Apparatus, System and Method for Retaining and Aligning Adjacent Panels

Abstract

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Description

RELATED APPLICATIONS This applica*on claims priority from Australia patent applica*on number 2025904058 filed on 3 5 September 2025, the contents of which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to apparatuses, systems and methods for retaining and aligning adjacent panels and, more par*cularly, to temporary and releasable reten*on and alignment of 10 panels on a substrate during adhesive curing. BACKGROUND Stone facade panels are widely used in architectural cladding for walls, roofs and other building surfaces. Such panels may be fabricated from natural or engineered stone to provide a durable 15 and visually consistent exterior finish. Panels are commonly secured to an underlying substrate using construction-grade adhesive, with an installation objective of providing a substantially flush exterior surface while maintaining suitable spacing between adjacent panels. However, adhesive-based panel installation can be affected by variations in panel thickness, surface flatness, support positioning, substrate flatness and adhesive cure time. During the 20 period before an adhesive has developed sufficient bond strength, panels may remain susceptible to localised movement, protrusion, recession or loss of alignment relative to adjacent panels. These issues can be more pronounced in facade, overhead, soffit or large-format panel installations, where panel weight and access constraints may complicate manual adjustment. 25 Known installation techniques include manual clamps, tile levelling spacers, clip-on brackets, suction or magnetic retainers, shims, packers and proprietary fixing arrangements. Published patent literature also describes exterior wall finishing material fixing devices in which a wallmounted connection arrangement supports an installation member, exterior finishing material is bonded using silicone, and a temporary restraining member is used to hold the bonded parts 30 while the silicone hardens. 2026226403   02 Sep 2026 However, established approaches can involve bulky or bespoke fixtures, reliance on panel surface conditions, repeated manual adjustment, limited retention against out-of-plane movement, or fixing arrangements that are directed primarily to mounting support rather than repeatable flush alignment of adjacent panel faces during adhesive curing. There remains a 5 need for a practical arrangement that can assist in temporarily retaining adjacent panels and maintaining alignment while adhesive cures, or at least provide the public with a useful choice. SUMMARY The present disclosure relates generally to retaining and aligning adjacent panels during curing. 10 Broad aspects of the disclosure relate to an apparatus, a system and a method in which an extrusion, an adhesive layer and a removable T-slot tool cooperate to urge exterior faces of adjacent panels into flush alignment while curing of the adhesive layer occurs. According to an aspect of the present disclosure, an apparatus for retaining and aligning adjacent panels during curing may comprise a substrate, a coupling system comprising an 15 extrusion fixed to the substrate, the extrusion having an exterior face, an adhesive layer applied to the exterior face of the extrusion, and at least two adjacent panels adhered to the adhesive layer, adjacent sides of the at least two adjacent panels defining a gap. The extrusion may define an elongated channel with an opening aligned with the gap between the adjacent panels. The elongated channel may have a generally U-shaped cross-section with a base and 20 two side walls, the two side walls having opposing inwardly projecting overhangs. The apparatus may further comprise a T-slot tool comprising a shaft, a bearing face, and a T-shaped end formed at one end of the shaft. The T-shaped end may comprise a crossbar portion projecting laterally from the shaft, the crossbar portion having a width greater than the opening in the elongated channel such that, in an engagement orientation, the crossbar 25 portion underlies the inwardly projecting overhangs. The T-shaped end may be insertable through the gap and into the opening in the elongated channel in an insertion orientation and may be rotatable within the elongated channel to an engagement orientation in which the T-shaped end is positioned under the inwardly projecting overhangs. The T-slot tool may be configured to draw the T-shaped end axially towards the bearing face to apply a compressive 30 force via the inwardly projecting overhangs on the adjacent sides of the at least two adjacent panels to urge their exterior faces into flush alignment while curing of the adhesive layer occurs. The T-slot tool may further comprise a threaded coupling between the shaft and the bearing face, the threaded coupling being configured to advance the bearing face axially along 2026226403   02 Sep 2026 the shaft upon rotation of the shaft relative to the bearing face, and the bearing face may comprise a plate extending transverse to the shaft. According to some embodiments, rotation of the T-shaped end from the insertion orientation to the engagement orientation may comprise rotation through an angle sufficient for the 5 crossbar portion to at least partially underlie both of the opposing inwardly projecting overhangs. According to some embodiments, the extrusion may be an aluminium extrusion, and the inwardly projecting overhangs may be formed as one piece with the aluminium extrusion. According to some embodiments, the inwardly projecting overhangs may project from 0.5 mm 10 to 5 mm into a volume of the elongated channel. According to another aspect of the present disclosure, a system for retaining and aligning panels on a substrate during adhesive curing may comprise a substrate, a coupling system comprising an extrusion fixed to the substrate, the extrusion having an exterior face, an adhesive layer applied to the exterior face of the extrusion, and at least two adjacent panels 15 adhered to the adhesive layer, adjacent sides of the at least two adjacent panels defining a gap. The extrusion may define an elongated channel with an opening aligned with the gap between the at least two adjacent panels. The elongated channel may have a generally U-shaped crosssection with a base and two side walls, the two side walls having opposing inwardly projecting overhangs projecting into a channel volume. The system may further comprise a T-slot tool 20 having a shaft and a bearing face, the tool comprising a T-shaped end formed at one end of the shaft. The T-shaped end may comprise a crossbar portion projecting laterally from the shaft, the crossbar portion having a width greater than the opening in the elongated channel such that, in an engagement orientation, the crossbar portion underlies the inwardly projecting overhangs. The T-shaped end may be insertable through the gap and into the opening of the 25 elongated channel, and may be rotatable within the elongated channel from an insertion orientation, in which the T-shaped end aligns with the opening in the elongated channel, to an engagement orientation, in which the T-shaped end is positioned under the inwardly projecting overhangs. The tool may be configured to draw the T-shaped end axially towards the bearing face to apply a compressive force via the inwardly projecting overhangs on the adjacent sides 30 of the at least two adjacent panels, thereby urging the exterior faces of the at least two adjacent panels into flush alignment while curing of the adhesive layer occurs. The T-slot tool may further comprise a threaded coupling between the shaft and the bearing face, the threaded coupling being configured to advance the bearing face axially along the shaft upon 2026226403   02 Sep 2026 rotation of the shaft relative to the bearing face, and the bearing face may comprise a plate extending transverse to the shaft. In some embodiments, rotation of the T-shaped end from the insertion orientation to the engagement orientation may comprise rotation through an angle sufficient for the crossbar 5 portion to at least partially underlie both of the opposing inwardly projecting overhangs. In some embodiments, the extrusion may be an aluminium extrusion, and the inwardly projecting overhangs may be formed as one piece with the aluminium extrusion. In some embodiments, the inwardly projecting overhangs may project from 0.5 mm to 5 mm into the channel volume. 10 According to another aspect of the present disclosure, a method of retaining and aligning panels on a substrate during adhesive curing may comprise providing a substrate, fixing to the substrate an extrusion having an exterior face and defining an elongated channel with an opening in the exterior face, the opening aligned with a gap between sides of adjacent panels, the elongated channel having a generally U-shaped cross-section with a base and two side 15 walls, the two side walls having opposing inwardly projecting overhangs, applying an adhesive layer to the exterior face of the extrusion, and adhering at least two adjacent panels to the adhesive layer such that the sides of the adjacent panels define a gap aligned with the opening in the elongated channel. The method may further comprise inserting into the gap a T-slot tool comprising a shaft, a bearing face and a T-shaped end. The T-shaped end may comprise a 20 crossbar portion projecting laterally from the shaft, the crossbar portion having a width greater than the opening in the elongated channel such that, in an engagement orientation, the crossbar portion underlies the inwardly projecting overhangs. The T-slot tool may further comprise a threaded coupling between the shaft and the bearing face, the threaded coupling being configured to advance the bearing face axially along the shaft upon rotation of the shaft 25 relative to the bearing face, and the bearing face may comprise a plate extending transverse to the shaft. The T-shaped end may be introduced into the elongated channel in an insertion orientation in which the T-shaped end aligns with the opening in the elongated channel, rotated within the elongated channel to an engagement orientation in which the T-shaped end is positioned under the inwardly projecting overhangs, and drawn axially towards the bearing 30 face by rotation of the shaft so as to apply a compressive force via the inwardly projecting overhangs against the sides of the adjacent panels. The compressive force may be maintained whilst curing of the adhesive layer occurs, and the compressive force may be subsequently 2026226403   02 Sep 2026 loosened before rotating the T-shaped end back to the insertion orientation and removing the T-slot tool from the gap. In some embodiments, rotating the T-shaped end within the elongated channel may comprise rotating the T-shaped end through an angle sufficient for the crossbar portion to at least 5 partially underlie both of the opposing inwardly projecting overhangs. In some embodiments, the extrusion may be an aluminium extrusion, and the inwardly projecting overhangs may be formed as one piece with the aluminium extrusion. In some embodiments, the inwardly projecting overhangs may project from 0.5 mm to 5 mm into a channel volume. 