Slip-resistant roofing felt
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.