Patent Publication Number: US-9850666-B2

Title: Panel system for covering a building wall

Description:
TECHNICAL FIELD 
     The embodiments disclosed herein relate generally to panel systems for covering building walls, and in particular, to panel systems that include extrusions for mounting panels to building walls. 
     INTRODUCTION 
     The following paragraphs are not an admission that anything discussed in them is prior art or part of the knowledge of persons skilled in the art. 
     U.S. Pat. No. 8,240,099 discloses an architectural panel system including a plurality of architectural panels, a first mounting extrusion attached to a first architectural panel, and a second mounting extrusion attached to a second architectural panel, as well as a first anchor clip including a first attachment configuration that enables the first mounting extrusion to be slidably attached thereto, and a second anchor clip including a second attachment configuration that enables the second mounting extrusion to be slidably attached thereto. The system also includes a panel joint filler strip. The first mounting extrusion includes a first pocket portion, and the second mounting extrusion includes a second pocket portion that is shallower than the first pocket portion. The first and second pocket portions cooperate with each other to seat the panel joint filler strip. Also disclosed are methods of installing the panel system and of replacing a damaged panel of an installed array of panels. 
     U.S. Patent Application 2009/0241451 discloses a wall panel system including a mounting bracket, a wall panel, and a clip attached to the wall panel. The clip has an engaging element that secures it to the mounting bracket. The wall panel system also includes a slot in the clip facing outwardly from the wall panel, a spline slidably positioned in the slot of the clip, and a sealing insert positioned between the mounting bracket and the spline. The sealing insert may be in the shape of an X, and may be made from polypropylene foam. The sealing insert may also have a gasket tape on one side to provide an improved seal. 
     U.S. Patent Application 2012/0096799 discloses a mounting apparatus for mounting a panel to a structure. The mounting apparatus includes a panel extrusion that attaches to a back side of the panel such that the panel extrusion is obscured behind the panel in order to show a clean surface look. A connector extrusion secures the panel extrusion to the structure for simple construction. 
     SUMMARY 
     In a first aspect, a panel system for covering a building wall is provided. The panel system may comprise at least one panel assembly and at least one connector extrusion. Each panel assembly may include a panel, at least one perimeter extrusion, and a filler strip. The panel may include a front panel wall, a side panel wall, and a first back mounting flange. The perimeter extrusion may include a panel engaging portion having a panel slot, a connector engaging portion having a connector slot, and an intermediate recess formed between the panel and connector engaging portions. The first back mounting flange may be received in the panel slot. The filler strip may be received in the intermediate recess abutting the first back mounting flange and the connector engaging portion. The connector extrusion may include a connector base mountable to the building wall, and at least one connector flange received in the connector slot of the perimeter extrusion. 
     In another aspect, a building panel for covering a building wall is provided. The building panel may comprise a front panel wall, a plurality of side panel walls extending along a perimeter of the front panel wall. and a plurality of back mounting flanges. Each back mounting flange may extend from a respective side panel wall of the plurality of side panel walls. Each back mounting flange may overhang the front panel wall. Each back mounting flange may extend in length from a first flange end to a second flange end. The plurality of back mounting flanges may include at least a first back mounting flange and a second back mounting flange. The first flange end of the first back mounting flange may include a flange protrusion received in a flange recess of the second flange end of the second back mounting flange. 
     In another aspect, a panel system for covering a building wall is provided. The panel system may comprise at least one panel assembly, and at least one connector extrusion. Each panel assembly may include a panel and at least one perimeter extrusion. Each perimeter extrusion may include a panel engaging portion connected to the panel, and a connector engaging portion having a connector slot. Each connector extrusion may include a connector base mountable to the building wall, at least one connector flange received in the connector slot of the perimeter extrusion, and a retaining arm inhibiting lateral withdrawal of the connector flange from the connector slot. 
     In another aspect, a method of forming a panel is provided. The method may comprise providing a flat panel blank having a front panel wall and a plurality of peripheral panel portions extending along a periphery of the panel blank. The front panel wall and the peripheral panel portions may bee coplanar. Each peripheral panel portion may include a side panel wall inboard of a back mounting flange. Each back mounting flange may extend in length from a first flange end to a second flange end. Each of the first and second flange ends of each back mounting flange may include at least one of a flange protrusion and a flange recess. The method may further comprise for each peripheral panel portion, folding the back mounting flange relative to the side panel wall, and folding the side panel wall relative to the front panel wall to form a U-shaped channel. The method may further comprise engaging the flange protrusions and flange recesses of adjacent flange ends of adjacent back mounting flanges. 
     In another aspect, a method of making a panel assembly is provided. The method may comprise providing a panel having a front panel wall, a side panel wall, and a back mounting flange; providing a perimeter extrusion comprising a panel engaging portion having a panel slot, a connector engaging portion having a connector slot, and an intermediate recess formed between the panel and connector engaging portions; receiving the back mounting flange in the panel slot; and receiving a filler strip in the intermediate recess abutting the back mounting flange and the connector engaging portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the present specification. In the drawings: 
         FIG. 1  is a perspective view of a panel system for covering a building wall; 
         FIG. 2  is a rear perspective view of the panel system of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the panel system of  FIG. 2  along line  3 - 3  showing a starter trip, mid-clip and half-clip for mounting panel assemblies to the building wall; 
         FIG. 4A  is a cross-sectional view of the panel system of  FIG. 2  along line  4 A- 4 A showing a mid-clip for mounting two panel assemblies to the building wall; 
