Patent Publication Number: US-7594369-B2

Title: System and method for waterproofing parapet walls

Description:
FIELD 
   The disclosure relates generally to a system and method for waterproofing parapet walls, and more particularly to a system and method for waterproofing parapet walls disposed on a roof. 
   BACKGROUND 
   Many roofs include parapet walls that extend a relatively short, upward distance from the top of the roof to which the walls are attached. These walls are provided on roofs for various reasons, including safety and aesthetics. Waterproofing parapet walls is obviously beneficial to the construction of the roofs from which parapet walls extend. Accordingly, a system and method for waterproofing these parapet walls would be desirable. 
   SUMMARY 
   Disclosed is a system for waterproofing interior surfaces of parapet walls disposed on a roof, wherein the parapet walls include an interior surface counter flashing and a surface cap. The system includes at least one waterproofing membrane configured to allow moisture to escape from a space between the at least one waterproofing membrane and the interior surfaces of the parapet walls, wherein the at least one waterproofing membrane is disposed to extend at least a portion of a distance along the interior surfaces from the surface cap to the roof from which the parapet walls extend. The system also includes a flap valve defined by the at least one waterproofing membrane, the flap valve being positioned between the surface cap and the roof. 
   Further disclosed is a method for waterproofing interior surfaces of parapet walls disposed on a roof, wherein the parapet walls include an interior surface counter flashing and a surface cap. The method includes disposing at least one waterproofing membrane to extend at least a portion of a way down the interior surfaces from the surface cap to the roof from which the parapet walls extend upwards, configuring the at least one waterproofing membrane to allow moisture to escape from a space between the at least one waterproofing membrane and the interior walls, providing a flap valve in the at least one waterproofing membrane, the flap valve being positioned between the surface cap and the roof, and removing the moisture from the space via the configuring and equalizing wind pressure on the at least one waterproofing membrane via the providing. 
   Still further disclosed are waterproof parapet walls disposed on a roof, the walls including interior surfaces disposed to face inwardly toward the roof, a counter flashing disposed on the interior surface, a surface cap disposed on an upper extent of the parapet walls, at least one waterproofing membrane disposed to extend at least a portion of a way down the interior surfaces from the surface cap to the roof from which the waterproof parapet walls extend upwards, wherein the at least one waterproofing membrane is configured to allow moisture to escape from a space between the at least one waterproofing membrane and the interior walls, and a flap valve defined by the at least one waterproofing membrane, the flap valve being positioned between the surface cap and the roof. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
     Referring to the drawings wherein like elements are numbered alike in the several Figures: 
       FIG. 1  is a schematic perspective view of a parapet wall and roof for use in a system for waterproofing interior surfaces of parapet walls; 
       FIG. 2  is a schematic perspective view of the parapet wall and roof of  FIG. 1 , wherein part of an exemplary embodiment of the system for waterproofing interior surfaces of parapet walls is shown; 
       FIG. 3  is a schematic perspective view of the parapet wall and roof of  FIG. 1 , wherein part of an exemplary embodiment of the system for waterproofing interior surfaces of parapet walls is shown; 
       FIG. 4  is a schematic perspective view of the parapet wall and roof of  FIG. 1 , wherein part of an exemplary embodiment of the system for waterproofing interior surfaces of parapet walls is shown; 
       FIG. 5  is a schematic perspective view of the parapet wall and roof of  FIG. 1 , wherein part of an exemplary embodiment of the system for waterproofing interior surfaces of parapet walls is shown; and 
       FIG. 6  is a schematic perspective view of the parapet wall and roof of  FIG. 1 , wherein an exemplary embodiment of the system for waterproofing interior surfaces of parapet walls is shown. 
   

