WO2008067582A1

WO2008067582A1 - A wall system

Info

Publication number: WO2008067582A1
Application number: PCT/AU2006/001849
Authority: WO
Inventors: Andrew William Close; William Gilbert Poynter
Original assignee: Boral Australian Gypsum Limited
Priority date: 2006-12-06
Filing date: 2006-12-06
Publication date: 2008-06-12

Abstract

A wall system comprising at least two studs, at least one elongate mounting member extending from one to a second of the studs and a layer of cladding material retained by the elongate mounting member(s).

Description

A WALL SYSTEM

TECHNICAL FIELD

The present invention relates to a wall system, more particularly a wall system that is designed to provide fire resistance and/or acoustic isolation. The wall system involves one or more layers of cladding material applied to upright structural elements of the wall, such as studs, using mounting members to support sheets of the cladding material.

BACKGROUND ART

It is well known to secure cladding material such as plasterboard to a wall frame using fasteners. However, in a fire situation the sheets of cladding material can shrink and cause the cladding material either to break away from the fasteners or to pull the fasteners from the wall frame, resulting in early failure of the wall.

The mounting of cladding material to upright structural elements of a wall in other ways is also known. For example, it has been known to secure a length of top-hat section, having a central channel and opposed flanges, between structural elements of a wall using fasteners such as screws or nails, that pass through the central channel of the section. Cladding material is then retained in the grooves defined between the flanges of the top-hat section and the structural elements, thereby forming the wall. However, this arrangement leaves the fasteners exposed to external conditions as the cladding material does not extend over the channel in the top-hat section. This may result in relatively early failure of the wall in fire conditions.

It has been proposed to protect the upper edges of some wall cladding material from water penetration by the use of generally Z-shaped and h-shaped channel sections of PVC plastics. These channel sections define a downwardly-facing groove to receive the upper edge of a lower sheet of cladding material. They are secured to upright structural elements of the wall and to noggings extending between the structural elements by fasteners through an upper flange of the channel sections. An upper sheet of the cladding material sits on a web between the upper flange and the groove and is secured to the structural elements by fasteners therethrough.

Other PVC joiners have been used between sheets of cladding material, including H- shaped, but there are to hide the vertical join lines and do not provide any support to the sheets of cladding material.

The present invention aims to provide an improved arrangement for retaining sheets of cladding material in a wall system, that advantageously avoids points of weakness, that may provide improved fire-resistance and that may also provide for improved acoustic properties.

SUMMARY OF THE INVENTION

According to the present invention there is therefore provided a wall system comprising: at least two upright structural elements; an elongate mounting member extending from one to a second of the structural elements and comprising: i) an elongate mounting flange that is secured to the structural elements by fasteners; and ii) an elongate T-section retaining portion including a web extending from the mounting flange and a head portion, said head portion defining with the web and with the elongate mounting flange on at least one side of the web, and optionally with the structural elements on the other side of the web, upper and lower grooves on opposite sides of the web; and a layer of cladding material comprising at least two sheets of cladding material, an upper one of the two sheets having an edge portion thereof retained in the upper groove and being supported by the upper groove and a lower one of the two sheets having an edge portion thereof retained in the lower groove. As will be appreciated from the preamble above, the upright structural elements to which the elongate mounting member is secured are preferably studs. For example, the structural elements may be steel C-section or top-hat section studs or timber studs. However, where appropriate the wall system of the invention may include alternative upright structural elements as will be appreciated by those of skill in the art.

It will also be appreciated that the wall system as defined above is illustrative of a section of a wall, or is a very small wall. Depending on the size of the wall to be erected, the wall system may include a plurality of vertically spaced elongate mounting members, preferably horizontal, extending between and secured to the structural elements, wherein each of the elongate mounting members retains a respective pair or pairs of sheets of cladding material in the upper and lower grooves thereof. This arrangement allows the wall system to reach any desired height. Likewise, it will be appreciated that the addition of further spaced structural elements, and corresponding mounting members, will allow the wall system to reach any desired length. Any one elongate mounting member may open more than two structural elements. Furthermore, it will be appreciated by those of skill in the art that the elongate mounting members and cladding material may be applied to one side only of the structural elements, for example where the wall system is an exterior wall, or may be applied to opposing sides of the structural elements, for example where the wall system is an internal wall.

