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CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/872,160, entitled “Roofing and Siding Systems for Extremely High Winds”, filed Dec. 1, 2006, which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    Embodiments of the present invention relate to metal roofing and siding systems, and more particularly to unique panel profiles for joining adjacent panels and for improved aesthetics. 
         [0004]    2. Description of Related Art 
         [0005]    Metal roofing and siding panels are typically roll-formed from long, continuous coils of pre-painted metal and are secured to structures using concealed-fastener type systems. The lateral sides of the long panels are often formed into various ribbed profiles with a wide expanse of thin sheet metal between the ribs. This expanse can have slight waves and distortion, which is commonly known in the industry as “oil canning.” One cause of this condition is the stresses and strains imparted to the metal when metal plates are cold-formed into thin gages of sheet metal. Some architects will not specify metal roofs or wall systems due to this condition. Thus, a need exists for metal panels that minimize the appearance of “oil canning.” 
         [0006]    Another visual problem that may be experienced with metal panels is distortion caused by protuberances in the subroof or wall framing that the metal panels are secured to. Welding bands, plugs, plywood corners, and misaligned frames can all distort the panels from underneath. Accordingly, there is a need in the industry to reduce the undesirable aesthetic effects of distortions in metal panels. 
         [0007]    An issue that sometimes arises in connection with metal roofing and siding systems is the penetration of moisture through the systems into the underlying structure. A cause of this penetration is often due to the location of the seams between the adjacent panels. In some designs, the seam is positioned proximate the drainage plane, which is the primary surface of the panel that water flows over. The moisture may penetrate the seam by capillary action or may be wind-driven. One solution has been to apply sealants to the seams; however, sealants can crack and fail over time. Thus, there is a need for novel joint designs that provide improved sealing and that may reduce the need for sealants. 
         [0008]    In the field, some metal roofs fail due to high wind uplift loads. In an attempt to quantify the performance of metal roofs with respect to uplift loads, standards organizations such as Underwriters Laboratories (U.L.) and the American Society for Testing and Materials (ASTM) have developed tests for wind uplift (e.g., U.L. 580; ASTM-E1592). Their tests involve placing an exemplary roofing structure in a chamber and subjecting it to wind loads. A common failure mode for these tests is that the panels are blown off the structure due to seam failure. Just prior to blow off, the wind separates the thin substantially planar sections of the panel between ribs from the structure thereby creating a “ballooning” type effect. This in turn causes the base of the ribs to spread apart, which is referred to herein as “rib spread.” This rib spread condition creates significant stress on the seams between the adjacent panels, which are located at the ribs and often causes the seam to fail and the panel to blow off the structure. A need exists in the industry to provide improved wind uplift resistance. 
         [0009]    Thermal expansion and contraction are issues experienced by all metal roofs. For example, a typical structure may have roof panels that are 100 feet long and 2 feet wide. Several panels may be joined to cover a building width of 200 feet. During a 100 degree Fahrenheit day, these exemplary panels may expand 1 9/16-inches longitudinally and 3¼ inches over the entire width of the building. The width expansion translates to 1/32 inch expansion in width for each 2 foot wide panel. A need exists in the industry for roofing and siding systems that can accommodate this type of expansion. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    The above and other needs are met by the present invention which, in one embodiment, provides a roofing or siding system configured to be positioned against a structure. The roofing or siding system includes a first panel including a female locking element opening away from the structure when positioned thereon; a second panel including a male locking element directed toward the structure when positioned thereon; and an anchor bar configured to be attached to the structure, wherein the anchor bar defines a channel directed away from the structure which is configured to engage the male locking element and further defines a flange directed towards the structure that is configured to engage the female locking element. 
         [0011]    In another embodiment, a roof or siding panel system configured to be positioned atop a structure is provided. The roof or siding panel system includes a first panel having a first lateral edge portion extending upwardly relative to the structure when the first panel is positioned thereon, wherein the first lateral edge portion includes a groove portion and an inclined portion; and a second panel having a second lateral edge portion that includes a first leg portion extending upwardly relative to the structure when the second panel is positioned thereon, and a second leg portion which is substantially parallel with the first leg and terminates in a lock flange directed towards the first leg portion, wherein the first and the second panels are configured to be adjacently positioned, and wherein the second lateral edge portion of the second panel is configured to receive the first lateral edge portion of the first panel between the first and the second leg portions such that the lock flange engages the groove portion. 
