Abstract:
A roof seam fastener system including a mechanical fastener member for mechanically attaching a roof membrane to a roof structure. The roof seam fastener system comprises a fastening assembly that creates a seal to either the roof membrane or a roofing substrate located directly below the fastening assembly. This fastening assembly also creates a seal against the mechanical fastener member. This combination results in redundancy which prevents any water penetration into the seam from entering the roofing envelope. The roof seam fastener system improves wind uplift resistance of the roof membrane and minimizes other weather related damage.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates in general to a mechanical attachment system for securing roof membranes, and more particularly, to a mechanical attachment system for securing roof membranes wherein a seal is achieved between the mechanical attachment device and the roof membrane and/or material directly below it, minimizing weather related damage. 
         [0003]    2. Description of Related Art 
         [0004]    Single-ply roofing systems are typically installed using three basic methods: ballasted, fully adhered, and mechanically attached. Mechanically attached single-ply roof membranes are attached to a structure using various types of metal and plastic fasteners which are installed through strips or plates made from metal, plastic or a combination of the two. 
         [0005]    One typical installation method is illustrated in  FIG. 1 . In this method, a roof membrane substrate  2  is positioned adjacent to a roof decking  4 . A first sheet of roofing membrane  6  having a first edge  8  is laid onto the roof membrane substrate  2 . A fastener assembly, generally illustrated as  10 , is installed along this first edge  8  of the first sheet of roofing membrane  6  to secure the roofing membrane  6  to the roof membrane substrate  2 . The fastener assembly  10  comprises a clamping device  12 , which is positioned on top of the first edge  8  of the first roofing membrane  6 , and a fastener  14 , such as a nail, screw or the like. The fastener  14  extends through the clamping device  12 , first roofing membrane  6 , and roof membrane substrate  2  and then into the roof decking  4 . An adjacent or second sheet of roofing membrane  16 , having a second edge  18 , is then applied such that this second edge  18  overlaps the first edge  8  of the first membrane  6  and the fastener assembly  10 . A portion  9  of the first edge  8  and second edge  18  of the overlapping first and second membranes  6 ,  16  are then seamed together  20 . This seam can be created by any well known process such as heat, contact adhesives, self-adhering tapes, solvents, ultrasonic welding, dielectric welding, radio frequency welding or the like. Air and/or moisture vapor can be trapped between the second roofing membrane  16  and the roof membrane substrate  2 . 
         [0006]    Although this method of attaching a roofing membrane is commonly used, there are several drawbacks to this attachment method. As shown in  FIG. 2 , this particular method is susceptible to failure caused by uplift forces  11  during wind loads or constant positive pressure loads due to asymmetrical loading, as shown by arrow  13 , of the fastener assembly  10 . The asymmetrical loads cause crushing of the roof membrane substrate  2 , due to the fastener  14  rocking under the load, immediately below the roof membranes  6 ,  16 . Once this occurs, the compression of the fastener assembly  10  against the roof membrane substrate  2  is lessened. This compression is necessary to prevent the roof membranes  6 ,  16  from slipping and tearing around the fastener  14 . Another disadvantage of this system is that the seam  20  also experiences a significant amount of peeling force, as shown by arrows  15   a  and  15   b.    
         [0007]    In an attempt to overcome the difficulties of this roof membrane attachment method shown in  FIGS. 1 and 2 , manufacturers have begun to create an additional or second seam  22 , for joining a portion  24  of the second roofing membrane  16  to a portion  25  of the first roofing membrane  6 , as shown in  FIG. 3 , on the opposite side of the fastener assembly  10 . Accordingly, the roof membranes  6 ,  16  are seamed along both sides of the fastener assembly  10  so that any uplift forces  11  caused by wind, as shown in  FIG. 4 , are applied symmetrically, as shown by arrows  17   a ,  17   b  and  17   c , to the fastener assembly  10 . This symmetrical application of force prevents crushing of the membrane substrate  2  and eliminates peel forces which can be exerted on the seams  20 ,  22 . Accordingly, the forces acting on the seams  20 ,  22  are in a shear mode instead of peel forces. This results in increased seam performance. 
         [0008]    As illustrated in  FIG. 5 , in an effort to reduce labor costs, rolls of the roofing membrane  6 ,  16  may be factory seamed together at  26  prior to delivery to the project site to create large panels, generally indicated as  28 . The overlap of the membranes  6 ,  16  is sufficient so as to create a fastening tab  30 . These panels of roofing membrane  28  are laid onto the roof membrane substrate  2 . A portion of the roofing membrane  16  is lifted upward so that the fastener assembly  10  can be installed through the fastening tab  30 . Although this method offers labor saving during the installation, it is still subject to the asymmetrical loading and peel force described above and illustrated in  FIG. 2 . In order to overcome the problems of asymmetrical loading and peel force, this method can include a second seaming operation performed on site after the application of the fastening assembly  10 , as described above with respect to  FIG. 3  and shown again in  FIG. 6 . 
