Multi-layer shingle with shiplap joint

Abstract

A multi-layer laminate shingle has a base layer and at least a second layer above the base layer. At one end of the shingle the base layer projects beyond the second layer while at the other end the second layer projects beyond the base layer. When the shingles are laid in a course along the roof, the projecting end of the second layer overlaps the projecting end of the base layer of the next shingle, forming a shiplap joint over all or substantially all of the width of the shingle, protecting the joint against rain penetration. This shiplap feature allows the headlap to exposure ratio of the shingle to be reduced to less than 1 and even to 0.5 or less, thus reducing the cost of shingles per unit of roof coverage area. If desired, a narrow strip can be adhered to the top of the headlap portion of the shingle or beneath the butt portion of the shingle to emulate the appearance of a costly triple laminate shingle.

1 . A roofing shingle comprising: 
 a) a base layer having first and second longitudinally spaced-apart end edges defining between them a length for said base layer, said base layer also having laterally spaced-apart top and bottom edges defining a width for said base layer, said base layer having an upper surface,    b) a second layer laminated to said upper surface of said base layer,    c) said second layer having a first end portion inset from said first end edge of said base layer over at least a substantial portion of the width of said base layer, said first end portion being inset from said first end edge from a position adjacent said top edge of said base layer to a position at or near said bottom edge of said base layer, so that said first end edge of said base layer extends in a longitudinal direction beyond said first end portion of said second layer over said substantial portion of the width of the base layer to form a projecting end of said base layer,    d) said second layer having a second end portion extending longitudinally beyond said second end edge of said base layer over at least a substantial portion of the width of said base layer, said second end portion so extending from a position adjacent said top edge of said base layer to a position at or near said bottom edge of said base layer to form a projecting end of said second layer,    e) so that when two or more of said shingles are assembled end to end to form a horizontal course of shingles, said projecting end of said second layer of one shingle will extend over the projecting end of said base layer of an adjacent shingle to form a shiplap joint, whereby to protect the joint between adjacent shingles from penetration by rain.    
     
     
         2 . A roofing shingle according to  claim 1  and having a headlap area adapted to be covered by the next higher course of shingles, and an exposed area adapted to be visible on a roof, and wherein the ratio of said headlap area to said exposed area is less than or equal to 1.  
     
     
         3 . A roofing shingle according to  claim 2  wherein said ratio is less than 1.  
     
     
         4 . A roofing shingle according to  claim 3  wherein said ratio is less than 0.5.  
     
     
         5 . A roofing shingle according to  claim 3  wherein the length of said projecting end of said base layer and the length of said projecting end of said second layer are substantially the same.  
     
     
         6 . A roofing shingle according to  claim 5  wherein said length of said projecting portions is between 2 inches and 6 inches.  
     
     
         7 . A roofing shingle according to  claim 1  wherein said second layer comprises a plurality of separate portions.  
     
     
         8 . A roofing shingle according to  claim 1  wherein said second layer comprises a single sheet having cutouts therein to form tabs.  
     
     
         9 . A roofing shingle according to  claim 1  and including a third sheet laminated on top of a portion of said second layer.  
     
     
         10 . A roofing shingle according to  claim 1  and including a third sheet laminated beneath said base layer.  
     
     
         11 . A plurality of roofing shingles each in accordance with  claim 1 , said roofing shingles being assembled end-to-end to form a horizontal course of shingles with vertical joints between them, at least a substantial portion of said vertical joint between each adjacent pair of shingles being covered by a said projecting end of said second layer of one of said shingles.