         FIG. 4B  is an exploded cross-sectional perspective view of the panel system of  FIG. 4A ; 
         FIG. 5A  is cross-sectional view of a sheet of material having V-shaped grooves that define fold lines for forming a panel; 
         FIG. 5B  is cross-sectional view of the sheet of material of  FIG. 5A  folded along a first fold line; 
         FIG. 5C  is cross-sectional view of the sheet of material of  FIG. 5B  folded along a second fold line; 
         FIGS. 6A-6G  are cross-sectional views showing a method of covering a building wall using panels; 
         FIG. 7  is a cross-sectional view of a panel system for covering an inside corner of a building wall; 
         FIG. 8A  is a perspective view of a panel blank in accordance with at least one embodiment; 
         FIG. 8B  is a perspective view of the panel blank of  FIG. 8A  with peripheral panel portions bent upwardly; 
         FIG. 8C  is a perspective view a panel in accordance with another embodiment; 
         FIG. 9  is a perspective view of a perimeter extrusion in accordance with another embodiment; 
         FIG. 10  is a perspective view of a half clip in accordance with another embodiment; and 
         FIG. 11  is a perspective view of a mid clip in accordance with another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Various apparatuses or processes will be described below to provide an example of an embodiment of each claimed invention. No embodiment described below limits any claimed invention and any claimed invention may cover processes or apparatuses that differ from those described below. The claimed inventions are not limited to apparatuses or processes having all of the features of any one apparatus or process described below or to features common to multiple or all of the apparatuses described below. It is possible that an apparatus or process described below is not an embodiment of any claimed invention. Any invention disclosed below that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicants, inventors or owners do not intend to abandon, disclaim or dedicate to the public any such invention by its disclosure in this document. 
     The terms “an embodiment,” “embodiment,” “embodiments,” “the embodiment,” “the embodiments,” “one or more embodiments,” “some embodiments,” and “one embodiment” mean “one or more (but not all) embodiments of the present invention(s),” unless expressly specified otherwise. 
     The terms “including,” “comprising” and variations thereof mean “including but not limited to,” unless expressly specified otherwise. A listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms “a,” “an” and “the” mean “one or more,” unless expressly specified otherwise. 
     As used herein and in the claims, two or more parts are said to be “coupled”, “connected”, “attached”, or “fastened” where the parts are joined or operate together either directly or indirectly (i.e., through one or more intermediate parts), so long as a link occurs. As used herein and in the claims, two or more parts are said to be “directly coupled”, “directly connected”, “directly attached”, or “directly fastened” where the parts are connected in physical contact with each other. As used herein, two or more parts are said to be “rigidly coupled”, “rigidly connected”, “rigidly attached”, or “rigidly fastened” where the parts are coupled so as to move as one while maintaining a constant orientation relative to each other. None of the terms “coupled”, “connected”, “attached”, and “fastened” distinguish the manner in which two or more parts are joined together. 
     As used herein and in the claims, a first part (e.g. a flange) is said to be “received” in or by a second part (e.g. a slot) where the first part is either partially or wholly received in or by the second part, unless specifically described as being “partially received” or “wholly received” in or by the second part. 
     Referring to  FIGS. 1 and 2 , there is a panel system  10  for covering a building wall  12  such as an exterior wall of a commercial or residential building. The panel system  10  includes one or more panel assemblies  20 . As shown in  FIG. 2 , each panel assembly  20  includes a panel  30  and one or more perimeter extrusions  32  that engage the panel  30 . 
     Referring now to  FIGS. 2 and 3 , the panel assemblies  20  are mounted to the building wall  12  using one or more connector extrusions that engage the perimeter extrusions  32  of the panel assemblies  20 . For example, the connector extrusions may include a starter strip  34 , a mid-clip  36 , a half-clip  38  (shown in  FIG. 3 ), or combinations of one or more thereof. As will be described below, the starter strip  34  may be used as a starting point for mounting the panel assemblies  20  to the building wall  12 . The mid-clip  36  may be used as a joint for mounting two adjacent panel assemblies  20  to the building wall  12 . The half-clip  38  may be used as an end point for completing installation of the panel system  10 . 
     Referring now to  FIGS. 4A and 4B , each panel  30  includes a front panel wall  40 , a side panel wall  42 , and a back mounting flange  44  overhanging the front panel wall  40 . The side panel wall  42  and back mounting flange  44  may be located along each edge of the front panel wall  40 . 
     As shown, the side panel wall  42  may extend orthogonally from the front panel wall  40 , and the back mounting flange  44  may extend orthogonally from the side panel wall  42  to overhang the front panel wall  40 . The front panel wall  40  and the back mounting flange  44  may be spaced apart by a distance D, which may form an overhang slot  46  therein (shown in  FIG. 4B ). 
     In some panel mounting systems, rivets may be inserted through and connect the side walls of the panels to their perimeter extrusions. Accordingly, a hole is formed through the panel side walls into which the rivets are inserted. This may affect the weather tightness of the panel sidewalls against water and dirt penetration. Further, exposed rivet heads may be visible along the panel side walls to the detriment of the panel aesthetics. In some cases, the exposed rivet heads may rust and bleed rust residue down the panels. The panel assemblies disclosed herein may have perimeter extrusions connected to panels without rivets or other fasteners penetrating the panel sidewalls. 
     Referring to  FIGS. 4A and 4B , each perimeter extrusion  32  includes a panel engaging portion  50  for engaging the panel  30 , and a connector engaging portion  52  for engaging one of the connector extrusions  34 ,  36 , or  38 . The panel engaging portion  50  may have a panel slot  54  (shown in  FIG. 4B ) shaped to receive the back mounting flange  44  of the panel  30 . The connector engaging portion  52  may have a connector slot  56  shaped to engage one of the connector extrusions  34 ,  36 , or  38 . For example, the connector slot  56  of each perimeter extrusion  32  may be shaped to receive a connector flange  92 B of one of the mid-clip  36  (as will be described below). 
