GB2526834A

GB2526834A - Beam assembly

Info

Publication number: GB2526834A
Application number: GB1409897.4A
Authority: GB
Inventors: Andrew Walter Mcrae Thomson
Original assignee: Ultraframe UK Ltd
Current assignee: Ultraframe UK Ltd
Priority date: 2014-06-04
Filing date: 2014-06-04
Publication date: 2015-12-09
Anticipated expiration: 2034-06-04
Also published as: GB201409897D0; GB2526834B

Abstract

A beam assembly 20 for a roof of a building such as an extension or conservatory comprises a support member 22 connected to an insulation beam 24 having an elongate body of insulating material 80 at least partially covered by a structural sheath 82. The support member may be a glazing bar. One of the insulation beam or the support member may have a pair of shelves 72 for receiving lips 92 projecting from the other. Alignment features limit the relative movement of the support and the beam. An insulating gasket 26 may be provided between the beam and the support to provide a thermal break. The insulation beam may comprise two sub-beams, each containing a separate body of insulating material. Also claimed is a roof structure comprising ridge and eaves beams, along with the beam assembly. A layer of insulation may be mounted to the sheath below the assembly.

Description

Beam Assembly The present invention relates to a beam assembly of the kind that may be used in a roof structure, for example the support structure for the roof of a building extension or a conservatory, an insulation beam for said beam assembly and a roof structure comprising said beam assembly.

A conventional roof, such as may be used for a house extension, is typically formed from timber framing. Eaves beams run around the perimeter of the roof, on top of the walls defining the structure being roofed, and one or more ridge beams define the top edge(s) of the roof. Sloped rafters may be connected at one of their ends to the eaves beams and at the other end to a ridge beam, supporting it. The arched structure formed by the rafters supports roof insulation and tiling. For increased strength, the rafters are often interconnected by additional beams such as collar ties, wind braces, joists, props and purlins, all of which are well-known in the building construction industry.

In the case of a conventional glazed conservatory roof, again the perimeter of the roof is typically defined by eaves beams and the top edge is defined by one or more ridge beams. Interconnection between the eaves beams and ridge beam(s) is provided by glazing bars, which support sheets of glazing material (for example glass or polycarbonate) therebetween.

One problem with glazed conservatory roofs is that they exhibit relatively high thermal conductivity, which can lead to the conservatories below them being too hot during the summer and/or too cold during the winter. Although the thermal properties of glazing have improved significantly as of late, many people now choose a solid (i.e. non-glazed) roof when designing a conservatory. Conventionally, solid conservatory roofs are produced using glazing bars as above, but with the glazing bars supporting solid panels (for instance aluminium-sheathned polyurethane foam panels).

A key consideration in roof design is strength, since a roof must be able to span the distance between walls of the building, and be capable of supporting its own weight as well as the weight of anything resting on top (for instance snow or rainwater) without deflecting beyond acceptable limits. As a guide, the deflection allowed for polycarbonate roof structures is 1/150 of the span, for glass roof structures is 1/175 of the span, and for solid roofs is 1/300 of the span. The particularly low allowable deflection for solid roofs is due to the fact that such roofs are usually finished with a layer of plasterboard, which is prone to cracking and possibly crumbling if subjected to significant deflection. From these figures, it is clear that solid roofs must be significantly stronger than equivalent glazed roofs.

Another factor of particular importance to solid roofs is insulative ability. Whilst glazed roofs are generally exempt, solid roofs must comply with building regulations in terms of insulative ability. As an example, in the UK a pitched roof extension must have a thermal conductivity of no more than 0.18W/m2. The support structure for solid roofs must therefore support significant quantities of insulation such as mineral wool. This increases the weight which must be supported by the roof structure, further increasing the strength requirements placed thereon. The conventional way of improving the strength of a solid conservatory roof is to include more glazing bars, and/or to use larger (and therefore stronger) glazing bars. However, these measures further reduce the thermal performance of the roof, and add considerably to the cost and to the complexity of assembly.

As an additional constraint, whilst in conventional timber roofs insulation can simply be screwed to the wooden beams and rafters, in conservatory roofs screwing insulation to the (metal) glazing bars provides a significant thermal bridge and limits the effect the insulation has on the thermal properties of the roof as a whole.

It is therefore an object of the invention to obviate or mitigate at least one of the aforesaid disadvantages, and/or to provide an improved or alternative beam assembly, insulation beam or roof structure.

According to a first aspect of the present invention there is provided a beam assembly for a roof structure, wherein: the beam assembly comprises a roof support member and an insulation beam, each having a longitudinal axis; the insulation beam and roof support member are configured for attachment to one another with their respective longitudinal axes extending substantially parallel; and the insulation beam comprises an elongate body of insulation material at least partially covered by a structural sheath.

Throughout this specification, by structural sheath" it is meant an outer layer of dissimilar material to the insulation material which provides structural support and adds significant structural strength (for instance it may increase the beam strength of the insulation beam at least twofold (for instance between twofold and threefold) in comparison to the body of insulation alone). Accordingly, it should be understood that a covering of reflective film or other such material on the body of insulation material would not constitute a structural sheath.

Accordingly, such a beam assembly may provide increased strength when used in a roof structure, as compared to a roof support member used in isolation. For instance, the insulation beam may significantly increase the second moment of area of the beam assembly about its neutral axis, and the structural sheath of the insulation beam may provide substantial additional structural rigidity. Furthermore, the addition of the body of insulation material may improve the thermal properties of the beam assembly, and thus of a roof using the beam assembly for support. Still further, the structural sheath of the insulation beam may provide a convenient and/or thermally superior mounting point for other components or assemblies. For example, the sheath may be arranged to be in limited (or no) direct contact with the roof support member, or provide a convoluted thermal pathway thereto, so that any component mounted to the sheath using fasteners does not provide as extensive a thermal bridge as if such a component was mounted directly to the roof support member.

Furthermore, mounting a component to the sheath of the beam assembly may allow said component to be spaced further from the roof support member, so as to provide reduced thermal coupling therewith, without significantly increasing the complexity of the mechanism by which it is mounted. For instance, if a sheet of plasterboard were to be screwed to a roof support member in a conservatory roof, the screws would act as a thermal bridge, allowing heat to travel into the roof support member and escape with relative ease. A conventional solution tc this problem is to screw a wooden batten to the roof support member and screw the plasterboard to that batten, thereby spacing apart the plasterboard and the roof support member. However, this attachment mechanism requires considerably more components, increases the time taken to mount the plasterboard, and could introduce leakage pathways for moisture. In contrast, if the roof support member were replaced with a beam assembly according to the invention, the plasterboard could simply be screwed to the structural sheath. This mounting mechanism would be extremely simple, whilst still allowing the plasterboard to be spaced from the roof support member.

A structural member may be considered to be a structural sheath if it provides an elongate channel (whether open around its periphery like a trough, or closed around its periphery like a tube or a box section) within which the elongate body is at least partially received.

Insulation material may be considered to be a material with a thermal conductivity of no more than 0.04 W/mK. Examples of insulation materials are polyisocyanurate foam, mineral wool, polyurethane foam and sheep's wool.

The body of insulation material may be fully covered around its periphery by the structural sheath (for instance if the sheath is tubular), or may be partially covered and left partially exposed thereby (for instance if the sheath is trough-shaped). The structural sheath may or may not be in contact with the body of insulation material. In some embodiments the body and sheath may be adhered or fused together, or joined using fasteners.

The roof support member may be a glazing bar.

The beam assembly using a glazing bar as its roof support member may be advantageous in reducing the number of specialist additional components which must be included in a roof structure that utilises a beam assembly in place of a glazing bar.

In other words, a roof structure utilising a beam assembly could comprise the same components as a known roof, with the addition of an insulation beam. Such a set of components would be more familiar to workers assembling the roof, in comparison to a structure using a roof support member of a different type. The glazing bar may be a glazing bar of known design. This may be advantageous in allowing insulation beams to be fitted to glazing bars of existing roof structures, and/or produced from new with reduced additional tooling being required.

For the avoidance of doubt, reference to a glazing bar should not be deemed to imply that the glazing bar must support glazing material.

With the roof support member and insulation beam attached to one another, the beam assembly may define a separation direction, which is the direction which intersects the longitudinal axes of the roof support member and insulation beam and is perpendicular to both said axes; and the beam assembly may be provided with connection features configured to limit separation of the roof support member and insulation beam in the separation direction.

