Abstract:
A shear panel for constructing underlayments for floors and roofs of buildings includes a first rectangular layer of fire-resistant material, such as cementitious board, bonded to a second rectangular layer of thin high-strength material, such as galvanized steel. The length of the second layer is longer than the length of the first layer. The additional length of the second layer forms a tab extending from one end of the panel. During construction, a first panel is attached to a set of beams (floor joists or roof rafters) with the tab spanning between adjacent beams. A second panel is positioned on the beams with at least a portion of the second panel overlapping the tab of the first panel. The overlapping portion of the second panel is fastened to the tab of the first panel to form a continuous shear diaphragm for the floor or roof.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to fire-retardant panels for building construction, and, more particularly, is related to panels that are interconnected to form a continuous fire-resistant diaphragm for a floor or a roof of a building. 
     2. Description of the Related Art 
     Prevention of fires is an important aspect of building construction and use; however, fires do occur within buildings, and is important that any such fire be confined so that the fire does not spread throughout the building. Since flames and heat from combustion tend to expand upwardly, it is particularly important to inhibit or retard the spread of a fire between floors and to inhibit or retard a fire from penetrating the roof and spreading to other structures. 
     Various techniques have developed for reducing the spread of fire, particularly with respect to high-rise buildings. For example, the floors of such buildings may comprise a layer of corrugated metal with a layer of concrete poured over the metal. The beams supporting such floors are generally heavy steel I-beams, or the like, with sprayed-on fire retardant material. Typically, the space between the ceiling of one story of the building and the floor of the next higher story is a significant percentage of the height of each story. Because of the weight of such structures and because of the equipment required to erect such structures, such techniques are not economically or mechanically practical for smaller buildings having one to a few stories, such as, for example, smaller office buildings, condominiums, apartments, and the like, which are generally constructed using more manual labor and less large equipment. Furthermore, the amount of extra space needed to accommodate the covered beams and thick floor may result in unacceptably tall building. 
     Other techniques used for construction of smaller buildings require the construction crews to perform additional steps. For example, rather than simply laying down underlayment panels on the beams (e.g., floor joists or roof rafters) of a building, the construction crew may lay down a pattern of fire-retardant strips before laying down the panels. The strips cover the gaps between adjacent panels so that flames or heat from a fire do not penetrate the gaps. The additional material and labor required to align and install the strips increase the cost of constructing the building. 
     In addition to retarding of the vertical spread of fire, underlayment panels attached to support beams are used to provide shear resistance capacity that substantially reduces the lateral shifting of a building during earthquakes, high winds and other events that exert significant forces on the building. The fire-resistant material used to retard the spread of fire is generally not suitable for providing shear resistance capacity. Thus, additional construction steps are needed to provide both fire-resistance and shear resistance capacity. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, a need exists for improvements in the techniques for reducing the vertical spread of fire through the floors and through the roof of a building. Furthermore, a need exists for improvements in providing shear resistance capacity to the floors and roof of a building 
     In accordance with aspects of embodiments of the present invention, a shear panel for floors and roofs provides improved fire retardation and improved shear resistance capacity. The shear panel comprises a fire-resistant material bonded to a thin high-strength backing material (e.g., a metal such as, for example, galvanized steel). The shear panel is generally rectangular, and has a width defined between first and second edges and has a length defined between third and fourth edges. The width of the panel is selected so that when the panel is placed on conventionally spaced support beams (e.g., floor joists or roofing rafters spaced on 16-inch (40.64-centimeter) or 24-inch (60.96-centimeter) centers) with the first edge aligned with the centerline of a beam, the second edge is also aligned with the centerline of a parallel beam. In particularly preferred embodiments, the width is 48 inches (121.192 centimeters). When the first edge of a first panel is abutted to the second edge of an adjacent second panel along a beam, the seam formed between the two panels is blocked by the beam, thus creating a continuous fire retardant barrier across the seam when the two panels are secured to the beam. 
