Patent Publication Number: US-8109058-B2

Title: Building panel with a rigid foam core, stud channels, and without thermal bridging

Description:
PRIORITY APPLICATION 
     This is a non-provisional patent application that claims priority to a provisional patent application Ser. No. 60/849,863; filed on Oct. 5, 2006; by a common inventor. 
     This is a divisional of and claims priority to the non-provisional patent application Ser. No. 11/825,562, filed Jul. 5, 2007, by the same inventor. 
    
    
     BACKGROUND 
     1. Technical Field 
     This disclosure relates to insulated structural panels used in building construction. In particular, the present disclosure relates to insulated structural panels including a combination of structural metal components and rigid foam insulation. 
     2. Related Art 
     Traditional building construction typically uses wood or metal stud framing with fiberglass insulation enclosed with a drywall interior wall and a wood or stucco exterior wall. These types of conventional structures do not have efficient thermal insulating properties, use many types of non-recyclable materials, and are labor-intensive to build. 
     More recently, prefabricated panels made of two sheets of plywood or oriented strand board (OSB) with rigid foam insulation between the boards have been used to construct walls, floors, and/or roofs of buildings. These prefabricated panels, called “structural insulated panels” (SIP) may be fabricated at a manufacturing plant and shipped to a jobsite for rapid erection of a building. The SIP&#39;s are stronger and have better insulation properties than a framed lumber building. However, SIP&#39;s also have inefficient thermal insulation properties and can be susceptible to insect infestation, wood decay from excessive trapped moisture, mold, and/or mildew. 
     U.S. Patent Application Publication No. 20060117689, filed on Nov. 18, 2005, and names Ronnie and Yelena Onken as inventors (herein the Onken patent application) describes an insulated structural panel formed with a rigid foam core, a plurality of vertical hat channels on either face of the rigid foam core, and horizontal top and bottom L-channels on either face of the rigid foam core. The plurality of vertical hat channels on opposing faces of the rigid foam core is attached together so as to compress the rigid foam core, thus adding structural strength to the insulated structural panel. However, the ties used to attach the hat channels in the Onken patent application create undesirable thermal bridging between the opposing faces of the rigid foam core. This undesirable thermal bridging reduces the thermal insulation efficiency of the Onken panel. Further, the vertical hat channel described in the Onken patent application is expensive to manufacture and uses an excessive amount of material in the fabrication of the hat channel. 
     Typical existing SIP&#39;s that utilize a rigid foam core and hat channel studs often require a mechanical fastener. Typical existing SIP&#39;s that utilize rigid foam core and hat channel studs typically have a void between an opposing face of the studs to allow for the mechanical fastener between the parallel hat channels. This void makes it more difficult to attach interior and exterior sheathing. The mechanical fastener provides a thermal bridge and diminishes the insulating value of the panel making the structure less energy efficient. Typical SIP&#39;s that utilize a rigid foam core and hat channel studs have notches that are cut out of the foam. The overall insulating value of the panel is less than a panel without notches cut out. Typical SIP&#39;s that utilize a rigid foam core and hat channel studs are glued to adjacent panels, but the connection is still a hinge point with no structural value for bending. Consequently, the panel spans between the top and bottom plates or foundation. Typical SIP&#39;s that utilize a rigid foam core and hat channel studs typically have a glued butt connection at the corners. This butt connection is of minimal structural value and does not allow for ready attachment of interior sheathing. Typical SIP&#39;s that utilize a rigid foam core and hat channel studs require a stiffened lip to take advantage of the bending strength of the section, due to flange buckling effects seen in sections of this type 
     Thus, a structural insulated panel with a rigid foam core without thermal bridging is needed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments illustrated by way of example and not limitation in the figures of the accompanying drawings, in which: 
         FIG. 1  is a cutaway diagram illustrating an insulated panel according to an example embodiment. 
         FIG. 2  illustrates a straight panel according to an example embodiment. 
         FIG. 3  illustrates a curved panel according to an example embodiment. 
         FIGS. 4 and 5  illustrate a straight panel with studs in cross section showing the 4-bend stud according to an example embodiment. 
         FIG. 6  illustrates a corner lap in a particular embodiment. 
         FIGS. 7-9  illustrate a panel to panel connection (join) in a particular embodiment. 
         FIG. 10  illustrates a wood joist mounting at a panel in a particular embodiment. 
         FIG. 11  illustrates a drag truss at a panel in a particular embodiment. 
