US 2210599 A
Abstract available in
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Description (OCR text may contain errors)
Aug. 6, 1940.. .1. G. PERcY. JR
ROOFING. CONSTRUCTION Filed April 19, 1937 2 Sheets-Sheet 2 ,gmk/fm,
atented' ug. 6, i946 UNTE STATS i'iATfENT OFFiCE l Claims.
This invention relates to roof constructions.
One of the objects of this invention is to provide a roof which is of light weight and which may be quickly and easily applied to a building without requiring expert workmen and which will also be of low cost andattractive appearance.
Another object oi this invention is to provide a roof construction in which thin sheets of metal or other material may be used without necessitating the prefabricating ci such sheets. It is also an object oi" this invention in which the iinperviousness of metal covering sheets is combined with a heat insulating core or supporting membeigto produce a roof of epticnalresistance to heat transfer. A urther .object of the invention is to provide a roei construction in which suitable supporting or core members may be in conjunction with the thin impervious sheets and which roof construction is so formed that su these core members may be made of composition boards of high heat insulating value. Another object is to provide a roofing which is so constructed that it forms its own flashing and counterflashing.
It is also an object of this .invention to provide a construction 'whereby the sheets of metal or other roong material may be held in place by the core members without the use of metal fasening devices or nails passing through or in Jo Contact with the metal covering. Still another object of the invention is to provide a roof construction in which a joint or seam is provided between adjacent sheets of covering material.
Another object is to provide a roof of this kind 35. with reinforcing members, ii such are required.`
It is also an object of the invention to provide a roof which may be placed directly upon the rafters ci a building without requiring the usual sheathing or roof boards, kthereby reducing the 411)) cost and also the weight of the roof.
Other objects of the invention will appear from the following description and claims.
In the accompanying drawings:
Fig. l is a fragmentary perspective view of 4a 451` roof partly broken away to illustrate the construction embodying this invention.
Figs. 2 and 3 are fragmentary perspective views of portions of the roof on an enlarged scale.
fl is a fragmentary perspective view of a 50, roof embodying this invention and showing expansion joint for the flexible sheets.
Fig. 5 is a fragmentary edge View on an enlarged scale of the connection between covering sheets at the ridge of the roof.
55. Fig. 6 is a fragmentary section on a larger scale, showing the manner of applying my improved roofing.
Figs. 7 and 8 are fragmentary sectional perspective views, on a still larger scale, showing steps of the process of applying my improved roof. 5
Figs. 9 and 10 are fragmentary sectional views, showing two additional steps in the applying of my improved roof.
Fig. 11 is a fragmentary section of a iinished roof. 10
Fig. 12 is a perspective View of an implement which may be used in connection with the application of the sheet material to a roof.
Briefly stated my improved roof includes a plurality of core members which preferably are 15 in the form of boards, panels or strips extending lengthwise of the roof and arranged in overlapping arrangement so that the lower edge of one core member or panel overlaps the upper edge of the next lower core member. The exposed 2O surfaces and edges of these core panels are covered by suitable flexible sheet material which is impervious to moisture and substantially unal`- fected by weather. Preferably these sheets are made of any suitable metal which is sufciently durable to withstand moisture and weather conditions. For example, thin sheet copper may be advantageously used for this purpose, since it will withstand exposure to weather for valmost indefinite periods ci time, and for the reason that it will acquire a film of oxide on its exposed surface which provides an attractive appearance. It will be understood, however, that it is not intended to limit this invention to the use of sheet copper since obviously there are other metals which 3 can advantageously be used in the place of copper, and if desired, flexible non-metallic materials in sheet form may be used.
Referring to Figs. 6 to 1G, inclusive, A, A', A2, A3, and A4 represent core members or panels which 40 are arranged in overlapping relation to each other so that the lower portions of all of the core members except the lowest overlap the upper edge portions of the next lower panels `or core members respectively. These core members or panels may be wooden boards or they may be made oi any of the well known heat insulating building materials which may, for example, be formed of Vegetable bers, pulp, or the like.
B, B', B2, B3 and B4 represent successive sheets 50 of flexible covering material which are applied respectively to the core members A, A', A2, A3 and A4. Each of the exible sheets has the lower edge portion thereof suitably arranged under the lower face of its core member and then extends (i lil upwardly across the lower edge of the core mem-- ber and then along the upper face of its core member and terminates at its upper edge between the overlapping parts of its core member and the next higher core member.
