Abstract:
Disclosed herein is an interlocking siding panel system for securing to the side of a structure with planar surfaces. When the panel is secured to the structure through the nail strip a full contact strip opposite the nail strip lays flat against the structure causing the panel portion below an point of inflection in the panel to raise up off of the structure creating a gap to facilitate movement of moisture past a locking leg that integrates with the panel below.

Description:
FIELD OF THE INVENTION 
     This disclosure pertains in general to a composite exterior siding panel that includes a system for interlocking panels that facilitate the downward movement of moisture away from the building structure. The disclosure also details how the system of interlocking panels limits the ability of wind to undermine the panels creating pressure differentials on the front and back surface that can dislodge the panel from the structure. 
     BACKGROUND OF THE INVENTION 
     Siding panels serve a two-fold objective of protecting a structure from damaging elements such as sunlight, moisture, hail and strong winds as well as providing an aesthetically appealing external appearance to the structure. The siding must be capable of protecting the structure from blisteringly hot sunlight that can induce thermal expansion and unattractive buckling of the siding. Siding produced from polyvinyl chloride (PVC) with organic and inorganic fillers has been shown to minimize thermal expansion and prevent or minimize the buckling of the siding when the solar heat load upon the structure is the greatest. The thermally stable siding is blended with high quality materials and is extruded with sufficient thickness to withstand large diameter hail impacts without permanent deformation. Panel siding must also minimize the infiltration of moisture from heavy wind blown rains and should moisture find its way behind the siding an exit route must be available to avoid the growth of mold and to prevent the rotting of any cellulosic structural elements such as plywood siding and structural framing or the oxidation of ferrous support members. 
     In addition to the capacity to withstand thermal loading, hail impacts and provide an escape route for moisture, well designed and installed exterior siding must be capable of withstanding high wind loadings. Siding panels that allow wind to gain access to the back surface, or the surface adjacent to the building structure, can experience tremendous loads capable of literally peeling the siding from the building. Consequently, the ability to seal both the upper and lower edges of the siding panel against panel courses above and below is critical to protecting the panels from the effects of strong wind loads. 
     Numerous siding panel designs exist in the market place; however, all are either lacking in some functional aspect or are prohibitively expensive, difficult to install or require extensive training and costly tools for proper installation. The consequence of such involved training and the acquisition of expensive tools is that these costs must ultimately be passed onto the consumer in order for the installer to experience a profit from her labors. 
     The product disclosed herein overcomes the adversities posed by wind, hail, rain, sun and complex installation procedures with a simple design that requires little training or sophisticated tools to properly install. In addition, the handsome wood grain exterior surface is aesthetically appealing with the warm textured feel of natural wood yet produced from a composite material that is highly resistant to fading, chipping, moisture damage, cracking and damage by insects. 
     It is an object of the invention to provide a composite exterior siding panel that is thermally stable and that will not buckle or warp even under the most extreme solar heat loads. 
     It is another object of the invention to provide an aesthetically appealing exterior surface that replicates a natural wood grain. 
     It is another object of the invention to provide a composite exterior siding panel that is lightweight and easy to install by an untrained homeowner with standard tools. 
     It is another object of the invention to provide a composite exterior siding panel that is tough, durable and capable of withstanding impacts from large diameter hail. 
     It is another object of the invention to provide a composite exterior siding panel that facilitates drainage of moisture trapped between the paneling and the building structure through weep slots in the rear face of the panel that start near the first flat and proceed past the inflection point of the panel. 
     It is another object of the invention to provide a composite exterior siding panel that includes a locking leg extending rearwardly from the back face of the panel and that also extends nominally downwardly toward the bottom edge of the panel and that extends longitudinally along the entire length of the panel. The locking leg creates a pocket for insertion of the top edge of a second panel disposed below the first panel to precisely define the positional relationship between the first and second panels. 