A substantial advantage of the wall system of the invention is that the at least two sheets of the layer of cladding material may be secured to the structural elements, at least during the initial construction phase, without any fasteners passing through them. This can substantially accelerate the speed of construction of the wall and arises because the upper and lower edges of each sheet are securely retained in the lower and upper grooves of respective elongate mounting members. Shrinkage of the sheets of cladding material in fire situations is accommodated by the grooves of the elongate mounting member(s) so that the layer of cladding material remains secured to the structural elements while the elongate mounting member(s) remains secured. Thus, advantageously, in the wall system of the invention, at least some, and most preferably all, of said fasteners securing said elongate mounting member to the -structural elements underlie the layer of cladding material. This may also have substantial advantage in fire situations, in that at least some, and most preferably all, of the fasteners securing the elongate mounting member to the structural elements are protected by the layer of cladding material and can therefore remain structurally integral for a longer period of time.

In some circumstances, particularly if the elongated mounting member is of metal, the elongated structural member may replace a separate noggin in the wall system, and this can also accelerate the speed of construction.

It may under some circumstances be preferred to secure the upright or vertical edges of the at least two sheets of cladding material to the structural elements, but as the upper and lower edges are held securely by respective elongate mounting members this is advantageously not necessary. Upright or vertical edges of adjacent sheets not aligned with a structural element may be joined by a backing sheet behind the edge portions bonded or secured by fasteners to the edge portions.

In order to provide an even more secure wall system that facilitates better insulation from fire and noise, the wall system of the invention may include at least one further layer of cladding material. In this embodiment of the invention, the further layer of cladding material comprising at least two sheets of cladding material overlies said first mentioned layer of cladding material, a further elongate mounting member being mounted on said first-mentioned layer of cladding material and comprising: i) an elongate mounting flange that is secured to said first-mentioned layer of cladding material by fasteners; and ii) an elongate T-section retaining portion including a web extending from the mounting flange and a head portion, said head portion defining with the web and with the elongate mounting flange on at least one side of the web, and optionally with said first- mentioned layer of cladding material on the other side of the web, upper and lower grooves on opposite sides of the web; an upper one of the two sheets of said further layer of cladding material having an edge portion thereof retained in the upper groove of the further elongate mounting member and being supported by said upper groove and a lower one of the two sheets of said further layer of cladding material having an edge portion thereof retained in the lower groove of the further elongate mounting member.

Generally, as will again be appreciated by those of skill in the art, in this embodiment the number of vertically-spaced further elongate mounting members mounted on the first- mentioned layer of cladding material will be dependant on the height of the wall system. Preferably, the further elongate mounting member(s) retaining the further layer of cladding material are offset upwardly or downwardly relative to the first-mentioned elongate mounting member(s). This arrangement provides added protection to the first layer of cladding material by ensuring that the horizontal joins in the further layer of cladding material are not aligned with the horizontal joins in the first-mentioned layer of cladding material.

To provide even further strength and resilience to this embodiment of the wall system, preferably at least some, and most preferably all, of the fasteners securing said further elongate mounting member to said first-mentioned layer of cladding material pass through the first-mentioned layer of cladding material and engage the structural elements. This provides for securing the sheets of the first-mentioned layer of cladding material directly to the structural elements.

Furthermore in this embodiment, as with the fasteners associated with the elongate mounting member of the first-mentioned layer of cladding material, advantageously at least some, and most preferably all, of the fasteners securing said further elongate mounting member to said first-mentioned layer of cladding material underlie said further layer of cladding material.

The sheets of cladding material in the first-mentioned and/or further layers may be plasterboard, preferably first-resistant plasterboard, or any other suitable cladding material. In most instances, it will be preferred to provide some aesthetic appeal to the wall system given that the wall will generally be open to public view and the head of the T-section retaining portion of the elongate structural member(s) may otherwise be exposed. Accordingly, in a preferred embodiment an aesthetic layer of sheet material overlies and is secured to an outermost layer of cladding material, for example the first-mentioned or a second layer of cladding material. The type of material used for the aesthetic layer is not particularly limited and will be readily appreciated by those of skill in the art. In one embodiment, the aesthetic layer is of standard core plasterboard.

The aesthetic layer may be secured to the outermost layer of cladding material by, for example, a bonding agent. However, preferably, the aesthetic layer is secured by fasteners.

