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

You are an expert at summarizing long articles. Proceed to summarize the following text: 
The present invention relates to a panel system and a method of installing a light weight structural system to provide a safe, long lasting, weatherproof, maintenance free surface. The panel may be a composite material with fiberglass reinforced polymer (FRP). It may be covered with a gel coat or a painted finish. The panel provides structural strength to support loads and forces as a combination roof and decking material as well a sidewall construction building panel. 
     BACKGROUND OF THE ART 
     The present invention is a non-metal panel system with advantages over known metal panel systems, metal panel foam laminate systems, FRP panel systems, and FRP foam combination panel systems. 
     Prior art metal panel roof systems are traditionally divided into two categories, architectural and structural. An architectural system is generally a steep slope system, used for visual impact or aesthetics. It typically requires a supporting deck with a minimum slope of 3 inch per foot of slope with water shedding or hydrokinetic seams. A structural system will tend to be a low slope system, although a minimum of ¼ inch per foot of slope is typically used to provide runoff. A structural system can support its own weight without a deck. The seams of a structural system are water tight or hydrostatic and are designed to withstand water pressure. 
     These types of metal panels and seams come in a variety of shapes and sizes. Panels profile or shapes can be of corrugated style design, trapezoidal rib, flat, or a specialty design. Seams may have an interlocking or meshing male/female design, although non-meshing ends covered with a cap are also used. The seams may be hand formed, roll formed, or brake formed. Types of seam can include flat, corrugated, trapezoidal rib, batten, vertical leg. The term “standing seam” is often used as a generic description for most kinds of metal roofing. It comes from the fact that the seams stand vertically upright above the panel flats. Because a standing seam located above the panel is therefore out of the path of water that is either shedding from the roof or ponding or accumulating on the roof, the standing seam provides superior waterproofing, even when a hydrostatic seal of the seam may fail. These panels may be attached to supporting substructures with through panel fasteners. A number of fastening means are known, but a common means is a simple bolt and washer assembly with a variety of sealing methodologies. There are a variety of other attachment methods that do not require penetration of the panel surfaces, such as the clip system described in U.S. Pat. No. 4,649,684 to Petree. Another non-penetrating fastener is that taught by Greenberg in U.S. Pat. No. 5,737,892. 
     The same type of panels and seaming techniques are used commonly in the sidewall panels of buildings as are used in roofs, although waterproofing is a reduced concern. These panels are of metals, such as steel, copper, aluminum, etc., of typical thicknesses about 0.015 inches to about 0.051 inches. Similar to this type of metal panel roof and wall construction is roof and wall panel construction composed of panels that contain an insulated core with outer- or inner metal skins with similar design profiles and patterns. 
     Today, fiberglass-reinforced polymer panel roof and wall panel construction is similar, if not identical to, metal panel roof and wall construction. A primary difference is that FRP panel or panel system does not use a through panel attachment methodology combined with a standing seam lateral adjoinment. Lateral flat panel seams and longitudinal flat seams often require a field applied sealant, especially in combination with some form of sealing member, such as a gasket. These seams are vulnerable to problems in field craftsmanship as well as the durability and maintenance of the sealant used. In other words, an otherwise acceptable or even superior FRP panel roofing system can result in complaints against the manufacturer due to factors beyond that manufacturer&#39;s control. One FRP panel system using through panel attachment methodology and flat overlap seams is described in U.S. Pat. No. 5,625,999 to Buzza. 
     Other plastic panel technology that has been developed in recent years includes the panel coupling assemblies of Conterno, assigned to Politec Polimeri Tecnici S. A. of Italy, as disclosed in U.S. Pat. No. 6,347,495 B1 (Feb. 19, 2002) and U.S. Pat. No. 6,202,382 B1 (Mar. 20, 2001). 
     It is a previously unmet object of the invention to provide a non-metal panel system that employs a non-penetrating method of attachment, to eliminate penetrating fasteners that are the source of leaks, which require routine maintenance to ensure their tightness or attachment and watertight seal and which restrain movement of the panel from expansion, contraction and other stresses. 
