US1612776A - Roofing element - Google Patents

Description

, Dec. 28, 1926.

L. KIRSCHBRAUN ROOFING ELEMENT Filed August 24, 192:

7620@ l a ja'mzfzaa leo/:3677

Patented Dec. 28, 1926.

@Nrrsn .STATES imm PATENT OFFICE.

LESTER KIRSCHBRAUN, F LEONIA, NEW JERSEY, ASSIGNOR T0 THE FLINTKOTE COM- PANY, OF BOSTON', MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

RooING ELEMENT.

Application filed August 24, 1925. Serial No. 51,949.

This invention relates to the production of roofing elements generally of the character of shingles, slabs, shingle strips, clap-4 board or the like, in which, when the material is laid upon the roof in overlapping courses, there are exposed marginal portions with edges that are subject to deterioration caused by the sunlight and the elements.

Ordinarily, in the manufacture of modern roofing such as employed for these purposes, it is lthe custom first to forma sheet of felt which is made ordinarily of rag fibers or rag and asbestos -fibers or'the like, of the desiredV caliper and of sufficient porosity to permit it to absorb a molten water-proofing composition such as pitch, asphalt or the like,and of sufiicientv strength to enable it to be manipulated during the operations of 'forming the ultimate roofing product. This is a commony article of commerce which is ordinarily known as roofing felt and is produced on the usual paper-making machines. After the sheet has been properly saturated with the bituminous saturating "compound, either by immersion in a bath of a molten bitumen or pitch, or by subjection to pressure saturatlon, the sheet is coated on one face with a fairly thin layer of high melting point asphalt. For this purpose, oxidized or blown asphalt so-called is preferably employed because of its tough and rubbery-nature. While the asphaltic coating is still soft and plastic and before it has set, it is surfaced with any suitable form of crushed mineral such asV crushed slate, tile or any other mineral grit which will impart the desired color and texture to the final product.-

The grit is preferably formed in relatively large particles or' granules which Vary -in form according to the material from which they are produced. The surface minera coating is partially embedded in the plastic asphaltic coating sufliciently to insure afirm interlocking of the granules with the asphaltic coating, but leaving thegranules Iso expcsed that the asphaltic layer' is completely covered and masked by the particles or grains of grit. In ordinary practice the shegtthus formed is now cut, into yroofing elements, which take vthe form of individual shinglesor strip shingles or slabs yof various designs or in long narrow strips'which may be employed for the sides of buildings in the same manner as wooden clapbo'ards.

The operation of the cutting machinery )is such that, when .these roofing elements are -asphalt with a consequent checking or break: ing down of the asphalt particularly when it is exposed in relatively thin films-or layers. This is especially true -of the asphalt or other bitumen whlch is utilized as thev saturating compound for the `foundation felt, inasmuch as the films of asphalt about the fibers of the felt are relatively thin. Due

to the action of the light and of moisture, A

these films crumble; and this, together with theA absorption of moisture by the exposed fibers, causes the breaking down of the exposed-edges and produces a tendency on the part of the exposed margin of the roofing element to curl. The curlin isdoubtless al; so' accelerated by the fact t at the layer of coating asphalt contractsunder the'influence of the elements and the rays of the sun and because of oxidationl to a greaterl extent than the saturated felt itself. l l

vOn the other hand, a single layer of as phalt which is too thick is liable to crack through from internal stresses set yu by unequal heating and-cooling, especial y in winter Weather when the asphalt is comparatively hard and brittle. Cracks thus vformed in a coating of asphalt'admit moisl ture to the fibrous-foundation'of the elelproofing with a single coating of blown asphalt, such coating should be from .040 to .070`0f an inch thick. The grit surfacing material usually "applied to such a coat# ing often comprises particles large enough to extend all the way through the coating and puncture it. If-these particles are dis" i lodged in the subsequent treatment andfl'm handling of the roofing, they leave small pinholes in the coating, through which moisture can enter. While these breaks in the continuity of the surface coat are not as serious a cause of deterioration of the element as are the cut exposed edges, yet their tendency is in the same direction, namely, to shorten the life of the element.