         [0012]    In a further embodiment, another roofing or siding system for attachment to a structure is provided. This roofing or siding system includes an elongate panel having two opposing lateral edge portions and an intermediate portion between the opposing lateral edges wherein the intermediate portion has a substantially convex shape when the panel is positioned on the structure; and a pair of anchor bars, each having an engagement element configured to engage a lateral edge portion of the roofing panel and wherein the pair of anchor bars are attached to the structure wherein the pair of anchor bars are substantially parallel and spaced apart a predetermined distance such that the intermediate portion remains convex when the panel is engaged by the pair of anchor bars. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         [0013]    Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
           [0014]      FIG. 1  is a partial cut-away view of a batten seam roofing system  10  in accordance with an embodiment of the present invention; 
           [0015]      FIG. 2  is a cross section view of a batten style panel  20  for use in the batten seam roofing system  10  shown in  FIG. 1 ; 
           [0016]      FIG. 3  is a cross section view of an anchor bar  30  for use in the batten seam roofing system  10  shown in  FIG. 1 ; 
           [0017]      FIG. 4  is a partial cut-away view of a batten system  45  in accordance with another embodiment of the present invention; 
           [0018]      FIGS. 5A and 5B  are side views of a panel  20  modified to accomplish a change in direction for a batten seam roofing system  10  in accordance with an embodiment of the present invention; 
           [0019]      FIGS. 5C and 5D  are side views of a batten  40  modified to accomplish a change in direction for a batten seam roofing system  10  in accordance with an embodiment of the present invention; 
           [0020]      FIG. 6  is a partial cut-away view of a standing seam roofing system  50  in accordance with an embodiment of the present invention; 
           [0021]      FIG. 7  is a cross-section view of a panel  55  for use in the standing seam roofing system  50  shown in  FIG. 6 ; 
           [0022]      FIG. 8  is a cross-section view of an anchor bar  90  for use in the standing seam roofing system  50  shown in  FIG. 6 ; 
           [0023]      FIG. 9  is a partial cut-away view of a tubular standing seam system  100  in accordance with an embodiment of the present invention; 
           [0024]      FIG. 10  is a cross-section view of a panel  105  for use in the standing seam roofing system  100  shown in  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. 
         [0026]    Various embodiments of the present invention are directed to novel metal roofing and siding systems, which address needs in the industry. Although features of various embodiments of the present invention may be applicable to any metal roofing or siding system, aspects of the present invention will be described with reference to three general design types: batten seam, standing seam, and tubular standing seam. Also, for convenience, various aspects of the invention will be described with reference to a roofing system but are applicable to siding systems as well. 
       Batten Seam Embodiments 
       [0027]      FIG. 1  is a schematic diagram of a portion of a batten seam roofing system  10  with a cut-away section illustrating how adjacent panels are secured to a structure  5  in accordance with an embodiment of the present invention. The illustrated embodiment includes two elongate panels  20 A,B, an anchor bar  30 , fasteners  38  and a batten cap  40 . 
         [0028]      FIG. 2  is a cross-section view of a panel  20  used in connection with the batten seam roofing system  10 . Panel  20  is a substantially elongate structure formed from sheet metal. The panel may be formed using roll-forming techniques or other known or developed methods for forming sheet metal. 
         [0029]    Panel  20  includes two upstanding vertical leg portions  22 A,B, and an intermediate portion  29 . The vertical leg portions  22 A,B are located on opposing lateral edges of the panel  20  and are mirror images of one another. The vertical leg portions  22 A,B include spreader flanges  23 A,B, inward opening hem sections  24 A,B and vertical sections  26 A,B. The spreader flanges  23 A,B are substantially planar and extend from the lateral edges of the panel  20 . They are oriented on an incline downwardly toward the intermediate portion  29 . As will be discussed in greater detail later, the incline configuration of the spreader flanges  23 A,B facilitate installation of the batten cap  40 . 
         [0030]    The spreader flanges  23 A,B lead to the hem sections  24 A,B. The hem sections  24 A,B create grooves  25 A,B, which open toward the intermediate portion  29  of the panel  20 . The hem sections  24 A,B lead to the vertical sections  26 A,B, which are generally planar sections. 
