Abstract:
Disclosed herein is an assembly that relates to a roof assembly comprising, at least one first waterproof membrane for covering a building roof and a stiff member sealed within at least one second waterproof membrane. The stiff member being substantially aligned with a perimeter of the building roof, and the first waterproof membrane being sealedly attached to the second waterproof membrane. The stiff member being attached to a structure of the building by a plurality of fasteners.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     Roofing systems of buildings with low pitch or flat roofs typically use waterproof membranes to prevent water from entering into the building. Large sheets of such membranes are welded or glued to one another, depending on the material of the membrane, to form continuous sheets that cover the entire surface of the roof.  
         [0002]     Membranes require termination of one kind or another at least at a perimeter edge of the roof. Because the perimeter edge of the roof is an area that experiences forces that act in different directions as well as being an area where wind vortices create low pressure regions, the roof is prone to expansion and contraction as well as wind failure in this area. Parapet walls and sheet metal gutters, gravel stops and fascia finishes can leak in this area damaging conventional perimeter membrane terminations. Typical edge termination practices such as; nailers, termination bars, reinforced membrane strips and fasteners are prone to failure for mainly two reasons: first, the pulling of the membrane due to high winds eventually tears the membrane at the stress concentration points created by the small discrete or non-uniform areas of membrane retention; and second, moisture finds its way to the boards in which the retaining features are embedded, causing rotting that eventually results in the fasteners coming loose from the boards. Once the membrane is no longer retained at the perimeter of the roof, winds can easily peal it away allowing water from rain and snow to enter the building through the unprotected roof.  
         [0003]     Accordingly, there is a need in the art for improvements in retention of waterproof roof membranes, particularly at the perimeter of a roof.  
       BRIEF DESCRIPTION OF THE INVENTION  
       [0004]     Disclosed herein is an assembly that relates to a roof assembly comprising, at least one first waterproof membrane for covering a building roof, a stiff member sealed within at least one second waterproof membrane, the stiff member being substantially aligned with a perimeter of the building roof, and the first waterproof membrane being sealedly attached to the second waterproof membrane. The stiff member being attached to a structure of the building by a plurality of fasteners.  
         [0005]     Further disclosed is a system that relates to a hurricane resistant roof perimeter waterproofing system comprising, at least one first waterproofing membrane and at least one second waterproofing membrane being sealed to the at least one first waterproofing membrane. A plurality of stiff members encapsulated by the at least one first waterproofing membrane or the at least one second waterproofing membrane, and a plurality of fasteners that attach the stiff member to a structure of a building.  
         [0006]     Further disclosed herein is a method that relates to terminating an edge of a roof waterproofing membrane comprising, covering a building roof with at least one first waterproofing membrane, aligning at least one stiff member along a perimeter of the building roof, and covering the at least one stiff member within a second waterproofing membrane. Further, sealing the second waterproofing membrane to the first waterproofing membrane, and attaching the stiff member to the structure of the building. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:  
         [0008]      FIG. 1  is a cross sectional view of a prior art single ply membrane roof assembly system;  
         [0009]      FIGS. 2A and 2B  are cross sectional views of a single ply membrane roof assembly system of an embodiment of the present invention used as an original new construction roof in a vertical application;  
         [0010]      FIGS. 3A and 3B  are cross sectional views of a roof assembly system of an embodiment of the present invention used in a re-roofing application in a horizontal application;  
         [0011]      FIG. 4  is a cross sectional view of a roof assembly system of an embodiment of the present invention used on a roof with a parapet wall;  
         [0012]      FIG. 5  is a cross sectional view of a roof assembly of an embodiment of the present invention used in a re-roof application over a built up roof assembly;  
         [0013]      FIG. 6  is a cross sectional view of a roof assembly of an embodiment of the present invention for a roof deck on which fastener penetrations are not desirable;  
         [0014]      FIG. 7  is a cross sectional view of a roof assembly of an embodiment of the present invention used in a re-roof application similar to that of  FIG. 3 ;  
         [0015]      FIG. 8  is a cross sectional view of a roof assembly of an embodiment of the present invention used in a re-roof application similar to  FIG. 4 ;  
         [0016]      FIG. 9  is a cross sectional view of an alternate embodiment of the invention with an encapsulated stiff member and a piece of rigid roof insulation;  
         [0017]      FIG. 10  is a cross sectional view of an alternate embodiment of the present invention of an encapsulated stiff member made of extruded aluminum;  
         [0018]      FIG. 11  is a cross sectional view of another embodiment of the present invention of an encapsulated stiff member synthetic board; and  
         [0019]      FIG. 12  is a yet another cross sectional view of another embodiment of the invention of an encapsulated stiff member. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]     Referring first to  FIG. 1 , a prior art single ply membrane roof assembly system is generally shown at  10 . The structural building wall  12  supports one end of a structural roof beam  14 , which for purposes of this disclosure also includes such structural roof members as rafters and joists as well as metal, concrete or the like roof deck panels  16  that are fastened to the structural roof beam  14 . Insulation layer  22  is installed or fastened to the roof deck panels  16  by fasteners  18 . A field membrane  24  is installed onto insulation layer  22  by means of an adhesive  26 . The membrane  24  may be made of ethylene propylene diene monomer (EPDM), chlorosulfonated polyethylene (CSPE), polyvinyl chloride (PVC) or similar roof waterproofing single ply membranes. To complete the installation, wood blocking often referred to as a nailer  28  is used at the perimeter edge of the building  20  anchored to the building wall  12  by fasteners  30  and capped by gravel stop metal edging  32  over which flashing  36  is installed.  
