METHOD FOR MOUNTING WALL PANELS & WALL PANEL SYSTEM

Abstract

A method for mounting wall panels (1a,1b) to a wall (27). The method including providing first and having a thermoplastics substrate (3) and a protective film (7) applied over a major surface (11) of the substrate, said protective film (7) having a thickness of at least 140 m and including a textured surface (17) having a multiplicity of micro-peaks and/or micro-troughs randomly arranged, thereby providing a light diffusing and/or light scattering effect; mounting the first and second laminated wall panels (1a,1b) onto the wall (27); and inserting a gap filling sealant (21) into a gap between adjacent peripheral portions (29a,29b) of the first and second wall panels (1a,1b). A wall panel system is also disclosed.

Claims

1. A method for mounting wall panels to a wall, said method including, providing: first and second laminated wall panels, each having a thermoplastics substrate and a protective film applied over a major surface of the substrate, said protective film having a thickness of at least 140 m, and said protective film having a textured surface including a multiplicity of micro-peaks and/or micro-troughs randomly arranged, thereby providing a light diffusing and/or light scattering effect; mounting the first and second laminated wall panels onto the wall; and inserting a gap filling sealant into a gap between adjacent peripheral portions of the first and second wall panels.

2. A method according to claim 1, wherein the textured surface is an embossed textured surface.

3. A method according to claim 1, wherein the textured surface is an outer surface of the wall panel.

4. A method according to claim 1, wherein the visual appearance of the gap filling sealant substantially matches the visual appearance of the textured surface of the protective film.

5. A method according to claim 1, wherein the gap filing sealant is a settable sealant.

6. A method according to claim 1, wherein the gap filing sealant is a clear sealant.

7. A method according to claim 1, wherein the gap filing sealant has a cloudy appearance.

8. A method according to claim 1, including attaching at least one of the first and second wall panels to the wall by double-sided adhesive tape or film.

9. A method according to claim 8, including applying double-sided adhesive tape or film to the wall; and wherein mounting the first and second wall panels to the wall includes mounting a peripheral portion of the first wall panel onto the double-sided adhesive tape or film; mounting a peripheral portion of the second wall panel onto the double-sided adhesive tape of film, such that the peripheral portions are located adjacent to one another.

10. A method according to claim 1, including bonding a backing member to the wall, wherein the boding member is arranged to support at least one of the first and second wall panels on the wall.

11. A method according to claim 10, including applying double-sided adhesive tape or film to at least one of the backing member and the wall panel.

12. A method according to claim 11, wherein mounting the first and second wall panels to the wall includes mounting a peripheral portion of the first wall panel onto the double-sided adhesive tape or film; mounting a peripheral portion of the second wall panel onto the double-sided adhesive tape of film, such that the peripheral portions are located adjacent to one another.

13. A method according to claim 1, wherein at least one of the wall panels is transported to an installation site in a rolled up configuration, and including unrolling the wall panel prior to mounting on the wall.

14. A method according to claim 1, wherein the thickness of the substrate for at least one of the first and second wall panels is greater than or equal to 1 mm; and/or the thickness of the substrate for at least one of the first and second wall panels is less than or equal to 2 mm.

15. A method according to claim 1, wherein the film includes a plasticizer content which is greater than or equal to 15%; and/or the film includes a plasticizer content which is less than or equal to 25%.

16. A method according to claim 1, wherein the film has a density in the range 1.25 g/cm.sup.3 to 1.35 g/cm.sup.3.

17. A method according to claim 1, wherein the film is attached to the wall panel by means of: a pressure sensitive adhesive, such as a solvent acrylic adhesive; or heat during extrusion of the substrate.

18. A method according to claim 1, wherein the film has a pre-textured thickness which is greater than or equal to 120 m; and/or the film has pre-textured thickness which is less than or equal to 200 m.

19. A method according to claim 1, wherein the height of the texture is greater or equal to 15 m; and/or less than or equal to 80 m.

20. A method according to claim 1, wherein the average surface roughness of the textured surface is greater than or equal to 2 m; and/or is less than or equal to 12 m.