         [0031]    Extending from the vertical sections  26 A,B are the upturned hem sections  28 A,B. These hem sections  28 A,B are formed into a U-shape positioned on the opposite side of the vertical sections  26 A,B from the intermediate portion  29  (i.e. outboard sides). The hem sections  28 A,B extend to the intermediate portion  29 . In various embodiments, the intermediate portion  29  is formed with a generally convex shape to minimize the appearance of “oil canning.” In other embodiments, the intermediate portion  29  may be substantially planar. 
         [0032]    Turning to  FIG. 3 , the anchor bar  30  is a substantially elongate structure formed from sheet metal or other materials that are sufficiently strong. The sheet metal may be formed using roll-forming techniques, stamping or other known or developed metal forming methods. The anchor bar  30  includes a first U-shaped section  32 , a center section  34  and a second U-shaped section  36 . The first U-shaped section  32  extends from a lateral edge of the anchor bar  30  and opens substantially downwardly to form pocket  33 . The first U-shaped section  32  transitions into the substantially planar center section  34 . The center section  34  defines a plurality of holes (not shown) that are configured to accept fasteners for securing the anchor bar  30  to a structure. Extending from the center section  34  is the second U-shaped section  36 , which is also oriented to open substantially downwardly to form pocket  37 . The anchor bar  30  is secured to the structure  5  using a plurality of fasteners  38  as shown in  FIG. 1 . 
         [0033]    Returning to  FIG. 1 , the batten cap  40  is a generally elongate structure having a U-shaped cross section. The batten cap  40  also includes two inwardly directed locking flanges  42 A,B located on the lateral edges of the batten cap  40 , which are configured to engage the hem sections  24 A,B on adjacent panels  20 A,B. 
         [0034]    Referring to  FIGS. 1-3 , in use, elongate panels  20 A,B are oriented substantially parallel and placed adjacent to each other. An anchor bar  30  is positioned between the adjacent panels  20 A,B such that the U-shaped sections  32 , 36  of the anchor bar  30  engage respective upturned hem sections  28 A,B of the adjacent panels  20 A,B. The anchor bar  30  is then secured to the structure  5  using fasteners  38 . The anchor bars  30  are spaced apart such that the convex shape of the intermediate portion  29  of the panels is maintained and lateral movement of the panels are restricted by engagement anchor bar  30  with the upturned hem sections  28 A,B. The lateral movement restriction can also reduce the chance that static loads such as snow or ice accumulation will flatten the convex shape. 
         [0035]    A batten cap  40  is placed over the vertical legs  22 A,B of the adjacent panels  20 A,B such that the locking flanges  42 A,B engage the spreader flanges  23 A,B of the two vertical legs  22 A,B. As a downward force is applied to the batten cap  40 , the inclined configuration of the spreader flanges  23 A,B causes the vertical legs  22 A,B and/or the legs of the batten cap  40  to flex until the locking flanges  42 A,B engage the grooves  25 A,B. The interaction between the batten cap  40  and grooves  25 A,B resists the passage of water from outside batten seam roofing system  10  to the channel formed by batten system. 
         [0036]    As will be understood by those of skill in the art, the batten seam roofing system will include a plurality of elongate panels oriented substantially parallel with adjacent edges of the panels joined by respective anchor bars and batten caps to form a continuous covering for a subroof. Moreover, the seam created between the batten cap  40  and the adjacent panels  20 A,B is located above the drainage plane of the system, which would lie along the intermediate portion  29 . 
         [0037]    A benefit of various embodiments of the batten systems is that architects can alter the aesthetics of a structure for minimal costs by simply changing the battens used. Profile, style and appearance can be changed while maintaining novel interlock of the batten cap to panel. The largest cost in metal roofing is to produce the panel. However, batten caps are small, shallow, and relatively inexpensive components. 
         [0038]      FIG. 4  illustrates another embodiment of the batten seam roofing system  45  in accordance with the present invention. In this embodiment, the vertical legs do not include open hem sections configured to accept the locking flange of a batten cap. Instead, pockets  48 A,B are formed between the lower end of the vertical legs and the intermediate portions of the panels. These pockets are configured to accept the locking flanges of the batten cap. Since the panel and batten connection is at the drainage plane of the system, moisture may be drawn up between panel and batten legs due to capillary action. To resolve this potential moisture issue, the spreader flanges of the panel legs, when assembled, create a trough or gutter  49 A,B to interrupt the capillary action and to carry moisture away. These gutters  49 A,B act as additional barriers against moisture entering the structure. 