         [0021]     Referring to  FIG. 2A , an embodiment of the present invention used as an original roof is generally shown at  50 , which is a partial cross sectional view, that parallels  FIG. 1 . Structural building wall  12  supports one end of structural roof beam, rafter or joist  14 . Metal, concrete or the like roof deck panels  16  are fastened to the structured roof beam  14 . The roof insulation panel layer  22  is installed or fastened to the roof deck panels  16  by fasteners  18 .  
         [0022]     A waterproof field membrane  44  is installed onto roof insulation layer  22  by means of adhesive  26 . The membrane  44  extends beyond the wall  12  far enough to have a wrap portion  46  of the membrane  44  back wrap around a stiff member  40  and allow an interior edge  48  to lay back upon a membrane portion  41  of the membrane  44 . The interior edge  48  is attached to the membrane portion  41  thereby encapsulating the stiff member  40  within the waterproof membrane  44 . The membrane  44  can be attached to itself or another membrane in a number of ways such as solvent welding, heat welding, contact adhesive gluing, or double sided adhesive taping, for example, hereafter referred to as welded or glued  49 . The method chosen is the one most suitable for the roof waterproofing membrane chosen. The stiff member  40  is attached to the wrap membrane portion  46  with adhesive  26 . Fasteners  42  shown here as nails may also be screws or other elongated retention devices that penetrate the building or roof decking structure, thereby providing a more robust anchoring of the membrane perimeter than is achieved by fastening to a nailer  38  alone. The fasteners  42  in this embodiment attach the encapsulated stiff member  40 , which lies flush with a surface of the wall  12 , to the building structure of the wall  12 . The stiff member  40  lies on a side of the wall  12  opposite a side of the wall  12  in which the roof is positioned. Adhesive  26  is applied between the wrap membrane portion  46  and the wall  12  to prevent moisture ingress at that location and to provide added structural retention of the stiff member  40  and membrane portion  46  to the wall  12 .  
         [0023]     By sandwiching the membrane portion  46  between the stiff member  40  and the wall  12  the membrane portion  46  is retained uniformly along the length of the wall  12 . This uniformity prevents the formation of any local stress risers, which could exceed the strength of the membrane material, resulting in tearing when the membrane portion  46  is pulled as occurs when wind blows up the side and over the roof creating a lower pressure on the upper surface of the membrane  44 . Additionally, by being sealed in a waterproof envelope created by the encapsulating membrane portion  46  the stiff member  40  will remain dry; preventing it from rotting. Rotting of perimeter nailers  38  is problematic in that it allows fasteners, that are holding a membrane in place, to break free thereby increasing the load on the remaining fasteners, which results in tearing of the membrane, which can then be easily pealed back exposing the non-waterproof roof components to rain and snow.  
         [0024]     In some embodiments of the invention the stiff member  40  may be made of any stiff material including plywood, oriented strand board (OSB), treated lumber, synthetic plastic sheeting, and metal, for example, although non-grained materials have an advantage of resisting splitting. Additionally the stiff member  40  has properties of stiffness such that it holds its shape even while being pulled nonuniformly by attachments to roof and building structures and membranes for example. By holding its shape the stiff member  40  distributes any loads applied to it over the entire body of the stiff member  40  thereby minimizing localized stress levels. Dimensions of six to ten inches in a substantially vertical direction and two to four feet in a substantially horizontal direction are therefore in accordance with the invention however the invention is not limited to these dimensions.  
