Roofing flashings and roofing systems and photovoltaic roofing systems using the same

Abstract

The present invention relates more particularly to improved flashings for use in integrating specialized roof-mounted structures, such as photovoltaic devices for the generation of electrical energy, with conventional roofing materials on a roof. In one aspect, the invention provides a flashing element having a cross-sectional shape comprising a laterally-extending flange, the flange having an edge, a first end and a second end, the side flashing element comprising a return hem disposed at the edge and comprising a folded-over strip of material disposed over the top surface of the flange at the edge, the return hem having a first end disposed toward the first end of the edge, and a second end disposed toward the second end of the edge, wherein the total thickness of the return hem at its second end is no greater than the interior thickness of the return hem at its first end.

1 - 208 . (canceled) 
     
     
         209 . A roofing system comprising
 an underlying flashing element having a cross-sectional shape comprising a vertically-extending feature, a flange extending laterally from the vertically-extending feature at the downward end thereof, the flange having an edge opposing the vertically-extending feature, a first end and a second end, the underlying flashing element further comprising a vertical edgewall without a return feature, the vertical edgewall being disposed along the edge from the first end to the second end of the flange, wherein the total width of the flange at the second end thereof is no greater than the interior width of the flange at the first end thereof; and   an overlying flashing element having a cross-sectional shape comprising a vertically-extending feature, a flange extending laterally from the vertically-extending feature at the downward end thereof, the flange having an edge opposing the vertically-extending feature, a first end and a second end, the overlying flashing element further comprising a substantially vertical edgewall without a return feature, the vertical edgewall being disposed along the edge from the first end to the second end of the flange, wherein the total width of the flange at the second end thereof is no greater than the interior width of the flange at the first end thereof;   wherein
 the second end of the flange of the overlying flashing element overlaps the first end of the flange of the underlying flashing element, and 
 the vertical edgewall at the second end of the overlying flashing element nests within the vertical edgewall at the first end of the underlying flashing element. 
   
     
     
         210 . The roofing system according to  claim 209 , wherein each of the substantially vertical edgewalls is formed at an angle of about 90° with its corresponding flange. 
     
     
         211 . The roofing system according to  claim 210 , wherein each of the substantially vertical edgewalls has a height in the range of about 3 mm to about 10 mm. 
     
     
         212 . The roofing system according to  claim 209 , wherein each of the substantially vertical edgewalls has a height in the range of about 3 mm to about 10 mm. 
     
     
         213 . The roofing system according to  claim 209 , wherein each of the underlying flashing element and the overlying flashing element are formed from plastic. 
     
     
         214 . The roofing system according to  claim 209 , wherein each of the underlying flashing element and the overlying flashing element is configured as a side flashing element disposed on a roof deck with its first end as an up-roof end and its second end as a down-roof end. 
     
     
         215 . The roofing system according to  claim 209 , wherein each of the underlying flashing element and the overlying flashing element is configured as a top flashing element disposed substantially horizontally along a roof deck. 
     
     
         216 . The roofing system according to  claim 209 , wherein the each of the flanges of the underlying flashing element and the overlying flashing element is at least partially disposed between a roofing element and a roof deck. 
     
     
         217 . The roofing system according to  claim 209 , wherein the flange of the underlying flashing element has one or more mounting holes formed therein, and the flange of the overlying flashing element has one or more mounting holes formed therein. 
     
     
         218 . The roofing system according to  claim 209 , wherein the flange of the underlying flashing element has a width in the range of about 50 mm to about 500 mm, and the flange of the overlying flashing element has a width in the range of about 50 mm to about 500 mm. 
     
     
         219 . The roofing system according to  claim 209 , wherein the underlying flashing element nests with the overlying flashing element over an extending overlapping length of at least 35 mm. 
     
     
         220 . The roofing system according to  claim 209 , wherein, in each of the flashing elements, the interior width of the flange at the first end thereof is greater than the total width of the flange at the second end thereof by at least about 2 mm. 
     
     
         221 . A photovoltaic roofing system disposed on a roof deck having an up-roof end and a down-roof end, the photovoltaic roofing system comprising
 one or more photovoltaic roofing elements contiguously disposed on the roof deck, the contiguously-disposed roofing elements together having an up-roof edge facing the up-roof end of the roof deck, a down-roof edge facing the down-roof end of the roof deck, and two side edges;   a plurality of roofing elements disposed adjacent the contiguously-disposed photovoltaic roofing elements, along their side edges;   a roofing system according to claim  1 , disposed along the side edges of the contiguously-disposed photovoltaic roofing elements, with the flanges of the underlying flashing element and the overlying flashing element being at least partially disposed between a roofing element and the roof deck, and with vertically-extending features interacting with a lateral edge of the contiguously-disposed array of photovoltaic roofing elements to provide a water-resistant interface therebetween.   
     
     
         222 . The roofing system according to  claim 221 , wherein less than about 15 mm of the widths of the flange of each of the flashing elements remain exposed.