US3914916A

US3914916A - Roof construction system

Info

Publication number: US3914916A
Application number: US439064A
Authority: US
Inventors: Harold Graves Simpson; Warren Elsworth Scruggs; Richard Clark Mcclain; Norman Douglas Rice
Original assignee: Star Micronics Co Ltd
Current assignee: ROBERTSON-CECO Corp A DE CORP
Priority date: 1973-02-27
Filing date: 1974-02-04
Publication date: 1975-10-28
Anticipated expiration: 1992-10-28

Abstract

A construction plank is disclosed which can be assembled in contiguous, aligned relationship with other planks into a construction unit to form a building roof or other section. The individual planks are of varying geometric shapes and in the preferred embodiment are a composite construction having a structural core or panel member and an exterior sheathing member. A sheet of insulation may be included between the structural panel and exterior sheathing. Opposite edges of the plank are configured to complementarily engage the edges of similar planks in a lap joint to obtain flush assembly. Fasteners secure adjacent panels together at the complementary edge structures. In the preferred embodiment, the plank includes transverse straps extending across the panels which are fastenable to adjacent plank straps and underlying supporting structural members to pretension the straps to increase the lateral strength of the assembly against uplift resulting from wind. A membrane sheet is adhered to the exterior surface of the plank and includes a flap portion adapted to overlie the marginal portion of the next adjacent panel to provide a weatherized covering. The flaps are sealable by flexible interlocking fasteners carried on the sheet flap and marginal portions in the form of rib and groove elements. In the corner area between adjacent planks, overlying membrane flap portions are sealed by a mechanical fastener extending through the flap layers or by vulcanization. In another embodiment the flap edges are sealed by vulcanizing overlapping edges of the membrane sheets. In still another embodiment the plank is adapted as a fire resistant wall component having a suitable interior facing and a weatherized exterior covering.

Description

United States Patent 1191 Simpson et al.

[ ROOF CONSTRUCTION SYSTEM [73] Assignee; Star Manufacturing Company,

' Oklahoma City, Okla.

22 Filed: 1 611.4, 1974 211 Appl. No.: 439,064

Related U.S. Application Data [62] Division of Ser. No. 336,370, Feb. 27, 1973.

[52] US. Cl. 52/748 [51] Int. Cl. E04D 1/34 [58] Field of Search 52/748, 81, 747, 543, 552, 52/540 [56] References Cited UNITED STATES PATENTS 2,323,936 7/1943 Roberts 52/463 2,756,172 7/1956 Kidd 24 201 c 2,874,652 2/1959 Wilson... 52/419 3,070,864 1/1963 Pfeffer 24 201 0 3,093,935 6/1963 Dunn 52/309 3,254,459 6/1966 Bodley 52/81 3,373,537, 3/1968 1 Blayden 52/288 3,455,076 7/1969 Clal'V06..... 5 2 309 3,468,086 9/1969 Warner 1. 52/748 3,667,180 Tischuk 52/309 Primary ExaminerJohn E. Murtagh Attorney, Agent, or =FirmI-Iubbard, Thurman, Turner & Tucker Oct. 28, 1975 [5 7] ABSTRACT A construction plank is disclosed which can be assembled in contiguous, aligned relationship with other planks into a construction unit to form a building roof or other section. The individual planks are of varying geometric shapes and in the preferred embodiment are a composite construction having a structural core or panel member and an exterior sheathing member. A sheet of insulation may be included between the structural panel and exterior sheathing. Opposite edges of the plank are configured to complementarily engage the edges of similar planks in a lap joint to obtain flush assembly. Fasteners secure adjacent panels together at the complementary edge structures. In the preferred embodiment, the plank includes transverse straps extending across the panels which are fastenable to adjacent plank straps and underlying supporting structural members to pretension the straps to increase the lateral strength of the assembly against uplift resulting from wind. A membrane sheet is adhered to the exterior surface of the plank and includes a flap portion adapted to overlie the marginal portion of the next adjacent panel to provide a weatherized covering. The flaps are sealable by flexible interlocking fasteners carried on the sheet flap and marginal portions in the form of rib and groove elements. In the corner area between adjacent planks, overlying membrane flap portions are sealed by a mechanical fastener extending through the flap layers or by vulcanization. In another embodiment the flap edges are sealed by vulcanizing overlapping edges of the membrane sheets. In

. still another embodiment the plank is adapted as a fire resistant wall component having a suitable interior facing and a weatherized exterior covering.

9 Claims, 16 Drawing Figures L lllh 80 Q Ill/1"" US. Patent 0a. 28, 1975 Sheet 1 of5 3,914,916

US Patent Oct. 28, 1975 Sheet 4 of5 3,914,916

ROOF CONSTRUCTION SYSTEM This is a division of application Ser. No. 336,370, filed Feb. 27, 1973.

This invention relates to building construction and more particularly relates to a prefabricated building plank structure adapted for assembly with similar planks to form a roof, wall or other construction section.

Conventional built-up roofing systems have been employed for many years. In this method of construction, a horizontal roof deck is supported on underlying structural beams. The roof deck is covered by a weatherproof membrane usually comprising alternate layers of felt and bitumen to prevent penetration of moisture into the building interior. The membrane is applied in a field operation by application of alternate layers of hot bitumen and felt. Once the membrane is applied to the desired thickness, gravel, rock or similar aggregate material is spread upon the roof to provide protection against weathering. To reduce heat transfer through the roof deck, insulation is often applied to the underside of the roof deck at the interior of the building. Insulation may also be applied on the exterior of the roof deck and subsequently covered with the water resistant membrane.

There are many difficulties with built-up roof systems of the type described above. Since the construction of the build-up roof is entirely a field operation, there is little uniformity of quality from one building to another and consequently the integrity of such a roof structure varies considerably. A built-up roof membrane has a tendency to bubble and crack. This deterioration is due to a number of reasons including expansion and contraction from severe temperature changes, moisture trapped below the water membrane and improper construction techniques. Further, built-up roofs do not withstand heavy foot traffic and are susceptible to damage from traffice. Also considerable safety and environmental hazards exist in the application of hot tar which often gives off toxic fumes and polluting matter. Because of the undesirable nature of the hot tar process, local and federal safety and pollution standards often prohibit or restrict the use of built-up systems which formerly had wide acceptance.

In an attempt to overcome the problems inherent in built-up roofing construction, it has been suggested to construct roofs of prefabricated roofing panels. Roof panels of the prefabricated type generally include some form of insulation such as a polystyrene or urethane foam and wallboard of asbestos or cement sandwiched together. A problem arises in sealing the panel from the weather and water once the panels are arranged in a roof assembly. Often sealing is accomplished by placing a membrane similar to that used in a built-up roof over the roof panels. Obviously, such fabrication procedures require considerable field labor and do not avoid the shortcomings of built-up roofs.

