Waterproofing Membrane For Use on Inclined Surfaces

Abstract

The present invention provides a waterproofing membrane for use on inclined surfaces. The membrane is fabricated from one or more layers of flexible sheet material preferably consisting of woven or nonwoven synthetic polymers of polypropylene. A skid resistant pattern of polymer elements is applied to the top surface of the membrane. The polymer has a Tensile Modulus<15 MPa (ASTM D638, 23C, 50 mm / min), a Tensile Yield Elongation>50% (ASTM D538, 23C, 50 mm / min, and a Shore A Hardness (ASTM D2240, 23C, 0 sec)<90. In a preferred embodiment the polymer elements are made from polyvinyl chloride polymer with a Tensile Modulus<7 MPa (ASTM D638, 23C, 50 mm / min), a Tensile Yield Elongation>50% (ASTM D638, 23C, 50 mm / min, and a Shore A Hardness (ASTM D2240, 23C, 0 sec)<75. The pattern of polymer elements may be applied directly on the top surface of the membrane or produced on one side of a carrier sheet which is attached to the top surface of the membrane.

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to a waterproofing membrane for use on inclined surfaces having a skid resistant pattern of discontinuous polymer elements applied to the top surface of the membrane. In particular the waterproofing membrane may be used as a roofing underlayment in steep slope roofing applications, where it functions as a secondary water shedding layer applied originally beneath the primary roofing cover such as composition shingles, tile, metal, cedar shake, and the like.BACKGROUND OF THE INVENTION[0002]In recent years, synthetic polymer waterproofing membrane materials have been introduced to the North American market to replace traditional bituminous asphalt tar / felt paper roofing underlayments in steep slope (>2:12 pitch vs. flat roof) roofing applications. These synthetic materials possess several advantages over the traditional asphalt paper such as greatly improved tensile and tear strength, reduced tendency to tear away f...

AI Technical Summary

Benefits of technology

[0009]In a preferred embodiment the waterproofing membrane provides a substantially improved steep slope, wet surface skid resistant performance roofing underlayment, whilst overcoming many of the commercial, technical, production, and wide ranging application specific (i.e. roof slope, wet condition, loading dynamics, primary roofing material type) performance issues of the prior art products.

Problems solved by technology

Although synthetic roofing underlayments possess several significant advantages over traditional asphalt paper, they generally suffer from poor skid resistant properties, most especially under steep slope wet surface conditions.

The greatly reduced coefficient of friction in wet conditions experienced by low skid resistant synthetic roofing underlayments is a significant limiting factor to their enjoying accelerated market penetration in North America as a product class.

When this skid resistance factor is combined with their higher cost as compared to commodity asphalt felt paper, this is dual challenge to greater market acceptance.

In addition to cost, a roofing applicator will not likely continue to use a product which has such high inherent safety risk issues, both for personal safety, and equally as important, for the securement of various objects temporarily loaded onto the roofing underlayment surface during roof installation (packages of shingles, roofing tiles, etc), which would result in serious safety hazards should they randomly fall from the rooftop surface.

As well, the type of design used in European homes is different (warm roof) than generally found in North America (cold roof), and this has required the use of moisture breathable roofing membranes, of which engineered synthetics have largely satisfied this need (asphalt paper lacks the sufficient inherent breathability).

All claim some level of skid resistance, but none produce superior or “good” or “excellent” performance as compared to typical asphalt paper under a wide variety of surface loading dynamics found in typical steep slope, wet surface conditions applications.

A review of the extensive prior art products found in Table 1 clearly indicates the current state of the art is significantly lacking in the availability of a “good or “excellent” rated, polymer based skid resistant surface for steep slope, wet condition roofing underlayment applications vs. traditional 30# asphalt felt paper.

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