Patent Description:
A common approach to thermally insulate buildings is to apply a ventilated rainscreen cladding system at the external region of the building. Typically, individual rainscreen panels are supported on a framework that is attached to the building external wall structure in which the framework is formed from brackets and rails to create an air space between the external cladding layer and inner leaf components of the framework system (typically boards). Commonly, the cavity between the external cladding and the inner leaf components is ventilated to the outside air to prevent entrapment of water and avoid humidity and condensation problems. Where it is required to thermally insulate the building, it is common to include one or more layers of insulation material behind the cladding panels. Accordingly, the external surface structure of the building is concealed from the sun, wind and rain to significantly reduce temperature variations at the external structure and accordingly provide a more controlled external environment of the building that is advantageous for the thermal efficiency management of the building interior.

A variety of different rainscreen panel systems have been proposed in which the external cladding layer is separated from the building external wall structure via sub-frame assemblies, intermediate carrier boards and mounting brackets. Such arrangements are commonly referred to as steel framing systems (SFS). Example disclosures can be found in <CIT>; <CIT> and <CIT>.

Documents <CIT> and <CIT> both disclose:.

However, existing systems are not optimised with regard to the thermal insulation between the external cladding layer and the external face of the building. In particular, regions of the steel sub-frame and mounting brackets typically provide an effective thermal bridge between the cladding and the external wall that reduces the effectiveness of any intermediate insulation material and the air gap between the cladding layer and the inner leaf boards. Additionally, conventional arrangements are susceptible to fire damage that may undermine significantly the structural integrity of the cladding assembly and compromise secure attachment at the external region of the building. Accordingly, what is required an external cladding arrangement that addresses the above problems.

It is an objective of the present invention to provide a rainscreen cladding apparatus configured to enhance the thermal isolation of inner leaf components of an external wall cladding structure for a building from the external environment. It is a further specific objective to provide a mounting assembly having protective external rainscreen cladding panels that reduces the magnitude by which the mounting frame assembly transfers heat between the external cladding layers and the building external wall structure including in particular inner leaf components including for example cover boards, plaster boards, timber beams and the like.

It is a further specific objective to provide a bracket for a rainscreen cladding apparatus that is resistant to degradation on exposure to fire so as to maintain structural integrity of the support within the cladding apparatus. It is a specific objective to provide a bracket to reduce the risk of the cladding apparatus moving appreciably or component parts becoming detached or lose at the external region of the building. It is a further specific objective to provide a bracket component for a rainscreen cladding system that is capable of satisfying fire performance standards relating to external wall structures of buildings including in particular BR <NUM> and in particular tests BS <NUM>.

The objectives are achieved by providing a bracket forming part of an external panel based cladding system that reduces the thermal conduction through the bracket and between the cladding layer and the building wall structure. In particular the objectives are achieved via configuring the bracket with an insulation layer attached to a contact face of a foot part of the bracket in which the insulation layer comprises a conductivity of less than <NUM> W/(m·K) at <NUM>. The present bracket is suitable to support outermost components of the external cladding system including in particular external cladding panels to form part of a cladding structure. The present brackets are suitable to form a mounting sub-frame attachable to the external wall structure that may be formed from cover boards typically formed from Gypsum or other suitable materials. Additionally, the present bracket is specifically adapted to form part of a steel framing system (SFS). In particular, the present bracket is suitable for attachment to intermediate carrier boards that are in turn mounted at the external wall structure via a sub-frame assembly.

According to a first aspect of the present invention there is provided a bracket to form part of an external building cladding assembly, the bracket comprising: a foot having a contact face to be positioned to face internally towards the building and attachable to a structural element forming part of the cladding assembly or the building; an attachment element to attach the bracket to an external cladding panel, an intermediate rail or a mount flange securable to the cladding panel; an insulation layer attached to the contact face of the foot to sit intermediate the foot and the structural element; wherein a thermal conductivity of the layer is less than <NUM> W/(m·K) at <NUM>.

Preferably, the attachment element comprises a neck extending perpendicular or transverse from the foot, the neck attachable to an external cladding panel, an intermediate rail or a mount flange securable to the cladding panel. Optionally, the attachment element comprises a flange, connector, aperture, bolts, screws and/or fitting configured to be engaged and to lock with a cooperating element provided at the cladding panel, intermediate rail or mount flange to connect the bracket to such structures as part of a rainscreen assembly at the building external wall.

