The present invention relates to a building cladding system and method for cladding at least part of a building structure.

The outer surface of many buildings may have eroded and deteriorated to such a degree that it is necessary to provide a remedy which will extend their life. Such buildings may be high rise buildings which may be privately owned.

The remedy may comprise attaching cladding panels to the outer skin of such buildings. Such cladding panels can also improve thermal insulation. Housing associations may use cladding panels to clad many of their buildings to increase their thermal efficiency so as to meet new regulations. To attach the cladding panels to such a building generally requires scaffolding. However, the cost of hiring, erecting and decommissioning scaffolding is expensive and may exceed 50% of the total works cost.

An object of the present invention is to provide a building cladding system which can be installed without requiring scaffolding and an associated method.

According to one aspect of the present invention, there is provided a building cladding system comprising a plurality of cladding panels and a plurality of mounting rails,

each cladding panel having a major plane and being configured to interengage with at least one other adjacent like panel and at least one said mounting rail, the panel having: two major side surfaces which are at least substantially parallel to the major plane and four edge surfaces substantially forming a perimeter of the panel, a panel-to-panel engaging means first portion at one said edge surface, a panel-to-panel engaging means second portion at one said edge surface, and a panel-to-rail engaging means first portion arranged to be retractably extendable relative to one said major side surface and be adjacent to one said edge surface;

each mounting rail being configured for fixing to a building structure, each rail having a panel-to-rail engaging means second portion; whereby the panel-to-panel engaging means first portion of one said cladding panel is latchingly engagable with a panel-to-panel engaging means second portion of an adjacent said like cladding panel so that the major planes of the two panels, when interengaged, are substantially coplaner, and whereby the panel-to-rail engaging means first portion of each said cladding panel is latchingly engagable with the panel-to-rail engaging means second portion of one said rail to secure the panel to the mounting rail.

The building cladding system is of a lightweight construction and the system may be installed by a technician abseiling or suspended from a position above the work area. The panel-to-panel and panel-to-rail engaging means may be simply operated by the technician using a key to secure the cladding panels to each other and to the mounting rails.

As no scaffolding is required for the building cladding system according to the invention, there is a significant cost reduction for installing the cladding. Also, as scaffolding is not required, work can be started at short notice. Once cladding is completed, no scaffolding is required to be decommissioned, and there would be very little mess to clear up afterwards.

The cladding panels of the building cladding system can be purpose built to provide an outer finishing system and contributes to the integrity of the building. The cladding panels can provide one or more of weather proofing, thermal insulation, fire resistance, and sound proofing. The cladding panels may also be decorative. The building cladding system is structurally sound and requires minimum maintenance.

The panel-to-panel engaging means second portion of the building cladding system may include a recess in said edge surface. The panel-to-panel engaging means second portion may have a bar in said recess. The panel-to-panel engaging means first portion is preferably arranged to be selectively extendable from said edge surface. The panel-to-panel engaging means first portion may be retractably extendable from said edge surface. The panel-to-panel engaging means first portion may include a camming mechanism for latchingly engaging the bar. The panel-to-rail engaging means second portion may include an opening or recess. The panel-to-rail engaging means second portion may have a bar in said opening. The panel-to-rail engaging means first portion may comprise a camming mechanism for latchingly engaging the bar.

The camming mechanism of the panel-to-panel engaging means first portion and/or the panel-to-rail engaging means first portion may comprise a camlock mechanism. The camlock mechanism is preferably an over-centre camlock mechanism

One major side surface of the cladding panel may have access means for providing access for a tool to operate the panel-to-panel engaging means first portion. One edge surface of the cladding panel may have access means for providing access for a tool to operate the panel-to-rail engaging means first portion.

At least one of said panel-to-panel engaging means first portion and said panel-to-panel engaging means second portion is preferably situated at each said edge surface.

One major side surface may have a recess or a rebate for receiving at least a portion of a said mounting rail.

