GB2453316A

GB2453316A - Glazing support structure for roof light

Info

Publication number: GB2453316A
Application number: GB0715965A
Authority: GB
Inventors: William Buchanan Hawker; Robert James Black
Original assignee: BRETT MARTIN DAYLIGHT SYSTEMS Ltd
Current assignee: BRETT MARTIN DAYLIGHT SYSTEMS Ltd
Priority date: 2007-08-16
Filing date: 2007-08-16
Publication date: 2009-04-08
Also published as: GB0715965D0

Abstract

A glazing support structure for a roof light comprises a curb structure 10 extending along the lower edge of roof light for anchoring to a substrate. Curb 10 and glazing bars (8, Fig 8) each comprise an inner portion 40, (12) outer portion 41, (13) and thermal break 42. Inner portion 40 supports the inner surface of glazing panel 6 and the inner portion of bars (8), while the outer portion of curb 10 seals against glazing panel 6. The lower ends of the glazing bars (8) are enclosed by curb 10. Thermal break 42 may comprise two parallel strips of insulating material, which may be polyamide material, and may be parallel to flat surface 43. Thermal break 42 may be a co-extrusion with curb 10. Seals 78 may be reversibly mounted on a clamping plate 64 attached to curb 10. There is an independent claim for curb base 38 with separate support member 50. The support 50 may rest in a channel 48 in the base 38, and different types of support (50b, Fig 11) may be used for supporting glazing panels 6 in different orientations.

Description

TITLE

Rooflight support structures

DESCRIPTION

Technical field

The invention relates to support structures for glazing panels that form a rooflight or similar construction. The glazing panels are typically, though not exclusively, planar and the support structure comprises a framework of bars between and around the panels. The invention has particular relevance to the efficiency of such structures at preventing the loss of heat from the interior to the exterior of the rooflight in the region of the kerbs at which the glazing is joined to the walls of a building or other substrate.

Background of the invention

A typical prior art rooflight is shown in Figure 1. It has the form of two inclined roof surfaces 3 that meet at a ridge 2, with the ends of the rooflight being closed by vertical gables 4. Alternatively, the end surfaces may also be inclined to form a hipped rooflight. Each surface is formed from planar glazing panels 6 separated by glazing bars 8. The whole structure rests on a kerb 10, which connects it to the building below (not shown). It is also known in the prior art for the rooflight to incorporate a further circuit of vertical glazing between the pitched roof and the kerb 10 to form a lantern structure similar to that shown in the illustration of the present invention in Figure 10.

It is desirable for reasons of energy efficiency to minimize the loss of heat energy from the heated interior of the rooflight to the unheated exterior. Building regulations specify a maximum rate of energy loss per area of rooflight as a U-value, for example 2.0 W/m2K. Minimizing heat loss is also desirable because areas from which heat is lost create cold spots on interior of the rooflight, where condensation is likely to form.

Condensation can obscure the transparency of the glazing, discolour or damage the framework of the rooflight and drip into the building below.

Figure 2 shows in cross section one of the glazing bars 8 between two glazing panels 6. The glazing panels 6 may comprise multi- wall polycarbonate as shown in Figure 2; double-or triple-glazed units with cavities formed between glass sheets; or other insulating panels known in the prior art. By such means, heat loss through the panels 6 themselves can be kept acceptably low.

The glazing bar 8 can be made as an inner part 12 and an outer part 13, which are typically formed as aluminium extrusions. As shown, the inner and outer parts 12,13 do not touch one another so there is a "thermal break" that prevents conduction of heat through the glazing bar 8 from the interior 14 to the exterior 15 of the building.

A spacer (not shown in the drawings) can be placed along the length of the bar 8 between its inner and outer parts 12,13 and can be made of a thermally insulating material such that the thermal efficiency of the bar 8 remains comparable to that of the glazing panels 6. Screws 16 are placed at intervals along the glazing bar 8 to hold is the inner and outer parts 12,13 together but thermal conduction through the screws 16 is negligible. A cover strip 17 may hide the heads of the screws 16 from the exterior for cosmetic purposes.

Figure 3 shows how the inclined glazing panels 6 are supported by the kerb 10 of the rooflight on top of a wall 18 of the building. The kerb 10 comprises a base member and a clamping plate 21, which are formed as aluminium extrusions and fixed together by rivets 22 at intervals along their length. The base member 20 has a support flange 24 that carries a seal 25 for supporting the inner surface of the glazing panel 6. The clamping plate 21 has a corresponding support flange 26 that carries a seal 27 for supporting the outer surface of the glazing panel 6. The clamping plate 21 is visible from the exterior 15 of the building so may be shaped in an aesthetically pleasing manner.