In some instances, prefabricated roof panels have been formed with a weather resistant sheet material preadhered to the panels prior to installation. The preadhered sheet material may be coextensive with the panel. In such a case an additional operation is required to seal the roofing panels at the joints as by use of a mastic or tape. It is also known to provide the panel with a flap along one or several edges which is adapted to overlie and is adhesively secured to an adjacent panel. However, such prior art prefabricating roofing construction has met with limited success because of the manner of assembly and lack of integrity of the adhesively joined membrane sections. The prior art prefabricated roofing construction panels generally require additional field operations, such as application of insulating material to the underside of the panel, to form a completed roofing structure. The unreliability of the prior art prefabricated structures along with the requirement of additional field work substantially adds to the cost of construction of such panels.

In view of the above, there clearly exists in the building industry a need for a prefabricated building plank adapted for assembly to form a construction section with provision for convenient, structurally sound connection and sealing of the planks. The present invention provides such a composite plank having an intermediate structural member preferably in the form of a corrugated sheet metal panel having longitudinally extending corrugations. A suitable interior sheeting such as a wallboard is provided at one side of the corrugated panel. A layer of insulation and sheeting is provided at the opposite exterior side of the plank. The exterior sheeting may be a plywood or composite board material. A membrane of weatherproof material is bonded to the outer surface of the composite plank. The membrane is formed with a flap along one or several edges which is adapted to overlie a marginal portion of an adjacent panel. The membrane flap is adapted to sealingly engage the marginal portion of the next plank by vulcanization or by virtue'of interlocking fastener members cooperable with the flap and the marginal portion of the adjacent plank. The interlocking fastener may also take the form of a mechanical clip or interengageable flexible rib and groove member. The present invention further provides a corner seal to complete an assembled structure. At the common juncture of several planks a condition exists .where several flaps overlie one another. A mechanical fastener is used to compress the layers together at this juncture and seal the exterior surface of the membrane in the comer area.

A further aspect of the invention provides for assembly of a number of planks to form a roof having good longitudinal and lateral strength. The individual planks have opposite edge portions which are complementary and which engage the edge of adjacent planks to form a lap joint with the internal structural panel forming a part of the joint. When used as a roof or wall plank and when the plank must resist a load tending to separate the plank from its structural support, an additional member in the form of a transversely extending strap member is included to extend across each plank and connect to an adjoining plank strap member and to the supporting structural member. The straps are pretensioned to provide excellent lateral strength to resist wind loadings that tend to lift the roof assembly.

The basic plank structure is also adaptable for use in construction of firewalls and other partitions. As a wall component the plank is modified and is fabricated with a suitable interior facing such as a vinyl or paper covering and has a suitable exterior weatherized covering such as metal or simulated brick or stone. The planks are complementary and can be assembled in interlocking fashion at their edges to form a wall. Caulking or joint compound applied along the plank edges seals the structure.

The plank of the present invention is a highly efficient structural member giving adequate support and resistance to imposed loads. The plank can be factory assembled with a minimum of labor and a maximum of quality control resulting in an economical product with minimum field maintenance problems. The plank is highly versatile and can be fabricated with varying characteristics to meet different requirements of shape, strength, weight, thickness ratio, fire characteristics and thermal conductivity. Field installation is relatively simple using mechanical fasteners and conventional bonding agents. The plank can be easily altered in the field to meet special requirements by normal drilling, sawing, screwing and cutting operations. As a roof or wall member, the plank may incorporate the tension strap members as well as a membrane which is preadhered to each plank. The membrane is easily sealable at edge and corner portions to provide a tight, protective covering. As a firewall or other partition, the plank includes suitable exterior and interior coverings to eliminate the requirement for any additional finish work.

The above and additional objects and advantages of the present invention will become more apparent by reference to the following specification, claims and appended drawings in which:

FIG. 1 is a fragmentary perspective view illustrating the plank of the present invention as applied to the roof structure of a typical building;

FIG. 2 is an enlarged cross-sectional view of a portion of the structure taken along lines 2-2 of FIG. 1;

FIG. 3 is an enlarged cross-sectional view taken along lines 3-3 of FIG. 1;

FIG. 4 is a cross-sectional view taken along lines 44 of FIG. 1;

FIG. 5 is an enlarged fragmentary sectional view of a connection between adjacent roof panel members;

FIG. 6 is an enlarged sectional view showing in detail one of form of the connection between mating roof membrane sections;

FIG. 7 is a plan view of a single plank;

FIG. 8 is fragmentary sectional view showing an alternate method of sealing adjacent membrane sections;

FIG. 9 is a sectional view of a mechanical clamp for securing adjacent membrane sections;

FIG. 10 is a fragmentary plan view of a corner joint at the juncture of adjacent panels;

FIG. 11 is a sectional view taken along lines l1ll of FIG. 10;

FIGS. 12 and 13 are sectional views showing alternate sealing structures for the corner joint;

FIG. 14 shows a cross-sectional view of another embodiment of the present invention adaptable for use as a firewall component;

FIG. 15 shows the joint between the wall planks of the embodiment of FIG. 14; and

FIG. 16 shows a fragmentary perspective view of the connection of FIG. 5.

Referring now to the drawings, FIG. 1 shows a roof assembly generally designated by the numeral 10 supported on an underlying support generally designated 11 having a primary and secondary structure. More particularly, the primary roof structure 11 includes transversely extending beam or rafter members 12 which, as is known in the building art, are supported on columns or bearing walls. The secondary support structure includes longitudinally extending purlins l3 supported on the upper surface of rafters 12. The purlins are generlly Z-shaped having upper horizontal flange member 14. The-primary and secondary roof support structure shown is for purposes of explanation only and, as will be appreciated, forms no part of the present invention. It will be obvious to those skilled in the art that other supporting structures could be similarly used.

The roof assembly 10 includes a plurality of individual planks 15. As is seen in FIG. 1, planks 15 are generally rectangular and adapted to span several purlins 13. The geometric shape, however, may vary with the specific requirements. The individual planks 15 are contiguously aligned in a side-by-side and end-to-end arrangement to form the roof structure 10, abutting at common corner junctures 16. Roof planks 15 include an outer membrane sheet 20 of weather resistant sheet material preadhered to the exterior surface in a manner providing a pair of adjacent edge portions or flaps 36 and 37 which extend beyond the corresponding plank edges and overlap the marginal portion of adjacent planks. At the corner juncture 16 of several planks, multiple layers of membrane overlay one another and are sealed at corner seal 21. The edge seal and corner seal arrangement will be explained in detail with reference to subsequent drawing figures.