     The metal backing is continuous between the first and second opposing edges of the panel. The metal backing is also continuous between the third and fourth edges; however, the metal backing extends beyond the fourth edge to form a metallic tab along the fourth edge. When a third edge of a third panel is positioned proximate to the fourth edge of the first panel, a portion of the third panel proximate to the third edge overlies and rests upon the tab of the first panel. The third panel is secured to the tab of the first panel to close the seam between the two panels and form a fire retardant barrier in the space between the beams spanned by the two panels. 
     An aspect in accordance with embodiments of the present invention is a shear panel for floors and roofs that comprises a first layer of generally planar fire-resistant material, a second layer of high-strength backing material, and a bonding layer interposed between the first layer and the second layer to secure the second layer to the first layer. The first layer has a first surface and a second surface, which are generally rectangular. The shape of the first layer is defined by a first width between a first edge and a second edge of the second surface and by a first length defined between a third edge and a fourth edge of the second surface. The backing material has a generally rectangular shape. The shape of the backing material is defined by a second width between a respective first edge and a respective second edge of the second layer and by a second length between a respective third edge and a respective fourth edge of the second layer. The second width of the second layer is approximately equal to the first width of the first layer. The second length of the second layer is greater than the first length of the first layer by a selected distance. The first edge of the second layer is aligned with the first edge of the first layer. The second edge of the second layer is aligned with the second edge of the first layer. The third edge of the second layer is aligned with the third edge of the first layer. The fourth edge of the second layer is displaced from the fourth edge of the second layer by the selected distance to form a tab extending from the third edge of the first layer. 
     Another aspect in accordance with embodiments of the present invention is a shear panel for floors and roofs that comprises a generally rectangular first layer and a generally rectangular second layer bonded to the first layer. The first layer comprises a fire-resistant material. The second layer comprises a high-strength backing material. The first layer has a first width between respective first and second edges and has a first length between respective third and fourth edges. The second layer has a second width between respective first and second edges and has a second length between respective third and fourth edges. The second width is approximately the same as the first width, and the second length is greater than the first length by a tab length. The backing material is positioned on the first layer with the respective first edges aligned, with the respective second edges aligned, and with the respective third edges aligned. When the first, second and third edges are aligned, the fourth edge of the second layer is displaced from the fourth edge of the first layer by the tab length. The additional length of the backing material extends as a tab from the fourth edge of the first layer. 
     Another aspect in accordance with embodiments of the present invention is a method of forming a laminated shear panel for constructing floors and roofs of a building. The method comprises forming a first layer of a fire-resistant material into a first generally rectangular shape having a first width between a respective first edge and a respective second edge and having a first length between a respective third edge and a respective fourth edge. The method further comprises forming a second layer of a high-strength material into a second generally rectangular shape having a second width between a respective first edge and a respective second edge and having a second length between a respective third edge and a respective fourth edge. In accordance with the method, the second width is formed to be approximately the same as the first width, and the second length is formed to be greater than the first length by a tab length. The method further includes aligning the first edge of the second layer with the first edge of the first layer and aligning the second edge of the second layer with the second edge of the first layer. The method further includes aligning the third edge of the second layer with the third edge of the first layer to cause the fourth edge of the second layer to be displaced from the fourth edge of the first layer by the tab length. The method further includes bonding the first layer to the second layer to produce a laminated panel. 
     Another aspect in accordance with embodiments of the present invention is a method for constructing a fire-resistant and shear-resistant diaphragm on the floor or roof of a building. The method comprises positioning a first rectangular shear panel on a first set of at least three beams. The first shear panel has a width selected to correspond to a multiple of a center-to-center spacing of the beams. The first shear panel comprises a layer of fire-resistant material bonded to a layer of high-strength material. The layer of fire-resistant material has a first length between a first edge and a second edge. The layer of high-strength material has second length greater than the first length to form a tab proximate the second edge of the shear panel. The method further includes positioning a second rectangular shear panel substantially identical to the first rectangular shear panel on a second set of at least three beams. At least two of the beams of the second set of beams are also in the first set of beams. At least an overlapping portion of the second shear panel proximate to the first edge is positioned on the tab of the first shear panel. The method further includes securing the first shear panel to the first set of beams, and securing the overlapping portion of the second shear panel to the tab of the first shear panel. 