     SUMMARY OF THE INVENTION 
     This and other objects of the invention are provided by a panel system for attaching to a substructure of a roof or a wall. Such a panel system comprises at least one pair of adjacent panels and at least one clip for connecting each said pair of adjacent panels. Each of the panels comprises an elongate body with a base section having first and second side edges. A first leg is attached at a first end thereof at the first side edge and a second leg is attached at a first end thereof at the second side edge. These first and second legs extend generally perpendicularly from the base section. Each side edge further comprises a groove or channel. In order to attach the first leg of a first panel to the second leg of a second panel, each of the first and second legs has one of a complementary pair of mating means arranged at a second end therof. Each of the clips comprises a flat bottom that is arranged and designed to have a bottom surface fastened to the substructure. Each clip further has a left, a right and a central support member that extends from an upper surface of the flat bottom. Each of the left and right support members has an enlarged upper surface for bearing against the base section of a panel and receiving its weight. The central support member has a pair of outwardly extending tongues or tabs to be received in the channel or groove of the panels. At least one clip fits between each pair of the adjacent panels. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will best be understood when reference is made to the detailed description of the invention and the accompanying drawing, wherein identical parts are indentified by identical reference number and wherein: 
     FIG. 1 shows a cross sectional view of a first embodiment panel; 
     FIG. 2 shows a cross sectional view of ends of first embodiment panels being joined together; 
     FIG. 3 shows a cross sectional view of a second embodiment having an insulative hollowed or foam containing underlying inner core; 
     FIG. 4 shows a cross sectional view of ends of second embodiment panels being joined together; 
     FIG. 5 shows a clip being used to fasten a pair of first embodiment panels; 
     FIG. 6 shows a clip being used to fasten a pair of second embodiment panels; and 
     FIG. 7 shows a cross sectional view of two panels of a third embodiment of the present invention being joined by a clip. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows an end or cross section view of the panel  10  of a first embodiment of the present invention, it being understood that this cross sectional profile of the panel  10  is consistent throughout a longitudinal direction of the panel, that longitudinal direction extending normal to the plane of the drawing sheet. For that reason, the section depicted could occur anywhere along the longitudinal direction. The panel  10  comprises a generally U-shaped elongate body having a planar base section  12  with first and second vertical legs  14 ,  16 , one of the legs positioned at the two side edges of the base section, that is, the sides when viewed in the cross section view as presented. One of the vertical legs, in this case, first vertical leg  14 , has a first part  18  of a means  20  for mating disposed at a top end thereof. The other vertical leg, that is, second vertical leg  16 , has a second part  22  of the mating means  20  disposed at a top end thereof. In the partical embodiment shown, the first mating means part  18  is a female portion and the second mating means part  22  is a male portion. 
     The juxtaposition of two adjacent panels  10   a,    10   b  is shown in FIG.  2 . In the embodiment illustrated, the second mating means part  22  on panel  10   b  fits into the first mating means part  18  of panel  10   a,  forming the vertical standing seam. A longitudinal strip or band  24  of a resilient sealent of gasket can be applied to one of the mating faces of the first or the second mating means parts  18 ,  22  to render the seam water-tight. If this strip or band  24  is adhered to one of the mating means parts  18 ,  22 , it should not be adhered to the other, as adhesion to both the first and second mating means parts  18 ,  22 , could result in restraining the panels from expansion in the longitudinal direction, causing stresses in the panel. However, it is desirable that the strip or band  24  be maintained in compression by the mating of parts  18 ,  22 . 
     FIGS. 1 and 2 also show another feature of the panel  10 . Each side edge is also provided with a groove or channel  26 , intended to receive a tongue of a clip, as described in more detailed below. For structural integrity, as well as for facilitating the guiding of the panels  10  into place, each groove or channel  26  has a pair of built-up gussets  28 ,  30 , one of the gussets above the channel and the other below the channel. Also notable in FIG. 2 is the vertical channel  32  available for receiving an upstanding member of the clip used to secure the panel assembly to the roof. 