Figure 4 shows how the glazing bars 8 that extend between the angled glazing panels 6 are supported by the kerb 10. At these locations the support flanges 24,26 of the base member 20 and the clamping plate 21 are cut away. The inner part 12 of the glazing bar 8 is secured to the remaining portion of the base member 20 by screws 28 and the glazing bar 8 protrudes through the cut-away portion of the clamping plate 21 to the exterior 15 of the building.

It will be seen from Figure 3 that a protective flange 30 of the base member 20 extends down the outside of the wall 18 to prevent the ingress of moisture beneath the kerb 10. The protective flange 30 is thereby exposed to the exterior 15 of the building and the inner kerb part 20 provides a direct path for the conduction of heat from the interior 14 to the exterior 15. Moreover, the base member 20 is in direct contact with the clamping plate 21, which is in turn exposed to the exterior 15 of the building. As aluminium is highly conductive to heat, the inner kerb part thus remains close to the exterior temperature and forms a cold spot around the interior of the rooflight close to the kerb 10.

As already noted in connection with Figure 4, the inner part 12 of the glazing bar 8 protrudes to the exterior 15 of the building, and it is also in direct contact with the cold base member 20 of the kerb. Thus cold spots also form along the inner parts of the glazing bars 12 close to the kerb 10. These cold spots can lead to condensation around the interior of the rooflight. The base member 20 may be formed with a lip 32 to catch drips in this region but that is not an entirely satisfactory solution because the lip 32 may not catch all the drips, it may also trap dirt and dead insects, and it may look unsightly from inside the rooflight.

Figure 5 shows how the vertical glazing panels 6 in gable ends 4 of the rooflight may be supported by the kerb 10 in the same prior art system. The kerb 10 comprises the same base member 20 as previously described, although its support flange 24 no longer supports the glazing panel 6. Instead of the clamping plate there are riveted to the base member 20 first and second extrusions 34,35 between which the vertical glazing panel 6 is clamped and thereby supported. At locations where a vertical glazing bar extends between the glazing panels (not shown in the drawings), the first and second extrusions 34,35 are omitted entirely and the glazing bar is bolted directly to the vertical face of the base member 20. It will readily be understood that this arrangement suffers from the same problems of heat loss as described in relation to Figures 3 and 4. Moreover, the prominent but support flange 24 of the base member 20, which is redundant in this configuration, reduces the aesthetic appearance of the kerb 10 from inside the rooflight.

Summary of the invention

In a first aspect, the invention provides a glazing support structure for a rooflight as defined in claim I. Preferred features of this glazing support structure are defined in claims 2 to 10.

Because both the glazing bars and the kerb are thermally broken, and because the ends of the glazing bars are enclosed by the kerb, conduction of heat from the interior to the exterior of the rooflight is inhibited and the rooflight is thermally efficient.

In a second aspect, the invention provides a glazing support structure for a rooflight as defined in claim 11. Preferred features of this glazing support structure are defined in claims 12 to 25.

By using a separately formed support member to support the glazing panel, different support members can be provided for use in different configurations of glazing, while a common component can be used for the kerb. This leads to efficiencies in manufacturing and distribution, while allowing the kerb to maintain an attractive appearance that is not spoiled by redundant support elements in certain configurations.

The drawings Figure 1 is a perspective view of a typical rooflight according to the prior au.

Figure 2 is a cross section through a glazing bar of a rooflight according to the prior art, taken on line A-A of Figure 1.

Figure 3 is a vertical section showing the support of an inclined glazing panel at the 3° kerb of a rooflight according to the prior art, taken on line B-B of Figure 1.

Figure 4 is a vertical section showing the support of an inclined glazing bar at the kerb of a rooflight according to the prior art, taken on line C-C of Figure 1.

Figure 5 is a vertical section showing the support of a vertical glazing panel at the kerb of a rooflight according to the prior art, taken on line D-D of Figure 1.

Figure 6 is a perspective view of a gable-ended rooflight according to the present invention.

Figure 7 is a vertical section showing the support of an inclined glazing panel at the kerb of a rooflight according to the present invention, taken on line E-E of Figure 6.