In typical use of the beam assembly, the separation direction may be a vertical direction. For the avoidance of doubt, reference to relative movement of the insulation beam and roof support member in the separation direction is intended to include movement with a vector component in the separation direction, for instance movement in a diagonal direction or relative rotation.

Such connection features may be advantageous in reducing the extent to which fasteners must be used to hold the roof support member and insulation beam in position relative to one another in the separation direction. In some embodiments, said connection features may attach the insulation beam and roof support member to one another with sufficient strength that no fasteners are required (at least to hold the roof support member and insulation beam in place in the separation direction). Additionally, the restricted separation of the roof support member and insulation beam may allow for direct force transfer therebetween. For instance, where the separation direction is the vertical direction, vertical force or bending applied to one of the roof support member and insulation beam may be transferred directly to the other. In contrast, if the roof support member and insulation beam were connected by fasteners then force may be transmitted through these fasteners, and this could introduce significant point loading and a consequent reduction in load carrying capacity. Further, separation being restricted in this way may reduce the extent to which the roof support member and insulation beam must be repositioned relative to one another in the separation direction during production and/or transit of the beam assembly, and/or while positioning the beam assembly within a structure such as a roof support structure.

The connection features of the beam assembly may be provided in the form of mutually complementary sets (for example two mutually complementary sets). For instance, the connection features may comprise a first set provided on the insulation beam (for instance the sheath of the insulation beam) and a second set provided on the roof support member.

Said connection features may substantially prevent separation of the roof support member and insulation beam in the separation direction, or may permit said movement to a limited extent.

Said connection features may comprise a pair of shelves projecting from one of the roof support member and the insulation beam in directions which are non-parallel to the separation direction, and a pair of lips projecting from the other of the roof support member and the insulation beam in directions which are non-parallel to the separation direction, the lips being receivable on the shelves.

Preferably, the shelves are provided on the roof support member, and the lips are provided on the insulation beam (preferably on the structural sheath thereof). The lips and/or shelves may each project at an angle of no less 40 degrees to the separation direction, for instance no less than 70 degrees or no less than 80 degrees to the separation direction.

With the roof support member and insulation beam attached to one another, the beam assembly may define an alignment direction, which is the direction which is normal to a plane containing the longitudinal axes of the roof support member and insulation beam; and the beam assembly may be provided with alignment features configured to limit relative movement of the roof support member and insulation beam in the alignment direction.

In typical use of the beam assembly, the alignment direction may be a lateral direction.

For the avoidance of doubt, reference to relative movement of the insulation beam and roof support member in the alignment direction is intended to include movement with a vector component in that direction, for instance movement in a diagonal direction, or relative rotation.

Such alignment features may be advantageous in reducing the extent to which fasteners must be used to hold the roof support member and insulation beam in position relative to one another in the alignment direction. In some embodiments, said alignment features may restrict relative movement sufficiently that no fasteners are required (at least to hold the roof support member and insulation beam in place in the alignment direction). Additionally, the restricted movement of the roof support member and insulation beam in the alignment direction may allow for direct force transfer therebetween. For instance, where the alignment direction is the lateral direction, lateral force or bending applied to one of the roof support member and insulation beam may be transferred directly to the other. In contrast, if the roof support member and insulation beam were connected by fasteners force may be transmitted through these fasteners, and this could introduce significant point loading and a consequent reduction in load carrying capacity. Further, relative movement being restricted in this way may reduce the extent to which the roof support member and insulation beam must be repositioned relative to one another in the alignment direction during production and transit of the beam assembly, and/or positioning of the beam assembly within a structure such as a roof support structure.

The alignment features of the beam assembly may be provided in the form of mutually complementary sets (for example two mutually complementary sets). For instance, the alignment features may comprise a first set provided on the insulation beam (for instance the sheath of the insulation beam) and a second set provided on the roof support member.

Said alignment features may substantially prevent relative movement of the roof support member and insulation beam in the alignment direction, or may permit said movement to a limited extent.

Where a beam assembly has connection features configured to restrict separation of the roof support member and insulation beam in the separation (e.g. vertical) direction, and also alignment features configured to restrain relative movement of the roof support member and insulation beam n the alignment (e.g. lateral) direction, both functionalities may be provided by a single set of features, or each function may be provided by a different set of features.

The beam assembly may further comprise a thermally insulative gasket positionable between respective parts of the roof support member and insulation beam so as to provide a thermal break therebetween.

The gasket may be positionable to provide a thermal break between the roof support member and the structural sheath of the insulation beam, and further may be positionable to provide a thermal break between the entire of the insulation beam and the roof support member.

At least one of the connection features and/or alignment features may be provided on the gasket. For example, where a beam assembly has connection features which comprise a pair of shelves and a pair of lips, one of the shelves and lips may project from the gasket in directions which are non-parallel to the separation direction, and the other of the shelves and lips may project from the roof support member or insulation beam in directions which are non-paralle to the separation direction.

At least one of the connection features and/or alignment features may be provided on one or more brackets.

The brackets may be provided on the roof support member, the insulation beam (for instance the structural sheath thereof), and/or the gasket.

The structural sheath may be made at least partially out of steel.

Alternatively or in addition, the sheath may be made at least partially out of another metal such as aluminium or titanium, or another material such as a polymer or a fibre composite. The sheath may be made entirely, or substantially entirely, out of steel.

The structural sheath being made at least partially out of steel may be advantageous in providing the sheath with sufficient strength (for instance to support components or assemblies mounted thereto, and/or to provide sufficient additional strength or rigidity to the beam assembly as a whole) without requiring the sheath to be unacceptably thick (and therefore bulky and heavy). As an example, although alumnium is less dense than steel it is also weaker, therefore a sheath of a particular strength made of aluminium would be bulkier than, and no lighter than, one made of steeL In addition, the hardness of steel may allow the pull-out strength of a fastener inserted into the sheath to be larger than the same fastener inserted into even a thicker section of a sheath of a material such as aluminium.

The sheath being made at least partially out of steel may also be advantageous in that it can be formed into the required shape by rolling or bending (for instance cold rolling), which places few constraints on the cross-sectional shape of the sheath. In contrast, elongate aluminium components are conventionally extruded, and cost-effective extrusion usually requires a wall thickness of at least 2mm (which may be too bulky and/or heavy) and places constraints on the extent to which sudden changes in wall thickness can be produced.

A portion of the structural sheath may have a thickness of between 0.4mm and 2mm.

Said portion may have a thickness of between 0.7mm and 1.5mm, for instance around 0.9mm. Said portion may be substantially all the structural sheath.

Such a thickness, especially when said portion of the sheath is made of steel, may offer an advantageous compromise between lightness and strength (both in terms of support provided to the beam assembly as a whole, and in terms of strength of support of components attached to the sheath). For example, in many applications the increased strength offered by a thicker portion may be outweighted by the extra bulk and weight, and the reduced weight and bulk of a thinner portion may be outweighed by the reduction in strength.

Furthermore, when mounting components to this portion of the sheath using self-drilling screws the above thickness may provide a beneficial compromise, being sufficiently thin for the sheath to be penetrated by the screw but sufficiently thick for the thread of the screw to achieve sufficient purchase. In contrast, the minimum thickness required of an aluminium sheath to provide sufficient screw pull-out strength may be too thick to be penetrated by the screw without a pilot hole (which during assembly would require a further step of drilling said hole). This compromise may be particularly evident when said portion of the sheath is made of steel.

The insulation beam may comprise two sub-beams, each sub-beam comprising a separate elongate body of insulation material at least partially covered by its own structural sheath.

According to a second aspect of the present invention there is provided an insulation beam for a beam assembly according to the first aspect of the invention.

An insulation beam according to the second aspect of the invention may be fitted (or retrofitted) to a roof support member so as to form a beam assembly according to the first aspect of the invention and provide one or more of the advantages discussed above.

According to a third aspect of the present invention there is provided a roof structure comprising a ridge beam for defining an upper edge of the roof structure, an eaves beam for defining a lower edge of the roof structure, and a beam assembly according to the first aspect of the invention extending between the ridge beam and the eaves beam.