10 In some embodiments, maintaining the compressive force may comprise retaining the T-slot tool in position during a predetermined adhesive curing period. By using the T-slot tool to engage the inwardly projec*ng overhangs of the elongated channel through the gap between adjacent panels, the apparatus, system and method may provide temporary reten*on and alignment during adhesive curing while allowing the T-slot tool to be 15 removed aSer curing. The disclosed arrangement thereby addresses issues associated with retaining and aligning adjacent adhesively mounted panels without requiring a permanent visible fastener at the gap. BRIEF DESCRIPTION OF THE DRAWINGS 20 Further aspects of the apparatus, system and method for retaining and aligning adjacent panels will become apparent from the following descrip*on that is given by way of example only and with reference to the accompanying drawings in which: Figure 1 illustrates a perspec*ve view of a wall assembly ready for stone panel placement having a substrate or a building paper or membrane and extrusions fixed to the substrate and 25 adhesive applied to the exterior faces of the extrusions; Figure 2 illustrates a perspec*ve view of the wall assembly with stone panels being adhered to the extrusions; Figure 3 illustrates a perspec*ve view of the wall assembly with stone panels adhered to the extrusions; 30    Figure 4 illustrates a detail cross-sec*onal view of the wall assembly of Figure 3 from above showing the adjacent stone panels, extrusions, coupling system and substrate; 2026226403   02 Sep 2026 Figure 5 illustrates the above wall assembly and stone panels with the tools fiWed and further comprising a ceiling structure or substrate; Figure 6 illustrates the above wall assembly and stone panels with the tools fiWed and with stone panels being adhered to extrusions on the ceiling structure or substrate; 5 Figure 7 illustrates the above wall assembly and stone panels with the tools fiWed and with stone panels adhered to extrusions on the ceiling structure or substrate; Figure 8 illustrates a detail cross-sec*on view of the T-slot tool being fiWed. A T-shaped end of a T-slot tool comprising a shaS, a bearing face and the T-shaped end is inserted into the gap. The T-shaped end has been introduced into the elongated channel in an inser*on orienta*on as 10 shown in which the T-shaped end aligns with the opening in the elongated channel; Figure 9 illustrates a detail cross-sec*on view of the T-slot tool fiWed, with the T-shaped end of the T-slot tool rotated to an engagement orienta*on in which the T-shaped end at least par*ally underlies the inwardly projec*ng overhangs of the elongated channel and is drawn against the inwardly projec*ng overhangs to impose a compressive force between the inwardly projec*ng 15 overhangs and the exterior faces of the adjacent sides of the stone panels; and Figure 10 illustrates the above wall and ceiling assembly with the stone panels and the tools fiWed and prior to removal of the tools post curing of the adhesive layers. DETAILED DESCRIPTION 20 As noted above, the description herein provides illustrative embodiments of an apparatus, system, and method for retaining and aligning adjacent panels, particularly stone facade panels, during adhesive curing. The described technology is presented in the context of architectural cladding applications, where precise alignment and retention of panels are necessary to achieve a flush exterior surface. While specific embodiments and examples are 25 provided to facilitate understanding, these are presented as examples only and are not intended to limit the scope of the described technology. For clarity and conciseness, certain well-understood principles, components, and techniques commonly u*lised in the field of panel installa*on and alignment may not be described in comprehensive detail. Furthermore, various modifica*ons, subs*tu*ons, and rearrangements 30 of the described elements and methods may be implemented without devia*ng from the scope defined by the claims. Consequently, the described subject maWer includes all such varia*ons that align with the intent and scope of the appended claims. 2026226403   02 Sep 2026 For the purposes of this specifica*on, the term ‘about’ or ‘approximately’ and gramma*cal varia*ons thereof mean a quan*ty, level, degree, value, number, frequency, percentage, dimension, size, amount, weight or length that varies by as much as 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1% to a reference quan*ty, level, degree, value, number, frequency, percentage, 5 dimension, size, amount, weight or length. As used herein, the term ‘substan*ally’ refers to a degree, extent, orienta*on, alignment or condi*on that need not be exact, but that is sufficiently close to the stated degree, extent, orienta*on, alignment or condi*on to perform the technical func*on or achieve the technical purpose described in the relevant context. For example, a substan*ally flush condi*on may 10 permit manufacturing, installa*on or material tolerances while s*ll presen*ng adjacent exterior panel faces as flush for the intended installa*on, and a substan*ally 90 degrees rota*on or angle may include ordinary angular tolerances while s*ll moving or posi*oning the relevant component in the manner described. The term 'comprise' and gramma*cal varia*ons thereof shall have an inclusive meaning - i.e. 15 that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. The term ‘retaining’ and gramma*cal varia*ons thereof refers to the act of holding or securing an object in a fixed posi*on or loca*on, oSen temporarily, to prevent movement or displacement. In the context of the inven*on, it involves maintaining adjacent panels in a stable 20 posi*on during adhesive curing to ensure proper alignment and posi*oning. Apparatus The following aspects describe the apparatus, system and method at a rela*vely broad level before par*cular components, variants and installa*on examples are described in more detail. 25 The features described in connec*on with one aspect may be used with another aspect where technically compa*ble, unless the context requires otherwise. According to one aspect of the present disclosure, an apparatus may be provided for temporarily retaining and aligning adjacent panels while an adhesive layer cures. The apparatus may include a substrate-mounted extrusion, an adhesive layer on an exterior face of the 30 extrusion, adjacent panels adhered to the adhesive layer, and a removable T-slot tool that is used during installation. The adjacent panels may define a gap that provides access to an 2026226403   02 Sep 2026 elongated channel of the extrusion, so that the T-slot tool can cooperate with internal reaction surfaces of the channel while remaining removable after curing. The extrusion may define the elongated channel with an opening aligned with the gap between the adjacent panels. Opposing inwardly projecting overhangs of the elongated channel may 5 provide reaction surfaces for a T-shaped end of the T-slot tool. In use, a crossbar portion of the T-shaped end may be inserted through the gap and into the channel in an insertion orientation, then rotated to an engagement orientation in which the crossbar portion underlies the inwardly projecting overhangs. Axial draw-up between the T-shaped end and a bearing face of the tool may then apply a temporary compressive force at the gap to urge exterior faces of the 10 adjacent panels towards flush alignment during curing of the adhesive layer. In some embodiments, the axial draw-up may be provided by a threaded coupling between a shaft of the tool and the bearing face, and the bearing face may comprise a plate extending transverse to the shaft. 15 System According to another aspect of the present disclosure, a system may be provided for installing panels on a substrate using the extrusion, adhesive layer and removable T-slot tool described herein. The system may be used across one or more panel joints, and may include one or more extrusions fixed to the substrate and one or more T-slot tools positioned through respective 20 gaps between adjacent panels. Each extrusion may present an elongated channel accessible through a corresponding gap, and each tool may be tightened temporarily to retain and align neighbouring panels while the adhesive layer cures. The system may be adapted for different installation environments, including walls, ceilings, soffits, overhangs, reveals, sills, signage, gates, fences and transitions between surfaces. The 25 substrate, panel material, adhesive layer, extrusion length, channel geometry, gap width and number of tools may be selected according to the installation region. In each case, the extrusion and adhesive layer may provide the permanent panel support after curing, while the T-slot tool may provide removable installation control during the curing period. 