According to another aspect of the present invention, there is provided a method of cladding at least part of a building structure, comprising the steps of: providing a plurality of cladding panels and a plurality of mounting rails, each cladding panel having a major plane and being configured to interengage with at least one other adjacent like panel and at least one mounting rail, the panel having: two major side surfaces which are at least substantially parallel to the major plane and four edge surfaces substantially forming a perimeter of the panel, a panel-to- panel engaging means first portion at one said edge surface, a panel-to-panel engaging means second portion at one said edge surface, and a panel-to-rail engaging means first portion arranged to be retractably extendable relative to one said major side surface and be adjacent to one said edge surface, each rail having a panel-to-rail engaging means second portion;

fixing the mounting rails to the building structure; latchingly engaging the panel-to-rail engaging means first portion of a first said cladding panel with the panel-to-rail engaging means second portion of a first said mounting rail to secure the first panel to the first mounting rail at least;

latchingly engaging the panel-to-rail engaging means first portion of a second said cladding panel with the panel-to-rail engaging means second portion of a second said mounting rail to secure the second panel to the second mounting rail at least; and

latchingly engaging the panel-to-panel engaging means first portion of said second cladding panel with the panel-to-panel engaging means second portion of said first cladding panel so that the major planes of the two panels, when interengaged, are substantially coplaner.

A plurality of said cladding panels may be secured to one said mounting rail.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:- Figures 1 and 2 are perspective views of a cladding panel for a building cladding system in accordance with one embodiment of the invention with an outer insulation layer omitted for illustrative purposes;

Figure 3 is a perspective view of a camming hook mechanism for the cladding panel;

Figure 4 is a horizontal sectional view of part of two adjacent cladding panels secured to each other next to a wall showing panel-to-panel engaging means;

Figure 5 is a sectional view taken along line A-A of Figure 4;

Figure 6 is a view similar to Figure 4 wherein one cladding panel is secured to a mounting rail of the building cladding system which is fixed to the wall showing panel-to-rail engaging means;

Figure 7 is a sectional view taken along line B-B of Figure 6;

Figure 8 is a perspective view of the mounting rail;

Figure 9 is a perspective view of a wall of a building partially clad with the cladding system according to the invention; Figure 10 is a rear view of a person installing the mounting rail on the wall;

Figures 1 1 and 12 are a rear view and a side view, respectively, of a person installing the cladding panel; and

Figure 13 is a vertical cross-section through the panel-to-panel engaging means connecting the top edge of a first panel secured to the bottom edge of an adjacent second panel situated above the first panel, the panels being adjacent to a wall.

Referring to Figures 1 to 9 of the accompanying drawings, a cladding panel 1 of the building cladding system 100 is generally rectangular in elevation and has a first major side surface 2 and a second major side surface 3 (shown for example in Figures 4 and 6) which are parallel to a major plane of the panel 1 . The cladding panel 1 also has opposed first and second side edge surfaces 4, 5 interconnected by opposed first and second end edge surfaces 6, 7 defining a surrounding perimeter edge. The first major side surface is formed by an outer surface of a board 8 which is mounted on a perimeter frame 9. The perimeter frame 9 has opposed first and second side frame portions 10, 1 1 interconnected by opposed first and second end frame portions 12, 13. The first end frame portion 12 extends between the first and second side frame portions 10, 1 1. The second end frame portion 13 extends fully beneath the first side frame portion 10 and partly beneath the second side frame portion 1 1. The second end frame portion 13 is divided into two equal parts 14. The space inside the perimeter frame 9 is divided into two equal parts by a partition rail 15 extending between the first and second end frame portions 12, 13 and situated between the first and second side frame portions 10, 1 1. These two equal parts are filled with insulation 17. The insulation

17 in each part may be in the form of a rigid or semi-rigid insulation member.