     As shown, the panel engaging portion  50  may include a first U-shaped panel engaging portion  60 , which may define the panel slot  54  for receiving the back mounting flange  44  of the panel  30 . The first U-shaped panel engaging portion  60  may be defined by two opposed intermediate walls  61 ,  62  that are interconnected by an intermediate extension  64 . 
     The panel engaging portion  50  may also include a second U-shaped panel engaging portion  70  for engaging the panel  30 . In particular, the second U-shaped panel engaging portion  70  may engage the overhang slot  46 . For example, the second U-shaped panel engaging portion  70  may abut an interior panel surface that extends along the back mounting flange  44 , the side panel wall  42 , and the front panel wall  40  of the panel  30 . 
     The second U-shaped panel engaging portion  70  may be joined to the first U-shaped panel engaging portion  60 . For example, the second U-shaped panel engaging portion  70  may be defined by the intermediate wall  62  and an opposing panel-side outer wall  72  that are interconnected by a panel-side extension  74 . As shown, the second U-shaped panel engaging portion  70  may face opposite to the first U-shaped panel engaging portion  60  (e.g. to form an S-shaped profile). 
     The connector engaging portion  52  may include a U-shaped connector engaging portion  80  defining the connector slot  56 . The U-shaped connector engaging portion  80  may be defined an intermediate flange  82  and an opposing connector-side outer wall  84  that are interconnected by a connector-side extension  86 . 
     The connector engaging portion  52  may be joined to the panel engaging portion  50  (e.g. via an integral joint between the connector-side extension  86  and the intermediate wall  61 ). 
       FIG. 9  shows a perimeter extrusion  900  in accordance with another embodiment, where like part numbers refer to like parts in the previous figures. 
     Referring now to  FIGS. 4A and 4B , each connector extrusion (such as the mid-clip  36 ) includes a connector base  90  mountable to the building wall  12 . The connector base  90  may be a planar wall. 
     Each connector extrusion (such as the mid-clip  36 ) also includes one or more connector flanges shaped to fit in the connector slot  56  of a corresponding perimeter extrusion  32 . For example, in  FIGS. 4A and 4B , the mid-clip  36  includes a first connector flange  92 A extending away from the connector base  90  along a first direction for mounting a first panel assembly  20 A to the building wall  12 , and a second connector flange  92 B extending away from the connector base  90  opposite to the first direction for mounting a second panel assembly  20 B to the building wall  12 . Each connector flange  92 A,  92 B may be joined to the connector base  90  via respective connector sidewalls  94 A,  94 B. 
     In some embodiments, the connector extrusion (e.g. the mid-clip  36 ) may include a connector retaining arm  96  for engaging the connector engaging portion  52  of the perimeter extrusion  32 . As shown, the connector retaining arm  96  may extend laterally away from the first connector sidewall  94 A (e.g. along the same direction as the first connector flange  92 A). Furthermore, the connector retaining arm  94  may be located between the connector base  90  and the first connector flange  92 A. As shown, the connector retaining arm  94  may have a lip  98  that engages (e.g. hooks onto) the connector-side outer wall  84  of the perimeter extrusion  32 . This may permit connector retaining arm  96  to inhibit lateral withdrawal of the connector flange  92 A from connector slot  56 . 
     Referring to  FIG. 4A , the connector extrusion (e.g. the mid-clip  36 ) may include a retention slot  106  sized and shaped to receive connector engaging portion  52 . As shown, retention slot  106  may be defined by retaining arm  96  and connector flange  92 A. Retention slot  106  may extend laterally from a closed inboard end  108  to an open outboard end  110 . As illustrated, inboard end  108  may be defined by connector sidewall  94 A from which connector flange  92 A and retaining arm  96  may extend laterally outwardly. Retention slot  106  may receive connector-side outer wall  84  of connector engaging portion  52 . 
     Lip  98  of retaining arm  94  may be positioned outboard of the outboard end  110  of retention slot  106 . As shown, lip  98  may extend transverse to retention slot  106  toward connector flange  92 A to obstruct withdrawal of connector-side outer wall  84  from retention slot  106 . In some embodiments, when connector engaging portion  52  is received in retention slot  106  as shown, lip  98  may be laterally spaced apart from connector engaging portion  52  by a gap  112  to accommodate lateral thermal expansion. 
     Still referring to  FIG. 4A , in some embodiments, a fastener  114  (e.g. a screw, rivet, or bolt) may be inserted across retention slot  106  (e.g. through retaining arm  96  and connector-side outer wall  84 ) for retaining connector-side outer wall  84  in retention slot  106 . This may prevent connector extrusion  36  from sliding in the direction of extrusion (i.e. into the page of  FIG. 4A ) along perimeter extrusion  32 . In alternative embodiments, fastener  114  may be omitted so that connector extrusion  36  is freely slidable along perimeter extrusion  32 . In other words, connector engaging portion  52  may be freely movable along an extent of retention slot  106  (i.e. in the direction of extrusion). This may make installing panel assemblies  20 A and  20 B faster and more economical by saving the time, labor, and expense of adding fasteners  114 . 
       FIG. 11  shows a perspective view of a mid clip  1100  in accordance with another embodiment, where like part numbers refer to like parts in the previous figures. 
     Referring back to  FIG. 4A , each perimeter extrusion  32  may have an intermediate recess  100  located between the panel engaging portion  50  and the connector engaging portion  52 . For example, the intermediate recess  100  may be defined as an instep along the connector-side extension  86  and the intermediate flange  82  (e.g. at a location generally opposite to the intermediate wall  61 ). 
     As shown in  FIG. 4A , the intermediate recesses  100  of two adjacent perimeter extrusions  32  may cooperate to receive a filler strip  102  between the first panel assembly  20 A and the second panel assembly  20 B. The filler strip  102  might help conceal the mid-clip  36  after installation. Filler strip  102  may also help to seal the space between first and second panel assembly  20 A and  20 B against water, dirt, and/or debris. As shown, filler strip  102  may extend laterally across gap  104  between panels  30  of panel assemblies  20 A and  20 B and abut back mounting flanges  44  of each panel  30 . This may provide an enlarged area of contact between filler strip  102  and panels  30  for an enhanced seal, compared to a filler strip that contacts only the raw edges of side panel walls  42 . 