         [0025]     Referring to  FIG. 3A , an embodiment of the present invention used as a replacement roof is generally shown at  60 . As discussed relative to the prior art roof system, structural building wall  12  supports one end of structural roof beam, rafter or joist  14 . Metal, concrete or the like roof deck panels  16  are fastened to the structured roof beam  14 . Insulation panel layer  22  is installed or fastened to the roof deck panels  16  by fasteners  18 .  
         [0026]     In accordance with an embodiment of the invention, a new membrane referred to as a re-roof membrane  64  is applied over the original roof&#39;s field membrane  44 . A separation member  62  (or matting-fleece  78  as shown in  FIG. 4 ) is placed over the original roof&#39;s field membrane  44  and gravel  34  to protect the re-roof field membrane  64  from damage from below. The separation member  62  is fastened through the insulation  22  and into the roof panels  16  by fasteners  63 . Blocking (nailer)  69  is added around the perimeter of the roof  20  to form a level area with the surface of the separation member  62 . The re-roof membrane  64  extends beyond the wall  12  and forms a wrap portion  66  of the re-roof membrane  64  that folds over a stiff member  40  and back onto itself at an interior edge  68 . The interior edge  68  is welded or glued  49  to the re-roof membrane  64  to form a waterproof encapsulation around the stiff member  40 . Adhesive  26  attaches the stiff member  40  with the wrap portion  66  of the membrane  64 . Fasteners  42  attach the stiff member  40  and membranes  66 ,  64  to the building structure of the wall  12  and the roof panels  16 . It should be noted that throughout this disclosure the structural members of the building may include any of the following: the wall  12 , roof beam  14  and roof panels  16  as described above as well as other embodiments of these structures as described below. Additionally, building members that are not described herein but may serve as a structural portion of the building, for purposes of attaching the stiff member  40  thereto, will also be encompassed by the spirit and scope of embodiments of the present invention.  
         [0027]     Sealing the stiff member  40  in an encapsulation of membrane material without protrusions therethrough is desirable to minimize water intrusion. However, certain aspects of a roofing structure may make it difficult or impossible. A comparison of  FIGS. 2A and 2B  effectively illustrate this point. In  FIG. 2A  the fasteners  42  may be driven through the stiff member  40  prior to welding or gluing  49  the wrap portion  46  to the field membrane  44  thereby permitting fasteners heads  45  to be sealed within the encapsulation. In contrast, in  FIG. 2B  the stiff member  40  is encapsulated and sealed within a membrane  47  prior to the membrane  47  being welded or glued  49  to the field membrane  44  making it impossible to then apply fasteners  42  without forming holes  43  through the membrane  47 . Both methods, however, with the fastener heads  45  within the encapsulation and with fastener heads  42  outside of the encapsulation are within the scope of the invention and may be applied to any embodiments of the invention. Referring to  FIG. 4 , an embodiment of the present invention applied to a building having a parapet wall is generally shown at  70 . As discussed relative to the prior art roof system, structural building wall  12  supports one end of structural roof beam, rafter or joist  14 . Metal, concrete or the like roof deck panels  16  are fastened to the structured roof beam  14 . Roof insulation panel layer  22  is installed or fastened to the roof deck panels  16  by fasteners  18 .  
         [0028]     In  FIG. 4  wall  12  is a parapet wall  72  that extends in elevation above where the roof deck meets the parapet wall  72 . A new membrane referred to as a re-roof field membrane  74  is applied over the original roof&#39;s field membrane  44 . A layer of matting-fleece  78  (or a separation member  62  as shown in  FIG. 3A ) is placed over the original roof&#39;s field membrane  44  and gravel  34  to protect the re-roof field membrane  74  from damage from below. The re-roof membrane  74  extends beyond the interface between the roof and the parapet wall  72  and folds upward at the interface leaving a protruded re-roof membrane portion  73  that is adhered to the parapet wall  72  with adhesive  26 . A stiff member  40  is positioned on top of the re-roof membrane  74  adjacent to the parapet wall  72  such that the protruded re-roof membrane portion  73  is sandwiched between an edge of the stiff member  40  and the parapet wall  72 .  
         [0029]     A separate piece of membrane material referred to as flashing  75  is draped over the top of the parapet wall  72  and down over the protruded re-roof membrane portion  73 , the stiff member  40  and the re-roof membrane  74 . The flashing  75  is attached to the stiff member  40  with adhesive  26  and is either welded or glued  49  to the protruded re-roof membrane portion  73  and the re-roof membrane  74  to encapsulate the stiff member  40  inside a waterproof pocket of membrane material. The portion of the flashing  75 , which is draped over the parapet wall  72 , is attached to the parapet wall  72  with adhesive  26  forming a continuous watertight seal from the outer surface of the parapet wall  72  to the re-roof membrane  74 . Fasteners  42  secure the stiff member  40 , the membrane  73  and the insulation  22  to the structural roof deck panels  16 .  