     Another aspect in accordance with embodiments of the present invention is a shear panel for constructing underlayments for floors and roofs of buildings. The shear panel includes a first rectangular layer of fire-resistant material, such as cementitious board. The first layer is bonded to a second rectangular layer of thin high-strength material, such as galvanized steel. The length of the second layer is longer than the length of the first layer. The additional length of the second layer forms a tab extending from one end of the panel. During construction, a first panel is attached to a set of beams (floor joists or roof rafters) with the tab spanning between adjacent beams. A second panel is positioned on the beams with at least a portion of the second panel overlapping the tab of the first panel. The overlapping portion of the second panel is fastened to the tab of the first panel to form a continuous shear diaphragm for the floor or roof. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The foregoing aspects and other features of embodiments in accordance with the present invention are described in more detail below in connection with the attached set of drawings in which: 
         FIG. 1  illustrates a perspective view of an exemplary shear panel in accordance with the present invention; 
         FIG. 2  illustrates an exploded perspective view of the panel of  FIG. 1  showing the two layers of the panel prior to bonding; 
         FIG. 3  illustrates an enlarged elevational view of the panel of  FIG. 1  in the direction of the lines  3 - 3  in  FIG. 1 ; 
         FIG. 4  illustrates a perspective view of an exemplary floor or roof of a building under construction, which illustrates a plurality of the panels of  FIG. 1  positioned on support beams (e.g., floor joists or roof rafters) in a first pattern in which the seams between the panels in the longitudinal direction of the beams are aligned and in which the seams in a direction perpendicular to the beams are also aligned; 
         FIG. 5  illustrates an enlarged elevational view taken along the lines  5 - 5  in  FIG. 4  to illustrate the abutment of two adjacent panels along the top of a beam; 
         FIG. 6  illustrates an enlarged cross-sectional view taken along the lines  6 - 6  in  FIG. 4  to illustrate the overlapping and mechanical interconnecting of the edge of one panel with the tab of an adjacent panel in the span between two beams; 
         FIG. 7  illustrates a perspective view of an exemplary floor or roof of a building under construction, which illustrates a plurality of the panels of  FIG. 1  positioned on the beams in a second pattern in which the seams between the panels in a direction perpendicular to the beams are aligned and the seams between the panels in the longitudinal direction of the beams are staggered; and 
         FIG. 8  illustrates a perspective view of an exemplary floor or roof of a building under construction, which illustrates a plurality of the panels of  FIG. 1  positioned on the beams in a third pattern in which the longitudinal seams between adjacent panels along the beams are aligned and the seams perpendicular to the beams are staggered. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIGS. 1 ,  2  and  3  illustrate an exemplary panel  100  in accordance with aspects of the present invention. The panel  100  is a laminated panel that comprises a first layer  110  of fire-resistant material, such as, for example, a cementitious material. For example, in certain embodiments, the first layer  110  comprises a non-combustible material such as Durock® brand underlayment available from USG Corporation headquartered in Chicago, Ill.; PermaBase® brand cement board available from National Gypsum Company headquartered in Charlotte, N.C.; and Hardiebacker 500® brand cement backerboard available from James Hardie Building Products in Mission Viejo, Calif. Other cement boards and boards comprising other non-combustible materials may also be used. 
     The first layer  110  has top surface  120  and a bottom surface  122  ( FIG. 2 ). In preferred embodiments, the first layer  110  has a thickness defined between the top surface  120  and the bottom surface  122  in a range from 0.5 inch (1.27 centimeters) to 1 inch (2.54 centimeters). Preferably, the thickness of the first layer  110  is a standard thickness for the building construction industry (e.g., 0.625 inch (1.59 centimeters) or 0.75 inch (1.9 centimeters)). 