In the practical production of the roofing elements herein referred to, it is customary to apply the grit surface layer to only one face of the product, a portion of which is to be exposed to the weather, and in most cases the under face of the roofing elements consists of merely the saturated felt. In

v some instances it is true that a thin layer of the asphaltic coating is applied to the under face of the roofing element when the sheet is being saturated and coated. When the elements are laid in overlapping courses, however, Water finds its way under the exposed edges and margins of the elements, either by capillary action or by the beating rain with the assistance of the wind, and in winter weather this moisture freezes and thaws and has the effect of lifting the exposed edges of the roofing elements from contact with the" are rapidly attacked and their efficiency de.

stroyed.

The problem which thus presents' itself is to find some way of preventing or overcoming the deterioration at the cut edges of the roofing material and of prolonging the effcctive life of such rooting' elements. In attacking this problem, one is confronted with the fact that the saturated felt is the weakest component of the roofing product. so far as its liability to deterioration is concerned. 'I'he cellulosic fibers of which it is formed have an aiiinity for moisture, and the saturated felt itself ordinarily will absorb moisture up to 20% of,its weight. Yet the integrity and the strength of the roofing product are directly dependent upon the integrity and strength of the saturated felt, for if this be destroyed the product as a whole loses its waterproofing and durable characteristics. The deterioration of the saturated felt is evidenced by progressive loss of cohesiveness and structural strength, sothat the resistance of the final product to the weaving of the roof structure and its flexing through the action' of the winds and the elements becomes insufficient to maintain it in place.

lIn seeking an answer to the problem,

therefore, means must be provided for the maximum protection of the saturated lfelt to prevent access of moisturefoxygen and light thereto. This is accomplished by providing what may be termed a supplemental coating of high` melting point asphalt, preferably blown asphalt, in a layer of sufficient thickness so as completely to seal the fibers of the -felt with ank impermeable envelope so as to prevent the access of air or moisture;V

ized for this purpose, but as a practical matter one may employ crushed slate, crushed tile, or any other opaque granular material which may be partially embedded in the asphaltie layer in such manner as completelyv to cover it and to prevent the access of the rays of the sun directly thereto to any substantial extent.

The present invention comprises an individual roofing element in the nature of a shingle, shingle slab or strip, having the exposed edges sealed by an enclosing envelope of asphalt or bitumen and the envelope itself is protected against light by a surface layer of an opaque material preferably applied in granular form.

Incidentally, however, I have found that it is possible to produce a roofing material which is superior to those heretofore made of flat sheets, in. that the element may be so formedv that it is gradually thickened towardswhat may be called the butt or exposed end thereof. Thus, when the rooting elements are laid in overlapping courses, the roof thus formed has the appearance of and has an actual degree of thickness which imparts a pleasing effect and which relieves such roofs from the monotony and flatness that have characterized roofs formed of fiat elements.

A roofing element thus formed possesses certain-other highly desirable characteristics which are lacking in the ordinary flat element as heretofore produced. First, by reason `of the fact that the element is thickest at the butt or exposed edge thereof, its weight is greatest at the edge and colisequently the` exposed edge oii'ers greater resistance to the lifting force of the wind and will remain flat when the fiat elements of unvarying thickness would be lifted or raised by the winds pressure. This also permits ot' greater area' of exposure. JAgain, inasmuch as both'faces (that is, the' upper and the lower faces) of the element are coated to substantially the saine extent by the asphaltic envelope, there is no tendency for the exposed portion of the element to curl away fronit-he element overlapped thereby. As` plialt, when exposed to light and the elements, tends to contract g' and, where the roofing element has no or only a thin layer.

of asphalt on its under side and a relatively therethrough byl particlesof grit or in any other Way, and although the second coating infiltrates between thegparticles of grit and bonds With the rsthcoating, the grit layer maintains 'the separatfef'identity of the two coatings and .prevents the lcracking stresses which would ordinarily be set up by thermal changes in av single layer lof coating material of a thickness equal to the sum of the two coatings. s f f In the 'productiongof such elements as .herein described, one may start with the yordinary roofing' elemen s of' commerce, namely, individual single shingles, strip shingles Iorslabs, or clapboard slabs, all of .which are designed tobe laid in overlapping `courses with what may be termed for convenience exposed butt portions. `These butt portions aredipped into a bath of molten asphalt for a sufficient time to cause them to be covered on both faces and on their exposed edges with a fairly 'thick layer of asphalt. By reference to Figures 3, 5 and 6 of the drawing, it Will'beseen that the coating around the butt edge of the shingle is roiinded'and of a substantial thickness.