Figure 8 is a vertical section showing the support of an inclined glazing bar at the kerb of a rooflight according to the present invention, taken on line F-F of Figure 6.

Figure 9 is a vertical section showing the support of a vertical glazing panel at the kerb of a rooflight according to the present invention, taken on line G-G of Figure 6.

Figure 10 is a perspective view of a lantern rooflight according to the present invention.

Figure 11 is a vertical section showing the support of a vertical glazing panel at the kerb of a lantern rooflight according to the present invention, taken on line H-H of Figure 10.

For the sake of clarity, the sectional views in Figures 3, 4, 5, 7 and 8 do not show background features lying behind the plane of the section.

Description of preferred embodiments of the invention Figure 6 illustrates a rooflight that incorporates a glazing support structure according to the present invention. The general layout is similar to that shown in Figure 1, with two inclined roof surfaces 3 that meet at a ridge 2 and the ends of the rooflight being closed by vertical gables 4. Each surface is formed from planar glazing panels 6 separated by glazing bars 8. The cross section of the glazing bars 8 may be the same as that shown in Figure 2. Again, the whole structure rests on a kerb 10 but the construction of the kerb 10 differs from the prior art and forms the subject of the present invention. One feature of the invention that may be seen in Figure 6 is that the lower ends of the glazing bars 8 disappear inside the kerb 10 and are enclosed by it to shield them from the exterior atmosphere.

Figure 7 shows how an inclined glazing panel 6 is supported by a kerb 10 according to the present invention. The base member 38 of the kerb 10 comprises an inner portion 40 and an outer portion 41. Between the inner and outer portions 40,41 is a thermal break formed from a material that has low thermal conductivity. In the illustrated embodiment, the thermal break comprises two strips 42 of polyamide, each of which forms a bridge between the inner and outer portions 40,41 of the face member and is arranged with its flat faces face generally parallel to the flat lower surface 43 of the base member 38. The respective edges of each strip interlock with the inner and outer portions 40,41 so that the base member 38 can be handled as a single unit. Preferably the aluminium inner and outer portions 40,4 1 and the polyamide strips 42 of the thermal break are formed together as a co-extrusion. It will readily be understood that the thermal break could be formed as a single strip 42 or as more than two such strips or as a block or as another configuration entirely. Non-conductive materials other than polyamide are also possible constituents of the thermal break.

The surface 44 of the inner portion 40 of the base member 38 that faces into the interior 14 of the rooflight is formed to be smooth in appearance and highly inclined, thus it is pleasing to the eye and unlikely to trap dust or dirt. An upper surface 46 of the inner portion 40 of the base member 38 is inclined to match the incline of the glazing panel 6 and is used to support the glazing bars 8, as described in relation to Figure 8 below. A deep channel 48 is formed in the upper surface 46, which extends along the length of the kerb 10.

A support member 50 is formed as a separate extrusion and has a downwardly projecting bar 52 along its length, which fits snugly into the channel 48 of the base member 38, with a lower surface of the support member 50 resting on the upper surface 46 of the base member 38. The weight of the support member 50 and of the glazing 6 that is supported by it holds the bar 52 in place in the channel 48, while the engagement between the bar 52 and the channel 48 prevents relative transverse movement. A support surface 54 of the support member 50 carries a first sealing strip 56, upon which rests the inner surface of a glazing panel 6. Extending from a lower edge of the support member 50 is a flange 58, which supports the lower end of the glazing panel 6 and prevents the unit from sliding down the incline of the rooflight.

The outer portion 41 of the base member 38 ends in a vertical plate 60, a lower part of which descends below the lower surface 43 of the base member to form a protective flange 62. As in the prior art, that protective flange 62 lies against an outer surface of the wall (not shown in the drawing) to prevent the ingress of water beneath the kerb 10.

A clamping member 64 is riveted to an upper part of the vertical plate 60 of the outer portion 41 of the base member 38. The clamping plate 64 comprises a fascia 66 that may be curved or otherwise shaped to present an attractive external appearance of the kerb 10 and may include a cover strip 68 to hide the heads of the rivets 70 from view.

