating glass units.

A calculated temperature at which water vapour will condense.

Direct Fix:
This is where the metal window frame is secured direct to the wall/brickwork. The alternative is the metal frame is housed in a timber frame then fixed to the wall/brick work (frame fix).

Document "L":
Building regulations valid from 1 April 2002, designed to improve the environmental effects of window installations, particularly with regard to thermal efficiency. All new and replacement windows must comply, except in listed buildings.

A space which protrudes from the roof of a house, usually including one or more windows.

Dummy Vent:
A fixed window that has the same profile as an opening sash and hence produces "equal sightlines".

Equal sight line:
The profile on the fixed sections has additional bead (or thicker bead) to make the fixed window look identical to the opening window

Externally glazed/beaded :
This is where the glazing units (glass) are inserted from the outside, which is less secure unless special tapes or clips are fitted (this is then covered by decorative beads).

(Espag) A device which is fitted to the sash and operated via the handle, it moves mushroom cams, roller cams or shoot/hook bolts into strikers or keeps.

A top hung casement window, often but not necessarily, above a fixed pane.

The vertical board , wood or pvc-u, where the guttering is fixed to.

An architectural term referring to the arrangement of windows in a wall. From the Latin word, "fenestra", meaning window. Fixed Non-venting or non-operable.

Fenestration Self Assessment Scheme. An organization set up in 2002 to ensure window installers meet the new Document "L" regulations.

Fixed unit/Fixed light :
a non-opening window (i.e. fixed shut).

Fire Hinge (fire egress):
A hinge on a window that opens 90 degrees, to allow an easier emergency escape route than a standard scissors friction hinge.

Flag Hinge:
A type of door hinge that is surface mounted. Most offer horizontal and vertical adjustment.

Frame Fixings:
A device for fixing the frame of any type, door or window to the fabric of the building.

Friction stay hinge:
A variable geometry hinge which allows the sash to swing into the open position. An adjustable friction slide is built in to hold the sash in the open position. Various types are available, egress versions allow the sash to be fully opened so that it can be used as an emergency exit. Easy clean options allow the exterior to be cleaned when the sash is fully opened. As mentioned previously some incorporate a built in restrictor. Security versions are available.

A screw (various types for different applications), for fixing hardware to the frame sash

French Doors
Double opening doors which open out or in on butt hinges.

Georgian Bar (Georgian inserts):
A grid, normally white plastic or aluminium, that sits between the 2 panes of glass in the double glazed unit. Designed to look like a traditional Georgian window (but easier to clean). See also astragal Georgian bars.

Glazing Gasket:
Normally rubber, the gasket sits between the glass and any uPVC or aluminium components.

Glazing Packers:
Plastic packers which the glass sits on to allow water to pass beneath.

Glazing Beads:
A part of a window or door to locate and hold the glass or panel in position - can be internal or external.

The top of a window or door.

This operates the locking device to secure the window via the Espagnolette. Locking and non-locking types are available. On older types of window a cockspur handle may be fitted, this relies on a nib, which moves onto a transome locking the sash into the frame when the handle is operated. Handles are also the lock operating device on doors.

Hinge Bolt:
See hinge protector.

Hinge Protector (see claw locks):
Sometimes called a dog bolt or hinge bolt. Fitted to the hinge side of a door or window to enhance its security. It consists of a two piece device, based on a plate with a hole in. This is fitted onto the frame in the fittings cavity on the hinge side and a plate with a pin, which is fitted to the sash. When the sash is closed, the pin on the sash locates into the receiver plate mounted on the frame, so locking the sash into the frame.

Internally glazed/beaded:
This is the slightly more expensive approach where the glazing units (glass) are fitted from the inside.

The vertical component of a doorframe.

A brand name product (Pilkington "K") referring to a type of insulated glass designed to allow heat in but not out. It has a thin metallic film on the inside wall of the inner double glazed unit.

Laminated Glass:
Consists of two or more panels of glass attached to and separated from each other by means of an interlayer material used as safety/security glass. A laminate film can be applied to a single piece of glass.

Lead Designs:
Normally fitted to both sides of the external pane of the double glazed unit, available in a variety of designs.

Lever handle door furniture:
For use as an alternative to a knob for operating the latch of a lock. Lever handles can be springloaded or non-springloaded. Springloading ensures the handle returns to the horizontal position after use. Non-springloaded handles rely on the springing in the lock.

A concrete or metal beam used to bridge the gap above a window or door opening to bear the weight of the walls above.

Low "E" glass
Low emissivity glass, see also K-glass. Must be used to comply with Document "L".

Making good:
Ensuring that any gaps and holes created by the replacement work is tidied up.

Mortice lock:
A lock designed to be recessed into the edge of a door, rather than being mounted to its surface.

The vertical sections of a window between glazed areas.