     The shape of the first layer  110  is defined by the generally rectangular shapes of the top surface  120  and the bottom surface  122 . The first layer  110  has a width W 1  defined between a first edge  130  and a parallel second edge  132 . The first layer  110  has a length L 1  defined between a third edge  134  and a parallel fourth edge  136 . The width W 1  and the length W 2  are selected so that the panel  100  is sized to be compatible with the size of conventional 4×8 sheeting material used for building construction (e.g., a width of 4 feet (121.192 centimeters) and a length of eight feet (243.84 centimeters)). Although the panel  100  can be formed as a full 4×8 sheet, the weight of the cementitious material used for the first layer  110  may be 200-250 pounds (90.7-113.4 kilograms) for a 4×8 sheet having a thickness of approximately 0.625-0.75 inch (1.59-1.9 centimeters). Two or more construction workers may be needed to position each panel  100  during construction. In order to facilitate handling, the first layer  110  is configured as a square having a width W 1  of 4 feet (121.192 centimeters) and a length L 1  of 4 feet (121.192 centimeters) in the preferred embodiment of the panel  100  illustrated in  FIG. 1 . Thus, the weight of the first layer  110  in the illustrated embodiment is approximately 100-125 pounds (45.36-56.7 kilograms). 
     The cementitious material or other fire-resistant material used for the first layer  110  is generally quite brittle. Thus, the first layer  110  would not support a substantial load if the layer  110  were used alone to span between two beams (e.g., floor joists or roof rafters). Thus, as further illustrated in  FIG. 1 , and as shown more clearly in the exploded perspective view of  FIG. 2 , the panel  100  further comprises a second layer  140  that is bonded to the bottom surface  122  of the first layer  110 . The second layer  140  advantageously comprises a thin sheet of high-strength material, such as, for example, galvanized steel. Preferably, the second layer  140  has a thickness in a range from approximately 0.01 inch (0.254 millimeter) to approximately 0.1 inch (2.54 millimeters). More preferably, the second layer  140  has a thickness between a top surface  142  and a bottom surface  144  in a range from approximately 0.015 inch (0.381 millimeter) to approximately 0.06 inch (1.524 millimeters). In the illustrated embodiment, the second layer has a thickness of approximately 0.03 inch (0.762 millimeter), which generally corresponds to 22-gage. Although described herein as comprising galvanized steel, other suitable high strength materials may also be used. 
     In certain preferred embodiments, the second layer  140  is bonded to the first layer  110  in accordance with the method disclosed, for example, in U.S. Pat. No. 5,768,841 to Swartz et al. for Wallboard Structure. Preferably, the second layer  140  is bonded to the first layer  110  using a layer  150  of a suitable bonding material. Preferably, the bonding layer  150  comprises an adhesive, such as, for example, epoxy, glue, or the like. The adhesive is advantageously sprayed, brushed or rolled onto the bottom surface  122  of the first layer  110  or onto the top surface  142  of the second layer  140  or onto both in a conventional manner. The two surfaces are then forced together to permanently engage the two surfaces. Alternatively, the two surfaces can be bonded using double-sided tape or other suitable materials as the bonding layer  150 . The bonding layer  150  is illustrated in  FIG. 2  as being a separate layer spaced apart from the other two layers, such as in an embodiment utilizing double-sided tape or other sheets of adhesive material. In embodiments where the bonding layer  150  comprises an applied adhesive, the bonding layer  150  is only present as material applied to one of the other layers. 
     After the bonding is completed, the first layer  110 , the bonding layer  150  and the second layer  140  form the laminated panel  100 .  FIG. 3  illustrates an enlarged elevational view of a portion of the laminated panel  100  in the direction of the lines  3 - 3  in  FIG. 1  to show the laminated layers in more detail. 
     The laminated panel  100  has fire-resistant properties provided by the cementitious first layer  110  and has shear resistant properties provided by the high-strength second layer  140 . When installed on beams (e.g., floor joists or roof rafters), as described below, the second layer  140  also enables the panel  100  to span between beams and to support a load without breaking. 