21. A method according to claim 1, wherein the surface gloss measurement of the textured surface is greater than or equal to 1GU and/or is less than or equal to 20GU.

22. A method according to claim 1, wherein the film includes a thermoplastic such as at least one of PVC, PMMA and PVDF.

23. A method according to claim 1, wherein the film comprises a PVC film, and preferably a monomeric calendared PVC film.

24. A method according to claim 1, wherein at least one of the wall panels includes a printed image.

25. A method according to claim 24, wherein at least one image is printed on to at least one of: the film; the substrate; and an intermediate layer such as an adhesive layer.

26. A method according to claim 1, wherein the substrate for at least one of the first and second wall panels includes a thermoplastic, such as at least one of PVC and ABS.

27. A wall panel system including: at least first and second laminated wall panels, each having a thermoplastics substrate and a transparent protective film applied over a major surface of the substrate, said protective film including a textured surface; and a gap filling sealant for filling a gap between adjacent peripheral portions of the first and second wall panels; wherein the textured surface of the protective film includes a multiplicity of micro-peaks and/or micro-troughs randomly arranged, thereby providing a light diffusing and/or light scattering effect.

28. A system according to according to claim 27, wherein each wall panel is arranged according to the wall panels used in the method of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which:

[0071] FIG. 1 is a cross-sectional view of a wall panel used in a method and system in accordance with the invention;

[0072] FIG. 2 is an enlarged isometric view of the wall panel of FIG. 1, showing part of a textured outer surface of the wall panel, partly peeled back for illustrative purposes;

[0073] FIG. 3 is a diagrammatic cross-sectional view of part of a film which forms the textured outer surface of the wall panel, together with a layer of adhesive, the section line being shown in FIG. 2;

[0074] FIG. 4 shows images of a prior art wall panel surface profile, for comparison with FIGS. 5 and 6;

[0075] FIGS. 5 and 6 are surface profiles of wall panels in accordance with the invention, in particular surface profiles of a textured outer surface of the wall panels;

[0076] FIG. 7 is a diagrammatic cross-sectional view of two wall panels similar to that shown in FIG. 1 mounted on an even surface;

[0077] FIG. 8 is a diagrammatic cross-sectional view of two wall panels similar to that shown in FIG. 1 mounted on an uneven surface; and

[0078] FIG. 9 is a diagrammatic cross-sectional view of two wall panels similar to that shown in FIG. 1 mounted on a surface, and using a backing strip seated behind adjoining edges of the wall panels.

DETAILED DESCRIPTION OF THE INVENTION

[0079] FIG. 1 shows a diagrammatic cross-sectional view of a wall panel 1 used in a wall panel system and method according to the invention.

[0080] The wall panel 1 has a laminated structure. The wall panel 1 includes a base (substrate) layer 3, optionally a printed layer 5, and a protective film 7.

[0081] The base layer 3 comprises a sheet of thermoplastics material, such as a sheet of PVC (Polyvinyl chloride). The base layer 3 has a thickness T, which is typically in the range 1 mm to 2 mm. The base layer 3 has a length L, which is typically in the range 1.5 m to 3 m. The base layer 3 has a width W, which is typically in the range 0.5 m to 1.5 m. The density of the base layer is typically around 1.4 g/cm.sup.3. Typically, the base layer 3 is opaque.

[0082] Optionally, at least one image 5 can be printed onto a major surface 11 of the base layer. For example, the image can cover a substantial portion of the major surface, or even the entire major surface 11. Alternatively at least one discrete images 11 can be printed on the major surface, for example in the form of a pattern. In some arrangements, the image 11 can be split across a plurality of wall panels 1, for example when depicting a panoramic or scenic view. Typically, the base layer 3 is coloured white when at least one image is printed there on.

