Building cladding systems

Abstract

An elongate mounting rail (6) for a closed, brick slip cladding system for a building, the mounting rail having two elongate, substantially parallel edges, a substantially planar plate (14) extending between the two edges and an elongate brick slip retaining rail (16) which in cross-section has a stem (16a) with a foot at one end which is fixed to the plate and, at the other end, two arms (16b, 16c) extending away from the stem to give the retaining rail a generally T-shaped configuration, in which the stem extends away from the plane of the plate, and the outermost ends of the arms of the retaining rail form two elongate, substantially parallel edges which are substantially parallel to the elongate edges of the mounting rail, one of the elongate edges of the mounting rail being formed as a male engaging edge and the other of the elongate edges of the mounting rail being formed as a complementary female engaging edge, whereby two parallel mounting rails may be aligned next to and parallel to each other with their plates substantially parallel and their abutting male and female engaging edges brought together so as to form a closed joint between the two mounting rails.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to systems for cladding buildings with brick slips.BACKGROUND ART

[0002] Many buildings are now designed with structural walls of reinforced concrete or some other strong but not aesthetically attractive material which are then given a more aesthetically attractive façade with the appearance of bricks by cladding them with brick slips or tiles; these are not only aesthetically pleasing, but also considerably lighter than a normal brick. A brick slip, or brick tile, may be thought of as a thin brick which is mounted in a similar orientation as is a rectangular tile, with horizontal upper and lower edges (usually the long edges of the rectangle) vertical side edges (usually the short edges of the rectangle) and an aesthetically attractive outer surface; the brick slip is a simple rectangle in cross-section and has two elongate kerfs or slots running along its long upper and lower edges to engage with brick-carrying rails forming a framework of horizontal mounting rails (in cross-section, these brick slips resemble a letter H, and are shown in GB2586832, for example). The framework is attached to the structural wall, and the brick slips are put onto the mounting rails, which are configured to support the brick slip in the vertical plane, and to restrict its movement in the horizontal direction towards / away from the building; the brick slips are supported in rows, with small distances between adjacent brick slips in a row and between adjacent rows; these distances are subsequently filled with mortar to give the appearance of a conventional brick wall, with the brick slips in adjacent rows being sized and located relative to the brick slips in adjacent rows so that the cladding resembles conventional brick walls laid in Common bond, English bond or Flemish bond, or in other bond patterns. Other forms of brick slip, usually known as brick tiles, have more complicated cross-sectional shapes which may not need slots, but in general these brick tiles are not as straightforward to manufacture or install as brick slips, they require mounting rails which are more complicated in shape, and as a result such systems are more expensive than those with H-shaped brick slips.

[0003] In some buildings the cladding is mounted directly to, or very closely to, the outer surface of the structural wall. Where there is a spacing between the inner surface of the cladding and the outer surface of the structural wall, the mounting framework may be in the form of a ventilated, or open lattice; this allows the brick slips to "breathe", allowing air within the spacing to flow through them to the ambient atmosphere, and vice versa, which helps prevent condensation and water damage to the cladding materials. Often the spacing between the inner surface of the cladding and the outer surface of the structural wall is filled with a thermally insulating material to improve the thermal performance of the building. In such a system, it is very undesirable for there to be any flow of air through the brick slips, because this could allow air to pass through the cladding and feed a fire burning in or passing along the spacing between the inner surface of the cladding and the outer surface of the structural wall; accordingly it is now required that the framework supporting the brick slips be "closed", i.e. to be airtight (indeed, before new building cladding systems are approved for use they are expected to pass pressure tests showing the level to which they are airtight, and to be approved they must reach a predetermined level of airtightness). In this application, the term "closed" is used in relation to cladding systems to denote systems which are intended to be sufficiently airtight to meet statutory building standards, and the term "open" is used in relation to ventilated cladding systems. At present, cladding systems using H-shaped brick slips utilise open frameworks, as in GB2586832 for example, whilst closed systems are provided using brick tiles with more complicated cross-sectional shapes, as in GB2371314 for example.SUMMARY OF THE INVENTION

[0004] The present invention is predicated on the realisation that combining certain features of known closed and open cladding systems can provide a closed cladding system which has the simplicity and low cost of conventional open systems, whilst providing additional benefits in ease of manufacture and cladding system assembly.