     It is another object of the invention to provide a composite exterior siding panel with a top portion and a bottom portion of a panel separated by an inflection point such that the top and bottom portions diverge at approximately 5 degrees so that when the panel is secured to the side of a structure at the nail strip the panel portion below the inflection point extends away from the building surface. In addition, when installed against a structural wall, the bottom surface of the locking leg is separated from the structural wall by a gap of from 0.020 to 0.060. The gap between the locking leg and the surface of the wall facilitates movement of moisture from upper panel courses to lower panel courses and ultimately to ground level thereby limiting contact with building surfaces that would deteriorate if exposed to the moisture for extended periods of time. 
     SUMMARY 
     The composite exterior siding panel with interlock system disclosure is directed to a panel capable of protecting a structure from damaging elements such as sunlight, moisture, hail and strong winds as well as providing an aesthetically appealing external appearance to the structure. In a preferred embodiment the siding panel comprises an extruded composite material of polyvinyl chloride that includes a combination of organic and inorganic fillers that increase the panel&#39;s durability, resistance to mold growth, resistance to deformation from hail impacts and overall structural strength. 
     The disclosed siding panel comprises a panel with a front face and a back face along with a top edge and a bottom edge. As is typical with siding panels, the panel course above partially overlaps the panel course below and the description below effectively outlines a system for building multiple courses of panels stacked atop and interlocking with one another on the side of a building. 
     The disclosed siding panel also includes a top portion of the panel and a bottom portion, the top and bottom portions of the panel diverge from one another at an inflection point. These diverging panel portions facilitate the formation of a path for moisture to travel between panel courses as will be discussed in greater detail below. The disclosed siding panel includes a flange extending substantially perpendicularly from the back face of the panel adjacent the bottom edge as well as a locking leg with a flat pad. The flange and locking leg with a flat pad run longitudinally along the entire length of the panel as do all features described below unless otherwise noted. 
     The locking leg backside in concert with the back face of the panel form a pocket for insertion of the top edge of a separate panel positioned in a lower panel course. The composite panel also includes a nail strip extending longitudinally along the entire front face of the panel proximate the top edge of the panel to be used in securing the panel to the wall with nails, screws and other securement means. The panel also includes a full contact strip extending longitudinally along the entire back face of the panel proximate the top edge of the panel which serves as the panel&#39;s only longitudinally extending area of contact with the wall surface. 
     After the first course of paneling is applied to the structure the pocket formed by the locking leg backside and the back face of the panel on the second course is positioned over the top edge of the first panel secured to the structure. Once the top edge of the first panel is positioned within the locking leg pocket of the second course, the second course is secured to the structure through the nail strip causing the full contact strip to lay flat against the structure. When a panel is secured to the structure at the full contact strip the entire back face of the panel below the inflection point, including the flat pad of the locking leg, raises off of the structure. Since no features of the back side of the panel below the inflection point are in contact with the wall surface an unobstructed path is created for moisture to flow downward with the aid of gravity. 
     Once moisture reaches the next lowest panel course it encounters the bottom edge of the first flat proximate the top edge of the panel where weep slots are installed to further facilitate the movement of moisture downward. The weep slots are installed with a separation distance of between 3 and 16 inches with a preferred diameter of about 3/16 inch. The weep slots originate proximate the bottom edge of the first flat and extend past the inflection point thereby allowing moisture to travel past the full contact strip which is firmly pressed against the wall by nails or screws passing through the nail strip. Failing to include weep slots would cause moisture to pool atop the first flat thereby potentially contributing to deterioration of the wall structure due to mold growth or structural member damage. Additionally, without weep slots moisture could become trapped behind the panel during a freeze thaw cycle thereby causing the moisture to expand and push the panels away from the structure loosening the connection to the building. 
     An additional feature of the disclosed panel is a flange extending substantially perpendicularly from the back face of the panel adjacent the bottom edge. When a second and further courses are installed the flat of the panel flange positioned above lands squarely and firmly on the front face of the lower panel course. The flange serves an aesthetic purpose of simulating a real wood panel that has sufficient thickness to overlap the panel course positioned below. Additionally, the flange serves to limit the intrusion of both high speed winds and wind blown moisture. High speed winds that enter beneath the bottom edge of panels that are not secured at the nail strip can catastrophically peel one or many panels from the wall surface. The flange effectively provides a wind and rain shield keeping the elements from intruding behind the panels and allowing the front face of the panel to provide protection for the structure. 
     Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing in which like numerals represent like components. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of the siding panels secured to the side of a building; 
         FIG. 2  is a perspective view of a portion of an embodiment of a single panel; 
         FIG. 3  is a side elevation view of an embodiment of a single siding panel; 
         FIG. 4  is a side elevation view of an embodiment of two interlocked siding panels; 
         FIG. 5  is a side elevation view of an embodiment of two interlocked siding panels secured to the side of a building; and 
         FIG. 6  is a rear perspective view of an embodiment of a single siding panel revealing a weep slot. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a structure  12  with several courses of exterior siding panels  10  installed thereon. The siding panels  10  can be extruded in many different widths with 4 and 7 inches the industry preferred panel widths. The panels are installed beginning at the lowest level and courses are installed progressively higher until the desired portion of the wall  38  is covered. The panels  10  are preferably extruded using a polyvinyl chloride composition with organic and inorganic fillers that contribute to thermally stabilizing the panels so that when exposed to intense solar heat the panels do not substantially expand and contract causing problems with panel buckling and loosening of the nails that anchor the panels  10  to the building wall  38 . The polyvinyl chloride in conjunction with the specially formulated organic and inorganic fillers produces a mechanically tough and resilient panel that is resistant to deformation from impacts such as hail and thrown objects as well as being resistant to insect damage and mold growth. 
     As seen in  FIG. 2 , the panel  10  is comprised of a front face  16  and a back face  18  opposite the front face. The front face  16  and the back face  18  are separated by a panel thickness  20  that is in the range of from 0.25 to 0.35 inches and preferably about 0.280 inches; however, this thickness may be optimized depending upon the width of the panel that is being produced. This thickness of the material provides sufficient structural rigidity to keep the panels from permanently deforming during severe hail storm events yet is sufficiently thin to minimize the weight of a long panel thereby facilitating ease of installation. The front face  16  of the panel is preferably texturized to simulate natural wood grain; however, smooth untexturized surfaces are also an option. 
     All features described below run the entire length of the panel  10  unless otherwise stated. As best seen in  FIGS. 3 and 4 , the panels include a top edge  22  and a bottom edge  24  opposite the top edge. The top of the panel  10  includes a first flat  26  angled at approximately 35 degrees from the plane of the back face  18  that, when installed, rests in the pocket  28  formed by the locking leg  30  of panel B as seen in  FIG. 4 , disposed immediately above the first panel A. The first flat  26  rests against the inner surface  64  of the locking leg  30  and is used to control the vertical positioning of panel B that is being positioned atop panel course A. On the opposite side of the top edge  22  from the first flat  26 , as seen in  FIG. 4  is a second flat  34  that when interlocked with panel B rests against the back face at  68  immediately below the locking leg  30 . The second flat  34  serves to further stabilize the bottom portion of panel B and provide the panel course located above with rigidity as it is disposed beneath the locking leg  30 . 
     Below the top edge  22  of the panel  10  is a point of inflection  36  separating the panel into a top portion  56  and a bottom portion  58  that directionally diverge from one another at an angle in the range of between 3 and 7 degrees. The inflection angle is preferably 5 degrees; however, this angle may vary depending upon the specific dimensions of the panel  10 . 
     At the bottom edge  24  of the panel  10  is a flange  40  extending substantially perpendicularly from the back face of the panel adjacent the bottom edge  24 . The flange  40  has a flange face  60  that when the panel is in position against the wall rests atop the front face  16  of the top portion  56  of the panel  10  as shown at reference number  74 . In addition to the flange  40 , and as previously discussed, is a locking leg  30  in proximity to the bottom edge  24  extending outwardly from the back face  18  and in the direction of the bottom edge  24 . The locking leg  30  includes a front side  62 , a back side  64  and a flat  66 . As discussed above, the locking leg back side  64  in conjunction with a segment  68  of the panel back face forms a pocket  28  for insertion of the top edge  22 , first flat  26  and second flat  34  of panel A positioned therebelow. The pocket  28  has a radius in the range of 0.040 to 0.080 inches and preferably a radius of 0.060 inches. 