The cladding panel 1 has an additional layer of insulation 18 (shown in Figures 4 and 6 but omitted from Figures 1 and 2) covering the opposite side of the perimeter frame 9 to the board 8 except for a surface 19 of the second side frame portion 1 1 distal from the board 8 so that a rebate 20 is defined by the second side frame portion 1 1 and the insulation 18. An external face of the additional layer of insulation 18 distal from the board 8 forms the second major side surface 3 of the cladding panel 1 .

The first side frame portion 10 has three panel-to-panel engaging means first portions 21 spaced along and retractably extendable from the first side edge surface 4 of the cladding panel 1 . The first end frame portion 12 has two panel-to-panel engaging means first portions 21 spaced along and retractably extendable from the first end edge surface 6 of the cladding panel 1 .

Each panel-to-panel engaging means first portion 21 has a camming hook mechanism or over-centre camlock mechanism 22 which is shown in Figure 3. The mechanism 22 has a mounting 23 which includes a pair of mounting flanges 60 at the base of the mounting 23 for receiving fixings. A hook or latch 24 of the mechanism 22 is rotatably mounted about an axis 61 through the mounting 23. The hook 24 has a hexagonal hole 62 centred on the axis 61 for receiving a suitable tool, such as an Allen key, and the hook 24 also has a camming surface 63.

A slot or recess 26 (see Figure 5) is provided in the respective edge surface 4, 6 of the cladding panel 1 and the over-centre camlock mechanism 22 is mounted in the recess 26. The first major side surface 2 of the panel 1 has a hole 25 to provide access for the tool to be inserted into the hexagonal hole 62 to rotate the hook 24 relative to the mounting 23. The slot 26 is of a sufficient length in order to fully contain the hook 24 when the hook 24 is rotated by the tool so as to be unlocked and fully retracted ensuring that personnel and other cladding panels 1 cannot be damaged by protruding hooks 24. A suitable camming hook mechanism or over-centre camlock mechanism 22 is described in

US 6409235.

The second side frame portion 1 1 has three panel-to-panel engaging means second portions 27 on the second side edge surface 5 of the cladding panel 1 . The second end frame portion 13 has two panel-to-panel engaging means second portions 27 on the second end edge surface 7 of the cladding panel 1 .

The three panel-to-panel engaging means second portions 27 of a first cladding panel 1 a are positioned in a second side frame portion 1 1 such that they are aligned with corresponding panel-to-panel engaging means first portions 21 of an adjacent second panel 1 b when the first and second panels 1 a, 1 b are brought together in a coplanar manner with the first side frame portion 10 of the second panel 1 b confronting, and being coincident with, the second side frame portion 1 1 of the first panel 1 a. Likewise the two panel-to- panel engaging means second portions 27 of a third cladding panel 1 c above the first panel 1 a are positioned in the second edge frame portion 13 such that they are aligned with corresponding panel-to-panel engaging means first portions 21 of the adjacent first panel 1 a below when the first and third panels are brought together in a coplanar manner with the second edge frame portion 13 of the third panel 1 c confronting, and being coincident with, the first edge frame portion 12 of the first panel 1 a.

Each panel-to-panel engaging means second portion 27 has a slot or recess 28 in the respective edge surface 5 or 7 of the cladding panel 1 (see Figure 5). The slot or recess 28 of the panel-to-panel engaging means second portion 27 crosses a shallower recess 29 in the respective edge surface. The shallower recess 29 contains a base 30 of a U-shaped bar 31 which base 30 extends along the shallower recess 29 and across the slot 28. Distal ends 32 of legs of the U-shaped bar 31 protrude through the second side frame portion 1 1 towards an interior of the frame 9 and into a recess 33. The distal ends 32 also pass through a plate 34 in the recess 33 and nuts are screwed onto the distal ends 32 so that the U-shaped bar 31 is held onto the respective frame portion

1 1 and against a base of the shallower recess 29.

