US2705209A - Roofing - Google Patents

Description

March 29, 1955 w. w., ROWE 2,705,209

ROOFING Filed April 19, 1947 i y IN VEN TOR..

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ATTORNEYS.

United States Patent O 4 Claims. (Cl. 154-51) Cincinnati, Ohio, assignor to Inc., Lockland, Ohio, a corpo- This application is a continuation-in-part of my copend ing application, Serial No. 389,961 of the same title, tiled April 23, 1941, now abandoned.

My invention pertains to roong in which the resistance of the structure to water and weather depends upon the use of bitumen or equivalent substance in a heavy, discrete layer serving as a waterproof membrane.

In the manufacture of current prepared roofing a dry felt, which is a relatively heavy, porous, felted sheet containing a considerable percentage of rag iibers is saturated with a saturating type asphalt, then coated with a heavy continuous layer of a relatively non-saturatng type asphalt.

Built-up rooting is similar in general structure except that it is assembled on the job. Saturated felt is nailed to a wooden deck or is mopped onto a concrete deck with hot asphalt; and a roof covering is built-up in plies mopped together by means of a high melting point asphalt. A top layer of the asphalt is also applied over the topmost layer of felt. In each instance, the weather resistance and waterproof character of the rooting is dependent upon the integrity and continuity of a relatively heavy layer of coating asphalt, or a plurality of such layers.

The coating of asphalt is not perfectly weather resistant, but is subject to a progressive deterioration. Under the influence of actinic light and the weather, the surface of the asphalt takes on a hard crusted condition, frequently referred to as an oxidized condition. The hard external crust cracks or crazes along a `multitude of lines, exposing a fresh asphaltc surface at the cracks. This surface in turn becomes hard and crusted, and a continuation of the cracking and crazing deepens the cracks into canyons or valleys which eventually progress throughout the thickness of the asphaltc layer.

Covering substances such as the crushed slate frequently applied to prepared roongs and the gravel frequently applied to built-up roongs delay this action somewhat but do not prevent it. Since the utility of the rooting depends upon the integrity of a continuous, relatively heavy layer of asphalt or other bitumen, the result of this progressive deterioration adversely affects the life of such roofing materials.

The principal object of my invention is the provision of a rooting fabric or roong structure which, while dependent for its effective life on the integrity of a heavy, continuous layer of bitumen or its equivalent, is nevertheless not subject to the rapid and progressive disintegration of such a layer n the manner described above, and hence has much longer life. It is an object of one aspect of my invention to provide protective means for rooting of otherwise conventional type to prevent or greatly delay the progressive destruction of the bituminous layer. It is an object of other aspects of my invention to provide roofing fabrics which are not constructed like those heretofore known in the art, but have novel and improved structures as will hereinafter be set forth. My invention is applicable to the provision of prepared roongs or substitutes for prepared roongs which may be applied in roll form or in the form of cut pieces such as shingles or strips. It is also applicable to the production of prepared rooting materials or substitutes for them which may be employed on the job in the construction of so-called built-up roofs.

The invention is based upon my discovery that the association, with an otherwise exposed thick layer of bituminous substance or its equivalent, of an external web which is universally contractible and expansible i. e., readily stretchable and contractible in all directions, acts to prevent the cracking and crazing aforesaid and hence the progressive deterioration of the said thick layer. The type of universally expansible web which I employ is one which has been gathered in a plurality of directions so as to be stretchable in all directions, and such a web is preferably formed by creping.

The weather resistance of the stretchable web by itself is not of fundamental importance. While cloth may be employed, I have found that creped paper is sufcient as a covering layer, and when so used will add years to the useful life of a rooting fabric. The universal stretchability is, however, a requirement, and webs which are not stretchable at all or are stretchable in but one primary direction will not serve to prevent the progressive disintegration of the bituminous layer.

Without wishing to be bound by theory, I nevertheless believe that the reason for the progressive disintegration of a bituminous layer in exposed rooting products, in View of the crusting action, is primarily a matter of expansion and contraction. The initial cracking or crazing of the so-called oxidized crust is due to expansion of the bituminous layer against the inexpansible crust. The expansion or contraction of a base or support bearing the bituminous coating is not of primary consequence although it may to some extent affect the expansion and contraction of the bituminous layer. When the cracks have once been formed, further oxidation of the bituminous surfaces in the cracks, accompanied by further expansion and contraction, works the cracks down into the body of the layer until presently along the lines of the cracks the body becomes completely cut through and the base is exposed to the weather.

