Patent Publication Number: US-11639604-B1

Title: Triangular standing seam metal roof panel and cover system

Description:
FIELD OF THE INVENTION 
     The present invention relates to metal panels and metal panel cover systems, and more particularly, to “triangular” standing seam metal roof panels and roof cover systems using the triangular standing seam metal roof panels. 
     BACKGROUND OF THE INVENTION 
     There are a wide variety of metal covers that have been used in the construction industry to provide a building&#39;s outermost barrier to wind and water. They may be manufactured to resemble wood shake, slate, shingles, clay tiles or other non-metallic cover materials and may be installed on exterior walls or on roofs. More typically, however, metal roof covers utilize rather elongated metal panels installed along the slope of a roof. 
     Metal panel roofs utilize various flashings and other components where the fields of a roof terminate or intersect, such as the eaves, gables, valleys, ridges, and hips of a roof. Even in roofs having many different intersecting or overlapping fields, however, the basic construction of metal panel roofs across the expanse of a roof is fairly standard. Most commonly, an array of spaced, elongated support members or “purlins” is mounted across the structural rafters of a roof substructure. The purlins run horizontally across the rafters, i.e., across the slope of the roof. Layers of insulation and various barriers may be, and for climate-controlled buildings usually are installed as well. Decking also may be provided instead of or in addition to purlins for additional support. A cover is provided by a series of rather elongated, mostly flat, interconnected metal panels. 
     Each cover panel is typically about a foot to three feet in width. Though they may be cut to any length, they commonly are 30 to 40 feet long and may run as long as 200 feet. Preferably, they run the length of the slope over which they are installed. The lateral edges of the panels are bent in various configurations to form upwardly extending sides and a trough in the middle. The trough is where most of the water will be shed from the roof. Adjacent panels are joined along their upwardly extending sides to create relatively narrow seams which are elevated above the trough. 
     The panels are laid out such that the seams run vertically, i.e., with the slope of the roof. The panels also may have one or more vertical ridges running through the trough, and it is those vertical seams and ridges that create the distinctive appearance that consumers associate with metal roofs. More importantly, however, since the seams between adjacent panels are formed a few inches above the troughs where most rain will be shed, metal panel roofs can be very resistant to leaking. 
     Raised-seam, metal panels may be classified according to the way they are installed. So called “through panel” or “exposed” fastener panels are installed with screws or other fasteners that penetrate through the cover panels. The panels typically are laid over a roof so that their sides overlap and form a raised, often trapezoidal shaped seam or “lap” rib. The panels then are joined together along the lap rib by, e.g., gasketed screws. Gasketed screws also are driven through the trough. Leakage around the fastener, at least initially, is not a significant problem. Over time, however, the elastomeric material from which the screw gaskets are fabricated can deteriorate, and leaks tend to develop around penetrating fasteners. 
     “Standing seam” covers can provide better resistance to leakage over longer periods of time and, in the eyes of many beholders, provide a more beautiful roof. In a standing seam cover, the metal panels are secured with concealed connectors or “clips” instead of unsightly and leak-prone penetrating fasteners. Most commonly, a plurality of relatively small panel clips is installed in a fairly widely spaced, array running vertically in what will become a seam line between adjacent panels. Panels then are installed between the vertical lines of clips, with the upturned seam edges of the panels abutting and mating with the clips and each other. There are no penetrations through the panels when clips are used. Moreover, all gaps between the panels and the clips are elevated well above the trough through which most water runoff occurs. Thus, standing seam panel covers provide better, longer resistance to leakage as compared to covers using screws or other “exposed” fasteners that penetrate the panels. 
     Providing adequate uplift resistance, however, can be a greater challenge in standing seam panel covers. That is, most damage to roof covers is caused by wind blowing over the surface of the roof. That air flow forms low pressure areas over the roof and creates an uplift force in much the same way that the wing of an aircraft creates lift forces. While such forces are essential for flight, the uplift forces created by powerful winds over a roof can peel metal panels or other roof coverings away from the roof. It is relatively easy to provide a sufficient number of fasteners in exposed fastener covers. Since they are connected only along their seam lines, however, providing a sufficiently secure connection for panels in a standing seam cover is more problematic. 
     In addition, not all parts of a roof experience the same uplift forces in a given wind. The exposed edges of a roof experience greater uplift forces, and a given surface or field of a roof may be divided into three zones in recognition of such differences. The “edge” zones include those areas within a certain distance, usually around 8 feet, of an eave or gable. If the pitch of a roof is greater than 2 inches per foot of slope, the areas adjacent the ridge and hip of the roof also are considered “edge” zones. The edge zones experience greater wind uplift pressures than most of the roof and typically constitute approximately 15% of a roof&#39;s surface. The greatest uplift pressures, however, are in the “corner” zones. Those are the areas where edge zones overlap, and they typically constitute approximately 5% of the surface of a roof. The “field” zone is the rest of the roof field, and it constitutes approximately 80% of the roof surface. The field zone experiences the lowest wind uplift pressures. In any event, providing sufficient resistance to wind uplift has been an increasingly important consideration in roof design as property owners and insurers seek to minimize their potential losses from wind damage, especially in hurricane prone areas like the Gulf and lower Atlantic coast. 
     There are many conventional systems that use non-penetrating clips with standing seam metal panels. In new installations, the clips often are mounted to an array of spaced, elongated support members or “purlins” which are mounted across the structural rafters of a roof substructure. The purlins run horizontally across the rafters, i.e., across the slope of the roof. In other roofs, the clips may be mounted to decking installed on the roof substructure. 
     Such systems are disclosed in U.S. Pat. No. 4,575,983 to H. Lott, Jr. el al. Panel clips are mounted to purlins, and the metal panels secured to the clips. The panels disclosed therein are asymmetrical standing seam panels. Asymmetrical panels have mating male-female connections, each panel having a male connection formed in one side and a female connection formed in its other side. Thus, installation must proceed in a certain direction across the roof, and removal for repair must proceed in the opposite direction. 