A roof according to the third aspect of the invention may provide advantages in terms of strength, compactness and/or thermal efficiency as discussed above in relation to the first aspect of the invention.

A roof structure as defined above may be the entire roof structure of a room or building, or may be a part thereof. Where it is the latter, the upper and lower edges of the roof structure of the second aspect of the invention may or may not correspond to the upper and/or lower edges of the entire roof structure.

The beam assembly may be positioned within the roof structure with the roof support member positioned generally above the insulation beam, for instance substantially directly above the insulation beam. For the avoidance of doubt, reference to the roof support member being positioned above the insulation beam is intended to refer to the relative positions of these components about the longitudinal axis of the beam assembly. In other words, the angle of the beam assembly relative to the horizontal does not affect whether or not the roof support member is positioned above the insulation beam.

The roof structure may further comprise a layer of insulation positioned beneath the beam assembly and mounted to the structural sheath thereof.

Said insulation being mounted to the sheath of the insulation beam of the beam assembly may allow the mounting mechanism to demonstrate superior thermal performance as described above.

The roof structure may further comprise a layer of ceiling material positioned beneath the beam assembly and mounted to the structural sheath thereof.

Ceiling material, for instance plasterboard or tongue-and-groove sheeting, being mounted in this fashion may allow the mounting mechanism to demonstrate superior thermal performance as described above.

Where the roof structure has both ceiling material and a layer of insulation, the ceiling material may be positioned beneath the layer of insulation. One of the ceiling material and insulation may be mounted to the sheath through the other, for instance the ceiling material may be mounted to the sheath using fasteners and the insulation may simply rest on top of the plasterboard.

The roof structure may further comprise an additional eaves beam, and an additional beam assembly running between the ridge beam and the additional eaves beam, wherein the beam assembly and the additional beam assembly are connected by a support brace.

For example, the roof structure may be of pitched form, with the beam assembly extending along one side of the pitch and the additional beam assembly extending along the other side of the pitch in opposing manner, with the support brace fitted (typically substantially horizontally) therebetween.

The support brace may provide the roof structure with additional rigidity (for instance torsional rigidity) and/or strength. It may take any suitable form, for instance it may take the form of an elongate member positioned in a manner akin to a collar tie of a timber roof structure.

The beam assembly and the additional beam assembly may each comprise one or more of the features discussed above, independent of whether or not the other also comprises said feature. The beam assembly and the additional beam assembly may be substantially identical.

The support brace may be mounted to the beam assembly and the additional beam assembly by the structural sheaths of their respective insulation beams.

The roof structure may comprise two or more beam assemblies running between the ridge beam and the eaves beam (or one of the eaves beams). In this case, the roof structure may further comprise one or more insulation panels positionable between said beam assemblies, for instance at least partially between the insulafion beams of said beam assemblies. Where the roof structure comprises a single beam assembly running between a ridge beam and an eaves beam, insulation panels may be provided on one or both sides of that beam assembly.

According to a fourth aspect of the present invention there is provided a kit of parts for constructing a beam assembly, insulation beam or roof structure according to any of the above aspects of the invention.

For a better understanding, the present invention will now be more particularly described, by way of non-limiting example only, with reference to and as shown in the accompanying drawings (not to scale) in which: Figure 1 is a perspective view of the structure of a conventional roof; Figure 2 is a perspective view of the structure of a conventional glazed roof; Figure 3 is a perspective view of a beam assembly according to a first embodiment of the invention, along with a capping and two panels; Figure 4 is a cross-sectional view of the beam assembly of the first embodiment; Figure 5 is a cross-sectional view of the separate components of the beam assembly of the first embodiment; Figures 6A to 6C are cross-sectional views of a beam assembly according to a second embodiment of the invention, at different stages in its production; Figure 7 is a cross-sectional view of a beam assembly according to a third embodiment of the invention; Figure 8 is a cross-sectional view of a beam assembly according to a fourth embodiment of the invention; Figure 9 is a cross-sectional view of a beam assembly according to a fifth embodiment of the invention; Figures 1 QA to 1 QE are cross-sectional views of beam assemblies according to sixth to tenth embodiments of the invention; Figure 11 is a cross-sectional view of a beam assembly according to an eleventh embodiment of the invention; Figure 12 is a cutaway view of a section of a roof structure according to the first embodiment of the invention; and Figure 13 a perspective view from below of part of the roof structure according to the first embodiment.

Figure 1 shows the skeleton of an exemplary generic roof structure 1A of the type described above, in position atop a structure shown in dotted outline. An eaves beam 2 runs along the top of each wall 4 of the structure, defining the perimeter of the roof 1A. In this case a single ridge beam 6 defines the top edge of the roof. The ridge beam is supported by a number of rafters 8, which also support a roof covering (not shown) such as tiles, insulation and breather membrane that can be fitted above. The rafters 8 are arranged in pairs along the length of the ridge beam 6, usually at a predetermined spacing, and alternate pairs of rafters 8 are provided with (optional) additional structural support in the form of a collar tie 10. One or more walls 4 beneath the roof may not be of uniform construction, and may incorporate features such as windows and/or doors.

A skeleton of an exemplary glazed conservatory roof structure 1 B as described previously is shown in Figure 2 in position atop a conservatory structure shown in dotted outline. As with the generic rocf shown in Figure 1, the glazed roof 16 has eaves beams 2 running along the top of the conservatory walls 4' to define its perimeter, and a ridge beam 6 defining ts top edge. In this case the ridge beam 6 is supported by glazing bars of three different types: -a glazing bar referred to herein as a "transom glazing bar" 12, which extends at a substantially 90° angle to both the ridge beam 6 and the eaves beam 2 to which it is attached; -a glazing bar referred to herein as a "hip glazing bar" 14 (a type of "hip beam"), which extends along a diagonal edge of the roof, from an end of the ridge beam 6 to a corner at which two eaves beams 6 meet; and -a glazing bar referred to herein as a "splay glazing bar" 16, which extends at a non-90° angle to both the ridge beam 6 and the eaves beam 4 to which it is attached.

Between the glazing bars 12, 14, 16, panes of glazing material (not shown) are supported. Again, one or more conservatory walls 4' beneath the roof may not be of uniform construction, and will usually incorporate features such as windows and/or doors.

Figure 3 shows a beam assembly 20 according to a first embodiment of the invention.

The beam assembly 20 may be utilised as a replacement for any of the glazing bars 12, 14, 16 or rafters 8 discussed above in relation to figures 1 and 2, and/or may be used as a beam in another context (for example it may be used as a ridge beam 6 or an eaves beam 2). The beam assembly 20 comprises a roof support member in the form of a glazing bar 22, an insulation beam 24, and a gasket 26 positioned between the glazing bar and insulation beam. The structure of the beam assembly 20 will be described in more detail below.

In Figure 3 the beam assembly 20 is shown supporting two roofing panels 30, in this case supporting them from underneath (from the perspective of Figure 3). A capping 32 is attached to the beam assembly 20 and supports the panels 30 from above. The panels 30 shown in this figure each comprise upper and lower aluminium sheaths 34, 36 separated by a layer of polyurethane foam 38, although as outlined in more detail below panels used in conjunction with a beam assembly according to the invention may take other forms.

In this example the capping 32 is attached to the glazing bar 22 in a known manner using teeth provided on the glazing bar and on the capping 32 which co-operatively form a ratchet mechanism 40. The capping 32 contacts each panel through a flexible sealing strip 46, which is arranged to prevent rainwater from permeating underneath the capping 32 (at which point the polyurethane foam 38 could become wet and lose some of its insulative properties, or the water could work its way into the structure beneath). However, in extreme weather conditions water can penetrate the seal. So as to mitigate or obviate the damage caused by this water, the beam assembly 20 is shaped to provide secondary drainage of any water which does permeate the sealing strips 46. In this case, the glazing bar 22 of the beam assembly 20 provides a pair of elongate troughs 48 in which water can collect before running along the bar and escaping from its end.

