Skid-resistant roofing underlayment
AssigneeW. R. Grace & Co.-Conn.
InventorsRobert Alan Wiercinski, Robert Francis Jenkins
Life of this patent
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Abstract
An exemplary skid-resistant roofing underlayment provides a pressure-sensitive membrane attached to a carrier support sheet having at least two different plastic films, the carrier sheet being corrugated with ridges in the machine direction to provide skid resistance when the underlayment is installed on a sloped roof. Especially preferred are corrugated, cross-laminated composites having a polypropylene or high density polyethylene layer co-extruded with a linear low density polyethylene layer. An exemplary method for making the roofing underlayment involves corrugating at least two different plastic film layers to provide a carrier support sheet for a waterproofing membrane adhesive layer.
Claims15
A flexible sheet-like roofing underlayment comprising:
- a pressure-sensitive waterproofing adhesive layer comprising a material selected from the group of rubber bituminous material and synthetic material, said waterproofing adhesive layer being attached to a continuous multi-layer carrier support sheet on a major face thereof, said carrier support sheet comprising corrugations of at least 5 ridges per lineal inch and at least four film layers wherein a first film layer has a first direction of orientation and wherein another film layer has a second direction of orientation different from said first direction of orientation, at least one film layer of said at least four film layers being located outermost of said layers, said ridges being aligned in a machine direction of said carrier support sheet, such that, when installed in a direction perpendicular to the direction of roof slope, said ridges are operative to minimize skidding of foot traffic on the underlayment, each of said at least four film layers having a direction of orientation about 40-50 degrees from the direction of said ridges, said carrier support sheet having an average thickness and said ridges having a height of 1.25-20 times the average thickness of said carrier support sheet;
- and said carrier support sheet, on a major face opposite said waterproofing adhesive layer, further comprising a coating having a lower Young's modulus of elasticity than the outermost of said at least four film layers of said carrier support sheet.
A method for fabricating a roofing underlayment comprising attaching a pressure-sensitive waterproofing adhesive layer, comprising a material selected from a rubber bitumen and synthetic material, to a carrier support sheet on a major face thereof, said carrier support sheet comprising at least four film layers and having corrugations of at least 5 ridges per lineal inch, at least one of said at least four film layers having a first direction of orientation and another of said at least four film layers having a second direction of orientation different from said first direction of orientation, at least one film layer of said at least four film layers being located outermost of said layers, said sheet having ridge-shaped corrugations in a machine direction, such that when installed on a roof-top perpendicular to the roof slope, said ridge-shaped corrugations are operative to minimize skidding of foot traffic on said underlayment, said at least four film layers each having a direction of orientation about 40-50 degrees from the direction of said ridge-shaped corrugations, and said carrier support sheet, on a major face opposite said waterproofing adhesive layer, further comprising a coating having a lower Young's modulus of elasticity than the outermost of said at least four film layers of said carrier support sheet.
Dependencies are inferred from the claim text.