     Symmetrical standing seam panels, however, have sides that are mirror images of each other and are joined with a separate seam cover. Symmetrical panels, therefore, may be installed in either direction. A damaged panel also may be removed for replacement without removing any adjacent panels. Examples of symmetrical standing seam roof covers where non-penetrating individual clips are mounted to purlins are disclosed in U.S. Pat. No. 4,649,684 to L. Petree et al. Other covers, such as those disclosed in U.S. Pat. No. 6,354,045 to M Boone et al. and U.S. Pat. No. 5,737,892 to P. Greenberg, utilize individual and elongated, “continuous” clips that are mounted to and span adjacent purlins. While they may be more expensive than covers using asymmetrical panels, such symmetrical panel covers can offer improved leak protection, better uplift resistance, and longer service life. 
     Metal roof panels most commonly are fabricated from relatively thin metal coiled sheets. A coiled metal sheet is run through a roll former to provide the lateral edges of the panel with the geometry or “profile” required for forming seams between panels. Any desired vertical or horizontal ridges running through the trough are formed along with the shaping of the lateral edges. Necessarily, then, the resulting panel is thin and very flexible. 
     Seams between adjacent panels and ridges in the trough provide some resistance to flexing. When a cover is installed on an array of purlins, however, the panels will extend across the spacing between the purlins, typically from about 2.5 to about 5 feet. Many conventional panels will flex under load, for example, load created when a person walks across the panel. Load may be supported, but flexing of the panel creates a feeling of insecurity in persons traversing the cover. Flexing also can damage the seams. Even if the seams are not damaged, flexing over time can lead to “telegraphing” of the purlins. That is, subtle bending of the panels where they cross over purlins becomes visible and detracts from the aesthetics of the cover. Such issues are exacerbated as the roof becomes flatter. 
     Flexing may be reduced or essentially eliminated by installing the cover over a deck. Indeed, for architectural roof panels, a deck is typically required. Architectural metal panels are generally installed over relatively steep roofs, those having a minimum slope of about 3 inches per foot of slope. The roof surfaces being more visible, aesthetics may be more valued. The panel seams in architectural metal panel roofs are hydrokinetic, i.e., water shedding, and are relatively short, usually 0.5 to 1.5 inches high. The profile of architectural panels also typically is less complicated and dramatic. Thus, the panels may be formed more easily. Installing the required supporting deck, however, adds significantly to the cost of the roof cover. Adding more purlins and decreasing their spacing may be an option, but that too adds significant cost. 
     Thus, structural metal panels are most commonly used over flat and relatively low slope roofs, recognizing that even “flat” roofs preferably have a minimum of 0.25 inch per foot of slope to provide runoff. A structural panel roof cover is designed to support weight without a deck. They may be installed on an array of relatively widely spaced purlins. The panels, therefore, have a more complicated, dramatic profile. The seams are significantly higher than in architectural panels, usually about 3 inches high. A greater number of bends also typically is required to provide the panel with a more load-resistant profile. Since ponding water is a potential issue in flat and low-slope roofs, especially over time as settling of the structure may occur, the seams of a structural cover also are hydrostatic, that is, water-tight. 
     So-called trapezoidal standing seam panels are common examples of structural metal roof panels that provide significant resistance to flexing. Panels of this type are available commercially from a number of manufacturers, such as the Masterlock FS mechanically-seamed panels sold by McElroy Metal Mill, Inc., Bossier City, La. Other types of trapezoidal, standing seam metal panels are available as well, including so-called “snap-in” panels, such as the Masterlock standing seam panels produced by McElroy Metal, and “hook and roll in place” panels such as those disclosed in U.S. Pat. Nos. 5,692,352, 5,737,894, and 6,301,853 to H. Simpson et al. and the TS-324 metal panel system licensed by Building Research Systems, Inc. to Schulte Building Systems and other manufacturers. 
     An exemplary conventional trapezoidal standing seam metal panel  120  is shown in  FIGS.  1  and  2   . As may be seen in  FIG.  1   , panel  120  is generally elongated and has sides  123  that define a trough  122  running longitudinally through panel  120 . Smaller vertical ridges  126  run longitudinally through trough  122 . Sides  123  are formed by various bends in the lateral edges of panel  120  as seen best in  FIG.  2   . Panel  120  is bent upward from trough  122  first at a relatively shallow angle and then at a relatively steep angle. The two angled portions lead into a horizontal extension running generally parallel to the trough. Additional bends are formed beyond the horizontal extension. Those bends provide the portions that overlap and are formed into standing seams  121  between adjacent panels as shown in  FIG.  2   . Standing seams  121  are formed and supported on clips  130  that are mounted on purlins  61 . When adjacent panels are seamed, a relatively wide, vertical beam  124  is created. Along with standing seams  121  and vertical ridges  126 , vertical beams  124  provides panels  120  with substantial resistance to flexing. 
     The geometry that provides its resistance to flex, however, imposes significant limitations on the fabrication of trapezoidal standing seam panels. Their profile is more complex and more dramatic than that of other, albeit more flexible standing seam panels such as architectural panels. Architectural panels may be fabricated with smaller roll formers that may be transported to a job site. Since it is formed on site, the panel may be fabricated in much longer lengths, up to 200 feet or more. That will allow the panels in most cases to extend the entire length of the slope over which they are installed. Potentially problematic end laps in a run are usually avoided. 
     Creating the more complex and dramatic profiles in conventional trapezoidal standing seam panels, however, is more difficult. More, and more pronounced bends must be formed in the panel. As a practical matter, trapezoidal standing seam metal panels must be formed by heavy, more complex and capable, fixed-base roll formers. Such roll formers are extremely difficult to transport, and rarely, if ever, are moved from job site to job site. Given the number of bends, it also a more difficult to maintain consistent fabrication of panels to specification. 
     Consequently, virtually all conventional trapezoidal standing seam metal panels are fabricated in the factory and are cut to a transportable length, typically from about 40 to about 50 feet. Panels of those lengths, however, do not always cover the entire slope. It may be necessary to use several panels for a run, and end laps may have to be provided between the panels. Such end laps are potential sources of leaking and are more susceptible to wind uplift. 