         [0039]    Roofing panels today are typically formed at the job site. It is customary to cut one length of panel for each planar surface and use flashings, counter-flashings, neoprene and metal closures with sealant and fasteners at each change in direction. These joints and laps create a potential for moisture penetration and require highly-intensive skilled manual labor to properly seal, which can be very costly. 
         [0040]      FIGS. 5A-D , illustrate embodiments of the present invention that provide improved systems for accomplishing a change in direction that minimizes labor and the chance of leaks. FIGS.  5 A,B are side views of a panel  20  that illustrate the steps for modifying the panel  20  to accomplish a change of direction, for example a change in the pitch of a roof. As illustrated in  FIG. 5A , a slit may be cut into the vertical legs of the panel  20  thereby creating a hinge  21 . The panel  20  may then be bent about hinge  21  to accommodate the changing direction as shown in  FIG. 5B . 
         [0041]    Similarly, FIG.  5 C,D are side views of a batten  40  that has been modified to accomplish a change in direction. As illustrated in  FIG. 5C , a slit may be cut in the batten  40  to create a hinge  43 . The slit would be at an angle bisecting the change in direction angle. The batten may then be folded about hinge  43  to accommodate the change in direction as illustrated in  FIG. 5D . 
       Standing Seam Embodiments 
       [0042]      FIG. 6  is a schematic diagram of a portion of a standing seam roofing system  50  with a cut-away section illustrating how adjacent panels are secured to a structure  5  in accordance with an embodiment of the present invention. The illustrated embodiment includes two elongate panels  55 A,B, an anchor bar  90 , and fasteners  57 . 
         [0043]      FIG. 7  illustrates a cross-section of a roofing panel  55  for use with a standing seam roofing system  50  of the present invention. The roofing panel  55  includes a first vertical leg  60 , an intermediate portion  70  and a second vertical leg  80 . 
         [0044]    The first vertical leg  60  is located on a lateral edge of the panel  55  and includes a spreader flange  62 , an inward opening hem section  64 , a vertical section  66  and upturned hem section  68 . The spreader flange  62  is substantially planar and extends from a lateral edge of the panel  55  downwardly and toward the intermediate portion  70  at an incline. 
         [0045]    The spreader flange  62  extends to the hem section  64 . The hem section  64  opens toward the intermediate portion  70  of the panel  55  and creates a groove  65 . The hem section  64  leads to the vertical section  66 . 
         [0046]    Extending from the vertical section  66  is the upturned hem section  68 . This hem section  68  is formed into a U-shape located on the opposite side of the vertical section  66  from the intermediate portion  70  (i.e. outboard side) and leads to the intermediate portion  70  of the panel  55 . 
         [0047]    The intermediate portion  70  includes a first ridge  72 , a convex portion  74  and a second ridge  78 . The hem section  68  extends to the first ridge  72 , which is located proximate the vertical section  66  but on the opposite side from the upturned hem section  68 . When installed, the first ridge  72  is spaced apart from the structure. The first ridge  72  transitions downward into the convex portion  74  such that the base  75  of the convex portion  74  is proximate the structure when installed. The convex portion  74  extends from the base  75  to an apex  76 , which is located at the approximate midpoint between the first and second vertical legs  60 ,  80  and then to the base  77  proximate the second vertical leg  80 . When installed, the base  77  is proximate the structure  5 . As discussed earlier with respect to other embodiments, a benefit of the convex shape of the intermediate portion  70  is that it minimizes the appearance of “oil canning” and other visual defects. However, in the illustrated embodiment, the benefits of the standing seam arrangement could still be enjoyed with a generally flat intermediate portion  70 . 
         [0048]    The convex section  74  at the base  77  transitions upward to the second ridge  78 . When installed, the second ridge portion  78  is spaced apart from the structure and is configured to provide clearance for and to conceal the anchor bar  90 . 
         [0049]    The second ridge  78  extends to a downwardly directed hem section  82 , which leads to a vertical leg  83 . The vertical leg  83  is formed over and down to create a general U-shape section  86 . In other embodiments, the vertical leg  83  may be formed over and downward to created different profiles having rounded or squared forms. The terminating edge of the U-shaped section  86  is formed inward to create a locking flange  88 . 