30 Method According to another aspect of the present disclosure, a method may be provided for retaining and aligning panels on a substrate during adhesive curing. The method may include fixing an 2026226403   02 Sep 2026 extrusion to the substrate, applying an adhesive layer to an exterior face of the extrusion, and positioning adjacent panels on the adhesive layer so that a gap between the adjacent panels is aligned with an opening into an elongated channel of the extrusion. A T-slot tool may then be introduced through the gap, with a T-shaped end of the tool passing into the elongated channel 5 in an insertion orientation. The T-shaped end may be rotated within the elongated channel to an engagement orientation in which the T-shaped end cooperates with inwardly projecting overhangs of the channel. The tool may then be tightened, for example by rotating a shaft relative to a bearing face through a threaded coupling, to draw the T-shaped end axially towards the bearing face and apply a 10 compressive force at the adjacent panel sides. The compressive force may be maintained while the adhesive layer cures, and after curing the tool may be loosened, rotated back towards the insertion orientation and removed from the gap. Particular features of the extrusion, channel, gap, tool, panels, adhesive layer and substrate will 15 now be described. These features may be used individually or in combination with the apparatus, system and method aspects described above, and may provide support for different installation arrangements within the general retaining and aligning function of the disclosure. Opening and Gap Alignment 20 The opening of the elongated channel in the extrusion may be substan*ally aligned with the gap between the at least two adjacent panels. The opening and gap may be an elongated slot shape. The elongated slot may be con*nuous from the top to the boWom of the adjacent panels. Con*nuous opening may not be essen*al and for example, discon*nuous openings may be used e.g. via spaced apart gaps in the 25 adjacent panel sides. Inwardly Projec<ng Overhangs The inwardly projecting overhangs may project 0.5 mm to 5 mm into a volume of the elongated channel. The inwardly projecting overhangs may project 0.5, or 1.0, or 1.5, or 2, or 2.5, or 3, or 30 3.5, or 4, or 4.5, or 5 mm into a volume of the elongated channel. This dimension refers to the distance a single inwardly projec*ng overhang projects into the volume of the elongated channel. 2026226403   02 Sep 2026 T-shaped End The T-shaped end may comprise a crossbar por*on projec*ng laterally from the shaS. The crossbar por*on may have a width greater than the opening in the elongated channel. In the 5 engagement orienta*on, the crossbar por*on may underlie the inwardly projec*ng overhangs. T-Slot Tool The T-slot tool may further comprise a threaded coupling between the shaS and the bearing face. The threaded coupling may be configured to advance the bearing face axially along the 10 shaS upon rota*on of the shaS rela*ve to the bearing face. The bearing face may comprise a plate extending transverse to the shaS. This plate may be circular, ellip*cal, or polygonal in shape. Rota<on 15 Rota*ng the T-shaped end of the tool within the elongated channel may comprise rota*ng the T-shaped end sufficiently for the T-shaped end to at least par*ally underlie the inwardly projec*ng overhangs of the elongated channel. In some embodiments, rota*on from the inser*on orienta*on to the engagement orienta*on may comprise rota*on through an angle in a range from 45 degrees to 90 degrees, from 50 degrees to 90 degrees, from 60 degrees to 90 20 degrees, from 70 degrees to 90 degrees, or from 80 degrees to 90 degrees. In some embodiments, rota*on from the inser*on orienta*on to the engagement orienta*on may comprise rota*on through substan*ally 90 degrees. Adjacent Panels 25 The adjacent panels may form a facade, cladding surface, lining surface or decora*ve surface. The term ‘facade’ as used herein refers to the frontage or face of a wall, ceiling, soffit, roof, reveal, head, sill or other building planar structure. Further, unless stated differently, a facade in the context of this specifica*on may be an internal feature e.g. an interior / internal wall of a building and / or an exterior / external feature such as an 30 external wall face. 2026226403   02 Sep 2026 The inventor has found that the coupling system and adjacent panels described herein may be useful for interior installa*ons, in part because the extrusions need not intrude far into the internal area of the building The coupling system and adjacent panels described herein may also be useful for internal walls 5 since there may be less need for air movement, (or at least a lower volume of air movement), needed between the stone *les and substrate than may be required for an external wall exposed to rain and moisture in general. Stone Tile 10 The adjacent panels may be stone *les. The stone *les may be large-format surfaces or panels. The term ‘large’ in this context refers to an oblong *le shape or sheet with a width and / or height of at least 0.5 m. Stone *les envisaged for use as adjacent panels in the arrangements described herein may vary in width from 1, or 1.5, or 2, or 2.5, or 3, or 3.5, or 4, or 4.5, or 5, or 5.5, or 6, or 6.5, or 7, or 7.5, or 8, or 8.5, or 9, or 9.5, or 10 m and may vary in height from 1, or 15    1.5, or 2, or 2.5, or 3, or 3.5 ,or 4, or 4.5, or 5, or 5.5, or 6, or 6.5, or 7, or 7.5, or 8, or 8.5, or 9, or 9.5, or 10 m. They may be generally larger sheets or panels and the term ‘*le’ as used herein may refer to this larger format of *le. Mul*ple stone *les may be used to create the final apparatus or system. Each extrusion may comprise at least two stone *les adhered to the extrusion. 20 The stone may be sintered stone. The stone may be a natural stone such as limestone, or bluestone. Many different stone facade products exist and the problem of how to mount such products is common to many if not all of these products. Stone is a useful facade product given the longevity of the material (50+ lifespan material), thermal proper*es and aesthe*cs. 25 Note that the term ‘stone’ as used herein is used for brevity. Stone *les may be subs*tuted for other materials with similar proper*es, examples including wood, plas*cs and composite materials. Use of the term stone should not be seen as limi*ng. Gap 30 The gap between the adjacent sides of the adjacent panels may allow for expansion and contrac*on of the adjacent panels rela*ve to the extrusions. Small in this context refers to a 2026226403   02 Sep 2026 gap of 0.5 to 10, or 1-8, or 2-8, or 3-6, or 3-5 mm in width. The gap as noted above, may also be used to receive a T-slot tool therethrough in the manner described. The gap between the adjacent sides may run con*nuously along a length of each extrusion and may be common to mul*ple adjacent panels adhered to the extrusions. 5 Adhesive Layer As noted above, an adhesive layer may be used to adhere the extrusion to the adjacent panels. The adhesive layer may adhere to only part of a rear facing or obscured face of each adjacent panel and to only part of the exterior face(s) of the extrusion(s). 10 The adhesive layer may extend as an elongated strip along a longitudinal axis of each exterior face of each extrusion. A single strip may adhere to part or all of an adjacent panel. Two strips of adhesive may be located on each extrusion located on either side of a width of each extrusion. Each strip of adhesive layer may adhere to a separate adjacent panel; mul*ple adjacent panels being used to 15 form an exterior panel surface. Adhesive layers may be placed on an extrusion once the extrusion is fastened to the substrate. Alterna*vely, adhesive layers may be located on an extrusion when delivered to a site and prior to installa*on. In this case, a removable backing may be located over the adhesive layer to avoid contamina*on of the adhesive layer prior to adjacent panel adhering. 20 The adhesive layer used may be a commercially available product with a curing *me dependent on the type of adhesive used. The adhesive bond longevity may be at least 10 years. The adhesive layer may be a chemical adhesive. The adhesive layer may have elastomeric proper*es to provide some resilience and allow for some movement. 25 Curing of the Adhesive Layer Curing refers to a *me period during which an adhesive may undergo a chemical reac*on to form a strong and permanent bond. Different adhesives may have varying curing *me periods. Environmental condi*ons such as temperature and humidity may also impact curing *me. Curing may generally be complete once the adhesive hardens. This may be associated with the 30 adhesive forming cross-linked polymer chains. 2026226403   02 Sep 2026 The *me for curing may be known to the installer based on prior experience or a *me known to be well in excess of typical curing *mes. This may be the predetermined adhesive curing period. The curing *me period may typically be from 1 minute to 24 hours. 5 Step Each of the inwardly projec*ng overhangs may be non-linear in shape. In one example, each of the inwardly projec*ng overhangs may comprise a step projec*ng from the respec*ve side wall into the volume of the elongated channel. The step may then taper in a 10 linear or non-linear way back to a face of the side wall. Coupling The extrusion may be fixed to the substrate by mechanical fasteners. The mechanical fasteners may extend through apertures provided in the base of the elongated channel. 