Cladding assembly

Abstract

The cladding assembly comprises a plurality of prefabricated panels, having a front face, a rear face and a peripheral edge. Each panel comprising a concrete base 2, defining said rear face, and a plu

Description

FIELD OF THE INVENTION This invention relates to a cladding assembly for attachment to a supporting surface to create a structure resembling rustic natural stone, and in particular to a cladding assembly comprising a plurality of prefabricated panels and including a mechanical fastening system for attaching to panels to the supporting surface. BACKGROUND OF THE INVENTION Prefabricated panels are known for forming a fascia or cladding of a wall, such panels having a natural stone face to resemble a rustic stone wall. Such panels typically comprise a plurality of natural stones embedded in a concrete base to produce composite panels of predetermined dimensions that can be affixed to a supporting structure to provide an attractive natural stone appearance. Such known panels are typically affixed to a supporting surface by means of mortar or adhesive. This makes installation of the panels a time consuming job, requiring a considerable level of skill, and requires that the supporting structure be capable of receiving such mortar or adhesive. It also makes it impossible to subsequently remove such panels from the supporting structure without significant damage to both the panels and the supporting structure. Furthermore, new UK building code regulations require that all cladding panels installed above first floor level, or above three metres, are mechanically fixed. Most known cladding systems on the market do not have a solution for this and therefore installers have had to create one on site, with a saw and drill. NSBC will no longer accept this as they do not want modifications onsite with operators as they believe this can’t be controlled. Also, if a panel has a fixing point embedded into it during production, such fixing may be lost if the panel is cut to size or may prevent the panel from being mounted accurately enough to avoid gaps between adjacent panels. An object of the present invention is to provide a cladding assembly that can be used to create a structure resembling a natural stone wall, wherein the panels of the cladding assembly can be attached to a supporting structure via an improved mechanical fastening system. SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided a cladding assembly for forming a structure resembling a natural stone wall; said panel assembly comprising a plurality of prefabricated panels, each panel having a front face for forming a visible face of the assembled structure, a rear face and a peripheral edge, each panel comprising a concrete base, defining said rear face, and a plurality of pieces of natural stone embedded in the concrete base to form the front face of the panel; at least one mounting slot being formed in at least a portion of the peripheral edge of each panel, said at least one mounting slot being formed in the concrete base of the respective panel; and a mechanical fastening system for attaching said plurality of panels to a supporting structure, said mechanical fastening system comprising a plurality of L shaped mounting brackets, each mounting bracket comprising a planar first portion adapted to be attached to the supporting structure, and a second portion extending perpendicularly from the first portion and terminating in a mounting portion having a first part adapted to be received in a mounting slot of a first panel and a second part adapted to be received in a mounting slot of an adjacent second panel, with the mounting portion of the respective bracket being located between opposing edges of said first and second panels. In a preferred embodiment each panel has parallel first and second side edges on opposite sides of the front face thereof, a respective mounting slot being formed along the length of each of said first and second side edges, wherein, in use, with the panels mounted on a vertical supporting structure, said first and second edges define upper and lower edges of the respective panel, the mounting portions of respective mounting brackets being located between abutting upper and lower edges of adjacent panels with the first and second parts of each mounting portion of each bracket located in opposing slots of said upper and lower edges of respective adjacent panels. A portion of the peripheral edge of each panel extending from said at least one mounting slot to said rear face of the respective panel may be rebated such that the second portion of a respective mounting bracket can be received between rebated portions of opposing edges of adjacent panels with outer portions of said opposing edges in abutting contact to provide a seamless join between adjacent panels. The concrete base of each panel may comprise at least 14% by weight Portland cement and at least 3% by weight pozzolan and may comprise 36% by weight sand and 30% by weight aggregate having a particle size of between 9mm and 10mm. The sand preferably comprises ASTM C33 concrete sand. The concrete base of each panel may incorporate a polymeric fibre mesh reinforcement therein. Preferably the concrete base of each panel has no more than 3% entrapped air. Each mounting bracket may be formed in a single piece from a metal, such as aluminium and may be manufactured by an extrusion process. In a preferred embodiment the mounting portion of each bracket comprises a rectangular plate, the second portion extending along the length of a rear face of the mounting portion, said second portion extending from a central region of the mounting portion in a direction perpendicular to said rear face of said mounting portion such that said first and second parts of the mounting portion extend symmetrically from either side of said second portion of the respective mounting bracket. BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the present invention will now be described with reference to the accompanying drawings, in which:- Figure 1 is a perspective view of a cladding assembly in accordance with an embodiment of the present invention; Figure 2 is a perspective view of an upper part of the panel of the assembly of Figure 1; Figure 3 is a front perspective view of a panel of the cladding assembly of Figure 1; Figure 4 is a rear perspective view of a panel of the cladding assembly of Figure 1; Figure 5 is a perspective view of a mounting bracket of the cladding assembly of Figure 1; and Figure 7 is a perspective view showing the assembly of two panels of the cladding assembly of Figure 1. DETAILED DESCRIPTION OF THE DRAWINGS A cladding assembly for cladding a wall of a building to resemble a rustic natural stone wall finish in accordance with an embodiment of the present invention is illustrated