The clamping plate 64 further comprises a securing flange 72 that engages behind the vertical plate 60 of the base member 38; and a sealing flange 74 that extends rearwards over the lower edge of the glazing panel 6. The sealing flange 74 carries a clasp 76 in which a second sealing strip 78 can be mounted. As may be seen in Figure 7, the clasp 76 has a plane of mirror symmetry 80, whereby the second sealing strip 78 can be mounted in either of two orientations. However, the second sealing strip 78 is not symmetrical about that plane 80 so the two orientations are not equivalent and can be used to seal against glazing panels 6 at two different angles, e.g. inclined and vertical. In the orientation of the second sealing strip 78 shown in Figure 7, the sealing strip 78 conforms to the outer surface of the inclined glazing panel 6. In practice, the plane of symmetry 80 of the clasp 76 has to bisect the angle between the two different orientations of the glazing panels 6.

Between each adjacent pair of glazing panels 6 runs a glazing bar 8. Figure 8 shows how an inclined glazing bar 8 running between a pair of inclined glazing panels 6 is supported by a kerb 10 according to the present invention. Each glazing bar 8 preferably has the same cross section as shown in Figure 2; and the glazing bar that appears in Figure 8 is one of the glazing bars of Figure 2 shown in vertical section on its centreline. In particular, each glazing bar is thermally broken between an inner part 12 and an outer part 13. As previously described, a spacer of a thermally insulating material may be placed along the length of the bar 8 between its inner and outer parts 12,13 but this is not shown in the drawings.

The base member 38 and the clamping plate 64 of the kerb 10 extend continuously along the lower edge of the rooflight. (Naturally, this does not preclude joining multiple lengths end-to-end in a known manner if they exceed the maximum length that is practical for manufacture, transport or handling.) However, the length of the support member 50 is no greater than the width of a single glazing panel 6 so that it does not extend beyond the edges of the glazing panel 6 and does not interfere with the passage of the glazing bars 8. Accordingly, no support member 50 is seen in Figure 8 and the channel 48 of the base member 38 is empty.

The inner part 12 of the glazing bar 8 rests on the inclined upper surface 46 of the base member 38. The lower end of the outer part 13 of the glazing bar 8 rests on the sealing flange 74 of the clamping plate 64. As shown, the lower end of the outer part 13 of the glazing bar may be cut obliquely to lie flush with the upper surface of the sealing flange 74. It will be noted that the second sealing strip need not be mounted in the clasp 76 at the locations of the glazing bars 8.

It will now be explained how the kerb 10 shown in Figures 7 and 8 is fully thermally broken. The thermal break is marked with a dash-dot-dot line 82. Considering first Figure 7, the glazing panel 6 is inherently of low thermal conductivity from the inner face to the outer face and in the example shown has a void 84 running the length thereof. The void is closed by an end wall 86, which is generally of a low conductivity material. The kerb 10 is thermally broken between the inner and outer portions 40,4 1 of the base member 38 and the configuration is such that only the inner portion 40 and the support member 50 are in contact with the inner surface of the glazing panel 6, while only the clamping plate 64 is in contact with the outer surface of the glazing panel 6. Accordingly, the inner portion 40, the support member 50 and the inner surface of the glazing panel 6 remain substantially at the temperature of the interior 14 while the outer portion 41, the clamping plate 64 and the outer surface of the glazing panel 6 remain substantially at the temperature of the exterior 15.

Considering Figure 8, the glazing bar 8 is thermally broken between its inner part 12 arid its outer part 13. The kerb 10 is thermally broken as previously described.

Accordingly, the inner portion 40 and the inner part 12 of the glazing bar 8 remain substantially at the temperature of the interior 14 while the outer portion 41, the clamping plate 64 and the outer part 13 of the glazing bar 8 remain substantially at the temperature of the exterior 15. Moreover, unlike the prior art, the lower end of the inner part 12 of the glazing bar 8 is enclosed in a longitudinal chamber 88 formed by the base member 38 and the clamping plate 64. The chamber 88 prevents the flow of air from the exterior 15 over the inner part 12 of the glazing bar, which would risk cooling it.

Figure 9 shows how the vertical glazing panels 6 in gable ends 4 of the rooflight may be supported by the kerb 10 according to the invention. The base member 38 and the clamping plate 64 of the kerb 10 are identical to those shown in Figures 7 and 8.

Accordingly, for each component only a single type of extrusion needs to be manufactured, stocked and distributed.