In order to render this embodiment of the wall system even more secure and resilient, the aesthetic layer is preferably secured by fasteners, preferably screw-threaded fasteners, at least some of which are secured through the head portion of the T-section retaining portion of the elongate mounting member(s) retaining the at least two sheets of the outermost layer of cladding material. Where the outermost layer of cladding material is the first-mentioned layer, most preferably all of said fasteners associated with the aesthetic layer are secured through the head portion of the T-section retaining portion of the elongate mounting member(s) retaining the at least two sheets of the first-mentioned layer of cladding material.

In the case where the outermost layer of cladding material is a further layer of cladding material as described above, the aesthetic layer may also be secured with at least some fasteners that extend through the aesthetic layer and the further layer of cladding material and further through the head portion of the T-section retaining portion of the elongate mounting member(s) associated with the next adjacent layer of cladding material. Where there are two layers of cladding material, the outermost layer would be the second layer and the next adjacent layer would be the first-mentioned layer. In this arrangement, particularly in combination with the above described securing arrangement for the further layer of cladding material to the first-mentioned layer of cladding material, a very secure and resilient structure may be obtained that provides layers of protection to the internal structural elements from any external conditions.

Turning to the actual form of the elongate mounting member, preferably the mounting flange of the or each elongate mounting member projects beyond the head portion of said elongate mounting member and the fasteners securing that elongate mounting member pass through said projecting portion of the mounting flange. This facilitates securing the elongate mounting member to the existing structure of the wall system by providing ready access for and to the fasteners. Most advantageously the projecting portion of the mounting flange projects beyond the part of the head portion defining the upper groove of said elongate mounting member.

Securing each elongate mounting member through an upper flange portion, for example said projecting portion of the mounting flange on the upper side of the elongate mounting member, greatly facilitates the construction of a wall in accordance with the invention. In one embodiment, for convenience, referring to only two adjacent upright structural elements and to only one layer of cladding material with one sheet at each level, a bottommost sheet of cladding material has a lower edge portion supported in an upwardly open channel section secured to the structural elements and/or the floor. The channel section corresponds to the upper groove of the elongate, mounting members. The upper edge portion of the bottommost sheet is received in the lower groove of a first elongate mounting member, the web of which is seated on the upper edge of the bottommost sheet. The first elongate mounting member is then secured to the upright structural elements using fasteners through the upper projecting flange portion. The next sheet of cladding material, at the next level, is then supported by the first elongate mounting member, with its lower edge portion retained in the upper groove and its lower edge seated on the web. The upper edge portion of that sheet is then received in the lower groove of a second elongate mounting member and the process is repeated for further levels of sheets of cladding material and further elongate mounting members. A very high wall can be built using this system of sheet-to-sheet support through the webs of the mounting members, and the elongate mounting members can replace normal noggins between the structural elements. The upper edge portion of the uppermost sheet of cladding material may be received in an inverted channel section (downwardly open) secured to the structural elements or to a roof or ceiling structure. '

The mounting flange of the or each elongate mounting member may extend to both sides of the web of the T-section retaining portion of that member. However, this is not necessary when the flange is only secured to the structural elements by fasteners to one side of the web. Preferably, therefore the mounting flange does not project downwardly below the web and therefore does not define the lower groove of that elongate mounting member. When the mounting flange does not define the lower groove of the elongate mounting member, one wall of the groove may be discontinuous in that it may be defined by the upright structural elements that are spanned by the elongate mounting member. The term "groove" shall be construed to encompass an elongate open-ended recess or channel one or both walls of which may be discontinuous but which are such as to restrain lateral movement of the edge portion of the sheet(s) of cladding material retained therein. Preferably, the wall defined by the respective part of the head portion is continuous to give added bending strength to the elongate mounting member.

In a preferred embodiment, the parts of the head portion of the or each elongate mounting member that respectively partly define the upper and lower grooves of said elongate mounting member have an equal and opposite extent from the web. However, this is not essential and a number of variations are possible. For example, said parts of the head portion may have different extents from the web; said parts may flare outwardly from the web by up to about 5° to facilitate insertion of the respective sheet edge portion; and/or said parts may have different thicknesses, for example as a result of different folds of sheet material.

Preferably, the outer face of the head portion of each elongate mounting member is substantially planar, that is entirely flat or, for example, slightly corrugated or slightly convex. The elongate mounting member(s) may be formed of any suitable material, including metallic such as coated steel or plastics. Where the wall system is being used for fire prevention purposes, however, it is preferred that the elongate mounting member(s) is metallic, especially if the member is to replace a standard noggin. The elongate mounting member may be extruded or be formed by any suitable means, but a metallic member is preferably rolled or pressed from sheet material.