in the drawings. The cladding assembly comprises a plurality of prefabricated panels that are attached to a supporting structure via a plurality of metal mounting brackets 10, as will be described below in more detail. Each panel has a front face for forming a visible face of the assembled structure, a rear face and a peripheral edge extending between the front and rear faces. Each panel is formed from a concrete base 2, defining said rear face, and a plurality of pieces of natural stone 4 embedded in the concrete base 2 to form the front face of the panel; at least one mounting slot 6 being formed in at least a portion of the peripheral edge of each panel, preferably in upper and lower edges of the panel. The at least one mounting slot 6 of each panel is preferably formed in the concrete base 2 of the respective panel. In the embodiment shown in the drawings, each panel has parallel upper and lower edges, a respective mounting slot 6 being formed along the length of each of said upper and lower edges. Side edges of each panel, extending between the upper and lower edges, may be stepped to facilitate interlocking of adjacent panels. Each panel may be manufactured by placing natural stone pieces into wet concrete in a frame or mould. This results in the natural stone pieces being set in the wet concrete and, once cured, the finished panel is removed from the mould and the mounting slots may be cut into the upper and lower edges of the panel. Three differently shaped types panel may be provided, as shown in Figure 1, namely a main panel A, corner panel B shaped to define a corner of the assembled structure, and a linking panel C adapted to fit between a corner panel B and a main panel A or between two main panels A, the panels being shaped to inter-fit with one another to form a continuous planar cladding over a supporting structure. As shown in Figure 5, each mounting bracket 10 comprises single piece “L” shaped metal bracket comprising a planar first portion 12 adapted to be attached to the supporting structure via a screw or bolt passing through an aperture 14 in the first portion 12, with or without adhesive, and a second portion 16 extending perpendicularly from the first portion 12 and terminating in a mounting portion 18 having a first part 20 adapted to be received in a mounting slot 6 of a first panel and a second part 22 adapted to be received in a mounting slot 6 of an adjacent second panel, with the mounting portion 18 of the respective bracket 10 being located between opposing edges of said first and second panels (as shown in Figure 7). The mounting portion 18 of each mounting bracket 10 is, in use, located between abutting upper and lower edges of adjacent panels with the first and second parts 20,22 of the mounting portion 18 located in opposing mounting slots 6 of said upper and lower edges of respective adjacent panels. By locating the mounting portion 18 of each mounting bracket 10 between opposing mounting slots 6 in abutting upper and lower edges of the panels, the position of each mounting bracket 10 with respect to the panels can be easily adjusted by sliding the mounting portion 18 of the respective bracket 10 along the respective mounting slots 6. As shown in Figure 7, a portion R of the upper and lower edge of each panel extending from each mounting slot 6 to the rear face of the respective panel is rebated such that the second portion 16 of a respective mounting bracket 10 can be received between opposing rebated portions R of opposing upper and lower edges of adjacent panels with outer portions of said opposing upper and lower edges in abutting contact to accommodate the brackets 10 between the panels and provide a seamless join J between adjacent panels. The mounting portion 18 of each bracket 10 comprises a rectangular plate, the second portion 16 of the bracket 10 extending along the length of a rear face of the mounting portion 18 and extending from a central region of the mounting portion 18 in a direction perpendicular to said rear face whereby said first and second parts 20,22 of the mounting portion 18 extend symmetrically from either side of said second portion 16 of the respective mounting bracket 10. The mounting brackets 10 may be formed from aluminium, preferably via an extrusion process. The concrete used to form the base 2 of each panel A,B,C has been specially developed by the inventors to support the loading applied to the mounting slots 6 via the brackets 10. The concrete base 2 of each panel preferably comprises at least 14% by weight Portland cement and at least 3% by weight pozzolan and comprises 36% by weight ASTM C33 concrete sand and 30% by weight aggregate having a particle size of between 9mm and 10mm. A polymeric fibre mesh reinforcement tis embedded in the base 2 of each panel for added strength. The resulting concrete base 2 of each panel A,B,C has no more than 3% entrapped air. There follows a table with a detailed composition of the concrete base of a panel in accordance with a preferred embodiment of the present invention: Concrete Mix Design (Metric) conwerstens Based on SSD (Saturated Surface is Dry] Conditions 1 Metre 35.3 7" Cement Content (sacks / cubsc meter) Sand absorption W.46 2.00½ 1 cuter meter IKg 3531 cubic feet ® 1,308 r 2.2 pounds chic yards 3 / 8“ aggregate absorption 1.10% 28.3 5 g 1 ounce Water / cement ratic- UnS weight Kg / cubic meter 0.36 2431.0 29.67 cc ar mi 341.8182 1 ounce (i^uid) kg / c.j.yd : % of tots 1 aggregate vo 1 u me Sand 48% 447 0582 Kg / cu, Meter % of tota 1 aggregate va1ume Reck 52% 10 46333 sacks / ru. Meter. 42.73 k = srrte <d rem»r.r Ingraft tents Kitograms Specific Gravity aBSftWe Volume CWFt cost rotate, volume Cement 1 (Portland) 358 3.15 0113513 0.687440851 Omerst 7 (Pomian) Sand (ASTM C33 Masonry) SSD (silica Sand) 8« SOI 2.2 2.? 0«40223 033 0.33 sand at 48% 0,36 rack at 52% 3 / 8" Rock (ASTM C33) SSD (rIver aggregate) 96S 2.7 0.337469 Water Superpfastidzer (Kg / cwt) (evetek7015 high range water reducer) Entrapped Air 129 0.1 100 cc Z 3% 1. 1 0128723 a.coai 0.03 Totals 2431.0 1 Sand 3 / 8 "Rock Absorption 2.00% Wat Weigh t -r Container Weight 800 grams 1.10% Ask the ma SCO grams nutaoturar of the aggregate for this information. Oven Dry Weight + C.c nta iner 775 gra ms 7SC grams Container Weight 100grams Wet weight zoo grams ICC grams 7GC grams Dry Weight 675 grams Moisture Content - ((WM Weight MVyWeight) / DryW 100. Total min 6§C grams % the absorption % Sand 373" Rock ;(700 - 675) / 875 * 100 = 3.7% minus the absorptfon of the Sand (2.0%)« 1.7% Free Moisture ;(700 ’ 698) / 650 * 100 - 1A5% minus the absorption of the rode (1-1%) - 035% Free Moisture The invention is not limited to the embodiment described herein but can be amended or modified without departing from the scope of the present invention as 5 defined by the appended claims.