         [0050]      FIG. 8  is a cross-section view of an anchor bar  90  for use with the standing seam roofing system  50 . The anchor bar  90  is an elongate structure made of metal and formed using roll-forming techniques or other known or developed forming methods, or could be formed using other materials or methods provided the resultant bar has sufficient strength properties. The anchor bar  90  includes a base portion  92 , a hemmed attachment portion  94 , vertical leg  96 , a flange  97  and a U-shaped portion  98 . The base portion  92  is substantially planar and is configured to engage a structure on one side. On one lateral side of the base  92 , a hemmed attachment portion  94  is formed. The attachment portion  94  defines a plurality of holes (not shown), which are configured to receive fasteners to secure the anchor bar  90  to a structure. The hemmed attachment portion  94  leads to a vertical leg  96 , which terminates in a substantially horizontal flange  97 . 
         [0051]    The opposite lateral side of the base  92  leads to a substantially U-shaped portion  98 . The U-shaped portion  98  is spaced apart from the vertical leg  96  such that an upwardly directed pocket  99  is created. The U-shaped portion  98 , itself, creates a downwardly directed pocket. 
         [0052]    Referring to  FIGS. 6 ,  7  and  8 , the method of assembly of the standing seam roofing system  50  will be described. First, a panel  55 B is positioned on a structure  5 . The U-shaped portion  98  of the anchor bar  90  is laid over the upturned hem section  68  of the first vertical leg  60  of the panel  55 B. Next, the anchor bar  90  is secured to the structure using fasteners  57 . Alternatively, the anchor bar  90  could be secured first to the structure  5  and then the upturned hem section  68  is turned under the U-shaped portion  98  of the anchor bar  90 . Although only one length of anchor bar  90  is illustrated, multiple lengths could be aligned and even spaced along a common axis on the structure  5  to achieve the necessary anchoring. 
         [0053]    After securing the first panel  55 B using the anchor bar  90 , a second panel  55 A is positioned adjacent the first panel such that second vertical leg  80  of the second panel  55 A is positioned above the first vertical leg of the  60  of the first panel  55 B. The spreader flange  62  of the first panel  55 B is positioned inside the U-shaped section  86  of the second panel  55 A. By applying a downward force on the second vertical leg  80  of the second panel  50 A, the inclined configuration of the spreader flange causes one or both of the vertical legs  60 ,  80  to flex as the second vertical leg  80  of the second panel  55 A moves downward until the locking flange  88  of the second panel  55 A engages the pocket  65  of the first panel. Simultaneously, the hem section  82  of the second panel  55 A engages the pocket  99  of the anchor bar  90 . 
         [0054]    The engagement of the hem section  82  by the pocket  99  of the anchor bar  90  discourages “rib spread,” which is often experienced by prior art designs when subjected to an uplift wind load. In prior art designs, an uplift wind load often causes a ballooning effect that spreads the base of the ribs causing excessive stress on the seam along the ribs created by joining the vertical legs of the adjacent panels. The engagement by hem section  82  of the pocket  99  as well as the engagement of the hem section  68  with the anchor bar  90  significantly reduce the stress on the seam between the adjacent panels and improves uplift wind load resistance of the panel system. 
         [0055]      FIG. 9  illustrates another embodiment of the standing seam roofing system  100 . In this embodiment, the “standing seam” has a tubular profile, while the prior standing seam embodiment  50  had a U-shaped profile. The standing seam roofing system  100  includes two elongate panels  105 A,B and an anchor bar  90 . The various hemmed sections and the anchor bar, which facilitate attachment of the roofing system to a structure are the same as the prior standing seam embodiment  50 . The differences lie in the profile of the “vertical legs” as is discussed below. 
         [0056]      FIG. 10  is a cross-section view of a panel  105  for use in the standing seam roofing system  100 . The roofing panel  105  includes a first vertical leg  110 , an intermediate portion  130  and a second vertical leg  140 . The first vertical leg  110  is directed upwardly and located on a lateral edge of the panel  105 . 
         [0057]    The first vertical leg portion  110  includes a spreader flange  112 , an inwardly opening hem section  114 , an arcuate portion  116 , a vertical portion  118  and an upturned hem section  120 . The spreader flange  112  extends from the lateral edge of the panel  105  downwardly at an incline toward the intermediate portion  130  and terminates in the inwardly opening (i.e. toward the intermediate portion) hem section  114 . The hem section  114  creates a pocket  115 . 