   DETAILED DESCRIPTION 
   Referring to  FIGS. 1-6 , a system  10  for waterproofing interior surfaces  12  of parapet walls  14  disposed on a roof  16  is illustrated. The system  10  includes at least one waterproofing membrane that extends towards the roof  16  from a surface cap  20  of the wall  14  to cover at least a portion of the interior surface  12  of the wall  14 . In the exemplary embodiment of  FIGS. 1-6 , the at least one waterproofing membrane includes a skirt membrane  22 , a field membrane  24 , and a primary waterproofing membrane  26 . Association of these membranes with the roof  16  and parapet walls  14  will be discussed hereinbelow, beginning with specific reference to  FIG. 1 . 
     FIG. 1  illustrates a previously existing parapet wall  14  extending from the roof  16 , prior to application of any of the waterproofing membranes discussed above. As is shown in  FIG. 1 , the interior surface  12  of the parapet wall  14  includes a counter flashing  28 , which extends about a third of a way up the wall  14 . The counter flashing  28  may be strips of metal, roofing, or fabric anchored to a raglet (which is not illustrated, but may be formed within the walls  14 ) or attached to the interior surface  12  above the plane of the roof  16 . As shown in  FIG. 1 , the counter flashing  28  is turned down towards the roof  16 , so as to protect any base flashing and/or membrane already disposed on the wall  14  and/or roof  16  (i.e. flashing and/or membrane existing on the roof  16  and wall  14  prior to waterproofing membrane application). 
   Referring now to  FIGS. 2 and 3 , an adhesive layer  30 , such as atactic polypropylene (APP) or styrene-butadiene-styrene (SBS) mastic, is applied to roof  16  and walls  14 . As shown in  FIG. 2 , the adhesive layer  30  includes a horizontal portion  32  that is disposed over a portion of the roof  16  adjacent to the wall  14 , and a vertical portion  34  that covers some existing wall flashing  36  disposed below the counter flashing  28 . As shown in  FIG. 3 , a gravel mat  38  may be laid over the roof  16  and horizontal portion  32  of the adhesive layer  30 . If the gravel mat  38  and adhesive layer  30  are employed, the horizontal portion  32  of the adhesive layer  30  aids in affixing the mat  38  to the roof  16 . 
   Referring now to  FIG. 4 , the skirt membrane  22 , which includes a horizontal skirt portion  42  and vertical skirt portion  44 , is applied to portions of the roof  16  and wall  14 , respectively. The horizontal skirt portion  42  is disposed upon the gravel mat  38 , substantially parallel to the roof  16 . The vertical skirt portion  44  turns up interior surface  12  of the parapet wall  14  at a turn  46  between the roof  16  and wall  14 . The vertical skirt portion  44  is disposed in contact with the vertical portion  34  of the adhesive layer  30 , which helps attach the vertical skirt portion  44  to interior surface  12 . As shown in  FIG. 4 , the vertical skirt portion  44  is disposed substantially parallel to the interior surfaces  12 , and is positioned to extend from the roof  16  (i.e. the turn  46  between the roof  16  and wall  14 ) to a point at or beneath the lower extent  48  of the counter flashing  28 . The vertical skirt portion  44  may also be flashed to the interior surface  12  via skirt flashing  50 . 
   Referring now to  FIG. 5 , the field membrane  24 , which includes a horizontal field portion  54  and a vertical field portion  56 , is applied to the system  10 . The horizontal field portion  54  is upwardly disposed of the horizontal skirt portion  42  and gravel mat  38 , extending out (away from the wall  14 ) over the roof  16  past an extent  58  of the horizontal skirt portion  42  that is most distant from the wall  14 . A spacing structure  60 , such as seam tape, is disposed between the horizontal skirt portion  42  (at an area over the extent  58 ) and the horizontal field portion  54 . As shown in  FIG. 5 , the horizontal field portion  54  is disposed substantially parallel to the roof  16 . 
   The vertical field portion  56  is disposed substantially parallel to the interior surfaces  12  of the parapet walls  14 , extending from the turn  46  to a point at or beneath an upper extent  62  of the counter flashing  28 . The vertical field portion  56  is disposed in contact with the vertical skirt portion  44  and the portion of the counter flashing  28  that the vertical field portion  56  extends over. As shown in  FIG. 5 , the vertical field portion  56  may be adhered to both the vertical skirt portion  44  and counter flashing  28  (the adhering being represented at dashed line  64 ), and flashed to the counter flashing  28  via field flashing  66 . 
   Referring now to  FIG. 6 , a primary waterproofing membrane  26 , which includes a horizontal waterproofing portion  70  and a vertical waterproofing portion  72  is applied to the system  10 . The horizontal waterproofing portion  70  is affixed to the surface cap  20  via mechanical fastener  74  (though the portion  70  may also be adhered to the cap  20 ). At an interior edge  76  of the surface cap  20  the primary waterproofing membrane  26  turns down, and the vertical waterproofing portion  72  begins. The vertical waterproofing portion  72  extends substantially parallel to the interior surface  12  of the parapet wall  14 , covering a portion of the interior surface  12  that extends from the cap  20  to a point below the lower extent  48  of the counter flashing  28 . The portion of the vertical waterproofing portion  72  that extends past the lower extent  48  of the counter flashing  28  overlaps the vertical field portion  56 . 
   As shown in  FIG. 6 , a plurality of spacing structures are disposed between the vertical waterproofing portion  72  and the interior surface  12 , as well as between the relatively lower extent of the vertical waterproofing portion  72  and the vertical field portion  56 . In the exemplary embodiment of  FIG. 6 , the spacing structures between the vertical waterproofing portion  72  and the interior surface  12  are flash spacing structures  78 , and the spacing structures between the relatively lower extent of the vertical waterproofing portion  72  and the vertical field portion  56  are seam spacing structures  80  (such as seam tape). The flash spacing structures  78  may be disposed in alignment with flashing  82 , which affixes the vertical waterproofing portion  72  to the interior surface  12 . The flash spacing structures  78  create a space  84  between the vertical waterproofing portion  72  and the interior surface  12 . 
   The seam spacing structures  80  are non-continuous, and thus form a broken affixing seam  86  that affixes the vertical waterproofing portion  72  to vertical field portion  56 . The broken affixing seam  86  includes openings  88  that are configured to create open channels  90  between the vertical waterproofing portion  72  and the vertical field portion  56 . These channels  90  allow moisture  91  that accumulates, such as by condensation, in the space  84  between the vertical waterproofing portion  72  and the interior surface  12  to flow out of the space  84  to the horizontal field portion  54 . As such, these channels  90  effectively allow moisture  91  to weep out of the space  84 . 
   Also shown in  FIG. 6  is a flap valve  92  that is defined by the vertical waterproofing portion  72 . The flap valve  92  is essentially a smile shaped cut in the vertical waterproofing portion  72 , which is positioned between the surface cap  20  and roof  16 . The valve  92  is configured to equalize wind pressure, and thus may be further positioned in areas of high wind vortex activity in the system  10  in general. These areas may include the inside corners of parapet walls that at least partially surround the roof  16 . The valve  92  also provides moisture venting at these areas. Liquid moisture is prevented from entering the valve  92  via a cover membrane  94 , which is sealed to the vertical waterproofing portion  72  at an area relatively above and to the sides of the valve  92 . As shown in  FIG. 6 , the cover membrane  94  is not sealed at an area relatively below the valve  92 . This area provides an opening  96  that allows pressure under the roof  16  to escape, allowing the equalization of wind pressure discussed above. 
   While the invention has been described with reference to an exemplary embodiment, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or substance to the teachings of the invention without departing from the scope thereof. Therefore, it is important that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the apportioned claims. Moreover, unless specifically stated any use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.