[0083] The protective film 7 overlies the major surface 11 of the base layer, and any images 5 formed thereon. The film 7 is bonded to the major surface 11 of the base layer and/or the image(s) 5 by a pressure sensitive adhesive 13. The adhesive 13 bonds an inner surface 15 of the film to the major surface 11 of the base layer and/or the image(s) 5. The inventor has discovered that a pressure sensitive solvent acrylic adhesive is well suited to this function. This type of adhesive fixes the position of the film 7 relative to the base layer 3. In tests, the inventor found that when water based acrylic adhesives were used, there was a tendency for the film 7 to move somewhat relative to the base layer 3, in particular to shrink inwards from the edges of the base layer, which is highly undesirable. Furthermore the adhesive 13 is sufficiently strong to allow the wall panel to be cut using a fine tooth hand saw, a circular saw or jig saw, without lifting the film at its edge. The adhesion remains effective against hot water at normal shower temperature and heat from a towel rail set at not less than 30 mm from the wall surface.

[0084] The film 7 is made from PVC. Preferably the film 7 is a monomeric calendared PVC film. The film 7 includes a plasticizer content which is in the range 15% to 25%, and preferably in the range 18% to 21%. Plasticiser content is measured in parts per hundred of PVC resin. The plasticizer content is an important part of the invention since it has a significant impact on the hardness of the film, and hence the ability of the wall panel 1 to resist scuffing and scratching in use. The range has been specifically chosen to balance the ease of application of the film to the wall panel and the surface hardness of the finished product. The film 7 has a density in the range 1.25 g/cm.sup.3 to 1.35 g/cm.sup.3, and is preferably around 1.29 g/cm.sup.3. This also has an impact on scuff and scratch resistance.

[0085] The film 7 has a textured outer surface 17. The textured surface 17 is formed by an embossing process.

[0086] The film 7 preferably has a pre-textured thickness in the range 120 m to 200 m (excluding the thickness of the adhesive layer 13the adhesive layer 13 typically adds a few microns of thickness). A particularly preferred pre-textured thickness is around 150 m.

[0087] The embossing process includes heating the film 7 to soften it, and rolling at least one roller (not shown) over the film 7, or passing the film 7 through a pair of rollers (not shown). At least one of the rollers includes a textured outer surface for treating the outer surface 17 of the film. The outer surface of the roller includes a granular texture. The granular texture preferably has a fine texture similar to a fine, very fine or extra fine abrasive paper, such as a silicone carbide paper, for example according to ISO 6344/FEPA Grit designation. The granular texture typically has an average grit size in the range 100 m to 20 m, and preferably in the range 60 to 30 m. The textured surface 17 produced in the film is a fine stipple-like texture 17. The texture 17 extends across substantially the entire outer surface of the film, in a fairly even manner. That is, the density of the texture is relatively even across the film. The stippled texture 17 has no discernible pattern. It is essentially a random arrangement of micro-peaks and micro-troughs.

[0088] The height of the embossed texture 17, for example from its highest peak to its lowest trough, is typically in the range 15 km to 80 m, and is preferably around 25 m to 40 m. Thus the overall thickness of the textured film is typically in the range 135 m to 280 m. A particularly preferred example has a pre-textured thickness of around 150 m, and an embossed texture thickness of around 25 m, giving the textured film a thickness of around 175 m.

[0089] The film 7 is manufactured with the adhesive 13. The wall panel 1 is manufactured by applying the film 7 to the base layer 3 by means of a laminating machine. This machine applies the required heat and pressure to achieve a strong bond between the film 7 and base layer 3 and/or printed images 5. The adhesive 13 layer adds slightly to the combined thickness of the base 3 and film 7.

[0090] A significant advantage of the textured surface 17 is that is has good light diffusing and/or light scattering properties. Together with the transparency of the film this creates a satin rather than a gloss or matt surface. The effect of the texture 17 and thickness of the film 7 makes wall unevenness less visible, and helps to hide joins between panels when mounted in the manner described below. The texture 17 also helps to prevent scratching and scuffing occurring. When scratching and/or scuffing occurs, the texture 17 means that it is less visible to the casual observer.

[0091] A further advantage of the textured film 7 is its resistance to scuffing and scratching. This is demonstrated by the results of a rubbing test shown below, which compares a wall panel according to the invention with known wall panels.

