Aluminium Fabrication Glossary

A matched family of aluminium profiles, gaskets, beads and hardware designed and tested to work together — for example a door suite or a window suite. A fabricator works within a system; they do not mix profiles from different suites on the same unit.

We fabricate on the Jack Aluminium platform and compatible profiles, so the hardware and seals are matched, not improvised.

Jack Aluminium compatibility for installers →

A length of aluminium pushed through a shaped die to form a constant cross-section — the raw stock a fabricator cuts and machines into frames. Each profile in a suite has a defined cross-section, wall thickness and chamber arrangement.

A profile split into inner and outer aluminium sections joined by a low-conductivity insulating bar, so heat cannot pass straight through the metal. Thermally broken frames are required on virtually any external door or window in a heated building to meet thermal targets.

Our thermally broken entrance doors and windows are built for Part L work.

Thermally broken entrance doors →

The specific insulating bar — usually glass-reinforced polyamide (nylon) — crimped between the inner and outer aluminium shells to form the thermal break. Polyamide is the standard material because it is strong, dimensionally stable and a poor conductor of heat.

The visible width of aluminium framing seen face-on once the unit is glazed — the slimmer the sightline, the more glass and the cleaner the look. Slim-sightline frames are prized on shopfronts and heritage work but are less forgiving of fabrication error.

Heritage doors use slim sightlines to suit listed and conservation frontages.

Heritage doors →

A vertical structural member dividing a frame, curtain wall or screen into bays. Mullions carry wind load and locate the glazing or infill on either side.

A horizontal member spanning between mullions or jambs — for example the bar separating a door leaf from the fanlight above it. Transom and mullion alignment is one of the first things a fabricator verifies on coordinated frontages.

The fixed perimeter frame that is mechanically fixed into the building opening; the door leaf or window sash hangs within it. On replacement work the building opening — not the original drawing — is the true datum for the outerframe.

The opening part of the unit. "Sash" or "vent" is the moving part of a window; "leaf" is the moving part of a door. Each is measured and built to operate within its outerframe.

The bottom horizontal member of a frame, often with a weathered or stepped profile to shed water clear of the wall below. The right cill depth depends on the reveal and the wall build-up, which is why it is a survey field worth capturing.

The stepped recess in a frame that receives the door leaf, sash or glazing and houses the weatherseal. A threshold or bead sitting proud of its rebate is a classic source of a leaf that will not close cleanly.

A profile or sleeve used to join two frames together side-by-side or stacked — for example coupling a window to a door frame to form a screen. Couplings must be specified at quote stage so the combined unit is engineered and labelled as one assembly.

The standard factory finish for architectural aluminium: polyester powder is electrostatically applied and oven-cured to a durable, colour-fast coating. Polyester powder coating (PPC) is specified by colour reference and finish — matt, satin, gloss or textured.

The European colour-matching standard used to specify powder-coat finishes — e.g. RAL 7016 Anthracite Grey or RAL 9005 Jet Black. Always quote the RAL number and finish; "grey" alone is not orderable.

A frame powder-coated one colour externally and a different colour internally — common where a building exterior must match a palette but the interior wants white or a neutral. Dual-colour adds a coating operation, so flag it at quote stage as it affects lead time.

A quality-assurance standard and licensing scheme for the powder-coating of architectural aluminium, setting requirements for pre-treatment, coating and testing. Specifying a Qualicoat-approved coater is the way to evidence finish durability and support a coating warranty rather than relying on the colour reference alone.

Two or more panes of glass separated by a spacer and hermetically sealed at the edge to trap an insulating gas cavity. The build-up — pane thicknesses, cavity width, coatings — determines the glazing contribution to the U-value and acoustic performance.

The removable profile that clips in to retain the glass or infill panel in its pocket. Internally beaded units are more secure because the bead cannot be removed from outside; on factory-glazed leaves we check bead security as part of pre-dispatch testing.

A glazing method where glass is bonded or retained so the framing is concealed or minimal, giving a flush external glass face. Structural and capped glazing are curtain-wall techniques that demand tight fabrication tolerances.