In the practical application of my improved roofing construction, I preferably rst secure the lowest core member or panel A loosely in place on the roof supporting structure, which may include rafters l5, and a strip l5 arranged at the eave portion of the roof, for example, by loosely nailing the core member' to the eave strip I6. An edge of the cover sheet B is then inserted between the lower surface of the core member A and the strip It and while this sheet of exible material is hanging down from the strip I6, nails or other fastening devices Il may be driven firmly in place so that the lower edge of the sheet B will be clamped between the core member A and the strip I6. 'Ihe sheet B is then folded across the lower edge of the panel or core member A and across the upper face thereof and will terminate short of the upper edge of the core member A. The core member A may, consequently, also be nailed adjacent to its upper edge, for example, by means of nails it arranged beyond the upper edge of the covering sheet B The second covering sheet B is then laid with an edge thereof in contact with the upper edge of the sheet B and is temporarily held in place in this relation while lying over the lower sheet B and the next core member A is secured in place to clamp the contacting edges of the cover sheets B and B between the overlapping portions of the core members A and A.
Any suitable means for temporarily holding the sheet B' in place may be employed, and I have found that this can be very effectively accomplished by forming a fold or seam connecting the upper edge of a lower sheet with the lower edge of the next higher sheet. Since the covering sheets are made of flexible material, such for example as thin sheet metal, the upper edge of a sheet can readily be turned over after the sheet has been placed upon its core member, and in the construction illustrated by way of example, the upper edge of each covering sheet is provided with a turned over portion 2G under which the lower edge of the next higher sheet is placed. By clinching the turned over part 2E! at intervals, for example, by blows from a hammer, the part 2G will grip the lower edge of another sheet so as to frictionally hold such other sheet in place while the core member for the same is secured in place. The turned over part 2U or other seam connecting adjacent sheets is very desirable, in that it forms a seal which effectively excludes air from passing through the spaces between adjacent sheets of covering material. Any other seam or connection between sheets may be used, or if desired, the seam or connection may be omitted.
Upon placing the core member A in overlapping relation to the upper edge of the core member A and over the adjacent edges of the sheets B and B', which may for example be effected by means of nails 2| and 22, the sheet B is folded over the lower edge of the core member A :and over the upper surface thereof. The securing in place of the next sheet B2, which is shown in Fig. 6 as temporarily clamped in place by the core member A2, is then effected in the same manner as described for the sheet B and these operations are repeated until the upper part or' ridge of the roof is reached, If nails `2l are used, they are preferably driven home firmly so that the heads will be sunk into the core members and will be out of contact with the covering sheets, if the same are of metal. It is, however, possible to eliminate the nails 2| entirely, since the nails I8 and 22 at the upper portions of the panels beyond the covering sheets are ordinarily sufficient to secure the panels in place and to clamp the covering sheets between overlapping parts of the panels.
If the covering sheets of the roof are made of metal or other material which, if bent over, will stay in bent position, the ashing of the roof at the ridge may be readily formed as shown in Fig. 5, by bending, rolling, or folding the upper edges of the upper sheets and 26 of the roof upon each other to form a seam 27. These two upstanding edges may be pressed or clinched together, if the sheets 25 and 26 are of metal, and will form a tight seam at the ridge which eliminates the need for any special ridge member of the roof. If the covering sheets are made of a non-metallic substance, a similar construction may be employed and the upwardly extending member 2li may be cemented into the U-shaped part 21. It will be understood, however', that it is not intended to limit this invention to the particular manner of forming of the flashing at the ridge of the roof, since any other form of ridge construction may be employed, if desired.
It is very desirable in roof construction to avoid having any of the nails or fastenings pass through a metal sheet of the roof, and in my improved roof, it will be noted that the securing of the cover sheets is effected without having any nails or the like passing through or contacting with any covering sheets. This makes it possible to employ ordinary steel nails with a copper roof without danger of electrolysis, particularly -since the holding of the panels and sheets in place is mainly effected by these nails which are driven into the core panels above the upper edges of their covering sheets. If, however, it is found desirable to further secure the panels in place by nails I'I and 2l, nails of the same metal as covering sheets may be employed, for example, copper nails when copper roofing sheets are used, or the heads of the nails may be countersunk into the core panels as shown in the drawings.