         [0030]     Durability of the membranes to weather conditions is also an item of concern. In order to make the membrane more durable to such conditions some thermoplastic membrane materials are treated with ultraviolet (UV) stabilizers and anti-fungicides, for example. Due to cost reasons such treatments are commonly performed on only one side of the membrane materials, hereafter referred to as the weatherproof side  76 , it is sometimes desirable to install membranes with this weatherproof side  76  on the outside. In embodiments of  FIGS. 2A and 3A  the portions of the thermoplastic membrane  46 ,  66 , which are covering the stiff member  40 , and are exposed to the atmosphere are not the weatherproof side  76  of the membranes  46 ,  66 . Since the membranes  44 ,  64  in these embodiments are one continuous sheet of membrane covering the roof and encapsulating the stiff member  40 , then either the portion covering the roof or the portion encapsulating the stiff member  40  must be the side opposite the weatherproof side  76 . Embodiments shown in  FIGS. 2B and 3B  overcome this problem by splicing a reversed layer  47 ,  67  of the membrane to the perimeter edge of the field membrane  44 ,  64  such that the weatherproof side  76 , of the reversed membrane  47 ,  67  covering the stiff member  40 , is exposed to the atmosphere. Since the embodiment of already uses a separate piece of membrane, namely the flashing  75 , to cover the stiff member addressing the issue of having the weatherproof side  76  facing outward is simply accomplished by orienting it in this matter prior to applying it.  
         [0031]     Referring to  FIG. 5 , another re-roofing embodiment of the present invention is generally shown as roof assembly  80 . As in  FIG. 4 , the membrane of  FIG. 5  is applied over an existing roof assembly. This roof assembly  80  is of a re-roof membrane  74  applied over a built-up-roof (BUR)  82 . The re-roof membrane  74  partially wraps around stiff member  40  near the perimeter of the roof  20 . The flashing  75 , with the weatherproof layer  76  such as an ultraviolet (UV) protection layer for example, facing the atmosphere, covers the remainder of the stiff member  40  and is welded or glued  49  to the re-roof membrane  74  at either end of the stiff member  40 . Thus forming a waterproof encapsulation around the stiff member  40 . Fasteners  42  attach the stiff member  40  and membrane  74  to the structural layers, specifically through a lightweight concrete layer  84  and into a pour-in-place concrete deck layer  88 . The embodiment illustrated in  FIG. 5  also shows the present invention applied to a sloped roof assembly  80 .  
         [0032]     A seal  85  placed between the membrane  74  encapsulating the stiff member  40  and the lightweight concrete  84  prevents the ingress of air and water at that location. Butyl gum or other air and water sealing methods may be employed as seal  85 .  
         [0033]     Referring to  FIG. 6 , a roof assembly  90  is shown using decking materials  92  that cannot be easily fastened into with typical mechanical fasteners  42 . An air seal membrane  91  is applied under the perimeter edge of the insulation  22  and bonded to the structural roof deck material  92  and an abutting wall  93  with adhesive  26 . Reversed membrane  95  is wrapped around stiff member  140  and is welded or glued  49  to itself forming an uninterrupted membrane barrier encapsulating the stiff member  140 . Fasteners  42  attach the encapsulated stiff member  140 , to the structurally sound wall  93 , thereby negating the need to fasten into the deck  92 . Sandwiched between the wall  93  and the encapsulated stiff member  140  is the air seal membrane  91  and butyl gum type seal  85 . The reversed membrane  95  is welded or glued  49  to the field membrane  94 . The membranes  94  and  95  depicted here are made of a fiber reinforced  96  PVC thermoplastic.  
         [0034]     An angled cut  142  along an edge of the stiff member creates a channel  144  between the wall  93  and the angled cut  142 . The channel  144  retains caulking  146  to seal the reversed membrane  95  to the wall  93 . In addition, the corners  148  of the stiff member  140  are rounded-off to reduce stress and the potential for tearing of the membrane  95  that could result from a sharp corner.  