A solid panel — insulated, aluminium-faced or decorative — used in place of glass within a frame or curtain wall bay, for example below a transom or at a spandrel zone. Specified by thickness and U-value to coordinate with the glazing pocket.

The opaque zone of a façade between the head of one floor’s glazing and the cill of the next, concealing the floor slab and services. Spandrel zones are typically formed with an insulated infill panel or back-painted glass.

Glass heat-treated to be far stronger than annealed glass and, when broken, to shatter into small blunt granules — a safety glass under the relevant standard. Specified where impact safety or thermal stress demands it.

Two or more panes bonded with an interlayer so that, when broken, fragments are held in place — giving safety, security and acoustic benefits. Security-rated and many overhead applications call for laminated glass specifically.

Laminated glass made with a specialist acoustic interlayer that damps sound transmission, used where a unit faces a busy road, railway or other noise source. It is specified by its sound-reduction rating in decibels (dB), so capture the target figure rather than asking simply for "acoustic glass".

A low-conductivity spacer bar around the perimeter of a sealed unit that reduces heat loss and condensation risk at the glass edge compared with a traditional aluminium spacer. It improves the whole-unit U-value and is widely specified on Part L work.

The three U-values that make up a window figure: Ug is centre-of-glass, Uf is the frame, and Uw is the whole window combining both with the spacer effect. A quote that states only Ug is incomplete — compliance is judged on Uw or the whole-doorset value.

A locking mechanism that engages at several points up the leaf edge from a single key or handle throw, spreading the holding force and improving security and weather seal. Standard on residential and light-commercial entrance doors and part of the PAS 24 tested assembly.

A closing device set into the floor beneath a pivoting door, controlling both the closing speed and the hold-open of heavy commercial leaves. Specified by leaf weight and width, and verified through full operating cycles before dispatch.

We cycle floor-spring and pivot operation on the jig before our commercial doors ship.

Commercial entrance doors →

A door hung on a top and bottom pivot point rather than side hinges, allowing heavier leaves and wider openings — typical of high-traffic commercial entrances. Pivot capacity is rated by weight, so the glass build-up has to be checked against it.

A door arrangement, usually on sliding or pivoting entrances, that allows the leaves to swing out to a full clear opening for emergency egress. A life-safety feature on automatic and public-entrance doors that must be specified, not assumed.

The provision for getting out of a building in an emergency — for example breakout leaves on an automatic or sliding entrance that open to a clear escape route. Egress is a distinct requirement from everyday operation, so a door’s escape arrangement has to be specified in its own right and not assumed from the way it normally opens.

A hinge-side detail — a flexible cover or shaped profile — that closes the gap where fingers could be trapped between leaf and frame. Routinely required on doors in schools, nurseries, healthcare and other public buildings.

A device, surface-mounted or concealed in the transom, that controls the closing of a door and ensures it latches. Closer power size must suit the leaf and the draught conditions, or the door will either slam or fail to close.

The bottom member of a doorway the leaf closes onto — ranging from a low or level-access threshold for accessibility to a weathered or drained threshold for exposed external doors. Threshold type is a key survey and schedule field because it affects both weather performance and access compliance.

A low or flush threshold that gives step-free entry to meet the accessibility requirements of Approved Document M. Because a flatter threshold has less upstand to hold back wind-driven water, it is a trade-off against weather performance — so the threshold type, drainage and exposure all need confirming on the schedule.

The standardised replaceable lock cylinder used in most multipoint locks, available in security grades and anti-snap specifications. Because the cylinder is part of a security-tested doorset, swapping it for a lower grade can invalidate the PAS 24 evidence.

A device limiting how far a window or door can open, for safety (fall prevention) or controlled ventilation. Restricted openings must be set and checked as part of hardware function before the unit leaves the workshop.

The motor and control unit that drives an automatic sliding or swing door. Frame fabricators commonly supply the aluminium entrance frame ready for integration with a third-party operator rather than the drive itself.

We supply automatic-ready entrance frames for integration with third-party operators — frame only.

Automatic sliding doors →