The thermal conductivities of the layer material as described herein are stated at room temperature or a temperature in the range <NUM> to <NUM>, <NUM> to <NUM> and in particular <NUM> to <NUM> and are stated where the insulation material is provided at a compressive load of <NUM> kPa (2psi).

Optionally, the thermal conductivity of the insulation layer is less than <NUM>, <NUM> or <NUM> W/(m·K) at <NUM>. Optionally, the thermal conductivity of the insulation layer is in the range <NUM> to <NUM> W/(m·K) at <NUM>. Optionally, the thermal conductivity of the insulation layer is in the range <NUM> to <NUM>; <NUM> to <NUM>; <NUM> to <NUM>; <NUM> to <NUM> or <NUM> to <NUM> W/(m·K) at <NUM>. Preferably, the insulation layer comprises a silica aerogel material optionally comprising a fibre coating at a first and/or second surface of the silica aerogel. Optionally, the insulation may be provided at the bracket as a coating resultant from a coating process. Optionally the insulation coating is configured to be self-bonding to the contact face of the foot of the bracket without the need for additional bonding agents or mechanical attachments. Optionally, insulation layer is attached to the contact face of the foot of the bracket via an adhesive or mechanical attachments.

Optionally, the bracket further comprises a detachable mounting base positionable at the contact face of the foot having a generally planar configuration. Preferably, the mounting base comprises at least one slot to receive an attachment bolt or the like. Optionally, the mounting base comprises shoulders projecting upwardly from a mount face, the shoulders positioned at the corners of the mount face. Optionally, a thickness of the mounting base including the shoulders is less than a thickness the insulation layer such that no part of the shoulders is configured to contact the support substrate to which the insulation layer is attached.

Optionally, the insulation layer is formed as a pad and comprises a thermal conductivity that is less than <NUM> W/(m·K) at <NUM>. Optionally, the insulation layer comprises a silica aerogel and a fibre based insulation material having a conductivity in the range <NUM> to <NUM> W/(m·K) at <NUM>. Optionally, the insulation layer comprises: synthetic amorphous silica; methylsilylated silica; polyethylene tetraphthalate or polyester; fibrous glass.

According to the invention, the insulation layer comprises at least one fire retardant component.

Optionally, the fire retardant comprises any one or combination of the set of aluminium hydroxide, aluminium oxide hydroxide, antimony (III) oxide, a clay, a clay within a polymer matrix, an organomodified clay, montmorillonite or compounds or materials including aluminium, phosphorous, nitrogen, antimony, chloride, bromine, magnesium, zinc, a silicate, or calcium silicate.

According to the invention, the flame retardant comprises iron oxide and/or aluminium trihydrate (aluminium hydroxide A1(OH)<NUM>).

Optionally, the insulation layer comprises: silica; a fibrous component preferably fibrous glass; and a flame retardant component. Optionally, the silica is included at <NUM> to <NUM>% by weight; the fibrous material is included at <NUM> to <NUM>% by weight and the flame retardant component is included at <NUM> to <NUM>% by weight.

Optionally, the bracket comprises synthetic amorphous silica at <NUM> to <NUM>% by weight; methylsilylated silica at <NUM> to <NUM>% by weight; fibrous glass at <NUM> to <NUM>% by weight; iron oxide at <NUM> to <NUM>% by weight; and aluminium trihydrate at <NUM> to <NUM>% by weight.

Optionally, the flame retardant component comprises calcium silicate. Optionally, the bracket comprises: synthetic amorphous silica at <NUM> to <NUM>% by weight; methylsilylated silica at <NUM> to <NUM>% by weight; fibrous glass at <NUM> to <NUM>% by weight; calcium silicate at <NUM> to <NUM>% by weight.

Optionally, the bracket comprises a single insulation layer permanently attached to the foot. Optionally, the insulation layer comprises a thickness in a plane substantially perpendicular to the foot of between <NUM> to <NUM>, <NUM> to <NUM>. Such a thickness is optimised to provide sufficient thermal isolation between the bracket and an underlying structure on which the bracket is mounted whilst also maintaining the capability of the bracket to withstand the loading forces transmitted through the cladding assembly due for example to wind shear and the weight of the various components of the assembly.