     Moreover, even when produced to specification, it is more difficult to install conventional trapezoidal standing seam panels with proper modularity. That is, during installation, the specified width of the panels must be maintained as they are seamed along their lateral edges. Many conventional trapezoidal standing seams, however, because of their profile and the bends therein, tend to expand and contract laterally—in an accordion-like fashion—as they are installed. That makes it more difficult to install panels to specification, that is, to maintain modularity through the cover. The width of a panels may end up being different at one end than at the other, or in the mid-section of the panel. The width of the sidelap also can deviate significantly off specification. Such variation, or lack of modularity can detract significantly from the appearance of the cover. It also can create problems in finishing the cover along eaves, ridges, gables, and the like. 
     The statements in this section are intended to provide background information related to the invention disclosed and claimed herein. Such information may or may not constitute prior art. It will be appreciated from the foregoing, however, that there remains a need for new and improved standing seam metal roof panels and metal panel cover systems. Such disadvantages and others inherent in the prior art are addressed by various aspects and embodiments of the subject invention. 
     SUMMARY OF THE INVENTION 
     The subject invention, in its various aspects and embodiments, is directed generally to standing seam metal roof panels and to metal panel roof covers. One aspect and embodiment of the invention provides for a standing seam metal panel for a roof cover system. The metal panel comprises upstanding symmetrical sides. The sides define lateral edges. A trough extends between the lateral edges. Each lateral edge comprises an angled portion, a vertical portion, and first and second horizontal portions. The angled portion extends upward and outward from the trough. The vertical portion extends upward from the angled portion and generally perpendicular to the trough. The first horizontal portion extends inward from the vertical portion and generally parallel to the trough. The second horizontal portion extends above, outward from, and generally parallel to the first horizontal portion. The lateral edges are formed by bends in the metal panel, the bends thus defining the portions of the lateral edges. The lateral edges are adapted to form a sidelap with the lateral edge of an adjacent the metal panel in the cover system. The sidelap is formed on panel clips of the cover system. 
     Other aspects provide such panels where the lateral edge angled portion of the panel extends from the trough at an angle of from about 30 to about 60°, or at an angle of from about 40 to 50°, or at an angle of about 45°. 
     Still other aspects provide such panels where the first and second lateral edge horizontal portions are doubled over to form a U-shaped channel that is adapted to receive a support portion of the panel clips of the cover system. 
     Further aspects provide such panels where the metal panel comprises a ridge running longitudinally through the trough or where the metal panel comprises two or more such ridges. 
     In other aspects and embodiments, the invention provides for a cover system. The cover system comprises a plurality of panel clips and a metal panel cover attached to the panel clips. The panel clips are attached to a support and arranged in linear arrays running along the pitch of the cover system. The metal panel cover comprises a plurality of the novel metal panels that are interconnected along adjacent lateral edges by sidelaps formed on the panel clips. The sidelaps extending along the pitch of the cover system. 
     Other aspects provide such cover systems where the cover system comprises an array of spaced purlins providing the support. The purlins run across the pitch of the cover system and the plurality of panel clips are attached to the purlins. 
     Still other aspects provide such cover systems where the cover system comprises fibrous batts or other insulation disposed between the support and the metal panel cover. 
     Yet other aspects provide such cover systems where the panel clips are individual panel clips, where the panel clips are continuous panel clips, where the panel clips include individual panel clips installed in a field zone of the cover system and continuous panel clips installed in an edge zone of the cover system, or where the panel clips include individual panel clips installed in a field zone of the cover system and continuous panel clips installed in a corner zone of the cover system. 
     In other aspects and embodiments, the invention provides for a metal panel standing seam roof recover system installed over an existing cover of a roof cover system. The recover system comprises a plurality of panel clips and a metal panel recover attached to the panel clips. The panel clips are attached to the existing cover system and arranged in linear arrays running along the pitch of the roof recover system. The metal panel recover comprises a plurality of the novel metal panels that are interconnected along adjacent lateral edges by sidelaps formed on the panel clips. The sidelaps extend along the pitch of the recover system. 
     Other aspects provide such recover systems where the recover system comprises rigid foam insulation boards or other insulation disposed between the existing cover system and the metal panel cover. 
     Still other aspects provide such recover systems where the existing cover system is a metal panel cover system or a shingled cover system. 
     Yet other aspects provide such recover systems where the existing cover system comprises a support frame having an array of spaced purlins running across the pitch of the existing cover system and the plurality of panel clips are attached to the purlins. 
     Further aspects provide such recover systems where the panel clips are individual panel clips, where the panel clips are continuous panel clips, where the panel clips include individual panel clips installed in a field zone of the existing cover system and continuous panel clips installed in an edge zone of the existing cover system, or where the panel clips include individual panel clips installed in a field zone of the existing cover system and continuous panel clips installed in a corner zone of the existing cover system. 
     In other aspects and embodiments, the invention provides methods of installing a standing seam metal panel roof cover system. The method comprises installing a plurality of panel clips and attaching a plurality of the novel panels to the panel clips. The panel clips are installed on an array of spaced purlins running across the pitch of the cover system and in linear arrays running along the pitch of the cover system. The metal panels are attached to the panel clips by forming the sidelaps on the panel clips. 
     Other aspects provide such methods where the panel clips are individual panel clips, where the panel clips are continuous panel clips, where the panel clips include individual panel clips installed in a field zone of the cover system and continuous panel clips installed in an edge zone of the cover system, or where the panel clips include individual panel clips installed in a field zone of the cover system and continuous panel clips installed in a corner zone of the cover system. 
     Finally, still other aspects and embodiments of the invention will provide such panels, cover and recover systems, and methods having various combinations of such features as will be apparent to workers in the art. 
     Thus, the present invention in its various aspects and embodiments comprises a combination of features and characteristics that are directed to overcoming various shortcomings of the prior art. The various features and characteristics described above, as well as other features and characteristics, will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments and by reference to the appended drawings. 
     Since the description and drawings that follow are directed to particular embodiments, however, they shall not be understood as limiting the scope of the invention. They are included to provide a better understanding of the invention and the manner in which it may be practiced. The subject invention encompasses other embodiments consistent with the claims set forth herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    (prior art) is an isometric view of a conventional trapezoidal standing seam metal roof panel  120 . 