Figure 4 shows the beam assembly 20 of Figure 3 in isolation, and Figure 5 shows the glazing bar 22, gasket 26 and insulation beam 24 of the beam assembly separated from one another. The structure of the beam assembly 20 of this embodiment will be described in more detail in relation to these figures. As an initial point, it is envisioned that in most applications the beam assembly 20 will be positioned with the glazing bar 22 at least generally above the insulation beam 24. This orientation is considered to be particularly suitable for generally vertical loading. The beam assembly of this embodiment (and further embodiments discussed below) will therefore be illustrated with the glazing bar positioned above the insulation beam, and features of the beam assembly will be described according to this frame of reference. However, it is to be understood that this orientation should not be construed as limiting. A beam assembly according to the invention may be used in any other suitable orientation, for instance with the glazing bar positioned underneath or beside the insulation beam, according to the requirements of the application in question.

It will be apparent from Figure 3 that the glazing bar 22 and insulation beam 24 are elongate. They each have a longitudinal axis (not visible) which runs into the page from the perspective of Figures 4 and 5. When the glazing bar 22 and insulation beam 24 are attached to one another to form the beam assembly, their respective longitudinal axes run substantially parallel. Further, in this embodiment the beam assembly 20 defines a separation direction -in this case a vertical direction -which intersects said longitudinal axes and is perpendicular to both. The vertical direction is not shown in the figures, but runs vertically from the perspective of Figures 4 and 5. The beam assembly also defines an alignment direction -in this case a lateral direction -which is normal to a plane containing the longitudinal axes of the glazing bar 22 and insulation beam 24. The lateral direction and the vertical direction are therefore perpendicular to one another.

The glazing bar 22 of this embodiment is of known form and is provided as an elongate aluminium extrusion. The axial cross section of the glazing bar 22 (i.e. its cross section in a plane normal to its longitudinal axis) is generally in the shape of an inverted T, having an upright 60 which runs generally in the vertical direction (as described above), with a cross-piece 62 at its lower end which runs generally in the lateral direction. The end of the upright 60 opposite the cross-piece has an attachment region 64 to which the capping (not visible in this figure) is attached. The glazing bar is shaped to act in a manner akin to an I-beam, with the upright 60 functioning as the web, and the cross-piece 62 and the attachment region 64 functioning as the flanges. Each end of the cross-piece 62 has an upstand 70, which in this embodiment projects generally verticaly. The troughs 48 discussed above are each provided between one of the upstands 70 and the upright 60. Each upstand 70 has a connection feature in the form of a shelf 72 on its distal end. In this embodiment the shelves 72 project substantially laterally inwards towards one another, however in other embodiments they may project laterally away from each other.

The insulation beam 24 comprises an elongate body of insulation material 80, and a structural sheath 82. In this embodiment the elongate body 80 is made of polyurethane foam, and is rectangular in axial cross section. The structural sheath 82 is made of steel around 0.9mm thick. In this case, the sheath 82 is made from a single piece of cold-rolled steel sheet. The sheath 82 has a base 84 (positioned substantially laterally) and two sides 86 (positioned substantially vertically) which co-operatively form an elongate channel within which the body 80 of insulation material is received. In this case, the body 80 is fully received within this channel. The sheath 82 covers the body of insulation 80 across three of its four faces. In this embodiment the body 80 and its sheath 82 are of complimentary shape, so with the body 80 received within the channel of the sheath it has a relatively tight clearance therewith. With the body 80 so received, in this embodiment a small air gap 88 is provided between it and the sheath 82. In other embodiments however, the body and sheath may be a tight fit (for instance an interference fit), and/or the body and sheath may be fused together or fixed using adhesive.

Each side 86 of the structural sheath 82 extends upwards beyond the body 80 of insulation material, and terminates in another connection feature, this time in the form of a lip 92. The lips 92 in this embodiment project substantially laterally towards one another, however in other embodiments the lips (where present) may project substantially laterally apart or may project in different directions.

The gasket 26 of this embodiment is made of a length of PVC extrusion. It has a base 100 aligned substantially laterally, with a substantially vertical upstand 102 at each end.

The distal end of each upstand 102 has a shelf 104. In this case, the shelves 104 project substantially laterally towards one another. As shown in Figure 4, when the beam assembly 20 is assembled, the gasket 26 prevents any part of the insulation beam 24 from touching the glazing bar 22. Being made of a thermally insulating material, the gasket 26 creates a thermal break between the insulation beam 24 (in particular the thermally-conductive stee sheath 82) and the glazing bar 22, thereby improving the thermal characteristics of the beam assembly 20 as a whole.

The gasket 26 also has a number of ridges 105 which face towards the cross-piece 62 of the glazing bar 22. These ridges act to space the gasket 26 and glazing bar 22 such that there is minimal contact between the two, i.e. so that there is an air gap between these two components at most points around the periphery of the cross-piece 62. As illustrated in Figure 4, in this embodiment the cross-piece 62 and glazing bar 22 only contact each other at six discrete points -two between the shelves 104 of the gasket and the tips of the shelves 72 of the cross-piece, two between the upstands 70 of the glazing bar and the ridges 105 projecting from the upstands 102 of the gasket, and two between the bottoms of the troughs 48 and the base 100 of the gasket. In this embodiment the ridges 105 projecting from the base 100 of the gasket 26 do not act to space the gasket and the glazing bar apart, however they are present so that they can perform this function when the beam assembly 20 has a glazing bar of a different type (for instance one where the cross-piece has a flat bottom).

To construct the beam assembly, the gasket 26 and glazing bar 22 are attached to one another by sliding them together longitudinally. The insulation beam 24 is then assembled by pulling the lips 92 of the sheath 82 laterally apart, and inserting the body of insulation material 80 between them. Moving the lips 92 outwards flexes the sheath 82, which provides a restorative force urging the lips back to their original position.

Releasing the lips allows them to move back towards each other under this restorative force, narrowing the gap between them and retaining the body 80. To construct the beam assembly 20 from this point, the lips are pulled apart again (or held apart after insertion of the body 80) and the cross-piece 62 of the glazing bar 22 (with the gasket 26) is inserted between them. The lips 92 are then released and move back to the position shown in the figures.

With the beam assembly 20 assembled, the shelves 72 of the glazing bar 22 and the lips 92 of the insulation beam 24 allow the insulation beam to hang' off the glazing bar.

In other words, the lips 92 and shelves 72 function as connection features which limit separation of the glazing bar 22 and insulation beam 24 in the vertical direction. When the beam assembly 20 is assembled as discussed above, the lips 92 of the insulation beam 24 are received on the shelves 72 of the glazing bar 22 (albeit in this case with the shelves 104 of the gasket 26 positioned therebetween). If the glazing bar 22 and insulation beam 24 are urged apart, the undersides of the lips 92 brace against the shelves 72 (in this case through the shelves of the gasket 26) and resist this movement.

In this embodiment, the above connection features substantially prevent movement of the glazing bar 22 and insulation beam 24 vertically away from each other, however in other embodiments limited movement may be permitted (as would be the case, for instance, if the sides 86 were taller so that the lips 92 were spaced further above the shelves 72).

The upstands 70 of the glazing bar 22 and the tops of the sides 86 of the insulation beam 24 maintain the alignment of the glazing bar and insulation beam. In other words, the upstands 70 and sides 86 serve as alignment features which restrain movement of the glazing bar 22 and insulation beam 24 relative to one another in the lateral direction. If the glazing bar 22 and insulation beam 24 are urged to move laterally relative to one another, the laterally inner surface of one of the sides 86 braces against one of the upstands 70 of the glazing bar 22 (through an upstand 102 of the gasket in this case) and resists this movement. For example, from the perspective of Figure 4, if the glazing bar 22 was urged to the left and the insulation beam 24 to the right, the laterally inner surface of the left side 86 of the sheath 82 of the insulation beam 24 would brace against the left upstand 70 of the glazing bar 22 (through the left upstand 102 of the gasket).

In this embodiment, the above connection features substantially prevent relative lateral movement of the glazing bar 22 and insulation beam 24, however in other embodiments limited movement may be permitted (as would be the case, for instance, if the base 84 of the sheath 82 was wider so that the upstands 90 were spaced further apart).

In addition to the above, relative longitudinal movement of the glazing bar 22 and insulation beam 24 is resisted by friction therebetween (through the gasket 26 in this case).

In some cases, relative movement of the glazing bar 22 and insulation beam 24 being restricted may allow the requirement for fasteners joining these components to be eliminated. The insulation beam 24 and glazing bar 22 may be held in position relative to one another through mechanisms such as the above. In other applications the glazing bar and insulation beam may be attached to one another using fasteners, but the reliance on fasteners and/or the number required may be reduced. For instance, a beam assembly may utilise two fasteners at each end, to provide additional support or merely to guard against eventualities (such as the beam assembly receiving a knock of sufficient magnitude to move the glazing bar and insulation beam longitudinally relative to one another).