[0005] The present invention therefore provides an elongate mounting rail for a closed, brick slip cladding system for a building, the mounting rail having two elongate, substantially parallel edges, a substantially planar plate extending between the two edges and an elongate brick slip retaining rail which in cross-section has a stem with a foot at one end which is fixed to the plate and, at the other end, two arms extending away from the stem to give the retaining rail a generally T-shaped configuration in cross-section, in which the stem extends away from the plane of the plate, and the outermost ends of the arms of the retaining rail form two elongate, substantially parallel edges which are substantially parallel to the elongate edges of the mounting rail, one of the elongate edges of the mounting rail being formed as a male engaging edge and the other of the elongate edges of the mounting rail being formed as a complementary female engaging edge, whereby two parallel mounting rails may be aligned next to and parallel to each other with their plates substantially parallel and their abutting male and female engaging edges brought together so as to form a closed joint between the two mounting rails.

[0006] Such an arrangement is specifically intended for a closed cladding system (as described above), and allows the mechanical fixing of brick slips in a row, so that another row can be fixed above it; one mounting rail is fixed to a support structure or framework for supporting the cladding a predetermined distance away from the building outer wall, and another is mounted the appropriate distance above it, then a brick slip is manoeuvred so that its top kerf sits at an angle to the plane along the downwardly extending arm of the retaining rail of the upper mounting rail, the brick slip is raised at an angle and then its bottom edge pushed towards the wall so that the bottom kerf is located over the upstanding arm of the retaining rail of the lower mounting rail, the brick slip is then lowered so that it sits on the stem of the retaining arm of the lower mounting rail and is restrained from moving towards or away from the plane of the plate by the interaction of the arms in the kerfs. The complementary male and female engaging edges are configured to form an airtight closed joint when engaged and mounted on a building. The arrangement therefore enables a closed cladding structure system to be assembled using conventional H-shaped brick slips, quickly and simply, and therefore at low cost. In addition, and as will be explained, the arrangement provides an airtight seal between adjacent mounting rails thus improving fire protection, the profile of the mounting rail allows the brick slips to be correctly positioned relative to the plane of the plate, and the cladding may be easily assembled onsite or prefabricated offsite.

[0007] It should be understood that when the term "plane" is used in relation to the plate part of the mounting rail, this plane is usually substantially parallel to the outer wall of the building to which the cladding is mounted. When the term cross-section is used herein, this cross-section is orthogonal to the above plane, so that the plane corresponds to a coronal plane and the cross-section is the view taken looking perpendicularly towards the sagittal plane.

[0008] The mounting rail preferably has a shape in cross-section which is substantially constant along the length of the mounting rail. This allows the mounting rail to be manufactured easily, by extruding aluminium or aluminium alloy, for example.

[0009] The plate has flat inner and outer surfaces, with the female engaging edge preferably extending perpendicularly away from the outer surface by a predetermined distance so as to locate a brick slip relative to the arms of the retaining rail so that an edge of the retaining rail is accurately located within a slot or kerf in the brick slip. The slot along one or both long edges of the brick slip is preferably wider than the retaining rail arms which fit therein; this allows the brick slip to be manoeuvred so that an arm is partially located within one slot and then slanted inwardly and upwardly / downwardly to locate the arm of the retaining rail of the adjacent mounting rail to be located in the slot along the other slot. The predetermined distance is also preferably the same as or greater than the length of the head of a fixing (such as a bolt) for attaching the mounting rail to the supporting framework; the former option allows the top surface of the fixing to assist in positioning the brick slip, the latter option allows a bolt fastened through the plate not to impinge against an inner surface of a brick slip positioned on the mounting rail.

[0010] The size of the male engaging edge in a direction perpendicular to the plane of the plate is preferably less than the size of the complementary female engaging edge within which the male engaging edge engages. This allows the two edges to be located for assembly initially at an angle to the plane and, once the male edge is partially inserted into the female edge, the mounting rail can be rotated to be parallel to the building wall and then moved in that plane so as to align the mounting rail with the supporting framework. This makes it easy for an operator to orientate and locate one mounting rail, usually a long piece of metal, on top of one which has already been mounted to the support framework. Aligning the mounting rail with the supporting framework allows the fixings / bolts to be inserted easily for mounting the upper mounting rail in the correct position relative to the mounting rail beneath it. The male engaging edge may be formed on the uppermost of the edges of the mounting rail in use, which means that the open female engaging edge in use faces downwardly, so does not act as a trap for water or dirt; alternatively, the male engaging edge may be formed on the lowermost of the edges of the mounting rail.

[0011] One of the two arms forming the top of the T shaped retaining rail may be longer than the other, which facilitates the insertion of a brick slip between two mounting rails. The uppermost arm on a retaining rail may be shorter than the lowermost arm on that retaining rail; this arrangement means that the brick slip when mounted between two retaining rails is secured at its bottom by friction with the stem on which it rests and the upstanding short arm, and secured at its top by the downwardly extending arm of the retaining rail of the mounting rail above.