According to the invention, the bracket comprises strengthening flanges projecting rearwardly from a rear face of the foot to enhance the strength characteristics of the bracket to withstand loading forces, or the brackets comprise ribs projecting from a rear face of the foot with the ribs extending at least partially through the insulation layer that enhance the strength characteristics. Optionally, the flanges or ribs comprise the same or a different material to the bracket and/or insulation material.

Optionally, the bracket further comprises an adhesive provided between the layer and the foot such that the layer is non-detachably mounted at the foot. The adhesive may be a thermal bonding agent, an epoxy or other bonding resin.

Optionally, the bracket and in particular the foot and the neck comprise an aluminium or an aluminium based material.

Optionally, the bracket may comprise an adaptor plate positioned intermediate the contact face of the foot and the insulation layer. Optionally, the adaptor plate may be formed as a plate or block component releasably mountable to the foot of the bracket. The adaptor plate may be attached via the same attachment bolts used to attach the bracket to a substrate board or separate attachments may be provided including bolts, screws, pins, lugs, clips and the like. Optionally, the adaptor plate comprises a thermoplastic material such as polypropylene. Optionally, a thickness of the adaptor plate is greater than a thickness of the foot. Optionally, the adaptor plate may comprise a lip extending along a perimeter of the adaptor plate to sit over and about a perimeter of the foot such that the adaptor plate is configured to overlap onto the foot. Preferably, the adaptor plate is configured such that no part of the foot is positioned in direct contact against the substrate board. The adaptor plate is advantageous to provide structural strength to the bracket by enlarging the footprint and also assist with the thermal isolation between the bracket and the underlying substrate board.

Optionally, the bracket may further comprise a retainer having an open structure to at least partially surround and house the insulation layer, the retainer being releasably attached to the foot. Preferably, the retainer is formed from elongate thin webbing so as to define a cage-like structure. The thickness of the cage material is maintained to a minimum to reduce as far as possible any thermal bridging via the retainer when mounted in position between the bracket and substrate board. Optionally, the retainer is formed as a mesh, gauze, ribbed, webbed or strap-like structure.

Preferably, the retainer comprises attachments to releasably attach to the foot or adaptor plate to releasably mount the insulation layer in contact with the foot or the adaptor plate. The attachments may comprise any form of hooks, clips, pins, screws, bolts, adhesive or the like. Preferably, the attachments comprise a plurality of barbed fingers projecting from lengthwise and/or widthwise extending perimeter edges of the retainer.

According to a second aspect of the present invention there is provided a building cladding assembly to form an external wall region of a building comprising: a plurality of cladding panels positionable in an edge-to-edge arrangement to form an external cladding layer of a building; a plurality of brackets as claimed herein, each attachment element of each bracket attachable to one of the cladding panels, an intermediate rail or mount flange securable to the cladding panels, the foot securable to a structural element forming part of the cladding assembly or the building via the respective insulation layers.

Optionally, the assembly further comprises cladding rails attachable to the necks of the brackets to form a rail support structure on which to mount the cladding panels. The cladding rails may comprise a head and a tail, with the head extending generally parallel to the external cladding boards and the tail extending generally parallel to the neck of the bracket.

Preferably, the assembly further comprises a plurality of cover boards positionable against timber beams that form a part of an external region of the building, the feet of the brackets attachable to the cover boards via the respective insulation layers. Optionally, the cover boards may comprise acoustic plaster boards and the assembly may comprise a single layer or a plurality of layers of cover boards at the external wall of the building.

Optionally, the assembly may comprise a steel frame sub-assembly (SFS) arrangement comprising a sub-frame mountable to a plurality of cover boards positioned to form a part of an external region of the building; a plurality of carrier boards mountable to the sub-frame to provide a sub-cladding layer separated from the cover boards via the sub-frame; and wherein the brackets are mountable to the carrier boards via the respective insulation layers to spatially separate the external cladding layer from the sub-cladding layer.

Optionally, the assembly may comprise a first insulation material positionable between the external cladding layer and the carrier boards. Optionally, the assembly may further comprise a second insulation material positionable between the carrier boards and the cover boards. The insulation material may comprise a fibrous based or mineral based sheet positioned in a gap region between the external cladding panels and the building cover board and/or the region between a carrier board and the building external surface where the system is an SFS cladding assembly.

