US2316093A - Insulating covering - Google Patents

Description

'April 6,1943. A. D. M NUTT INSULATING COVERING 2 Sheets-Sheet 1 Filed Dec. 5; 1936 INVENTOR TTORNEY Ap 6, 1943. A. D. M NUTT INSULATING COVERING Filed'Dec. 5, 1936 2 Sheets-Sheet 2 INVENTOR Aeflme Aha 5 MCZVl/TZ' Patented Apr. 6, 1943 to Certain-Teed York, N. I, a corporation of Products Corporation, New Maryland Application December 5, 1938, semi No. 114,359

20 Claims.

This invention relates to felts and similar fabrics composed of fibrous materials. The invention especially relates to fibers of mineral origin, and more particularLv to fibers of rock or vitreous origin. 7

By processes which in themselves form no part of the present invention, mineral materials in the form of fibers have been manufactured.-

from rocks of various kinds such as limestone,

dolomite, shale, and mixtures of such rocks, from slag, glass, and other siliceous or vitrifiable materials. The term mineral wool" is generally understood to designate fibers of this character of which specific examples are glass wool, slag wool and rock wool. Fibers obtained by these processes may be of difierent degrees of, fineness and of length, and various grades and qualities may be obtained with respect not only to the fineness and length of fiber but also with respect to the admixture of non-fibrous particles or other foreign materials.

Such mineral wools are commonly used for insulating purposes in mass or bulk. For example masses of such mineral wool may be placed between studs-in partitions for the purpose of providing the desired air cells which, as is well known, aflord themost eifective insulation. Such materials in bulk or mass also are known to have valuable acoustical insulating properties.

The present invention proposes the formation; of a sheet of mineral wool fibers which may be suitable for various purposes for which felted 'thefiber web or for the felted in the felting process as do cellulose or similar common fibers used in ordinary felts. Nevertheless by suitable modification of the ordinary felting or paper making process, for example by providing'an apron or other suitable support for sheet during its travel through the machine or upon'delivery to a subsequent operation or treatment, such as the saturating" operation in roofing manufacture, a felt composed of mineral wool fibers may be prepared and may be handled and treated in the same manufacturing operation as ordinary felts.

To secure a web of sufiicient strength to be handled it may also be advantageous to admix with themineral wool fibers in the process of preparing the fiber for the felting machine or at the point of delivery to the felting machine a certain amount of organic. fibers, such as cellulose fibers or wool fibers, or of natural mineral fibers, such as asbestos. Such an amount of the auxiliary fibrous material is utilized as will not interfere with the advantages gained by the use of mineral wool fibers in a felted sheet, and for the purposes of the invention preferably the felted sheet contains fibers of mineral wool in predominant amount, in order tosecure the open construction which is characteristic of such sheets of various animal and vegetable fibers are now used, particularly for the purpose of providing a base felt, as a substitute for rag felt and for felts of wood fiber or for other felted base materials ordinarily used in the roofing industry.

- According to my invention I propose to prepare a mixture with or a suspension in water of mineral wool, corresponding to the stock prepared in the manufacture of ordinary papers and felts of cellulose or other fiber. I have found that such stock maybe felted as'in the ordinary paper or felt making process. By selection of the proper kind of mineral wool a sheet of the felted fibers may be made from this suspension which will be sufficiently strong to be self-supporting in the felt making process. It also may be so formed as to be adaptable for further treatment in various v processes to which ordinary felts are commonly subjected, including facture.

processes in roofing manu- Possibly because of their smooth or glassy surface and their straightn'ess I have found that mineral wool fibers do not form as strong a web 1 less complet mineral wool fibers in bulk and by which are secured the heat and sound insulating qualities.

