Roofing Material

Abstract

An expanded plastic roof product having a first layer of open cell expanded material, the material being preferably a polyolefin on density from about 1 to about 25 pounds per cubic foot and there being additional layers thereon for weather protection, coloration, styling and appearance preferably like that of current roofing materials.

Description

SUMMARY OF PROBLEM AND SOLUTION

Roofing products currently available for residences, commercial buildings, apartments, factories and the like, may be generally classed in the following groups. A number of buildings are covered with metal surfaces, tiles, stone, slate, and the like. Such materials are so very expensive as to be excluded from the greater bulk of the market of roofing material. Additionally, built-up roofs typically formed of asphalt and gravel require custom installation, and hence, are likewise quite expensive. The greater bulk of roofing material used today includes either wood shingles or asphalt shingles. Wood shingles typically are formed of cedar or other untreated naturally occurring wood products, and, as a generalization, serve as a prestige home roofing material. However, problems exist with regard to availability, price, flammability, limitations in color and shape, and difficulties of piece-meal installation.

The greater portion of the home roofing market is served by various grades and qualities of asphalt shingles. By asphalt shingles, reference is had to the shingle which is formed of a typically fibrous base of felt or similar matter which is impregnated with low grade asphalts and which is imbedded with colored granules to give a surface texture and color. Briefly, asphalt shingles have been found wanting in numerous regards in that they are brittle and have very low mechanical strength. They must be applied in a piecemeal fashion utilizing expensive hand labor. They are as flammable as cedar shingles, and provide negligable insulation to the building. Particularly damaging, asphalt shingles have been found wanting in life in that, dependent on the sun load and weather in a particular climate, aging effects color, tendency to break or fracture and form openings in the roof which initiate leaks into the building proper.

Moreover, the installed asphalt roof is particularly susceptable to weather damage. Hail stones of any size tend to at least dent the asphalt shingle, and the dents become fractures or breaks which seriously accelerate leakage of the roof. Even though individual shingles are quite heavy, and even though they are nailed to the roof in an overlapping fashion, nevertheless, surface winds of moderate velocities have little difficulty in getting beneath a single shingle and peeling it back from the rest of the roof. Once this happens during a storm or other inclement weather, an entire portion of the roof may be peeled back and blown away. Once a shingle is bent to any extent, the portion which is bent upwardly breaks free of that portion which is nailed to the roof, and also tends to bend upwardly and away from the roof the nearby shingle. Hence, a wind storm may begin peeling shingles from a portion of the roof and the entire area of the roof to the crown or peak of the roof will be denuded. Because of these factors, asphalt shingle roofs have a limited life, perhaps in the range of 10 years, in most climates.

With the foregoing in view, it will be observed that the roofing products which predominate in the home market, and in a great number of the smaller commercial buildings, have been measurably found wanting in numerous regards. Further, in the event of a fire at a nearby location, burning embers and even larger and heavier fire brands are lifted by the updraft at the point of the fire and are typically wind borne to fall out on nearby or surrounding buildings. It is not uncommon for a spark to fall on the roof of a house located several hundred feet or a fraction of a mile away and initiate a fire on that roof. Typically the ember or fire brand will fall on the roof and start a fire at the spot of contact, which will spread on the roof and penetrate into the upper portions of the structure.

The apparatus of the present invention overcomes these and other deficiencies, and further provides a roof which has an essentially indefinite life. That is to say, the life of the roof of the present invention is approximately equal to that of the structure itself, and more specifically, appears to be in excess of 30 years, ranging upwards to 45 or 50 years.

The present invention is summarized as providing a roof formed of a base material in the range of preferably 1/4 to about 3/4 inch thickness, formed of an expanded plastic sheeting which provides insulative thermal properties and which is flame resistant. More specifically, one embodiment of the present invention envisions the use of a foamed polyolefin base in the range of about 1 to 25 pounds per cubic foot, after foaming, with the preferred weight being approximately 4 pounds per cubic foot. The base is utilized, as will be described in several species of the present invention, to receive a pigmentation for stability, weatherability, and coloration. Moreover, one embodiment of the present invention envisions the use of a secondary sealant placed on the exposed or outer surface of the expanded plastic sheeting to serve as a sealant, adhesive, surface appearance means, and for other purposes as will be denoted. In further particular, a third layer can be added to totally simulate roofing products to which the public has grown accustomed, namely the use of small colored granules of numerous sizes and weights with which to simulate asphalt shingles, all embodiments of the present invention being adapted to be shaped in various sizes and widths and to take on surface imprints, surface variations, to either simulate products currently known in the market place and well recognized by the purchasing public, or to implement new or unknown surface appearances.