Referring to <FIG> a bracket <NUM> to form part of a building cladding assembly for cladding an external wall region of a building comprises generally a foot <NUM>, a neck <NUM> extending generally perpendicular from foot <NUM> and a head <NUM> provided at an opposite end of neck <NUM> relative to foot <NUM>. Foot <NUM> comprises a generally planar body having a front face <NUM> and a rear face <NUM>. A pair of elongate slots <NUM> extend through foot <NUM> between faces <NUM>, <NUM> to receive attachment bolts for securing bracket <NUM> in position within the cladding assembly. Neck <NUM> projects from front face <NUM> to separate head <NUM> from foot <NUM>. According to the specific implementation, foot <NUM>, neck <NUM> and head <NUM> are formed integrally from aluminium so as to provide a generally rigid structure. Head <NUM> comprises a pair of opposed plates <NUM> that are spatially separated from one another to provide a mouth or gap region <NUM>. One or both plates <NUM> are hingeably mounted together at rearward edge <NUM> such that plates <NUM> may be resiliently separated at edge <NUM> to increase the size of mouth <NUM> when mounting a flange or tail part of a rail system that in turn supports external cladding panels.

According to further specific implementations, head <NUM> may be formed from a single piece or component and comprise apertures to receive mounting bolts, pins, screws etc to secure bracket <NUM> to a rail or flange supporting the cladding panels. Other head <NUM> mechanisms may also be envisaged such as bayonet attachments, tongue and groove arrangements, click-lock attachments, push fit connections etc..

Bracket <NUM> further comprises a thermal insulation layer <NUM> non-detachably mounted at foot rear face <NUM>. According to the specific implementation, the low thermal conductivity pad <NUM> is attached to rear face <NUM> via an adhesive such as an epoxy resin. Pad <NUM> also comprises a pair of elongate slots <NUM> being dimensioned and positioned to align respectively with the slots <NUM> (extending through foot <NUM>) to receive attachment bolts. According to the specific implementation, pad <NUM> comprises a material having a thermal conductivity of <NUM> to <NUM> W/(m·K) at a mean temperature of <NUM> to <NUM> and as measured as a compressive load of <NUM> kPa. In one implementation, pad <NUM> comprises Cryogel™ available from Aspen Aerogels, Inc. , NA <NUM>, USA. Pad <NUM> comprises a thickness in a plane perpendicular to face <NUM> of <NUM> to <NUM> and incorporates the silica aerogel material and a flexible fibre coating provided at a front face <NUM> and/or a rear face <NUM> of pad <NUM>. An epoxy or thermal bonding agent is provided to permanently attach pad <NUM> via front face <NUM> to the rear face <NUM> of foot <NUM>.

Referring to <FIG>, bracket <NUM> is suitable for inclusion within an external rainscreen cladding system that is configured as an external wall structure of a building. The building interior is defined by an acoustic plaster board <NUM> that represents an inner leaf of the system having a rear face <NUM> that is internal facing within the building. Timber studs (beams) <NUM> are, in turn, mounted to an external facing mount face <NUM> of plaster board <NUM>. A composite board <NUM> is secured to a front face <NUM> of timber studs <NUM> via a rear face <NUM>. Accordingly, composite board <NUM>, studs <NUM> and plaster board <NUM> represent inner leaf components of the external wall structure that may be regarded as an external wall of the building. A plurality of the brackets <NUM> are secured directly to a mount face <NUM> of composite boards <NUM> (alternatively termed cover boards) via mating contact with pad rear face <NUM>. Each bracket <NUM> is secured to each cover board <NUM> via attachment bolts <NUM> that extend through foot <NUM> having bolt heads <NUM> positioned against front face <NUM>. Accordingly, foot <NUM> is thermally isolated from cover board <NUM> via pad <NUM>. Each bracket head <NUM> is secured to a tail member <NUM> that forms a rearward part of a panel mounting rail assembly <NUM>. In particular, tail member <NUM> is formed as an elongate plate at least partially received within mouth <NUM> between bracket plates <NUM> so as to be gripped by frictional contact to securely mount rail <NUM> at brackets <NUM>. Accordingly, tail member <NUM> is aligned generally parallel with bracket plates <NUM> and neck <NUM> and generally perpendicular to foot <NUM>, insulation pad <NUM> and cover board <NUM>. A rail head <NUM> also extends perpendicular to tail member <NUM>. Rail head <NUM> comprises a mount face <NUM> for positioning in contact and attachment to a rear face <NUM> of a plurality of cladding panels <NUM>. Each panel <NUM> comprises an external face <NUM> that represents an external-most part of the cladding assembly. Due to the respective lengths of bracket neck <NUM>, head <NUM> and tail member <NUM>, a spatial gap <NUM> is created between cover board <NUM> and cladding panels <NUM>. According to a further embodiment, a sheet insulation material may be positioned in the gap region <NUM> between cover board mount face <NUM> and external cladding panel rear face <NUM> to enhance the thermal partitioning of external cladding panels <NUM> and boards <NUM> and <NUM>.