A covering imposed upon a heavy bituminous layer, insofar as it protects the surface of the bituminous layer from the weather, oxidation and actinic light, might be expected to prevent the formation of the initial crust. But a non-expansible web, such as a web of plain paper or a web which is stretchable in but one direction', in adhesive union with a heavy bituminous layer, is itself subject to the expansion and contraction of the bituminous layer and will split or crack in one or a plurality of directions if subjected to expansion and will lose bond if subjected to contraction. When these cracks are formed, the oxidation of the bituminous layer occurs in them, and the action of the progressive deepening of canyons in the bituminous layer begins and continues to the complete destruction of that layer. This action s similar to the destruction of the bituminous layer under such discontinuous coatings as slate, sand, gravel or the like. A web which is universally. expansible, however, follows the movements of the bituminous layer and does not itself crack. Hence, it not only prevents the formation of a general crust over the 'whole surface of the asphaltc layer, but prevents the formation of any exposed cracks which, being subject to crusting, could progressively deepen. It is further remarkable that an external layer of universally stretchable paper, in intimate adhesive association with a heavy bituminous layer seems to acquire a property of relative indestructibility from weathering. A piece of universally stretchable paper which, exposed by itself or with'a thin coating of bitumen to the weather would rapidly disintegrate will, if associated throughout its area with a heavy, unitary layer of bitumen, retain for many years its bond and hence a suficient integrity to protect that layer of bitumen from progressive disintegration, even though the paper is itself directly exposed to the weather. It desired, however, the paper may itself be protected by a paint which has in# herent elasticity or which follows the contours of the crepes.

In one aspect, it is an object of my invention to provide protection for hitherto known types of prepared roongs as aforesaid by providing in association with the normally exposed surface of a heavy layer of bituminous substance, an external covering which is a universally stretchable web. In another aspect of my invention, it

. is my object to produce improved roofing fabrics by asf sociating two or more heavy layers of bitumen with intermediate and external universally stretchable webs.

I am awarethat multiple products comprising univer` sally stretchable webs adhered together by coatings of asphalt, with or without interior reinforcement, have been made in the art and have been used as building or wrapping papers. Because such papers have a certain degree of water resistance they would, if attached to a roof, give temporary protection against the Weather. Such products, however, have mented together with such amounts of bitumen as are required for plying purposes. When subjected to the weather the useful life of these materials is extremely short. The product tends to delaminate, and the stretchable paper webs weather away and disintegrate. Because such bituminous coatings have no entity or integrity apart from the paper, they disintegrate physically along with the paper. The structure in the course of time becomes a pulpy mass and in effect washes away. Resistance to the Weather such as is required in a product serving the purposes of commercial roofing is dependent upon a layer of bitumen so thick as to act as an independent and discrete entity apart from any base or covering with which it is associated. Such a layer of bituinen is, however, subject to its own independent ilow or movement and expansion and contraction and, in the unprotected state, to the progressive disintegration which has been described and which it is an object of this invention to prevent or greatly delay.

These and other objects of the invention, which will be clear from what has been said above, which will be pointed out hereinafter, or which will be apparent to one skilled in the art upon reading these specications, I accomplish in the structures and arrangement of parts of which I shall Vnow describe certain exemplary embodiments. i

Reference is made to the accompanying drawings, wherein:

Figure l is a partial cross-section of one type of roofing fabric made in accordance with my invention.

Figure 2 is a similar view showing an edge treatment thereof.

Figure 3 is a partial cross-sectional view of another type of rooting fabric made in accordance with my invention.

Figure 4 is a similar view showing an edge treatment thereof.

Figure 5 is a similar view showing edge treatment.

Figure 6 is'a partial cross-sectional view of a built-up roof Amade in accordance with my invention.

Figure 7 is a diagrammatic elevational view showing an apparatus and method of providing seam forming means in connection with my rooting.

Figure 8 is a plan view of a piece of my rooting fabric showing seam forming means.

Figure 9 is a partial perspective view showing a mode of seam formation.

Figure 10 is a partial sectional view taken across the seam of Figure 9.