For this configuration a different support member 50a is provided. The support member 50a for vertical glazing panels 6 again has a downwardly extending, longitudinal bar 52, which is fitted into the channel 48 in the upper surface 46 of the base member 38, and the support member 50a bears on the upper surface 46 of the base member 38. A support flange 58a extending from a lower edge of the support member 50a provides a horizontal surface on which the end wall 86 of the glazing panel 6 can rest. The body of the support member 50a carries a first sealing strip 56 that is vertically oriented to seal against the inner surface of the vertically oriented glazing panel 6. The first sealing strip 56 is of the same kind as is used for inclined glazing. The clamping plate 64 carries a second sealing strip 78 that is vertically oriented to seal against the outer surface of the vertically oriented glazing panel 6.

The second sealing strip 78 is of the same kind as is used for inclined glazing but in -10-this configuration it is inserted in the clasp 76 of the clamping plate 64 with the opposite orientation.

Figure 9 also shows, behind the plane of the drawing, a vertically oriented glazing bar 8. The glazing bar 8 is of the same kind used for inclined glazing. The support member 50a for vertical glazing provides a horizontal upper surface 90 upon which the lower end of the inner part 12 of the glazing bar 8 can bear. The support member SOa also provides a vertical flange 92, against which the inner face of the inner part 12 of the glazing bar 8 is located. The end of the outer part 13 of the glazing bar 8 is cut off at an appropriate angle to lie flush against the upper surface of the sealing flange 74 of the clamping plate 64, as before.

As with inclined glazing, there is a thermal break along line 82 in this configuration so that the inner part of each component does not make thermal contact with the outer part or with the exterior air 15.

Figure 10 shows an alternative form of rooflight constructed using the system of the present invention. In this "lantern" form, the upper section has the structure of a hipped roof, its sides being formed by two runs 3 of inclined glazing panels 6 that meet at a ridge 2; and its ends being formed by two triangular areas of glazing 5 at the same angle of inclination. Below the roof section is a circuit of vertical glazing panels 6 forming a glazing wall 7. We shall refer to the junction between the glazing wall 7 and the wall of the building below (not illustrated) as the lower kerb 1 Oa; and the junction between the glazing wall 7 and the inclined glazing 3,5 as the upper kerb * 25 lOb. A vertical section through the glazing wall 7 is shown in Figure 11.

Because the glazing wall 7 has to support the entire weight -including the lateral thrust -of the rooflight above it, its glazing support structure needs to be stronger than in the case of the simple gable end 4 of Figure 6. Just beneath the upper kerb lOb, the glazing wall 7 is encircled by a ring beam 94 to contain the lateral thrust from the roof. The ring beam 94 has a box section for strength, as seen in Figure 11. The glazing bars 8 of the glazing wall 7 have a reinforced inner part 96, also with a box section (not visible in the drawings), to support the vertical load from the roof.

The base member 38 and the clamping plate 64 of the lower kerb lOa are identical to those shown in Figures 7, 8 and 9. Once again, in this situation, only a different support member SOb needs to be provided. The reinforced support member 50b is very similar to the support member for vertical glazing 50a shown in Figure 9 but it has a greater width in order to accommodate the greater load that it has to bear. Thus the upper surface 90 is equal in width to the reinforced glazing bar 96. As a result of its greater width, the reinforced support member 50b rests not only on the upper surface 46 of the base member 38 but also on the inclined inwards-facing surface 44 of the base member 38. Nevertheless, viewed from the interior 14, the kerb lOb still presents a clean and attractive appearance. In other respects, the lower kerb I Oa is the same as the kerbs previously described and that description will not be repeated.

The base member 38 and the clamping plate 64 of the upper kerb lOb are identical to those shown in Figures 7, 8 and 9. The support member 50 for the inclined glazing is identical to that shown in Figure 7. The only difference from the kerb 10 of Figure 7 is that the upper kerb lOb rests on top of the ring beam 94 instead of a masonry wall of the building. It is secured to the ring beam 94 by bolts 97 through the base of the channel 48. It will be noticed that the bar 52 of the support member 50 does not fill the base of the channel, in order to leave a gap that can accommodate the heads of the bolts 97. A clip 98 may be engaged with the outer portion 41 of the base member, behind the protective flange 62, to support and seal against the top of the vertical glazing panel 6. -12-

