A ribbed roof T-joint or butt joint patch is provided for application to intersecting and overlapping portions of a single ply membrane of different heights. When applied to the joint formed by the intersecting and overlapping membranes, the ribbed joint patch having an adhesive layer conforms to the void formed by the joint and assures a water tight seal. A method of making a roof joint patch and a method of applying a ribbed joint patch to a void formed by intersecting and overlapping membranes are also disclosed.

FIELD OF THE INVENTION  
       [0001]     The present invention relates to roofing materials. More specifically, the present invention is directed to a patch to fill voids created by overlapping roofing membranes.  
       BACKGROUND OF THE INVENTION  
       [0002]     Single ply membranes are roofing membranes that are field applied using just one layer of membrane material (either homogeneous or composite) rather than multiple layers. Oftentimes as a result of the overlapping intersection of two, three or four sheets of the membrane, a joint is created.  
         [0003]     Current joint patches are flat membranes with the butyl or similar adhesive applied to one side with a release liner. Often, when applied to intersecting and overlapping portions of a single ply membrane of different heights, the adhesive does not conform to the vertical step in height thus causing bridging and leaving a void into which water and debris can enter.  
       SUMMARY OF THE INVENTION  
       [0004]     When roofing membranes intersect or overlap with one another, joints may be formed at the points of intersection or overlap. A T-joint is a joint formed by the intersection or overlapping of three or four membrane sheets. A butt-joint is a joint formed by adjacent, separate sections of material, such as where two neighboring pieces of roofing membrane abut. The joints formed by the intersection and/or overlapping of roofing membranes can be problematic since the void formed by the joint permits water to seepage into and underneath the roofing membranes.  
         [0005]     A joint patch is provided to alleviate the problem inherent in the formation of “joints” formed as a result of the overlapping intersection of sheets in the roofing membrane. In one embodiment, the T-joint patch is ribbed and may be circular, oval, square or rectangle. The patch is comprised of a single ply roofing membrane preferably ranging in size from approximately 3 inches to 9 inches. Examples of single ply roofing membranes from which the patch is formed includes, but is not limited to, thermoplastic olefin (TPO), polyvinyl chloride (PVC), ethylene propylene diene terpolymer (EPDM) or chlorosulfonated polyethylene (Hypalon®).  
         [0006]     The joint patch can be injection molded or fabricated by other conventionally known methods, with a rib or similar design having an approximate height of 20-90 mils on the flat plane of the membrane that will receive a butyl or other type of adhesive compound and a release liner. This design will allow for the adhesive to fill in the void created by the overlapping membranes thus assuring a tight seal. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0007]      FIG. 1  depicts overlapping membranes forming a T-joint or void;  
         [0008]      FIG. 2  is a perspective view of a circular T-joint patch in accordance with one embodiment of the present invention;  
         [0009]      FIG. 3  illustrates a top view of the T-joint patch of  FIG. 2  secured in the T-joint formed by the overlapping membranes;  
         [0010]      FIG. 4  illustrates another top view of the T-joint patch of  FIG. 2  secured in the T-joint formed by the overlapping membranes;  
         [0011]      FIG. 5  illustrates a view of the roof side of a joint patch having two ribs which segment the patch into four quadrants;  
         [0012]      FIG. 6  illustrates a top view of the a joint patch in which a single rib, segmenting the patch into halves, is seen in skeletal view;  
         [0013]      FIG. 7  illustrates a top view of the joint patch of  FIG. 6  secured in the joint formed by the overlapping membranes;  
         [0014]      FIG. 8  illustrates a top view of a butt-joint patch secured in the joint formed by the overlapping membranes. 
     
    
     DETAILED DESCRIPTION  
       [0015]     In  FIG. 1 , a joint, commonly referred to as a T-joint, (indicated by the circle denoted X) is formed by the intersection of three (3) membranes  100   a,    100   b,    100   c.  A first embodiment of the T-joint patch  10  is illustrated in  FIG. 2 . Patch  10  in one embodiment is circular or oval. Patch  10  is planar and has a first side  12  (roof side) and a second side  14  (weather side). A T-shaped rib  16  is positioned on first side  12 . T-shaped rib  16  divides first side  12  of patch  10  into three sections. A layer of adhesive  18  such as a butyl layer or other similar waterproofing adhesive layer, is then coated on T-shaped  16  and first side  12  of patch  10 . A release liner  20  is then positioned on first side  12  of patch  10  and conforms to the shape of patch  10 . Patch  10  is not limited to a circular or oval shape and may also be square or rectangular.  