By a heavy discrete layer of bitumen, I mean a continuous layer of the substance of a thickness which enables it to leave its own mode of expansion, contraction, flow and movement irrespective of a support or covering web. In the prepared and built-up rooiings of commerce, the asphalt coatings range approximately from lb. to lb. of the bitumen per 100 square feet (or square of 108 sq. ft.) of the roofing fabric. The saturated felt employed will usually be from 15 to 30 pounds per square. While this is a weight ratio of around l: or in excess thereof, it will be understood that the layer of bitumen is thick in the absolute sense.

In the manufacture of building papers, a coating of plying asphalt on a paper web will normally have a ratio of 1:1 or less; but because paper does not compare in thickness with saturated felt, the layer of asphalt will be thin in the absolute sense.

In my products I associate a covering web of universally snetchable paper with a layer of bitumen which in weight or thickness will have a ratio to the paper of 3:1 or more in most instances. The independent ilow action of a layer of bitumen will bear a relationship to the thickness of the paper; but in instances where a 3:1 or greater ratio is not maintained (as where an exceptionally heavy paper is chosen without a proportional increase in the another kind of consisted of the stretchable webs cebituminous layer) I do not employ a bituminous coating less than about 8 lb. to l0 1b. per 100 square feet. It may be made thicker with improvedresults, the upper limit being a thickness, in view of the characteristics of the bitumen itself, which might permit creeping of the bituminous layer at high temperatures on a roof of the pitch for which a particular roofing is designed. The biturnen itself should be of the coating type as known in the rooting industry. A satisfactory exemplary asphalt is one having a ball and ring softening point of approximately 180-200 degrees F. and a penetration at 77 degrees F., 100 grams, 5 seconds, of approximately 20 according to the A. S. T. M. standard.

The stretchable webs which I employ are webs of paper which have been creped so as to be universally stretchable. Preferably, this is done in accordance with the teachings of Patent 2,008,181 in the naine of Kemp. Any available papers meeting a standard of economy may be employed. I ordinarily employ kraft papers because of their availability and cheapness. The thickness of the webs may be considerably varied, and I ordinarily employ papers of between 15 1b. and 60 lb. basis weight.

It is important to bring the papers themselves into as intimate an association as possible with the surface of the discrete bituminous layer. Hence, I prefer to employ papers creped with relatively fine and uniform creping crinkles as distinguished from papers of corrugated,

pleated or folded types wherein substantial areas of the f paper webs might be out of contact with the bituminous layer. Fine and uniform creping crinkles, even with heavy papers, can be attained by creping the papers by means of a positive creping adhesive. This adhesive may be the bitumen used for the discrete waterproofing layer in my roongs or it may be some other substance capable of forming a good bond therewith and chosen for additional characteristics.

The exposed paper webs do not require to be waterproofed throughout their body since even plain paper webs directly exposed to the weather in my products exhibit a long-term water resistance, as set forth above. But the durability of the paper webs may be increased and the tendency to shrink may be decreased by saturating or coating them with protective substances of bituminous, waxy, resinous, rubbery or other characteristics, and this may be done prior to or as an incident of the creping operation.

In Figure l, I have illustrated a rooting fabric which, insofar as it embodies a base of saturated felt 1, and a heavy discrete layer of bituminous coating 2, is similar to the prepared roongs of commerce. This product has, however, been treated by imposing upon the outer surface of the bituminous layer 2 a layer 3 which is a universally stretchable. gathered web, as set forth above. The addition of such a web has been found to add years of service to the product in the ways already described. The web 3 is the portion of the product directlv exposed to the weather. It mav, as indicated, be of untreated paper throughout its thickness. but it may if desired be waterproofed or saturated or colored or treated on the exposed surface with a coating of paint or lacquer or suitable binder containing metallic flakes, as in aluminum paint. Y

It has been found that the addition of such a laver protects the bituminous laver 2 from the progressive destruction which has been described. Contrary to expectations. the web 3 does not tend to expand by itself upon standing or weathering. On the contrary. it tends to maintain itself under slight tension. and if the roofing is exposed to weathering, including high temperatures, a tendency of the web 3 to pull slightly inwardlv from cut edges of the product mav be observed. There is no tendency, however. toward delamination providing the pitumisnous layer 2 is well-bonded to the stretchable ayer The product illustrated in Figure 1 may be manufactured and sold in roll form or in the form of cut individual units. In smaller units. such as shingles or shingle strips, or even at the edges of roll rooting units. T may destroy the tendency of the web 3 to pull inwardlv and also protect the edge of the felt by a method illustrated in Figure 2 where a stretchable web 3. larger in dimensions than the remainder of the rooting unit comprising the saturated felt 1 and the bituminous layer 2 has been employed, and where the extending edge of the web 3 has been brought around the edge of the roofing unit 6 and cemented back underneath, as at 3a. The cementing process. If the paper is creped so as to acquire 25% may be done with bitumen or with any other waterstretchablity in each direction, 57% is added to the proof adhesive capable of making a good bond. weight or thickness of the initial bituminous coating.

