Weatherproof underlayment with high filler content polymer asphalt layer

Abstract

A roofing membrane underlayment material includes a fibrous mat generally encapsulated within a non-adhesive asphalt coating, the resulting encapsulated mat having an adhesive asphalt layer applied to one surface thereof, typically the bottom surface. An acrylic, talc or granular coating is applied to the surface of the encapsulated mat that is not in contact with the adhesive asphalt layer. The non-adhesive asphalt coating is characterized in that it includes a high filler content made possible by the use of non-oxidized flux asphalt to which has been added a small percentage of an asphalt additive such as radial or linear polymer or other elastomer. The resulting membrane, when applied to a roofing deck, provides a high traction surface that will not adhere to shingles and provides an effective waterproofing seal on the roofing deck and is flexible in both hot and cold environments.

Description

TECHNICAL FIELD [0001] The present invention relates to roofing and other similar underlayments and more particularly, to underlayments having a fibrous mat having at least a top surface coated with an asphalt layer including flux or non-oxidized asphalt, a copolymer and a high filler content. BACKGROUND INFORMATION [0002] Asphalt based roofing shingles are presently installed on approximately eighty percent of the homes in the United States. In areas where snow accumulates, roof shingles can develop leaks as a result of ice dams which can form along the eaves of a roof. Ice dams form as the result of a differential temperature which occurs between the eaves of the roof and the interior sections of the roof. The temperature differential occurs when heat rises into the attic space. Under certain temperature conditions, snow collected on the roof surface will melt along the upper interior portions of the roof and then freeze when the liquid snow-melt reaches the cooler eave section of...

AI Technical Summary

Benefits of technology

"The present invention is about a new type of roofing membrane that has a fibrous mat surface that provides traction, structural integrity, and lap sealing capabilities. The membrane has an adhesive surface provided by an adhesive rubberized asphalt layer and a non-adhesive surface provided by a woven or non-woven fibrous mat encapsulated within a non-adhesive asphalt coating. The adhesive rubberized asphalt layer is very adherent and provides excellent adhesion to a roof deck, while the encapsulated fibrous mat provides a surface having excellent traction and lap sealing characteristics. The non-adhesive top surface can also be coated with a polyethylene composite or other polymers, minerals or the like to enhance its non-slip characteristics. The preferred material for forming the fibrous mat is fiberglass or polyester. To prevent multiple layers of the membrane from adhering to one another during shipping and storage, a release sheet can be applied to the lower, adherent surface of the rubberized asphalt layer. The invention provides a rubberized asphalt roofing product that is flexible in both hot and cold weather, performs well in both hot and cold weather, and is non-slip for the safety of roof installers. It also allows for easy removal and replacement of shingles, if necessary, and reduces the cost of the manufactured product by reducing the amount of asphalt needed."

Problems solved by technology

In areas where snow accumulates, roof shingles can develop leaks as a result of ice dams which can form along the eaves of a roof.

Ice dams can also occur as a result of frozen slush accumulating in gutters, also causing liquid to collect and leak through the roof.

As noted above, ice dams are formed by the continual thawing and freezing of melting snow, or the backing up of frozen slush in gutters, which force water under the roofing, thereby causing damage to a structure's ceilings, walls, and insulation.

Typically, the asphalt used in the fifty-pound felt is not modified with rubber, and after aging, will not form a good seal around nails.

Additionally, the installation of two layers of 15-pound saturated felt consumes undesirable amounts of time and also will not seal around nails.

Although this and similar products have been quite successful, the oxidized asphalt layer which is used to impregnate the fibrous mat on the upper surface of the underlayment, and which serves to allow the top surface of the underlayment to be walked upon and not stick to the roofing material, makes the finished product quite brittle.

This problem is particularly acute in Northern or other cold weather regions.

Finally, an additional problem is the rising cost of asphalt which has considerably driven up the price to manufacture such a product.

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