[0092] Comparative Testing

[0093] Rub Test

[0094] A Satra STM 462 rub tester was used to compare the above described inventive material to others. The tests were conducted using a loading pressure of 5 psi and a pad pre-soaked in abrasive paste with a six micron particle size, to replicate cleaning materials. The materials tested were graded from 1 showing severe damage or colour transfer to 5 showing no damage or colour transfer. The results in Table 1 below are based on the average values determined from 3 replicate tests.

TABLE-US-00001 TABLE 1 Wall Panel Material 50 Rubs 100 Rubs 200 Rubs 500 Rubs Melamine Gloss (Prior Art) 4-5 4 3 2 Melamine Matt (Prior Art) 4-5 4-5 4 3 PVC Satin (Prior Art) 4 3 2 2 Acrylic Gloss (Prior Art) 3-4 3 2 1 Wall panel according to the 5 5 4-5 4-5 invention

[0095] The fine and even textured surface 17 has other advantages compared to a smooth surface. Firstly it conceals dust, light scratching and marks, which are clearly visible on a smooth and particularly a smooth gloss surface. Secondly it is fine enough to make surface contaminants and the cleaners used to remove them, easily removable by rinsing and wiping with water. Graffiti spray paint can be removed with white spirit or specialist cleaners. Fine scratches can be removed by use of multi surface polish.

[0096] The combination of surface hardness and the fine and even emboss makes the surface resistant to scuff and scratch. Scotch type abrasive pads and abrasive cleaners can therefore be used to clean the wall panel 1.

[0097] Optionally, UV protecting additives can be included in the film 7 to improve resistance of the base layer 3 and the printed image 5 to the effect of sunlight. This helps to prevent discolouration of the printed images 5 and/or the base layer 3.

[0098] Surface Roughness (Ra)

[0099] The surface roughness of two samples of the invention was determined and compared with a conventional satin PVC wall panel. The surface roughness of the textured surface was determined using a Proscan 2000A optical profilometer fitted with a confocal probe, having a Z-direction measuring range of 400 m and a resolution of 22 nm. The nominal characteristics of the system satisfy the requirements of BS EN ISO 25178-602: 2010. Two sample tiles (a) and (b) of each wall panel were used for the test.

[0100] The average roughness amplitude (Ra) was determined on the textured surface of the sample.

[0101] Five replicate determinations were made on individual samples in both directions over a prescribed length using the following test parameters:

[0102] Panel 1 (Prior Art Satin PVC Wall Panel):

[0103] Scan length=4 mm; Step interval=0.003 mm; Surface filter=99; Roughness filter=0.8 mm.

[0104] Panels 2 and 3 (Samples of Wall Panels in Accordance with the Invention):

[0105] Scan length=12.5 mm; Step interval=0.008 mm; Surface filter=99; Roughness filter=2.5 mm.

[0106] The results are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Average Roughness, Ra (m) Panel 1 Panel 2 Panel 3 (prior art) (invention) (invention) Replicate X Y X Y X Y 1 0.30 0.22 7.14 9.24 3.56 3.72 2 0.24 0.20 6.78 6.68 4.56 3.96 3 0.27 0.21 5.93 8.39 3.40 4.17 4 0.40 0.26 8.13 8.09 5.75 5.40 5 0.30 0.23 7.35 7.92 5.14 4.10 6 0.24 0.21 8.15 8.33 4.33 4.33 Mean 0.29 0.22 7.23 8.11 4.46 4.28 Std. dev. 0.06 0.02 0.82 0.83 0.90 0.59

[0107] The X measurements were taken parallel with the short edge of the individual replicate tiles and Y measurements parallel with the long edge. The replicate measurements 1-3 were taken from the first tile (a) and measurements 4 to 6 from the other tile (b).

[0108] It can be seen from the results above that the panels according to the invention have a surface texture having an average surface roughness that is 15 to 36 times greater than the average surface roughness of a conventional non-textured wall panel.

[0109] 3D Surface Profile

[0110] In addition to the above, a 3D profile of the surface was acquired using the same profilometer used for the roughness measurements over a 5 mm5 mm area of the tile at a 0.01 mm step interval. The profile is shown with no applied filter.