         [0009]    As an alternative to the seam overlap attaching methods discussed above, another method for attaching a roofing membrane to a roof membrane substrate is shown in  FIG. 7 . This method includes the use of a supplemental member  32  formed of a compatible material located beneath a roof membrane  34  which are attached to the roof membrane substrate  2 . The fastener assembly  10  secures this supplemental member to the roof membrane substrate  2 . The supplemental member  32  can have a circular shape or any other shape. The roof membranes  34  are overlapped sufficiently to allow a seam and then attached on their underside via seams  35 ,  36  to the supplemental member  32  by using one of the seaming methods described above. One advantage of this method is the ability to locate fastener assemblies independent of the roof membrane overlaps. This can be particularly advantageous when the rolls of roof membrane are excessively wide or too narrow in relation to the attachment pattern required to secure the roof membrane to the structure. Another advantage is that the fastener  14  does not penetrate the roof membrane  34  and thus symmetrical loading of the fastener assembly  10  is achieved and the seam is oriented such that forces exerted thereon are in a shear mode as opposed to a peel mode. 
         [0010]    Another variation of this method is shown in  FIG. 8  where roof membrane panels  38  are overlapped sufficiently to allow seaming and installing of the fastener  14  of the fastener assembly  10  through the roof membrane into the roofing membrane substrate  2  and the roof decking  4 . The supplemental member  32  can be a circular (or any other shape) piece of roof membrane (or other compatible material) which is placed over the fastener assembly  10  and seamed at  39 ,  40  to the roof membrane  38 . A drawback to this method is the significant number of individual supplemental members  32  required to make the roof membrane  38  watertight. 
         [0011]    The roof membrane  38  can also be attached to the structure utilizing a linear fastener assembly  10  that is independent of the seam overlaps as shown in  FIG. 9 . This method is similar to that discussed above and shown in  FIG. 7 . However, instead of individual attachment patches, the fastener assembly  10  is installed through a longitudinal attachment strip  42 . The longitudinal attachment strip  42  has a width which is sufficient to overlap the fastener assembly  10  and to allow areas for seams  39 ,  40  to the roof membrane  38 . Panels of the roof membrane  38  are overlapped sufficiently to form seams  39 ,  40  and then attached along its underside to longitudinal attachment strip  42  using one of the seaming methods discussed above. 
         [0012]      FIG. 10  shows another variation for attaching the roof membrane panels  38  which is similar to that discussed above and shown in  FIG. 8 . This method also involves overlapping the roof membrane panels  38  sufficiently to allow seaming and installing the fastener assembly  10  through the roof membrane to the roof membrane substrate  2  and roof decking  4 . This method differs from the method discussed with respect to  FIG. 8  in that the roof membrane panels  38  are attached utilizing a longitudinal attachment strip or cover strip  42  as shown and discussed with respect to  FIG. 9 , rather than individual supplemental members. The linear fastening system is positioned over the fastener assembly  10  and is seamed at  39 ,  40  to the membrane panels  38 . This method can minimize the number of patches required and can allow the use of automated welding devices. 
         [0013]    While all of the methods discussed above and currently in use initially create a watertight system, they do not prevent subsequent damage that may be the result of cyclic loads resulting from wind or damage to the roof membrane due to natural phenomenon or abuse. There is a need in the art for fastening assembly that addresses these issues and prevents moisture or air from moving within the roof assembly, minimizing any weather related damage to the roof membrane substrate and roof decking. 
       SUMMARY OF THE INVENTION 
       [0014]    It is therefore an object of the invention to provide a mechanical attachment system for securing a roof membrane to a roof structure that creates a watertight system that reduces subsequent wind damage and other weather related abuse. It is a further object of the invention to provide a mechanical attachment system that prevents moisture or air from moving from the roof envelope to the seam channel or from the seam channel to the roof envelope. 