15 Extrusions Each extrusion may have a uniform cross-sec*on shape. The elongated length of each extrusion may be adjusted to suit the substrate to which the adjacent panels are to be applied to. By way of example, longer extrusions may be used for tall 20 walls while shorter extrusions may be used about detail wall or overhang sec*ons, such as a bulkhead or varied angle ceiling or wall to ceiling transi*on. Each extrusion may be an extrusion with a uniform cross-sec*on shape of infinite length; cut to suit the substrate to which each extrusion is to be fastened to. The extrusion may be an aluminium extrusion although other materials may be used. 25 Aluminium may be useful due to the longevity of this material and the light weight of aluminium. The overall width of an extrusion may be 20-200, or 30-180, or 40-160, or 50-150, or 75-125, or approximately 50 mm. 2026226403   02 Sep 2026 Each extrusion may have flanged sides. A first face of the flanged sides may bear on the substrate. Fasteners as noted above, may pass through the flanged sides and into the substrate. 5 Aligning Aligning as noted may be to locate the exterior faces of the panels into a generally flush alignment. Substrate 10 The substrate referred to herein may be a building frontage or face. Examples of substrate to which the apparatus or system may be applied comprise: a wall, overhang, ceiling, soffit, roof, reveal, head, sill, door, gate, fence, signage, or other planar face or frontage. That is, the apparatus or system may not be limited to placement on a ver*cally orientated face and may be used on angled faces or even horizontal plane faces, such as a 15 ceiling or soffit. The substrate itself may be manufactured from *mber, steel, concrete or SIP panel(s). It is envisaged that the apparatus and system may be fastened to the substrate e.g. framing, in a building structure. No wall lining may be needed. The extrusions may be directly fastened to the substrate, and it 20 may not be necessary to apply intermediate layers such as a wall lining, separate baWens, or spacer members between the substrate and the extrusions. The substrate may be a planar wall or a ceiling or soffit. The substrate may be a transi*on from one planar wall face to another planar wall face, each wall face at a different orienta*on to one another e.g. a 90 degree transi*on. For example, the 25 substrate may be an external or internal corner transi*on. The substrate may be a wall to ceiling or soffit transi*on e.g. from a ver*cally orientated planar wall to a horizontally orientated (or near horizontal orienta*on) planar ceiling or soffit. The substrate may also traverse transi*ons between ceiling sec*ons, soffit sec*ons and ceiling to soffit transi*ons. 30 2026226403   02 Sep 2026 Worked Installa<on Example The preceding subsec*ons iden*fy par*cular supported components, dimensions, materials and installa*on environments. The following worked installa*on example describes how those components may cooperate during installa*on and adhesive curing, without limi*ng the 5 broader apparatus, system and method aspects described above. In a worked installation example, a substrate is provided at a location at which adjacent panels are to be retained and aligned during curing of an adhesive layer. A coupling system comprising one or more extrusions is fixed to the substrate, each extrusion having an exterior face directed outwardly from the substrate. Each extrusion defines an elongated channel with an opening in 10 the exterior face. The elongated channel has a generally U-shaped cross-section with a base and two side walls, the two side walls having opposing inwardly projecting overhangs that project into a channel volume. In the illustrated form, the extrusion may be fixed to the substrate by mechanical fasteners, optionally through a coupling fixing, although other fixing arrangements suitable for securing the extrusion to the substrate may be used. 15 After the extrusion has been fixed to the substrate, the adhesive layer is applied to the exterior face of the extrusion. The adhesive layer may be applied as one or more lines along the exterior face, or may be applied as tape, spots, dashes or another discontinuous or continuous pattern. At least two adjacent panels are then adhered to the adhesive layer such that adjacent sides of the at least two adjacent panels define a gap. The panels are positioned so that the gap is 20 aligned with the opening in the elongated channel. In this condition, the opening provides access through the gap into the channel volume while the adhesive layer remains able to cure between the adjacent panels and the extrusion. A T-slot tool is then inserted into the gap. The T-slot tool comprises a shaft, a bearing face, and a T-shaped end formed at one end of the shaft. The T-shaped end comprises a crossbar portion 25 projecting laterally from the shaft and having a width greater than the opening in the elongated channel. During insertion, the T-shaped end is arranged in an insertion orientation in which the T-shaped end aligns with the opening in the elongated channel, so that the T-shaped end can pass through the gap and into the channel volume without bearing against the opposing inwardly projecting overhangs. 30 Once the T-shaped end is within the elongated channel, the T-shaped end is rotated within the elongated channel to an engagement orientation. In the engagement orientation, the T-shaped end is positioned under the inwardly projecting overhangs and the crossbar portion at least partially underlies the opposing inwardly projecting overhangs. In some embodiments, rotation 2026226403   02 Sep 2026 from the insertion orientation to the engagement orientation comprises rotation sufficient to move the crossbar portion from an orientation aligned with the opening to an engagement orientation in which the crossbar portion at least partially underlies the opposing inwardly projecting overhangs. In some embodiments, the rotation is in a range from 45 degrees to 90 5 degrees, from 50 degrees to 90 degrees, from 60 degrees to 90 degrees, from 70 degrees to 90 degrees, or from 80 degrees to 90 degrees. In other embodiments, the rotation is substantially 90 degrees. With the T-shaped end in the engagement orientation, the T-slot tool is operated to draw the T-shaped end axially towards the bearing face. The T-slot tool comprises a threaded coupling 10 between the shaft and the bearing face, the threaded coupling being configured to advance the bearing face axially along the shaft upon rotation of the shaft relative to the bearing face. The bearing face comprises a plate extending transverse to the shaft. Rotation of the shaft relative to the bearing face causes the bearing face and the T-shaped end to move towards one another, thereby applying a compressive force via the inwardly projecting overhangs on the 15 adjacent sides of the at least two adjacent panels. The compressive force urges exterior faces of the adjacent panels into flush alignment while curing of the adhesive layer occurs. The bearing face bears externally against the adjacent panels around the gap, while the T-shaped end reacts against the inwardly projecting overhangs within the elongated channel. The force path thereby extends from the bearing face, 20 through the adjacent panels and the inwardly projecting overhangs, to the T-shaped end and shaft of the T-slot tool. In this manner, the adjacent panels can be temporarily retained and aligned relative to the substrate while the adhesive layer develops sufficient bond strength. The compressive force is maintained whilst curing of the adhesive layer occurs. In some embodiments, maintaining the compressive force comprises retaining the T-slot tool in posi*on 25 during a predetermined adhesive curing period. Mul*ple T-slot tools may be used along a gap, or along respec*ve gaps between mul*ple adjacent panels, so that the exterior faces of the adjacent panels are held in flush alignment during curing across a broader installa*on area. ASer curing, the compressive force is loosened, the T-shaped end is rotated back to the inser*on orienta*on, and the T-slot tool is removed from the gap. The gap can then remain 30 between the adjacent sides of the panels without the T-slot tool being leS in place. Force Path and Panel Alignment 2026226403   02 Sep 2026 The clamping mechanics of the worked installa*on example will now be described in further detail. In par*cular, the following discussion explains how axial draw-up of the T-shaped end towards the bearing face can provide both temporary reten*on of the adjacent panels and alignment of their exterior faces while the adhesive layer cures. 5   When the T-shaped end is in the engagement orientation, axial draw-up of the T-shaped end towards the bearing face converts rotation of the shaft into a clamping action across the gap between adjacent panels. The threaded coupling permits the installer to progressively reduce the axial spacing between the bearing face and the T-shaped end, rather than relying on a fixed clip or a single-position spacer. As the bearing face engages exterior regions of the adjacent 10 panels and the T-shaped end reacts against the inwardly projecting overhangs, the applied load is transferred through the panels and the extrusion. This arrangement allows the same tool to both retain the panels against movement away from the extrusion and urge the adjacent exterior panel faces towards a substantially flush condition. The inwardly projecting overhangs provide reaction surfaces within the elongated channel for 15 the crossbar portion of the T-shaped end. Because the crossbar portion has a width greater than the opening of the elongated channel when in the engagement orientation, the T-shaped end is resisted from being withdrawn through the opening while the compressive force is applied. The overhangs accordingly cooperate with the T-shaped end to establish a releasable internal anchor point within the extrusion. This allows the compressive force to be applied 20 through the gap between the adjacent panels without requiring a permanent fastener, bracket or visible fixing to remain on the exterior panel faces after curing. The bearing face distributes the applied load over an exterior region of the adjacent panels around the gap. In embodiments in which the bearing face comprises a plate extending transverse to the shaft, the plate can bear against both adjacent panels so that tightening of 25 the threaded coupling tends to reduce relative protrusion or recession between the adjacent exterior faces. The resulting alignment force is applied at the interface between neighbouring panels while the adhesive layer remains uncured or partially cured, thereby assisting the panels to remain in a selected flush alignment until the adhesive layer develops sufficient bond strength. 