Bracket insulation pad <NUM> is effective to minimise the thermal conductivity from the external cladding panels <NUM> to the cover board <NUM> at the region immediately behind foot <NUM>. That is, the region of foot rear face <NUM> would otherwise provide a thermal bridge to between panels <NUM> and cover boards <NUM>. By utilising pad <NUM> of a low thermal conductivity material, bracket <NUM> thermally isolates the inner leaf plaster board <NUM>. To further enhance thermal isolation, suitable low thermal conductivity washers or flanges may be provided under bolt heads <NUM> to thermally isolate bolts <NUM>, <NUM> from the metallic foot <NUM>.

<FIG> illustrates a further embodiment of the present invention forming part of a steel framing system (SFS) cladding assembly. According to the further embodiment, the building external wall is, in part, defined by a sub-frame assembly that comprises an innermost plaster board <NUM> as described with reference to <FIG> representing an innermost component of the assembly. According to the arrangements of <FIG> and <FIG>, a plurality of boards <NUM> may be provided as the innermost components of the assembly to provide acoustic insulation in addition to enhanced thermal insulation. The sub-frame assembly comprises a plurality of lightweight steel frame support members <NUM> attached directly to mount face <NUM> of plaster board <NUM>. Cover boards <NUM> (alternatively termed a carrier boards) are mounted at an opposite side of the support members <NUM> via carrier board rear face <NUM>. Accordingly, a spatial gap <NUM> is created between carrier boards rear face <NUM> and plaster boards mount face <NUM>. A plurality of brackets <NUM> are then attached to a front face <NUM> of carrier boards <NUM> via contact between rear face <NUM> of insulation pad <NUM> and carrier board front face <NUM> as detailed with reference to <FIG>. Accordingly, carrier boards <NUM> are positioned intermediate brackets <NUM> and steel frame support members <NUM>. The external-most layer of cladding panels <NUM> are mounted at the brackets <NUM> via the rail assembly <NUM> as described with reference to <FIG>. Also, according to the further specific implementation, brackets <NUM> are secured to carrier board <NUM> via the same bolts <NUM>, <NUM> as described with reference to <FIG>. According to further embodiments, bolts <NUM>, <NUM> may be configured to extend through carrier boards <NUM> and into respective steel frame support members <NUM>. As will be appreciated, frame support members <NUM> may be attached to carrier boards <NUM> via respective attachment bolts, screws, pins etc. As with the embodiments of <FIG>, should it be required to enhance the thermal isolation between cladding panels <NUM> and plaster board <NUM>, a first layer of insulation material (not shown) may be positioned within gap region <NUM> and layered onto front face <NUM> of carrier boards <NUM>. Additionally, a second layer of insulation material (not shown) may be positioned within gap region <NUM> in contact between carrier board rear face <NUM> and/or cover board mount face <NUM>.

According to the embodiments of <FIG>, the present bracket assembly <NUM> is advantageous via the low thermal conductivity of pad <NUM> to provide a rainscreen cladding assembly of reduced total thickness between inner leaf board <NUM> and cladding panels <NUM>.

In one implementation and referring to <FIG> pad <NUM> may be attached to bracket <NUM> via an intermediate adaptor indicated generally by reference <NUM>. Adaptor <NUM> comprises a generally planar base <NUM> having an underside surface <NUM> and a support surface <NUM>. Underside surface <NUM> is configured for positioning against and in contact with rear face <NUM> of foot <NUM> and comprises slots <NUM> positioned and dimensioned to correspond to slots <NUM> to receive attachment bolts so as to anchor bracket <NUM> to a suitable support substrate (i.e., boards <NUM>). Base <NUM> comprises four shoulders <NUM> positioned at each corner <NUM> of base <NUM> that project upwardly a relatively short height/distance from support surface <NUM>.