[0111] The results of the 3D profiles can be seen in FIGS. 4 to 6. FIG. 4 shows the 3D profile of a prior art non-textured satin PVC wall panel. FIGS. 5 and 6 show 3D profiles of two samples of the invention. It is clear from FIGS. 5 and 6 that the textured surface comprises a random arrangement of micro-peaks and micro-troughs. The random micro-peaks and micro-troughs are distributed across the textured film 7, in a dense arrangement, which contrasts with conventional non-textured panel. The texture profile, which is a measure of the height of each trough and the depth of each peak, is shown by way of a scale in the 3D images.

[0112] The X and Y cross-sectional profiles of the texture (bottom left images in FIGS. 4 to 6) represent the micro-peaks and micro-troughs along the cross-sections in the X and Y axes respectively at the X and Y values indicated. The vertical bars at the left and right side of the graphs represent the vertical scales shown in the 3D images. The X and Y values mentioned above the X and Y direction profiles respectively indicate the X and Y values at which each profile is taken. The Z values mentioned above the X and Y direction profiles indicate the vertical height at which the profile meets the vertical bar at the left or right side of the graph. Thus the X and Y direction profiles are representative micro-peak and micro-trough profiles from the corresponding 3D image. The texture height TH, is shown in FIG. 5 in relation to the X and Y direction profiles across the 5 mm by 5 mm samples, as a measure of the maximum peak to the lowest trough along the profile for the sample.

[0113] The images in the top left hand corners of FIGS. 4 to 6 are plan views of the respective 3D images.

[0114] In FIG. 4, the vertical Z scale extends from 0 m to +70 m. However it can be seen from the X and Y profiles, and the 3D image, that the surface of the prior art wall panel is not random, but rather has a sinusoidal pattern in the Y direction, and no discernible pattern at all in the X direction. The pattern (texture) height is approximately 7 m.

[0115] In FIG. 5, the vertical Z scale extends from 0 m to +70 m. It can be seen from the X and Y cross-sectional profiles, and the 3D image, that the textured surface of the wall panel according to the invention comprises a dense arrangement of micro-peaks and micro-troughs, randomly arranged across the surface. The texture height is approximately 47 m in one direction and 43 m in the other direction.

[0116] In FIG. 6, the vertical Z scale extends from +60 m to +130 m. It can be seen from the X and Y cross-sectional profiles, and the 3D image, that the textured surface of the wall panel according to the invention comprises a dense arrangement of micro-peaks and micro-troughs, randomly arranged across the surface. The texture height is approximately 27 m, in one direction and 20 m in the other direction.

[0117] With regard to the density of texture, there are typically between 10 and 25 distinct peaks identified by the profilometer along each axial cross-sectional profile over a 5 mm by 5 mm sample tile. This gives a peak density of around 100 to 625 identifiable peaks in a 5 mm by 5 mm area. Of course, this is not a strict limit to the invention, but provides an approximate indication of the level of peak density, together with texture height, that a wall panel according to the invention has.

[0118] Surface Gloss

[0119] The surface gloss/reflectance of wall panel 1 (prior art) and panels 2 and 3 (invention) were measured at an angle of 85 using a Sheen tri-microgloss instrument. Two samples, Tile A & Tile B, of each wall panel were tested. Ten replicate areas were measured on each individual tile sample within the flat panel surface (excluding any join areas). The results are shown in Table 3 below.

[0120] Measurements using an angle of 85 are recommended for surfaces with a gloss measurement of <30 units when measured at 60. However all surfaces were measured at the same angle to enable direct comparison. The results are shown in Table 3 below.