30 Retention and alignment may occur together, but they perform different functions. Retention resists separation or displacement of the panels relative to the extrusion while the adhesive layer cures. Alignment urges the exterior faces of the adjacent panels towards a common plane, or towards a selected relative position, by applying compressive force locally at the gap. 2026226403   02 Sep 2026 The threaded coupling allows the magnitude of this compressive force to be adjusted during installation to accommodate tolerances in panel thickness, adhesive thickness, extrusion position and substrate flatness. ASer the predetermined adhesive curing period, the compressive force can be released by 5   loosening the threaded coupling. The T-shaped end may then be rotated from the engagement orienta*on back towards the inser*on orienta*on and withdrawn through the opening and the gap. The force path is accordingly temporary and reversible: during curing, the tool reacts against the extrusion and bears against the panels to assist reten*on and flush alignment; aSer curing, the tool may be removed so that the adhesive layer and extrusion con*nue to support 10 the panels without the tool remaining in place. Tool and Channel Variants The elongated channel may be configured to suit the substrate, the adjacent panels and the intended installation region while retaining an opening aligned with the gap between the 15 adjacent panels. In some embodiments, the opening and the gap may each be an elongated slot shape. The elongated slot may be continuous along a length of the adjacent panels, or may be discontinuous, for example where spaced apart gaps are provided between adjacent panel sides. In each case, the opening provides access from the gap into the channel volume so that the T-shaped end can be introduced into the elongated channel in the insertion orientation and 20 then rotated within the elongated channel to the engagement orientation. The extrusion may have a uniform cross-section shape along at least part of its length. In some embodiments, the extrusion is an aluminium extrusion, and the inwardly projecting overhangs are formed as one piece with the aluminium extrusion. Aluminium may be useful where a relatively light, corrosion-resistant and readily cut extrusion is desired. Other materials suitable 25 for forming an extrusion fixed to the substrate may also be used, provided that the elongated channel, the opening and the opposing inwardly projecting overhangs provide sufficient reaction surfaces for the T-shaped end during application of the compressive force. The elongated channel has a generally U-shaped cross-section with a base and two side walls. The two side walls have opposing inwardly projecting overhangs that project into the channel 30 volume. In some embodiments, the inwardly projecting overhangs project 0.5-5 mm into a volume of the elongated channel or into the channel volume. The inwardly projecting overhangs may be shaped to define a reduced channel opening width relative to a channel width between the side walls, so that the crossbar portion can pass through the opening in the 2026226403   02 Sep 2026 insertion orientation but underlies the inwardly projecting overhangs in the engagement orientation. In some embodiments, each inwardly projecting overhang may comprise a step projecting from the respective side wall into the volume of the elongated channel. The step may be provided at 5 a transition from the side wall to the inwardly projecting overhang. In one example, the transition may include a substantially 90 degree angle between the side wall and a lower face of the inwardly projecting overhang. In other embodiments, the inwardly projecting overhang may be non-linear in shape, or may taper in a linear or non-linear manner back towards a face of the side wall, while still allowing the crossbar portion to be supported beneath the inwardly 10 projecting overhangs in the engagement orientation. The T-shaped end may be proportioned relative to the opening in the elongated channel so that the T-shaped end aligns with the opening in the insertion orientation and the crossbar portion has a width greater than the opening in the elongated channel in the engagement orientation. In some embodiments, rotation of the T-shaped end from the insertion orientation 15 to the engagement orientation comprises rotation sufficient for the crossbar portion to at least partially underlie the opposing inwardly projecting overhangs. In some embodiments, the rotation is in a range from 45 degrees to 90 degrees, from 50 degrees to 90 degrees, from 60 degrees to 90 degrees, from 70 degrees to 90 degrees, or from 80 degrees to 90 degrees. In other embodiments, the rotation is substantially 90 degrees. The dimensions of the crossbar 20 portion, the shaft and the opening may be selected together so that the T-shaped end can be inserted and removed through the gap while still providing positive engagement under the inwardly projecting overhangs during axial draw-up. The bearing face may comprise a plate extending transverse to the shaft. In some embodiments, the plate may be circular, elliptical or polygonal in shape. The shape and area of 25 the plate may be selected to distribute the applied load over exterior regions of the adjacent panels around the gap. The plate may be sized to bear against both adjacent panels when the shaft extends through the gap, thereby assisting the threaded coupling to draw the T-shaped end axially towards the bearing face and urge the exterior faces of the adjacent panels into flush alignment. 30 The threaded coupling between the shaft and the bearing face may be configured so that rotation of the shaft relative to the bearing face advances the bearing face axially along the shaft. In this arrangement, the installer can increase or decrease the compressive force by rotating the shaft relative to the bearing face. The threaded coupling may accommodate 2026226403   02 Sep 2026 variations in panel thickness, adhesive layer thickness and substrate flatness without requiring a different permanent fixing for each installation condition. The threaded coupling may permit substantially continuous axial adjustment of the bearing face relative to the shaft over an available adjustment range. In this context, substantially 5 continuous axial adjustment means that the axial position of the bearing face need not be limited to a small number of predetermined locking positions. Instead, rotation of the shaft relative to the bearing face may allow the installer to select a desired axial position, or a desired extent of axial draw-up, according to the installation condition. In some embodiments, the threaded coupling may have a thread pitch selected to provide fine 10 adjustment of the compressive force applied between the bearing face and the T-shaped end. A finer thread pitch may allow a given angular rotation of the shaft to produce a smaller axial displacement of the bearing face than a coarser thread pitch, thereby allowing the installer to tune the applied compressive force and the resulting panel alignment more carefully. This may be useful where the adjacent panels, adhesive layer, extrusion or substrate have local 15 dimensional tolerances. The threaded coupling may accordingly allow the compressive force to be increased or decreased progressively during installation, rather than requiring the T-slot tool to move between predetermined cam positions or predetermined clamping positions. This can assist the installer to apply only the amount of axial draw-up required to retain the adjacent panels 20 and urge their exterior faces towards flush alignment while curing of the adhesive layer occurs. One or more T-slot tools may be used with one or more extrusions. Mul*ple T-slot tools may be arranged along a single gap, along respec*ve gaps between mul*ple adjacent panels, or across wall, ceiling, soffit or transi*on regions of the substrate. In each case, the tool and channel variants described above maintain the same func*onal rela*onship: the T-shaped end is 25 introduced into the elongated channel through the gap, rotated to the engagement orienta*on, drawn axially towards the bearing face, and subsequently released and removed aSer the adhesive layer has cured. Panel and Substrate Applica<ons 30 The apparatus, system and method may be applied to a range of substrate configurations in which adjacent panels are to be retained and aligned during curing of an adhesive layer. The substrate may comprise a wall, overhang, ceiling, soffit, roof, reveal, head, sill, door, gate, 2026226403   02 Sep 2026 fence, signage panel, or another building frontage, face or generally planar support region. The substrate need not be vertically oriented. For example, the extrusion may be fixed to an angled face or to a horizontal or near-horizontal face, such as a ceiling or soffit, while the T-slot tool applies the compressive force through the gap between adjacent panels during curing. 