         FIG.  2    (prior art) is an enlarged cross-sectional view of a standing seam  121  formed between two conventional metal panels  120  shown in  FIG.  1   , which view is taken generally perpendicular to standing seam  121 . 
         FIG.  3    is a plan view, having partial tear-away views, of a first preferred embodiment  10  of the novel roof covers of the subject invention. 
         FIG.  4    is a perspective, partially exploded view of a portion of novel roof cover  10  taken generally from an area  4  of  FIG.  3   , which portion has been installed across a boundary between edge zone E and corner zone C of roof cover  10  (certain components of novel roof cover  10  having been omitted therefrom). 
         FIG.  5    is a cross-sectional view taken generally perpendicular the vertical planes of standing seams  21  of novel roof cover  10  shown in  FIG.  4   . 
         FIG.  6    is an enlarged, detailed view of portion  5  of the view shown in  FIG.  5   . 
         FIG.  7    is an isometric view of a preferred embodiment  20  of the novel “triangular” standing seam metal roof cover panels of the subject invention, metal panel  20  being used in novel roof cover  10  shown in  FIGS.  3 - 6   . 
         FIG.  8    is a lateral cross-sectional view of novel metal panel  20  shown in  FIG.  7   . 
         FIG.  9    is an isometric view of an individual panel clip  30  used in novel roof cover  10  shown in  FIGS.  3 - 6   . 
         FIG.  10    is an isometric view of a first continuous panel clip  40  used in novel roof cover  10  shown in  FIGS.  3 - 6   . 
         FIG.  11    is an isometric, slightly exploded view of a second continuous panel clip  140  that may be used in novel roof cover  10  shown in  FIGS.  3 - 6   . 
         FIG.  12    is an isometric view of a third continuous panel clip  240  that may be used in novel roof cover  10  shown in  FIGS.  3 - 6   . 
         FIG.  13    is a top view, including partial tear-away views, of a conventional metal panel roof  200  which has been recovered with novel roof cover  10 . 
         FIG.  14    is an isometric, partially exploded view of a portion of novel roof cover  10  installed over existing roof  200  taken generally from an area  14  of  FIG.  13   , which portion has been installed across a boundary between edge zone E and corner zone C of existing roof  200  (certain components of novel roof cover  10  having been omitted therefrom to better show underlying components). 
         FIG.  15    is a cross-sectional view, taken generally perpendicular to standing seams  21  of novel roof cover  10  shown in  FIGS.  13 - 14   . 
         FIG.  16    is an enlarged, detailed view of portion  16  of the view shown in  FIG.  15   . 
     
    
    
     In the drawings and in the description that follows, like parts are identified by the same reference numerals. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional design and construction may not be shown in the interest of clarity and conciseness. 
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     The present invention generally relates to standing seam metal roof panels and to metal panel roof covers. Various preferred embodiments of the novel roof panels have upstanding symmetrical sides defining lateral edges. A trough extends between the lateral edges. The lateral edges, as described further below, have bends that define edge portions. The edge portions provide the lateral edges with a geometry that allows the lateral edges to form a seam or sidelap with the lateral edge of an adjacent panel. Preferred embodiments of the novel roof covers comprise a plurality of the novel metal roof panels that are interconnected along adjacent lateral edges by sidelaps formed on a plurality of fixed panel clips. 
     For example, a first preferred embodiment  10  of the novel metal panel roof covers and components thereof are shown in  FIGS.  3 - 10   . As best appreciated from  FIGS.  4 - 6   , novel roof cover  10  generally comprises a plurality of a first preferred embodiment  20  of the novel metal roof panels, individual clips  30 , continuous clips  40 , and purlins  61 . 
     Novel panel  20 , as seen best in  FIGS.  7 - 8   , has upturned sides  23  that provide lateral edges running along the length of panel  20 . A trough  22  extends between sides  23 . Preferably, ridges are provided in trough  22 , such as ridges  26  that extend lengthwise or vertically through trough  22 . Horizontal ridges also may be provided in trough  22  if desired. Sides  23  are bent to provide them with a geometry that allows them to be joined to form a seam or sidelap  21  between adjacent panels  20  in roof cover  10 , as will be described further below. Sidelaps  21  are elevated above trough  22 , and thus, most of the water falling on roof cover  10  will be shed through troughs  22 . 
     Novel panel  20  is referred to as a symmetrical panel. That is, sides  23  of panel  20  are mirror images of each other. Panels  20  also are standing seam panels. That is, as described further below, sidelaps  21  between adjacent panels are formed on clips  30  and  40  without the use of penetrating fasteners. When panels  20  are joined by sidelaps  21  and viewed in cross-section as in  FIGS.  5 - 6   , sides  23  form what may be viewed as a bisected triangular shape, the base of which is an imaginary line extending along the plane of trough  22 . Thus, and in contradistinction to so-called “trapezoidal,” asymmetrical standing seam metal panels such as prior art panel  120 , novel panels  20  may be referred to as “triangular,” symmetrical, standing seam, metal panels. 
     As shown in  FIGS.  3 - 4   , panels  20  in roof cover  10  are installed on a support frame that comprises an array of spaced, elongated bar joists or purlins  61 . Purlins  61  are mounted on structural rafter beams (not shown) of a roof substructure and run “horizontally” through the roof. That is, purlins  61  are installed and run across the slope of a roof, as opposed to running “vertically” or with the slope. Panels  20  are installed such that they, and sidelaps  21  joining adjacent panels  20  run vertically across purlins  61 . The upper ends of panels  20  extend under a ridge cap  11  provided along a peak line of roof cover  10 . Preferably, each panel  20  runs down the entire slope of roof cover  10  to an eave or valley (not shown). Alternately, panels  20  may be overlapped at their ends. 