I preferably provide means for positively holding the cover sheets against moving downwardly out of their operative positions. For example, I may provide interfitting depressions or recesses in the core panels and cover sheets, preferably in the overlapped portions of the sheets and panels, so that the upper ends of the sheets will be firmly secured in place with reference to their core members. By providing such recesses or depressions in the overlapping portions of the core members, the weight of an upper core member, or the nails or other `securing devices will hold the upper member in clamping engagement to the lower member and will, consequently, prevent the indentations or depressions in the cover sheets from moving upwardly out of the recesses formed in their corel members. Such recesses may obviously be formed in any suitable or desired manner and if the core members are made of a relatively yielding material, such for example as any of the well known fiber boards, a series of blows with a hammer or other rounded or blunt tool upon the overlapped portions of the roofing material may be sufcient to produce the necessary indentations in both the covering sheets and the core members. Preferably,
however, I provide the portions of the core members which are to be overlapped with longitudi-` v plain sheet metal which is quite thin so that the same can readily be formed into the desired shape. Consequently, such metal may be supplied to the roofers in long lengths of a definite Width, and these lengths may be supplied in the form of rolls and sheets of the desired lengths and may, consequently, be readily out from the long sheets. The portion of the hat metal sheets which extend over the grooves 3lin. the core members can, consequently, easily be pressed into the grooves to form the depressed portions 3i of the covering sheets.
If desired, this operation of forming the depressions in the cover sheets may be facilitated b-y the use of a forming implement as shown in Fig. 12, which may consist of a plate-like member 33 having a handle. portion tti. The lower face of the plate-like member 33 may be provided with a longitudinally extending projection 35 which may be of a contour corresponding to that of the grooves 3G in the core members. Consequently, by positioning this plate member over the grooved portions of the core members and t" pressing downwardly on the same, the eXible covering sheets will be formed with depressions 3l as shown in the drawings. The forming irnplement may be moved lengthwise of the sheets so that the grooves 3i can be very quickly formed in the covering sheets. This implement may also be usedin connection with the turning over of the upper edges of the covering sheets, and for this purpose, the plate-like member 33 is also provided 4with an upwardly extending slot Sii, parallel to the `projection 35 and of such depth as to receive the upper edge of a coveringvsheet. In the use of this implement, in` connection with readily flexible sheets such as thin copper, the
' forming implement may rst be passed lengthwise of a covering-sheet with the projection 35 arranged over the groove Sii of a core member to partially form the depressed portion Si in the covering sheet. The implement may then be moved lengthwise over the covering sheet for a second time to completely form the depressed portion 3l in the covering sheet and during this second passage of the implement across the covering sheet, a corner of the sheet may initially be bent upwardly and passed into the slot 35 of this covering member. Upon moving the forming member lengthwise of the covering sheet, the entire upper edge of the sheet will be turned over in the groove 36 into the position shown in Fig.
v8. Consequently, the upper edge of a covering sheet.
the covering sheets in place for the reason that the depression 3i of the covering sheet is arranged between overlapping portions of the core member so that either the nails or other fastening devices or the weight of the overlapping portions of the core members hold the depressions Si in their grooves 3G. In the case of snow, ice
or 'wind loads on the roof, such loads or forces serve to increase the pressure tending to hold the depressions :il in the grooves 3d. The grooves 3 I, in addition to holding the cover sheets in place, also serve to prevent Water from passing upwardly by capillary action between the overlapping parts of adjacent sheets.
Ii the covering sheets of the roof are made of metal, it may be desirable to provide for the expansion and contraction of the metal coversheets due to changes in temperature to which they are exposed. My construction lends itseii readily to the provision of expansion joints for the reason that in my improved roof, the covering sheets are frictionally held in place and not secured by means of nails or the like. kConsequently, if the lengths of the covering sheets and the coefficient of expansion of the material oi' which they are made are sufficient to make ie use. of expansion joints desirable, the coversheets may be formed in two or more parts or lengtms rather than in a continuous length or In such a case, it is only necessary to n rlap adjacent ends of the parts of the sheets the application of the roong may then be tinuoussheet were employed. Since it is desirabie in my improved roof to use thin sheets of covering material, the double thickness of the metal at the overlapping portions is not suflicient to cause any diiiiculty and the roeier, coneequently, proceeds with the folding over of the and with the bending over of their upper .es and forming of the grooves 3l therein,
such are used, in the same manner as if a single length sheet were used. In Figs. l and 4, 40 represents the edges of overlapping parts of covering sheets, and in Fig. il shown in broken lines, represents the overlapped edge of the other part of the sheet. If desired, the overlapping end of a part or length of a sheet may be provided in the portion thereof covering the lower edge of o. core member with drain holes or openings 42, Fig. 4:, through Vwhich any water which has passed between the overlapping portions of parts of a sheet may drain. With my improved roof construction, no securing together of theloverlapping edges is necessary, since these overlapping portions or" the sheets will be held securely in place by the turned overv edges 'in or other earns which may be employed and by the clamping or gripping of the sheets by the overlap-ping portions' of the core members. The seams formed by the over-turned edge 2B at the overiapping portions readily permit lengthwise movement of one part of the sheet relatively to another part at the joint.