5 In some embodiments, the substrate may form part of an internal building surface, an external building surface, or a transition between surfaces. For example, the substrate may comprise an internal wall, an external wall, an external or internal corner transition, a wall-to-ceiling transition, a wall-to-soffit transition, a ceiling transition, a soffit transition, or a ceiling-to-soffit transition. In such applications, one or more extrusions may be cut or arranged to follow the 10 relevant substrate geometry so that the opening of the elongated channel remains accessible through the gap between adjacent panels at the required installation location. The substrate may be manufactured from timber, steel, concrete, structural insulated panel material, or another material suitable for receiving the extrusion. In some embodiments, the extrusion may be fastened directly to framing or to the substrate by mechanical fasteners. In 15 this arrangement, a separate wall lining, separate battens, or spacer members need not be provided between the substrate and the extrusion. Direct fixing may be useful where reducing build-up depth is desirable, for example in an interior installation where intrusion into the internal area or volume of a room is to be minimised. The adjacent panels may form a facade, cladding surface, lining surface or decorative surface 20 on the substrate. In some embodiments, the adjacent panels are stone tiles or stone facade panels. The stone may comprise sintered stone, natural stone, limestone, bluestone, engineered stone, or another stone facade product. The adjacent panels may be large-format surfaces or panels, including oblong tiles or sheets having a width or height of at least 0.5 m. Multiple adjacent panels may be adhered to one or more extrusions to form a continuous or 25 interrupted exterior panel surface. The term stone is used in this description for convenience and does not limit the adjacent panels to stone materials. In some embodiments, the adjacent panels may be formed from materials having installation or alignment requirements similar to stone panels, including wood, plastics, composite materials, or other panel materials suitable for adhesive attachment 30   to the extrusion. The T-slot tool may be particularly useful with panels for which visible temporary fasteners are undesirable, because the tool can be introduced through the gap, used to retain and align the adjacent panels during curing, and removed after the adhesive layer has developed sufficient bond strength. 2026226403   02 Sep 2026 The apparatus, system and method may also be used where the gap between adjacent sides of adjacent panels accommodates both tool access and service movement of the panel installation. The gap may allow for expansion or contraction of the adjacent panels relative to the extrusions while also providing access to the elongated channel during installation. In some 5 embodiments, the gap has a width in the range of 0.5 mm to 10 mm, preferably 1 mm to 8 mm, more preferably 2 mm to 8 mm, and still more preferably 3 mm to 6 mm or 3 mm to 5 mm. The gap may run continuously along a length of an extrusion, or may be present at selected positions between adjacent panels where one or more T-slot tools are to be used. In ceiling, soffit, overhang or other non-ver*cal applica*ons, the T-slot tool may assist in 10 resis*ng panel movement away from the extrusion while the adhesive layer cures. In wall, reveal, sill, signage, gate or fence applica*ons, the T-slot tool may assist in reducing localised protrusion or recession between adjacent exterior faces. Across transi*ons, mul*ple T-slot tools may be posi*oned along respec*ve gaps so that the adjacent panels are retained and aligned over a broader installa*on area while maintaining the temporary and releasable nature of the 15 force path described above. Adhesive and Curing Varia<ons Having described suitable panel and substrate applications, the adhesive layer may be selected and applied according to the adjacent panels, the extrusion, the substrate and the 20 environmental conditions expected during installation. The following variations describe example adhesive placement, curing behaviour and post-curing support, while the temporary retention and alignment function remains provided by the T-slot tool during the curing period. The adhesive layer is applied to the exterior face of the extrusion and adheres the at least two adjacent panels to the extrusion while the T-slot tool temporarily retains and aligns the 25 adjacent panels during curing. The adhesive layer may be a commercially available adhesive product having a curing time selected for the installation conditions and the panel material being used. In some embodiments, the adhesive layer may adhere to only part of a rear facing or obscured face of each adjacent panel and to only part of the exterior face of the extrusion. The adhesive 30 layer may extend as an elongated strip along a longitudinal axis of each exterior face of the extrusion. A single strip may adhere to part or all of an adjacent panel. In other embodiments, two strips of adhesive may be located on each extrusion, for example on opposite sides of a width of the extrusion, with each strip of adhesive layer adhering to a separate adjacent panel. 2026226403   02 Sep 2026 This arrangement may allow multiple adjacent panels to be adhered to the extrusion while leaving the gap aligned with the opening in the elongated channel for insertion and removal of the T-slot tool. The adhesive layer may be applied to the extrusion after the extrusion has been fixed to the 5 substrate. This may allow the installer to secure the extrusion mechanically, confirm alignment of the opening with the intended gap location, and then apply the adhesive layer before the adjacent panels are positioned. Alternatively, the adhesive layer may be located on the extrusion before delivery to a site or before installation. In such embodiments, a removable backing may be located over the adhesive layer to reduce contamination of the adhesive layer 10 before the adjacent panels are adhered to the adhesive layer. In some embodiments, the adhesive layer may comprise a chemical adhesive. The adhesive layer may have elastomeric properties to provide resilience and allow some movement between the adjacent panels and the extrusion after curing. Such movement may accommodate thermal expansion, contraction, vibration, substrate movement or other service 15 conditions without requiring the T-slot tool to remain in place after the predetermined adhesive curing period. Curing of the adhesive layer may comprise a period during which the adhesive undergoes a chemical reaction to form a strong and permanent bond between the adjacent panels and the extrusion. Curing may be complete when the adhesive layer hardens or when the adhesive 20 forms cross-linked polymer chains. Different adhesive layers may have different curing time periods, and the curing time may be affected by environmental conditions including temperature and humidity. The predetermined adhesive curing period may be selected based on the adhesive layer, the adjacent panels, the extrusion and the expected installation environment. In some 25 embodiments, the predetermined adhesive curing period may be known to the installer from prior experience, manufacturer instructions, or a selected period known to be well in excess of typical curing times for the adhesive layer. The curing time period may be from 1 minute to 24 hours. During this period, the T-slot tool may maintain the compressive force so that the adjacent panels remain retained relative to the extrusion and their exterior faces remain urged 30 towards flush alignment while the adhesive layer develops sufficient bond strength. ASer curing, the adhesive layer may con*nue to adhere the adjacent panels to the extrusion without the T-slot tool remaining in place. In some embodiments, the adhesive bond longevity may be at least 10 years. The temporary use of the T-slot tool during curing assists the 2026226403   02 Sep 2026 installa*on process without requiring a visible permanent fixing to be leS on exterior faces of the adjacent panels. Advantages 5 The arrangements described above may provide advantages during installation of adjacent panels where an adhesive layer is required to cure before the panels are fully self-supporting relative to the extrusion. The T-slot tool can be introduced through the gap between adjacent panels and engaged with the inwardly projecting overhangs of the elongated channel, so that a temporary clamping action is applied at the same region in which panel-to-panel alignment is 10 to be controlled. This can assist an installer to retain the adjacent panels relative to the extrusion while also urging the exterior faces of the adjacent panels towards flush alignment during the adhesive curing period. The use of the inwardly projecting overhangs as internal reaction surfaces may reduce the need for temporary external braces, visible face fasteners or permanent mechanical fixings on the 15 exterior faces of the adjacent panels. The T-shaped end can be rotated into engagement beneath the overhangs, used to apply the compressive force, and subsequently rotated back for removal through the same gap. As a result, the tool may assist during curing without forming part of the completed visible panel installation. The threaded coupling between the shaft and the bearing face allows the compressive force to 20 be applied progressively. Rather than relying on a fixed spacing or snap-fit engagement, rotation of the shaft relative to the bearing face can adjust the axial draw-up between the bearing face and the T-shaped end. This may allow an installer to compensate for installation tolerances, including variations in panel thickness, adhesive layer thickness, extrusion position, substrate flatness and local panel alignment. 