Abstract:
A composite roof covering securement element is comprised of an elongated rubber membrane onto which a plastic batten strip is adhesively bonded. The membrane and strip have a range of flexibility which permitts the same to be rolled into a coil for manual prepositioning on a roof and then unrolled to lie flat upon the roof for attachment along the perimeter. When installed the composite element resists shear loads and securely retains the overlying roof covering in place.

Description:
This application is a continuation of application Ser. No. 831,412, filed Feb. 5, 1992, now U.S. Pat. No. 5,309,685. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a composite roof securement element and a method of installing the composite element to secure a roof covering in place on a roof structure. 
     BACKGROUND OF THE INVENTION 
     Examples of prior art in securing coverings to roof structures include U.S. patents: 
     U.S. Pat. No. 4,885,887 
     U.S. Pat. No. 4,932,171 
     U.S. Pat. No. 3,900,102 
     and Canadian patents: 
     1,174,024 
     8,71,960 
     While differing in several respects from each other, the structure and methods disclosed in these patents require extensive time and labor to install. 
     A further consideration is the extent to which a roof perimeter fastening system can withstand the forces imposed by winds passing over the roof and, in particular, the shear forces imposed at angles to the perimeter fastening means. For example, it is common practice to secure the perimeter securement elements to the roof structure with a plurality of spaced screw fasteners driven through respective plates or washers. An example is shown in the above mentioned U.S. Pat. No. 4,932,171 wherein a plurality of spaced screws 23 or 32 is utilized. Clearly, force-resistant stresses are concentrated at the spaced fasteners. 
     In practice, a perimeter securement membrane is positioned on the underlying roof insulation. The plurality of plates or washers are then manually placed on the perimeter membrane at intervals therealong. While the specifications may require that the plates be carefully positioned at a predetermined distance from the wall and at equal distances from each other, the pressures of time or the inexperience of the installers may result in a haphazard pattern not in conformance with the specifications. 
     SUMMARY OF THE INVENTION 
     The present invention provides a pre-assembled composite securement element which has the flexibility to be rolled into a coil for convenient manual positioning on the roof and then so as to lie flat on the roof for attachment by suitable fasteners. No plates or washers are involved, with their attendant requirements to be accurately positioned or creating the problems resulting from inaccurate placement. The pre-assembled composite element insures that the fasteners will be installed at predetermined locations in accordance with the applicable specifications; thereby eliminating the conventional haphazard array of plates and fasteners. 
     The composite securement element includes an elongated (that is, relatively long and narrow) plastic batten strip bonded preferably continuously along its length into connection with an elongated membrane. The continuous bond between the batten strip and membrane enhances the holding strength of the installed securement element. When the roof membrane sheet is glued on top of the securement element, the structure of the batten strip maximizes resistance to shear loads, which are concentrated at the fasteners in the prior art, by distributing the forces along the entire length of the element. Accordingly, the fasteners used with the invention are not the sole resistance to the shear forces. 
     OBJECTS OF THE INVENTION 
     It is a primary object of the present invention to provide a securement element and method of installation which substantially reduces time and labor of installation while providing effective resistance to applied forces. 
     It is another object to provide a roof perimeter securement system wherein the fasteners are attached at predetermined locations thereby eliminating haphazard or non-uniform attachment characteristic of prior systems. 
     It is another object to provide a perimeter securement element which is preassembled at a manufacturing facility wherein tolerances can be closely held to produce a product of higher quality than can be achieved by prior art systems. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various other objects, features, and attendant advantages of the present invention will become more fully appreciated from the following detailed description, when considered in connection with the accompanying drawings, in which like reference characters designate like or corresponding parts throughout the several views, and wherein: 
     FIG. 1 is a fragmentary perspective view of a roof structure employing perimeter securement of the prior art. 
     FIG. 2 is a fragmentary perspective view employing the perimeter securement structure and method of the invention. 
     FIG. 3 is a cross-sectional view of the installed roof system. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIG. 1 a roof structure 10 is disposed adjacent to a parapet wall 12 defining the perimeter of the roof. In practice the roof structure 10 could consist of a variety of well known constructions, but in accordance with the illustrated example, the structure is covered by a layer of pre-formed insulation 14. 