In Figure 3 I have shown a piece of rooting material Similarly, if the paper is creped so as to acquire 33Va% manufactured entirely from a plurality of stretchable 5 stretchability in each direction, 77% will be added to the webs and a plurality of discrete, heavy layers of bitumen. weight or thickness of the coating. These factors may The illustrated product comprises four layers of creped be taken into account in applying the initial coating of paper 4, 5, 6 and 7, and three layers 8, 9 and 10 of bitumen to the paper. Again, the thickness of the coatcoating type bitumen. The product may, however, be ing between layers of creped paper will, of course, be made of three layers of paper and two intermediate layers 10 doubled if the creped paper layers are plied with their of bitumen, or with a larger number of layers as may coated sides next each other. In manufacturing products be desired. such as are shown in Figure 3, I ordinarily form two In a product such as is illustrated in Figure 1, the layers of coated paper and adhesively secure them tosaturated felt 1 serves to provide a base or support for gether with the coated sides in contact. The resultant the bitumen, but is itself deficient in weather resistance. product will be of suflicient strength and resistance to Moreover, the exemplary product has but one layer of stretching to permit the application of a heavy coating bitumen which can serve as a waterproofing membrane, of asphalt for the reception of additional layers of coated although it may be made with more by plying. By concreped paper. In making a 4-ply product, I may iirst trast the product of Figure 3 contains in the illustrated manufacture two 2-ply products, coat each and ply themembodiment three discrete heavy layers of bitumen servtogether with their coated sides in contact.

ing as waterproofing membranes and providing a greatly In the application of built-up rooiings, my products prolonged life. The use of a plurality of layers of bitupresent further advantages and economies. It will be men and intermediate and external layers of stretchable understood that the efcacy of a built-up roof if properly paper provides in itself a structure having suilicient body laid will depend upon the number of continuous waterand strength for roofing uses, yet containing a plurality proofing membranes which it contains. Since the upper of bituminous layers capable of serving as a water and or surface membrane is subject to the distintegration weatherproof membrane. which I have described, and since the saturated felt is Certain other advantages are secured in such a prodnot itself satisfactorily weather resistant, it is the general uct. The uSe of stretchable Webs on both Sides provides practice to cover all portions 0f a roof deck with a plu-' a product which not only is reversible in that it may be rality of layers of saturated felt, and intermediate layers laid either side up, but also will not stick when wound plus a top layer of mopped asphalt. The mopping of into rolls. The use 0f tale 0r other material fOr prelayers of felt onto a roof deck and onto each other is an venting adhesion iS 0bviaied The PrOduCt, mOIeOVer, 1S arduous and inconvenient task, the results of which are as a whole more exible than a prepared roofing of the greatly affected by the skill of the workman and weather same thickness and conventional construction. conditions. Moreover, the result may be made unsatis- This makes it possible fOr me t0 effect a Seam c0nfactory by overheating the asphalt in the kettle whereby struction aS hereinafter S'et forth. The Surfacing and its weather resistance may be impaired and by failing to intermediate layers of universally stretchable paper are apply the felt layer to a mopped-0n coating at a time effective in Preventing Cracking 0f the product when it when the asphait is sufficiently tacky to form a good is belli sharply al all auglewhen laid UPOn a 100f and 40 bond. Blisters in built-up roofs are not uncommon.