         [0015]    Accordingly, the present invention is directed to a roof seam fastener system, including a mechanical fastener member, for mechanically attaching a roof membrane to a roof structure, wherein the roof seam fastener system comprises a fastening assembly that creates a seal to either the roof membrane or a roofing substrate located directly below the fastening assembly. This fastening assembly also creates a seal against the mechanical fastener member. According to a first embodiment, the fastening assembly comprises a clamping plate having at least one washer laminated on one or both sides thereof. The fastener member includes a shaft extending through the clamping device and the at least one washer. The washer creates a seal with the roofing membrane and/or the roofing substrate as well as the shaft of the fastener member. According to a second embodiment, the fastening assembly comprises a clamping plate and a joining material positioned adjacent to the clamping plate. This joining material can comprise a field applied sealant or adhesive material. According to a third embodiment, the fastening assembly comprises a clamping plate having a washer laminated on one or both sides thereof or washers placed loosely on the top and or bottom of the plate. The fastening assembly may be positioned either above or below the roof membrane. 
         [0016]    These and other features and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in the specification, the singular form of “a”, “an”, and “the” includes plural referents unless the context clearly dictates otherwise. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  shows a mechanical attachment system for attaching a roof membrane to a roof substrate according to the prior art; 
           [0018]      FIG. 2  shows the wind effects of the mechanical attachment system of  FIG. 1 ; 
           [0019]      FIG. 3  shows an alternative mechanical attachment system for attaching a roof membrane to a roof substrate according to the prior art utilizing a double seam; 
           [0020]      FIG. 4  shows the wind effects of the mechanical attachment system of  FIG. 3 ; 
           [0021]      FIG. 5  shows another mechanical attachment system for attaching a roof membrane to a roof substrate according to the prior art using rolls of roofing material pre-seamed together; 
           [0022]      FIG. 6  shows yet another mechanical attachment system for attaching a roof membrane to a roof substrate according to the prior art using pre-seamed, double seamed membrane material; 
           [0023]      FIG. 7  shows another mechanical attachment system for attaching a roof membrane to a roof substrate according to the prior art using attachment discs positioned below the roof membrane; 
           [0024]      FIG. 8  shows another mechanical attachment system for attaching a roof membrane to a roof substrate according to the prior art using attachment discs positioned above the roof membrane over the fastening assembly; 
           [0025]      FIG. 9  shows yet another mechanical attachment system for attaching a roof membrane to a roof substrate according to the prior art using strips of attachment material positioned below the roof membrane; 
           [0026]      FIG. 10  shows still another mechanical attachment system for attaching a roof membrane to a roof substrate according to the prior art using strips of attachment material positioned above the roof membrane over the fastening assembly; 
           [0027]      FIGS. 11   a  and  11   b  show the mechanical attachment system of the present invention according to a first embodiment; 
           [0028]      FIGS. 11   c  and  11   d  show expanded views of the attachment system of  FIGS. 11   a  and  11   b;    
           [0029]      FIG. 12   a  shows the mechanical attachment system of the present invention according to a second embodiment; 
           [0030]      FIG. 12   b  shows an expanded view of the attachment system of  FIG. 12   a;    
           [0031]      FIG. 12   c  shows the mechanical attachment system of the present invention according to a third embodiment; 
           [0032]      FIG. 12   d  shows an expanded view of the attachment system of  FIG. 12   c;    
           [0033]      FIG. 13  shows the mechanical attachment system of the invention in practice according to a first arrangement; 
           [0034]      FIG. 14  shows the mechanical attachment system of the invention in practice according to a second arrangement; and 
           [0035]      FIG. 15  shows the mechanical attachment system of the invention in practice according to a third arrangement. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    For purposes of the description hereinafter, spatial or directional terms shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations, except where expressly specified to the contrary. It is also to be understood that the specific components illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. 
         [0037]    Now reference is made to  FIGS. 11   a - 11   d  which show the mechanical attachment system according to a first embodiment of the invention. In this embodiment, a fastening system, generally indicated as  50 , comprises a clamping plate  52  and a fastening member  54 . A washer  56  is positioned adjacent to the clamping plate  52  and is clamped between the clamping plate  52  and the material located directly below the clamping plate  52 . The clamping plate  52  can be formed from a metal or plastic material or any other material having sufficient strength to perform a clamping function. The washer  56  can be formed from a flexible and/or compressible material, such as a rubber or plastic material or any other well known material used for forming washers. The washer  56  can be clamped between the clamping plate  52  and a roof membrane  58 , as shown in  FIGS. 11   a  and  11   c . Alternatively, the washer  56  can be laminated to the clamping plate  52  to form a washer/clamp plate assembly  57  prior to application to a roof membrane  58 . The washer  56  can be laminated by any well known means, such as heat welding or the application of a separate adhesive material. The washer  56  forms a seal  65  to the underlying surface. This underlying surface can comprise either the roof membrane  58  or a roof substrate  59  in the situation illustrated in  FIG. 14  wherein the fastening system  50  is attached between the roof membrane  58  and the roof substrate  59 . 