This is for the purpose of providing a surface free of sharp corners and'with suflicient coating over the corners of the foundation vto retain firnily'grit-whicli is 'thereafter applied. Furthermore, this enlarged rounded surface gives the shingle a very pleasing appearance. On removing the ele- 'nients from the asphaltic bath, theyare per- This processl for treating pre-cut strip jections@ and intervening' notches c, 0.

practically eliminates the waste due te factory seconds, that is, finished elements which have slight defects which impair their salability and greatly reduce their value. rlhe disposition of such elements has been a difficult problem involving considerable loss to manufacturers. By my invention, sec- Onds7 can be reclaimed by the provision of the refinishing enveloping coat of asphalt and grit, and thus be made not only into a salable product, but one which is more durable and more effectiveand ornamental as a roof covering than the ordinary grit-sun faced shingles. y

On the accompanying drawing I have illustrated a strip shingle embodying the invention, but` it will be understood that the invention may equally Well be incorporated or embodied in an individual single shingle, or an individual clapboard strip.

Fig. 1 represents a shingle strip as ordinarily formed, and which in the present iiistance serves as'the starting material of my product; Y f

Fig. 2 represents the completed product;

Fig. .3 represents a section on the 'line 3 3 of Fig. 2;

Fig. 4'represents an enlarged section on line 4 4 of apart of the strip shingle;

Figs. v5 and 6 illustrate the formation of a double-dipped shingle.

Referring to the drawing, I have shown in Fig. l, at a. what is commercially known as a slate surfaced square butt strip shingle, which is provided at b, b 'With tabs orsproi uci a shingle is usually laid with others in overlapping courses, so that the butts of the tabs register with the upper ends-of the notches of the ystrips overlaid thereby. The tabs may, for example, be four inches in length, ywhere the entire strip is ten inches' between its upper and lower edges.l Of course it will be understood that the design of the strip shingle may be varied,- so that thetabs'may be semi-hexagonal, or semi-octagonal, or of 1^ ,any other desired shape.

Thesliingle strip, as shown, has a base of rag or asbestos felt 10Which is iii'ipregnated with asphalt or oth'ercominonly used waterproofing compound, -a layer- 1l of higher melting point aspha1t,- an d a si'frface layer 12 of granular material. y Y

The strip is held by its straightupper asphalt, which is l preferablv oxidized or blown asphalthaving a melting. oint of 2200-240 F'. The dipping operat o n must be carried'on While tliemolten'asphalt-fis at an elevated temperature, and is so tijmedthaft the strip Will pick up the proper amountnof edge, and'isgdipped, into a bath of molten asphalt and also readily free itself of the excess. If a heavy. coating is desired, the temperature of the bath is lower than when a thinner coating is to be applied. I have found that the desirable temperature to roduce the optimum viscosity of the aspha t is in the range of 4250-4500 F'. when using oxidized asphalt from Mexican stock. It will be appreciated that the viscosity of an oxidized asphalt at a given temperature, will vary with the nature of the stock from which it is prepared, as well as its melting point, and the temperature to which it is heated.

"fherefore' the temperature range which I have given is only indicative of the viscosity of the particular stock there referred to. The period in which a part of the shingle strip is dipped in the asphalt must be very short in order` not to melt or unduly heat or soften the underlying bituminous material One or twoV seconds is usu-l the coating 13 on both faces to'flow toward ina chinery.

the lower edge, and vthus form tapered layers which are thickest at the edge, the excess 7 drops being flipped or else wiped off. The

strip is now surfaced with an opaque grit 14 which is caused to become partially embedded in the still plastic asphaltic coating or envelope, not only on the faces of the strip but on all the edges rthereof which are asphalt-coated, and as a consequence there is a continuous layer of exposed grit which extends'over both faces and across all of the lower edges of the strip, including` the edges of the tabs and the edges at the upper ends of the cutouts or notches. This may be done by first pressing the strip flatwise against a thick layer of loosegrit, then rocking the strip through an arc of 180" about its asphalt-coated lower edge as the center, land pressing the other face against the layer of loose grit, and forcing or piling grit into the cut-outs or recesses .and against the end edges of the strip. This molds the asphalt and grit at the lower edge of the strip and Ifurnishesa straight rounded edge which is pleasing in appearance. The strips are piled one on the other, as produced, and the weight of the pile forms flat surfaces on the faces of the strips. 'The operations may, however, be performed by suitable automatic In Fig. 2 of the drawing, I have shown the slate-surfaced strip shingle of Fig. 1,' as