     Still referring to  FIG. 4A , intermediate recess  100  may be provided by an enlarged spacing between intermediate wall  62  and connector engaging portion  52 . When perimeter extrusion  32  is connected to a panel  30 , intermediate recess  100  may be formed as a slot between connector engaging portion  52  and back mounting flange  44 . As shown, intermediate recess  100  may be defined between intermediate flange  82  of connector engaging portion  52  and back mounting flange  44 , whereby intermediate flange  82  may define the threshold between connector slot  56  and intermediate recess  100 . 
     Referring again to  FIG. 3 , another example of a connector extrusion is the starter strip  34 . The starter strip  34  includes a connector base  190 , a connector flange  192 , and a connector sidewall  194  between the connector base  190  and the connector flange  192 . As shown, the connector flange  192  overhangs the connector base  190 . 
     Referring still to  FIG. 3 , another example of a connector extrusion is the half-clip  38 . The half-clip  38  includes a connector base  290  and a connector flange  292  that extends away from the connector base  290  along a first direction. As shown, the half-clip  38  may include a connector sidewall  294  between the connector base  290  and the connector flange  292 . 
     In some embodiments, the half-clip  38  may include a connector retaining arm  296  for engaging the connector engaging portion  52  of a perimeter extrusion  32 . The connector retaining arm  296  may extend away from the connector sidewall  294  along the same direction as the connector flange  292 , and at a location between the connector base  290  and the connector flange  292 . 
       FIG. 10  shows a half clip  1000  in accordance with another embodiment, where like part numbers refer to like parts in the previous figures. 
     Referring now to  FIGS. 5A, 5B and 5C , each panel  30  may be formed from a sheet of material  500  having a first fold line  502  between the front panel wall  40  and the side panel wall  42 , and a second fold line  504  between the side panel wall  42  and the back mounting flange  44 . As shown, the fold lines  502 ,  504  may be formed as generally V-shaped grooves along the sheet of material  500 . 
     The panel  30  may be formed by bending the sheet of material  500  along the second fold line  504  in the direction of arrow  510  (as shown in  FIG. 5A ), and then by bending the sheet of material  500  along the first fold line  502  in the direction of arrow  512  (as shown in  FIG. 5B ). 
     Referring to  FIG. 5C , the panel  30  may be an aluminum composite material having a core  520  located between two layers of aluminum  522 ,  524 . The core  520  may be a plastic such as polyethylene or another material. In other embodiments, the panel  30  could be made from other materials such as solid aluminum. 
     In some embodiments, the panel  30  may have a front coating  530 , which may cover exterior facing surfaces of panel  30  such as the front panel wall  40 , the side panel wall  42 , and the back mounting flange  44 . The front coating  530  may be applied before or after folding the sheet of material  500  to form the panel  30 . 
     In some embodiments, the front coating  530  may be paint, a laminate, an anodized layer, or another type of coating. For example, with reference to  FIG. 1 , the front coating may be applied as a textured coating  532  or a smooth coating  534 . 
     Referring now to  FIGS. 6A-6G , there is a method of covering a building wall with panels. 
     With reference to  FIG. 6A , the method may include step  610  of securing a first connector extrusion to a panel assembly. For example, this may include inserting the first connector flange  92 A of a mid-clip  36  into the connector slot  56  of a first perimeter extrusion  32 A on a first panel assembly  20 A. The method may include securing the mid-clip  36  to the first panel assembly  20 A using one or more fasteners  612  such as screws, rivets, or snap connectors. The fastener  612  may extend through the retaining arm  96  of the mid-clip  36 , the connector-side outer wall  84  of the first perimeter extrusion  32 A, and the first connector flange  92 A of the mid-clip  36 . 
     As shown in  FIG. 6A , the method may also include assembling the first panel assembly  20 A. For example, the method may include securing one or more perimeter extrusions  32 A,  32 B secured to the panel  30  using one or more fasteners  614  such as screws, rivets, or snap connectors. The fasteners  614  may extend through the intermediate walls  61 ,  62  of the perimeter extrusions  32 A,  32 B, and the back mounting flange  44  of the panel  30 . In other embodiments, the first panel assembly  20 A may be pre-assembled. 
     With reference to  FIG. 6B , the method may include step  620  of fastening a second connector extrusion to the building wall. For example, this may include fastening the starter strip  34  to the building wall  12  using one or more fasteners  622  such as screws, bolts, or nails. The fasteners  622  may extend through the connector base  190  and into the building wall  12 . 
     With reference to  FIG. 6C , the method may include step  630  of mounting the panel assembly to the second connector extrusion that is mounted to the building wall. For example, this may include interconnecting the connector slot  56  of a second perimeter extrusion  32 B with the connector flange  192  of the starter strip  34  (e.g. by sliding the first panel assembly  20 A onto the starter strip  34 ). 
     With reference to  FIG. 6D , the method may include step  640  of fastening the first connector extrusion to the building wall. For example, this may include securing the mid-clip  36  to the building wall  12  using one or more fasteners  642  such as screws, bolts, or nails. The fasteners  642  may extend through the connector base  190  and into the building wall  12 . 
     With reference to  FIG. 6E , the method may include step  650  of securing a third connector extrusion to a second panel assembly. For example, this may include inserting the connector flange  292  of a half-clip  38  into the connector slot  56  of a first perimeter extrusion  32 A on a second panel assembly  20 B (which may be pre-assembled or unassembled). The method may include securing the half-clip  38  to the second panel assembly  20 B using one or more fasteners  652  such as screws, rivets, or snap connectors. The fastener  652  may extend through the retaining arm  296  of the half-clip  38 , the connector-side outer wall  84  of the first perimeter extrusion  32 A, and the connector flange  292  of the half-clip  38 . 
     With reference to  FIG. 6F , the method may include step  660  of mounting the second panel assembly to the first connector extrusion that is mounted to the building wall. For example, this may include interconnecting the connector slot  56  of a second perimeter extrusion  32 B on the second panel assembly  20 B with the second connector flange  92 B of the mid-clip  36  (e.g. by sliding the second panel assembly  20 B onto the mid-clip  36 ). 