By thus forming a felted sheet having an open construction it becomes possible to manufacture weatherproof protective materials, such as sheet roofing, by impregnating the felted sheet of mineral wool fibers with a waterproofing material, such as asphalt or other bituminous impregnating material, in a manner similar to that now practiced in the impregnationv of rag felt or other cellulose base sheets in the roofing 'art. While ordinarily in the roofing art the rag or other felt is first impregnated throughout with a saturant such as asphalt, within the scope of my invention I include not only the more or impregnation or saturation of the mineral wool felted sheet, so that the sheet carries as much of the saturant as possible in accordance with regular roofing practice, but I also intend that the sheet of mineral wool felt of my invention for some purposes may be partially saturated substantially uniformly through fibers and to secure a lighter sheet. for a given thickness. As has been stated above, in the felted sheet the open character of the structure which exists in masses of such mineral wool fibers in bulk may be retained to a substantial degree.

It is a feature of my invention, therefore, that I obtainnot only a weatherproof and water resisting covering material but one which combines with these qualities the characteristics of heat and sound insulation. Such a sheet also, because of the presence therein of the inert noncombusti'ble mineral fiber, is more fire resistant .and less subject to rot and to attack byvermin than ordinary felted sheets composed largely or entirely of organic fiber. Especially in fibrous sheets used as bases [for roofing materials the increased resistance to fire obtained by eliminating the saturant, and having thereon a coating of adhesive usually of bituminousmaterial such as asphalt. Such a saturated and coated sheet would correspond to the so called smooth surfaced roofing especially if, as in common practice, a light surfacing of talc or mica is applied to the adhesive coating. If desired on the other hand, there may be applied to this coating, as in the case of ordinary surfaced roofing, a surfacing of granular material, such as slate, or ceramic, fired or painted granules. Thus the invention provides substantially for the substitution of a base sheet of mineral fibers, especially of the class known as "mineral wool," (for the rag felt or cellulose felt base sheets ofordinary roofing. The various modifications and manipulations as practiced in the roofing industry to secure different roofing products, such as shingles or siding elements, may be carried out with the roofing material of the invention as with the ordinary roofing sheets.

As a further application of the invention I propose the formation of sheet material, for pur-. poses for which ordinary roofing is'used, by applying to a base sheet of felted mineral wool fibers a coating of adhesive, such as asphalt, said base sheet being without the impregnation of the "saturant as in ordinary roofing. Said coating adhering to one surface of the felted sheet may be of such character and thickness as to serve as the waterproofing and weather resisting layer and, if desired, this layer may bind upon the felt a surfacing layer of granular material, :as in slate surfaced roofing or a surfacing layer of mica, talc or fine sand as in "smooth surfaced roofing. On the underface of said felted but unimpregnated sheet a sealing or backing coating may be applied if desired, as in ordinary roofing practice.

In one application of my invention, in order to secure the advantage thereof in connection with ordinary roofing sheets which utilize a felt base of organic fiber, such as rag felt or cellulose fiber felts, I propose to apply to the back of the ordinary roofing sheet a layer of mineral wool fibers. By means of such a layer may be secured in an ordinary roofing product the desired heat and sound insulating qualities as well as improved resistance to fire. The thickness of this layer may be made greater or less to secure greater or less effect of such insulation and resistance within the required limits of cost of manufacture. Broadly within the scope of my invention, 5

this layer of mineral wool fibers may be applied to the back of the roofing sheet in any desired manner. For example, such a, layer may be formed by dropping the fibers on the back side of the roofing sheet, after it has left the coating bath, by first passing the sheet over a reversing roll. If necessary or desirable, after the loose mineral wool has been dropped on or otherwise brought into contact with the back side of the sheet and adheres to the still adhesive coating thereon, it may be pressed by passing the sheet through pressing rolls to secure permanent attachment tothe sheet.