it appears when it has'been subjected to the operations herein describe-d. It will be noted from the sectional view illustrated by Fig. 3, that the shingle strip is thickest at its butt or lower edge, and tapers'upwardly to a line just above the cut-outs or recesses.

In some cases for the opaque granular material, which is employed to cover, protect and mask the asphaltic envelope, I prefer to employ grit or granules of a different color and/or size from those which originally formed the outer layer of the original strip, especially in the case of strip shingles or individual shingles, so that a contrast will be afforded between the exposed portions thereof and the upper portions of the overlapped strips, which are visible through the notches, or through the spaces between the individual shingles. r Again, instead of 'starting withY` a grit-coated rooting element, ashereinbefore described, one may start with a roofing element cut from rubber rooting, so-called,

-which is an asphalt-impregnated' sheet, having layers of high melting point'asphalt on one or both faces thereof. Usually,'but ynot necessarily, such lrubber rooting has a surface layer of talc or mica. y

I should not regard it as a departure from my invention if the protecting asphaltic envelope of the roofing elements were surfaced with pulverized material, or with tale or mica, or if the envelope itself were formed of a colorable pitch such as stearin pitch, or mixtures of resins land tempering huizes,

with a suitable` pigment incorporated there-v .in to impart the desired color thereto.

In instances where it is desired to keep down the weight of the roofing element, the front face and the edges of the strip may7 be surfaced with crushed slate partially embedded in the asphaltic envelope, and the rear face surfaced with a line powder such as talc or mica.

In certain cases where an eXtra thick butt isdcsired on the roofing element, I may subject the element to a series of dipping and grit-surfacing operations.l lIn such case, in the first dipping the eleinent may" be iininersed, say, one and one half to two inches, and after the grit-surfacing operation has been carried out, and the asphaltic coating has set, the element is, in the second dipping immersed to an extent pf tive inches,

after -w-hicl'i it is surfaced, covered and protected with a layer of granules of opaque material.

In Figs. 4, 5 and 6, I have shown a strip which has ,been subjected tothe series of operations last described.

In order to secure certain results, one may surface the edges of the cut-outs or recesses f .of a shingle stripwith lines of the same color as the granules which coat the faces of the strip. Such fines are the powders or dusts which Separate from the'larger granules of Yslate or other,minera.1 grit.

tempra in each of the'rooiing elements herein described, the continuous asphaltic coating which covers the upper and under faces and the bottom and side edges of the exposed or butt portion thereof, is securely interloclred With the usual granular'facing, if there be one, on the upper face of the element, and

more or less coalesces with the asphaltic impregnating compound at the edges and on the underface of said'butt portion. While the period of immersion or dipping is ver'y shortv so as not to melt such impregnating compound and the initial asphaltic coating, yet there is sufiicient heat in the second or continuous coating to cause a sufficient softoning thereof and to cause the necessary coalescence and interlocking of the two. A The Word felted as used in the specification and claims is-intended to distinguish from a naturally formed fibrous structure such as Wood'but, is used with a` Viewpof including any base made from segregated fibres formed into a' sheet, or base yof an equivalent nature, by any suitable machinery.

Having thus explained the nature of my improvements and a mode of producing products'embody'ing the same, what I claim is l. A roofing element adapted' to be laid With others in overlapping courses comprising a felted foundationimpregnated with a waterproofing material, a coa-"ting of asphalt on the exposed face, the butt and side edges and a portion of the under face thereof, and

a surface layer of granular material partially embedded inthe asphalt coating ex, tending over the said exposed andI under face of the element and the butt edges thereof. I'