         FIGS. 12 and 13  illustrate a wood truss at an interior panel in a particular embodiment. 
         FIG. 14  illustrates a plywood web joist at a wall panel in a particular embodiment. 
         FIG. 15  illustrates an exterior strap holdown at a panel wall in a particular embodiment. 
         FIGS. 16 and 17  illustrate an interior wall with holdown in a particular embodiment. 
         FIGS. 18-31  illustrate an example embodiment of an inner corner joint and an outer corner joint in a particular embodiment. 
         FIG. 32  illustrates a plastic clip used to facilitate the insertion of studs, wiring, plumbing and the like into channels cut into the foam core of a panel. 
         FIGS. 33-34  illustrate the particular structure of the curved angle braces used with the curved panel in an example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A structural insulated panel with a rigid foam core without thermal bridging is disclosed. In the following description, numerous specific details are set forth. However, it is understood that embodiments may be practiced without these specific details. In other instances, well-known processes, structures and techniques have not been shown in detail in order not to obscure the clarity of this description. 
     As described further below, according to various example embodiments of the disclosed subject matter described and claimed herein, there is provided systems and methods for fabricating and using a structural insulated panel with a rigid foam core without thermal bridging. In a particular embodiment, the panel includes a 4-bend metal hat channel stud embedded in expanded polystyrene foam (EPS) and connected with metal angle braces at the edges to form a rigid panel suitable for the construction of buildings and the like. In particular embodiments, a novel panel is disclosed that has no thermal or sound bridge between the faces via mechanical fasteners. The disclosed panel of various embodiments is more cost efficient in terms of labor to manufacture and materials due to the absence of a requirement for mechanical fasteners between the parallel hat channel sections. Further, the disclosed panel is more suitable to attachment of interior sheathing and does not require the removal of large portions of foam to place the studs thereby lowering the insulating value of the panel. Further, the disclosed panel of various embodiments provides for composite action between the studs and the foam making the panel much stiffer than one that utilizes a mechanical fastener spaced at intervals along the axial length of the panel sections. Further, the disclosed panel of various embodiments provides a continuous locking connection between adjacent panels to facilitate the transfer of pending from one panel to the next allowing the panel to span in two directions instead of a one way span allowing the panel to carry substantially more load, thereby lowering the cost of materials, labor, and shipping. Further, the disclosed panel of various embodiments does not require the use of stiffeners or ties between studs; because, the rigid foam braces the flanges of the stud. Thus, the stud can be made less expensively with four bends instead of six. This helps not only with bending capacity of the stud but with compressive capacity of the design as well. Various embodiments are described below in connection with the figures provided herein. 
     Referring to  FIG. 1 , a cutaway diagram illustrates an insulated panel  100  comprising one or more studs  110  embedded in expanded polystyrene foam (EPS)  115  and connected with metal angle braces  120  at the edges to form a rigid panel  100 . In a particular embodiment, the studs  110  are each a 4-bend metal hat channel stud shown in cross-section in  FIGS. 4 and 5 . Each stud  110  is embedded in the EPS  115  so that only a single outer face of the stud  110  is substantially flush with the outer face of EPS  115 . Angle braces  120 , formed in a particular embodiment as an L-shaped member, are connected to studs  110  in a substantially perpendicular arrangement as shown in  FIG. 1 . Bolts, screws, or welds can be used to bind each stud  110  to the angle braces  120 . As shown in  FIG. 1 , the opposing angle braces  120  capture the EPS  115  at each edge. 
     As shown in  FIG. 1 , hat channel studs  110  are not attached to each other (as shown by reference  119 ) thereby eliminating the presence of a thermal or sound bridge between the faces of the panels. The hat channel studs  110  are embedded into the rigid foam  115  with minimal perturbation to the foam and may be slid into place in a void provided in rigid foam  115 . In some cases, a lubricating adhesive including a bonding agent can be used to facilitate sliding stud  110  into rigid foam  115  and locking stud  110  into rigid foam  115  via the adhesive agent. In a particular embodiment, hat channel stud  110  can be produced using no more than four bends to produce a stud with a hat channel shape in cross-section. In various embodiments, additional bends in stud  110  are not necessary as a sufficient level of stiffness is achieved using the structural properties of rigid foam  115  to fully brace the flanges of studs  110 . Because studs  110  in various embodiments described herein can be produced with no more than four bends, manufacture of the studs  110  in various embodiments is less expensive, less complicated, and uses less material to produce the stud  110 . 