Preferably, however, I apply the layer of mineral wool fibers in the form of a felted sheet of said mineral wool fibers which may be fed parallel tothe feeding of the roofing sheet and may be brought into contact with said roofing sheet directly after it leaves the coating bath which,

in the ordinary roofing process, applies asphalt ordinary roofing sheet, and avoid the necessity of markedly altering the ordinary process of producing such a roofing sheet, while at the same time securing the insulating quality afforded by thelayer of applied mineral wool fibers. In addition, shingle or siding elements or units may be produced which have the virtue of thick butt appearance because of their thickness due to the lamination added to the ordinary sheet and which are made of low weight per unit area. If desired on the other hand, the total thickness of the laminated sheet or the total weight of the sheet per. unit area may bemade the same as that of ordinary roofing.

The waterproofing-capacity of the sheet may be maintained by utilizing the same character and thickness of coating upon the face thereof as in ordinary roofing. In such a laminated product the base sheet. of rag or cellulose fiber, if desired, may be made lighter than in ordinary roofing and the insulating quality, thick butt ap pearance, fire resistance, etc., may be secured by the lamination of the mineral wool fiber sheet. Also within the scope of my invention the base sheet itself may be of mineral wool fiber, felted and impregnated as described above, said roofing product so formed having laminated .thereto on the underside thereof a felted sheet of mineral wool fiber which is not impregnated, in order to secure the insulating and other qualities.

As will be more particularly described in connection wi h the drawings, the lamination or backing sheet of mineral wool fiber' may be applied to the roofing sheet in such a way as to cover only a part of the area of the roofing sheet. This partial coverage may be so placed ,that the mineral woolbacking underlies, in shingle or roofing elements cut from the sheet, that portion thereof which is to be exposed in the assembly of the elements in a roof or a covering construction. In some cases, however, it may be preferable to apply the mineral wool lamination so as to form a backing upon that portion of the element which is to be overlapped by a superimposed element. In some cases also the whole of the element may be backed by sucha lamination. In the last two instances it will be clear that that portion of the element which is next to the supporti g structure will have the mineral wool laminati n adjacent to or in contact with said structure. In some cases this may afi'ord better sound and insulating qualities. The lamination also may be applied upon the upper surface of the element upon that portion thereof which is overlapped by a superimposed course.

In some cases or with some types of mineral wool fibers instead of, or if necessary or desirable,

in addition to the admixture of auxiliary fibers, suchas cellulose or other organic fibers or of asbestos for the purpose of increasing the strength of the felted web during the felting process or thereafter, I may incorporate, either in the preparatory process or at the delivery end of the felting machine, a binder or sizing material; such as silicate of soda, latex, casein, emulsified asphalt or other materials, which will not interfere with the felting process and which will be of assistance in holding the fibers together until the felting is complete and also thereafter during mechanical handling of the sheet. Such binders or sizing materials may be used in such quantity as to be effective for the purpose without interfering with the open structure of the felted mineral wool which is a feature of the present invention and useful for the purposeof securing light weight and sound and heat insulation and fire resistance.

In some cases it may be desirable to form in the felting machine, such as a paper machine, a felted web having two or more laminations which laminations may be felted together in the felting process or may be adhesively bound to gether by a suitable adhesive or sizing material such as is mentioned above. 'Moreover, within the scope of the invention, the composition of the twolaminations may be different, one being so formed in'the preparatory process that it will felt to form a relatively strong sheet'but one capable of being saturated in the manner of ordinary roofing felts, and the other with more open structure providing good insulating quality, As an example of such a laminated sheet may be mentioned a sheet or web of felted mineral wool fibers bound to or carried by a web of felted cellulose fibers or to a sheet of rag felt. For the carrying web of cellulose fibers may be substituted, however, a web of mineral. wool fibers felted or prepared, as described above, so

as to provide the desired strength and, as well, the capacity for saturation with asphalt or similar saturant.

The invention will be further described inconnection with the drawings inwhich Fig. 1 represents a back view of a shingle strip embodying the invention.

Fig. 2 is a section on line 2--2 of Fig. 1.

Fig. 3 shows in section an assembly of the shingle strips of Fig. 1.