         [0035]     Referring to  FIG. 7 , an alternate embodiment of the present invention shown in  FIG. 3A  is generally shown at  110 . Wherein, in  FIG. 3A  the re-roofing membrane  64  ended at the existing edge of the roof assembly  60 , in  FIG. 7 a  flashing membrane  106  extends over the edge covering the gravel stop  32 , thereby preventing the ingress of water between the membrane  106  and the gravel stop  32 . Adhesive  26  attaches the membrane  106  to the gravel stop  32  and fasteners  109  attach bracket  108 , membrane  106  and gravel stop  32  to the blocking  69 . In addition to covering the gravel stop  32  the flashing membrane  106  is welded or glued  49  to the re-roof membrane  104  in two locations to form a waterproof encapsulation around the stiff member  40 . Stated another way, the re-roof membrane  64  is extended beyond the perimeter of the roof  20  and terminated by mechanically fastening a stiff member  40  over the membrane  64  and into the roof deck  16 . The extension of the membrane  64  beyond the perimeter edge is back wrapped over the stiff member  40  and welded or glued  49  to the flashing membrane  106  to encapsulate the stiff member  40 . Referring to  FIG. 8 , an alternate embodiment of the present invention is generally shown at  120 . The field membrane  124  continues from the surface of the roof up the side of the abutting wall  93 , where it is sealed and glued with adhesive  26  to the wall  93 . A separate piece of membrane  126  is welded or glued  49  to the field membrane  124  on both sides of the stiff member  40  creating a waterproof encapsulation around the stiff member  40 . A seal  85  is formed between the existing roof surface  128  and the lower surface of the membrane  126  to create a watertight seal and prevent ingress of water or air at that location.  
         [0036]     Referring to  FIG. 9 , an alternate embodiment of the invention is generally shown at  125 . The field membrane  124  near the roof perimeter  20  is welded or glued  49  to two other membranes  126  and  127 . Membrane  126  extends below the stiff member  40  that is structurally attached to the precast hollow core concrete  129  of the existing roof with fasteners  42 . A seal  85  located below the stiff member  40  and between the membrane  126  and the existing roof forms a seal to prevent ingress of air and water. The membrane  126  continues up the abutting wall  93  with one side being attached to the wall  93  with adhesive  26  and the other side being welded or glued  49  to the upper membrane  127  thereby forming an encapsulation of the stiff member with the three membranes  124 ,  126  and  127 . An insulation layer  122  is positioned above and fastened to the stiff member  40  with fasteners  42  and is contained within the encapsulation formed by the three membranes  124 ,  126  and  127  with the stiff member  40 . The upper membrane  127 , in addition to being welded or glued  49  to the membranes  124  and  126 , is attached to both the wall  93  and to the insulation layer  122  with adhesive  26 .  
         [0037]     Referring to  FIG. 10 , an alternate embodiment of an encapsulated stiff member assembly  130  is shown. Encapsulated stiff member  132  is an extruded metal or synthetic plastic sheet with generous radii on edges  136  to reduce stress and prevent tearing of the membrane  134 . The membrane  134  is double wrapped around the stiff member  132  at corner  138  where the highest stresses are expected due to wind creating a low pressure cell and lifting the membrane  134 . Thus two layers of membrane  134  are provided at corner  138  of stiff member  132  to provide additional tear resistance of the membrane  134 . In areas where the membrane is overlapping itself due to the double wrapping it is welded or glued  49  to itself. Adhesive  26  attaches the membrane  134  to the stiff member  132  to prevent the membrane  134  from moving relative to the stiff member  132 .  
         [0038]     Referring to  FIG. 11 , an alternate embodiment of an encapsulated stiff member assembly  150  is shown. A piece of field membrane  152  is glued around a corner  158  of stiff member  40  with adhesive  26 . A field membrane  154  wrapped around and glued to stiff member  40  with adhesive  26  and is welded or glued  49  to itself encapsulating the stiff member  40  within a waterproof encasing of membrane  154 . Additionally, the membrane  154  is welded or glued  49  to the field membrane  152  thereby creating a double membrane layer over corner  158 . The additional layer of field membrane  152  creates a cushion for the field membrane  154  and thereby distributes any load due to wind lifting the membrane  154  over a wider area. The adhesive  26  attachments of the membranes  154 , and  152  to each other and to the stiff member  40  prevent relative movement between the stiff member  40  and membranes  152 ,  154  thereby preventing abrasion. Embodiments of the invention may use the stiff member encapsulations of  FIGS. 10 and 11  alone or in addition to the embodiments of the invention with a field water proofing membrane.  
         [0039]     Referring to  FIG. 12 , an embodiment of a universal perimeter edge  160  is shown. A piece of membrane  162  is wrapped around the stiff member  40  and welded or glued  49  to it self thereby encapsulating the stiff member  40  in an air and watertight enclosure. The stiff member  40  is attached to the membrane  162  by adhesive  26  to prevent relative movement between the two components. This universal perimeter edge  162  can be applied to other embodiments of the invention such as that depicted in  FIG. 2B  for example.  
         [0040]     While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.