Claims

I. A glazing support structure for a rooflight, comprising: a kerb structure extending along a lower edge of the rooflight for anchoring the rooflight to a substrate, the kerb structure comprising an inner portion, an outer portion and a thermal break between the inner and outer portions; and glazing bars for arrangement between adjacent glazing panels, each glazing bar comprising an inner portion, an outer portion and a thermal break between the inner and outer portions; the inner portion of the kerb structure having means for supporting an inner surface of a glazing panel and means for supporting the inner portions of the glazing bars; the outer portion of the kerb structure having means for sealing against an outer surface of a glazing panel; and the kerb structure enclosing the lower ends of the glazing bars.
2. A glazing support structure according to claim 1, wherein the thermal break of the kerb structure comprises two parallel strips of thermally insulating material.
3. A glazing support structure according to claim 2, wherein the kerb structure has a generally flat base and wherein the two strips are generally parallel to the base.
4. A glazing support structure according to any preceding claim, wherein the thermal break of the kerb structure comprises a polyamide material.
5. A glazing support structure according to any preceding claim, wherein the thermal break of the kerb structure is a co-extrusion with at least part of the inner portion and at least part of the outer portion of the kerb structure.
6. A glazing support structure according to any preceding claim, wherein the outer portion of the kerb structure comprises an outer kerb and a clamping plate attached to the outer kerb, the means for sealing against an outer surface of a glazing panel being mounted on the clamping plate.

-13 -
7. A glazing support structure according to claim 6, wherein the sealing means is mounted reversibly on the clamping plate and is shaped so that by reversing the sealing means it can seal against glazing panels having either of two orientations.
8. A glazing support structure according to any preceding claim, wherein the inner portion of the kerb structure comprises an inner kerb and a support member that is formed separately from the inner kerb, the means for supporting an inner surface of a glazing panel being provided by the support member.
9. A glazing support structure according to any preceding claim, wherein the support member further comprises means for supporting an end wall of a glazing panel.
10. A glazing support structure according to claim 8 or claim 9, wherein the means for supporting the inner portions of the glazing bars is provided by the inner kerb.
11. A glazing support structure for a rooflight, comprising: a kerb base extending along a lower edge of the rooflight for anchoring the rooflight to a substrate; and a support member formed separately from the kerb base, extending along the kerb base and engaged with the kerb base, the support member having means for supporting a lower edge of a glazing panel.
12. A glazing support structure according to claim 11, wherein each of the kerb base and the support member is formed as an extrusion.
13. A glazing support structure according to claim 11 or claim 12, wherein the support member interlocks with the kerb base.
14. A glazing support structure according to claim 13, wherein the kerb base comprises a channel and the support member comprises a protrusion that rests in the channel.
15. A glazing support structure according to any of claims 11 to 14, wherein the means for supporting a lower edge of the glazing panel is a flange that extends laterally from the support member and is oriented to abut an end wall of the glazing panel.
16. A glazing support structure according to any of claims 11 to 15, comprising more than one type of support member for use with a single type of kerb base.
17. A glazing support structure according to claim 16, wherein different types of support member have means for supporting the glazing panel at different orientations with respect to the kerb base.
18. A glazing support structure according to claim 17, wherein the kerb base has a generally flat underside and wherein one of the types of support member has means for supporting the glazing panel generally perpendicular to the underside of the kerb.
19. A glazing support structure according to claim 17, wherein the kerb base has a generally flat underside and wherein one of the types of support member has means for supporting the glazing panel at an acute angle with respect to the underside of the kerb base.
20. A glazing support structure according to claim 19, wherein the acute angle is in the range 200 to 450
21. A glazing support structure according to any of claims 16 to 20, wherein different types of support member are designed to support different amounts of load. -15-
22. A glazing support structure according to claim 21, wherein types of support member designed to support greater amounts of load have a greater area of contact with the kerb base.
23. A glazing support structure according to any of claims 11 to 22, further comprising a clamping plate formed separately from the kerb base, extending along the kerb base and engaged with the kerb base, the clamping plate having means for sealing against an outer surface of a glazing panel supported by the support member.
24. A glazing support structure according to claim 23, wherein the sealing means is mounted reversibly on the clamping plate and is shaped so that by reversing the sealing means it can seal against glazing panels supported by the support member in either of two orientations.
25. A glazing support structure according to any preceding claim, further comprising a glazing panel supported by the support member, wherein the support member has a longitudinal dimension less than the dimension of the glazing panel measured along the same direction, whereby the ends of the support member do not extend beyond the glazing panel.
26. A glazing support structure substantially as described herein with reference to Figures 6 to 11.