Fig, 4 is an individual shingle showing a modified embodiment of the invention.

Fig. 5 shows in section an assembly of the elements of Fig. 4.

Fig. 6 shows in section a further bodiment of the invention.

Fig. 7 shows a section similar to Fig. 2 but of modified em modified form.

Fig. 8 shows a cross-section of a tank for carrying out the process of the invention.

In Fig. 1 the element i is in the form of a shingle strip having cut-outs 3 between tabs 4 and this figure shows a view of the under side of such a shingle having applied to the tab portions assembly of such elements.

thereof a layer I of felt of mineral wool of the type described above. Such a shingle, as may beseen from Fig. 2 consists of a base 8 of satu rated felt, as in ordinary roofing. having thereon a coating I providing the weather resisting layer and serving to bind to itself and the shingle a surfacing layer Ill upon the outer face of the tabs 4 in the 'usual manner. Upon the underside of the shingle is applied a seal or backing coating H of asphalt. Laminated to the shingle upon the underside thereof, either by the adhesive action of the coating II or by applied adhesive or by other suitable means, is

shingle, this shingle being raised from the underlying shingle because of the intervening felt layer, and the overlapped portion of said underlying shingle is closed off. While this is the preferable construction with shingles of the type shown in Figs. 1 and 2. any desired portion of the tab may be covered. For example, the portion of the tab adjacent to the edge 5 thereof only may have applied thereto the felt lamination so as to raise the edge of the shingle and present a greater thickness thereof in the assembly. On the other hand, if desired, the entire underside of the shingle I may be covered by the felt lamination, as shown in Figure 7. When the tab portion, in the manner illustrated in Fig. 1, is covered with the felt lamination not only is a thicker butt end secured but the upper edge 1 of the shingle and the overlapped portion thereof, for the most part, are left in the ordinary thickness and thus in the assembly of overlapping elements or shingles the effect of tapered shingle is secured in the roof as may be seen from Fig. 3.

In Fig. 4 is shown as a modification of the invention a backview of a roofing element of the type known as an "Individual shingle. In the element l5 of Fig. 4 the lower portion l6 thereof represents the part which is to be exposed in the overlapping arrangement in an At the upper part I! ofthe element is provided an offset i8 which acts as a spacing means in order that shingles laid adjacent in a course may become positioned in the course with the portions l5 thereof sepa rated in the manner of ordinary wood shingles. Upon the upper portion ll of shingle i5 is applied a backing layer or lamination 20. This layer, as described in connection with Fig. 1, may be applied to the shingle i5 by causing it to adhere to the coating carried by the base of the shingle or by other means. Fig. 4 also may nation 20 being applied upon the underside of the shingle, such shingles may be assembled in overlapping arrangement in the manner illustrated in'Flg. 5. The felt laminations are then exposed upon the underside of the assembly of shingles and may be in contact with the sup porting structure. For some purposes, such as sound absorption, this may be a preferable COD. struction. It also will be understood that if Fig. 4 is taken to represent the upper side of the shingle, the lamination 2. then representing a lamination applied to the upper face, this lamination in the assembly of elements would become sandwiched between two shingles or elements in.

the overlapping arrangement. For some purposes, such as the prevention of conduction of transverse to the coursewise dimension of the shingle or covering elements such that the laminating layers of felt will be in overlapped relation in the different courses or may only extend substantially to a common meeting line as illustrated in Fig. 5. Any such variations in the dimensions of the applied laminations come within the scope of the invention by which is secured the above described advantages of the open structure of the mineral wool felt lamination.