fastened at both edgss 1l {naintains itself bodily unlel In laying a builtp roof from a product such as illusslight tension which keeps it. taut and prevents buckling trated in Figure 3, it may be noted that the product alor stretching. Yet the tenSlOn 1S S0 Slight that 1t Will ready contains a plurality of bituminous membranes. 110i Pull aWaY from fasienlngmeans such as roofing Halls, These were formed at the factory under conditions of nor will it pull itself into WrlnkleS- Y careful temperature control. They will be more uniform It has further been found that if the :external layer and more dependable than membranes formed by mopof bitumen in a product Such aS Shown in Figure 3 beping on the job. Because of the plurality of membranes comes, through the removal or destruction of the eX- built into my product, the laying of a built-up roof is posed layer 4 of stretchable paper, subject to progressive simplified. Fewer layers and fewer moppings will be disintegration Characteristic 0f heavy bituminous layers, 50 employed, and it is usually suicient to use a single layer this disintegration will stop as soon aslit reaches an of a product of suitable thickness. Thus n Figure 6 I underlying layer of stretchable paper, again very greatly have shown adjacent pieces 12 and 13 of my product prolonging the life of the product. mopped onto a concrete deck 14 with a suitable cemented While there is no tendency toward delamination in lap as at 15. It will be understood that on a wood deck the product, the Same phenomenon 0f the Slight pulling 55 fastening means, such as nails, will be employed to hold back of the upper paper layer 4 at the edges of the prodan edge of one piece which edge including the fastening uct may be encountered and can be corrected in a similar means will then be lapped by an edge of the adjacent way. In Figure 4 I have shown the product where the piece. A,

upper paper layer 4 has been caused tofextend beyond 'It will not be necessary to provide my built-up roof a cut edge and has been folded over, brought back bewith a top mopping of bitumen. If, however, the roof neath the product, as at 4a, and adhesively secured as is to sustain tratlic,:it may be desired to top mop it, as at before. Yet another way of treating the edges of the 16 in Figure 6, and to provide it with a covering of product is shown in Figure 5 where an edge portion theregranular material, as at 1' 7. This may be done without of has been bodily bent back upon itself.l and adhesively detriment to the roof or its weather resistance.

secured at 11. This is a treatment which may be used The extraordinary flexibility of my products such as both for roll rooting and for individual units such as shown in Figmre V13 makes possible the formation of shingles which may if desired be rolled or turned on all various types of adhesively united seams. In Figure 8 exposed edges, it being unnecessary to do this at the end I have shown at 18 a p iece of my fab'ric prepared for of the product which will be lapped by other shingles seam formation. The sid e of the fabric shown is that or units. The turned edges may merely be adhesively which will be the under .side in use. Along one edge I secured or they can if desired be held by any suitable provide a band 19 of suitable waterproof adhesive mafastening means such as rivets, staples, or the like. terial. This material may b e a pressure-sensitive, sol- In manufacturing a product such as illustrated in Figvent-sensitive or thermoplastic adhesive of waterproof ures 3 to 5, I prefer to crepe the paper by means of the nature. Asphalt is an entirely satisfactory. material. bitumen to be used as the waterproofing membrane. I When used, it may be applied hot and'immediately covhave given above thicknesses of bitumen capable of servered with a strip 29 of cellophane .or similar material. ing as the discrete heavy layers contemplated by this It is characteristic of this combination that the celloinvention. In accordance with the teachings of my Patphane or similar non-fibrous ilm may readily be removed ent No. 1,782,767, dated November 25, 1930, entitled from the band of adhesive by a quick jerkingmovement, Creping Process, it is not diicult to crepe papers bearalthough with a suitably tenacious asphalt, it is not capaing asphaltic or other bituminous layers of the required ble of being readily peeled away. It may be removed by thicknesses. It will be understood however that coatings peeling if it its iirst wet with water. Removal by a jerkf r cre in are usuall im osed u on the lain paper; ing movemen is mos convenien hcence tihe gthickness of] thepcoatingp'is incregsed by the At the other edge of the fabric 18, I p rovide another amount of gathering imparted to the paper in the creping band of similar adhesive but of lesser width, as at 21.

This is also covered with a strip 22 of cellophane or the like. Inwardly of the edges of the adhesive bands 19 and 21, I prefer -to score the material `to facilitate bending.

The material of Figure 8 maybe made continuously asindicated in Figure 7. Here the material, moving in a direction of the arrow, is first passed between rotary scoring devices 23 and 24, and is next coated with the adhesive. This maybe done by providing a pan 25 of asphalt or other suitable material (together with heating means as may be required), an applicator roll 26 and a series of transfer rolls 27. An anvil roll 28 may be employed to support the fabric during the coating.

Coating may be applied to form the strips 19 and 21 in other ways. By way of example, it is within the scope of my invention to spray onto the surface of the fabric 18 a heat softened bitumen or other adhesive, or to apply by spraying an artificial latex or dispersion of such material. The cover strips, one of which is indicated at 22 at Figure 7, are withdrawn from rolls as at 29 and applied by squeeze rolls 30 and 31. The product treated in this fashion may be wound into suitable rolls for shipment.