       FIG. 2  illustrates a straight panel  100  with studs  110 , angle braces  120 , and rigid foam core  115 . An electrical or plumbing chase  117  is also shown as a cut-out portion of the foam  115 . 
       FIG. 3  illustrates a curved panel  101  with studs  110 , angle braces  120 , and rigid foam core  115 . An electrical or plumbing chase  117  is also shown as a cut-out portion of the foam  115 . 
       FIGS. 4 and 5  illustrate a straight panel  400  with studs  110  in cross section showing the 4-bend stud. In  FIG. 4 , a 2-bend flashing hat member  412  is also shown at both ends of the panel. A 3-bend hat member  410  is also shown at both ends of the panel. In  FIG. 5 , 2-bend flashing hat members  412 ,  415 ,  416 , and  417  are also shown at both ends of the panel. A lap joint with an expansive adhesive  414  is also shown at both ends of the panel. 
       FIG. 6  illustrates a corner lap  500  in a particular embodiment. A 2-bend flashing  502  is shown. A 2-bend flashing hat with third field bend  503  is also shown. A lap joint with an expansive adhesive  504  is also shown. A 3-bend hat member  505  is also shown. 
       FIGS. 7-9  illustrate a panel to panel connection in a particular embodiment. An exterior panel  601  is shown. Studs  602  are also shown. The assembly shown in  FIGS. 7-9  is used to join a second panel  605  to panel  601  in a perpendicular orientation. To accomplish this join, a side of panel  601  is fitted with a flat metal strap  607  that can be attached to panel  601  with metal screws or bolts  608  attached at studs  602  as shown in  FIGS. 7-9 . The join assembly shown in  FIGS. 7-9  includes an embedded fitting  606  that includes a first surface that is embedded into panel  605  and a second surface that is exposed at an end of panel  605 . In this manner, embedded fitting  606  is secured to panel  605 . As shown in  FIGS. 7-9 , an embedded fitting  606  is provided on both sides of panel  605 . The join assembly shown in  FIGS. 7-9  further includes a corner fitting  603  that includes a first surface positioned flush with the exposed surface of embedded fitting  606  and secured thereto with a metal screw or bolt. Corner fitting  603  includes a second surface positioned flush with the metal strap  607  on panel  601  and secured thereto with a metal screw or bolt. In this manner, embedded fitting  606  and corner fitting  603  can be used to secure panel  605  to panel  601  in a perpendicular orientation. 
       FIG. 10  illustrates a wood joist mounting at a panel in a particular embodiment. An edge nailing  701  is shown. A wood ledger  702  is shown. A shearwall sheathing  703  is shown. A wood joist  704  is shown. A conventional hanger  705  is shown. A block  706  is also shown. 
       FIG. 11  illustrates a drag truss at a panel in a particular embodiment. A drag truss  801  is shown. A conventional plate  802  is shown. A panel  803  is shown. A shearwall sheathing  804  is shown. 
       FIGS. 12 and 13  illustrate a wood truss at an interior panel in a particular embodiment. An edge nailing  902  is shown. A block  903  is shown. A top chord bearing truss  904  is shown. A wall panel  905  is shown. A shearwall sheathing  906  is shown. A block  907  is shown. 
       FIG. 14  illustrates a plywood web joist at a wall panel in a particular embodiment. A plywood web joist  1001  is shown. A panel and top track  1002  is shown. A variable pitch connector  1003  is shown. A top plate blocking  1005  is shown. 
       FIG. 15  illustrates an exterior strap holdown at a panel wall in a particular embodiment. A concrete slab or foundation  1101  is shown. A strap holdown  1102  is shown. A track anchorage  1103  is shown. A bottom track  1104  is shown. A panel stud  1105  is shown. Screws  1106  are shown. Exterior sheathing  1107  is shown. Screws  1108  embedded in sheathing  1107  and stud  1105  is also shown. 
       FIGS. 16 and 17  illustrate an interior wall with holdown in a particular embodiment. A panel  1201  is shown. The 3-bend members  1202  and  1203  are shown. A concrete slab  1204  is shown. A panel bottom track  1205  is shown. A track anchorage  1206  is shown. A C-stud  1207  is shown. Screws  1208  are shown. Interior sheathing  1209  is shown. A holdown  1210  is shown. 
     The new panel configuration of a 4-bend hat channel stud embedded in EPS substantially improves the vertical load carrying capacity of the embedded stud columns; because, the EPS acts to create a continuously braced column, which has much better load-bearing capacity. This improvement in load bearing capacity does not require connecting members between studs or a 6-bend stud. 