As.v shown in Fig. 6 in addition to the layer ID of granular material bound upon the base a by the coating 9, by processes well known in the art a second layer of surfacing material may be bound upon the portion to be exposed of the element or shingle by a second layer 21 of asphalt or other adhesive coating; The layer 25 and the coating 21 may extend over the edge of the shingle to cover the surface of said edge which is transverse to the exposed face of'the shingle. The asphalt coating 21 thus may seal the transverse edge surface of the shingle and may extend somewhat around upon the underside of the mineral wool felt lamination 8 applied to the underside of the shingle. Thus not only is the edge surface of the ordinary shingle sealed in the manner in which it has been heretofore accomplished but the ed e of the applied lamination of mineral wool felt also is sealed and in addition such a marginal portion of the underface of said felt lamination as will prevent the absorption of moisture and water by said felt lamination as it lies in contact with the shingle of a subiacent course. The sealed edge surfaces. therefore, and particularly from the standpoint of the invention, the edge surface of the laminating layer not only are capable of resisting the absorption of moisture and the action of the weather but the thick butt appearance is enhanced by the extra coating layer and the surfacing layer and particularly by that portion of these layers which extend around upon the underface of the felt lamination.

While the invention has been described in its embodiment which utilizes mineral wool in connection with ordinary roofing materials and shingle or siding elements, and particularly mineral wool fibers in felted sheet form as applied or laminating layers upon said ordinary roofing sheets and elements, this phase of the invention is not limited to layers or laminations of mineral wool fibers. Within the scope of the invention is included the application of common fibers of organic origin, usually vegetable or animal fibers. as a layer or lamination upon the ordinary roofing sheet or the shingle or siding element. These layers or laminations may be applied in the various positions and relations upon the shingle or siding elements which have been typically illustrated and described above. While woven fabric layers, more particularly of vegetable fibers have been used as backing sheets for felted and saturated weather-resisting sheets, I am not aware that heretofore it has been proposed to apply to a weather-resisting sheet. such as a sheet of roofing, a layer of fibers applied so as to provide in the layer an open arrangement of the fibers so as to be capable of affording heat or sound insulation or capable of adding to the fire-resisting capacity of the weatherresisting sheet.

In order to prevent rotting of such organic fibers or other -deterioration thereof or attack by vermin, preferably such organic fibers are treated with preservatives or germicides such as creosote, bichloride of mercury, or in some cases with asphaltic or bituminous materials. In all cases, however, to accomplish the purpose of the invention such treatment is so carried out that the fibers as they are applied to-the roofing material may be left with an open structure of the layer or lamination and preferably as a felted layer or lamination.

In the claims the words "dry felt" or "d y web" have been used to designate a web or layer of fibers which is not thoroughly impregnated with a saturant, such as asphalt. Although such a "dry" felt or layer may, as described above, have certain sizing or binding materials therein to increase the strength of the layer or web, nevertheless the term "d y" is intended to indicate a fibrous layer or felted web in which the open structure thereof is substantially that which would be obtained without such sizing or binding materials. While a "saturated web may. as in ordinary roofing practice, be capable of absorbing water or other liquid less viscous than asphalt or similar saturants, the degree of openness of the structure of such a saturated layer of fibers or felted web is markedly reduced with respect to a layer or web which may be designated as a "dry layer or web.

I In order to apply the coating 21 upon shingles of the form shown in Figure 6 described above, I propose a method which will insure the application of this coating upon the face of the shingle which is to be exposed upon the roof. but will prevent the application of the coating to the mineral wool lamination 6 applied to the underside of the shingle. This method comprises the step of placing two shingles of similar dimension with the lamination 6 in contact with each other, that is with the shingles back to back. This leaves the surfaces of the shingles to which the coating 21 is to be applied exposed upon this assembly of two shingles, so that this assembly may be dipped in a bath of asphalt in the manner illustrated in Figure 8 in which is. shown a tank 30 containing the bath 32 of asphalt or other coating material. Supported by suitable means attached to the walls of the tank 30 so as to be submerged in the bath of asphalt is a shelf 34 upon which the edges of the pair of shingles may rest as they are dipped together into the bath. The level of the bath of asphalt may be kept at such a distance above the upper surface of the shelf 34 that the width of the coating in the direction transverse to the lower edge of the shingle may be de ermin d by bringing the lower edges of the pair of shingles into contact with shelf 34.