Each shoulder <NUM> is formed as a relatively thin border section projecting from each corner <NUM> and extending a short lengthwise and widthwise distance along a part of the perimeter edge that defines support surface <NUM>. A thickness of each shoulder <NUM> in the plane of support surface <NUM> is significantly less than a thickness of base <NUM> in a plane perpendicular to the plane of support surface <NUM>. Accordingly, should any one of the shoulders <NUM> contact the substrate to which pad <NUM> is attached (for example under extreme compression) any thermal bridging effect through shoulders <NUM> is minimised and may be regarded as negligible. Shoulders <NUM> are configured to facilitate mounting of pad <NUM> on support surface <NUM> and are not intended to provide structural support and in particular to enhance the surface area contact between the bracket and the substrate board <NUM>. The present bracket is constructed such that the pad rear face <NUM> provides exclusively the contact of the bracket <NUM> onto the support substrate <NUM> so as to maximise the thermal isolation function of the present bracket <NUM>. Base <NUM> and in particular support surface <NUM> is configured to support pad <NUM> (illustrated with dashed lines) with pad <NUM> having a footprint or surface area corresponding to that of support surface <NUM> and the rear face <NUM> of bracket <NUM>. The height of each shoulder <NUM> is appreciably less than a thickness of pad <NUM> (in the plane perpendicular to the plane of support surface <NUM>) such that even under compression, pad <NUM> provides the exclusive contact and intermediate coupling between the support substrate <NUM> and the foot <NUM>. That is under normal loading conditions, no part of each shoulder <NUM> is capable of contacting the support substrate.

A further specific implementation of the bracket and adaptor of <FIG> is detailed according to <FIG>. According to the further implementation, bracket <NUM> comprises the same features as described with reference to <FIG> including for example but not limited to the foot <NUM>, neck <NUM>, head <NUM> and associated components and features. According to the further specific implementation, an adaptor plate <NUM> is formed from a polypropylene thermoplastic and comprises a support surface <NUM> for positioning in contact against the rear face <NUM> of foot <NUM>. Adaptor plate <NUM> also comprises an opposed underside surface <NUM> for positioning against insulation layer <NUM>. As described with reference to <FIG>, a plurality of elongate slots <NUM> are formed through plate <NUM> between the opposed faces <NUM>, <NUM>. Plate <NUM> also comprises a raised edge <NUM> in the form of a lip or step extending around a perimeter of plate <NUM> along the lengthwise and widthwise extending perimeter edges. Plate <NUM> and edges <NUM> are dimensioned to sit over and about foot <NUM> such that foot <NUM> is at least partially housed within the recess defined by the upstanding adaptor plate edges <NUM>. Elongate slots <NUM> are dimensioned so as to be co-aligned with slots <NUM> extending through foot <NUM> such that plate <NUM> is capable of being releasably mountable at foot <NUM> via the attachment bolts <NUM>.

Referring to <FIG>, bracket <NUM> also comprises a retainer indicated generally by reference <NUM>. Retainer <NUM> comprises an open or cage-like structure to at least partially house pad <NUM> within an internal region indicated generally by reference <NUM>. Region <NUM> is defined by a plurality of interconnect elongate struts that collectively define a containing frame having the cage-like structure. In particular, a set of lengthwise and widthwise extending struts 604b define a perimeter footprint of the retainer <NUM> with the lengthwise and widthwise struts 604b connected via corner struts 604c that together define a cuboidal open cage structure defining internal cavity region <NUM>. The structure is supported by a set of bracing struts 604a that extend between struts 604b and across side faces of the retainer <NUM> and a rear face <NUM>. An opposed contact face <NUM> of retainer <NUM> is generally open and is not obstructed by support struts 604a. Accordingly, with pad <NUM> located within cavity <NUM>, the majority and in particular at least <NUM> or <NUM>%, of the planar pad front face <NUM> is exposed for contact against the underside surface <NUM> of adaptor plate <NUM>.

Accordingly, when retainer <NUM> is mounted in position and in contact against adaptor plate <NUM>, the underside rear face <NUM> of pad <NUM> is largely exposed for contact against the cover board <NUM> when bracket <NUM> is mounted in position within the external rainscreen cladding system as described referring to <FIG> and <FIG>.