Where fasteners such as screws or rivets are used to join the glazing bar 22 and insulation beam 24, in many applications it is preferable for them to be inserted through the upstands 70, 90. This limits the extent to which the fasteners can obscure the flow of water along the troughs 48. It may aso be preferable in many applications for the fasteners used to be self-sealing blind rivets. Use of such fasteners can prevent water in the troughs 48 from leaking out along the hole within which the fastener is received.

Although the connection features of this embodiment have been described as the lips 92 and shelves 72, which act on each other through the shelves 104 of the gasket 26, it may instead be considered that some of these connection features are provided by the gasket 26 itself. For example, it may be considered that it is the shelves 102 of the gasket 26 and the lips 92 of the insulation beam which constitute the connection features. Using this interpretation, vertical separation of the glazing bar 22 and insulation beam 24 would be substantially prevented by the lips 92 of the insulation beam bracing against the shelves 104 of the gasket 26. Relative vertical separation of the insulation beam 24 and gasket 26 would thereby be prevented, and since the gasket is mounted to the glazing bar 22 this would also prevent separation of the insulation beam and the glazing bar.

Similarly, it may be considered that the connection features are the shelves 72 of the glazing bar 22 and the shelves 104 of the gasket 26. Under this interpretation, vertical separation of the glazing bar 22 and insulation beam 24 would be substantially prevented by the shelves 104 of the gasket 26 bracing against the shelves 72 of the glazing bar. Vertical separation of the glazing bar 22 and gasket 26 would thereby be prevented, and since the gasket 26 is held within the insulation beam 24 this would also prevent separation of the insulation beam and the glazing bar.

In a similar fashion, although the alignment features of this embodiment have been described as the upstands 70 of the gazing bar and the sides 86 of the insulation beam, which act on each other through the upstands 102 of the gasket 26, it may instead be considered that some of these connection features are provided by the gasket 26 itself. For example, it may be considered that it is the upstands 102 of the gasket 26 and the sides 86 a! the insulation beam which constitute the connection features. Using this interpretation, relative lateral movement of the glazing bar 22 and insulation beam 24 would be substantialy prevented by the sides 86 of the insulation beam bracing against the upstands 102 of the gasket 26. Relative lateral of the insulation beam 24 and gasket 26 would thereby be prevented, and since the gasket is mounted to the glazing bar 22 this would also relative lateral movement of the insulation beam and the glazing bar. As another alternative, it may be considered that the connection features are the upstands 70 of the glazing bar 22 and the upstands 102 of the gasket 26.

Regardless of where the connection features and alignment features are considered to be, Figures 4 and 5 clearly illustrate that the gasket 26 is configured to fit over part of the glazing bar (in this case the cross-piece 62) so as to provide a shape which can interface with the insulation beam 24 with advantageous stability and strength. It will be apparent that if the gasket 26 were removed and the insulation beam 24 re-sized accordingly, the connection therebetween would be weaker and less stable.

Figures 6A-6C show steps in production of a beam assembly 20a according to a second embodiment of the invention. The second embodiment is similar to the first, therefore only the differences will be described here. Corresponding components and features are given the same reference number, along with the suffix a'.

The glazing bar 22a of the second embodiment has a pair of shelves 72a provided on respective upstands 70a of a cross-piece 62a, like the glazing bar of the first embodiment. However, in this case an overhang 120 is provided on the cross-piece 62a above each shelf 72a. Each overhang 120 provides a cavity 124 in its underside.

In this embodiment the gasket 26a extends to cover the overhangs 120, as well as the shelves 72a and upstands 70a of the cross-piece 62a. The beam assembly 20a of the second embodiment also differs from that of the first embodiment in that each lip 92a of the sheath 82a of the insulation beam 24a has its end bent back over itself to produce a thickened portion 126.

To construct a beam assembly 20a according to the second embodiment, as with the first embodiment, the gasket 26 and glazing bar 22 are slid together longitudinally. The lips 92a of the sheath 82a are then pulled laterally apart, and the body of insulation material BOa and the cross-piece 62a of the glazing bar 22a are inserted therebetween.

In this case, however, the cross-piece 62a does not pass fully through the gap between the lips 92a. Instead, it is inserted to the depth at which the spaces between the shelves 72a and underhangs 120 are aligned with the lips 92a. This is shown in Figure 6A, which also illustrates the flexing of the sheath 82a which occurs when the lips 92a are moved apart. The lips 92 are then released, at which point they move back towards each other and are received on their respective shelves 72a (as shown in Figure 6B).

Construction of the beam assembly 20a of the second embodiment, however, includes an additional step. With the lips 92a received on the shelves 72a, the overhangs 120 (and the portions of the gasket 26a covering them) are permanently bent downwards so that they are pressed onto the top of the lips 92a. This is shown in Figure BC. The bending down of the overhangs 120 may be performed through any suitable operation, for instance using a continuous compressive rolling process or an intermittent crimping operation. In this embodiment the overhangs 120 are bent down sufficiently that they are resiliently biased downwards against the lips 92a (through the gasket 26a).

The thickened portions 126 of the lips 92a and the cavities 124 of the overhangs 120 have complementary shapes to one another, so that when the overhangs have been bent down the thickened portions 126 and the cavities 124 interlock (through the gasket 24a). This interlock prevents withdrawal of the lips 92a from the spaces between the shelves 72a and overhangs 120. Any relative lateral movement of the glazing bar 22a and insulation beam 24a would require one of the lips to withdraw from this space. For instance, if the glazing bar moved to the right relative to the insulation beam, this would require the left lip 92a to be withdrawn. Since withdrawal of the lips 92a is prevented by the interlock between the thickened portions 126 and the cavities 124, this interlock also contributes restriction of relative lateral movement of the glazing bar 22a and insulation beam 24a. Accordingly, the thickened portions 126 and cavities 124 may also be considered to constitute alignment features.

The beam assembly 20a of the second embodiment may also provide greater resistance to vertical separation of the insulation beam 24a and glazing bar 22a. It will be apparent that if the insulation beam 24a and glazing bar 22a were urged vertically apart, this would tend to deform the lips 92a and rotate them upwards, and that this upward rotation would produce a resultant force urging the lips laterally apart. The overhangs 120 would hold the lips 92a down and oppose and upward rotation, and the interlock between the thickened portions 126 and cavities 124 would oppose lateral movement of the lips as outlined above.

It will be apparent that there is a greater area of contact between the glazing bar 22a and insulation beam 24a (through the gasket 26a) of this embodiment than was the case in the first embodiment. Accordingly, the friction therebetween is also higher. The friction is further increased by the overhangs 120 being biased against the lips 92a as outlined above. This increased friction increases the strength with which the glazing bar 22a and insulation beam 24a are held in the correct longitudinal position relative to one another. In this embodiment, relative movement of the glazing bar 22a and insulation beam 24a is restricted by the above mechanisms to such an extent that no fasteners are required at all.

Figures 7, 8 and 9 show beam assemblies according to third, fourth and fifth embodiments of the invention respectively. Each of these embodiments are similar to the previous embodiments, therefore only the differences will be discussed here.

Corresponding components and features are given the same reference number, along with the suffixes b, c and d' respectively. Referring to Figure 7, the beam assembly 20c according to the third embodiment s very similar to that of the first embodiment.

Indeed, the insulation beam 24 and gasket 26 of the third embodiment are the same as those of the first embodiment. However, it will be apparent that the glazing bar 22b of this embodiment is of a different (known) design. This glazing bar 22b will not be described in detail, however it is to be noted that in this embodiment the shelves do not project laterally. In this case, the shelves 72b project in directions which are around 45 degrees to the lateral direction (i.e. around 135 degrees to their respective upstands 70b). It should also be noted that in this embodiment the shelves 72b project a much shorter distance from their respective upstands 72b. However, it is to be understood that there is no limit on the size of a surface which may be defined as a shelf', or the angle at which such a shelf must be postioned. Indeed, in some embodiments a shelf' may be provided merely by the distal end of an upstand, with nothing projecting therefrom.