[0012] Preferably the stem of the T-shaped retaining rail where it meets the planar plate is not perpendicular to the plane. It is advantageous if the stem is initially, adjacent the plate, angled upwardly slightly and then has a bend so that the remainder of the stem is horizontal; the horizontal part of the stem supports the brick slip in the correct orientation, while the angled portion allows the stem as a whole to flex slightly due to the elasticity of the material of which it is made, which is useful in accommodating inaccuracies in alignment between mounting rails and also in enabling easier insertion of a brick slip. Accordingly, in use the stem of the T-shaped retaining rail where it meets the planar plate may be angled upwardly, and has a portion further from the plate which is substantially horizontal.

[0013] One side of the stem of the T shape and / or the top of the T shape may have elongate grooves. Such grooves are helpful in increasing friction between the retaining rail and the brick slip mounted on it, and also for allowing mortar to key in to.

[0014] Suitably, the mounting rail is a unitary item, formed in a single piece by a process such as extrusion. The mounting rail is preferably metallic, such as aluminium or aluminium alloy.

[0015] The invention also provides a kit of parts including two or more mounting rails as previously defined and two elongate rails of L-shaped cross-section, one having an elongate edge formed as a male engaging edge and the other having an elongate edge formed as a complementary female engaging edge. These rails act as top and bottom rails, and can be used to end a vertical run of mounting rails; this may be required where there is a window ledge, lintel or the like around an opening in the wall. Alternatively, the cladding may be provided in prefabricated form, with a number of mounting rails being fixed together to form a panel of several mounting rails which can be mounted to the wall (via a support structure or framework) as one.

[0016] The kit of parts may further include support rails for connecting to the plate on its surface opposite to that from which the retaining rail extends to hold the mounting rails a predetermined distance from a building wall. Additionally or alternatively the kit of parts may further include support brackets for fixing the support rails to the building wall.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The invention will now be described by way of example and with reference to the accompanying figures, in which; Figure 1 is a perspective view of a section of wall cladding incorporating mounting rails in accordance with the invention; Figure 2 is a cross-sectional view of the three different types of rails shown in Figure 1, and Figures 2a and 2b are enlarged views of the male and female engagement edges of the rails in Figure 2; Figure 3 is an exploded perspective view of the three rails of Figure 2; Figure 4 is a side elevation of two mounting rails and the top and bottom rails of Figure 2 in assembled form and showing brick slips mounted thereon in three rows; Figure 5 is a perspective view of a section of wall cladding incorporating mounting rails in accordance with the invention similar to Figure 1 but incorporating a window opening to show the support structure for fixing the mounting rails to a building outer wall, and Figures 6(a) to 6(c) are front elevation, plan and side elevation views of the section of wall cladding of Figure 1, showing the support structure of Figure 5 more clearly. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Figure 1 shows a section of assembled wall cladding comprising 5 horizontal rows or courses of brick slips 2. Each slip has two kerfs, or slots 4 cut into its two thin, longitudinal faces - the upper and lower faces of the brick slips when installed. The middle three courses of brick slips 2 are located between two horizontally-oriented mounting rails 6, whilst the top course is located between the uppermost mounting rail 6 and a top rail 8, and the bottom course is located between the lowermost mounting rail 6 and a bottom rail 10. The spaces between adjacent rows of brick slips 2 and adjacent brick slips in a single row are filled with mortar 12, as in a conventional brick wall. The section of cladding illustrated is attached to a building structural wall (not shown, but to the right of the drawing).

[0019] Figure 2 shows the profiles (i.e. cross-sections) of the three different types of rail shown in Figure 1. The mounting rail 6 has a flat rear plate portion 14 which is planar and in use is fixed with its plane parallel to the building wall (not shown, but to the right of the drawing). The mounting rail 6 is also provided with an outwardly (to the left in the drawing) extending retaining rail 16 which is generally T-shaped with a stem 16a, and an upwardly extending arm 16b and a downwardly extending arm 16c, the arm 16b being slightly longer than the arm 16c. The stem 16a is not straight, but extends upwardly at an angle away from the plate 14 before bending to the horizontal adjacent the arms 16b, 16c; the upper surface of the stem 16a has elongate grooves (as shown in Figure 3), as do the outer faces of the arms 16b, 16c, for improving friction between these faces and the brick slip 2, and for assisting mortar to key into position.