Claims

1. A cladding assembly for forming a structure resembling a natural stone wall;said cladding assembly comprising a plurality of prefabricated panels, each panel having a front face for forming a visible face of the assembled structure, a rear face and a peripheral edge, each panel comprising a concrete base, defining said rear face, and a plurality of pieces of natural stone embedded in the concrete base to form the front face of the panel; at least one mounting slot being formed in at least a portion of the peripheral edge of each panel, said at least one mounting slot being formed in the concrete base of the respective panel;and a mechanical fastening system for attaching said plurality of panels to a supporting structure, said mechanical fastening system comprising a plurality of L shaped mounting brackets, each mounting bracket comprising a planar first portion adapted to be attached to the supporting structure, and a second portion extending perpendicularly from the first portion and terminating in a mounting portion having a first part adapted to be received in a mounting slot of a first panel and a second part adapted to be received in a mounting slot of an adjacent second panel, with the mounting portion of the respective bracket being located between opposing edges of said first and second panels, wherein the mounting portion of each bracket comprises a rectangular plate, the second portion extending along the length of a rear face of the mounting portion, said second portion extending from a central region of the mounting portion in a direction perpendicular to said rear face of said mounting portion such that said first and second parts of the mounting portion extend symmetrically from either side of said second portion of the respective mounting bracket;wherein each panel has parallel first and second side edges on opposite sides of the front face thereof, a respective mounting slot being formed along the length of each of said first and second side edges, wherein, in use, with the panels mounted on a vertical supporting structure, said first and second edges define upper and lower edges of the respective panel, the mounting portions of respective mounting brackets being located between abutting upper and lower edges of adjacent panels with the first and second parts of each mounting portion of each bracket located in opposing slots of said upper and lower edges of respective adjacent panels, a portion of the peripheral edge of each panel extending from said at least onemounting slot to said rear face of the respective panel being rebated such that the second portion of a respective mounting bracket can be received between rebated portions of opposing edges of adjacent panels with outer portions of said opposing edges in abutting contact to provide a seamless join between adjacent panels.

2. An assembly as claimed in any preceding claim, wherein the concrete base of each panel comprises at least 14% by weight Portland cement and at least 3% by weight pozzolan.

3. An assembly as claimed in claim 2, wherein the concrete base of each panel comprises 36% by weight sand and 30% by weight aggregate having a particle size of between 9mm and 10mm.

4. An assembly as claimed in claim 3, wherein said sand comprises ASTM C33 concrete sand.

5. An assembly as claimed in any preceding claim, wherein the concrete base of each panel incorporates a polymeric fibre mesh reinforcement therein.

6. An assembly as claimed in any preceding claim , wherein the concrete base of each panel has no more than 3% entrapped air.

7. An assembly as claimed in any preceding claim, wherein each mounting bracket is formed from metal and manufactured by an extrusion process.s

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