GB2399380A

GB2399380A - Thermally efficient glazing unit

Info

Publication number: GB2399380A
Application number: GB0411727A
Authority: GB
Inventors: Robin Jeffrey; Christopher Avery
Original assignee: Hambleside Danelaw Ltd
Current assignee: Hambleside Danelaw Ltd
Priority date: 2001-08-21
Filing date: 2002-08-21
Publication date: 2004-09-15
Anticipated expiration: 2022-08-21
Also published as: GB2399380B; GB0411727D0

Abstract

A roof light or skylight assembly 10 comprises a pair of translucent or transparent panels 12, 14, secured together and shaped to define a cavity between the panels 12, 14. The cavity accommodates insulating means 16 comprising light transmitting components in the form of tubes 18. The tubes 18 are oriented parallel to the panels 12, 14. A major surface of the insulating means 16 is spaced from both panels 12 and 14. The glazing unit may be provided with spacing means between one of the panels 12, 14 and the insulating means 16 to define a cavity. A translucent capping sheet may be disposed between the insulating means 16 and the cavity.

Description

THERMALLY 13 F9IClENT GLAZIN(i; UNU The present invention relates to a

glazing unit for a roofllght, skylight, walllight or northlight, which is thermally efficient whilst maintaining a desirable level of light transmltance to achieve translucency or transparency in the topflight Rooflights are used simply to increase the level of natural light into a building! thus reducing artificial lighting costs and being environmentally friendly insofar as He necessary electricity consumption is reduced Further, it is recognized that sustained exposure to artificial lighting may not be beneficial fi.om a health point of view; to increase the amount of natural light available to a building, thereby reducing the necessary amount of artificial light needed. may impart health benefits However, these benefits of rooflight installation are oRen offset against the potential Josses, economic and environmcutal, due to the thermal ineff'cicacy of such rooflights.

It is known to manufacture roofllghts front thermosening material' for example GRP, by means of a single or double layer of such,naterial Strength has in the past been considered the primary requirement for such a product.

However, Building Regulation 2000, Parts L, and E issued by the DETR of United Kingdom, which came into force in April 2002 are to demand specific thermal efficiency standards of construction components, demanding a Thorrnal transmimuce or U value of at least 22 W.rn 2K' for rooflights. The current method within the rooflight production industry is to insert a third layer of thermosetting material between the inner and outer panels of a two ply rooflight. Using this configuration, a lower U value may be achieved. This is still not a particularly satisfactory wl'tioD, as a disorepancy in the thermal efficiency of such a rooGight would render it unacceptable and its performance is borderline at 2.2 W.m9K Ink leaving little scope to meet future proposed regulations.

Some solutions to this thermal energy loss problem have been proposed; oRen these are not economically viable, as they are overly complex and/or comprise expensive materials. In some cases! the materials used to increase the thermal efficiency of He apparatus may result in reduced light transmittance through the rooflight as a whole, thereby impairing its primal function. t

The invention disclosed herein presents a solution, which welts to solve, or at least mitigate' the problems associated with the prior art in a practical and cost effective way One aspect of the invention provides a glazing unit comprising a pair of translucent or transparent panels secured together Ad shaped to define a cavity between the panels which cavity is adapted to accommodate insulating means. The insulating mean" comprising a plurality of light transnnitting tubiform components.

The current invention presents a solution vvhich not onlyyields lower U values, but which can be adapted by changing simply the number of layers or thickness of the insulating means, so as to achieve variable levels of insulation effect.

Preferably, the tubiform components are provided with tubes having partially reflective walls to enhance the light transmission through the glazing unit. Optionally the tubiform component may comprise tessellating tubes.

More preferably, the tubiform components are arranged in rows, adjacent rows are offset from each other so that each tessellating tube of a first row nests between adjacent tessellating tubes of a second row.

In some embodiments, the rows of tubiform components are oriented substantially perpendicular with respect to the pair of panels.

Optionally, the tubiform components arc circular in cross section and are disposed parallel with respect to the pair of panels The tubiform components in this embodiment are arranged in rows, adjacent the rows being offset by a distance of half the diameter of each prismatic component.

According to another optional feature of this aspect of the invention, the tubiform components are arranged in rows, each subsequent rove of prismatic components being set in a configuration substantially perpendicular to the adjacent row or rows. i r

According to another optional feature of this aspect ofthe invention the insulating means may be constructed whorl' or prlucpally of transparent or translucent plastics materials.