     Purlins  61  may be any type of elongated support member, but are exemplified herein as “Z” purlins of the type widely used in metal roofs and building covers. As seen best in  FIG.  4   , purlins  61  have a flange  62  extending generally horizontally in one direction from the lower end of a vertically oriented body  63 . Another flange  64  extends generally horizontally in the other direction from the upper end of body  63 . Lower flange  62  provides a base by which purlins  61  are attached to the rafter beams (not shown). Upper flange  64  provides a surface upon which is mounted roof cover  10 . Lower flange  62  and upper flange  64  also preferably and typically are provided with angled edges to provide greater structural integrity and strength to purlin  61 . 
     Panel clips are used to secure the novel panels to the cover support and to facilitate the formation of standing seams between the panels. Individual clips  30  and continuous clips  40 , for example, are used to secure cover panels  20  to purlins  61  and to facilitate the formation of seams  21  between laterally adjacent panels  20  as shown in  FIGS.  4 - 6   . They are arranged in linear arrays running vertically across purlins  61 . Clips  30  and  40  are attached to purlins  61  by fasteners, such as self-tapping metal screws  13  shown in  FIGS.  5 - 6   . 
     Preferred embodiments of the subject invention include metal panel roof covers in which individual panel clips are installed in the field of the roof cover and continuous clips are installed in corner zones, and where either individual or continuous clips are installed in edge zones of the roof cover. For example, novel roof cover  10  includes large field zones F, edge zones E, and corner zones C as shown in  FIG.  3   . Individual panel clips  30  are installed in field zones F and edge zones E and continuous clips  40  are installed in corner zones C. That may be best appreciated by reference to  FIG.  4   , which is a section  4  of novel roof cover  10  installed across a boundary between an edge zone E and a corner zone C. 
     As exemplified therein, individual clips  30  are mounted on purlins  61  in linear arrays. The arrays of individual clips  30  run vertically through field zones F and edge zones E of roof cover  10  along what will become the seam lines for cover panels  20 . Thus, the linear arrays of clips  30  are separated horizontally by a distance substantially equal to the width of cover panels  20 . 
     Continuous clips  40  are installed in corner zones C of roof cover  10 . Like individual clips  30 , continuous clips  40  are mounted along what will become seam lines for cover panels  20 . Thus, they too are offset from each other by a distance approximately equal to the width of panels  20 . In contrast to individual clips  30 , however, continuous clips  40  are elongated and extend across adjacent purlins  61 . Continuous clips  40 , therefore, provide continuous support for panels  20  through corner zones C, thus providing greater resistance to wind uplift in those areas experiencing the greatest uplift forces. 
     If desired or necessary, increased resistance to wind uplift may be provided in roof edge zones E by providing continuous clips in those zones instead of individual clips as in roof cover  10 . Similarly, in the zones where they are employed, individual clips typically will be installed on every purlin along the seam line as are clips  30  in roof cover  10 . If resistance to wind uplift is not a great concern, however, it may not be necessary to install an individual clip on every purlin. It also will be appreciated that continuous clips preferably extend across the entire corner zones or, if employed therein, the edge zones of a roof. Shorter continuous clips may be employed, however, and arranged in a line across the zone such that their ends overlap, abut, or are spaced somewhat apart with the result that support for recover panels is provided across substantially the entire run through the zone. Similarly, if desired, resistance to wind uplift, as well as rigidity may be maximized by using continuous clips across the entire cover. In any event, by selectively installing either individual or continuous clips across the roof, it is possible to provide a standing seam roof cover with increased resistance to wind uplift in those areas requiring greater resistance, yet which requires fewer parts, may be installed more easily, and has lower material costs. 
     As seen best in  FIG.  9   , individual clips  30  in field zones F and edge zones E include a bottom flange or base  32  and top flanges  34  that extend generally horizontally from a vertically oriented web or body  35 . Individual clips  30  are attached to purlins  61  by fasteners, such as self-tapping, metal screws  13 , extending through bottom flange  32  of clips  30  and top flange  64  of purlins  61 . Preferably, preformed round apertures  36  are provided in base  32  of individual clips  30  to accommodate screws  13  or other fasteners. If desired, however, slots may be provided, or screws may be driven through base  32 . 
     It will be appreciated that a greater or lesser number of screws  13  or other fasteners may be used to mount individual clips  30  to purlins  61 . Typically, at least two fasteners will be used to resist torque about the connections and to provide greater stability for individual clips  30 . Additional screws  13  or other fasteners may be used when more stability and strength is required in the connection between individual clips  30  and purlins  61 . 
     The length of clips  30  and base  32  thereof, as well as the placement, configuration, and number of apertures  36 , preferably are coordinated to allow for some imprecision in placement of clips  30  during installation while ensuring that a sufficient number of fasteners may be driven into purlins  61 . It also is preferable that individual clip  30  and base  32  be sufficiently long so as to allow for a more stable and secure connection to purlins  61 . 
     Top flanges  34  provides support for cover panels  20  and facilitate the formation of standing seams  21  between cover panels  20 . As mentioned previously, the lateral edges of panels  20  are bent upwards to provide upwardly extending sides  23  on both sides of trough  22 . More specifically, and as best appreciated from the cross-sectional views of  FIGS.  5 - 6  and  8   , sides  23  comprise an angled portion  23   a , a vertical portion  23   b , a first horizontal portion  23   c , and a second horizontal portion  23   d , all formed by bends in panel  20  and running the length of panel  20 . Angled portion  23   a  extends upward and outward from trough  22 . Vertical portion  23   b  extends upward from angled portion  23   a  and generally perpendicular to trough  22 . First horizontal portion  23   c  extends inward from vertical portion  23   b  and generally parallel to trough  22 . Second horizontal portion  23   d  extends above, outward from, and generally parallel to first horizontal portion  23   c . First and second horizontal side portions  23   c  and  23   d  are doubled over horizontally to form a narrow U-shaped channel  24  that runs vertically along the top of each side  23  of panels  20 . It will be noted again that sides  23  are mirror images of each other, thus providing panel  20  with a longitudinal plane of symmetry. 
     As recover panels  20  are installed, U-shaped channels  24  in the upper portion of sides  23  of panels  20  are slipped over top flanges  34  of clips  30 . A seam cover  25  then is provided over and around side portions  23   c  and  23   d , that is, the exterior of channel  24  to secure panels  20  to each other and to clips  30 . Preferably, a sealant, such as a bead of silicone caulk or elastomeric tape, is provided between seam cover  25  and the exterior of channels  24  to enhance the weather tightness of seams  21 . A seamer also may, and preferably is used to securely connect and seal seam cover  25  to panel sides  23 . 