         [0016]     In use, release liner  20  is peeled or removed from first side  12  of patch  10 . The T-shaped rib  16  is then positioned to conform with the T-joint formed by the intersection of membranes  100   a,    100   b,    100   c  and is fitted in the T-joint. Adhesive layer  18  on first side  12  of patch  10  secures side  12  of patch  10  to membranes  100   a,    100   b,    100   c.  To provide a water-tight seal, pressure is usually applied to second side  14  of patch  10 . Pressure may be applied by any known means, including the use of a roller or by applying pressure using one's hands. Heat may also be applied to second side  14  of patch  10  to provide a heat seal.  FIGS. 3 and 4  illustrate patch  10  applied on membranes  100   a,    100   b,    100   c.  T-shaped rib is positioned in T-shaped joint (not visible), and adhesive layer  12  secures first side  12  of patch  10  to membranes  100   a,    100   b,    100   c,  leaving second side  14  as the exposed surface.  
         [0017]     T-joint patch  10 , in one embodiment, is a single ply roofing membrane ranging in size from approximately 3 inches to 9 inches, but the size and shape of the patch is not limited in this respect. Examples of single ply roofing membranes from which patch  10  is formed include thermoplastic olefin (TPO), polyvinyl chloride (PVC), ethylene propylene diene terpolymer (EPDM) or chlorosulfonated polyethylene (Hypalon®). The T-joint patch can be vacuum or injection molded, or fabricated by other conventionally known methods, with a T-shaped rib having an approximate height of 20-90 mils on the flat plane of the membrane that will receive a butyl or other type of adhesive compound and a release liner.  
         [0018]     In a second embodiment illustrated in  FIG. 5 , joint patch  10  is vacuum or injection molded and segmented (or divided) into four quadrants by intersecting ribs  16 ,  16   b.  Each quadrant formed by the intersection of ribs  16   a,    16   b  have a different height and having the same thickness of butyl or other adhesive layer thereon, along with a release liner (not shown).  
         [0019]     In a third embodiment, joint patch is segmented into four quadrants as in  FIG. 5 . In this embodiment, the four quadrants formed by intersecting ribs, combined with the butyl layer (or other adhesive layer), and the release liner, all have a different thickness. The difference in the thickness of the quadrants is to accommodate the differences in height of intersecting roofing membranes, which are oftentimes placed on top of one another such that one or more sides of a of a joint may be higher than other sides.  
         [0020]     In another embodiment illustrated in  FIG. 6 , a joint patch  10  is segmented into two sections  20   a,    20   b  by a single rib  16 . Sections  20   a  and  20   b  may or may not be equal halves. Each of sections  20   a,    20   b  are provided with a butyl layer or other adhesive layer, and a release liner. Furthermore, each of sections  20   a,    20   b  has a different thickness.  FIG. 7  illustrates joint patch  10  of  FIG. 6  applied on membranes  100   a,    100   b,    100   c  in a horizontal joint  22 .  
         [0021]     In another embodiment in accordance with the present invention, patch  10  may be used for sealing a butt joint formed by adjacent, separate sections of material, such as roofing membrane sheets. A butt joint patch generally has a single rib on the deck side of the patch and extending from one side of the patch to the other side, much like patch  10  illustrated in  FIGS. 6 and 7 . The single rib on the deck side of the patch generally splits butt joint patch into two equal sections, however the invention is not limited in this respect, and rib may divide butt joint patch into unequal sections. As with the other joint patches described herein, the butt joint patch will also be provided on its deck side with a butyl layer or other adhesive layer, and a release liner on the butyl or other adhesive layer. The butt joint patch in accordance with the present invention can be vacuum molded, injection molded or fabricated by other conventionally known methods.  
         [0022]      FIG. 8 , illustrates butt joint patch  10  having a single rib  16  on its deck side positioned in a butt joint  24  formed by the intersection/overlapping of membrane  100   a  and  100   b.    
         [0023]     In still another embodiment there is provided a butt joint patch having a vacuum or injection molded membrane having a single rib  16  which segments the membrane into two sections of two different heights, each segment having the same thickness of butyl or other adhesive layer thereon, along with a release liner.