In order to keep the shingles together so that the lower edges thereof do not separate and permit the asphalt to run up between the two shingles, clips 35 may be attached to'the shelf 84. These clips It may be formed to bear against the shingles as they are set down upon the shelf 3|, thus maintaining the back faces of the shingles in contact. Application of the coating of-asphalt upon the mineral wool felt 8 thus is prevented. Nevertheless, the lower edges of both shingles are coated, including the lower edge of the mineral wool felt on both shingles. As such felt is quite absorbent by capillary action it will draw a slight amount of the asphalt up through the edge surface thereof but the coating substantially remains applied to and covers both the lower-edges of the shingles and the lower edges of the mineral wool felts and tends to also cover only a narrow marginal portion of the back faces of this mineral wool felt 8, as illustrated in Figure 6.

Instead of. or in addition to, the clips 35 held by the shelf 34, I may fasten the two shingles together by removable clips or by other mechanical means before dipping in the bath 32. I also may tack these shingles together with adhesive applied at points along the matched edges of the two shingles. Such'means for holding the shingles together preferably are easily removable and should be designed so as not to damage the shingle or interfere in any marked degree with the application of the asphalt coating 21 to the face or edges of the two shingles.

As the object of placing th shingles back to back is to prevent the application of the asphalt coating on the mineral wool layer, I may substitute for one of the shingles, if desired, a plate of metal or other material against which a single shingle may be placed, held by clips or other means during the dipping in the bath 32. Also if desired, such a plate may be placed between the two shingles before dipping them in the bath. By the use of such apparatus, or by other means, the process of the invention may be carried out by which process shingles, having upon the underside thereof a lamination of fibrous material of open structure and, particularly, a layer of mineral wool felt, may be provided with a water resisting coating on the face to be exposed thereof and upon the edge surfaces thereof, the edge surfaces of the mineral wool felt and a marginal portion only of the back faces of the mineral wool felt being coated with or absorbing asphalt while the back face substantially is left uncoated and unsaturated so that its insulating quality is maintained.

Having thus described the invention I now claim:

1. A web comprising mineral wool fibers felted to form a web having an open structure to provide heat and sound insulating quality, and a web of mineral wool fibers laminated to said first web and having the fibers thereof felted to form a web with greater strength than said first web and capable of carrying a substantial amount being in the form of of courses of shingles in overlapping arrange thereof a dry lamination of mineral wool fibers providing an open structure, said dry lamination a dryweb of self-sustaining felted structure.

3. A roof construction comprising a plurality ment, and a dry layer of mineral wool fibers providing an open structure, said layer being so positioned on the shingles as to lie between the overlapped portions of two overlapping shingles, said dry layer being in the form of a dry web of self-sustaining felted structure.

4. A roofing sheet comprising a weather-resisting web having laminated thereto a dry web of mineral wool fibres in the form of a selfsustaining felted structure in said dry web.

5. A roofing sheet comprising a weather-resisting web having laminated thereto a dry web of mineral wool fibres in the form of a waterlaid felted structure in said dry web.

6. A roofing element comprising a weather-resisting web having laminated thereto on the underside thereof a dry web of mineral wool fibres in the form of a self-sustaining felted structure in said dry web. 7. A roofing element comprising a weatherresisting web having laminated thereto upon the underside of the portion of the element to be exposed in an assembly of elements in overlapping arrangement a dry web of mineral wool fibres in the form of a self-sustaining felted structure in said dry web.

8. A roofing element comprising a weatherresisting web having laminated thereto upon the underside of the portion of the element which in an assembly of elements in overlapping arrangement is overlapped by a superjacent element a dry web of mineral wool fibres in the form of a self-sustaining felted structure in said dry web.