TABLE-US-00003 TABLE 3 Surface Gloss Measurements 85 Panel 1 Panel 2 Panel 3 (prior art) (invention) (invention) Replicate Tile A Tile B Tile A Tile B Tile A Tile B 1 93.90 97.60 5.70 4.20 19.90 13.90 2 97.00 90.50 4.90 4.70 20.90 10.70 3 97.40 94.70 4.80 5.60 16.00 11.50 4 95.50 97.50 5.60 4.70 16.40 13.30 5 96.30 96.60 4.90 4.90 17.80 11.50 6 95.70 97.00 4.50 5.30 14.60 11.0 7 97.40 96.70 3.40 6.10 15.40 8.50 8 98.80 97.90 4.90 4.70 14.40 13.60 9 98.60 98.60 4.00 5.20 15.40 10.50 10 95.90 96.30 3.00 6.20 15.20 9.40 Mean 96.65 96.30 4.50 5.20 16.60 11.40 Std. dev. 1.50 2.31 0.87 0.65 2.23 1.78

[0121] It can be seen from the table that the prior art satin wall panel has a significantly higher gloss value than panels according to the invention. This shows that the random micro-peaks and micro-troughs tend to scatter and/or diffuse light falling up on them. Typically wall panels according to the invention have gloss values in the range 1.0GU to 20GU, and preferably in the range 2.0GU to 17GU.

Example

[0122] A preferred form of the wall panel 1 is arranged as follows: a PVC base layer 3 having a thickness of around 1000 m, optional printed layer 5, and protective textured film 7 having a thickness of around 175 m. Thus the total thickness of the wall panel is approximately 1.2 mm.

[0123] It has been found that this has arrangement has further advantages compared with prior art wall panels comprising solid sheet materials having thicknesses of around 2.0 mm to 2.5 mm. For example: [0124] 1) Non-level walls and joins between panels are not noticeable on casual examination when the wall panels 1 are mounted in accordance with the method described below. [0125] 2) The wall panel 1 weight is approximately half the weight of the prior art panels, which makes: [0126] A) It much easier to position the wall panel 1 accurately when fitting, the task can be achieved by one person rather than requiring two people, and the adhesive has less weight to support. [0127] B) The wall panel 1 is much more flexible and enables it to be rolled into a tube for packing and transportation. This is not practical with 2 mm thick material because of the extra rigidity. 2 mm sheet materials typically weigh 9 kg in the normal sheet size of 12202440 mm. They can only be packed flat. Because of the weight and large size, which makes it difficult to handle, the sheet has to be protected with expensive protective packaging. This in turn adds up to a further kg. The length and width of the pack means it is difficult to handle and is easily dropped. It cannot be collected by the customer from store and has to be delivered direct to the point of installation. This adds further cost. [0128] The 1.2 mm wall panel 1 according to the invention can be rolled for transportation, preferably with the film and print facing inwards. The wall panel 1 can be secured at a diameter, which is not so tight as to impart a permanent memory to the wall panel 1. It has been found that a diameter of approximately 30 mm for a 2440 mm long wall panel 1 does not impart permanent memory. No expensive packaging or carriage arrangement is then required. [0129] C) Substantial cost saving in terms of the base sheet, packaging and carriage. [0130] 3) The wall panel 1 can be line bent to form corners without the use of heat or special equipment required for 2 mm panels. This can simplify fitting and eliminate the need for edging strips around windows and at external corners. [0131] 4) It achieves a Class 1 Rating for surface spread of flame under BS 476 Part 7, compared to Class 2 for a 2 mm panel, using the same adhesion method. The improved rating makes it suitable for more demanding areas within a building.

[0132] The wall panel system further includes means for mounting wall panels 1 to a wall in accordance with the method described below. The means for mounting wall panels 1 to a wall includes double-sided adhesive tape 19 and gap filling sealant 21, typically a clear silicone gap filling sealant. Optionally, the wall panel system can include backing members, preferably in the form of backing strips 23, and/or an MS (silyl modified polyether) adhesive 25, or similar adhesive.

[0133] The double-sided adhesive tape 19 is a high-tack, high strength, tape which has been designed to provide a watertight joint, by strongly gripping onto the wall 27 and the panel 1.

[0134] The tape 19 can include a carrier layer that is water resistant, which helps to ensure that the joint is watertight. For example, the carrier layer can comprise a plastics material, and is preferably made from Polyester. The adhesive is a high performance solvent acrylic adhesive suitable for demanding applications, giving very good low and elevated temperatures. It has good resistance to chemicals and UV light.