Briefly, many objects and advantages of the present invention will become more readily apparent from a consideration of the following specification which describes the present invention, and its preferred embodiment, numerous species thereof, all without drawings.

Considering the present invention first generally, the present invention envisions the use of an expanded plastic sheeting to be placed on the roof of the structure. The expanded plastic sheeting preferably covers the entirety of the roof, and at this juncture, it is sufficient to note that it may take on any surface appearance, may be installed in any acceptable manner, may have variations in cross section such as needed to simulate other products, and may be adapted or varied from the preferred embodiments set forth herein in numerous ways. For ease of discussion, the preferred embodiment will be described as an essentially rectangular sheet of generally uniform cross section although the variations and alterations generally referred to above may be introduced without departing from the scope of the present invention.

The expanded plastic of the present invention preferably utilizes a polyolefin foam. The foam preferably has a weight of approximately 1 to 25 pounds per cubic foot of the completed product. The 1 pound limitation noted above is governed primarily by the need to provide some mechanical strength, and foams lighter than one pound per cubic foot are also essentially commercially unavailable. The limitation of approximately 25 pounds per cubic foot is governed by economics, and, as the density increases, the thermal conductivity of the completed product likewise increases. To obtain the good insulation characteristics of the present invention, the foam is preferably maintained materially lighter than the 25 pound limitation noted above. Also, the economics of the base material are materially improved through the use of a lighter foam.

Suitable polyolefins found acceptable for the present invention include polyethylene, polypropylene, and numerous copolymers which include ethylene as a principal or major component. Numerous manufacturers commercially market these polyolefins either in bulk or in the completed foam sheeting in several thicknesses. Further, the commercially available materials for the present invention may be obtained with or without the additives described hereinafter added so that the point in time and procedure of mixing the various additives is immaterial to the present invention.

Utilizing the principal polymer or copolymer, as the case may be, denoted above, the polymer is foamed to the approximate range of finished densities noted above. The foaming agent selected for the present invention is not considered critical for the present invention and may be any of commercially available foaming agents. For instance, the freon series may be readily used to form the closed cell bubbles in the finished product to achieve the range of densities noted above for the preferred version. The foaming agent may include those materials which at least partially or totally evolve gas under controlled conditions such as an elevated temperature. Numerous inorganic compounds break down and evolve gas under elevated temperatures, and one example is sodium bicarbonate. Also, organic chemicals such as the above mentioned freon series simply vaporize to form substantial volumes of gas in comparison with the volume of material in the liquid or solid state. It is immaterial whether or not the foaming agent leaves a residue as in the case of sodium bicarbonate, or whether the entirety of the foaming agent evolves into a gaseous material. Typically available foaming agents include commercially available products sold under the names "Uni-cell," "Celogen," and "Freon 12 " or "Freon 114 ."

The expanded plastic sheeting of the present invention preferably includes an ultraviolet absorber to enhance and improve its weatherability. The ultraviolet radiation from the sun tends to embrittle unprotected polyolefin products. The present invention preferably incorporates an ultraviolet inhibitor or a covering which, in and of itself, reflects, absorbs, or otherwise prevents the ultraviolet radiation from reaching the foamed or expanded plastic sheeting of the present invention. When the polyolefin per se is exposed to sunlight, a small quantity or measure of the inhibitor is preferably dispersed throughout the completed product to protect it from the cracking and crazing noted above. One suitable ultraviolet inhibitor is finely divided carbon black. While other inhibitors are known, carbon black is materially less expensive and has been found perfectly satisfactory for this purpose. The range of carbon black to be added to the present invention as an ultraviolet inhibitor is from a low of perhaps 11/2 percent for a very finely divided carbon black such as channel black, to a high of perhaps 5 to 10 percent by weight for a coarse but cheaper thermal carbon black. As will be seen, the fineness of the carbon black particles reduces the percentage by weight required to achieve the desired inhibition of ultraviolet penetration. This materially is related to the weatherability and long life of the present invention.

Untreated foamed polyolefins will be recognized as being "slow burners" by those skilled in the art. If total fire retardancy is desired, numerous additives may be added to the foamed plastic sheeting of the present invention to render it self-extinguishing. By way of example and not limitation, suitable flame retardants include antimony trioxide with a chlorine source. Such flame retardants are readily available commercially from numerous manufacturers. The flame retardant ranges from 0 percent upward to perhaps 20 percent or more by weight of the finished product dependent on degree of flame retardancy desired. As will be recognized, if no flame retardant is added, the foam base is "slow burning" as noted above. The degree of retardancy desired at least partially controls the amount of retardant added, although in a construction which includes a nonflammable but intimate second layer, there is little incentive to load the base with fire retardants.