My improved roof construction is also very readily adaptable to roofs provided with hips, such for exampleas shown at C in Figs. 1 and 2, or valleys as indicated at D, Figs. l and 3, in which case the flashing and counterashing can be formed by means of the roofing sheetsthemselves without requiring the usual additional parts. This will be readily apparent from Figs. l to 3 inclusive. In Fig. 3 is shown the manner in which the roofing is applied to valleys. The sheets at the portions of the roof which meet iceeded with in the same manner as if a conto form a valley are left of suiiicientl length to extend beyond the valley and to be bent at the valley and extend in overlapping relation for short distances at each side of a valley. Because of the angular relationship between two abut` ting core panels at a valley, the covering sheet of each panel after being bent at the valley, will extend upwardly along the abutting panel at an angle. The upper edges of these bent portions of t'he sheets are then cut so as to lie substantially coincident with the upper edge portions of the sheets which they overlap. The end of one of the sheets is arranged underneath the other sheet at the other side of the valley, and its lower edge will incline upwardly as indicated at 45. The end portion of the other sheet extends over the outer srface of the latter sheet and its lower edge is indicated at 46 in Figs. l and 3. The upper edges of the overlapping portions of the sheets are secured to each other by the turned over seam 25. By means of this construction a flashing is formed which eliminates the use of the usual valleys and provides at the intersection of the two roof planes a portion of double thickness.
In the application of my improved roofing to ahip as clearly shown in Figs. l. and 2, the sheets of covering material which meet at the hip are extended beyond the same, one being underneath the other in a somewhat similar manner as described in connection with the valleys, except that at the hips, the end portions of sheets when bent around the hip extend downwardly. The
extreme overlapping ends of the sheets may, consequently, be bent under the lower edges of the core panels, and the edge i5 of one sheet, will lie underneath the other sheet, whose top edge may be out as indicated at i9 to form an exposed end of the sheet. Since the hips and valleys are formed of double thickness of metal, these parts o-f the roof Will be very durable and will amply protect the building against leaks.
At the ends of the roof, the covering sheets may be bent or folded over the ends of the core members in any suitable or desired manner. If the covering sheets are made of thin metal, the sheets are so applied to the core members as to extend to the desired distance beyond the outer edges of the same and the thin metal sheets can then be readily folded over t'he outer edges of the core members, as shown at 55, and secured on the underface of the same in any suitable manner. These folded ends 55 thoroughly cover the'core members and the entrance of moisture into the space between the core members and the roofing sheets is avoided.
One of the advantages of my improved roofing construction is that the same lends itself particularly well to the use of heat insulating materials in the core. When a building is being reroofed, the structure described may be placed on the former roof, and the core members, therefore, need not have the strength usually required in roof construction. If, however, it' is desired to use my improved roof construction on new roofs and to omit the usual sheathing or roof boards, and at the same, time to employ core members of heat insulating material and of little strength, a series of reinforcing bars may be employed extending crosswise of the rafters. I have found that these reinforcing bars can advantageously be inserted between the overlapping portions of adjacent core members. In Figs. 6, 10 and l1, I have shown reinforcing bars 51 which may, for example, be set in opaardse@ positely disposed grooves or recesses 55 and 55 formed in the overlapping portions of the lower and upper core members. These bars may, for example, be square in cross section, although bars of any other cross-sectional shape may be employed, if desired. When square bars are used, V-shaped notches or recesses are formed in the core members and, if desired, these recesses may be cut or formed simultaneously with the recesses 3i) and at denite distances therefrom. The reinforcing bars may be inserted into the recesses and secured to the rafters by means of staples 60 or the like, and when these staples are used, the nails I8 and 22 may be omitted. It is also possible, if desired, to omit the nails 2l, since the staples and reinforcing bars will secure the panels to the rafters in such a manner that the portions of the panels which overlap the next lower panels will be securely clamped over the next lower panels. l
The reinforcing members described have the further advantage that when an overlapping core member is positioned over the reinforcing bar, the groove 55 therein is placed into registration with the bar 5l so that successive core members will be correctly positioned with relation to each other. It will be noted that these reinforcing bars are also out of contact with the sheets of roofing material. Other types of reinforcing members may, of course, be provided if desired.