In laying the product, theside to which the adhesive has been applied is disposeddownwardly, but the edges are turned up on the score lines and the cover strips 20 and 22 are removed. In Figure 9 I have shown two adjacent pieces of roofing at 32 and 33. The edge portions areturned up as at 34 and 35 and are brought together with their coated sides in contact. A completely tight seam may be formed between these juxtaposed edges' by pressing them together, with an application of heat if required to reactivate the adhesive, or with an application of solvent. The pressing may be done by rollers 36 and 37 mounted on pivoted arms 38 and 39 by which the rollers may be pressed strongly together and by which they may be moved along the seam. It will be noted as an advantage of this procedure that the edges of the fabric are pressed directly together and thus are brought into positive contact. This is to be distinguished from an operation in which the edges of roofing fabric are merely lapped and are pressed against a roof deck. In such an operation inequalities in the roof deck may relieve the pressure over certain areas, interfering with full contact.

After a seam has been made as illustrated to the right in Figure 9, the entire standing portion of the fabric may be laid over as shown at the left-hand end of the ligure. Because the portion 34 of the fabric is narrower than the portion 35, it will be seen that a coated edge of the fabric piece projects freely and may be used to fasten the laid-over seam construction against the fabric piece 32. Adhesion may be effected by running a pressure roller 40 along the edge of the seam formation, out the application of heator solvent as may be required.

lwith or with- Prior to the laying over of the standing seam construction, the marginal portions of the fabric piece 32 may be fastened to the roof deck, if ofv wood, as by fastening nails or the like 41 in Figure 10.

The fabric 18 may be prepared with covered lines of adhesive for the formation of other types of seams as will now be evident.

Modifications may be made in my invention without departing from the spirit of it. Having thus described my invention in certain exemplary embodiments, what I claim as new and desire to secure by Letters Patent is:

1. A prepared roofing fabric consisting lof a plurality of heavy, continuous, discrete layers of `bituminous substance, each capable of serving as a waterproof membrane, and each having a weight of not less than about 8 to 10 pounds per sq. ft., said layers being separated from each other by universally stretchable creped webs of paper 1n intimateladhesive association therewith, there being layers of universally stretchable crepe paper forming the outer surfaces of the fabric, and means for the formation of 'seam structures in adjacent fabric pieces, said means comprising a coating of adhesive substance on a marginal portion of the rooting fabric, said coating being covered by a removable protective strip.

2. The structure claimed in claim 1 wherein the fabric is scored for bending along a line adjacent to the edge of said coating.

3. The structure claimed in claim 1 wherein the fabric is scored for bending along a line adjacent to the edge of said coating, and in which said adhesive comprises bitumen, and said covering is a removable strip of nontibrous film substance.

4. T he structure claimed in claim 1 prepared for seam formation and bearing strips of adhesive adjacent oppo- `site marginal edges of the reverse face of the fabric, said strips being of unequal width.

References Cited-in the le of this patent UNITED STATES PATENTS

Claims (1)

1. A PREPARED ROOFING FABRIC CONSISTING OF A PLURALITY OF HEAVY, CONTINUOUS, DISCRETE LAYERS OF BITUMINOUS SUBSTANCE, EACH CAPABLE OF SERVING AS A WATERPROOF MEMBRANE, AND EACH HAVING A WEIGHT OF NOT LESS THAN ABOUT 8 TO 10 POUNDS PER 100 SQ. FT., SAID LAYERS BEING SEPARATED FROM EACH OTHER BY UNIVERSALLY STRETCHABLE CREPED WEBS OF PAPER IN INTIMATE ADHESIVE ASSOCIATION THEREWITH, THERE BEING LAYERS OF UNIVERSALLY STRETCHABLE CREPE PAPER FORMING THE OUTER SURFACES OF THE FABRIC, AND MEANS FOR THE FORMATION OF SEAM STRUCTURES IN ADJACENT FABRIC PIECES, SAID MEANS COMPRISING A COATING OF ADHESIVE SUBSTANCE ON A MARGINAL PORTION OF THE ROOFING FABRIC, SAID COATING BEING COVERED BY A REMOVABLE PROTECTIVE STRIP.

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