It is particularly apparent in this embodiment that the gasket 26 can act as an adaptor, and can thus provide a section of the glazing bar 22b with a shape which can form an advantageously strong and stable connection with the insulation beam. If the gasket 26 were missing, the angles of the shelves 72b would act to direct the lips 92b apart, reducing the strength with which the gazing bar 22b and insulation beam 24 were prevented from moving vertically apart.

Turning to Figure 8, both the glazing bar 22c and the insulation beam 24c of the beam assembly 20c of the fourth embodiment differ significantly from those of the previous embodiments. Like the glazing bars of the first and third embodiments, the glazing bar 22c is of a known design. While the cross piece of previous embodiments sloped slightly downwards from its central point to each upstand, as described above, in this case the cross-piece 62c is sloped downwards much more noticeably (and the base lOOc of the gasket 26c is shaped complementarily). Like the previous embodiments, the upstands 70c are approximately perpendicular to the overall direction in which the cross-piece 62c projects. Whilst in prevous embodiments the upstands were aligned approximately vertically, due to the sloped shape of the cross piece 62c of this embodiment they are inclined relative to the vertical direction. The shelves 72c, which are substantially perpendicular to their respective upstands 70c, are therefore inclined from the lateral direction.

In relation to the insulation beam 24c, the tops of the sides BSc of the sheath 82c are inclined to match the slope of the upstands 70c of the glazing bar 22c, and similarly the lips 94c of the sheath are inclined to match the slope of the shelves 72c. The shelves 72c and lips 92c still function as connection features to limit vertical separation of the glazing bar 22c and insulation beam 24, and the sides 86c and upstands 70c still function as alignment features to limit relative lateral movement, as discussed in relation the first embodiment. However, due to their incline from the vertical the tops of the sides 86c and upstands 70c also act to limit (and in this case substantially prevent) relative movement of the glazing bar 22c and insulation beam 24c vertically towards one another. If the glazing bar 22c and insulation beam 24c were urged towards one another, the inner surfaces of the tops of the sides 86c would brace against the outer surfaces of the upstands 70c (through the gasket 26c) and oppose this force. In contrast, in the previous embodiments any force urging the insulation beam and glazing bar laterally together would only be resisted by the (potentially relatively weak) body of insulation material.

Unlike the previous embodiments, the insulation beam 24c of this embodiment has an additional structural sheath 136. In this embodiment the additional structural sheath is also made of steel, and is also around 0.9mm thick. Like the sheath 82c, the additional sheath 136 has a base 138 and two sides 140. The additional sheath does not, however, have lips projecting from the tops of its sides 140. Accordingly, for vertical separation of the additional sheath 136 and the glazing bar 22c is to be restricted then additional means (for instance fasteners or adhesive) must be provided.

It is noteworthy that the base 138 of the additional sheath 136 is positioned significantly below the base 84c of the sheath 82c (and thus significantly below the bottom of the elongate body of insulation material 80c). It is therefore spaced further from the neutral axis of the beam assembly and may therefore have a particularly sizeable contribution to the strength of the beam assembly. The presence of the additional sheath may also increase the strength of any attachment to the insulation beam 24c via the sheath 82c.

For example, a screw driven from underneath into the base 84c sheath 82c would also run through the base 138 of the additional sheath 136. The resistance to pull-out of the screw would therefore be approximately double that provided by the sheath 82c alone.

The screw passing through two layers, especially two layers spaced apart as would be the case if it passed through the bases 84c, 138, would also increase its lateral stability.

Although in this embodiment the inner sheath 82c has been denoted the sheath' and the outer sheath 136 the additional structural sheath", this should not be construed as limiting. Since each constitutes a sheath within the meaning of the appended claims, either of the sheaths 82c, 136 may be considered to constitute the sheath', at which point the other would constitute the other the additional sheath'.

Turning now to Figure 9, it will be apparent that the glazing bar 22 of the fifth embodiment is substantially identical to that of the first embodiment. However, in the case of the fifth embodiment the base lOUd of the gasket 26d is shaped to mirror the gentle slope of the portions of the cross-piece 62 which connect the bottom of the upright 60 to the upstands 70. The insulation beam 24 of this embodiment, however, is markedly different. The sheath 82d of this embodiment takes the form of a length of aluminium extrusion, the thickness of which varies considerably. An insulation beam 24 with a sheath 82d of this form may be used when components are to be mounted to the sheath which require particularly high levels of stability. For instance, such a sheath 82d may be used when a support brace (described below) is mounted to a beam assembly 20. The support brace could be mounted to the lowermost, thick sections of the sheath, which would allow it to be mounted particularly rigidly (whereas if it were mounted to a thin steel sheath, the ability of the thin steel to flex may provide a mounting of insufficient stability). Like the sheaths of the previous embodiments, the sheath 82d of this embodiment fully receives the body of insulation material 80 in an elongate channel. However, in this embodiment this channel is formed from two sides 86d and a top 144, rather than two sides and a base. The sheath 82d does not have a base, and thus does not cover the elongate body of insulation material 80 from underneath.

Although in some circumstances the body 80 may remain exposed from below, the beam assembly 20d of this embodiment includes an additional sheath 136d which covers the bottom of the body. The additional sheath 1 36d also physically supports the body of insulation 80, preventing it from falling out from within the sheath 82d (though this would not be necessary in embodiments where the body was attached to the sheath 82d). The additional sheath 136d is made of 0.9mm thick steel, making it a portion of the beam assembly 20d which is particularly suited for the attachment of other components or assemblies for the reasons discussed above. In production of the beam assembly 20d, the additional sheath 136d is attached to the sheath 82d in a manner akin to how the insulation beam of previous embodiments is attached to the glazing bar, with the sheath 82d being provided with shelves 146 and the additional sheath 136d with lips 148.

It will be apparent that in this embodiment no features are provided to restrict relative lateral motion of the glazing bar 22 and insulation beam 24d. Accordingly, in this embodiment the glazing bar 22 and insulation beam 24d must be attached by additional means (not shown) such as using adhesive or fasteners. Whilst in the embodiments the sides 86d of the sheath 82d terminate in a top 144, rather than being free to interact with the upstands 70, alignment features are nonetheless provided. In this case the top 144 of the sheath is provided with a pair of shoulders 147 which brace against the bottoms of the upstands 1 02d of the gasket 26d.

Figures 1 OA to 1 OE show beam assemblies according to sixth to tenth embodiments of the invention. Each of these embodiments use the same glazing bar 22' (and capping 32)', which will be described in relation to the sixth embodiment. Corresponding features and components in Figures 1OA to 1OE are given the same reference number, along with the suffixes f to i' respectively.

Referring to Figure bA, the glazing bar 22' has upstands 70' and shelves 72', as with the previous embodiments, but also has a downward-facing cavity 160. This cavity 160 has a pair of shelves 162 which project substantially laterally inwards towards each other These may be used as connection features as outlined below. Troughs 48' for secondary drainage are provided between the side walls 164 of the cavity 160 and the upstands 70'. As with the first embodiment, the glazing bar 22' of the sixth embodiment forms a ratchet mechanism 40' with a capping 32' in a known fashion which will not be described here.

In the beam assembly 20e of this embodiment, the sheath 82e of the insulation beam 24e forms a box section which substantially fully encloses the body 80e of insulation material. The tops of the sides 86e are bent inwards to co-operatively form a top 144e.

The sides 86e therefore do not project above the body of insulation material 80e sufficiently to form alignment features. Furthermore, no lips are provided on the insulation beam 24e and no alternative connection features are provided. In this embodiment, therefore, the insulation beam 24e is attached to the glazing bar 22e (so as to prevent both vertical separation and relative lateral movement) using fasteners.

More particularly, in this embodiment the insulation beam 24e is attached to the glazing bar 22e using a plurality of self-drilling screws 170 (two of which are shown in Figure 1OA) driven through the cross-piece 62e of the glazing bar, through the base lOOe of the gasket 26e and into the sheath 82e cf the insulation beam.