In order to illustrate the application of my roof to a building, I have shown in Fig. 6, two core members on which the sheets of covering material are applied. An edge of the third covering sheet B2 has been secured in the bentover portion 20 of the covering member B and the next core member A2 has been secured in place by means of a countersunk nail 2l. The covering sheet B2 is then bent over the lower edge and upper face of the core member A2 and will lie across the groove 36, as shown in Fig. 7. A part of the sheet B2 is next pressed into the groove of the core member A2 and nally the upper edge of the covering sheet B2 is folded upwardly, for example, by means of the slots 36 of the forming implement. The next sheet is then positioned in place and the turned over edge 20 is bent over against the edge of the next sheet B3, for example, by means of hammer blows at intervals lengthwise of the turned over part 29. If the core members are made of a heat insulating material of insuicient strength to adequately support the roof and if reinforcing members are required, the reinforcing bar 5l is then positioned in the groove 58 and fastened by means of staples 60.
The next cover sheet B4 is then applied to the bent-over part of the lower sheet, as has already been described, and the roofing is then proceeded with as already described. As shown in Figs. 6 and 10, the core members A3 and A1 are somewhat separated in order to show clearly the fold or seam between adjacent sheets and the overlapping core members. Preferably the upper core member, however, is pounded tightly into place at the overlapping part by means of a mallet as shown in Fig. 11, and if the core member is of heat insulating material, the upper part of the staple 60 will readily embed itself in the material of the upper core member and the pounding down of the core member will also form a tight joint at the seam between the two covering members. If the core members are of wooden boards or of material of sufficient vantages that it is quick and inexpensive to apply to a building, since the flexible covering material may be used in the form of standard sheets of a width to cooperate with the width of the core members and may be lthin enough so that no performing of these sheets is necessary. When thin sheet metal is used, the bending of the sheets by hand over the panels not only reduces the cost of laying the roofing but also greatly increases the beauty of the same since, for example, when bending a sheet over the lower edge of a panel, the metal at the bend may be more or less irregularly formed by hand, so that hand worked effect is produced and the rigid straight lines at the bend are avoided. The folded over upper edge of -each covering sheet which forms lwith the next sheet a seam, forms also a substantially air-tight joint between adjacent rooiing sheets. By means of the construction described, the thin sheets of covering material, particularly if they are made of metal, will form a roof covering which is substantially impervious not only to water, but also to air, so that the seepage of air through the roof is reduced to a minimum. If the core meinbers are made of a heat insulating material, the roof will in addition to stopping the transfer of heat through the same by seepage of air, also stop the passage of heat through the rcof by conduction, so that a roof of exceptional heat insulating properties is produced. The overlapping arrangement of the core members and the termination of each covering sheet below the upper edge of its core member prevents the passage of heat through the roof by conductivity through the covering sheets, since the air in the interior of the roof will not come in contact with the covering sheets in the overlapping portions of the core members.
While my improved construction has herein been described only as applied to a roof, it will be obvious that it may equally well be used in forming exterior or interior side walls, and consequently, the word roof is herein used to include any wall construction.
I claim as my invention:
l. A roof including a plurality of core members having flat faces and arranged with the lower edge of one core member overlapping the upper edge of a lower core member, a portion of the flat face of a lower core member which is overlapped by another core member having a longitudinally extending recess formed therein, a sheet of metal covering said recessed core member and having a part extending into said recess, a sheet of metalcovering the next higher core member and extending over the lower edge thereof and under the part overlapping said lower core member and bridging said recess, andmeans for securing said core members in operative relation to each other to clamp said sheets between overlapping portions of said core` members and to hold said part of said sheet of said lower core member in said recess.
2. A roof formed of a series of core members extending lengthwise of the roof in a substantially horizontal direction,` a sheet of exible covering material extending from the under surface of a core member over the lower edge thereof and upon the upper surface thereof, another core member arranged with its lower edge in overlapping relation to said first core member, a sheet covering said second core member and held in contact with the rst sheet between the overlapping portions of said core members, said sheets being divided lengthwise into separate parts arranged in overlapping relation to each other to permit each part of each sheet to expand and contract independently of the other' part, the overlapping portion only of one part of a sheet beingprovided at the lower edge of its core member with holes for the escape of moisture which may enter between overlapping parts of a sheet.