[0135] Typical characteristics of the tape are as follows:

[0136] Tape thickness APERA 4006: 0.07 mm

[0137] Colour: Clear

[0138] Carrier material: 12 Micron Polyester

[0139] 180 Peel Adhesion AFERA 4001 10 Min: 10.7 N/25 mm

[0140] 180 Peel adhesion AFERA 4001 24 hrs: 14.2 N/25 mm

[0141] Dynamic shear adhesion ASTM D-1200 10 mins: 108 N/625 mm.sup.2

[0142] Static shear adhesion 23 C. 1 kg/625 mm.sup.2: 5500 Minutes

[0143] Static shear adhesion 70 C. 0.5 kg/625 mm.sup.2: 700 Minutes

[0144] Tack AFERA 4015: 4.60N/25 mm

[0145] Temperature resistance: 30 C. to 160 C.

[0146] The backing strip 23 comprises a plastics or aluminium strip. The strip typically has dimensions in following ranges: width40 mm to 100 mm, a depth0.5 to 3 mm, and lengthto match the length of the wall panels 1a,1b. A particularly preferred backing strip 23 has a width of between 50 mm and 100 mm, a depth of around 2 mm and is made from a non-plasticised PVC material. The PVC material has a density of around 1.4 g/cm.sup.3. It has been found that this type of backing strip 23 provides the required rigidity, but is relatively light and easy to handle. Tests have shown that the PVC strip 23 provides sufficient rigidity to achieve level joints, even when mounted onto brick or block work, and having a 1175 mm thick wall panel 1 mounted thereon. If the backing strip is too flexible it does not give the required support for this application. Aluminium or other thin semi rigid or rigid material could also be used for the strip.

[0147] A method of mounting wall panels 1 on a wall will now be described with reference to FIGS. 7 to 9.

[0148] FIG. 7 illustrates mounting first and second wall panels 1a,1b to a level and smooth wall 27, such as plaster board or MDF panel. A fitter applies a strip of double-sided adhesive tape 19 to the wall 27 at a location where first longitudinal edges 29a,29b of the first and second wall panels are to be positioned side by side. Typically, the strip of double-sided tape 19 is arranged substantially vertically on the wall, and is arranged to run along substantially the full length of the edges 29a,29b of the wall panels. Additional strips of double-sided adhesive tape 19 can be applied to the wall 27 in the vicinity of other edges of the first and second wall panels 1a,1b to ensure all edges are firmly bonded to the wall 27, and/or in the vicinity of edges of at least one additional wall panel. Typically each strip of tape 19 is oriented substantially vertically or horizontally on the wall 27. In some applications, strips of double-sided adhesive tape 19 can be located on the wall 27 in the vicinity of central portions of the first and second wall panels 1a,1b. The use of double-sided adhesive tape ensures that the bond thickness is substantially uniform, where used.

[0149] Typically adhesive 25 is not used in this context since its thickness cannot be precisely controlled.

[0150] Optionally, the tape 19 can include a guide line, which is located centrally and runs longitudinally along the tape to aid positioning of the wall panels. The guide line can be manufactured into the tape 19, or can be applied by the fitter. Additionally, or alternatively, the guide line can be applied to the wall surface. Turning back a short length of a protective cover from the top and bottom of the tape reveals the line marked on the wall.

[0151] The first wall panel 1a is mounted on the wall 27 such that the first edge 29a adheres to the strip of double-sided adhesive tape 19 along the full length of the wall panel. If available, the guideline is used to position the edge 29a of the first panel 1a. The second wall panel 1b is mounted on the wall 27 such that the first edge 29b adheres to the strip of double-sided adhesive tape 19 along the full length of the wall panel 1b. Thus the edges 29a,29b are arranged substantially parallel to one another, typically with a small gap in between. The gap is typically in the range 0.1 mm to 1.2 mm, for example in the range 0.4 mm to 1.0 mm. The gap may vary a little along the edges 29a,29b, for example if at least one edge 29a,29b has been cut by the fitter, manufacturing tolerances and/or mounting tolerances. Ideally the gap should be minimised to hide the joint.