     FIGS. 3 and 4 are similar to FIGS. 1 and 2, but illustrate a second embodiment of the present invention. FIG. 3 shows an end or cross section view of the panel  110  of this second embodiment, it again being understood that this cross sectional profile of the panel  110  is consistent throughout a longitudinal direction of the panel, that longitudinal direction extending normal to the plane of the drawing sheet. For that reason, the section depicted could occur anywhere along the longitudinal direction. The panel  110  comprises a generally U-shaped elongate body, but the base section  112  is no longer a relatively thin plane, but is instead a top plane  113  with an underlying cavity  115 , bounded by a bottom plane  117 , the cavity being shown in FIG. 3 as being filled with an insulative foam  119 . The first and second vertical legs  14 ,  16  are identical to those in FIGS. 1 and 2, and they operate identically, with means  20  for mating comprising a first part  18  disposed at a top end of first vertical leg  14  and a second part  22  disposed at a top end of second vertical leg  16 . As in FIGS. 1 and 2, the first mating means part  18  is a female portion and the second mating means part  22  is a male portion. 
     The juxtaposition of two adjacent panels  110   a,    110   b  is shown in FIG.  4 . In the embodiment illustrated, the second mating means part  22  on panel  110   b  fits into the first mating means part  18  of panel  10   a,  forming the vertical standing seam. A longitudinal strip or band  24  of a resilient sealent or gasket can be applied to one of the mating faces of the first or the second mating means parts  18 ,  22  to render the seam water-tight. If this strip or band  24  is adhered to one of the mating means parts  18 ,  22  it should not be adhered to the other, as adhesion to both the first and second mating means parts  18 ,  22 , could result in restraining the panels from expansion in the longitudinal direction, causing stresses in the panel. However, it is desirable that the strip or band  24  be maintained in compression by the mating of parts  18 ,  22 . 
     FIGS. 3 and 4 also show another feature of the panel  110 . Each side edge is also provided with a groove or channel  26 , intended to receive a tongue of a clip, as described in more detail below. For structural integrity, as well as for facilitating the guiding of the panels  110  into place, each groove or channel  26  has a pair of built-up gussets  28 ,  30 , one of the gussets above the channel and the other below the channel. Also notable in FIG. 2 is the vertical channel  32  available for receiving an upstanding member of the clip used to secure the panel assembly to the roof. Additionally a gusset  34  is shown in the cavity  117  as providing support. In the second embodiment, the vertical channel is longer, as it extends significantly below the channel  26 . 
     One method of securing the panel  10  of the present invention to roof is shown in FIG. 5, where a clip  60  is disclosed and is shown in side section. The clip  60  can be a continuous member or it can be discontinuous, depending on the particular amount of support needed in a particular application. The clip  60  has a flat bottom  62 , which may be seated upon and secured to an underlying building member, such as a purlin (not shown). The clip also has three upstanding members extending up from the bottom. These are the left and right supports  64 ,  66  and a central support  68 . In the embodiment shown, the central support  68  terminates at an upper end in a pair of horizontal tabs  70  which fit into the channels  26  of the panel  10 , while upper surfaces  72  of the left and right supports provide support to the planar portion  12  of the panel. In at least one additional design, the central support could extend further upwardly into the vertical channel  32 , as is shown in broken lines as part  74 . Of course, other clip options are available for securing the panels to the building. As noted the clip  60  can vary in length and size, and may even be continuous in length spanning the entire gap between adjacent purlins. This type of clip design allows the panel to expand/contract over its length along the channels/grooves freely. In essence the panel and panel system is free floating in the longitudinal direction. Panel weight is borne by upper surface  72  and tabs  70 . 
     FIG. 6 shows a second clip  160  for securing the panel  110  of the present invention to a roof. This clip  160  is similar to clip  60 , but the central support  168  is significantly longer to account for the thicker base portion of the panel  110 . 
     It will be appreciated that the clips  60 ,  160  described do not require any penetration of the panels to secure them to the roof and the clips do not impede longitudinal movement of the panels along the clip, thereby allowing expansion, contraction, etc. of the panels. Similarly, a degree of lateral movement is also allowed by the clip design. 
     In the embodiment of the panel shown in FIGS. 3 and 4, the panel may have a plastic or resin portion comprising phenolic, epoxy, polyester, vinyl ester, and polyurethane resins among others. The fiberglass portion of the panel may include chopped strands of fiberglass, fiberglass rovings, a variety of fiberglass mats from wet laid process, woven, laminated, or stitch knitted, and variety of other processes including a variety of additional reinforcing materials such as polyester, carbon, KEVLAR, etc. In some embodiments, at least the exterior or weather bearing surface of the panel may be painted or covered with a gel coat. 