[0020] The upper edge 18 of the plate 14 of the mounting rail 6 is provided with a male engaging profile and the lower edge of the plate 14 of the mounting rail 6 is provided with a female engaging profile 20; the male and female profiles extend along the length of the mounting rail, and are complementarily shaped to engage with each other as will be described below. Figures 1 and 2 also show a top rail 8 and a bottom rail 10; these two rails are generally L-shaped but have a retaining lip 8a, 10a extending downwardly and upwardly, respectively, which engage in the kerfs 4 in the brick slips 2 in the top and bottom rows, and aid in locating and retaining a brick slip in the correct position. As can be seen more clearly in the enlarged views in Figures 2a and Figure 2b, the top and bottom rails 8, 10 also have a planar part 14', which in use is substantially coplanar with plate 14, and an L-shaped extension 22a, 22b. The L-shaped extension 22a on the top rail 8 in Figure 2a has a horizontal portion 24a and a vertical portion 26a which is parallel to part 14'; extension 22a together with the lower part of plate 14' forms a cup-shaped socket which extends longitudinally along the rail 8. The socket has a substantially constant inner width W1, and a substantially constant outer width W2. The L-shaped extension 22b on the bottom rail 10 in Figure 2b has a horizontal portion 24b and a vertical portion 26b (the outer and inner surfaces of which are parallel to part 14') which terminates at its upper end in a rounded lug (in cross-section) 28; lug 28 extends longitudinally along the rail 8. There is a substantially constant distance W3 between the inner surface of the plate 14' and the outer surface of the vertical portion 26b, and lug 28 has a substantially constant width W4, so that the horizontal distance between the inner edge of the lug 28 and the inner surface of the part 14' is W5 (so, W3 = W4 + W5). The male and female profiles 18,20 of the mounting rail 6 are substantially the same as those of the bottom and top rails 10, 8, and the male and female profiles 18, 20 are complementary so that adjacent male and female edges can be joined together by engaging a male profile 18 with a female profile 20.

[0021] The socket and lug 8 forming female and male edges respectively engage together to form an airtight seal running along the join between two adjacent rails, as is shown in Figure 4. The dimensions of the male and female profiles are chosen so that W3 is a little less than W1 (so that the rails can be brought together and the lug 28 located easily in the cup, and so that the rails can be rotated slightly relatively to each other around the lug, adding the fixing of the rails in the correct vertical position) and so that W5 is the same as or a little less than the thickness of the downwardly extending part 14' (i.e. W5 equals or is less than ½(W2 - W1) - assuming all parts of the female profile have constant thickness). The latter arrangement ensures that, when assembled with their planar surfaces coplanar as shown in Figure 4, the upstanding arm 26b and lug 28 "pinch" the downwardly extending part 14' between the lug 28 and the support structure 30 (shown schematically in Figure 4). The dimension W1 is chosen relative to the lengths of the stem 16a and of the horizontal portions of the top and bottom rails 8, 10 so that when assembled with brick slips 2 as shown in Figure 4, the arms 16b, 16c and the retaining lips 8a, 10a all fit within the kerfs 4; also, the size of dimension W1 is sufficient to engage with the rear surface of the brick slip 2 to push it outwardly so that it sits in the correct horizontal position, and also sufficient to accommodate the head of a bolt as shown in Figure 4.

[0022] Figure 3 is a perspective view of the rails 6, 8, 10 shown in Figure 2, and shows the elongate grooves formed in the upper surface of the stem 16a and in the outer faces of the arms 16b, 16c which extend along the length of the retaining rail 16. It also shows an outwardly extending lug, or nib, 17 at the top of the upwardly extending arm 16b which runs along the length of the retaining rail 16; this nib is sized so as to help locate arm 16b in the kerf 4 on the lower edge of the brick slip 2. A similar nib runs along the upper edge of the retaining lip 10a of the bottom rail 10.

[0023] Figure 4 shows a cladding section comprising three rows of brick slips 2, two mounting rails 6 and a top rail 8 and a bottom rail 10, all as described above; the rails 6, 8, 10 are connected to a support structure 30 (shown schematically in this Figure) by bolts or screws 32 with their heads 34 not quite in contact with the reverse inner face of the brick slips 2. Holes are provided in the planar plates 14 of the mounting rails and the planar parts of the top and bottom rails 8, 10 for the bolts / screws 32 to pass through and also through holes in the support structure 30; the holes are aligned so that, when assembled, there is no contact between the lug 28 and the horizontal portion 24a, but instead they are vertically spaced; this allows for thermal expansion and contraction of the aluminium rails without affecting the airtight seal created between the male and female engaging profiles 18, 20 as described above.