Referring additionally to FIGS. 2 through 7 which illustrate the details of construction of the plank sections 15, the individual plank sections 15 are of a longitudinal composite structure having intermediate structural panel member 24. Panel 24 is shown as a corrugated sheet metal section having parallel upper surface 25 and lower surface 26 formed by the laterally spaced, longitudinally extending corrugations 27 in the panel. The particular cross-sectional shape and configuration of corrugations 27 is subject to wide variation as the panel serves as. the core member of the composite plank 15 providing spacing and structural support for the remaining members of the plank. Spacers 29, shown as generally rectangular members of plastic or wood, longitudinally extend along the underside of corrugated panel 24. The depth of spacers 29 approximately corresponds to the depth of the corrugations 27 in panel 24 so that the bottom surface of the spacers 29 is coplanar with lower panel surface 26. Interior sheathing panel 30 is affixed to the underside of corrugated panel 24 and to spacers 29. Preferably panel 30 is a wallboard or plasterboard. A sheet of insulating material 32 is applied across the upper surface 25 of panel 24. Insulating sheet 32 may be a material such as ceramic, polystyrene or urethane foamed in place or as a rigid panel. Exterior sheathing is provided by panel 34. Panel 34 covers the upper surface of insulation 32 and provides a hard, smooth exterior surface. Panel 34 may be of a variety of materials and is preferably a rigid panel of a composite hard board, plastic or plywood. Thus it will be seen that the core of the plank is a composite structure having an intermediate structural panel interposed between exterior and interior sheathing panels. The core structure may be secured together by adhesives or bonding agents at the interface of the various layers or, as is shown, fasteners or staples 35 may extend through the core to secure the various panel components of the structure together.

Other materials may be selected. For example, insulation layer 32 may be a foamed urethane of relatively low density covering panel 24. Panel 24 may be formed in place by an application of a second layer of relatively dense urethane. The outer layer of dense urethane is suitable as sheathing. This type of construction will speed production and eliminate the need for adhesives or fasteners to secure the plank components into a composite structure.

The basic plank or core structure is stronger than the individual components because the sandwich construction serves to stabilize the corrugated panel and increase the load carrying capacity. The construction is relatively deep in cross section utilizing the insulation material as a web so that the interior and exterior sheathing function similar to structural flanges. This results in increased flexual strength and good deflection characteristics.

The upper surface of plank is covered with a sheet of membrane in the form of a weather resistant material to protect and seal the roof system 10. Sheet 20 is substantially coextensive with the plank along adjacent lateral and

longitudinal edges

43 and 41. Along the two opposite adjacent edges, 40 and 42, a

flap portion

37 and 36, respectively, extend laterally beyond the corresponding edge adjoining at corner 21 adapted to overlie a marginal or selvage portion of the membrane on an adjacent plank. Membrane 20 is preferably a natural or synthetic rubber or plastic bonded or adhesively joined to the upper surface of upper panel 34 and for example may be a material known under the tradename I-Iypalon manufactured by the DuPont Chemical Company. Similarly, the membrane can be fabricated from a light gauge metal such as aluminum.

The opposite

longitudinal edges

40 and 41 of adjacent planks are complementary and engage to form a lap joint when the planks are assembled in abutting engagement to form a construction unit or section. Edge 41 of the plank is formed having interior panel member 30 recessed laterally inward of

panel members

32 and 34. Opposite plank edge 40 is complementarily configured having inner panel member 30 projecting laterally beyond

upper panel members

32 and 34. A spacer member 28 extends longitudinally along edge 40 centered below the terminal edges of

panels

32 and 34 to receive fastener members and to stiffen and reinforce the joint at the plank edges. When the

edges

40 and 41 of adjacent planks are abutted, a lap joint results, sometimes referred to as a ship lap joint At plank edge 41, corrugated panel 24 is formed with a horizontally extending section 48 terminating at edge 21. lnwardly spaced from the outer end of section 48 is abutment or projection 49. Corrugation rib 50 extends laterally beyond the terminal edge panel 30 at plank edge 41 and is connected to panel member 48 by diagonally extending leg 51.

At plank edge 40, horizontal lip 53 of panel 24 projects beyond the edge of panel 32. Member 54 extends diagonally between

corrugated panel member

53 and 55. The shoulder formed at the intersection of members 53 and 54 corresponds to projection 49 on the opposite panel edge 40. When adjacent planks are placed in contiguous alignment with

edges

40 and 41 engaged, a joint is formed with opposite edge structures of corrugated panel 24 overlapping and reinforcing the joint. Projection 49 carried on panel 24 engages opposite panel member 54 to regulate the depth of relative engagement between adjacent planks in an assembled position.

The plank assembly consisting of the individual planks 15 is secured at intervals along adjacent longitudinal panel edges 40 and 41 by fastening members 60 which penetrate through lapped

panel members

48 and 53 and into reinforcing member 28. Member 28 stiffens the lap joint and provides backup material for penetration by fastener 60. Fastener 60 is displaced laterally from the crevice between abutting exterior panels 34 in a recess 61 provided in the edge of panel 41. Fastener 60 for convenience is shown as a self-tapping metal screw but obviously may be in the form of a rivet, bolt or other means of mechanical fastener.

The opposite lateral edges or ends 42 and 43 of planks 15 are configured to abut in a lap joint when panels are abutted end-to-end as seen in FIG. 4. Panel member 24 and interior member 30 are longitudinally recessed at edge 42. Opposite plank edge 43 is formed with

members

32 and 34 inwardly recessed. Flap portion 36 of membrane 20 projects beyond edge 42 to cover the joint formed between abutting panel sections and overlap the marginal or selvage portion of the membrane of the adjacent plank. Preferably as seen in FIG. 4, the major portion of the interface of the shiplap joint between lateral ends of abutting panels directly overlies the flange 14 of purlin 13 to give support to the joint.

The lateral strength of the assembly 10 is reinforced by the inclusion of laterally extending tension members extending in parallel at spaced intervals across the planks. As seen in FIG. 1, the individual planks are of substantial length traversing several purlins. Preferably a lateral tension member 70 in the form of one or more flexible straps is included in the plank at a position corresponding to location of intermediate purlins. The detail of strap members 70 is best seen in FIGS. 3, 5 and 16. Strap members 70 extend laterally across the upper surface of the panel 34 beneath membrane sheet 20. The opposite ends 71 and 72 of straps 70 extend be yond the edges of the corresponding panel 34. When planks 15 are placed in engagement, the strap ends 71 and 72 are secured to corrugated panel 29 by an appropriate fastener such as self-tapping metal screw 74. Fastener 74 secures the strap ends 71 and 72 and penetrates into the corrugated panel section 53 and reinforcing member 28. FIG. 5 shows in phantom lines the position assumed by the strap ends prior to being secured in place. Once the ends of the strap are secured in place, the fasteners 74 are tightened and the strap is placed in tension or prestressed to resist upward loads on the plank such as are induced by wind currents blowing across the upper surface of the roof plank causing reduced pressure at the roof surface.