     An additional advantage of the disclosed panel of various embodiments is that the panel can use the expansive nature of the adhesive. The panels can be joined together and screwed with a lap as detailed above in connection with the drawings. As the glue sets, it attempts to force the panels apart putting the connection in tension. This tension minimizes the hinging that is seen between the panels allowing for beam action top to bottom and side to side. A simple example of this is a two way floor slab. A two way floor slab has reinforcement running in both directions and has multiples more load carrying capacity. The disclosed panel of various embodiments will make terrific floor and roof panels that will require far less beam support thereby making them much more efficient to use in these applications as well. 
     An additional advantage of the disclosed panel of various embodiments involves the lap at the ends. Here, in particular embodiments, a two and two with third field bend hats can be used. This makes all panels (save the electrical and plumbing chases) interchangeable. Having all panels interchangeable is highly advantageous as it makes the necessity for detailed shop drawings obsolete thereby saving time and cost. 
     An additional advantage of the disclosed panel of various embodiments involves the manner in which interior panels are anchored with post install hold downs as described above in connection with the figures. Having the ability to move a wall and not be concerned with being a couple of inches off could save a great deal in on-site labor and potential work stoppage. 
     The interaction between the studs and the panel can rely on friction. This action will be amplified once sheathing is added. The compression between the studs, as provided in conventional panel designs (e.g. the Onken patent application), is not necessary when there is enough friction between the channels and the studs to resist the shear that occurs when the panel is in bending. One additional advantage of having the studs embedded into the foam is that the foam is rigid enough to fully brace the flanges of the studs. In absence of the foam, the capacity in bending of the section is limited by local buckling of the flanges and is multiples less than having the flanges fully braced. In a similar fashion, the vertical load carrying capacity of the embedded stud columns is substantially increased as a continuously braced column depending on length and gauge. 
     An additional advantage of the disclosed panel of various embodiments is that the steel and the expanded polystyrene foam do not release off-gassing from resins, adhesives or chemicals normally used for wood construction. This creates less toxic residue at the manufacturing and building site. 
     An additional advantage of the disclosed panel of various embodiments is that the panels are fast and easy to install. Anyone can be trained in the site installation of the walls and roofs in just hours—not days, weeks or months. Thus, construction time is shorter and less expensive. 
     An additional advantage of the disclosed panel of various embodiments is that the panels are resistant to fire, natural disasters, earthquakes, hurricanes, mold, mildew, moisture, insects, rust, and warping. The panels provide diminished air pollutants and dust. Further, the panels are substantially stronger than wood panels and made from 100% recyclable non-toxic materials. 
       FIGS. 18-31  illustrate an example embodiment of an inner corner joint and an outer corner joint.  FIGS. 18-20  illustrate an inner corner joint comprising two components, a first inner corner joint component  1310  and a second inner corner joint component  1312 . As shown in  FIGS. 18-20 , first inner corner joint component  1310  is inserted or formed into an insulated panel  1311  at an inside corner of the insulated panel  1311 . Similarly, as shown in  FIGS. 18-20 , second inner corner joint component  1312  is inserted or formed into an insulated panel  1313  at an inside corner of the insulated panel  1313 . In this manner, a flat face of first inner corner joint component  1310  can be made flush with a flat face of second inner corner joint component  1312  when insulated panels  1311  and  1313  are joined at the corners at right angles as shown in  FIGS. 18-20 . When the flat face of first inner corner joint component  1310  is flush with the flat face of second inner corner joint component  1312 , the first inner corner joint component  1310  can be bonded to second inner corner joint component  1312  using a variety of means including, the use of bolts, screws, welds, glue, and the like. When first inner corner joint component  1310  is so bonded to second inner corner joint component  1312 , the inventive inner corner joint serves to securely hold the insulated panels  1311  and  1313  in a right angle alignment. 
       FIG. 30  illustrates a detail of the first inner corner joint component  1310  and the second inner corner joint component  1312 . These components can be fabricated from a variety of rigid materials including metal, composites, wood, and the like. 