The fasteners described herein may be screws or fasteners or a selection of both depending upon the particular use.

Preferred embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:

Fig. IA illustrates one embodiment of elongate mounting member used in the invention mounted on a C-section steel stud;

Fig. IB illustrates the elongate mounting member of Figure 1 mounted on a timber stud;

Fig. 2 is a cross-sectional view of a wall system in accordance with the invention using the elongate mounting member of Figure 1, including an enlarged circled portion; Fig. 3 A is a sectional view from above of the wall system of Figure 2;

Fig. 3B is a cut away elevational view of the wall system of Figures 2 and 3A, excluding cladding materials;

Fig. 4A is an end view of another embodiment of elongate mounting member for use in the invention; Fig. 4B is a perspective view of the elongate mounting member of Fig. 4A;

Fig. 5 A is an end view of the elongate mounting member of Figures 1 and 2; Fig. 5B is a perspective view of the elongate mounting member of Fig. 5 A; Fig. 6A is an end view of another embodiment of elongate mounting member for use in the invention; and Fig. 6B is a perspective view of the elongate mounting member of Fig. 6 A. Referring to Figures IA and IB, an initial step in preparing a wall system in accordance with an embodiment of the invention is illustrated. This involves securing an elongate mounting member 11 between at least two studs 12 (one only shown) of a wall system.

The studs 12 may be C-section steel studs 12a, or may be timber studs 12b. The mounting member 11 is secured to the studs 12 by respective fasteners such as the screw 13 illustrated schematically. The screw 13 extends through a mounting flange portion 14 of the elongate mounting member 11. The mounting flange portion 14 extends from a web

15 of a T-section retaining portion 16 that includes the web 15 and a head portion 17 and projects upwardly beyond the head portion 17.

The T-section retaining portion 16 and the mounting flange portion 14 define with the web 15 an upper groove or recess 18, while the T-section retaining portion 16 and the studs 12 define with the 15 a lower groove or recess 19. These recesses 18, 19 receive cladding material (as illustrated in Figure 2).

Referring to the enlarged circled portion of Figure 2, a wall system 20 is illustrated including a C-section stud 21 to which cladding material 22 is secured. The cladding material 22 may be selected depending on the desired characteristics for the wall system 20, such as fire resistance or acoustic insulation, but will generally be in the form of sheets of plasterboard and is mounted on the stud 21 by means of the horizontal mounting members 11 of Figure IA. This cladding material is in the form of a first layer of cladding material 22a and second layer of cladding material 22b. The mounting member 11a that retains the sheets of cladding material 22a of the first layer of cladding material is secured directly to the stud 21 through the projecting part of its mounting portion 14. Therefore, the screw fastener 13 is accessible from above the head portion 15 and extends well into the stud 21. The edge portions of the sheets of cladding material 22a are closely received in recesses 18, 19. In practice, the lower sheet of the cladding material 22a would be put in position against the stud 21 and the elongate mounting member 11 seated on it before the member 11 is secured to the stud 21 as described with reference to studs 12a and 12b of Figures 1 and 2. The upper sheet of the cladding material 22a would then be supported in the recess 18, seated on the web 15, and the upper edge portion (not shown) of that sheet would then be secured by another elongate member 11 in the same manner.

Similarly, the sheets of cladding material 22b of the second layer of cladding material are retained by recesses 18 and 19 defined by the T-section retaining portion 16 and the mounting portion 14 of the mounting member l ib. . However, for this layer the screw fastener 13b extends through the cladding material 22a of the first layer of cladding material and into the stud 21. As shown in the non-enlarged portion of Figure 2, the mounting member l ib is offset relative to the mounting member 11a upwardly by about one half the height of the upper sheet of the cladding material 22a. As also shown in the non-enlarged portion of Figure 2, this structure is duplicated on the opposed side of the wall system 20, so that the wall is an internal wall.

An aesthetic layer of material 23 is applied to the second layer(s) of cladding material 22b and secured by screws 24 to hide the head portion of the mounting members l ib of the second layer 22b. These screws 24 are positioned such that some of the screws 24a pass through the aesthetic layer material 23 and the second layer of cladding material 22b and are secured in the head portion of the mounting member 11a of the first layer of cladding material, while other screws 24b pass through the aesthetic layer material 23 and are secured in the head portion 17 of the mounting member l ib of the second layer of cladding material 22b.