Recesses

75 and 76 are provided at opposite longitudinal plank edges at a location corresponding to the strap ends to facilitate tensioning the strap and to locate the strap ends to obtain a proper distribution of forces and minimize excessive crushing of the panel edges. The use of the straps permits assembly of the planks without the necessity of placing fasteners through surface of the individual planks.

A Z-section clip 78 is provided at the connection of strap ends to reinforce the connection. Clip 78 conforms in shape to corrugated panel sections 53 and 54 and has upper and lower flanges 77 and 79. As seen in FIGS. 5 and 15, clip 78 is interposed between the overlapping section of panel 24 with fastener 74 secured to flange 77 of the clip. A second fastener extends through the the lower flange 79 of the clip 78 tying the strap ends through the clip to the flange 14 of subjacent purlin 13. If necessary, several longitudinally spaced

fasteners

74 and 80 may be provided in the clip flanges 77 and 78.

One or more spacers 65 are provided between the adjoining ends of the straps and panel section 48. Spacers 65 are preferably a compressible insulative material. The strap ends 71 and 72 lay against the spacers which give support to start fastener 74 through the metal. As fastener 74 penetrates the lapped panel sections, the spacer is compressed. The compressed spacer serves to minimize heat conductivity between straps 70, panel 24, and supporting purlin 13 When the assembly is complete, each tension strap 70 is tied at opposite ends to purlin 13 and, under upward loadings caused by a reduced pressure at the roof surface from wind, assumes the general shape of a catenary curve. The panel will correspondingly deflect slightly to assume a similar shape. Normal loadings due to weight are resisted in the roof supporting structure at the purlins and rafters. The strap 70 is designed so the angle of the straps over the corner of panel 34 minimizes compression over the panel while maintaining the shape of a catenary curve which gives transverse strength to the plank.

Tne tension straps 70 may be embedded within upper sheathing 34. With certain materials, the upper sheathing 34 may itself provide the function of laterally strengthening the plank where the sheathing has adequate tensile strength characteristics. The sheathing could be directly tied to the supporting structure or could be tied to the supporting structure through clips 78. Either way, the sheathing could serve to distribute loadings across the panel to the supporting structure so as to reduce the number of fasteners transverse of the planks.

One form of a closure assembly for securing

overlying flap portions

36 and 37 to adjacent panels is shown in FIGS. 6 and 7. Closure assembly 85 includes a member 86 formed on the underside of the edge of

flaps

36 and 37. Member 86 has downwardly projecting rib sections 91 extending parallel to the respective panel edge. The spaced'apart rib portions 91 define parallel extending grooves 92 in the underside of flap 36. The opposite coacting member 88 of fastener 85 is provided in the upper surface of membrane at a location on the selvage

adjacent edges

41 and 43. Fastener member 88 is similar to member 86 and comprises a parallel series of upwardly projecting ribs 93 which define parallel grooves 94. The ribs and grooves of

fastener sections

86 and 88 are adapted to interlock when force is applied, for example, to member 86 forcing ribs 91 into corresponding grooves 94. The

coacting sections

86 and 88 are thus capable of being interlocked in zipper fashion to form a tight mechanical lock. Various configurations of the ribs and grooves are suitable for the fastener arrangement. A preferred configuration of this general type of fastener is shown and described in US. Pat. No. 3,373,464.

The flexible interlocking fastener 85 is particularly suitable for securing the membrane covering 20 over an assembly of the planks 15. The .entire closure 85 can be fabricated into the membrane as part of the plank at the factory. The

coacting fastener portions

86 and 88 are weatherproof and waterproof when engaged. Sealing can be accomplished by the workmen when the panels are assembled. No special equipment is required to seal the adjacentmembrane sections. Obviously an adhesive or a vulcanizing agent can be applied between the grooves and ribs at the time of securing the membranes together to further ensure against penetration of moisture and seal the interior plank structure.

FIG. 8 shows an alternate form of the flap portions and of the membrane 20. In this structure a plank flap section 36a is associated with the panel and is adapted to be sealed to the adjacent panel membrane by vulcanization or application of an adhesive. Flaps 36a do not carry an integral mechanical seal but are substantially flat and adapted to lap the adjacent plank membrane. The material of the membrane is preferably a natural or synthetic rubber or a thermosetting resin which characteristically is adaptable to vulcanization. Once the panels are assembled with flaps 36a overlying the adjacent panel, the membrane can be sealed by application of heat along flaps 36a with heating unit 98 which is a flat iron having appropriate temperature control. Following application of heat, a pressure member 99, shown as a weighted roller, serves to compress the overlying membrane members together to ensure a good seal. The temperature applied at flaps 36a should be sufficient to at least partially melt the upper membrane so that the underlying layer is heated and bonded to the flap 36a. The flaps 36a can also be adhered to the surface of adjacent panels by use of a suitable bonding agent or adhesive with or without the application of heat. vulcanization can also be carried out by use of sonic, electromagnetic or heat waves to cause molecular bonding when the flaps are brought together under pressure.

The lapping lateral and longitudinal edges of the weathering membrane can also be sealed by a mechanical clip as shown in FIG. 9. To adapt the membrane to the mechanical fastener shown in FIG. 9, the edge of the membrane opposite flap 36b is provided with a loose selvage portion 100. Clip 101 has a rounded upper surface 102 and intermediate section 103 and a reversely bent lower lip 104. Clip 101 is continuous and is closed at end 105.

Ribs

106, 107 and 108 extend longitudinally along one edge of the clip and are adapted to engage one another when clip 101 is in a closed position. Selvage is received between

clip elements

102 and 103 and flap portion 36b oppositely extends between

clip elements

103 and 104. Vertical projections 110 extend downwardly from intermediate element 103 engaging opposite sides of the juncture between the planks. An additional projection 1 11 at end engages one of the planks. Fastener 112 extends vertically between

clip elements

102 and 103. In assembly of the clip, mastic or adhesive may be applied in

ribs

106 and 107 to seal the membrane to the clip. It will be obvious that as fastener 112 is tightened and the clip compressed, the overlapping portions of the membrane will be sealed to the clip and the vertical projections on the underside of the clip will be placed in tension to apply pressure to the membrane. One advantage of the clip arrangement is that any water entering around fastener 1 12 does not penetrate the membrane but simply will run out the end of the clip. The clip effects a sea] at 106, 107 and 108 which allows the use of the fourway corner seal 21 to completely weatherproof the membrane at the edge and comer junctures. The corner seal is described in detail in the following paragraphs.