Turning to Figure lOB, in the seventh embodiment the tops of the sides 8Sf of the sheath 82f act as alignment features, co-operating with the upstands 70' of the glazing bar 22' (through the gasket 261) to restrict relative lateral movement as discussed previously. However, there are no connection features which restrict vertical separation of the glazing bar 22' and insulation beam 241. As with the previous embodiment, this is done using self-drilling screws 170f. In this case, the sides 8Sf of the sheath 82f are shaped to provide oblique surfaces 172 through which the screws 1 70f are driven. The oblique surfaces 172 are angled so that a screw driven therethrough (in a direction normal to the plane of that surface) will project into the cavity 160 but will not breech the troughs 48'. This mechanism allows use of screws 1 70f without obstructing the troughs 48' or providing a leakage path therefrom. This arrangement is also particularly suited to retrofitting insulation beams to existing glazing bars. Since the screws 170f can be driven from underneath, access to the top of the glazing bar 22' (which would require removal of the glazing material supported by that glazing bar) is not required.

In the eighth embodiment, shown in Figure bC, the insulation beam 24g comprises two sub-beams 173, which in this case are disposed laterally adjacent to one another.

In this embodiment the sub-beams 173 are not attached to one another, however in other embodiments they may be joined to one another using any suitable mechanism (for instance using adhesive, fasteners and/or mutually engageable features).

Each sub-beam 173 has its own structural sheath 174 in the form of a box section. The elongate body of insulation material of this embodiment is co-operatively formed by two separate elongate bodies of insulation material 176, one in each sub-beam 173. As with the previous embodiment, the tops of the sides 86g of the insulation beam 24g form alignment features to restrict lateral movement. In this case, however, the two sides 86g are provided by the two separate sheaths 174 of the sub-beams 173.

As with the previous embodiment, the beam assembly 20g of this embodiment is not provided with connection features to restrict lateral separation of the glazing bar 22' and insulation beam 24g. Vertical separation is substantially prevented using self-drilling screws 170g positioned as described in relation to the sixth embodiment. In this case, the screws 170g penetrate into the elongate bodies 176 of insulation material.

They may therefore provide some support to the insulation beam 24g via the insulation material, as well as via the sheath.

Turning now to Figure 1OD, in the ninth embodiment the insulation beam 24h also comprises two sub-beams 1 73h each with a separate sheath 1 74h covering a separate elongate body of insulation 176h. As with many of the previous embodiments, the insulation beam 24h has sides 86g which act as alignment features, and has lips 92h which act as connection features. However, in this embodiment case the lips 92h are not provided on the sides 86h. Instead, they are provided on upstands 178 provided around the lateral mid-point of the insulation beam 24h. Also, in this embodiment the lips 92h project substantially laterally outwards from one another rather than inwards towards one another.

In this embodiment the lips 92h are not received on the shelves 72' at the ends of the cross-piece 62' of the glazing bar, but are instead received on the inward-projecting shelves 162 of the cavity 160. Nonetheless, the lips 92h and these shelves 162 brace against each other to restrict vertical separation of the glazing bar 22' and insulation beam 24h in the same manner as described above. It should also be noted that in this embodiment further lateral support may be provided by the upstands 178 bracing against the ends of the shelves 162 (through the gasket 26h), as well as the tops of the ends 86h of the sheath (again through the gasket 26h).

Although the beam assemblies of the previous embodiments which utilise lips could be assembled by flexing the sheath to separate the lips before inserting the cross-piece of the glazing bar, in this case the position of the lips 92h precludes this assembly method. In this case, the glazing bar 22' and insulation beam 24h are connected by sliding them together longitudinally so that the lips 92h are slid into the cavity 160.

In the tenth embodiment, shown in Figure 1 OE, the beam assembly 20i utiUses a pair of brackets 180 (one of which is shown) positioned at opposite longitudinal ends of the glazing bar 22'. Each bracket has an upper portion 182, a lower portion 184 and a bolt 186 by which the upper and lower portions can be urged towards one another. In this embodiment the lower portion 184 of the bracket 180 has a pair of hooked ledges 188 at its bottom end, and the sheath 82i has a pair of depending portions 190. By hooking the depending portions 190 onto the ledges 188 the insulation beam 24i is prevented from moving vertically away from the bracket 180, and therefore is prevented from verticaly separating from the glazing bar 22'. The ledges 188 and depending portions therefore function as connection features, which limit separation of the glazing bar 22' and insulation beam 24i in the separation (i.e. vertical) direction.

The bracket 180 also provides alignment features. The depending portions 190 of the insulation beam 24i brace against the sides of the lower portion 184 of the bracket 180 to restrict relative lateral movement of the glazing bar 22' and insulation beam 24i in the same manner as described above.

To construct the beam assembly 201, the brackets 180 are mounted to the glazing bar 22'. To do this, the entire bracket may be slid along the glazing bar 22' to the correct position, or the upper portion 182 may be positioned before attaching the lower portion 184 and the bolt 186 thereto. In either case, the bolts 186 are then tightened to hold the brackets 180 in place, clamping the shelves 162 and the base lOOi of the gasket 26i (which is slotted to allow the bolt 186 to pass therethrough) between the upper and lower portions 182, 184. The insulation beam 24i can then be attached, either by sliding it into place longitudinally or by flexing the depending portions 190 and clipping them onto their respective hooked ledges 188.

Figure 11 shows a beam assembly 20] according to an eleventh embodiment of the invention. The beam assembly 20] of this embodiment uses the same glazing bar 22 and insulation beam 24 as the first embodiment, therefore these components will not be described in detail and only differences will be discussed here. Corresponding components and features are given the same reference number as previously used, along with the suffix. The gasket 26j of this embodiment differs from that of the first embodiment in that each shelf 104j of the gasket is provided with a support blade 192.

The blades 192 are positioned to overlie the lips 92 of the insulation beam 24so that when the beam assembly 20j is used to support roofing panels (not visible) these panels are spaced apart from the lips. The gasket 26j of this embodiment therefore not only provides a thermal break between the insulation beam and the glazing bar, as discussed above, but also provides a thermal break between the insulation beam and roofing panels of a roof structure.

Referring briefly to Figures 6A-6C, it will be apparent that the gasket 26a of the beam assembly 20a of the second embodiment would also provide a thermal break between the insulation beam 24a and roofing panels (not visible) supported by the beam assembly 20a. However, returning to Figure 11, the support blades 192 of the eleventh embodiment perform an additional function. In this embodiment the support blades 192 take the form of deformable sealant strips (in this case made of an elastomeric material). They are angled from the horizontal so that when a panel (not shown) is placed on top they are deformed downwards. This deformation produces a seal between the blades 192 and the panel, preventing the passage of moisture therebetween.

A roof structure according to the first embodiment of the invention is illustrated in Figures 12 and 13. As shown in Figure 12, the roof structure comprises eaves beams 2 defining the lower edges of the roof, and a ridge beam 6 defining its top edge. The eaves beams 2 are connected to each other in a known fashion. Similarly, the beam assemblies 20 are attached to the eaves beams 2 and the ridge beam 6 by attaching the glazing bar 22 thereto in a known fashion.

In this embodiment. the beam assemblies 20 are provided in counterposed pairs running between the ridge beam 6 and two opposite eaves beams 2 in a manner akin to that shown in Figure 1. As also shown in Figure 12, the two eaves beams 2 to which the beam assemblies 20 run are provided with a soff it framework 200 which can be used to house electrical cables and lighting units in a known fashion.

As shown in Figure 13, aluminium-skinned polyurethane foam panels 30 are supported by the glazing bars 22 of the beam assemblies 20 and secured by capping 32 in the manner described with reference to Figure 3. Immediately beneath the panels 30 and between the insulation beams 24 are insulation panels 202 (also shown in Figure 12).

These are made of polyurethane foam, and in this embodiment have a reflective foil layer 206 provided on their undersides. Beneath the insulation panels 202 and the insulation beams 24 is a continuous layer 208 of polyurethane foam insulation, which again is provided with a reflective foil layer 206. The layer 208 is mounted to the sheaths 82 of the beam assemblies using self-drilling screws 210 (one of which is visible in this figure). Each screw 210 supports the layer 208 through a large washer 212 which spreads the support from the screw and prevents tearing. Beneath the continuous layer of insulation 208 is a layer of plasterboard panels 214 (one of which is visible in this figure). The plasterboard panels 214 are also secured to the sheaths 82 of the beam assemblies 20 using self-drilling screws 210, though the plasterboard is hard enough that no washers are required.