It will be appreciated that this structure provides substantial protection at points of weakness, in particular where the first layer of cladding material 22a is secured to the studs 21, by protecting the screws 13a, but also at the seams of the cladding material 22a of the first layer of cladding material, defined at the web 15 of the mounting member 11a. This is due to cladding material 22a of the first layer and cladding material 22b of the second layer overlying these points of weakness respectively. The structure also permits fast construction since the layers of cladding material need not be secured o the studs 21 by fasteners, except as described, and the mounting members 11a may act as noggins. Additionally, the recesses 18 and 19 permit shrinkage of the sheets of cladding material in fire circumstances while still retaining the sheets. Turning to Figures 3A and 3B, a wall system 30 is illustrated in cut away plan view, and also as an elevational view with cladding material 22 and aesthetic layer of material 23 removed. In this instance, the wall system 30 includes C-section studs 12a between which mounting members 11 and 11' extend as noggins, cladding material 22 being applied to both sides of the C-section studs 12a, as would be the case in an internal wall. The cladding material 22 therefore defines a wall cavity 31. Cladding material 22a is retained by the mounting members 11, 11' in the manner illustrated in Figure 2. Thus, cladding material extends between mounting members 11 and 11'. Cladding material is also retained by a channel section 32 secured to the studs 12a at floor level and by the mounting member 11, and further cladding material is retained by mounting member 11' and by a channel section 33 secured to the studs 12a at ceiling level. Once the cladding material 22a of the first layer of cladding material is applied to the wall system 30, a second mounting member(s) (best illustrated in Figure 2 as member 1 Ib) is secured at a mid point X of the upper sheet of cladding material 22a of the first layer of cladding material. The cladding material 22b of the second layer of cladding material may then be applied.

It will be appreciated from the description above that Figures IA, 2, 3A and 3B all illustrate the same, or part of the same, wall system.

A number of forms for the mounting member 11 are illustrated in Figures 4-6. These are, in each case, formed from a sheet of metallic material such as galvanised or otherwise coated steel, by rolling and/or pressing. In the first two embodiments, represented in Figures 4 and 5, the mounting member 11 includes a mounting flange portion 14 that extends well beyond an upper distal edge 41 of the head portion 17 of the T-section retaining portion- 16. As previously noted, this facilitates easy mounting of the mounting portion 14 by means of a fastener to a stud of a wall system. The lower part of the head portion 17 is formed by overlapping folded portions of the sheet of material, while the web 15 extends perpendicularly from approximately the mid-line between the distal edge 41 and the fold of the lower part of the head portion. The mounting flange portion 14 extends perpendicularly upwardly from the opposite edge of the web 15. The mounting member 11 includes upper fold 42 and channel 43 to provide strength and/or resilience to the mounting member 11 , but if desired these may be omitted to provide the mounting member 11 of Figures 5A and 5B, which is identical to the mounting members 11 illustrated in Figures IA, IB, 2, 3A and 3B. The overlapping folded portions of the lower part of head portion 17 are slightly spaced in Figures 4A and 4B but abutting in Figures 5 A and 5B.

With reference to Figures 6 A and 6B, the mounting member 61 has a substantially H- section. The mounting member 61 includes a T-section retaining portion 66 that is the same as that illustrated for the mounting member 11 in Figures 4A and 4B except that the head portion 67 is inverted, with the fold 42 in the lower part of the head portion. The mounting flange portion 64 of the mounting member 61 differs from the mounting flange portion 14 in that it includes a lower flange 70 that extends downwardly from the web 71 of the T-section retaining portion 66 and then doubles back on itself to form the upper part of the mounting portion 64. The upper part of the mounting portion 64 is inclined inwardly at a slight angle relative to the flange 70, from the level of the web 71. This makes it possible to include a folded Hp 72 on the distal edge of the upper part of the mounting portion 64 to provide added resilience to the mounting member 61, while still facilitating a flush positioning of the mounting member 61 on the studs of the wall system. The upper part of the mounting member 64 and the upper part of the head portion 67 of the T-section retaining portion 66 define with the web 71 a recess 68 in which the edge portion of an upper sheet of cladding material may be supported and retained. Similarly, the flange 70 and the lower part of the head portion 67 define with the web 71 a recess 69 in which the edge portion of a lower sheet of cladding material may be retained. Any of the features of the mounting flange portion 64 may be applied to the mounting flange portion 14 of Figures 4 A and B and 5 A and B.