The present invention also makes provision for sealing the membrane in the comer area of the planks. At the juncture of three or four planks, a comer area 118 is formed with a number of membrane sections overlying one another. This is best seen in FIGS. 10 and 11. It will be noted that the common membrane corner area 118 is diagonally disposed from the corner 16 formed between adjacent corresponding planks. A corner seal assembly generally designated by the numeral 21 seals the overlying membrane sections in the common corner area of planks. A flat metal bearing plate 120 underlies the overlying membrane section. Preferably plate 120 is formed as an integral part of the plank structure to facilitate assembly. The membrane flaps are lapped over lower plate 120. The opposite side of the corner joint is defined by generally convex cap or disk member 125 having an annular lip portion 126. Mastic may be applied around the periphery of the lip 126, A fastener 127 extends through disk 125 into opposite bearing plate 120 and into subjacent plank c. Tightening of the mechanical fastener will draw the disk 125 down, tightly compressing the membrane sections together between disk 125 and plate 120 providing a watertight seal. The area of bearing plate 120 and the area encompassed by the disk 125 should be large enough to provide for any misalignment which might occur in the assembly of the plank sections.

FIG. 12 shows an alternate embodiment of the corner seal. Embodiment of FIG. 12 is generally designated by the numeral 131 and includes flat bearing plate member 130 underlying the joint between adjacent plank members. Membrane flaps are lapped across plate 130. The upper side of the joint includes member 135 which has a center cup 136 with annular flange 137 projecting around the upper lip of the cup. Flange 137 engages the surface of the outermost membrane and the inner end of cup 136 contacts bearing plate member 130 through an appropriate cutout in the membranes. Bearing plate 130 and joint member 135 are both of a heat conductive material. Once the joint is assembled, heat is applied to member 135 within the cup 136. The substantial surface area of cup 136 conducts heat to member 130 and serves to bond or vulcanize the overlying layers of membrane to one another and to the

joint members

130 and 135. The vulcanization or bonding results in a secure weathertight seal.

FIG. 13 shows still another embodiment of the corner seal joint generally designated by the numeral 141. Joint 141 includes a bottom bearing plate 140 formed as part of the plank at the membrane lap. The upper joint member 145 includes a generally flat plate 146 supporting downwardly projecting spikes or pins 147. The joint is formed by first placing bearing plate 140 in place and then lapping the adjacent membrane sections over plate 140. Member 145 is then aligned over plate 140 and pressure is applied to plate 146 to cause the spike members 147 to pierce through the layers of the membrane until contact with bottom plate 140 is established.

Members

140 and 145 are of a heat conductive material and the joint is sealed by application of heat to plate 146 which is conducted by pins 147 to plate 140. This results in a substantially uniform heating of the joint and the membranes in the area of the joint, resulting in a vulcanized secure seal.

The present invention will be better understood from the following description of assembly of a typical roof assembly using the construction planks of the present invention. A substructure comprising primary and secondary roof support members in the form of the lateral extending rafters 12 and longitudinally extending purlins 13 will be erected in place by a field construction crew. Once the substructure is in place the construction of the roof can proceed. It will be noted that while the planks are described as being roof panels, it will be obvious that the planks are adaptable for use as other construction sections or units such as floors or load bearing or non-load bearing partition members.

The construction crew will position the proper number of planks on the purlins with the planks l5 transversely resting across the purlins as seen in FIG. 1. Generally the relationship of the length of the planks to the purlin spacing is such that the individual planks transverse several purlins having opposite plank ends 42 and 43 terminating above a flange 14 of the purlins. The planks are contiguously aligned in an end-to-end and side-by-side relationship with the complementary edge structures in engagement. The adjacent

longitudinal edges

40 and 41 of the planks are secured together by fasteners 60 extending through overlapping

sections

48 and 53 of the panel 24 at locations intermediate the purlins. To further increase the lateral strength of the sections and to resist applied stresses induced by wind loadings, tension members are then secured in place. This is done by securing Z-clip 78 in place over the subjacent purlin 13 by means of fastener extending through lower leg 79 of the clip. Adjacent ends 71 and 72 of thetension strap 70 are secured together by fastener 74 and pulled tight to place tension on the members extending across the panels. Spacer 65 between the straps and the panel section 48 gives adequate support to the fastener to allow the fastener to start through the metal at the desired location. As the fastener penetrates the metal, the head of the fastener pulls the strap 70 in tension and compresses the foam spacer 65. In the compressed condition, spacer 65 serves to seal around the fastener as well as reduce heat transfer between the panel 24 and the tension member 70.

The inclusion of the straps is an important factor in the construction of a roof or other section where the plank loading tends to separate the planks from their support structure. The straps extends laterally across the roof, being attached to the support structure only at the plank edges. All necessary fasteners can be secured from the top and intermediate fasteners extending through the planks are not required. Thus potential sources of leakage are eliminated and field assembly is expedited.

The lateral edges 42 and 43 of abutting planks are simply placed in engagement forming a shiplap joint as seen in FIG. 4. As explained. above, the end joint is preferably located immediately above the purlins to provide support for the joint.

Once the planks are in place, the weatherproof membrane 20 can be sealed. End flap 36 is overlayed on the next adjacent panel. Fastener assembly 86 carried on the marginal portion of the membranes is secured by applying force to one of the

fastener members

86 or 88 to engage the fastener members in coacting relationship. This can be done by simply applying manual force to the upper surface of member 86 or the interlocking portion may be fastened together by progressively mating the sheets with a slide fastener so that the projections of one of the sheets fits into the channel of the other. The concurrent application of a bonding or adhesive agent may be included when the fastener sections are engaged. Edge flap sections 37 are secured in place in similar fashion with the fasteners engaged.

Alternately the overlying end and edge seal flaps 36 and 37 can be sealed to the adjacent marginal membrane portion by application of heat to obtain a seal. With this method, a source of heat such as a flat iron or blower emitting hot air will be run along the overlapping flap. The temperature must be at least the melting point or vulcanization point of the membrane material. Heat is applied to the top side of the overlap and causes the top layer of the membrane to melt or partially melt to form a bond between the members. Application of pressure immediately following application of heat will compress the joint and further ensure the integrity of the joint.

Once four contiguous planks have been placed with the membrane edges sealed, membrane corner seal 21 can be completed. Disk 125 is placed on the top membrane layer above lower plate 120. Fastener 127 is driven through member 125 and into lower plate 120 causing the intermediate overlying membrane layers to be compressed together tightly sealing the corner. Factory applied mastic at lip 126 will further serve to seal the corner. Any misalignment of planks occurring during assembly can be accommodated and taken up at the corner seal. As explained above in a further aspect of the present invention, the corner seal may include the step of vulcanizing the overlaying membrane portions together. Heat applied to the exterior member 125 is conducted to the lower bearing plate 120 causing the membrane layers to vulcanize to one another and to the comer seal structure. The assembly of the roof system continues substantially as described until the entire roof is completed.