         [0058]    The hem section  114  leads to an arcuate section  116 , which extends approximately 90 degrees. This arcuate section  116  terminates in a vertical leg  118 , which extends at an angle inwardly and downwardly. The vertical leg  118  extends to an upturned hem section  120 , which is formed into a U-shape located on the outboard side of the panel. The hem section  120  transitions into the intermediate portion  130 . The intermediate portion  130  includes a first ridge portion  132 , a convex portion  134  and a second ridge portion  136 . The various portions of the intermediate portion  130  are configured similar to that described with reference to the previous embodiment intermediate portion  70 . 
         [0059]    The second ridge portion  136  extends to a downwardly directed hem section  142  of the second vertical leg  140 . The hem section  142  leads to a substantially planar vertical section  144 , which itself terminates at an arcuate section  146 . The vertical section  144  is angled outwardly as it extends to the accurate section  146 . In the illustrated embodiment, the arcuate section  146  extends to approximately 270 degrees. The arcuate section  146  terminates in a locking flange  148 . The locking flange is configured to engage the pocket  115  of a first leg of an adjacent panel such that the combination of the arcuate section of the first leg and the arcuate section of the section leg generally form a circle as shown in  FIG. 9 . 
         [0060]    Referring to  FIGS. 6 ,  9  and  10 , the method of assembly of the standing seam roofing system  100  will be described. Initially, a first panel  105 B is laid into position. The U-shaped portion  98  of the anchor bar  90  is laid over the upturned hem section  120  of the first vertical leg  110  of panel  105 B. Next, the anchor bar  90  is secured to the structure using fasteners. As with the prior embodiment  50 , these steps may be reversed and multiple anchor bars  90  may be used. 
         [0061]    After securing the first vertical leg of panel  105 B using the anchor bar  90 , a second panel  105 A is positioned adjacent the first panel  105 B such that second vertical leg  140  of the second panel  105 A is positioned above the first vertical leg  110  of the first panel  105 B. The spreader flange  112  of the first panel  105 B is positioned inside the arcuate section  146  of the second panel  105 A. By applying a downward force on the second vertical leg  140  of the second panel  105 A, the inclined configuration of the spreader flange  112  causes one or both of the vertical legs  110 ,  140  to flex as the second vertical leg  140  of the second panel  105 A moves downward until the locking flange  88  of the second panel  105 A engages the pocket  115  of the first panel  105 B. Simultaneously, the hem section  82  of the second panel  105 A engages the pocket  99  of the anchor bar  90 . 
         [0062]    One advantage the various embodiments of the present invention have over the prior art is that movement of the panels proximate the vertical legs is minimized due to the engagement of the anchor bar and hemmed sections of the adjacent panels. In particular, the engagement of the hem section  82  by the pocket  99  of the anchor bar  90  as well as the engagement of the upturned hem section  68  by the anchor bar  90  discourages rib spread. By restricting movement of the panels, uplift wind performance is improved. In prior art designs, the seam was relied on to restrict movement of the panels and when the panels experienced an uplift wind load, the panels would tend to spread or separate proximate the seam (e.g., rib spread condition). In various embodiments of the present invention, the anchor bar maintains the seam configuration by securing both panels proximate the seam. In addition, by placing the securing responsibility on the anchor bar instead of the seam in various embodiments of invention, a substantial stress is removed from the seam. This can improve seam durability. 
         [0063]    The convex surface between the vertical legs of the various embodiments provide many benefits over the prior art. For example, the convex surface minimizes “oil canning.” Also, the convex surface accommodates thermal movement of the panels. In particular, during the heat of the day, thermal movement may cause the convex area to rise slightly. Similarly, curvature of the convex section may decrease slightly during cold days. Furthermore, since the convex surface is raised slightly thereby created a void between the panel and the sub-roof, projections and fasteners will have decreased affect on the visual appearance of the panels. Thus, embodiments of the present invention may decrease the effect of these projections on the aesthetics of the finished roof or wall. 
         [0064]    Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Summary:
Embodiments of the present invention provide improved metal roofing and siding systems. In one aspect of the invention, a roofing or siding system configured to be positioned against a structure is provided. The roofing or siding system includes a first panel including a female locking element opening away from the structure when positioned thereon; a second panel including a male locking element directed toward the structure when positioned thereon; and an anchor bar configured to be attached to the structure, wherein the anchor bar defines an channel directed away from the structure which is configured to engage the male locking element and defines a flange directed towards the structure that is configured to engage the female locking element.