     With reference to  FIG. 6G , the method may include step  670  of fastening the third connector extrusion to the building wall. For example, this may include securing the half-clip  38  to the building wall  12  using one or more fasteners  672  such as screws, bolts, or nails. The fasteners  672  may extend through the connector base  290  and into the building wall  12 . 
     In some embodiments, steps  650 ,  660 ,  670  may be completed a plurality of times using one or more mid-clips  36  instead of the half-clip  38 . Generally, the last panel assembly is mounted to the building wall  12  using one or more half-clip  38 . This may help provide a clean or finished look. 
     Referring now to  FIG. 7 , there is another panel system  710  for covering a building wall  712 . The panel system  710  is similar in some respects to the panel system  10 , and where appropriate, similar elements are given similar reference numerals incremented by seven hundred. For example, the panel system  710  includes two panel assemblies  720 A,  720 B mounted to the building wall  712  using one or more connector extrusions (e.g. a mid-clip  736 ). Furthermore, each panel assembly includes a panel  730 A,  730 B and one or more perimeter extrusions  732 A,  732 B. 
     In this example, the panel system  710  is installed on an inside corner of the building wall  712 . Accordingly, the second panel assembly  720 B may be oriented at an angle (e.g. orthogonal) to the first panel assembly  720 A. This may result in a modified mounting configuration compared to the previous embodiments. 
     For example, while both panel assemblies  720 A,  720 B are mounted to the mid-clip  736 , the second panel assembly  720 B has a modified assembly. In particular, the panel  730 B has a front panel wall  740 B and a side panel wall  742 B, and the perimeter extrusion  732 B engages the side panel wall  742 B (i.e. the side panel wall  742 B is received in the panel slot  754 B of the perimeter extrusion  720 B). 
     While the one edge of the second panel assembly  720 B that extends along the inside corner of building  712  may be configured in this way, the remaining edges of the second panel assembly  720 B may be configured similar fashion to the previous embodiments. For example, the other edges of the second panel assembly  720 B may include a back mounting flange, which may be received within a panel slot of a corresponding perimeter extrusion. 
     Reference is now made to  FIG. 8C , where like part numbers refer to like parts in the previous figures, and where another embodiment of a panel  800  is shown. Panel  800  is similar to panel  30  in many respects, except for example the connecting corner features of panel  800 . 
     As shown, adjacent back mounting flanges  44  of panel  800  may have mating features for joining those back mounting flanges  44  together. This may provide an enhanced connection between the back mounting flanges  44  against separation. For example, in a pair of adjacent back mounting flanges  44 , at least one of the back mounting flanges  44  may include a recess sized to receive a corresponding protrusion of the other back mounting flange  44 . 
     Still referring to  FIG. 8C , each back mounting flange  44  extends in length from a first flange end  804  to a second flange end  808 . In the illustrated embodiment, the first flange end  804  of one back mounting flange  44  abuts the second flange end  808  of another mounting flange  44  at each panel corner  812  of panel  800 . At each panel corner  812 , at least one of the flange ends  804  or  808  may include a flange protrusion  816  which is received in a mating flange recess  820  of the abutting flange end  804  or  808 . In some embodiments, there may be one flange protrusion  816  and one flange recess  820  at each panel corner  812  as shown. In other embodiments there may be a plurality of flange protrusions  816  received in mating flange recesses  820  at one or more corners  812 . In some embodiments, each panel corner  812  may include the same number of flange protrusions  816  and recesses  820 , as shown. In other embodiments, one or more of panel corners  812  may include a different number of flange protrusions  816  and recesses  820  than one or more of the other panel corners  812 . 
     Flange protrusions  816  and flange recesses  820  may have any suitable shapes. In the illustrated example, flange protrusions  816  have a round bulbous shape (like a puzzle piece), and flange recess  820  have a corresponding bulbous shape (like a puzzle piece). In other embodiments, flange protrusions  816  and flange recesses  820  may have any other suitable shape(s), such as square, triangular, or another regular or irregular shape. In the example shown, flange recesses  820  have the negative shape profile as the mating flange protrusion  816 . In alternative embodiments, a flange recess  820  may have a different shaped compared to the mating flange protrusion  816 . 
       FIGS. 8A-8C  show steps in a method of forming panel  800  in accordance with at least one embodiment. Starting with  FIG. 8A , a flat panel blank  824  may be formed including a front panel wall  40  and a plurality of peripheral panel portions  828  which extend along the panel blank periphery  832 . Each peripheral panel portion  828  includes a side panel wall  42  inboard of a back mounting flange  44 . 
     Flat panel blank  824  may be formed in any suitable fashion such as by machining, casting, or stamping for example. In some embodiments, fold lines  502  and  504  may be formed between front panel wall  40 , side panel wall  42 , and back mounting flange  44  as described above with respect to  FIGS. 5A-5C . The front panel wall  40  and the peripheral panel portions  828  may be co-planar so that panel blank  824  is flat. 
     Turning now to  FIG. 8B , each back mounting flange  44  may be rotated relative to the respective side panel wall  42  and front panel wall  40 . For example, each back mounting flange  44  may be folded in direction  510  about fold line  504  to 90 degrees relative to the side panel wall  42  of the same peripheral panel portion  828 . 
     Turning now to  FIG. 8C , each side panel wall  42  may be rotated relative to front panel wall  40 . For example, each side panel wall  42  may be folded in direction  512  about fold line  502  to 90 degrees relative to front panel wall  40 . As shown, this may engage flange protrusions  816  with flange recesses  820  at panel corners  812 . The back mounting flange  44 , side panel wall  42  and front panel wall  40  form U-shaped channels. 
     While the above description provides examples of one or more apparatus, methods, or systems, it will be appreciated that other apparatus, methods, or systems may be within the scope of the claims as interpreted by one of skill in the art. 
     Items 
     