Retainer <NUM> is releasably mountable at adaptor plate <NUM> via a set of attachment clips that project from retainer contact face <NUM>. In particular, retainer <NUM> and in particular lengthwise and widthwise extending struts 604b comprises fingers <NUM> that project outward from and perpendicular to front face <NUM>. Each finger <NUM> comprises a barb <NUM> directed inwardly towards pad front face <NUM>. The length of each finger <NUM> is greater than a thickness of adaptor plate <NUM> so as to allow barbs <NUM> to be resiliently biased against and to hook over the raised adaptor plate edges <NUM> at plate face <NUM>. Accordingly, with pad <NUM> housed within the cage-like retainer <NUM>, pad <NUM> may be releasably clipped into contact with the bracket <NUM> via the mating of the retainer <NUM> onto adaptor plate <NUM> that is in turn secured to foot <NUM>.

The configuration of <FIG> is advantageous to provide thermal isolation of bracket <NUM> and composite board <NUM> via the intermediate positioned adaptor plate <NUM> and pad <NUM>. Adaptor plate <NUM> also assists with the thermal isolation of bracket <NUM> and board <NUM> by providing an additional body of relatively low thermal conductivity between bracket <NUM> and board <NUM>. The configuration of adaptor plate <NUM> and retainer <NUM> and in particular the cage-like structure of retainer <NUM> is advantageous to impart sufficient structural strength to the insulation layer <NUM> and to avoid loading induced deflection of the insulation layer assembly when mounted in position within a rainscreen system of <FIG>. That is, the retainer <NUM> and the adaptor plate <NUM> when coupled together are capable of transmitting load from the bracket <NUM> to the board <NUM> via attachment bolts <NUM>. Accordingly, the subject invention is advantageous to provide both the desired structural attachment strength whilst achieving the desired thermal isolation of the various components of the rainscreen system of <FIG>.

Example materials of the thermal isolating pad <NUM> are detailed below. The following examples are not limiting and the subject invention includes other alternative specific implementations having constituent materials that differ from those indicated. The relative concentrations of the constituent materials may also be selected to suit specific applications.

Pad <NUM> comprises a material composition comprising components having thermal insulation characteristics including in particular silica particulate based materials. Preferably, the material of pad <NUM> comprises at least one fibrous component. According to the example <NUM>, pad <NUM> comprises a foil cover provided at one or both faces. The constituents of the material of pad <NUM> according to example <NUM> are detailed in table <NUM>.

Bracket <NUM> comprising pad <NUM> according to the subject invention is advantageous to provide thermal performance enhancement over existing bracketry arrangements. The thermally isolating characteristic of the subject bracket <NUM> is achieved, in part, as the contact surface area of pad rear face <NUM> is at least equal to or greater than rear face <NUM> of foot <NUM> such that no part of foot <NUM> is capable of contacting the support substrate onto which bracket <NUM> is mechanically attached. Additionally, due to the aerogel and fibrous composite material, pad <NUM> is capable of compression in use as bracket <NUM> is secured to the support substrate (board <NUM>) via attachment bolts <NUM> without any reduction in the thermal conductivity resistance of pad <NUM>.

The present pad <NUM> is further advantageous to provide the desired structural performance and in particular to withstand shear and torsional forces transmitted through bracket <NUM> when bracket <NUM> is installed within an external cladding system according to <FIG> and <FIG>. That is, bracket <NUM> due to the choice of material of pad <NUM> is not configured to deflect appreciably in a vertical plane due to shear loading and also not to twist about its longitudinal axis due to torsional forces. Bracket <NUM> achieves the desired minimal deflection during use as it comprises a single pad only mounted at one end of the bracket. In one implementation, the pad comprises a density in a range <NUM>/cm<NUM> to <NUM>/cm<NUM>.

In some specific implementations and under example <NUM>, pad <NUM> comprises at least one fire retardant component. According to example <NUM>, pad <NUM> further comprises a material composition comprising silica particulate based components having thermal insulation characteristics and at least one fibrous component including for example fibrous glass.