     As shown in  FIG. 2 , the top surface  142  and the bottom surface  144  of the second layer  140  also have a generally rectangular shape. The second layer  140  has a width W 2  defined between a first edge  160  and a parallel second edge  162 . The second layer  140  has a length L 2  defined between a third edge  164  and a fourth edge  166 . The width W 2  of the second layer  140  is substantially the same as the width W 1  of the first layer  110  so that the respective first edges  130 ,  160  and the respective second edges  132 ,  162  are aligned when the two layers are bonded together as shown in  FIG. 1 . The length L 2  of the second layer  140  is greater than the length L 1  of the first layer  110 . When the third edge  164  of the second layer  140  is aligned with the third edge  134  of the first layer  110 , the fourth edge  166  of the second layer  140  extends beyond the fourth edge  136  of the first layer  110  to form a tab  170 . The tab  170  has a length L 3  corresponding to the difference in the second length L 2  and the second length L 1  (e.g., L 3 =L 2 −L 1 ). Preferably, the tab  170  extends along the entire width W 1  of the fourth edge  136  of the first layer  110 . In the illustrated embodiment, the length L 2  of the second layer  140  is in a range of approximately 4 feet 1 inch (124.46 centimeters) to approximately 4 feet 2 inches (127 centimeters). Thus, the tab  170  has a length L 3  in a range of approximately 1 inch (2.54 centimeters) to approximately 2 inches (5.08 centimeters). As described below, the tab  170  is used to interconnect adjacent panels in a structure to produce a continuous, fire-resistant and shear resistant diaphragm for a floor or a roof. 
     The first edges  130 ,  160  of the two layers  110 ,  140  in the laminated panel form a first edge  180  of the panel  100 . The second edges  132 ,  162  form a second edge  182  of the panel  100 . The third edges  134 ,  164  form a third edge  184  of the panel  100 . The fourth edge  136  of the first layer  110  corresponds to a fourth edge  186  of the panel  100 . Hence, the tab  170  extends from the fourth edge  186  of the panel  100 . 
       FIG. 4  illustrates a perspective view of an exemplary floor or roof of a building under construction, which illustrates a plurality of the panels  100  of  FIG. 1  positioned on a plurality of beams (floor joists or roof rafters)  210  in a first pattern  200 . Although the following description refers to the installation of the panels on a level pattern of beams, such as floor joists or the beams of a flat roof, it is understood that the description is equally applicable to installation of the panels on the rafters of a pitched roof. 
     In  FIG. 4 , the beams  210  are oriented longitudinally to form a horizontal flooring plane or a horizontal or pitched roofing plane. The centerlines of the beams  210  are mutually parallel and are spaced apart in the illustrated embodiment by 2 feet (60.96 centimeters) in a conventional manner. One skilled in the art will appreciate that in other construction applications, the centerlines of the beams  210  are spaced apart by 16 inches (40.64 centimeters). As discussed above, the width of the panels  100  accommodates both center-to-center distances. The beams  210  advantageously comprise steel or other suitable construction material. In the illustrated embodiment, the beams  210  have generally C-shaped cross sections with a width of approximately 2 inches (5.08 centimeters) and a height of approximately 8 inches (20.32 centimeters). Beams having other sizes and other cross sections can also be advantageously used in accordance with construction requirements. 
     As illustrated in  FIG. 4 , a first panel  100 A is positioned with its first edge  180 A on a first beam  210 A. The middle of the first panel  100 A rests on an adjacent beam  210 B. The second edge  182 A of the first panel  110 A rests on a next adjacent third beam  210 C. The second edge  182 A is aligned approximately with the centerline of the top of the third beam  210 C so that the first panel  110 A covers approximately a first half of the width of the third beam  210 C. For example, in an embodiment where the third beam  210 C has a nominal width of 2 inches (5.08 centimeters), the first panel covers approximately one inch (2.54 centimeters) of the width of the third beam  210 C. 
     A second panel  100 B is positioned next to the first panel  100 A so that the first edge  180 B of the second panel  100 B abuts the second edge  182 A of the first panel  100 A and so that the second panel  100 B rests on the second half of the top surface of the third beam  210 C. The abutment of the two panels  100 A,  110 B is shown in more detail in the enlarged elevational view in  FIG. 5 . 