9. A roofing element comprising a weatherresisting web having laminated thereto upon the upper face of the portion thereof which is to be overlapped by a superjacent element in an assembly of elements in overlapping arrangment a dry web of mineral wool fibres in the form of a self-sustaining felted structure in said dry web.

10. A roofing sheet according to claim 4, said sheet having a sealing coating covering the edge surface of said dry web which is transverse to the face surface of the sheet.

of water repelling impregnating material, the

mineral wool: fibres of said web of greater strength being in predominant amount and formed as a water-laid felted structure in the web.

2. A roof "construction comprising a plurality 11. A roofing sheet according to claim 4, said sheet having a sealing coating covering the edge surface of said dry web transverse to the face of the sheet and also covering a marginal portion only of the face surface of said dry web opposite to that which is next to said weatherresisting web.

12. A shingle formed from a sheet as defined in claim 4 having in the portion thereof to be exposed in an assembly of shingles in overlapping arrangement cut-outs between tabs, said felted web extending above the inner end of the cutouts.

13. A roofing sheet comprising a web of felted fibrous material impregnated with a bituminous water-resisting saturant and carrying on a face. thereof a coating of bituminous material to form a weather-resisting base sheet, and a dry web of mineral wool fibres in the form of a self-sustaim ing felted structure in said dry web laminated to the opposite face of said base sheet and held thereto to form a composite roofing sheet.

14. A roofing element comprising a web of felted fib one material impregnated with an asphalt sat ant and carrying on a face thereof a coating of asphalt to form a weather-resisting base sheet forsaid element, said element having laminated thereto upon a face thereof in an area underlying at least a portion of the base of an element in the roof assembly a dry web of felted mineral wool fibres in the form of a self-sustain ing felted structure in said dry web and held to said base sheet to form a composite insulated roofing element.

15. A roof comprising shingles arranged in horizontal rows or courses, the butts of the shingles in each row being spaced upwardly from those of the next subjacent row of shingles in conventional form. and heat insulating mats oi inorganic fibrous material having open air-filled interstices attached to the under surfaces of the shingles, the length of said mats being equal to the distance between the butts of adjacent rows of shingles and the width of the mats equal to the width of the shingles. the sides and ends of the mats on adjoining shingles abutting so as to forma practically continuous, unbroken mat or blanket of said fibrous material beneath the shingles.

16. A roof comprising shingles arranged in horizontal rows or courses, .the butts of the shingles in each row being spaced upwardly from those of the next subiacent row of shingles in conventional form, and heat insulating mats of inorganic fibrous material having open air-filled interstices attached to the under surfaces of the shingles, said mats being of such size, shape, and position as to abut each other and form in eflect a continuous mat or blanket underlying substantially the entire shingled surface of the roof.

17. The combination of a roofing shingle of greater length than width, and a resilient mat of glass wool having open air-filled interstices, said mat attached to the under surface of the shingle and being coextensive in width with the shingle and extendingurom the upper endof the shingle toward the lower end and terminating at'a point approximately midway between the upper and lower ends of the shingle, the size and arrangement of the mat being such that when the shingle is conventionally built into a roof with like shingles, the sides and ends of said 'mat abut those of the adjoining mats on the surrounding shingles so that said mat is completely surrounded by and merged into the mats of the surrounding shingles to form a practically continuous unbroken mat or blanket of glass wool beneath the shingles.

18. A laminated sheet comprising two layers of mineral wool fibers felted in each layer to form a web, said layers being bound together to form a unitary laminated sheet, said webs each being formed as a self-sustaining structure containing mineral wool fibers in predominant amount, the felted structure of one of said webs being more open than that of the other to provide a substantial insulating quality, the other web being feltedto provide a greater strength in the web than that of the first web. 1

19. A claim according to claim 18 in which the laminations are felted together to form the unitary structure.

20. A claim according to claim 18 in which the lamination of greater strength is impregnated with a bituminous saturant.

ARTHUR DAWEB MAONUT'I.

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