         
         Item 1. A panel system for covering a building wall, the panel system comprising:
       a) at least one panel assembly, each panel assembly including:
           i) a panel having a front panel wall, a side panel wall, and a first back mounting flange;   ii) at least one perimeter extrusion, each perimeter extrusion including
               a panel engaging portion having a panel slot, the first back mounting flange received in the panel slot,   a connector engaging portion having a connector slot, and   an intermediate recess formed between the panel and connector engaging portions; and   
               iii) a filler strip received in the intermediate recess abutting the first back mounting flange and the connector engaging portion; and   
           b) at least one connector extrusion, each connector extrusion including a connector base mountable to the building wall, and at least one connector flange received in the connector slot of the perimeter extrusion.   
     
         Item 2. The panel system of item 1, wherein the side panel wall extends orthogonally from the front panel wall and the first back mounting flange extends orthogonally from the side panel wall to overhang the front panel wall. 
         Item 3. The panel system of any one of items 1-2, wherein the panel engaging portion includes a first U-shaped panel engaging portion defining the panel slot. 
         Item 4. The panel system of any one of items 1-3, wherein the panel engaging portion includes a second U-shaped panel engaging portion engaging an interior panel surface that extends along the first back mounting flange, the side panel wall, and the front panel wall of the panel. 
         Item 5. The panel system of any one of items 1-4, wherein the connector engaging portion includes a U-shaped connector engaging portion defining the connector slot. 
         Item 6. The panel system of item 5, wherein the filler strip is received in the intermediate recess abutting the first back mounting flange and the U-shaped connector engaging portion that defines the connector slot. 
         Item 7. The panel system of item 5, wherein the U-shaped connector engaging portion comprises an intermediate flange defining a threshold between the connector slot and the intermediate recess. 
         Item 8. The panel system of any one of items 1-7, wherein the connector extrusion is a starter strip that includes a connector sidewall between the connector base and the connector flange, and wherein the connector flange overhangs the connector base. 
         Item 9. The panel system of any one of items 1-7, wherein:
       the at least one panel assembly includes a second panel assembly, and   the at least one connector flange includes a second connector flange received in the connector slot of the perimeter extrusion of the second panel assembly.   
     