[0024] Figures 5 and 6 shows the same arrangement of five rows of brick slips 2 as in Figure 1 and Figure 5 illustrates how the cladding system can be modified to accommodate a window or other hole in the building support structure; all of the elements of the fixing system described above can be seen in these drawings. Figures 5 and 6 also show the framework support system (which is conventional) in more detail. The upper right hand corner of the section of cladding illustrated has been cut away in Figure 5 to form a rectangular opening; the mounting rails 6 and top and bottom rails 8, 10 have been attached by bolts 32 to a vertical support 36 which is L-shaped as shown in Figure 6b and which in turn is bolted to a number of brackets 38 (only one is shown in Figures 5, 6b and 6c); each bracket is L-shaped and has a flange 38a for bolting to the building wall and a second flange 38b for mounting / bolting to the vertical support 36.

[0025] It will of course be understood that many variations may be made to the above-described embodiment without departing from the scope of the present invention. For example, the male profiles 18 could extend downwardly and the female profiles upwardly (the reverse of what is illustrated), the brick slips could be replaced with tiles provided these had top and bottom kerfs and at least a rear face which was flat, the brick slips could be halved in length so as to provide a façade with any of the various conventionally-used bricklaying bond patterns, and differently sized mounting rails could be provided for use with brick slips having kerfs on their short edges so as to mount a row of vertically-orientated brick slips as is commonly done above window and door lintels. An outwardly extending nib, similar to nib 17, may be provided at the top of vertical portion 26a of L-shaped extension 22a, and / or elongate grooves similar to those provided on the retaining rail 16 may be provided on the outer surface of vertical portion 26a of L-shaped extension 22a to assist in locating the brick slip.

[0026] Where different variations or alternative arrangements are described above, it should be understood that embodiments of the invention may incorporate such variations and / or alternatives in any suitable combination.

Claims

1. A mounting rail for a closed, brick slip cladding system for a building, the mounting rail having two elongate, substantially parallel edges, a substantially planar plate extending between the two edges and an elongate brick slip retaining rail which in cross-section has a stem with a foot at one end which is fixed to the plate and, at the other end, two arms extending away from the stem to give the retaining rail a generally T-shaped configuration in cross-section, in which the stem extends away from the plane of the plate, and the outermost ends of the arms of the retaining rail form two elongate, substantially parallel edges which are substantially parallel to the elongate edges of the mounting rail, one of the elongate edges of the mounting rail being formed as a male engaging edge and the other of the elongate edges of the mounting rail being formed as a complementary female engaging edge, whereby two parallel mounting rails may be aligned next to and parallel to each other with their plates substantially parallel and their abutting male and female engaging edges brought together so as to form a closed joint between the two mounting rails.

2. A mounting rail according to Claim 1, in which the cross-sectional shape of the mounting rail is substantially constant along its length.

3. A mounting rail according to Claim 1 or Claim 2, in which the plate has flat inner and outer surfaces, in which the female engaging edge extends perpendicularly away from the outer surface by a predetermined distance so as to locate the brick slip relative to the arms of the retaining rail so that an edge of the retaining rail is accurately located within a slot or kerf in the brick slip.

4. A mounting rail according to any of Claims 1 to 3, in which the size of the male engaging edge in a direction perpendicular to the plane of the plate is less than the size of the complementary female engaging edge within which the male engaging edge engages.

5. A mounting rail according to any preceding claim, in which in use the mounting rail is mounted horizontally, and in which the male engaging edge is formed on the uppermost of the edges of the mounting rail.

6. A mounting rail according to any preceding claim, in which in use the mounting rail is mounted horizontally, and in which the one of the two arms forming the top of the T shaped retaining rail is longer than the other.

7. A mounting rail according to Claim 6, in which the uppermost arm is shorter than the lowermost arm.

8. A mounting rail according to Claim 6 or Claim 7, in which the stem of the T-shaped retaining rail where it meets the planar plate is not perpendicular to the plane.

9. A mounting rail according to Claim 8, in which in use the stem of the T-shaped retaining rail where it meets the planar plate is angled upwardly, and has a portion further from the plate which is substantially horizontal.

10. A mounting rail according to any preceding claim, in which one side of the stem of the T shape and / or the top of the T shape has elongate grooves.

11. A mounting rail according to any preceding claim, in which the mounting rail is a unitary item, formed in a single piece.

12. A kit of parts including two or more mounting rails according to any preceding claim, and two elongate rails of L-shaped cross-section, one having an elongate edge formed as a male engaging edge and the other having an elongate edge formed as a complementary female engaging edge.

13. A kit of parts according to Claim 12, further including support rails for connecting to the plate on its surface opposite to that from which the retaining rail extends to hold the mounting rails a predetermined distance from a building wall.

14. A kit of parts according to Claim 13, further including support brackets for fixing the support rails to the building wall.

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