     As shown in  FIG. 5 , the two panels  100 A,  100 B are secured to the third beam  210 C by a plurality of suitable fastening devices  220 , such as for example, sheet metal screws, which pass through the respective first layers  110 A,  110 B and through the respect second layers  140 A,  140 B of the two panels to engage the top of the third beam  210 C. Additional fastening devices  220  secure the first panel  100 A to the first beam  210 A and the second beam  210 B. 
     The middle of the second panel  100 B is secured to a fourth beam  210 D. The portion of the second panel  100 B proximate to its second edge  182 B is secured to the first half of a fifth beam  210 E. Additional panels  100  are positioned in like manner in alignment with the panels  100 A and  100 B to form a first row  230  of panels in the pattern of panels. For example, a portion of a third panel  100 C is illustrated in  FIG. 4  with its first edge  180 C abutting the second edge  182 B of the second panel  100 B. In the pattern illustrated in  FIG. 4 , the respective third edges  184 A,  184 B,  184 C of the panels  100 A,  100 B,  100 C are substantially aligned in a direction perpendicular to the longitudinal orientation of the beams  210 . Similarly, the respective fourth edges  186 A,  1868 ,  186 C are aligned in a direction perpendicular to the longitudinal orientation of the beams. 
     As further illustrated in  FIG. 4 , a second row  240  of panels  100  is positioned proximate the first row  230 . A fourth panel  100 D in the second row  240  has its first edge  180 D positioned on the first beam  210 A in alignment with the first edge  180 A of the first panel  100 A along the length of the first beam  210 A. The middle of the fourth panel  100 D rests on the second beam  2108 . The second edge  182 D of the fourth panel  100 D rests on the third beam  210 C and is aligned with the second edge  182 A of the first panel  100 A. 
     The fourth panel  100 D is secured to the three beams  210 A,  210 B,  210 C in the manner described above using additional fastening devices  220 . Additional panels  100  (not shown) are added as the construction progresses to complete the rows  230 ,  240  and to complete additional rows (not shown). 
     As shown in  FIG. 4  and as shown in more detail in the enlarged cross section in  FIG. 6 , the third edge  184 D of the fourth panel  100 D is positioned over the tab  170 A of the first panel  100 A so that the third edge  184 D abuts the fourth edge  186 A of the first panel  100 A. When positioned as shown, a portion of the fourth panel  100 D proximate the third edge  184 D rests on the tab  170 A. Additional fastening devices  220  pass through the first and second layers  110 D,  140 D of the fourth panel  100 D and engage the tab  170 A. When the fastening devices  220  are tightened, the tab  170 A of the first panel  100 A forms a secure, fire-resistant seal against the lower surface  144 D of the fourth panel  100 D. Furthermore, the secure interconnection of the two panels  100 A,  100 D effectively forms a continuous diaphragm spanning the two panels. Although the thickness of the tab  170 A of the first panel  100 A effectively raises the end of the fourth panel  100 D, the thickness of the tab  170  on each panel  100  is generally less than about 5 percent of the overall thickness of the respective panel. Thus, the additional thickness of the tab  170 A does not significantly affect the flatness of the floor or roof, particularly since other construction materials or finish materials cover the panels before the building is occupied. In particular, the pattern  200  of the panels  100  forms an underlayment (e.g., subfloor) over which additional flooring material, such as, for example, lightweight concrete flooring, gypsum cement flooring, hardwood flooring, flooring tile, carpeting, or the like, is installed to obtain a finished floor. Alternatively, the pattern  200  of panels  100  forms an underlayment for tiles, shingles or other roofing material. 