     The exact dimensions of top flanges in the individual clips are not especially critical and may be varied somewhat to provide as much or as little support surface as may be desired or necessary for a particular installation. Likewise, clips  30  have three top flanges  34 , two flanges  34  extending in one direction and one flange  34  extending in an opposite direction. Other clips, however, may be provided with any number of top flanges extending in alternating directions. 
     Continuous clips  40 , as seen best in  FIG.  10   , are formed from two similar, nesting components  41   a  and  41   b . More particularly, clip components  41  have a bottom flange  42  and a top flange  44  extending generally horizontally from a vertically oriented web or body  45 . They are substantially identical except that top flange  44  of clip component  41   a  and top flange  44  of clip component  40   b  extend in opposite directions. Body  45  of clip component  41   b  also is slightly shorter than body  45  of clip component  41   a , such that when clip components  41  are nested together, their top flanges  44  will be substantially aligned. 
     Continuous clips  40  are attached to purlins  61  in a manner similar to individual clips  30 . Fasteners, such as self-tapping, metal screws, may be driven through bottom flanges  42  of clips  40  and top flange  64  of purlins  61 . As with individual clips  30 , a greater or fewer number of fasteners may be used as required to provide the necessary strength of connection. Continuous clips  40 , because of their extended length, typically will be fabricated from lighter gauge metal, and thus, self-tapping metal screws typically can be driven easily through them during installation. If desired, however, prefabricated apertures, slots, and the like may be provided therein to accommodate screws or other fasteners. 
     The length of clip components  41  is coordinated such that clips  40  span at least the distance between adjacent purlins  61 , but preferably such that clips  40  extend across all purlins  61  in the corner zone of roof cover  10 . The width of base  42 , as well as the placement, configuration, and number of any apertures present, preferably are coordinated to allow for some imprecision in placement of clip components  41  during installation while ensuring that a sufficient number of fasteners may be driven into purlins  61 . 
     Top flanges  44  of continuous clips  40 , similar to top flanges  34  in individual clips  30 , engage adjacent panels  20  and assist in the formation of standing seams  21  therebetween. More particularly, top flanges  44  are configured such that sides  23  of panels  20  may be engaged therewith by slipping U-shaped channels  24  around top flanges  44 . Seam cover  25  then is placed over and around channels  24  to secure panels  20  to each other and to continuous clips  40 . Sealants and seamers also are preferably used to form a secure, weather tight seam along continuous clips  40 . 
     The clips used in the novel metal panel roof recovers preferably are made from steel, such as 16 to 24-gauge galvanized steel sheets that may be easily formed and bent and cut into a desired configuration by conventional metal forming equipment. Such materials provide a rugged, weather resistant clip that may be manufactured easily and economically. Continuous clips, given their length, may be made from somewhat lighter gage metal if desired to reduce costs and to allow screws to be driven more easily through the clip instead of providing apertures to accommodate fasteners. Other metals, such as extruded aluminum, may be used to fabricate the panel clips, however, as well as rigid, moldable or extrudable plastics. 
     Likewise, while individual clips  30  and continuous clips  40  are used in preferred embodiments of the novel roof recovers, the invention is not limited thereto. Other clip configurations may be used if desired. For example, while individual clips  30  in novel roof recover  10  are a unitary component, other individual clips suitable for use in other embodiments of the subject invention may have a two-piece design, similar to continuous clips  40 . Likewise, continuous clip  40  may be fabricated as a unitary component, analogous to individual clips  30 . The various flanges in the exemplified clips are integral with their associated clip body. If desired, however, the various flanges may be provided as separate components affixed to a clip body, e.g., by welding. Other suitable clip designs are known and may be used in the novel roof covers. 
     For example, continuous clips  140  shown in  FIG.  11    may be used in the novel cover systems. As may be seen therein, continuous clips  140  are formed from two identical components  141   a  and  141   b . Clip components  141  have a generally C-shaped cross-section and are installed in back-to-back fashion such that the overall cross-section of continuous clips  140  is generally I-shaped. More particularly, clip components  141  have a bottom flange  142  and a top flange  144  extending generally horizontally from a vertically oriented web or body  145 . Bottom flange  142  provides a base by which clips  140  may be attached to a roof support, for example, by driving screws into purlins  61 . The screws typically are driven through base  142  to simplify installation of continuous clips  140 . If desired, however, holes, slots or other apertures may be provided in base  142  to accommodate the passage of fasteners. The length of clip components  141 , like continuous clips  40 , is coordinated such that clips  140  span at least the distance between adjacent purlins  61 , but preferably such that clips  140  extend across all purlins  61  in those zones of the roof in which they will be used. The width of base  142 , as well as the placement, configuration, and number of any apertures present, preferably are coordinated to allow for some imprecision in placement of clip components  141  during installation while ensuring that a sufficient number of fasteners may be driven into existing purlins. 
     Top flanges  144  of continuous clips  140 , similar to top flanges  44  in continuous clips  40 , engage adjacent panels  20  and assist in the formation of a standing seam  21  therebetween. More particularly, top flanges  144  are configured such that sides  23  of panels  20  may be engaged therewith by slipping U-shaped channels  24  around top flanges  144 . Seam cover  25  then is placed over and around channels  24  to secure panels  20  to each other and to continuous clips  140 . Sealants and seamers also are preferably used to form a secure, weather tight seam along continuous clips  140 . 
     Continuous clips  240  shown in  FIG.  12    also may be used in the novel cover systems. As shown there, continuous clips  240  are formed from two identical components  241   a  and  241   b . Clip components  241  have a generally C-shaped cross-section and are installed in back-to-back fashion such that the overall cross-section of continuous clips  240  is generally I-shaped. More particularly, clip components  241  have a bottom flange  242  and a top flange  244  extending generally horizontally from a vertically oriented web or body  245 . Bottom flange  242  provides a base by which clips  240  may be attached to a roof support, for example, by driving fasteners into purlins  62 . Fasteners typically are driven through base  242  to simplify installation of continuous clips  240 . If desired, however, holes, slots or other apertures may be provided in base  242  to accommodate the passage of fasteners. 