Preferably the transparent or translucent plastics materials may be any one of PVO, cellulose acetate, polyester, polyethylene or polypropylene, or indeed any other suitable thermosetting material.

According to yet another optional feature of this aspect of the invention the pair of translucent or transparent panels may be made from thermoseuing materials. Preferably, the pair of translucent or transparent panels may be made from Glass Reinforced Polyester.

There may farther comprise spacing means so arranged as to define a cavity between the insulating means and one of the transparent or translucent panels. Preferably the spacing means may be resiliently biased to exert pressure onto a surface ofthe insulating means. so as to restrict movement of the insulating means In one class of embodiments, there may comprise a capping sheet mounted to a surface of the insulating means Preferably, the capping sheet is translucent. Optionally, the capping sheet is constructed of a thertnosetting material such as aGRI.

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Optionally, the capping sheet covers the entire area of at least one surface of one or more portions of the insulating means.

An alternative feature of the current aspect of the present invention provides that the capping sheet may tenninate short of a end edge of the insulating means to defines border region of the insulatug means having engagement means for engaging an edge of the glazing unit.

Preferably the cngazement noons may be provided by the border region which is compressible so as to engage an edge of the glazing unit.

A further alternative feature provides the' the capping sheet protrudes outwardly beyond at least one edge of a portion of the insulating means to overlap the adjacent portion of the insulating means.

A second aspect of the present invention provides a glazing unit comprising a pair of translucent or transparent panels secured together and shaped to define a space between the .: ' 1 ' ., ' ' tubiform insulation components, which glazing unit further comprises spacing means between one of the translucent or transparent panels, and the insulating means, the spacing means defining a further cavity between the one of translucent or transparent panels and the insulating means, to provide an airtight environment. Is

A third aspect of the invention provides a rooflight comprising a glazing unit, an upper mounting means for mounting the glazing unit to a roof; wherein the glazing unit comprises an upper panel and a lower panel secured together in a spaced arrangement to define a void between the upper and lower panels7 which void accommodates insulating means, the I n insulating means comprising a plurality of prismatic components adapted for retaining air and its thermal energy.

Exemplary embodiments will now be described by way of example only, with reference to the accompanying drawings, in which: FIGURE I is a perspective view of a rooflight apparatus as according to one aspect of the present invention; _ FIGURE 2 is a cutaway perspective view of a rooflight apparatus, showing the arrangement ofthe insulating means therein, as according to one embodiment ofthe present invention; FIGURE 3 is a further cutaway perspective vie v of a rooflight apparatus as according to a second embodiment of the present invention; FIGURE 4 is a cutaway perspective view of a rooflight apparatus as according to Figure 3, showing an alternative arrangement of the insulating means Herein; FIGURE 5 is a cutaway perspective view of a rooflight apparatus including insulation means as in Figure 3, showing a further alternative configuration of said insulation means, FIGURE 6 is a side view of part of a rooflight apparatus according to a fourth embodiment of the present invention; :; : FIGURE HA is a side view showing the construction of A capping sheet 140 as according toe further embodiment of the present invention; FIGURE 7B is a side view showing a capping sheet 140, as shown in Figure7A, in operation within a rooflight unit; and FIGURE g is a perspective view of two portions of insulating means according to a furthct optional feature of the present invention.

According to a preferred embodiment of the present invention there is shown in the drawings in particular Figures 2, 3, 4 and 5 a glazing unit comprising a pair of translucent or transparent panels secured together and shaped to define a cavity between the said panels, which cavity is adapted to accommodate insulating means, said insulating means comprising a plurality of light transmitting tabiform components.

The glazing unit is adapted to form part of a rooflight assembly, and can be manufactured in situ or supplied as a sealed unit.

_ in Figures I and 2, the glazing unit I O comprises a pair of panels, respectively the inner panel 14 and the outer panel 12, formed so as to allow the formation of a cavity 20 between the inner and outer panels 14 and 12 This cavity 20 accommodates insulation means 16; the insulation means 16 is so constructed and arranged AS to maintain the light transmittance of Me rooflight apparatus I O whilst reducing the loss of thermal energy therefrom.

The insulating means 16 comprises a layer of tubiform components 22, constructed of a transparent or translucent plastics material, for example PVC, polythene, cellulose acetate, polyester or polypropylene. The tubifonn components are light transmitting and are preferably provided with one or more walls that are partially reflective so as to enhance the transmissibility.