The second side frame portion 1 1 also has four panel-to-rail engaging means first portions 36 spaced along and retractably extendable from a side surface 37 of the frame portion 1 1 distal from the board 8. The panel-to-rail engaging means first portions 36 are in different parts of the second side frame portion 1 1 from the panel-to-panel engaging means second portions 27. Each panel-to-rail engaging means first portion 36 is similar to the panel-to-panel engaging means first portion 21 . However, the access hole 38 for the tool is in the second side edge surface 5 of the panel 1 . There is also a recess 39 in the second side frame portion 1 1 behind the mounting 70 of the over-centre camlock mechanism 71 of the panel-to-rail engaging means first portion 36. This recess 39 is hidden by the board 8 of the cladding panel 1 .

Referring to Figures 7 and 8, a mounting rail 42 of the building cladding system 100 comprises a channel 43 with a pair of mounting flanges 44. Each mounting flange 44 has a series of holes 45 for receiving expansion bolts 46 or other suitable fixings for fixing the mounting rail 42 to a wall 51 of a building. The mounting rail has four panel-to-rail engaging means second portions 48 spaced along it wherein each portion 48 comprises a slot 49 at the bottom of the channel 43 (i.e. the portion facing away from the wall to which the mounting rail is attached) and a bar or pin 50 extending across the inside of the channel 43 opposite the slot 49. An opening or recess comprises the slot 49 and at least a portion of the inside of the channel 43.

A method of cladding at least part of the wall 51 (see Figure 9) of a building using the cladding system 100 will now be described.

A technician initially marks the vertical position of where the mounting rails 42 are to be mounted to the wall 51 . The technician 52 (see Figure 10) abseils down the wall 51 with a mounting rail 42 which is preferably supported independently from the technician and the technician 52 drills holes in the wall 51 . Expansion bolts 46 or other suitable fixings are used to fix the flanges 44 of the mounting rail 42 to the wall 51 . This process is repeated until all the required mounting rails 42 are fixed to the wall 51 . The position of the mounting rails 42 may be aligned by, say, chalk or lasers. A template may be used. A spacer may be used to space adjacent mounting rails 42.

In Figure 9, the wall 51 of the building is shown as having a series of vertical mounting rails 42 mounted by the technician 52 spaced along it. Several mounting rails are mounted vertically in a line to form a longer vertical mounting rail.

Once the mounting rails 42 are securely attached to the wall 51 , the technician 52 abseils down the wall 51 with each cladding panel 1 (see Figures 1 1 and 12) which is preferably supported independently from the technician. A first cladding panel 1 a is positioned so that the additional layer of insulation 18 of the cladding panel 1 a is placed against the wall 51 and so that a first mounting rail 42a is received in the panel rebate 20. The technician 52 inserts a tool in the access hole 38 in the second side edge surface 5 of the panel 1 a for one of the panel-to-rail engaging means first portions 36 to rotate the hook 72 of the over-centre camlock mechanism 71 of the portion 36 so that it extends beyond the second side frame portion 1 1 and relative to the second major side surface 3. The hook 72 is received by the slot 49 in the mounting rail 42a and the cam surface 73 of the hook 72 engages the bar 50 (see Figure 7). Final travel of the tool causes the cam surface 73 of the hook 72 engaging the bar 50 to pull the cladding panel 1 a and rail 42a together with significant force ensuring that they cannot come apart without application of the tool. Thus, the panel-to- rail engaging means first portion 36 of the first cladding panel 1 a is latchingly engaged with the panel-to-rail engaging means second portion 48 of the first mounting rail 42a to secure the first cladding panel 1 a to the first mounting rail 42a. The technician 52 then inserts the tool in the access hole 38 for each of the other panel-to-rail engaging means first portions 36 so that they are latchingly engaged with corresponding panel-to-rail engaging means second portions 48 of the mounting rail 42a.