The preferred flame retardant noted above tends only to slightly affect the color or appearance of the finished product. A small percentage of carbon black renders the completed product, whether fire retarded or not, totally black. Coloring pigments may be added to the product although one species of the generic invention to be described hereinafter will obviate the need of adding a pigment to the foamed base of the present invention.

Summarizing the material and the various aspects only to this juncture, it will be noted that a foamed material having a closed cell structure which is ultraviolet inhibited and which may be made flame retardant, as taught previously, is provided. The thickness and other dimensions of the product may vary widely, although suitable insulation and mechanical qualities as a roofing material are achieved with thicknesses in the range of about 1/4 to about 3/4 inches thickness.

To this juncture, little has been said of the manufacture of the present invention. The preferred embodiment of the present invention is preferably extruded to a desired shape, width and thickness. Locking devices, step shingles, and other cross sectional devices may be incorporated in the completed product in the extrusion process. Preferably, the extruding and foaming process occurs simultaneously, and as the product is derived from the extrusion equipment, it may be processed by other machinery, such as print rolls, embossing rolls, and other apparatus which will further alter the size, shape, contour, surface finish, and other factors of the completed product. Of significance is the fact that the extrusion process maintains the individual discrete cells in the flowable product a small size and prevents their congregating into larger bubbles which materially effect the mechanical characteristics of the completed product. In brief, a small cell size is desirable for the mechanical characteristics of the completed product, proper thermal characteristics, and appearance factors. In brief, large bubbles in the completed product are not desirable and are readily eliminated by proper manufacturing techniques.

To this juncture, a product has been described which is totally and completely functional and operative as a roof which has the many features set forth in the present disclosure. The material described may be used by itself inasmuch as it fulfills the function of a roof. However, additional flexibility is achieved and certain improvements are obtained as will be noted. For instance, an outer coating may be applied to the base material. Many coatings which impart either visual or sealing characteristics to the base material, that term being applied hereinafter to the expanded plastic sheeting described briefly and in detail hereinabove, may be added. By way of example, the appearance of the base material may be enhanced through the application of a colored coating to achieve a desired or simulated result. A sealant may be applied such as various rubber based materials including, by way of example and not limitation, a coating of neoprene. It serves as a secondary sealant inasmuch as the base material, described above, is also a weather proofing layer which is one of the primary functions of a roofing material. The preferred embodiment of the present invention best utilizes a neoprene layer which serves as the secondary sealant, as an adhesive for purposes to be described, and as a further covering which enhances all the characteristics of the present invention. The neoprene layer is of nominal thickness, in the range of perhaps 2 to 10 mils. It is not necessary to make it any thicker for the purposes described above, and, in view of the cost, the thickness is preferably limited.

The neoprene coating is applied to the base material either dissolved in a suitable solvent or by applying a sheet with a suitable adhesive to the material. In either case, the neoprene is allowed to dry on the base material and form the uniform, leakproof layer.

The use of a neoprene layer serving as a secondary sealant is particularly advantageous when the exterior appearance of the roofing material is modified to simulate a particular roofing material presently in common use. Solvents for maintaining the neoprene in a tacky state on the upper surface are readily known, and, in conjunction with such solvents, colored rock granules may be applied to the roofing material and pressed into the neoprene. Thus, a three layer roof is formed comprising the base material defined above with all the features noted thereat, a secondary sealant which is also used as an adhesive, and a granular layer of material which simulates roofing products as presently on the market. The granules are typically rock or other ceramic materials, and are of suitable fineness to comprise several thousand particles to the pound. As a matter of fact, the rocks, chips, or granules currently in use with asphalt shingling are quite acceptable for this purpose. The present invention is also material improvement over asphalt roofing in the fact of the degree of attachment of the rocks or granules to the roofing. In asphalt shingles, the granules are merely pressed into the soft or tacky asphalt and are easily detached. However, the present invention actually bonds the granules to the roofing material and the tendency of the granules to flake or otherwise fall from the roof is considerably reduced.

The granules and neoprene coating which comprise portions of the preferred embodiment are applied in the following manner. The sheet of base material is coated on its upper surface with a layer of neoprene in the tacky state. The mode of application may be sprayed, brushed, rolled, etc., by any suitable process for this purpose. The rocks, granules, chips, or the like, are then sprinkled generously on the neoprene layer while tacky. Preferably, a roller under moderate pressure passes over the surface after sprinkling with granules and the granules are pressed into the tacky neoprene. At this juncture the granules are totally and completely joined to the neoprene and are bonded into the roof. Of course, there may be a surplus of chips which may be brushed, blown, or otherwise mechanically removed from the surface. At this juncture, the outer surface has then been so modified to simulate the appearance of products currently on the market, and the size and shape may be obtained through the use of a scoring wheel or other cutting apparatus.