     As best seen in  FIG. 5 , the bend in the panel at the inflection point  36  causes the lower portion of the panel  58  to rise up off of the wall  38  leaving the wall untouched by the panel beneath the inflection point  36 . Even the locking leg flat  66  remains out of contact with the wall  38  with the panel inflection producing a gap G between the wall and the locking leg flat  66  in the range of 0.025 to 0.0375 inches. This gap G between the locking leg flat and the wall is preferably 0.030 inches to facilitate the drainage of water down the wall  38  past the panel backside and the locking leg flat  66 . 
     As seen in  FIG. 2 , at the opposite end of the panel near the top edge  22  is a nail strip  44  that extends longitudinally along the entire front face  16  of the panel. The nail strip  44  has at its center a score line  46  into which the tips of nails should be hammered or screws threaded into the structural wall  38  behind the panel  10  as visualized in  FIG. 5 . On the back face  18  of the panel  10  opposite the nail strip  44  is a full contact strip  48  extending longitudinally along the entire back face  18  of the panel  10 . The full contact strip  48  has an upper boundary  70  and a lower boundary that is coincident with the inflection point  36  defining the width of the strip. The full contact strip  48  is a flat strip that rests against the wall  38  when the panel  10  is secured to the wall  38  with nails or screws. 
     As best seen in  FIG. 6 , weep slots  50  are also included on the back face  18  of the panel  10  to facilitate the transfer of moisture away from behind the panels. These weep slots  50  begin at the upper boundary  70  of the full contact strip  48  and extend downwardly past the inflection point  36  where they terminate in the panel bottom portion  58  away from the wall  38 . 
     In operation, a first course of paneling  10  is positioned against the lower level of the structural wall  38  and confirmed to be level. Next, nails, screws or other appropriate securement means are used to secure the full contact strip  48  of the first panel firmly against the wall  38  through the score line  46  in the nail strip  44  on the front surface  16 . As previously discussed, the panel  10  utilizes an inflection point  36  that produces directional divergence between the panel top portion  56  and the panel bottom portion  58  in the range of between 3 and 7 degrees and preferably at about 5 degrees. Consequently, nailing the panel to the wall  38  such that the full contact strip  48  is positioned against the wall  38  causes the panel bottom portion  58 , including the locking leg  30 , to raise up off of the wall  38 . Moisture can exit the area of the first flat  26  by passing through the weep slots  50  which are preferably spaced apart from 3 to 16 inches thereby giving trapped water an opportunity to escape. This moisture moves along the same path past each successive panel until it reaches the lower most surface of the structure where it is discharged to the ambient environment. 
     Once the first course A is secured to the wall, the locking leg  30  of the second course B is placed over the top edge  22  of the first course A. The locking leg of the second course panel effectively holds the second course in position atop the first course and since the first course A was previously leveled the second course B will remain level. The top edge  22 , first flat  26  and second flat  34  all cooperatively engage with the pocket  28  behind the locking leg  30  to form a rigid and secure interlock between successive courses of panels. 
     Another functional feature of the overall panel design is the flange  40  located at the bottom edge  24 . The flange face  60  serves to contact the top portion  56  front face  16  as shown at reference number  74 . The flange  40  also serves to prevent or greatly limit the infusion of air behind the panel  10  during strong wind events which can result in the panel being ripped from the surface  38  of the building. Additionally, the flange  40  greatly minimizes or prevents the infusion of water during rain storm and high wind events that can lead to water being trapped behind the siding saturating cellulose based building materials that can rapidly grow mold causing environmental as well as structural problems. 
     While the preferred form of the present invention has been shown and described above, it should be apparent to those skilled in the art that the subject invention is not limited by the figures and that the scope of the invention includes modifications, variations and equivalents which fall within the scope of the attached claims. Moreover, it should be understood that the individual components of the invention include equivalent embodiments without departing from the spirit of this invention.