     Base  242  has an upwardly angled extending portion from which extends a horizontal shelf flange  243 . Shelf flange  243 , along with horizontally extending top flange  244 , provides support for cover panels  20 . Top flanges  244  also facilitate the formation of standing seams  21  between cover panels  20 . As panels  20  are installed, sides  23  of panels  20  will be supported on shelf flanges  243  in adjacent lines of clips  240 . At the same time, U-shaped channels  24  in the upper portion of sides  23  of panels  20  are slipped over top flanges  244 . A seam cover  25  then is provided over and around the exterior of channels  24  to secure cover panels  20  to each other and to clips  240 . Sealants and seamers also are preferably used to form a secure, weather tight seam along continuous clips  240 . 
     Alternately, continuous support for panel seams across adjacent purlins may be provided by providing a panel support member which straddles two individual clips. The panel support member may be attached and secured to individual clips by any means known in the art, such as glue, welding, or fasteners. The panel support member includes a substantially flat upper surface and a bent flange on each edge of the substantially flat upper surface. The substantially flat upper surface of the panel support member is configured to contact and support the cover panel, for example, by engaging U-shaped channels in a manner analogous to that described above. The panel support member essentially connects the individual clips and creates a support structure for the cover panels. 
     Any of the wide variety of insulating materials commonly used in building construction to reduce heat transfer by conduction, radiation, or convection may be used in the novel metal roof covers. Such insulating materials include polyurethane, isocyanate, and other spray foam insulation, cotton, rock and slag wool, fiberglass, and other fibrous bats and blankets, cellulose and other blown-in fibrous insulation, and expanded or extruded closed cell polystyrene (EPS and XPS), polyisocyanate, and other rigid plastic foam insulation. Various barrier sheets, films, coatings, and facing also may be provided to provide additional thermal resistance, to minimize water condensation in the insulation, or to provide fire resistance to the insulation. 
     The choice of insulating materials will depend in large part on the degree of thermal resistance desired, cost considerations, and the supporting structure on which the cover in installed. For example, as exemplified by novel roof cover  10 , when a cover is installed over purlins batts  51  of fiberglass or other fibrous materials commonly will be used. Batts  51  may be laid across the array of purlins  61  and clips  30  and  40  installed over batts  51 . The height of clips  30  and  40  typically will be such that a small clearance, appropriate for the thickness of the batts used, will be provided between the bottom of panels  20  and the top flange  64  of purlins  61 . The use and installation of batts and other insulation, as well as the use of thermally insulating supports, is well known may adapted or modified readily by workers in the art for use in the novel roof covers. 
     It also will be appreciated that the novel standing seam roof covers almost invariably require the use of other components to complete certain portions of a cover installation. For example, if the roof includes a number of different fields, ridge caps will be provided along the peak and hip lines of the cover, and specialized connectors may be required for their installation. Similarly, flashing may be installed in roof cover valleys and around projections through the roof. Facia and soffit components also may be installed along the eaves and gables of the roof. A wide variety of such components and installation methods are known in the art and may be used in the novel roof covers. 
     The novel panels in certain respects are similar to other standing seam roof panels as are conventionally used in metal panel roof covers. Thus, they may be fabricated from materials and by methods as are commonly employed in the art. Typically, such panels are fabricated from roll stock of painted or unpainted coated steel, such as Galvalume™ steel, zinc, copper, or aluminum. The roll stock is fed into a roll former which shapes the metal sheet into the desired configuration and cuts it to a desired length. The materials and fabrication of metal panels is well known in that art, and conventional materials and fabrication equipment may be used to manufacture the novel panels. 
     Novel roof cover  10  has been illustrated as being installed over a frame comprising an array of purlins  61 . It will be appreciated, however, that the novel roof covers may be installed on a variety of support structures. They may be installed over a deck, for example, and some building owners may prefer a deck despite the increased cost. A deck provides additional support for the panels and also facilitates the use of foam insulation boards in the cover. Importantly, however, it is expected that the profile of sides  23  of panels  20  will allow them to be used as structural panels. That is, panels  20  will provide cover  10  with a sufficient degree of load-resistance to allow it to be installed on spaced purlins  61  as exemplified herein, especially when provided with one or more vertical ridges  26 . 
     Sides  23  will be dimensioned accordingly. For example, for a panel having a width of 24 inches, the overall height of sides  23  will be from about 2.5 to about 3 inches, of which vertical portion  23   b  preferably is the major portion. Horizontal portions  23   c  and  23   d  will extend horizontally from about 0.5 to about 0.75, preferably about 0.625 inches. As exemplified, horizontal portion  23   d  may be somewhat shorter than horizontal portion  23   c  as that may help with inserting the top flanges of clips into the U-shaped channel  24 . Angled portion  23   a  will extend at an angle of from about 30° to about 60°, more preferably from about 40° to about 50°, for example, at an angle of about 45°. Vertical ridges  26  have less dramatic profiles. For example, the width of vertical ridges  26  preferably will be from about 2 to about 3 inches while the height will be from about 0.1875 to about 0.375 inches. The overall height of sides  23  and the extension of horizontal portions  23   c  and  23   d  may be diminished somewhat for narrower panels and increased somewhat for wider panels. Likewise, the number and dimensions of vertical ridges  26  may be varied accordingly. Workers in the art, however, having the benefit of this disclosure will be able to optimize the specific dimensions of the profile to provide greater or less stiffness as may be required for a particular application. 
     As noted, using spaced purlins as a cover support typically allows the cover to be fabricated and installed at lower cost. The profile of panels  20  is expected to provide them with load-resistance comparable to conventional trapezoidal, standing seam structural panels such as panels  120 , while providing them with other important advantages. As noted, panels  20  are symmetrical panels whereas panels  120  are asymmetrical panels. Thus, installation of panels  20  may proceed in either direction, and if damaged after installation in roof cover  10 , individual panels  20  can be replaced without removing any adjacent panels  20 . Asymmetrical panels  120  must be installed in a specific direction—either from left-to-right or right-to-left. Moreover, if a panel  120  is damaged and must be replaced, it must be reached by uninstalling panels  120  in the direction opposite to the direction in which they were installed. Thus, it may be necessary to uninstall and reinstall many undamaged panels  120  to replace a damaged panel  120 . 