The plank can be formed into a roof section with relative speed as compared to former built-up roof systems. A roof system using the basic plank structure can be installed in a wide range of weather conditions. Ambient temperature is not critical as with application of bitumen. Because of the modular nature of the plank, the plank can be placed and erected quickly to enclose the building in a minimum of time allowing crews to complete interior work in a protected environment.

The plank, because of its structural design, provides a smooth hard surface which is very resistant to exterior damage from foot traffic, weather and vibration. With the increased trend toward roof mounted accessories, foot traffic is an increased problem. The unique combination of materials of the present plank provides a hard walking surface directly under the weather resistant membrane where it is most needed to support the membrane. The plank is also particularly adaptable for use with a wide variety of accessories. The panel can be cut, sawed or bored to accept various fittings and accessories such as windows, ventilators, or conduits for electrical or mechanical accessories.

Other advantages to the present system reside in the composite construction of the plank element. The insulation panel is placed over the primary structural member rather than under it so as to minimize the expansion and contraction of the primary structural element. This configuration also helps to spread concentrated loads over a wider part of the roof element thus reducing the possibility of localized roof failure. The inner wall panel may be used with no additional interior treatment as a wall surface presenting an aesthetically pleasing construction. Another advantage of the roof plank of the present invention is that the vapor barrier, which is generally defined by the corrugated panel 29, can be located on the interior or the hot side of the panel. This way damaging and deteriorating condensation within the plank interior is avoided.

The fire resistance of the roof plank is also particularly good since the composite materials are low flammable or not flammable. Further, application of asphalt or flammable or toxic material is not required in the construction. It is known that build-up roofs present a fire hazard since the asphalt surface, when heated by fire, can generate gaseous combustible fumes which contribute to the spread of fire.

Because of its good structural and fire resistant characteristics the panel of the present invention lends itself to use in the construction of a floor or wall on other construction units. FIG. 14 illustrates a cross sectional view of a modification of the invention adapted for use as a vertical firewall structure. The embodiment of FIG. 14 is generally designated by the numeral 150. The basic core structure of the plank is similar to that described with reference to FIG. 3 and includes intermediate corrugated panel 27a enclosed on one side by interior sheet member 30a and on the other by insulation 32a and exterior sheet 340. Panel 27a can be corrugated in a wide variety of shapes. Spacers 29a and reinforcing member 28a extend longitudinally within plank 150. Preferably spacers 28a and 29a are of a fire resistant material such as gypsum or a foamed plastic. Opposite edges structures 40a and 41a are configurated for lapping engagement with reference to the previously described embodiment. Similarly, the opposite lateral edges may be adapted to abbut in a lap joint if the height of the wall exceeds the length of a panel. For most installations the plank ends will be squared as the typical wall will not require vertically stacking the planks 150.

Panel 30a on the interior of the plank is wallboard or a similar material having a good fire rating. An interior treatment such as a vinyl or paper 151 covers the interior side of panel 30a. Panel 34a may be plywood or a hardboard or similar composite material.

The exterior surface of upper panel 34a is weatherized with a covering 153. Covering 153 protects the plank and also is selected to give the desired exterior surface appearance such as aluminum, painted steel or simulated stone.

To form a firewall structure, the wall panels are vertically aligned with edges 40a and 41a lapping and secured with fasteners 60a penetrating into reinforcing members 28a as seen in FIG. 15. Fasteners 80a project into appropriately spaced vertical structural members 156. The crevice between the panel edges is filled with a butyl caulking compound or the equivalent.

The advantages to such a fabricated wall structure are many. Less foundation is required because the weight of the planks is substantially less than the equivalent structure of concrete or block. The prefinished exterior and interior permits fast installation and elimi-' nates need for additional work. The components of the plank, all being non-flammable or fire resistant, result in a structure with a good U-factor. and resultant reduction in building and insurance costs.

Thus the present invention provides a construction section which can be used as a basic element of a roof, or other construction unit. The basic plank is a particularly good structural member because it incorporates features which give it both good longitudinal and lateral strength. Used as a roof deck, the transversely extending tension strap members serve to resist upward loading on roof due to reduced pressures at the outer roof surface because of wind. As a wall component, the plank can be prefinished at the interior and exterior surfaces. Factory assembly of the plank allows minimum labor cost and provides maximum quality control resulting in more economical product with fewer field maintenance problems. The plank is highly versatile and allows substantial variance of construction to meet various end needs such as strength, weight, thickness, fire characteristics and thermal conductivity.

It will be obvious to those skilled in the art to make modifications and changes to the panels of the present invention. For example, it will be obvious to substitute other structural elements for the interior panel member such as aluminum or fiberglass sheeting. Similarly, various forms of insulation and interior and exterior panels can be used. The membrane may similarly be of a wide variety of natural or synthetic materials to provide the desired weather and waterproof exterior. To the extent that these changes and modifications do not depart from the spirit and scope of the present invention they are intended to be encompassed therein.

What is claimed is:

l. A method of roof construction comprising:

erecting a roof supporting substructure;

arranging a multiplicity of prefabricated roof planks each carrying an integral membrane sheet on said substructure in aligned contiguous relationship to enclose said roof;

secruing said planks together at their abutting edges and ends in a lapping joint;

securing spaced apart transversely extending strap members across said panels to said substructure and pretensioning said straps;

sealing the membrane sheet carried on the planks one to another to seal the roof; and

sealing the membrane comer areas adjacent abutting planks.

2. A method of roof construction comprising:

erecting a roof supporting substructure; arranging a multiplicity of elongated, prefabricated panel members in contiguous relationship on the roof supporting substructure, the prefabricated panel members having waterproof upper surfaces and a flexible waterproof flap extending from the waterproof upper surface of at least one edge of each contiguous pair of edges of adjacent panel members, the flap being sealed along its length to the waterproof surface of the panel member to which it is attached to form a continuation of the waterproof surface; mechanically fastening the opposite edges of the panel members to the underlying substructure to resist upwardly directed wind loads on the panels by means of tension forces developed in the panel member between the opposite edges; and

positioning a flexible flap over the mechanically fastened edges and sealing the flexible flap to the adjacent panel member to form a continuous watertight membrane between the watertight surfaces of the adjacent panel members along the contiguous edges of the panel members.