Where the pad <NUM> comprises a fire retardant composition, the fire retardant may comprise a metal oxide, a metal hydroxide, aluminium hydroxide, aluminium oxide, aluminium oxide hydroxide, or compounds including aluminium, phosphorous, nitrogen, antimony, chlorine, bromine, magnesium or zinc. Optionally, the fire retardant comprises a clay within a polymer matrix including at least one organomodified clay. Optionally, the clay comprises a montmorillonite. In some implementations, the fire retardant component comprises an inorganic compound such as antimony (III) oxide (Sb<NUM>O<NUM>). The constituents of the material of pad <NUM> according to example <NUM> are detailed in table <NUM>.

In specific implementations, pad <NUM> is configured to withstand high temperature environment typically associated with a fire. Preferably, the fire retardant is included at a concentration of <NUM> to <NUM>% by weight. The flame retardant is configured to provide a pad <NUM> that does not disintegrate or decompose when exposed to temperatures of up to <NUM>. Accordingly, in such implementations, bracket <NUM> is configured to exhibit no or only minor deflection under loading (as would typically be encountered when bracket <NUM> is mounted within the cladding systems of <FIG> and <FIG>) during and following exposure to fire. Accordingly, the structural integrity of the external cladding systems of <FIG> and <FIG> is maintained even in the event of a fire at the external cladding assembly enabling bracket <NUM> to satisfy further international standards such as EN <NUM> (BR <NUM>) - Fire Performance of External Thermal Insulation for Walls of Multistorey Buildings. In particular the present bracket <NUM> comprising a material of example <NUM> (Pyrogel™) is capable of satisfying the (BR <NUM>) BS <NUM> and EN <NUM>-<NUM>/<NUM> test criteria. According to example <NUM>, pad <NUM> does not comprise a foil cover provided at one or both faces.

Example <NUM> is a variation of example <NUM> in which pad <NUM> comprises at least one fire retardant component in addition to comprising silica particulate based components having thermal insulation characteristics and at least one fibrous component including for example fibrous glass.

The fire retardant may comprise a silicate, belite, calcium monosilicate, calcium hydrosilicate, calcium metasilicate, calcium orthosilicate, grammite, or Ca<NUM>SiO<NUM>. The constituents of the material of pad <NUM> according to example <NUM> are detailed in table <NUM>.

In specific implementations, pad <NUM> is configured to withstand high temperature environment typically associated with a fire. Preferably, the fire retardant is included at a concentration of <NUM> to <NUM>% by weight. The flame retardant is configured to provide a pad <NUM> that does not disintegrate or decompose when exposed to temperatures of up to <NUM>. Accordingly, in such implementations, bracket <NUM> is configured to exhibit no or only minor deflection under loading (as would typically be encountered when bracket <NUM> is mounted within the cladding systems of <FIG> and <FIG>) during and following exposure to fire. Accordingly, the structural integrity of the external cladding systems of <FIG> and <FIG> is maintained even in the event of a fire at the external cladding assembly enabling bracket <NUM> to satisfy further international standards such as EN <NUM> (BR <NUM>) - Fire Performance of External Thermal Insulation for Walls of Multistorey Buildings. In particular the present bracket <NUM> comprising a material of example <NUM> (Spaceloft™) is capable of satisfying the (BR <NUM>) BS <NUM>, and EN <NUM>-<NUM>/<NUM> test criteria as an A2 rating and ASTM E <NUM> fire test as a Class A rating. According to example <NUM>, pad <NUM> does not comprise a foil cover provided at one or both faces.

Claim 1:
A bracket to form part of an external building cladding assembly, the bracket comprising:
a foot having a contact face to be positioned to face internally towards the building and attachable to a structural element forming part of the cladding assembly or the building;
an attachment element to attach the bracket to an external cladding panel, an intermediate rail or a mount flange securable to the cladding panel;
an insulation layer attachable to the contact face of the foot to sit intermediate the foot and the structural element;
wherein a thermal conductivity of the layer is less than <NUM> W/(m·K) at <NUM>;
wherein the insulation layer comprises:
• silica;
• fibrous glass; and
• a flame retardant component being iron oxide and/or aluminium trihydrate (aluminium hydroxide Al(OH)<NUM>); and
wherein to enhance strength characteristics of the bracket to withstand loading forces, the bracket comprises either strengthening flanges projecting rearwardly from a rear face of the foot, or ribs projecting from a rear face of the foot with the ribs extending at least partially through the insulation layer.