In the embodiment in Figure 2 the tubiform components 22 are vertically disposed with respect to the inner and outer panels 12, 14, therefore being generally pepondiealar thereto.

These tubiform components 22 are preferably interconnected in the form of transparent or translucent sheeting, for example as shown in Figure 8. The nature of such components22 is advantageous in that it allows easy cutting of such insulating material to a desired size. This therefore would allow for the insulating aerial to be cut in situ, and the roofllght 10 to be Filly assembled on-site. Furthermore, it can be fitted on a retrofit basis. Alematively, the ease of sizing and shaping insulating material which is constructed in this way allows the material to be cut, and the rooflight to be pre-assembled.

In Figure 2. the tubiform components 22 may comprise a "honeycomb" of tubes (or prisms).

Preferably, the tubes are tessellating and may adopt the general form of any tessellating polyhedron. Preferably, though not limitingly, the tubes are characterized by a constant cross- sectional shape; this cross-sectional shape may be a square, a parallelogram, a triangle, a chevron, or indeed any other two-dimensional shape. The tubes 22 may further be charactcrised by curved or flat planar faces, and may adopt any general form without departing form the scope of the present invóntlorn It is envisaged that the cross sectional shape of the cubes can be altered according to particular manufacturing requirements without departing Tom the scope of invention.

Any of the configurations referred to above increase the light allowed into the building, as it transmits light Rom the sides of the rooflight I O as well as from vertically above Indeed, under testing to regulation no. DIN 5036, light transmittance by a rooflight a cording to the present invention was shown to be improved by 25% with respect to standard tripleskinned glass-reinforced plastics rooflight assemblies. This advantageous aspect arises due to a 'lens 2$ effect' caused by the arrangement of the tubes in the core of the rooflight assembly.

Despite this increased transmittance of desirable light, however, another benefit of this aspect of the present invention lies in the fact Mat the rooflight offers protection against harmful ultraviolet light by the introduction of a W inhibitor into the composition of the tubiform components. By varying the composition of the insulating means 16, the insulating means provides further protection fiom infrared light. By adding substances of a tinted nature, for example, to the composition of the insulating means 16, & coloured roofllght may be produced; by an analogous addition' the solar gain can be reduced, thus restricting the thoroughflow of undesirable fractions of light, such as light in the infrared region. To adopt the specific example of light in the inhered region, the reduction of such light can reduce the heat gain in a building that may otherwise result from solar radiation onto the building.

Additives to the composition of the insulating means 16 to coat the internal surface of the tubiform components to impart the properties of an optical brightener to the roofliEht.

augmenting the light-flow therethrough by improving the reflective characteristics.

In a second embodiment of the present invention shown in Figure 3, each tubiforn component 18 adopts a circular crossection, and has a generally cylindrical forth lithe rubiform components 18 may adopt the form of a single insulating sheet acomrnodatod within the cavity 20 of the rooflight 10. Again, such a sheet may be formed from any suitable plastics material. The ease of assembly and other advantageous characteristics relating to shaping and sizing of insulation material, as described above. also apply to this embodiment.

According to a third embodiment, the insulating means 16 may optionally further comprise two or more such layers of tubiform components 18, 22 oriented in a plane substantially parallel to the pair of panels. The use of a plurality of layers of insulating material fonned by the tubiforrn components 18, 29 adds greater insulating effect. Indeed, using the two layers of such components may reduce the U value to 1.5, whilst a third layer may reduce it to 1.4.

Additionally or alternatively, the thickness of each layer of tubes 22 may be increased.

Two examples of insulating means are shown in Figures 3 and 4. Figure 3 illustrates three layers of nbiform components I B and Figure 4 shows five layers of tubiform components 18.

These components 18 may, for greater insulating effect, be assembled one on top of the other, each layer set In a configuration substantially perpendicular to the last. This configuration is illustrated in Figure 5 of the accompanying drawings. This "crosshatched" effect lends even greater thermal efficiency to the unit, without impairing either the light transmittance or the ease of assembly In Pigures 3, 4 and 5 each layer is formed by a series of circular tubes 18 although it is envisaged the form of tubes shown in Figure 2 can be used in the orientation of Figures 3 to 5 without departing from me scope of invention. j

Referring again to Figures 3, 4 and 5, the circular tubes 18 may be secilred together by tape or other securing means to form a roll, for ease of handling. In use, rows are fiorrned by unrolling and cutting to the desired length; adjacent rows are offset, as shown in Figures 3 and 4, to improve nesting and therefore the rigidity of the insulating means In some embodiments the insulating means 16 abuts the upper and lower panels 12, 14 to improve rigidity of the structure. Furthermore, the thickness of the tubiform component walls may be varied to increase or, alternatively to decrease the rigidity of the insularlng means.