3. A method of roof construction comprising:

erecting a roof supporting substructure;

arranging a multiplicity of elongated, prefabricated panel members in contiguous relationship on the roof supporting substructure, the prefabricated panel members having waterproof upper surfaces and a flexible waterproof flap extending from the waterproof upper surface of at least one edge of each contiguous pair of edges of adjacent panel members, the flap being sealed along its length to the waterproof surface of the panel member to which it is attached to form a continuation of the waterproof surface, and having one half of a mechanically interlocking and sealing fastener, the other panel having a mating half of the fastener sealed along its length to the waterproof surface of the other of the adjacent panel members;

mechanically fastening the opposite edges of the panel members to the underlying substructure to resist upwardly directed wind loads on the panels by means of tension forces developed in the panel member; and

positioning a flexible flap over the mechanically fastened edges of the panel members and mechanically engaging the halves of the fasteners to form a continuous watertight membrane between the watertight surfaces of the adjacent panel members along the contiguous edges of the panel members.

4. A method of roof construction comprising:

erecting a roof supporting substructure;

arranging a multiplicity of elongated, prefabricated panel members in contiguous relationship on the roof supporting substructure, the prefabricated panel members having a waterproof upper surface formed by a flexible waterproof membrane adhered to a tension member having a transverse tensil strength, the membrane extending beyond at least one edge of each contiguous pair of edges of adjacent panel members to form a flap;

mechanically fastening the opposite edges of the tension members of the panel to the underlying substructure to resist upwardly directed wind loads on the panels by means of transverse tension forces developed in the tension member between the fastened edges; and

positioning a flexible flap over the mechanically fastened edges of the tension member and sealing the flexible flap to the membrane of the adjacent panel member to form a continuous watertight membrane.

5. A method of roof construction comprising:

erecting a roof supporting substructure including a plurality of spaced, parallel beam members;

arranging a multiplicity of rectangular, prefabricated panel members in contiguous relationship on the beam members with the panel members disposed transversely of and spanning a plurality of beam members, the prefabricated panel members having waterproof upper surfaces and a flexible waterproof flap extending from the waterproof upper surface of at least one edge of each contiguous pair of edges of adjacent panel members, the flap being sealed along its length to the waterproof surface of the panel member to which it is attached to form a continuation of the waterproof surface;

mechanically fastening the opposite edges of the panel members to the underlying beam members to resist upwardly directed wind loads on the panels by means of tension forces developed within the panel member; and

positioning a flexible flap over the mechanically fastened edges and sealing the flexible flap to the adjacent panel member to form a continuous watertight membrane between the watertight surfaces of the adjacent panel members along and over contiguous edges of the panel members which are fastened to the beam members.

6. A method of roof construction comprising:

arranging a multiplicity of rectangular, prefabricated panel members in contiguous relationship on the beam members with the panel members disposed transversely of and spanning a plurality of beam members, the prefabricated panel members having waterproof upper surfaces and flexible waterproof flaps extending from the waterproof upper surface of at least one edge of each contiguous pair of edges of adjacent panel members, the flap being sealed along its length to the waterproof surface of the panel member to which it is attached to form a continuation of the waterproof surface and having one half of a mechanically interlocking and sealing fastener, the other panel having a mating half of the mechanically interlocking and sealing fastener sealed along its length to the waterproof surface of the other of the adjacent panel members;

positioning a flexible flap over the mechanically fastened edges of the panel members and mechanically engaging the halves of the fasteners to form a continuous watertight membrane between the watertight surfaces of the adjacent panel members along and over contiguous edges of the panel members which are fastened to the beam members.

7. A method of roof construction comprising:

arranging a multiplicity of rectangular, prefabricated panel members in contiguous relationship on the beam members with the panel members disposed transversely of and spanning a plurality of beam members, the prefabricated panel members having a waterproof flexible membrane adhered over tension means extending transversely of the panel member, the membrane extending beyond at least one edge of each contiguous pair of edges of adjacent panel members to form a flexible flap;

mechanically fastening the tension means at opposite edges of the panel members to the underlying beam members to resist upwardly directed wind loads on the panels at least partially by means of tension forces developed within the tension means; and

8. A method of roof construction comprising:

arranging a multiplicity of rectangular, prefabricated panel members in contiguous relationship on the beam members with the panel members disposed transversely of and spanning a plurality of beam members, the prefabricated panel members having a layer of insulation and at least one thin sheet of tension material above the insulation, and a flexible waterproof membrane adhered over the upper surface of the-panel member, the membrane extending beyond at least one edge of each contiguous pair of edges of adjacent panel members to form a flexible flap;

mechanically fastening the panel member including the tension means at opposite edges of the panel members to the underlying beam members to resist upwardly directed wind loads on the panels at least partially by means of tension forces developed within the tension means; and

9. A method of roof construction comprising:

erecting a roof supporting substructure;

fabricating a multiplicity of panel members having waterproof upper surfaces and a flexible waterproof flap extending from the waterproof upper surface from at least one edge of at least a portion of the panel members, the flap being sealed along its length to the waterproof surface of the panel member to which it is attached to form a continuation of the waterproof surface;

arranging the multiplicity of panel members in contiguous relationship on the roof supporting structure with at least one flap provided for each pair of contiguous edges;

'UNITED STATES PATENT OFFICE CERTEFICATE OF CORRECTION PATENT NO. 3,914,916

DATED October 28, 1975 INVENTOR( 1 Harold Graves Simpson, Warren Elsworth Scruggs, Richard Clark l N m D l R'c It IS certlfl d t af r rbr ag6ear s ln tl?e 0 e-| ler%|f|ed patent and tnat sald Letters Patent are hereby corrected as shown below:

Column 1, line 38, "trafiice" should be --trafiic-.

(olumn 3, line 37, after "one" delete -of-.

Column 5, line 55, between "and" and "55 insert --member--.

Column 7, line ll, add at end of sentence.

Column 7, line 24, "The" should be --The--.

Column l2, line 33, "abbut" should be --abut--.

Column 14, line 34, between "having" and "transverse" delete --a-.

gigned and Stalcd this thirteenth Day of April1976 [SEAL] A lies I:

RUTH C. MASON C. MARSHALL DANN A Nesting Officer (ummissiuner uj'larer'zrs and Trademarks

Claims

1. A method of roof construction comprising: erecting a roof supporting substructure; arranging a multiplicity of prefabricated roof planks each carrying an integral membrane sheet on said substructure in aligned contiguous relationship to enclose said roof; secruing said planks together at their abutting edges and ends in a lapping joint; securing spaced apart transversely extending strap members across said panels to said substructure and pretensioning said straps; sealing the membrane sheet carried on the planks one to another to seal the roof; and sealing the membrane corner areas adjacent abutting planks.

2. A method of roof construction comprising: erecting a roof supporting substructure; arranging a multiplicity of elongated, prefabricated panel members in contiguous relationship on the roof supporting substructure, the prefabricated panel members having waterproof upper surfaces and a flexible waterproof flap extending from the waterproof upper surface of at least one edge of each contiguous pair of edges of adjacent panel members, the flap being sealed along its length to the waterproof surface of the panel member to which it is attached to form a continuation of the waterproof surface; mechanically fastening the opposite edges of the panel members to the underlying substructure to resist upwardly directed wind loads on the panels by means of tension forces developed in the panel member between the opposite edges; and positioning a flexible flap over the mechanically fastened edges and sealing the flexible flap to the adjacent panel member to form a continuous watertight membrane between the watertight surfaces of the adjacent panel members along the contiguous edges of the panel members.