A second cladding panel 1 b is positioned by the technician 52 so that the second side frame portion 1 1 of the second cladding panel 1 b is aligned with a second mounting rail 42b, and the second cladding panel 1 b covers the access holes 38 of the first cladding panel 1 a. In the same way, the technician 52 inserts the tool in the access hole 38 in the second side edge 5 of the panel 1 b for each of the panel-to-rail engaging means first portions 36 to latchingly engage them with the corresponding panel-to-rail engaging means second portions 48 of the second mounting rail 42b to secure the second cladding panel 1 b to the second mounting rail 42b.

The technician 52 then inserts the tool in the access hole 25 in the first major side surface 2 of the second cladding panel 1 b for each of the panel-to- panel engaging means first portions 21 to rotate the hook 24 of their over-centre camlock mechanisms 22 so that they are received by respective slots 28 of the panel-to-panel engaging means second portions 27 in the second side frame portion 1 1 of the adjacent first cladding panel 1 a and the cam surface 63 of each hook 24 engages the base 30 of the U-shaped bar 31 in the shallower recess 29 (see Figure 5). Final travel of the tool causes the cam surface 63 of the hook 24 engaging the base 30 to pull the first and second cladding panels 1 a, 1 b together with significant force ensuring that they cannot come apart without application of the tool. Thus, the panel-to-panel engaging means first portions 21 of the second cladding panel 1 b are latchingly engaged with the panel- to-panel engaging means second portions 27 of the first cladding panel 1 a to secure the second cladding panel 1 b to the first cladding panel 1 a with the major planes of the two panels 1 a, 1 b being coplaner.

As well as the technician 52 locking the second cladding panel 1 b to the first cladding panel 1 a beside it, the technician locks a third cladding panel 1 c immediately above the first cladding panel 1 a (see Figure 13) by having the hook 24 of the mechanism 22 of each panel-to-panel engaging means first portion 21 of the first end frame portion 12 of the first cladding panel 1 a rotated so as to latchingly engage the base 30 of the U-shaped bar 31 of the corresponding panel-to-panel engaging means second portion 27 in the second end frame portion 13 of the third cladding panel 1 c above.

The cladding panels 1 of the building cladding system 100 are hence connected to the mounting rails 42 and to adjacent panels and each cladding panel 1 is coplanar with its adjacent cladding panels. The cladding panels 1 are thus quickly locked into position by the abseiling technician 52. A cladding panel 1 may be latchingly engaged to at least two collinear mounting rails 42 wherein at least one of the panel-to-rail engaging means first portions 36 is latchingly engaged with a panel-to-rail engaging means second portion 48 of one mounting rail 42 and at least another of the panel-to-rail engaging means first portions 36 is latchingly engaged with a panel-to-rail engaging means second portion 48 of another mounting rail.

Referring to Figure 9, where windows 53 or doors 54 are required in the wall 51 , the cladding panels 55, 55', 56 have appropriate cut outs in them which are prepositioned prior to delivery to site.

The cladding panels 57 at the left-hand side of Figure 9 are modified panels in that both side frame portions 10, 1 1 have panel-to-rail engaging means first portions 36 so that the modified panels 57 are connected to two mounting rails 42.

Alternatively, an extension member could be attached to the first side edge surface 4 of the cladding panel 1 and have panel-to-panel engaging means second portions to be engaged by the panel-to-panel engaging means first portions 21 of the first side frame portion 10 of the cladding panel 1 . The extension member would also have panel-to-rail engaging means first portions to engage the panel-to-rail engaging means second portions 48 of the mounting rail 42.

Whilst a particular embodiment has been described, it will be understood that various modifications may be made without departing from the scope of the invention.

The cladding panel 1 may have any number of panel-to-panel engaging means first and second portions 21 , 27 and panel-to-rail engaging means first portions 36, and the mounting rail 42 may have any number of panel-to-rail engaging means second portions 48.

The material of the insulation 17 and the material of the additional layer of insulation 18 may be different. The insulation 17 and the additional layer of insulation 18 may be replaced by a single piece of insulation. The over-centre camlock mechanism 22 may be replaced by any suitable form of locking mechanism and the locking mechanism may include a camlock.