It should be recognised that the crossectional width of the opening within the insulation means 16, and the depth thereof, are variable without causing departure front the scope of the present invention. Insulation means incorporating openings of a lesser cross sectional width will produce a more "dense" material that acts as a more efficient insulator.

A Further advantage with the present invention, and the preferred embodiment in particular, is that the insulating means forms a bame, which may further act as an effective barrier to sound.

In tests, using an arrangement shown in Figure 2 with a cellulose acetate honeycomb having cells of a cross-sectional width or length of Amp, and a chamber depth (i.e. distance between upper and lover surfaces of said honeycomb insulation means) of 80mm, the U Value is 1.0 W.m 2K-', which is a significant improvement over conventional doublskinned rooflights usually rated in excess of 2.8 W.m.2K '.

A further, fourth, embodiment of the present invention is shown in Figure 6. Again, this embodiment of the present invention is similar to the previously described embodiments, and so, only Me distinguishing features of this embodiment will be described in any detail hereafter. Like reference numerals are used as in previous embodiments, but with the prefix "1" ascribed thereto. The rooflight 110 according to this fourth embodiment of the present invention is provided with spacing means 130 between one of said translucent or transparent pancis 112, 114 and said insulating means 116. The spacing means 130 may further augment the insulating capability of the rooflight 1 10' by defining a cavity C within said rooflight I 10, thereby creating an airtight environment. lo l

In this embodiment, the spacing means is provided by a pair of upstanding wall portions 131 133 hinged together at an apex 135 Preferably, the wall portions 131, 133 arc constructed of a resilient but flexible material, for example GRP The apex 135 abuts the upper wall panel 112 so as to apply a downward pressure to a surface of said insulating means 1 16, thereby holding the insulating means 1 16 in place without the need for any adhesive or other known secorlng means to be applied thereto According to a fifth embodiment of the present invention, there is provided a capping sheet on a surface ofthe insulating means 116 shown in Figures 6, 7A and 7B According to a further optional feature shown in Figures 7A and 7B, the capping sheet 140 is disposed between a surface ofthe insulating means l 16, and the cavity C defined bythe spacing means 130 This embodiment of the present invention is shown in Figures 7A and 7B In one class of embodiments, the unit is of a sealed construction by being formed visits close tolerance profile definition for example of the type shown in Figure 7 Thus, the unit is made _ substantially airtight, clearly ameliorating the insulating performance of the unit Also, the materiels used in the manufacture of the rooflight according to this preferred embodiment impart no noticeable extra mass to the unit; indeed, the mass of such a unit is largely similar to that of a standard known triple-skinned assembly. Accordingly, no change in working practices for the use of the units according to the present invention is necessary It is envisaged that the capping sheet 140 may be constructed of a thermosetting material for example a glassreinforced plastics material, or a glass fibre tnaterial. In the embodiment of Figures 7A and 7El, the capping sheet 140 is so constructed and arranged about the insulating means 116 as to seal said insulating means 116 in plate within the rooflight 110. In Figure 7El, the capping sheet is provided with an upstanding portion 14] for securing to the lower wall panel 114 and a protruding portion 143, to be placed intermediate the upper and lower wall panels 112, 1 14 to be secured thereto l All of these embodiments of the present invention may be adapted for assembly at the point of installation' or may be supplied in a reedy assembled form for simple installation of the rooflight unit Some embodiments are provided with a capping sheet 140 vvhoe area runs short of one or rive first edges of each portion of the insulating means) l6. but whose area extends beyond the edge or edges of the insulating meant 116 which are opposite to the said one or two first edges Accordingly, a series of interconnected portions of insulating means 116 may be adopted, wherein each portion of insulating means l i 6 is partially overlaid by the protruding I O part of the capping sheet 140 of the last portion of the insulating means 1 16. Insulating means tl6, provided with a capping sheet 140 according to this aspect of the present invention is shown in Figure 8.