3. A method of roof construction comprising: erecting a roof supporting substructuRe; arranging a multiplicity of elongated, prefabricated panel members in contiguous relationship on the roof supporting substructure, the prefabricated panel members having waterproof upper surfaces and a flexible waterproof flap extending from the waterproof upper surface of at least one edge of each contiguous pair of edges of adjacent panel members, the flap being sealed along its length to the waterproof surface of the panel member to which it is attached to form a continuation of the waterproof surface, and having one half of a mechanically interlocking and sealing fastener, the other panel having a mating half of the fastener sealed along its length to the waterproof surface of the other of the adjacent panel members; mechanically fastening the opposite edges of the panel members to the underlying substructure to resist upwardly directed wind loads on the panels by means of tension forces developed in the panel member; and positioning a flexible flap over the mechanically fastened edges of the panel members and mechanically engaging the halves of the fasteners to form a continuous watertight membrane between the watertight surfaces of the adjacent panel members along the contiguous edges of the panel members.

4. A method of roof construction comprising: erecting a roof supporting substructure; arranging a multiplicity of elongated, prefabricated panel members in contiguous relationship on the roof supporting substructure, the prefabricated panel members having a waterproof upper surface formed by a flexible waterproof membrane adhered to a tension member having a transverse tensil strength, the membrane extending beyond at least one edge of each contiguous pair of edges of adjacent panel members to form a flap; mechanically fastening the opposite edges of the tension members of the panel to the underlying substructure to resist upwardly directed wind loads on the panels by means of transverse tension forces developed in the tension member between the fastened edges; and positioning a flexible flap over the mechanically fastened edges of the tension member and sealing the flexible flap to the membrane of the adjacent panel member to form a continuous watertight membrane.

5. A method of roof construction comprising: erecting a roof supporting substructure including a plurality of spaced, parallel beam members; arranging a multiplicity of rectangular, prefabricated panel members in contiguous relationship on the beam members with the panel members disposed transversely of and spanning a plurality of beam members, the prefabricated panel members having waterproof upper surfaces and a flexible waterproof flap extending from the waterproof upper surface of at least one edge of each contiguous pair of edges of adjacent panel members, the flap being sealed along its length to the waterproof surface of the panel member to which it is attached to form a continuation of the waterproof surface; mechanically fastening the opposite edges of the panel members to the underlying beam members to resist upwardly directed wind loads on the panels by means of tension forces developed within the panel member; and positioning a flexible flap over the mechanically fastened edges and sealing the flexible flap to the adjacent panel member to form a continuous watertight membrane between the watertight surfaces of the adjacent panel members along and over contiguous edges of the panel members which are fastened to the beam members.

6. A method of roof construction comprising: erecting a roof supporting substructure including a plurality of spaced, parallel beam members; arranging a multiplicity of rectangular, prefabricated panel members in contiguous relationship on the beam members with the panel members disposed transversely of and spanning a plurality of beam members, the prefabricated panel members having waterproof upper surfaces and flexible waterproof flaps extending from the waterproof upper surface of at least oNe edge of each contiguous pair of edges of adjacent panel members, the flap being sealed along its length to the waterproof surface of the panel member to which it is attached to form a continuation of the waterproof surface and having one half of a mechanically interlocking and sealing fastener, the other panel having a mating half of the mechanically interlocking and sealing fastener sealed along its length to the waterproof surface of the other of the adjacent panel members; mechanically fastening the opposite edges of the panel members to the underlying beam members to resist upwardly directed wind loads on the panels by means of tension forces developed within the panel member; and positioning a flexible flap over the mechanically fastened edges of the panel members and mechanically engaging the halves of the fasteners to form a continuous watertight membrane between the watertight surfaces of the adjacent panel members along and over contiguous edges of the panel members which are fastened to the beam members.

7. A method of roof construction comprising: erecting a roof supporting substructure including a plurality of spaced, parallel beam members; arranging a multiplicity of rectangular, prefabricated panel members in contiguous relationship on the beam members with the panel members disposed transversely of and spanning a plurality of beam members, the prefabricated panel members having a waterproof flexible membrane adhered over tension means extending transversely of the panel member, the membrane extending beyond at least one edge of each contiguous pair of edges of adjacent panel members to form a flexible flap; mechanically fastening the tension means at opposite edges of the panel members to the underlying beam members to resist upwardly directed wind loads on the panels at least partially by means of tension forces developed within the tension means; and positioning a flexible flap over the mechanically fastened edges and sealing the flexible flap to the adjacent panel member to form a continuous watertight membrane between the watertight surfaces of the adjacent panel members along and over contiguous edges of the panel members which are fastened to the beam members.

8. A method of roof construction comprising: erecting a roof supporting substructure including a plurality of spaced, parallel beam members; arranging a multiplicity of rectangular, prefabricated panel members in contiguous relationship on the beam members with the panel members disposed transversely of and spanning a plurality of beam members, the prefabricated panel members having a layer of insulation and at least one thin sheet of tension material above the insulation, and a flexible waterproof membrane adhered over the upper surface of the panel member, the membrane extending beyond at least one edge of each contiguous pair of edges of adjacent panel members to form a flexible flap; mechanically fastening the panel member including the tension means at opposite edges of the panel members to the underlying beam members to resist upwardly directed wind loads on the panels at least partially by means of tension forces developed within the tension means; and positioning a flexible flap over the mechanically fastened edges and sealing the flexible flap to the adjacent panel member to form a continuous watertight membrane between the watertight surfaces of the adjacent panel members along and over contiguous edges of the panel members which are fastened to the beam members.

9. A method of roof construction comprising: erecting a roof supporting substructure; fabricating a multiplicity of panel members having waterproof upper surfaces and a flexible waterproof flap extending from the waterproof upper surface from at least one edge of at least a portion of the panel members, the flap being sealed along its length to the waterproof surface of the panel member to which it is attached to form a continuation of the waterproof surface; arranging the multiplicity of panel members in contiguous relationship on the roof supporting structure with at least one flap provided for each pair of contiguous edges; mechanically fastening the opposite edges of the panel members to the underlying substructure to resist upwardly directed wind loads on the panels by means of tension forces developed in the panel member; and positioning a flexible flap over the mechanically fastened edges and sealing the flexible flap to the adjacent panel member to form a continuous watertight membrane between the watertight surfaces of the adjacent panel members along the contiguous edges of the panel members.