Returning to Figure 12, the layer of insulation and the layer of plasterboard panels are not shown, but the insulation panels 202 are visible. In this case are the panels 202 are held in place temporarily using a silicone adhesive, however in other embodiments they may simply be propped between the eaves beam 2 and ridge beam 6, or held in place in any other suitable fashion. For instance, the panels 202 may held in place using a temporary auxiliary support. An example of such an auxiliary support comprises a steel strip with one or more magnets along its length. The strip is placed beneath the panels, for instance extending substantially parallel to the ridge beam, and stuck to the sheaths 82 of the beam assemblies 20 using the magnets so as to hold the strip in place. The strip can then be used to support the panels 202 from underneath, and can easily be removed when required.

Figure 12 also shows that in this embodiment the beam assemblies 20 (of which only the bottoms of the sheaths are visible in this figure) of each pair are connected to one another by a support brace 216. Although such additional support is not usually required for conservatory roofs, as outlined above solid roofs must be particularly rigid.

Although the beam assemblies 20 ensure that the panels (30 in Figure 13) are supported by members of sufficient beam strength, the support braces 216 provide additional torsional rigidity where the beam assemblies are attached to the ridge beam 6. The support braces 216 are mounted to the sheaths of the insulation beams of the beam assemblies 20. This limits the thermal coupling between each pair of beam assemblies 20, and avoids the requirement for the insulation panels 202 to be cut away to allow the support braces 216 to reach the glazing bars.

It will be appreciated that numerous modifications to the above described design may be made without departing from the scope of the invention as defined by the appended claims. For instance, in the above embodiments the elongate bodies of insulation material are rectangular in cross section, and are a close fit with their respective sheaths. However, in other embodiments the elongate body may take any other suitable shape, for instance circular, elliptical or hexagonal in cross-section. Similarly, the sheaths may take a different shape. An elongate body of insulation and its sheath may or may not be complementary in shape, and there may or may not be a considerable clearance provided therebetweeen.

Although numerous elongate components have been described, it is to be understood that one or more of these may be made up of multiple sections, which may or may not be joined together. Further, although in the above embodiments the gasket is elongate, in other embodiments a plurality of axially short gaskets may be provided to space the glazing bar and insulation beam apart. Furthermore, although in the described embodiments the gasket completely separates the glazing bar and insulation beam, in other embodiments it may only separate parts thereof (for instance it may separate the glazing bar from the sheath of the insulation beam, but not from the body of insulation material). Still further, although the gaskets of the above embodiments have been described as being extruded separately before being slid together longitudinally, in other embodiments these components may be co-extruded. Alternatively, they may be produced separately and attached to one another using a different method (for instance by flexing the gasket to move its shelves apart, and inserting the cross-piece of the glazing bar therebetween).

Whilst the sub-beams of the eighth and ninth embodiments are provded laterally adjacent to one another, in other embodiments they may take any other suitable configuration. For instance, one may be positioned vertically above the other or one may be positioned within the other. Further, the sub-beams may be spaced apart from one another, either by another component or by an air gap.

The invention being described in relation to supporting aluminium-skinned polyurethane foam panels should not be construed as limiting. A roof structure according to the invention may utilise a different type of panel. For example, one or more of the panels may instead take the form of an extruded polycarbonate panel defining multiple elongate cavities within its thickness. Such panels being made out of transparent polycarbonate are known, and would conventionally be considered to form part of a glazed roof. However, it is contemplated that such a panel may be made of opaque polycarbonate so as to provide part of a solid roof. Such a panel may provide an advantageously close aesthetic match with conventional roof materials.

In a roof structure according to the invention one or more panels may be replaced by sheets of glazing material. Where relatively few panels are replaced with glazing the roof structure may be considered to be a solid roof with one or more windows, and if most or all panels are replaced with glazing then the roof structure may be considered to be a glazed root.

Although providing means to restrict movement of lips oft their position on shelves has only been described in relation to the second embodiment, it is to be understood that other embodiments may utilise such means. Said means may take the form described above, or any other suitable form. For instance, adhesive may be used to secure the lips and shelves relative to one another (whether or not through a gasket), or the shelves and/or lips may be provided with engagement features such as hooks, barbs or teeth. As an example of the latter, the lips of the first embodiment may be provided with depending hooked ends which hook round the edges of the shelves of the gasket.

The described and illustrated embodiments are to be considered as illustrative and not restrictive in character, it being understood that only preferred embodiments have been shown and described and that all changes and modifications that come within the scope of the invention as defined in the claims are desired to be protected. In relation to the claims, it is intended that when words such as "a" "an," at least one," or "at least one portion" are used to preface a feature there is no intention to limt the claim to only one such feature unless specifically stated to the contrary in the claim. When the language "at least a portion" and/or "a portion" is used the item can include a portion and/or the entire item unless specifically stated to the contrary.

Optional and/or preferred features as set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims.

Claims

CLAIMS: 1. A beam assembly for a roof structure, wherein: the beam assembly comprises a roof support member and an insulation beam, each having a longitudinal axis; the insulation beam and roof support member are configured for attachment to one another with their respective longitudinal axes extending substantially parallel; and the insulation beam comprises an elongate body of insulation material at least partially covered by a structural sheath.
2. A beam assembly according to claim 1 wherein the roof support member is a glazing bar.
3. A beam assembly according to claim 1 or 2 wherein: with the roof support member and insulation beam attached to one another, the beam assembly defines a separation direction, which is the direction which intersects the longitudinal axes of the roof support member and insulation beam and is perpendicular to both said axes; and the beam assembly is provided with connection features configured to limit separation of the roof support member and insulation beam in the separation direction.
4. A beam assembly according to claim 3 wherein said connection features comprise a pair of shelves projecting from one of the roof support member and the insulation beam in directions which are non-parallel to the separation direction, and a pair of lips projecting from the other of the roof support member and the insulation beam in directions which are non-parallel to the separation direction, the lips being receivable on the shelves.
5. A beam assembly according to any preceding claim wherein: with the roof support member and insulation beam attached to one another, the beam assembly defines an alignment direction, which is the direction which is normal to a plane containing the longitudinal axes of the roof support member and insulation beam; and the beam assembly is provided with alignment features configured to limit relative movement of the roof support member and insulation beam in the alignment direction.
6. A beam assembly according to any preceding claim further comprising a thermally insulative gasket positionable between respective parts of the roof support member and insulation beam so as to provide a thermal break therebetween.
7. A beam assembly according to claim 6, incorporating any one of claims 3 to 5, wherein at least one of the connection features and/or alignment features is provided on the gasket.
8. A beam assembly according to any one of claims 3 to 7 wherein at least one of the connection features and/or alignment features is provided on one or more brackets.
9. A beam assembly according to any preceding claim wherein the structural sheath is made at least partially out of steel.
10. A beam assembly according to any preceding claim wherein a portion of the structural sheath has a thickness of between 0.4mm and 2mm.
11. A beam assembly according to any preceding claim wherein the insulation beam comprises two sub-beams, each sub-beam comprising a separate elongate body of insulation material at least partially covered by its own structural sheath.
12. A beam assembly substantially as hereinbefore described with reference to figures 4 and Sand in part figure 3, or any one of figures 6A to 11.
13. An insulation beam for a beam assembly according to any one of claims 1-12.
14. A roof structure comprising a ridge beam for defining an upper edge of the roof structure, an eaves beam for defining a lower edge of the roof structure, and a beam assembly according to any one of claims 1-12 extending between the ridge beam and the eaves beam.
15. A roof structure according to claim 14 further comprising a layer of insulation positioned beneath the beam assembly and mounted to the structural sheath thereof.
16. A roof structure according to claim 14 or 15 further comprising a layer of ceiling material positioned beneath the beam assembly and mounted to the structural sheath thereof.
17. A roof structure according to any one of claims 14 to 16 further comprising an additional eaves beam, and an additional beam assembly running between the ridge beam and the additional eaves beam, wherein the beam assembly and the additional beam assembly are connected by a support brace.
18. A roof structure according to claim 17 wherein the support brace is mounted to the beam assembly and the additional beam assembly by the structural sheaths of their respective insulation beams.
19. A roof structure substantially as hereinbefore described with reference to figures 3, 12 and 13.
20. A kit of parts for constructing a beam assembly, insulation beam or roof structure according to any preceding claim.