3. A roof formed of a series of core members arranged in overlapping relation with the lower edge of one core member overlapping the'upper edge of the `lower core member, a metal sheet for each core member extending from the under surface thereof into the overlapping portion between adjacent core members and terminating at a distance from the upper edge of its core member, and reinforcing bars extending lengthwise of said cores and arranged in the overlapping portions thereof out of contact with said metal sheets.
4. A roof formed of a series of core members arranged in overlapping relation. with the lower edge of one core member overlapping the upper edge o-f the lower core member, a metal sheet for each core member extending from the undei` surface thereof into the overlapping portion between adjacent core members and terminating at a distance from the upper edge of its core member, and reinforcing bars extending lengthwise of said cores and arranged in the overlapping portions thereof out of contact with said metal sheets, the overlapping portions of said core members being grooved to receive said reinforcing members and for positioning adjacent core members in correct relation to each other.
5. A roof construction including a plurality of longitudinally extending -core members arranged one above the other and having the lower edge of one core member overlap the upper edge of a lower core member, some of said core members having end portions thereof terminating adjacent to the other core members `extending at an angle thereto, a metal sheet for each core member extending around the lower edge portion thereof and over the exposed surface thereof and between the overlapping portions of said core members, the sheets covering core members arranged in angular relation to other core members having end portions overlapping said other core members to form weathertight angular portions on said roof.
6. A roof construction including a plurality of longitudinally extending core members arranged one above the other and having the lower edge of one core member overlap the upper edge of a lower core member, some of said core members having end portions thereof terminating adjacent to other core members extending at an angle thereto, a metal sheet for each core member extending around the lower edge portion thereof and over the exposed surface `thereof and between the overlapping portions of said core members, a folded seam connecting adjacent sheets andl arranged between said overlapping portions, a sheet covering one core member extending beyond the end thereof and arranged in overlapping relation to the sheet of an adjacent core member arranged at an angle to said first core member, said overlapping portion of said sheets having their upper edges bent over the lower edge of the next higher sheet.
'7. A roof including a plurality of core panels of heat insulating material having substantially flat upper faces and arranged with the lower portion of one panel overlapping the upper portion of the next lower panel, a sheet of flexible metal covering for each panel, each sheet extending from the under face of its panel across the lower edge and upper face thereof and terminating between the overlapping portions of adjacent panels, the overlapped portions of said panels having grooves in the flat faces thereof into which said metal sheets enter to secure said sheets against displacement relatively to said panels.
8. A roo-f including a plurality of core panels of heat insulating material having substantially flat upper faces and arranged with the lower portion of one panel overlapping the upper portion of the next lower panel, a sheet cf flexible metal covering for each panel, each sheet extending from one overlap across the lower edge and upper surface of a panel to another overlap, the opposite edges of said sheets terminating in the overlaps, whereby the cover sheets are substantially out of contact with air on the underside of the roof to reduce and heat conductivity through the roof, the overlapped portions of said panels having grooves in the iiat faces thereof into which said metal sheets enter to secure said sheets against displacement relatively to said panels.
9. A roofing member including aV core panel arranged to be secured on a roof in overlapping relation to a similar core panel, said core panel having a recess formed in a flat surface thereof at a portion which is to be overlapped by a next higher panel, a metal sheet covering said core member and having a portion thereof bent to extend into said recess and adapted to be conned in said recess by the overlapping flat portion of the next higher core panel to hold the metal sheet in correct relation to its core panel.
l0. A roof including rafters and a plurality of core members extending longitudinally of said roof and transversely of said rafters and having flat upper and lower faces and arranged with the lower edge of one core member overlapping the upper edge of a lower core member, the portion of the flat face of a lower core member which is overlapped by another core member having a depression formed therein, a metal sheet covering each core member, each metal sheet being arranged with its lower edge below the bottom surface of its core member and extending around the lower edge and over the top surface thereof, and terminating in said overlapped portion in contact with the lower portion of the next higher sheet, the metal sheets of said core membersl terminating below the upper edges thereof and having portions extending into said recesses in the depressions of said core members, and fastening means extending tothe upper portion of each core member into said rafters and arranged above and out of contact with said sheets and being covered by the next higher core member.
JOHN G. PERCY, Je.