Multipoint Locking System:
A lock with more than one locking point utilising bolts, shootbolts and/or hookbolts. Many versions and variations are available.

Mushroom driver:
A driver in the cylinder mechanism which has a mushroom shaped head. These provide a very effective anti-pick element against being lifted by a lock-pick or similar.

Night Vent:
A feature of pvc-u or aluminium casement windows whereby the sash can be locked in a slightly open position for ventilation.

One-way screws (or clutch head screws):
Screws with specially shaped heads to prevent removal by conventional screwdrivers.

A framed sheet of glass within a window.

Patio Door:
A sliding door where one or two parts slide to the side to provide the opening space.

Plant on Bay:
A bay or bow window which has been built where there used to be a flat window.

The window frame itself, the outer material (pvc/timber/metal).

Poly vinyl chloride - unplasticised. The material from which pvc-u windows are made.

The stepped shaped reduction or recess cut along the meeting edges of each of a pair of swing doors leaving projections which overlap when the two doors stop on each other at closing

Can be galvanised steel or aluminium. Designed to give rigidity, and is fitted inside the uPVC sections of a window or door.

The use of sand and cement plaster to form an exterior finish.

Residential Door:
A hinged door designed for residential use as opposed to commercial use.

The sections of a wall that return to the window frame.

Restrictor Device:
These are designed to restrict the amount that the sash will open (usually 100mm). They are often described as child restrictors ( In truth they should be only considered toddler proof). Various types are available, some are concealed in the fittings cavity others can be mounted directly on the outer frame/sash. Friction stay hinges can also incorporate a restrictor.

The opening section of a window

A chemical compound used as a weathertight joint between the window/door and the building.

Secondary Double Glazing
Glazing that fits inside of the outer windows. Typically used for noise reduction when original windows do not need to be replaced, can be vertically balanced with springs in the case of a sliding window.

Shoot Bolts:
A locking system for casement windows used to add security.

Side Light (Side Panel):
A glazed section to one or both sides of a door.

Sill (or cill):
A window will normally have two sills, one internally (window board) and one external. The function of the external sill is to disperse water that has run down a window, preventing ingress beneath the window.

The snib is the mechanism by which the door bolt can be held back, (put ‘on the latch'). It can either be a button with slide movement, or a push movement.

The horizontal board, wood, pvc-u or asbestos that goes under a fascia or bargeboard.

The part of the door handle usually of square section which passes through the top hole follower in a mortice door lock to operate the springbolt.

The procedure of measuring and detailing a job for pricing or manufacture.

Tempered glass:
Glass manufactured to withstand greater than normal forces on its surface. When it breaks, it shatters into small pieces to reduce hazard (see toughened glass).

Thermal break:
Fitted to aluminium windows and doors to prevent condensation by reducing "temperature transfer", from the outside to the inside.

A small fitting on the cylinder found on the inside of a door which is gripped between thumb and finger to operate the deadbolt. Should not be used on glass or wood-panelled doors. Ideal for fire exit doors where escape is always needed.

Trickle vent:
Ventilation devises normally fixed near the top of a window to allow air to flow when a window is securely locked. These are compulsory in new properties.

The horizontal components of a window between glazed sections.

Tilt and Turn window:
Window that has two opening positions, one tilting inwards for ventilation, the other opening inwards as a door for cleaning or escaping.

Toeing and heeling:
A system of packing glass or panel unit within the window/door to prevent the opening sash dropping.

Toughened Glass:
Sometimes call tempered glass, produced by a special heating process applied to ordinary float glass, producing a safety glass.

Topswing / Sideswing or Fully Reversible Hinge:
This type of hinge allows the sash to be turned so that the glass can be cleaned from the inside without having to lean out of the window. A two-position restrictor is built in as standard, the first acts as a stop to allow the sash to be opened 100mm, the second permits the sash to be released and fully reversed for cleaning. This type of hinge is concealed in the fittings cavity.

Horizontal member separating one window pane from another.

Rate of heat flow-value through the complete heat barrier, from room air to outside air. The lower the U-value, the better the insulating value.

Unequal sight line:
The opening section of the window has a smaller pane of glass than fixed window so the profile (frame) is thicker, this gives the appearance of a smaller window more noticeable if leaded decoration is used.

The opening section of a window.

Vertical Sliding window:
Traditional boxed sash window.

Weather seal:
Normally rubber, provides a watertight seal between a sash and frame.

Wedge Gasket:
See glazing gasket. The wedge is only used internally on externally glazed windows, and prevents the glazing beads being removed from the outside by burglars.

Window Board:
The internal window cill, usually made from timber but sometimes pvc-u.

White Woodgrain finish:
A new white foil finish on pvc-u windows to give the appearance of painted wood.

Woodgrain finish:
A foil finish on pvc-u windows to give the appearance of mahogany wood.

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