       FIGS. 21-23  illustrate another embodiment of an inner corner joint comprising a single join component  1310  and a stud  110 . As shown in  FIGS. 21-23 , join component  1310  is inserted or formed into an insulated panel  1311  at an inside corner of the insulated panel  1311 . Similarly, as shown in  FIGS. 21-23 , stud  110  is inserted or formed into an insulated panel  1313  at an inside surface of the insulated panel  1313 . In this manner, a flat face of the join component  1310  can be made flush with a flat face of stud  110  when insulated panels  1311  and  1313  are joined at as shown in  FIGS. 21-23 . When the flat face of the join component  1310  is flush with the flat face of stud  110 , the join component  1310  can be bonded to stud  110  using a variety of means including, the use of bolts, screws, welds, glue, and the like. When join component  1310  is so bonded to stud  110 , the inventive inner corner joint serves to securely hold the insulated panels  1311  and  1313  in a right angle alignment. 
       FIGS. 24-26  illustrate an outer corner joint comprising two components, a first outer corner joint component  1410  and a second outer corner joint component  1412 . As shown in  FIGS. 24-26 , first outer corner joint component  1410  is inserted or formed into an insulated panel  1411  at an outside corner of the insulated panel  1411 . Similarly, as shown in  FIGS. 24-26 , second outer corner joint component  1412  is inserted or formed into an insulated panel  1413  at an outside corner of the insulated panel  1413 . In this manner, a flat face of first outer corner joint component  1410  can be made flush with a flat face of second outer corner joint component  1412  when insulated panels  1411  and  1413  are joined at the corners at right angles as shown in  FIG. 14A . When the flat face of first outer corner joint component  1410  is flush with the flat face of second outer corner joint component  1412 , the first outer corner joint component  1410  can be bonded to second outer corner joint component  1412  using a variety of means including, the use of bolts, screws, welds, glue, and the like. When first outer corner joint component  1410  is so bonded to second outer corner joint component  1412 , the inventive outer corner joint serves to securely hold the insulated panels  1411  and  1413  in a right angle alignment. 
       FIG. 31  illustrates a detail of the first outer corner joint component  1410  and the second outer corner joint component  1412 . These components can be fabricated from a variety of rigid materials including metal, composites, wood, and the like. 
       FIGS. 27-29  illustrate an alternative embodiment of an outer corner joint comprising two components, a first outer corner joint component  1414  and a second outer corner joint component  1416 . As shown in  FIGS. 27-29 , first outer corner joint component  1414  is inserted or formed into an insulated panel  1411  at an outside corner of the insulated panel  1411 . Similarly, as shown in  FIGS. 27-29 , second outer corner joint component  1416  is inserted or formed into an insulated panel  1413  at an outside corner and across an edge of the insulated panel  1413 . In this manner, a flat face of first outer corner joint component  1414  can be made flush with a flat face of second outer corner joint component  1416  when insulated panels  1411  and  1413  are joined at the corners at right angles as shown in  FIGS. 27-29 . When the flat face of first outer corner joint component  1414  is flush with the flat face of second outer corner joint component  1416 , the first outer corner joint component  1414  can be bonded to second outer corner joint component  1416  using a variety of means including, the use of bolts, screws, welds, glue, and the like. When first outer corner joint component  1414  is so bonded to second outer corner joint component  1416 , the inventive outer corner joint serves to securely hold the insulated panels  1411  and  1413  in a right angle alignment. 
       FIG. 32  illustrates a plastic clip  1710  used to facilitate the insertion of studs, wiring, plumbing and the like into channels cut into the foam core of a structural insulated panel. As shown, the clip  1710 , typically fabricated from a polyethylene material, is formed in a shape that can be inserted into a channel in the foam core of a structural insulated panel. A metal stud, brace member, wiring, or plumbing component can then more easily be inserted into the foam core of the structural insulated panel. 
     Referring back to  FIG. 3 , a curved panel  101  is illustrated with studs  110 , angle braces  120 , and rigid foam core  115 .  FIGS. 33-34  illustrate the particular structure of the curved angle braces  121  used with the curved panel  101 . Because the curved angle braces  121  must follow and be flush with the inner and outer curved surfaces of curved panel  101 , the curved angle braces  121  of one embodiment are notched at several locations as shown in  FIGS. 33-34  to enable bending of the rigid curved angle braces  121  without warping. The spacing and width of each notch can be varied depending on the needed level of curve. 
     Thus, a structural insulated panel with a rigid foam core without thermal bridging is disclosed. While the present invention has been described in terms of several example embodiments, those of ordinary skill in the art will recognize that the present invention is not limited to the embodiments described, but can be practiced with modification and alteration within the spirit and scope of the appended claims. The description herein is thus to be regarded as illustrative instead of limiting.