     Moreover, the profile of panels  20  is simpler and allows them to be formed on smaller, less capable roll formers that can be transported to a job site. Because they can be formed on site, in most cases they can be run in lengths sufficient to cover the entire slope of the roof. Prior art panels  120 , however, because of their more complicated profile, require larger, more capable roll formers that are not easily transported to a job site. Thus, they must be fabricated in the factory and cut to transportable lengths. More often than not, those lengths are not sufficient to cover the entire slope of the roof. Multiple panels must be end lapped together to complete a run, and those end laps are potential sources of leading and are more susceptible to wind uplift. 
     Finally, it will be appreciated that proper modularity may be more easily maintained as the novel triangular standing seam panels are installed. Because of their profile, they do not tend to flex, accordion-like, in and out of their specified widths as do prior art trapezoidal standing seam panels. Moreover, prior art asymmetrical trapezoidal standing seam panels must be installed in a specific sequence, either left-to-right or right-to-left, and their profile requires that the clips be installed more or less at the same time that the panel is laid down. A modularity gauge typically must be employed to minimizes lateral flexing as the clips are installed. The novel triangular standing seam panels, however, are symmetrical. Their clips may be installed before the panels are laid down and seamed. Because the clips may be installed with precision, their placement helps maintain modularity of the novel panels as they are installed without the need for a modularity gauge. 
     The novel roof covers also may be installed over an existing roof cover. For example, as shown in  FIGS.  13 - 16   , novel roof cover  10  may be installed over a prior art metal roof  200 . Existing roof  200  is typical of exposed fastener metal roofs that have been installed in great numbers over the past few decades. As shown generally therein, it includes an array of spaced, elongated bar joists or purlins  61 . Purlins  61  are mounted on structural rafter beams (not shown) of a roof substructure and run horizontally through the roof. 
     As best seen in  FIGS.  14 - 16   , panels  220  in existing roof  200  run vertically across purlins  61  and have upturned longitudinal sides that overlap to form raised lap ridges  221 . Existing panels  220  also have, as is typical of panels of this type, a number of vertical ridges  226  formed in the trough  222  extending between lap ridges  221 . Panels  220  are supported by and attached to upper flange  64  of purlins  61  by penetrating fasteners, such as screws (not shown), which are installed in the troughs  222  of panels  220 . Panels  220  also are interconnected by screws or other penetrating fasteners (not shown) installed along overlapping lap ridges  221 . 
     Roof cover  10  is installed over existing roof  200  in a manner similar to the original installation of roof cover  10  exemplified above. Panel clips  30  and  40 , however, are arranged on the surface of existing panels  200 , and the fasteners, such as metal screws  13 , are driven though existing panels  220 . If desired, panels  220  of existing roof  200  may be further secured to purlins  61  or other support members with additional fasteners before installing roof cover  10 . 
     Preferably, clips  30  and  40  also are made somewhat taller to allow, as shown in  FIGS.  14 - 16   , the installation of foam board insulation  52  between existing panels  220  and panels  20 . Foam boards  52  have a generally flat, solid rectangular configuration such that they may be placed over existing panels  220  between adjacent rows of clips  30  and  40  with their sides closely abutting each other. The bottom surface of foam board  52  preferably is profiled to mate more or less with the profile of existing panel  220 . The bottom surface of foam boards  52 , therefor, will be able to rest more or less continuously across the surface of existing panels  220 , thus allowing any load transmitted to the foam to be distributed across a wider area. When foam boards  52  will be installed in areas where individual clips  30  are present, cutouts may be provided (not shown), if desired, to accommodate individual clips  30  and facilitate installation of foam boards  52 . Wider foam boards spanning across seam lines also may be provided with openings to accommodate individual panel clips. 
     Foam boards  52  preferably are composed of relatively dense high load capacity rigid plastic foam, such as expanded or extruded closed cell polystyrene. They may comprise facing, such as various barrier sheets, films, and coatings designed to provide a vapor barrier, to reflect radiant heat, or to provide fire resistance, or they may be unfaced. Typically, foam boards  52  will have a load capacity of from about 18 to about 25 pounds per square inch (psi). 
     It will be appreciated, however, that the novel roof covers may be installed over existing roof covers of various types in a variety of ways, and many conventional methods are known. For example, the novel roof covers may be installed over standing seam metal panel roof covers in a manner similar to recover systems disclosed in U.S. Pat. No. 8,938,924 to C. Smith. They may be installed over shingled roof covers in a manner similar to recover systems disclosed in U.S. Pat. No. 9,404,262 to C. Smith. Other methods are known and may be used. Moreover, although illustrated as being installed over an uninsulated existing roof cover, the novel roof covers may be installed of insulated roof covers. 
     Similarly, and as well understood by workers in the art, though referred to a “roof” panels, the novel panels and cover systems may use used to cover other surfaces of structures. If desired, for example, they may be used to cover walls of a building. 
     Finally, and for the avoidance of doubt, it will be appreciated that the terms “horizontal” and “vertical,” and forms thereof, have been used in two senses. In first senses, as applied to the orientation and layout of components within a cover system, the terms are understood in reference to the slope of the roof. “Horizontal” denotes that the component is oriented or runs across the slope of the roof, while “vertical” denotes that it is oriented or runs along the slope. In second senses, the terms are understood in reference to the plane of the roof, “horizontal” denoting extension in or generally parallel to the plane and “vertical” denoting extension generally perpendicular to the plane. Workers in the art commonly use the terms in both senses and will readily discerns the sense in which they are used in this disclosure. 
     While this invention has been disclosed and discussed primarily in terms of specific embodiments thereof, it is not intended to be limited thereto. Other modifications and embodiments will be apparent to the worker in the art.