         [0038]    The fastening member  54  can comprise a threaded fastener having a shaft  60 . The washer  56  can include a preformed first aperture  62 . A corresponding or second aperture  64  is also formed in the clamping plate  52 . The shaft  60  of the fastening member  54  extends through apertures  62 ,  64  to secure the fastening system  50  to the roof membrane  58 . The first aperture  62  has a first diameter which is smaller in size than a second diameter of second aperture  64 . Through this aperture  62 , a seal  63  is created between the washer  56  against the fastener shaft  60 . As an alternative to the preformed aperture  62  in the washer  56 , the washer  56  can be a solid member and the shaft  60  of the fastening member  54  penetrates the solid washer  56  during installation. 
         [0039]    A second washer can be applied to a top surface of the clamping plate  52 . This second washer allows for additional seaming or sealing against the fastener shaft  60 . This second washer is also useful in situations where the roof membrane  58  is positioned above the fastening system  50 , such as illustrated in  FIG. 14 . In the event that the second washer does not seal against the fastener shaft  60 , a grommet may be used directly beneath a fastener head  70  of the fastening member  54 . 
         [0040]    A second embodiment is illustrated in  FIGS. 12   a  and  12   b  which show the use of a joining material  72  between the clamping plate  52  and the roof membrane  58 . This joining material  72  creates a seal  90  against the fastener shaft  60  and the roof membrane  58 . The joining material  72  can comprise a sealant, adhesive, tape, caulking and any other material capable of creating a seal. This joining material may be pre-applied to the clamping plate or it may be applied at the field during installation. 
         [0041]    A third embodiment is illustrated in  FIGS. 12   c  and  12   d  which combine the features of the first and second embodiments. In this embodiment, the washer  56 ,  66  is applied to one or both sides of the clamping plate  52  to form an assembly  74 . The joining material  72  can be applied to one or both sides of the washer/clamping plate assembly  74  to seal this assembly  74  to the roof membrane  58  and the fastening member  54 . 
         [0042]    The fastening member  54  may be applied on site or, alternatively, the fastening member  54  may be formed as an integral component with the clamping plate/washer assemblies  57 ,  74 . Also, the fastening member  54  may be any well known type of fastener capable of exerting a clamping force against the washer or sealant material. Some examples of fastening members  54  include threaded fasteners, rivets, expansion bolts or interference fit fasteners that are driven into place. Some types of structural decks may require other specialty fasteners that also meet the clamping criteria. 
         [0043]    The use of the above fastening systems  50  and attachment methods used in combination with the roof membranes  58  result in a method that provides a redundant seal around the holes created in the roof membrane  58  by the fastening member  54 . This redundant seal, when used in combination with any of the known double seaming, disc or strip fastened systems, as discussed in detail with respect to  FIGS. 1-10 , prevents moisture or moisture laden air within the roof envelope of the fastening system  50 . The use of the inventive fastening system  50  also prevents any moisture which enters the seam channel as a result of a faulty outside seam or a puncture over the seam channel from entering the roof envelope. 
         [0044]      FIGS. 13-15  show various applications of the fastening system  50  of the present invention for mechanically securing a roof membrane  58  to a roof substrate  59  and roof decking  80 .  FIG. 13  shows an application of the invention for sealing a pair of overlapping roof membranes  58  wherein the fastening system  50  is positioned between edge portions  76 ,  77  of the overlapping roof membranes  58  and a double seam  78 ,  79  is formed on either side of the fastening system  50 . Air/moisture vapor  81  is trapped between the roof membrane  58  and the roof substrate  59 .  FIG. 14  shows an alternative application of the invention wherein an attachment disc  82  is positioned adjacent the roof substrate  59 , and a sealing device, which may be a washer  56  or joining material  72  is positioned on top of the attachment disc  82 , followed by clamping plate  52  and mechanically attached by fastening member  54 . The roof membrane  58  is placed over the fastening system  50  and double seamed at  78 ,  79  to the attachment disc  82 .  FIG. 15  shows yet another application of the invention utilizing a longitudinal cover strip  84  which overlays the fastening system  50  of the invention. The fastening system  50  secures the roof membrane  58  to the roof substrate  59  and roof decking  80 . The longitudinal strip  84  is then double seamed at  78 ,  79  to the roof membrane. 
         [0045]    The welded, frictional, or adhesive seal of the fastening system  50  to the underlying material of the present invention acts to improve the wind uplift resistance of the total roof system by preventing slipping and/or tearing of the roof membrane  58 . 
         [0046]    Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of this description. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.