[0152] A roller with a hard surface is preferably used to apply pressure to both adjoining edges 29a,29b in order to ensure that they are firmly adhered to the double-sided tape 19 and are level with each other.

[0153] A bead of sealant 21 is applied along the tape 19 to fill the gap between the wall panels.

[0154] The sealant 21 is immediately smoothed off, for example by wiping with at a cloth, tool or finger to improve the outer appearance.

[0155] The process is repeated for each additional joint that is required.

[0156] FIG. 8 illustrates the first and second wall panels 1a, 1b mounted onto an uneven wall in a similar manner to that described for FIG. 4.

[0157] FIG. 9 illustrates a modified method for mounting wall panels 1a,1b to a non-smooth wall 27, for example a brick wall. In the arrangement shown, a layer of adhesive 25 is applied to the wall to fill any gaps where mortar 31 sits between bricks 33. A backing strip 23 is then bonded to the wall 27 using the adhesive 25. The backing strip 23 runs longitudinally behind the joint. Double-sided tape 19 is applied to the backing strip along the length of the joint and wall panels 1a,1b are mounted on the wall 27 by bonding edges 29a,29b to the adhesive tape. Sealant 21 is applied in the gap between the wall panels 1a,ab. The sealant 21 substantially fills the gap.

[0158] The process is repeated for each additional joint required.

[0159] In each case, when the sealant 21 sets, it prevents the ingress of water into the joint. It is has a similar visual appearance to the textured surface 17 of the film, which makes the joint more difficult to see the joint. The slightly cloudy appearance of the clear sealant helps to obscure the base layer 3 from casual observation.

[0160] Furthermore the thickness of surface film is important particularly where a printed surface is involved. The print will normally be applied to a base layer 3, which is coloured white. The edge 29a,29b of the white base layer 3 will be visible if any gap is left between abutting panels 1a,1b. For this reason it is desirable that both panel edges 29a,29b should be as straight as possible and pushed as closely together as possible. They should also be the same height where possible (see FIG. 7). If there is a variation in height greater than the thickness of the clear top layer, even if the edges are perfectly abutted, white will show, highlighting the join. (FIG. 8).

[0161] To mitigate this problem, it is beneficial to use a thicker film 7 than prior art films since the margin of error for avoiding this problem is increased significantly. This is illustrated in Table 4 below.

TABLE-US-00004 TABLE 4 Film Margin For Base Layer Thickness Total Error (%) Thickness (BLT) (FT) Thickness (FT/BLT)*100 2000 m (Prior Art) 60 2060 3 2000 m (Prior Art) 100 2100 5 2000 m (Invention) 175 2175 8.8 1000 m (Invention) 175 1175 17.5

[0162] It can be seen from Table 4 above that applying the film 7 to a thinner base layer 3 increases the margin for error in concealing the white edges 29a,29b of the base layer 3. It also allows a fractionally larger gap between the wall panel edges 29a,29b before the white base layer 3 is visible.

[0163] The overall effect of the wall panel system is to provide wall panels 1a, 1b where the joins between panels are substantially undetectable by the casual viewer.

[0164] It will be appreciated by the skilled person that the invention is not limited to the described embodiments and includes variations which are within the scope of the appended claims. For example, the base layer 3 can be made from other thermoplastics such as ABS (Acrylonitrile Butadiene Styrene). While ABS is not as fire retardant as PVC, by laminating a PVC film to the ABS the flammability and surface spread of flame is reduced.

[0165] The protective film 7 can have a laminated structure. For example, the film 7 can comprise an inner PVC layer and an outer polymethyl methacrylate (PMMA) layer. PMMA is often referred to as acrylic. In one example, the PVC layer can have a thickness of around 240 m, and the acrylic layer can have a thickness of around 60 m, giving a total thickness of around 300 m.

[0166] The protective film 7 can be made from polyvinylidene fluoride (PVDF).

[0167] Additionally, or alternatively, an image can be printed on to the film 7.

[0168] Additionally, or alternatively, an image can be printed on to the adhesive layer.