         Item 10. The panel system of item 9, wherein for each of the connector flanges, the connector extrusion comprises a connector sidewall extending between the connector base and that connector flange. 
         Item 11. The panel system of any one of items 1-10, wherein:
       the connector extrusion includes a connector retaining arm,   the connector retaining arm and the connector flange defining a retention slot, and   the connector engaging portion of the perimeter extrusion is received in the retention slot.   
     
         Item 12. The panel system of any one of items 1-11, wherein:
       the panel further comprises a second back mounting flange,   each back mounting flange extends in length from a first flange end to a second flange end, and   the first flange end of the first back mounting flange includes a flange protrusion received in a flange recess of the second flange end of the second back mounting flange.   
     
         Item 13. A building panel for covering a building wall, the building panel comprising:
       a front panel wall;   a plurality of side panel walls extending along a perimeter of the front panel wall; and   a plurality of back mounting flanges,
           each back mounting flange extending from a respective side panel wall of the plurality of side panel walls,   each back mounting flange overhanging the front panel wall,   each back mounting flange extending in length from a first flange end to a second flange end,   the plurality of back mounting flanges including at least a first back mounting flange and a second back mounting flange, and   the first flange end of the first back mounting flange including a flange protrusion received in a flange recess of the second flange end of the second back mounting flange.   
           