     The panel profiles envisioned by this disclosure may formed by continuous methods such as extrusion, pultrusion, or by a variations thereof in lengths of example of 50 to 100 feet or more, limited only by the equipment used to form and handle the panels. Other finite methods of forming include variations of forms of molding such as open mold, spray lay-up, or closed molding. Resins can include both thermosetting of thermoplastic materials. 
     Even a third embodiment of the invention, exemplified by panel  210 , is shown in FIG.  7 . It is again understood that the cross sectional profile shown of the panel  210  is consistent throughout a longitudinal direction of the panel, that longitudinal direction extending normal to the plane of the drawing sheet. Actually, FIG. 7 shows two panels  210   a,    210   b  juxtaposed as they would be in operation, using a clip  300 , especially a clip similar to that disclosed in the Petree &#39;684 patent cited above. The panel  210  comprises a generally U-shaped elongate body, but the base section  212  is not a relatively thin plane, as in panel  10 , but is instead a top plane  213  with an underlying cavity  215 , bounded by a bottom plane  217 . Unlike the embodiment in FIG. 3, the embodiment in FIG. 7 is not filled with an insulative foam, although it certainly would be in some embodiments of the invention. The base section  212  is bounded on its ends by first and second vertical legs  214 ,  216 , one of each being shown on the respective panels  210   a,    210   b.  The first vertical leg  214 , has a first part  218  of a means  220  for mating disposed at a top end therof. The other vertical leg, that is, second vertical leg  216 , also has a first part  218  of the mating means  220  disposed at a top end thereof. It is noted that the first mating parts  216 ,  218  of the respective vertical legs are identical, although mirror images of each other. They do not mate with each other. To achieve the mating of the first mating parts, a second mating part  222  is required and this is provided by cap member  302 , shown operatively engaged on the panels  210   a,    210   b.  In the particular embodiment shown, the first mating part  218  are male portions and the second mating part  222  is a female portion. 
     The embodiment shown in FIG. 7 does not show any equivalent of the longitudinal strip or band  24  of a resilient sealant or gasket which is applied to mating faces in the first two embodiments. This does not mean that such a resilient sealant or gasket would not be used. However, if the sealant or gasket were used, the primary place for positioning it would be along the V-shaped gap between the cap member  302  and the tops of mating parts  218 . Alternately, it would be desirable in some situations to use a T-shaped gasket in which the horizontal arms would lie in the V-shaped gap and the vertical arm would extend in the vertical gap between the mating parts  218 . 
     FIG. 7 also shows other features of the panel  210  and clip  300 . Each side edge is also provided with a groove or channel  226 , intended to receive a tongue  304  of the clip, but in this case the groove  226  is formed in the first mating part  218  at the top end of the vertical leg  214 ,  216 , rather than at an intermediate portion of the leg, especially an intermediate portion near the base section  212 . In this way, the built-up head  240  of the first mating part  218  acts as a gusset similar to one of the gussets  28 ,  30  of the other embodiments and the functionality of the second gusset is provided by a portion of the cap member  302 , specifically part  306 . 
     A few points are in order about cap member  302 . The cap member would usually be selected from a rigid plastic material, but the material should be selected so that the channel opening  308  may selectively expand as the cap member  302  is pushed downwardly onto the respective first mating parts  218 , but resiliently restore to this initial size once engaged. To help achieve this, one known method is to have a portion  308  of the cap member be less thick than other portions, so that some flexibility is provided at that point.

Summary:
A light-weight structural system is provided by a panel system having at least one pair of adjacent panels ( 10 ) and a clip ( 60 ) positioned between the adjacent panels. A groove or channel ( 26 ) in each panel receives an outwardly-extending tongue or tab ( 70 ) on the clip. Built-up gussets ( 28, 30 ) on the panels above and below the groove or channel provide structural strength. Upwardly-extending support members ( 64, 66 ) on the clip bear weight from the panels. A base section ( 62 ) of the clip allows the clip to be fixed to a roof or wall substructure. The panels can be formed from thermosetting or thermoplastic polymers, especially fiber-reinforced polymers.