You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     The present invention is directed to methods and apparatus for cladding structures to create a simulated tile or brick wall appearance. 
     Although framed buildings may be erected relatively cheaply and quickly in comparison with buildings constructed using conventional brick-laying techniques, the appearance of a conventional brick building is often preferred. The present proposal concerns a method of simulating a brick wall, and may be employed to clad a wall of a framed building or other structure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a dimensioned vertical section through a tile support, 
     FIG. 2 is a dimensioned vertical section through a single tile used to simulate a brick, 
     FIG. 3 is a vertical section through tiles supported on tile supports, 
     FIG. 3A is a view similar to FIG. 3 but showing a modified construction of tile and tile support, and 
     FIG. 4 is a front elevation showing an array of tiles simulating a brick wall to illustrate pip spacing. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, a tile support is formed by folding a metallic strip into the cross-sectional shape shown. The strip may be formed from aluminium, aluminium alloy or other suitable materials. Considering the strip to extend horizontally with its horizontal centre line perpendicular to the plane of the paper, it will be seen to have a downwardly inclined flange  3  along its upper edge and a horizontal flange  5  along its lower edge. 
     Both flanges extend from what will be regarded herein as the front side of the support. The flange  3  terminates in a depending lip  4 . The flange  5  terminates in a depending hook-shaped profile  6 , which defines a channel  8  opening upwardly on its rear side. The web  9  of the strip has a horizontal score line  10  to facilitate drilling screw holes. Pips  12  are pressed upwards from the flange  5  at intervals. At least one of the flanges is sprung relative to the web. 
     The support may be cut to the same length as the wall to be clad, or a plurality of supports may be arranged end to end. 
     A tile to be mounted on the support is of generally rectangular shape in elevation (as shown in FIG.  4 ). The tile may be manufactured from clay, cement or synthetic materials. Considering the tile to extend horizontally with its horizontal centre line perpendicular to the plane of the paper, it has the vertical cross-sectional shape shown in FIG.  2 . The main body portion  20  of the tile has a front surface  22  which is dimensioned to correspond to the major dimensions of the brick to be simulated. A first flange  24  extends upwardly from the body  20  throughout the length of the tile with the front face of the flange spaced rearwardly from the tile face  22 . The flange  24  terminates in an upper edge  25  and its rear surface is bevelled where it meets edge  25 . A rib  26  extends horizontally the length of the rear side of the tile at a position spaced from the lower edge of the tile equal to approximately one-third of the height of front face  22 . The rib is shaped to define an undercut groove  28  in its lower surface. A groove  30  is defined between the flange  24  and rib  26 . The tile extends downwards from the rib  26  to terminate in a lower, horizontal edge  32 . The rear faces of the flange  24  and rib  26  lie in the same plane. It is not essential for the flange  24  and rib  26  to extend the length of the tile and each may be of discontinuous form, so as to constitute spaced ribs. 
     The preferred vertical cross-sectional dimensions of the tile and tile support are indicated in FIGS. 1 and 2 in millimetres purely by way of example. The horizontally extending edges of the tile are rounded and bevelled as shown to facilitate hanging. 
     Referring now to FIG. 3, a wall or other support surface is clad by first fixing to it rows of the tile supports shown in FIG. 1, one above the other, with the lip  4  of an upper support interfitting with the groove  8  of the support immediately below it. Conveniently the supports are fitted into place one after another by screws or bolts  40  screwed into the wall and passed through holes drilled in the webs of the supports along the line  10 . After one support is fixed into place, the lip  4  is interfitted with the groove  8  of the next adjacent support which is then similarly screwed or bolted into place, assuming that the supports are fitted starting from the bottom of the wall. It is of course possible to fix the supports in reverse order, starting at the top of the wall and ending at the bottom. 