     When all the panels of the floor or roof underlayment system are interconnected in the illustrated manner to complete the pattern  200 , the continuous diaphragm resists shear forces in the horizontal plane of the floor or roof, such as, for example, lateral forces caused by earthquakes or high winds. Furthermore, since the thin second layers  140  of the panels  100  are bonded to the respective first layers  100 , the second layers  140  are secured to the beams  210  by the fastening devices  220  when the installation is completed. Thus, any permanent or transient loads applied to the panels in the areas between the beams  210  would have to bend the second layers  140  in order to fracture the first layers  110 . Any tendency to bend the second layers  140  is inhibited by the tensile strength of the galvanized steel or other high-strength material that forms the second layers  140 . Thus, such loads do not cause any significant vertical movement of the spanning portions of the panels  100  that would fracture the first layers  110 . 
     Even if the first layer  110  of a panel  100  is fractured by the impact of a dropped heavy object, any such fracture would not penetrate the high-strength material of the second layer  140 . Thus, the fracture would be constrained by the second layer  140  of the particular panel  100  and would not affect the efficacy of the diaphragm formed by the second layers  140  of the panels  100  in the flooring or roofing system. 
       FIG. 7  is a perspective view of an exemplary floor or roof of a building under construction, which illustrates a plurality of the panels  100  of  FIG. 1  positioned on the beams (e.g., floor joists or roof rafters)  210  in a second pattern  300 . The second pattern  300  has a first row  330  of panels  100 A,  1008 ,  100 C and has a second row  340  of panels  100  than includes a panel  100 D and a partial panel  100 E. As in the pattern  200 , the tabs  170  of the adjacent panels  100 A,  1008 ,  100 C in the pattern  300  are aligned so that the seams formed between the fourth edges  186  of the panels  100  in the first row  330  and the third edges  184  of the panels  100  in the second row  340  are aligned in the direction perpendicular to the beams  210 . The first edge  180 D of the panel  100 D in the second row  340  of the pattern  300  is staggered with respect to the first edge  180 A of the panel  100 A in the first row  330 . In particular, the panel  100 D is positioned in the second row  340  of the second pattern  300  with its first edge  180 D positioned approximately on the longitudinal centerline of the second beam  210 B rather than on the first beam  210 A so that the longitudinal seam along the third beam  210 C only extends for the length of the first panel  100 A before being interrupted by the fourth panel  100 D. The seam formed between the fourth panel  100 D and a fifth panel  100 E also extends only for the length of one panel. 
     Because of the offset of the first edge  180 D, only a first portion (e.g., approximately one-half) of the third edge  184 D of the panel  100 D abuts the fourth edge  186 A of the panel  100 A. A second portion of the third edge  184 D of the panel  100 D abuts the fourth edge  186 B of the panel  100 B. 
     In the embodiment illustrated in  FIG. 7 , the longitudinal seams between the panels of a third row (not shown) and every second row thereafter are aligned with the longitudinal seams of the panels in the first row. In another embodiment (not shown) with beams spaced apart by 16 inches (40.64 centimeters), the longitudinal seams are aligned in every third row. 
     In some applications, staggering of the longitudinal seams illustrated in  FIG. 7  further interlocks the panels  100  and may increase the shear strength of the overall floor or roof diaphragm. 
     Additional installation patterns may also be incorporated. For example, in a third installation pattern  400  shown in  FIG. 8 , the seams formed between the third edges  184  and the fourth edges  186  are staggered by offsetting the longitudinal positions of the second panel  100 B and other panels (not shown) in a second column  440  with respect to the first panel  100 A and the fourth panel  100 D in a first column  430 . In particular, the third edge  184 B and fourth edge  186 B of the second panel  100 B are displaced from the corresponding third edge  184 A and fourth edge  186 A of the first panel  100 A by approximately one-half the length of the panels. In  FIG. 8 , the third edge  184 C and the fourth edge  186 C of the third panel  100 C in a third column  450  are aligned with the corresponding third edge  184 A and fourth edge  186 A of the first panel  100 A. In other embodiments, the panels in adjacent columns are advantageously staggered by different distances (e.g., one-fourth of the panel length). 
     One skilled in art will appreciate that the foregoing embodiments are illustrative of the present invention. The present invention can be advantageously incorporated into alternative embodiments while remaining within the spirit and scope of the present invention, as defined by the appended claims.