2. A fiexible roofing element adapted to be laid with others in overlapping courses comprising aA fiexible felted foundation impregnated with a Waterproofing material, a continuous envelope of asphalt encasing the exposed' farce, the butt and side edges 'and af portion ofthe under face thereof, and a surface layer of granular material partially embedded -in the asphalt coating extending over the saidexposed and under face of the element and the butt and side edges thereof. 3. A roofing element adapted to be laid with others in. overlappingI courses `comprising a felted foundation impregnated with a Waterproofing material, a coating of asphalt lon the exposed face, 'butt and side edges and a portion of the under face thereof, a surface layer of ranula-r material partially' embedded in said asphalt coating extending lover the exposed face of the element and the butt and side edges thereof, and a layer of comminuted material partially embedded in the asphalt coating on the under face of said element.Jr 4. A flexible roofing element adapted'to be laid with others injoverlapping courses, comprisingamsaturated flexible fibrous founda-Y tion, a coating of asphalt thereon covering the exposed face ofthe element when laid,

the butt and side edges and a portion-of the a ing of asphalt thereon covering the exposed faces of the element when laid, the butt and side edges and a portion of the under face thereof, said coating extending over the butt edge being substantially rounded and a surface layer of granular material partiallyY embedded in said asphalt coating on the expoi'ed face and side edges of the element and in the rounded coating extending around the butt edge thereof.

6,'A roofing element adapted to be laid with others in'overlapping courses comprising a felt foundation'.impregnated With a bitumen coating of asphalt thereon covering the exposed face of the element When laid, the butt and side edges and a portion of the under'face thereof, said coating being thickcned and rounded about said butt edge, and a surface layer of granular material partially embedded in said asphalt coating on the exposed face and the side edges thereof and in the thickened rounded coating extending around the butt edge thereof.

. v7. An individual roofing element adapted to be laid with others in overlapping courses, comprising a flexible fibrous foundation impregnated With asphalt, and having its upper face thereof coated with asphalt and surfaced with a comminuted material, said element having an yadditional and continu- `ous asphaltic envelope extending over that portion of the upper face o-f the element which is exposed when said element is laid as described, over' the bottom and side edges and over a portion of the under face of said element, whereby all 0f the exposed `portions of said elementare encased, Within a continuous Waterproof coating ,of asphalt and a layer of comminuted mineral embedded in said asphalt coating on the upper exposed face of said element 1 i 8. An individual roofing element adapted to be laid With others in overlapping courses, comprising a flexible felted foundation impregnated with asphalt, and having its upper face thereof coated with asphalt and surfaced With partially embedded grit,'said element having"v van additional and continuand over a portion of the under face of said element, whereby all of the exposed portions of said element are encased Within a continuous Waterproof coating lof asphalt, and a layer of granular material partially embedded in said envelope on the upper face and on the bottom and side edges thereof.

9. An individual roofing element adapted to be laid with others in'overlapping courses, said element comprising the usual grit-surfaced asphalt-coated Waterproof felted foundation, and having in additio'na continuous coating of asphalt superimposed upon the butt portions of the upper and under faces andthe intermediate edge portions thereof, and a layer of granular material partially embedded in and masking said asphaltic coating, said coating of asphalt and layer of granular material being thickest at the butt edge of said element.

l0. An individual roofing elementfadapted to be laid'With others in overlapping courses, said lelement comprising the usual grit-surfaced asphalt-coated Waterproof felted foundation, and having in addition a continuous coating of asphalt superimposed upon the butt portions of the upper and under faces and the intermediate edge portions thereof, and a layer of granular material partially embedded in and masking said asphaltic coating, said coating of asphalt and layer of granular material being' thickest at the 'butt edge -of said element and being rounded about said butt edge.

1l. A shingle strip having a plurality of tabs with intervening recesses and adapted to be laid With others in overlapping courses With the tabs exposed in simulation of shingles or tiles, Said strip comprising an asphalt-i1npregnated fibrous foundation having on its upper face a coating of asphalt with a surface layer of grit partially embedded therein, and alsohaving in addition a continuous external coating of asphalt covering the upper and under faces of the tabs and the side and bottom edges thereof, and an external surface layer of granular material partially embedded in and covering said continuous asphaltic coating, said continuous asphaltic coating and surface layer being thickest at the butt edge of said ele'- ment and tapering toward and terminating at .a line parallel With the top edge and above but adjacent to the upper ends of said recesses. a

In testimony whereof I have affixed my signature.

' LESTER KIRSCHBRAUN.

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