Idle capping sheet 140 may be of a slightly lesser area than the insulating means 116, as shown in Figure 8. Therefore, there is provided a border region A, B of the insulating means 116 that shows around the edges of the capping sheet 140. Preferably, the insulating means 116 is compressible, such that the insulating means 116 capped by a capping sheetmay flex in a manner sympathetic to the shape of the rooflight 110, thereby to engage an edge of the _ roofligh' by an "interferences' type fit. Alternative cogagemene unmans for securing the insulating means to the rooflight are envisaged, for example adhesive or mechanical fasteners lit is envisaged that the capping sheet 140 be constructed of a thennosetting material such as a plastics material or a glass fibre material. It will be recognized, however, that the composition of capping sheet 140 need not be limited to such substances. All that is required of a material to form the capping sheet 140 is that it be capable of being formed into a thin translucent film; preferably (though not limitingly), the thickness of the capping sheet 140 is in the region of 0.150.80 mm It will be understood that teens of orientation used herein, such as "upper", "inner", "outer"', "horizontal", "vertical" and the like, do not limit their respective components to these configurations, but merely serve to distinguish one component Tom another. It will be further recognized that a variety of different configurations may be used, without departing from the scope of the current invention ! It is envisaged that such a rooflight apparatus may be mounted to a roof by mechanical fixings or other suitable means known in the art. For example, a rooflight can be mechanically fixed by surrounding purlins and profiled sheeting in accordance with traditional methods.

It will be understood that Where GRP material has been given as an exemplary construction material, any other transparent or translucent material suitable for the purpose may be substituted therefor, without departing from the scope of the invention.

Further, whilst hereinbefore the application of the present invention has been described as for a rooflight, indeed the present invention may be applied to any glazing, or other means for thermally efficient natural lighting.

Claims

1. A glazing unit comprising a pair of translucent or transparent panels secured together and shaped to define a cavity between the said panels, which cavity is adapted to accommodate insulating means, said insulating means comprising a plurality of light transmitting tubiform components.

2. A glazing unit as claimed in claim 1, wherein said tubiform components are tubes having partially reflective walls to enhance the light transmission through the glazing unit.

3. A glazing unit as claimed in cluing I or claim 2, wherein the tubiform components are tessellating tubes.

4. A glazing unit as claimed in claim 3, wherein the tubiform components are arranged in rows, adjacent rows are offset from each other so that each tessellating tube of a first rove nests between adjacent tessellating tubes of a second row 5. A glazing unit as claimed in claim 4 wherein the rows of tubiform components are -, oriented substantially perpendicular with respect to said pair of panels.

6 A glazing unit as claimed in claim I or claim 2, wherein said tubiform components are circular in cross section and are disposed parallel with respect to the pair of panels.

7. glazing unit as claimed in claim 6 wherein the tubiform components are arranged in rows, adjacent said rows being offset by a distance of half the diameter of each prismatic Component.

8. A glazing unit as claimed in claim 6, wherein the tubiform components are arranged in rows' each subsequent row of prismatic components being set in a configuration substantially perpendicular to the adjacent row or rows.

9. A glazing unit as claimed in any preceding claim, wherein said tubiform components adopt the form of a single insulating sheet. l

10. A glazing unit as claimed in any preceding claim wherein said insulating means is! constructed wholly or principally of transparent or translucentplastics materials.

1 1. A glazing unit as claimed in claim 10 wherein said transparent or translucent plastics materials are any one of PVC Polyester cellulose acetate polyethylene or polypropylene.

12 A glazing unit as claimed in any preceding claim wherein the pair of translucent Or transparent panels is made frond a thennosetting material or thennosetting materials to 13. A glazing unit as claimed in claim 12 wherein the pair of translucent or transparent panels is made from Class Reinforced Polyester.

14. A glazing unit as claimed in any preceding claim wherein there comprises spacing means so arranged as to dense a cavity between said insulating means and one of said I 5 transparent or translucent panels.

15. A glazing unit as claimed in claim 14 wherein said spacing means isresiliently biased to exert pressure onto a surface of said insulating means so as to restrict novemcat of said insulating means.

16. A glazing unit as claimed in any preceding claim wherein there comprises a capping sheet mounted to a surface of said insulating means. I 17. A glazing unit as claimed in claim 16 wherein the capping sheet is translucent.

18. A glazing unit as claimed in claim 16 Or claim 11 wherein the capping sheet is constructed of a thermosening material such as a plastics-based material.

19. A glazing unit as claimed in any of claims 16 to 18 wherein said capping sheet covers the entire area of at least one surface of one or more portions of the insulating means.

A glazing unit as claimed in any of claims 16 to 18 wherein said capping sheet terminates short of an end edge of the insulating means to define a border region of the insulating means having engagement means for encaging an edge of the glazing unit t 21. A glazing unit as claimed in claim 20 Wherein said engagement means is provided by said border region \vhich is compressible so as to engage an edge ofthe glazing unit.