The invention has been described by way of non-limiting example only and many modifications and variations may be made thereto without departing from the spirit and scope of the invention described. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims

CLAIMS:

1. A wall system comprising: at least two upright structural elements; an elongate mounting member extending from one to a second of the structural elements and comprising: i) an elongate mounting flange that is secured to the structural elements by fasteners; and ii) an elongate T-section retaining portion including a web extending from the mounting flange, and a head portion, said head portion defining with the web and with the elongate mounting flange on at least one side of the web, and optionally with the structural elements on the other side of the web, upper and lower grooves „ on opposite sides of the web; and a layer of cladding material comprising at least two sheets of cladding material, an upper one of the two sheets having an edge portion thereof retained in the upper groove and being supported by the upper groove and a lower one of the two sheets having an edge portion thereof retained in the lower groove.

2. A wall system according to claim .1, wherein at least some of said fasteners securing said elongate mounting member to the structural elements underlie said layer of cladding material.

3. A wall system according to claim 2, wherein all of said fasteners securing said elongate mounting member to the structural elements underlie said layer of cladding material.

4: A wall system according to any one of claims 1 to 3, wherein an aesthetic layer of sheet material overlies and is secured to said layer of cladding material.

5. A wall system according to claim 4, wherein the aesthetic layer of sheet material is secured to said layer of cladding material by fasteners and at least some of the fasteners associated with the aesthetic layer are secured through the head portion of the elongate mounting member.

6. A wall system according to any one of claim 1 to 3, wherein a further layer of cladding material comprising at least two sheets of cladding material overlies said first mentioned layer of cladding material, a further elongate mounting member being mounted on said first-mentioned layer of cladding material and comprising: i) an elongate mounting flange that is secured to said first-mentioned layer of cladding material by fasteners; and ii) an elongate T-section retaining portion including a web extending from the mounting flange and a head portion, said head portion defining with the web and with the elongate mounting flange on at least one side of the web, and optionally with said first-mentioned layer of cladding material on the other side of the web, upper and lower grooves on opposite sides of the web; an upper one of the two sheets of said further layer of cladding material having an edge portion thereof retained in the upper groove of the further elongate mounting member and being supported by said upper groove and a lower one of the two sheets of said further layer of cladding material having an edge portion thereof retained in the lower groove of the further elongate mounting member.

7. A wall system according to claim 6, wherein at least some of the fasteners securing said further elongate mounting member to said first-mentioned layer of cladding material pass through the first-mentioned layer of cladding material and engage the structural elements.

8. A wall system according to claim 6 or 7, wherein at least some of the fasteners securing said further elongate mounting member to said first-mentioned layer of cladding material underlie said further layer of cladding material.

9. A wall system according to any one of claims 6 to 8, wherein said further elongate mounting member is offset upwardly or downwardly relative to said first-mentioned elongate mounting member.

10. A wall system according to any one of claims 6 to 9, wherein an aesthetic layer of sheet material overlies said further layer of cladding material.

11. A wall system according to claim 10, wherein the aesthetic layer is secured to said further layer of cladding material by fasteners, and at least some of the fasteners associated with the aesthetic layer are secured through the head portion of the further elongate mounting member.

12. A wall system according to claim 10 or 11, wherein at least some of the fasteners associated with the aesthetic layer are secured through the head portion of the first- mentioned elongate mounting member.

13. A wall system according to any one of the preceding claims, wherein the mounting flange of the or each elongate mounting member projects beyond the head portion of said elongate mounting member and the fasteners securing that elongate mounting member pass through said projecting portion of the mounting flange.

14. A wall system according to claim 13, wherein said projecting portion of the mounting flange projects beyond the part of the head portion defining the upper groove of said elongate mounting member.

15. A wall system according to any one of the preceding claims, wherein the mounting flange of the or each elongate mounting member does not define the lower groove of said elongate mounting member.

16. A wall system according to any one of the preceding claims, wherein the parts of the head portion of the or each elongate mounting member that respectively partly define the upper and lower grooves of said elongate mounting member have an equal and opposite extent from the web.

17. A wall system according to any one of the preceding claims, wherein the outer face of the head portion of the or each elongate mounting member is substantially planar.

18. A wall system according to any one of the preceding claims, wherein the or each elongate mounting member is metallic.

19. A wall system according to claim 18, wherein the or each elongate mounting member is folded from sheet metal.

20. A wall, system substantially as herein described with reference to the accompanying drawings.