     
         Item 14. The building panel of item 13, wherein each side panel wall extends orthogonally to the front panel wall. 
         Item 15. The building panel of any one of items 13-14, wherein each back mounting flange extends orthogonally to the respective side panel wall. 
         Item 16. The building panel of any one of items 13-15, wherein each flange end of each back mounting flange is adjacent the first or second flange end of another back mounting flange forming an adjacent pair of flange ends. 
         Item 17. The building panel of item 16, wherein in each adjacent pair of flange ends, a flange protrusion of one flange end is received in a flange recess of another flange end. 
         Item 18. The building panel of any one of items 13-15, wherein the flange protrusion is shaped to mate with the flange recess. 
         Item 19. The building panel of item 18, wherein a shape of the flange recess is the negative of a shape of the flange protrusion. 
         Item 20. A panel system for covering a building wall, the panel system comprising:
       a) at least one panel assembly, each panel assembly including:
           i) a panel; and   ii) at least one perimeter extrusion, each perimeter extrusion including
               a panel engaging portion connected to the panel, and   a connector engaging portion having a connector slot; and   
               
           b) at least one connector extrusion, each connector extrusion including
           a connector base mountable to the building wall,   at least one connector flange received in the connector slot of the perimeter extrusion, and   a retaining arm inhibiting lateral withdrawal of the connector flange from the connector slot.   
           
     
         Item 21. The panel system of item 20, wherein:
       the connector extrusion includes a retention slot defined by the retaining arm and the connector flange, and   the connector engaging portion is received in the retention slot.   
     
         Item 22. The panel system of item 21, wherein:
       the retention slot extends laterally from a closed inboard end to an open outboard end; and   the retaining arm includes a lip positioned outboard of the outboard end of the retention slot and which extends transverse to the retention slot toward the connector flange.   
     
         Item 23. The panel system of item 22, wherein:
       the connector includes a connector sidewall extending from the connector base,   the connector flange and the retaining arm extend from the connector sidewall, and   the connector sidewall defines the closed inboard end of the retention slot.   
     
         Item 24. The panel system of any one of items 22-23, wherein:
       the lip is laterally spaced apart from the connector engaging portion of the perimeter extrusion.   
     
         Item 25. The panel system of any one of items 21-24, wherein:
       connector engaging portion is freely movable along an extent of the retention slot.   
     
         Item 26. A method of forming a panel, the method comprising: 
         providing a flat panel blank having a front panel wall and a plurality of peripheral panel portions extending along a periphery of the panel blank,
       the front panel wall and the peripheral panel portions being coplanar,   each peripheral panel portion including a side panel wall inboard of a back mounting flange,   each back mounting flange extending in length from a first flange end to a second flange end,   each of the first and second flange ends of each back mounting flange including at least one of a flange protrusion and a flange recess.   
     
         for each peripheral panel portion, folding the back mounting flange relative to the side panel wall, and folding the side panel wall relative to the front panel wall to form a U-shaped channel; and 
         engaging the flange protrusions and flange recesses of adjacent flange ends of adjacent back mounting flanges. 
         Item 27. The method of item 26, wherein: 
         said folding the back mounting flange relative to the side panel wall comprises folding the back mounting flange to 90 degrees relative to the side panel wall. 
         Item 28. The method of any one of items 26-27, wherein: 
         said folding the side panel wall relative to the front panel wall comprises folding the side panel wall to 90 degrees relative to the front panel wall. 
         Item 29. The method of any one of items 26-28, further comprising: 
         for each peripheral panel portion, forming a first fold line between the side panel wall and the front panel wall. 
         Item 30. The method of item 29, wherein: 
         said folding the side panel wall relative to the front panel wall comprises folding the side panel wall along the first fold line. 
         Item 31. The method of any one of items 26-30, further comprising: 
         for each peripheral panel portion, forming a second fold line between the side panel wall and the back mounting flange. 
         Item 32. The method of item 31, wherein: 
         said folding the back mounting flange relative to the side panel wall comprises folding the back mounting flange along the second fold line. 
         Item 33. A method of making a panel assembly, the method comprising: 
         providing a panel having a front panel wall, a side panel wall, and a back mounting flange; 
         providing a perimeter extrusion comprising a panel engaging portion having a panel slot, a connector engaging portion having a connector slot, and an intermediate recess formed between the panel and connector engaging portions; 
         receiving the back mounting flange in the panel slot; and 
         receiving a filler strip in the intermediate recess abutting the back mounting flange and the connector engaging portion. 
         Item 34. The method of item 33, wherein the side panel wall extends orthogonally from the front panel wall and the first back mounting flange extends orthogonally from the side panel wall to overhang the front panel wall. 
         Item 35. The method of any one of items 33-34, further comprising: 
         providing a connector extrusion having a connector base and at least one connector flange; and 
         receiving the connector flange in the connector slot of the perimeter extrusion. 
         Item 36. The method of item 35, further comprising: 
         fastening the connector base to a building wall.