25 The bearing face may distribute load over exterior regions of the adjacent panels around the gap, while the T-shaped end reacts against the overhangs within the elongated channel. This force path can reduce localised point loading at the gap and can help control relative protrusion or recession between neighbouring panels. In applications involving stone, large format panels or other comparatively heavy or stiff panel materials, such load distribution may 30 assist in achieving a more consistent installed surface. Because the T-slot tool is removable after curing, the adhesive layer and extrusion can continue to support the adjacent panels without the tool remaining in place. The gap between the 2026226403   02 Sep 2026 panels may remain available as a joint, expansion space or visual separation between panel edges, while the exterior faces remain free of visible temporary fixing marks associated with the installation tool. Multiple T-slot tools may also be used along one or more gaps to support retention and alignment across a broader installation area during the same curing period. 5 The described arrangement can provide a temporary, adjustable and reversible force path during curing. The extrusion and adhesive layer provide the permanent support structure for the panels, while the T-slot tool provides a removable installa*on aid that assists reten*on, alignment and curing control without requiring a permanent externally visible clamping component. 10 Descrip<on Conclusion The preceding embodiments, examples and variations describe interrelated features that may be combined according to the installation requirements. The extrusion provides the elongated channel, opening and inwardly projecting overhangs that receive and react against the T- 15 shaped end of the T-slot tool. The adhesive layer provides the bond between the adjacent panels and the exterior face of the extrusion. The T-slot tool provides a temporary installation aid that is introduced through the gap, rotated into the engagement orientation, tightened to apply the compressive force, maintained during curing, and removed after the adhesive layer has developed sufficient bond strength. 20 The described features are not limited to a single installation sequence or a single set of dimensions unless expressly required. For example, the extrusion material, substrate configuration, panel material, adhesive form, gap width, overhang projection, bearing face shape, number of T-slot tools and spacing of T-slot tools may be selected to suit the panels and installation environment. In each arrangement, the opening of the elongated channel remains 25 accessible through the gap so that the T-shaped end can cooperate with the inwardly projecting overhangs to establish the temporary and releasable force path during adhesive curing. The apparatus, system and method may be implemented across different building surfaces and panel layouts while retaining the same functional relationship between the extrusion, the 30 adhesive layer, the adjacent panels and the T-slot tool. The extrusion and adhesive layer provide permanent support for the adjacent panels after curing, whereas the T-slot tool provides temporary retention and alignment during curing. This separation between permanent support and temporary installation control allows the exterior faces of the adjacent 2026226403   02 Sep 2026 panels to be urged into flush alignment without requiring the T-slot tool to remain in the completed installation. Although particular embodiments have been described with reference to stone panels, aluminium extrusions, chemical adhesive layers and rotation of the T-shaped end through an 5 angle sufficient for the T-shaped end to at least partially underlie the inwardly projecting overhangs, including through substantially 90 degrees in some embodiments, those examples are provided to illustrate supported implementations. Other disclosed panel materials, substrate orientations, adhesive arrangements, channel configurations and tool arrangements may be used where they provide the claimed engagement between the T-shaped end and the 10 inwardly projecting overhangs and allow the compressive force to be maintained while curing of the adhesive layer occurs. Working Example The following example is provided with reference to the drawings and reference numerals to 15 illustrate one implementa*on of the apparatus, system and method described above. The example may be read together with the preceding aspects, component descrip*ons, varia*ons and advantages, and is not intended to exclude other combina*ons of the disclosed features. 10, 10’ Adjacent panels 20 11, 11’ Adjacent sides 12 Gap between sides 13, 13’ Adjacent panel exterior faces 20 Substrate 25 30 Coupling fixing 31 Mechanical fasteners 40 Extrusion 2026226403   02 Sep 2026 41 Exterior face 42 Elongated channel 43 Opening in elongated channel 44 Base 5   45 Two side walls 46 Inwardly projec*ng overhang 47 Step 48 Channel volume 49 Channel opening width 10 49’ Channel width 60 Adhesive layer 70 T-slot tool 15   71 ShaS 72 Bearing face 73 Plate 74 T-shaped end 75 Crossbar por*on 20 76 Threaded coupling A Inser*on orienta*on B Engagement orienta*on 25 Fc Compressive force 2026226403   02 Sep 2026 As noted above, and now with reference to Figures 1-10, the apparatus and system may comprise a substrate 20 to which the adjacent panels 10, 10’ are to be applied. The apparatus and system comprise a coupling system including extrusions 40. As best seen in Figure 1 and Figure 6, these extrusions 40, 40’ are fixed to the substrate 20. Fixing, best seen in 5 Figure 4 or Figure 8 and Figure 9 may be via mechanical fasteners 31 op*onally also via a coupling fixing 30. The adjacent panels 10, 10’ have adjacent sides 11, 11’ and when applied to the extrusions 40, a gap 12 is leS between the adjacent sides 11, 11’. This gap 12 aligns with an opening 43 in the elongated channel 42 of the extrusion 40. 10 Each extrusion 40 has an exterior face 41. An adhesive layer 60 may be applied as a line to the exterior face 41 or faces of the extrusion 40. The adhesive layer 60 may be applied as a tape, spots, dashes or other ways as well. The elongated channel 42 of the extrusion 40 comprises a generally U-shaped cross-sec*on shown, for example, in Figure 4 or Figure 8-10, with a base 44 and two side walls 45. The two 15 side walls 45 have opposing inwardly projec*ng overhangs 46. About a transi*on from the side wall 45 to an inwardly projec*ng overhang 46 may be a step 47 in profile. This may be a 90 degrees angle transi*on from the side wall face 45 to a lower face of the overhang 46. The generally U-shaped cross-sec*on of the elongated channel 42 has a channel volume 48 defined by the base 44, side walls 45 and overhangs 46. The elongated channel 42 has an opening as 20 noted with a reduced width 49 rela*ve to a width 49’ between the side walls 45 of the elongated channel 42. The apparatus or system further comprises a T-slot tool 70 best shown in Figures 8-9. The T-slot tool 70 comprises a shaS 71, a bearing face 72, a plate 73, and a T-shaped end 74 at one end of the shaS 71. The T-shaped end 74 is insertable through the gap 12 and into the opening 43 in 25 the elongated channel 42 in an inser*on orienta*on A shown in Figure 8. The T-shaped end 74 is rotatable within the elongated channel 42 to an engagement orienta*on B shown in Figure 9, in which the T-shaped end 74 is posi*oned under the inwardly projec*ng overhangs 46. The T-slot tool 70 is then configured to draw the T-shaped end 74 axially towards the bearing face 72 to apply a compressive force Fc via the inwardly projec*ng overhangs 46 on the adjacent sides 30 11, 11’ of the at least two adjacent panels 10, 10’ to urge their exterior faces 13, 13’ into flush alignment on the adjacent panel 10, 10’ exterior, while curing of the adhesive layer 60 occurs. The method of installa*on may comprise the steps of: 2026226403   02 Sep 2026 - providing a substrate 20; - fixing to the substrate 20 an extrusion 40 having an exterior face 41 and defining an elongated channel 42 with an opening 43 in the exterior face 41, the opening 43 aligned with a gap 12 between sides 11, 11’ of adjacent panels 10, 10’. 5        - applying an adhesive layer 60 to the exterior face 41 of the extrusion 40. - adhering at least two adjacent panels 10, 10’ to the adhesive layer 60 such that the sides 11, 11’ of the adjacent panels 10, 10’ define a gap 12 aligned with the opening 43 in the elongated channel 42. The above steps are best seen in Figures 1-3 and 5-7. Aspects of the elongated channel and 10 substrate are also shown in Figure 4. Figures 8-9 show placement of the T-slot tool 70. The method further comprises inser*ng into the gap 12 a T-slot tool 70 comprising a shaS 71, a bearing face 72 and a T-shaped end 74, the T-shaped end 74 being introduced into the elongated channel 42 in an inser*on orienta*on A shown in Figure 8 in which the T-shaped end 74 aligns with the opening 43 in the elongated 15 channel 42. The T-shaped end 74 is then rotated within the elongated channel 42 to an engagement orienta*on B shown in Figure 9 in which the T-shaped end 74 at least par*ally underlies the inwardly projec*ng overhangs 46. The T-shaped end 74 is drawn axially towards the bearing face 72 so as to apply a compressive force Fc via the inwardly projec*ng overhangs 46 against the sides 11, 11’ of the adjacent panels 20 10, 10’. The compressive force Fc may be retained whilst curing of the adhesive layer 60 occurs. The T-slot tool 70 may subsequently be loosened to relieve the compressive force Fc. This may be achieved by rota*ng the T-shaped end 74 back to the inser*on orienta*on A shown in Figure 8 and removing the T-slot tool 70 from the gap 12. 25 Figure 10 illustrates the apparatus and system with the stone panels as the adjacent panels 10, 10’ in both wall and ceiling orienta*ons, and with mul*ple T-slot tools 70 fiWed while the adhesive layers 60 cure and prior to removal of the T-slot tools 70 post curing of the adhesive layers 60. 2026226403   02 Sep 2026 Aspects of the apparatus, system and method have been described by way of example only and it should be appreciated that modifica*ons and addi*ons may be made thereto without depar*ng from the scope of the claims herein.