22 A glazing unit as claimed in any of claims 16 to 21, wherein said capping sheet protrudes outwardly beyond at least one edge of a portion of said insulating means to overlap the adjacent portion of said insulating means 23. A glazing unit comprising a pair of translucent or transparent panels secured together and shaped to define a space between the said panels, which space is adapted to accommodat insulating means such as a series of tubiform insulation components, which glazing unit further comprises spacing means between one of said translucent or transparent panels, and said insulating means, said spacing means defining a further caviby between said one of translucent or transparent panels and the insulating means, IO provide an airtight environment.

IS

24. A rooflight comprising a glazing unit, an upper mounting means for mounting the glazing unit to a roof; wherein said glazing unit comprises an upper panel and a lower panel secured together in a spaced arrangement to defies a void between said upper and lower À panels, which void accommodates insulating means, the insulating means comprising a plurality of prismatic components adapted for retaining air and its thermal energy.

25. A rooflight comprising a glazing unit as claimed in any oneofclaims I to 22.

26. A rooflight substantially as hereinbefore described 27. A glazing unit substantially as hereinbefore described.

28. A glazing unit substantially as hereinbefore described with reference to Figures2, 3, 4 or 5 of the accompanying drawings 1; Amendments to the claims have been filed as follows 1. A rooflight or skylight assembly comprising a pair of translucent or transparent panels secured together and shaped to define a cavity between internal surfaces of said panels accommodating insulating means, said insulating means comprising a plurality of light transmitting tubiform components, the tubiform components arranged in the form of one or more layers substantially parallel to the pair of panels, and the upper surface of the insulating means being spaced from the internal surfaces of both panels.

2. An assembly as claimed in claim 1, wherein the tubiform components are arranged in rows.

3. An assembly as claimed in claim 1 or 2, wherein said tubiform components adopt the form of a single insulating sheet.

4. An assembly as claimed in claim 1 or 2 including a plurality of layers of tubiform components.

5. An assembly as claimed in any preceding claim, wherein said tubiform components are tubes having partially reflective walls to enhance the light transmission through the glazing unit.

6. An assembly as claimed in any preceding claim, wherein the tubiform components are tessellating tubes.

7. An assembly as claimed in any preceding claim, wherein said tubiform components are circular in cross section.

8. An assembly as claimed in any preceding claim wherein said insulating means is constructed wholly or principally of transparent or translucent plastics materials.

9. An assembly as claimed in claim 8, wherein said transparent or translucent plastics materials are any one of PVC, Polyester, cellulose acetate, polyethylene or polypropylene.

10. An assembly as claimed in claim 8, wherein the pair of translucent or transparent panels is made from a thermosetting material or thermosetting materials.

11. An assembly as claimed in claim 10, wherein the pair of translucent or transparent S panels is made from Glass Reinforced Polyester.

12. An assembly as claimed in any preceding claim, including spacing means arranged to define a cavity between said insulating means and one of said transparent or translucent panels.

13. An assembly as claimed in claim 12, wherein said spacing means is resiliently biased to exert pressure onto a surface of said insulating means, so as to restrict movement of said insulating means.

14. An assembly as claimed in any preceding claim, including a capping sheet mounted to a surface of said insulating means.

15. An assembly as claimed in claim 14, wherein the capping sheet is translucent.

16. An assembly as claimed in claim 14 or claim 15, wherein the capping sheet is constructed of a thermosetting material such as a plastics-based material.

17. An assembly as claimed in any of claims 14 to 16, wherein said capping sheet covers the entire area of at least one surface of one or more portions of the insulating means.

18. An assembly as claimed in any of claims 14 to 16, wherein said capping sheet terminates short of an end edge of the insulating means to define a border region of the insulating means having engagement means for engaging an edge of the glazing unit.

19. An assembly as claimed in claim 18, wherein said engagement means is provided by said border region which is compressible.

20. An assembly as claimed in any of claims 14 to 19, wherein said capping sheet protrudes outwardly beyond at least one edge of a portion of said insulating means to overlap the adjacent portion of said insulating means.

21. A rooflight or skylight assembly as claimed in any preceding claim substantially as hereinbefore described.

22. A rooflight or skylight assembly substantially as hereinbefore described with reference to and as illustrated in any one of Figures, 3, 4 or S of the accompanying drawings.