     In accordance with the prior art shown in FIG. 1, the perimeter of the insulation 14 is secured in place by a means and method to be now described. A perimeter membrane 16 of reinforced polymeric material such as ethylene propylene diene rubber (EPDM) is disposed on the insulation 14 adjacent the wall 12 shown. A plurality of plastic or metal plates 18 is manually placed on the membrane 16 at spaced intervals, hopefully in accordance with specifications for the job regarding distance from the wall and from each other. Suitable screw fasteners 20 are then driven through respective plates 18 so as to secure the membrane 16 and insulation 14 to the roof structure 10. 
     Typically, the top layer of the completed roof is a sheet or membrane 22 of non-reinforced EPDM glued to the underlying perimeter membrane 16 and secured to the wall 12 by a so-called termination bar 24 which is secured to the wall 12 by suitable fasteners 26. 
     With the prior art system of FIG. 1, winds blowing over the roof will create so-called shear forces effective on the membrane 22 as shown generally by the arrows A. Since the perimeter membrane 16 is secured by the spaced fasteners 20, the material of the roof membrane 22 above the perimeter membrane 16 will tend to pull and move as depicted generally by the dotted lines extending between the fasteners 20. The forces resisting movement are concentrated at the spaced fasteners and over time can cause enlargement of the holes about the fasteners and induce water leakage as well as peeling of the membrane 22 from the corner and parapet wall 12. 
     The invention is shown in FIG. 2 wherein a composite, pre-assembled perimeter securement element 28 is shown rolled into a coil C disposed adjacent to the wall 12, with an end unrolled along the wall as shown. The element 28 consists of an elastomeric perimeter membrane 30 and a plastic batten strip 32. Preferably, the membrane 30 is a 6&#34; wide strip of EPDM approximately 0.045 inches thick and which may be internally reinforced with a highstrength polyester fabric. Such a membrane is commercially available under the &#34;Rubber Gard&#34; trademark from Firestone Building Products Company of Carmel, Indiana. 
     The plastic batten strip 32 is preferably a flexible oriented plastic strip 1&#34; wide and 0.050&#34; thick manufactured by the Assignee herein in accordance with the formulation and method disclosed in U.S. Pat. No. 4,963,430, the disclosure of which is hereby incorporated by reference. As set forth in U.S. Pat. No. 4,963,430 the composition of the batten strip may be from about 80 to 97% by weight of polyethylene terephthalate and from about 3 to 20% by weight of a polyolefin and wherein the polyolefin may be polypropylene. 
     In accordance with the invention, the batten strip 32 is secured preferably continuously along its length to the membrane 30 by an adhesive 34 applied therebetween. The degree of adhesion is sufficient to insure that the membrane and strip will adhere securely throughout handling, installation and final use. 
     The batten strip 32 is provided with a plurality of fastener-receiving openings 36 drilled or punched therethrough at pre-determined intervals prior to attachment of the strip 32 to the membrane 30. Accordingly when ready for attachment to the roof structure, the composite element 28 can be attached by fasteners 38 driven into the respective openings 36. As an alternative, the strip could be simply marked at the desired spaced intervals whereat the holes could be drilled when the composite securement element is installed on the roof. 
     The method of installing the composite securement element 28 is simple and virtually fool-proof. The coil C is readily manually disposed along the wall 12 over the roof insulation 14 and then unrolled as shown in FIG. 2. The conjoint flexibility of the membrane 30 and strip 32 enables the resulting composite element to lie flat on the insulation 14 for quick and easy attachment to the underlying roof structure 10 by the fasteners 38. The strip 32 is pre-assembled on the membrane 30 a pre-determined distance from the edges of the membrane 30 so that disposing the edge of the membrane against the wall will automatically position the fasteners a pre-determined distance from the wall. 
     After quickly and conveniently installing the securement element 28, it will be understood that the roof membrane 22 of FIG. 1 is installed over the element 28 of FIG. 2 and secured to the wall 12 in the same manner-as shown in detail in FIG. 1. The resulting roof structure is shown in FIG. 3. In practice, the underlying securement element 28 is cleaned with a solvent and an adhesive is then applied onto the element 28 along its length. The membrane 22 is thus secured to the composite element 28 continuously along the perimeter of the roof. The bonded connection of the roof membrane 22 to the relatively stiff and strong batten strip 32 prevents the membrane 22 from moving as depicted by the prior art system of FIG. 1. That is, the shear forces are no longer concentrated at the fasteners. 
     By the foregoing the applicants have created a unique roof perimeter securement system well suited to achieve the objects of the invention. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.