Claims

1. An apparatus for retaining and aligning adjacent panels during curing, comprising:a substrate;a coupling system comprising an extrusion fixed to the substrate, the extrusion having an exterior face;an adhesive layer applied to the exterior face of the extrusion;at least two adjacent panels adhered to the adhesive layer, adjacent sides of the at least two adjacent panels defining a gap;wherein the extrusion defines an elongated channel with an opening aligned with the gap between the adjacent panels, the elongated channel having a generally U-shaped cross-section with a base and two side walls, the two side walls having opposing inwardly projecting overhangs; anda T-slot tool comprising:a shaft;a bearing face; anda T-shaped end formed at one end of the shaft, wherein the T-shaped end comprises a crossbar portion projecting laterally from the shaft, the crossbar portion having a width greater than the opening in the elongated channel such that, in an engagement orientation, the crossbar portion underlies the inwardly projecting overhangs;wherein the T-shaped end is insertable through the gap and into the opening in the elongated channel in an insertion orientation and is rotatable within the elongated channel to an engagement orientation in which the T-shaped end is positioned under the inwardly projecting overhangs, the T-slot tool being configured to draw the T-shaped end axially towards the bearing face to apply a compressive force via the inwardly projecting overhangs on the adjacent sides of the at least two adjacent panels to urge their exterior faces into flush alignment while curing of the adhesive layer occurs,wherein the T-slot tool further comprises a threaded coupling between the shaft and the bearing face, the threaded coupling being configured to advance the bearing face axially along the shaft upon rotation of the shaft relative to the bearing face, and wherein the bearing face comprises a plate extending transverse to the shaft.2026226403   02 Sep 20262. The apparatus of claim 1, wherein rotation of the T-shaped end from the insertion orientation to the engagement orientation comprises rotation through an angle sufficient for the crossbar portion to at least partially underlie both of the opposing inwardly projecting overhangs.

3. The apparatus of claim 1 or claim 2, wherein the extrusion is an aluminium extrusion, and wherein the inwardly projecting overhangs are formed as one piece with the aluminium extrusion.

4. The apparatus of any one of claims 1 to 3, wherein the inwardly projecting overhangs project from 0.5 mm to 5 mm into a volume of the elongated channel.

5. A system for retaining and aligning panels on a substrate during adhesive curing, the system comprising:a substrate;a coupling system comprising an extrusion fixed to the substrate, the extrusion having an exterior face;an adhesive layer applied to the exterior face of the extrusion;at least two adjacent panels adhered to the adhesive layer, adjacent sides of the at least two adjacent panels defining a gap;wherein:the extrusion defines an elongated channel with an opening aligned with the gap between the at least two adjacent panels, the elongated channel having a generally U-shaped cross-section with a base and two side walls, the two side walls having opposing inwardly projecting overhangs projecting into a channel volume;and the system further comprises:a T-slot tool having a shaft and a bearing face, the tool comprising a T-shaped end formed at one end of the shaft, wherein the T-shaped end comprises a crossbar portion projecting laterally from the shaft, the crossbar portion having a width greater than the opening in the elongated channel such that, in an engagement orientation, the crossbar portion underlies the inwardly projecting overhangs, the T-shaped end being insertable through the gap and into the opening of the elongated channel, the T-shaped end being rotatable within the elongated channel from an insertion orientation, in which the T-shaped end aligns with the opening in the elongated channel, to an engagement orientation, in which2026226403   02 Sep 2026the T-shaped end is positioned under the inwardly projecting overhangs, the tool being configured to draw the T-shaped end axially towards the bearing face to apply a compressive force via the inwardly projecting overhangs on the adjacent sides of the at least two adjacent panels, thereby urging the exterior faces of the at least two adjacent panels into flush alignment while curing of the adhesive layer occurs,wherein the T-slot tool further comprises a threaded coupling between the shaft and the bearing face, the threaded coupling being configured to advance the bearing face axially along the shaft upon rotation of the shaft relative to the bearing face, and wherein the bearing face comprises a plate extending transverse to the shaft.

6. The system of claim 5, wherein rotation of the T-shaped end from the insertion orientation to the engagement orientation comprises rotation through an angle sufficient for the crossbar portion to at least partially underlie both of the opposing inwardly projecting overhangs.

7. The system of claim 5 or claim 6, wherein the extrusion is an aluminium extrusion, and wherein the inwardly projecting overhangs are formed as one piece with the aluminium extrusion.

8. The system of any one of claims 5 to 7, wherein the inwardly projecting overhangs project from 0.5 mm to 5 mm into the channel volume.

9. A method of retaining and aligning panels on a substrate during adhesive curing, the method comprising:providing a substrate;fixing to the substrate an extrusion having an exterior face and defining an elongated channel with an opening in the exterior face, the opening aligned with a gap between sides of adjacent panels, the elongated channel having a generally U-shaped crosssection with a base and two side walls, the two side walls having opposing inwardly projecting overhangs;applying an adhesive layer to the exterior face of the extrusion;adhering at least two adjacent panels to the adhesive layer such that the sides of the adjacent panels define a gap aligned with the opening in the elongated channel;inserting into the gap a T-slot tool comprising a shaft, a bearing face and a T-shaped end, wherein the T-shaped end comprises a crossbar portion projecting laterally from the shaft, the crossbar portion having a width greater than the opening in the elongated2026226403   02 Sep 2026channel such that, in an engagement orientation, the crossbar portion underlies the inwardly projecting overhangs, andwherein the T-slot tool further comprises a threaded coupling between the shaft and the bearing face, the threaded coupling being configured to advance the bearing face axially along the shaft upon rotation of the shaft relative to the bearing face, and wherein the bearing face comprises a plate extending transverse to the shaft;the T-shaped end being introduced into the elongated channel in an insertion orientation in which the T-shaped end aligns with the opening in the elongated channel;rotating the T-shaped end within the elongated channel to an engagement orientation in which the T-shaped end is positioned under the inwardly projecting overhangs;drawing the T-shaped end axially towards the bearing face by rotation of the shaft so as to apply a compressive force via the inwardly projecting overhangs against the sides of the adjacent panels;maintaining the compressive force whilst curing of the adhesive layer occurs; andsubsequently loosening the compressive force, rotating the T-shaped end back to the insertion orientation and removing the T-slot tool from the gap.

10. The method of claim 9, wherein rotating the T-shaped end within the elongated channel comprises rotating the T-shaped end through an angle sufficient for the crossbar portion to at least partially underlie both of the opposing inwardly projecting overhangs.

11. The method of claim 9 or claim 10, wherein the extrusion is an aluminium extrusion, and wherein the inwardly projecting overhangs are formed as one piece with the aluminium extrusion.

12. The method of any one of claims 9 to 11, wherein the inwardly projecting overhangs project from 0.5 mm to 5 mm into a channel volume.

13. The method of any one of claims 9 to 12, wherein maintaining the compressive force comprises retaining the T-slot tool in posi*on during a predetermined adhesive curing period.

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