The foregoing describes the method of modifying the present invention to simulate conventional asphalt shingles. It is likewise possible to simulate cedar shingles. Of course, a different texture material having different colors and striation marks is required. Again, this is a matter of artistic detail and the particular coloration ingredients selected may likewise be varied. In any event, the present invention provides a means whereby cedar shingles or other wooden shingles may be simulated through the application of a coloring agent on the outer surface, passing the roofing material beneath a suitable embossing wheel or the like, cutting the roof to shape, and conforming the thickness with that of the roofing material to be simulated. Without going into the details thereof, it is believed that the present apparatus provides a roofing material whereby the foregoing may be accomplished.

The roofing material of the present invention is preferably formed in sheets of arbitrary dimensions. Should the roofing material be applied to a house of 50 foot width, clearly the sheets can be 50 feet in length. The width is variable also. It may be formed in strips of relatively narrow widths with a view of simulating products currently used as roofing materials, or the sheeting material may be formed quite wide so that only two or three strips are required on a roof. The roofing material is particularly lightweight and moreover, is inexpensive to transport, is easy to lift from the ground onto a roof at a building site location, and does not require excessive labor to actually lay and install. The roof of the present invention as described hereinbefore is particularly long lived. The base material as noted above has an essentially indefinite life which approximates that of the basic structure itself. When a secondary sealant layer is used, either for this purpose singly or as an adhesive, the preferred material noted above does not in any way or manner decrease the life of the roofing material. The insulation properties are particularly to be noted. Presently, asphalt shingles provide essentially no insulation properties. The same is also true of cedar shingles. In view of the fact that the two most common residential roofing materials provide little, if any, insulation, most houses now built incorporate a substantial thermal barrier in the attic or ceiling to at least protect the living quarters of the house. It is legend that the attics of most houses in the summer time will rise to temperatures in the range of perhaps 150.degree. F. or greater, dependent upon the shade available, the color of the roof, the outside temperature, and other factors. The roof of the present invention provides a considerable improvement over the insulation qualities of asphalt shingles as customarily installed heretofore. In fact, the heat transfer rate through the foam base is about one-twentieth of that for asphalt shingles.

While many other advantages and virtues of the present invention may be noted, it is sufficient to define the foregoing preferred embodiment, several variations thereof, and to note the various forms and shapes which the present invention may assume. Numerous variations and expansions on the preferred embodiment may be adopted by one skilled in the art. However, the definitions included herein in the specification extend to the claims which are appended hereto.

Claims

What is claimed is:

1. A roofing material having the appearance of a typical roofing material and being adapted to be exposed to the weather, comprising:

a. a first layer of about one-fourth to three-fourths inch thickness of a flexible, bendable foamed aliphatic polymono-olefin having a closed cell structure with a density in the range of about 1 pound to about 25 pounds per cubic foot;

b. an outer layer of opaque chips spread generally evenly over the exposed surface of said first layer; and,

c. an adhesive material extending over said first layer for joining by embediment and adhesion said opaque chips to said first layer.

2. The invention of claim 1 wherein said first layer includes an ultraviolet inhibitor dispersed therein.

3. The invention of claim 2 wherein said ultraviolet inhibitor is finely divided carbon black.

4. The invention of claim 3 wherein said carbon black ranges from about 11/2 to 51/2 percent by weight of said fist layer.

5. The invention of claim 1 in which said adhesive material is a thin layer of neoprene which is applied coextensive with the surface of said first layer and extends fully thereover and serves as a secondary sealant.

6. The invention of claim 3 wherein said first, outer, and adhesive layers have a weight approximating 20 to 50 pounds per roofing square.

7. The invention of claim 1 wherein:

a. said first layer is formed of foamed polyethylene and has therein a flame retardant additive ranging up to about 20 percent by weight;

b. said adhesive layer is neoprene in a thickness of up to about 0.050 inches thick; and,

c. said opaque chips are sufficient in quantity to prevent the sun's ultraviolet rays from reaching said first layer.

8. The invention of claim 1 including from approximately 0 to approximately 20 percent by weight of flame retardant material.

9. The invention of claim 8 wherein said flame retardant material at least includes a portion of antimony trioxide.

10. The invention of claim 9 wherein said antimony trioxide is in the presence of a chlorine liberating material.

11. The invention of claim 5 wherein said Neoprene is approximately 0.001" to 0.050" thick.

12. The invention of claim 1 wherein said first layer is formed of polyethylene.

13. The invention of claim 2 wherein said first layer is comprised substantially of polyethylene.

14. The invention of claim 5 wherein said thin layer of neoprene is joined to said first layer which is formed of polyethylene.

15. The invention of claim 5 wherein said thin layer of neoprene has a thickness of up to about 0.05 inches.