Slip-resistant roofing felt

Abstract

A roofing underlayment includes a flexible sheet made of felt at least partially impregnated with a coating material. The sheet is provided with at least one ridge extending in a substantially longitudinal direction. The ridge projects upwardly from the sheet and is flexible such that the ridge is collapsible when a downward force is applied thereto. The ridge is defined by a portion of the sheet. A method for making the roof underlayment is also disclosed.

1 . A roofing underlayment, comprising a flexible sheet made of felt at least partially impregnated with a coating material, said sheet including at least one ridge extending in a substantially longitudinal direction, said at least one ridge projecting upwardly from said sheet and being flexible such that said at least one ridge is collapsible when a downward force is applied thereto. 
     
     
         2 . The roofing underlayment of  claim 1 , wherein said at least one ridge is defined by a portion of said sheet. 
     
     
         3 . The roofing underlayment of  claim 2 , wherein said at least one ridge is made of said felt. 
     
     
         4 . The roofing underlayment of  claim 3 , wherein said at least one ridge includes a plurality of ridges, each of which is defined by a portion of said sheet. 
     
     
         5 . The roofing underlayment of  claim 4 , wherein each of said plurality of ridges is substantially linear. 
     
     
         6 . The roofing underlayment of  claim 5 , wherein each of said plurality of ridges has a substantially U-shaped profile. 
     
     
         7 . The roofing underlayment of  claim 5 , wherein each of said plurality of ridges has a substantially triangular profile. 
     
     
         8 . The roofing underlayment of  claim 5 , wherein each of said plurality of ridges has a substantially rectangular profile. 
     
     
         9 . The roofing underlayment of  claim 4 , wherein each of said plurality of ridges is arcuate. 
     
     
         10 . The roofing underlayment of  claim 9 , wherein each of said plurality of ridges is sinusoidal. 
     
     
         11 . The roofing underlayment of  claim 1 , wherein said at least one ridge is sized and shaped so as to fold upon itself when a downward force is applied thereto. 
     
     
         12 . The roofing underlayment of  claim 1 , wherein said felt includes at least one of organic fibers and inorganic fibers impregnated with said coating material. 
     
     
         13 . A method for making a roofing underlayment, comprising the steps of providing a flexible sheet felt; and deforming portions of the sheet felt so as to form a plurality of upwardly projecting ridges thereon. 
     
     
         14 . The method of  claim 12 , wherein each of the ridges is flexible such that it is collapsible when a downward force is applied thereto. 
     
     
         15 . The method of  claim 13 , wherein said deforming step is performed by passing the sheet felt between a pair of rollers urged against each other. 
     
     
         16 . The method of  claim 14 , wherein one of the rollers includes a plurality of grooves and the other of the rollers include a plurality of projections, each of which is sized and shaped so as to mate with a corresponding one of the grooves.