     The tiles may be fitted by offering up the flanges  24  of the lowest row of tiles to the groove  42  defined by the profile  6  and web  9 . The flange  24  of each tile may be used to press the flange  3  upwards to allow the bottom of rib  26  to be moved past the pips  12  and bring the tiles into the position shown in FIG.  3 . In this position the head  41  of screw or bolt  40  is received within the groove  30 , and the pips  12  are received within the groove  28  and restrain the tile against slipping out. Flange  3  provides a spring force which presses the tile downwards. The adjacent rows of tiles are vertically spaced from one another by the conventional distance used in brick laying, as are the tiles in each row. The tiles do not contact one another, but the body portion of each tile projects downwards so as to overlap the flange  24  of the tile or tiles immediately below it and the overlying interfitting portions of the supports. The gaps between the tiles may be pointed in the ordinary way. 
     Each of the pips  12  may have a length of 10 mm, and the inter-pip spacing may be selected to give the most suitable result. FIG. 4 illustrates the relationship between tiles and pips at various different possible inter-pip spacings ranging from 50 mm to 115 mm, the optimum spacing being 95 mm. A greater spacing risks insufficient support for the row of tiles, whereas lesser spacing involves unnecessary working of the strip. Instead of using pips to retain the tiles it is possible to provide the flange  5  with a continuous bead, but this involves the risk of water accumulating behind the bead. 
     FIG. 3A is a view similar to FIG. 3 but showing modified tiles and strips. In particular, the flange  24  is shorter and the lower edge  32  of the tile is closer to the rib  26  than in the case of the tile shown in FIGS. 2 and 3. In consequence, the lower edge  32  of each tile is at substantially the same level or slightly above the upper edges  25  of the flanges  24  of the tiles in the next adjacent tower row. This arrangement facilitates removal and replacement of damaged tiles. To take account of the fact that there is a reduced gap between the groove  28  of each tile and the upper edges  33  of the tiles in the next adjacent lower row, the hook-shaped profiles  6  of the strips are also made shorter. 
     Compared with existing systems, the present invention provides a superior method of simulating conventional brick walls. In particular, the invention provides the following advantages: 
     (a) a mechanical fixing for the tiles so as to eliminate weather-reliant processes such as bonding, 
     b) weather-proofing of the support surface prior to fixing of the tiles, 
     c) removability of individual tiles if damaged, 
     d) good impact-resistance as a result of the thickness of the tiles and their intimate contact with the support structure, 
     e) installation by unskilled labour because the tile supports are self-aligning and accurate measurements do not need to be taken, and 
     f) location of each tile within the tile support is independent of other tiles so that the system can accommodate the tolerances inherent in the manufacture of clay components. 
     Substantially the entire area of that part of the support surface to be clad with tiles is covered with the interlocking tile supports. This procedure increases the speed at which a building may be clad. Moreover, because the supports are made from metal and interfit so as to leave no openings through which water may penetrate, they cooperate to provide a waterproof shield within the tile cladding. The supports may be fixed by means other than screwing, for example by nailing, clipping or fixing to projecting studs. Within the scope of the invention it is not essential for all of the tiles in a row to simulate bricks. 
     In an alternative construction, the upper edge of each tile support is unprofiled, and the lower edge is bent so as to form a flange and define the pips  12  and the sprung portion  3 , thereby to support and retain the lower edges of one row of tiles and retain the upper edges of another row of tiles. The edge of the sprung portion bears against the upper edge of the adjacent strip to prevent water penetration. The upper edges of the uppermost row of tiles may be retained by a separate retaining strip.

Summary:
A clad structure and method of cladding a structure with horizontally extending, elongate supports, each support having an upper flange with a downwardly extending lip defining an open-bottomed groove and a lower flange with a tile retention protrusion along its upper surface. The tiles have upper flanges extending upwardly from their upper edge and ribs extending horizontally along a lower region of their rear surfaces. The upper flanges are positioned into the support groove during assembly and the ribs are retained behind the retention protrusions following assembly.