Patent Publication Number: US-11035130-B1

Title: Synthetic mechanically attached roof underlayment system

Description:
CLAIM OF PRIORITY 
     The present application claims priority pursuant to 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 62/800,166 filed on Feb. 1, 2019, the contents of which are incorporated herein, by reference, in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention is directed to an underlayment system for a roof structured to increase wind uplift performance through the utilization of a plurality of mechanical fasteners disposed in securing relation to an underlayment material overlying a roof deck or other support structure of the roof. 
     Description of the Related Art 
     In modern day construction, roof covering systems typically include an underlying, supporting deck or like support structure. This underlying support structure is covered by a water proof or leak resistant material that may take various forms. In addition, roof tiles, shingles and like roof coverings are frequently arranged and secured in overlapping relation to one another so as to collectively overlie the roof deck or like underlying roof support structure. Further, the water resistant covering applied to the outer surface of the roof deck serves to secure the plurality of exterior roof tiles directly to the underlying support. Alternatively, other materials such as cement, polyurethane, “poly-foam”, etc. may be utilized to secure or fix an underlying layer of roof tiles, shingles, etc. directly to the outer layer. As such, a roofing system, as generally described above, facilitates a water resistant roofing assembly as well as an outer or exterior, aesthetically pleasing roof covering. 
     However, one constant and continuous area of concern is the structure and procedure utilized in the installation of a roofing system specifically including the roofing tiles or like roof covering materials. In typical fashion, roof tiles may include an underlying tile disposed in laterally adjacent relation to one another and arranged in longitudinally adjacent rows or columns, especially when the roofing system is applied to a slanted or sloped roof. Moreover, an outer array of roof tiles is disposed in overlapping, at least partially supported relation on the underlying tiles. As such, the underlying tiles and outer roof tiles make up the exposed covering of the roof deck or like underlying roofing support structure. 
     In known or conventional roofing systems of the type generally described above, it is recognized in the roofing industry that time, labor and materials associated with installation, including securing the underlayment material to the roof deck or roof support structure is significant and sometimes prohibitive. Moreover, many of the underlayment structures and materials, including those of the type set forth above are expensive to use. 
     Therefore, in order to overcome the problems and disadvantages in the roofing industry, including at least some of those indicated herein, there is a need for an economic, high-performance underlayment system which is structurally operative to enhance wind uplift performance through the utilization of a plurality of mechanical fasteners. The structural features of the proposed and improved mechanical fasteners will serve to minimize a “blanketing effect” in high wind zones. In addition, the utilization of mechanical fasteners with a variety of different underlayment materials facilitate the establishment of a platform for solar thermal tubing and thin-film photovoltaics for use in foam adhered metal and tile roof assemblies. 
     While the use of mechanical fasteners is at least generally known, there is a need in the roofing industry for an improved mechanical fastener. Such an improved mechanical fastener should include structural and operative features, useable in combination with a variety of different or preferred underlayment materials, in a manner which eliminates or significantly reduces the possibility of leakage at their points of attachment with the underlayment material. Yet additional features of a proposed one or more embodiments of a preferred mechanical fastener is the elimination of tearing or ripping of the underlayment material by the mechanical fastener itself. As a result, eliminating such damage helps prevent leakage through the points of penetration or attachment of the mechanical fasteners to the underlayment material. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an economically beneficial, high-performance underlayment system structurally operative to increase wind uplift performance, through the use of a plurality of self-sealing mechanical fasteners. As practically applied, the mechanical fasteners serve to effectively secure a variety of different types of underlayment material in overlying relation to a roof deck or like support for the remainder of the roof structure. As a result, a “blanketing effect” is minimized in high wind zones. In addition, the underlayment system at least partially defines an enhanced platform for solar thermal tubing and thin-film photovoltaics, as used in foam adhered metal roofs and tile roof assemblies. 
     In more specific terms, the underlayment system of the present invention comprises an underlayment material including, but not limited to, synthetic underlayment material, disposed in covering relation to a roof deck or other underlying support for the remainder of the roof structure. At least one, but more practically a plurality of the aforementioned mechanical fasteners are disposed in interconnecting relation to the underlayment material and the roof deck or like roof support. Each of the one or more mechanical fasteners includes an outer plate, an under plate and a connector. When assembled in the aforementioned interconnecting relation, the connector is disposed in penetrating relation through both the outer plate and the under plate and is secured to the roof deck or like support structure, beneath the underlayment material. Non-limiting examples of the synthetic underlayment material may include, but are not limited to, products sold under the trademark Rex Synfelt®, SharkSkin Ultra®, SharkSkin Ultra SA® as well as others and/or a combination thereof. 
     One feature of the present invention is the dimensioning, configuring and overall structuring of the under plate to extend beneath and along an entirety of an outer periphery and/or outer peripheral edge of the outer plate. In such an operative position, the under plate is disposed in segregating relation between the outer peripheral edge of the outer plate and the underlayment material. 
     More specifically, the under plate is disposed beneath and in engagement with an undersurface of the outer plate including an entirety of the outer peripheral edge of the outer plate. Simultaneously, the under plate is disposed in overlying engagement with a correspondingly disposed portion of the underlayment material, which the corresponding connector penetrates. 
     As described in greater detail hereinafter, each and/or different ones of the plurality of mechanical fasteners may be defined by different structural modifications. As such, the outer plate and the under plate may be fixedly secured to one another and be collectively and concurrently disposed in retaining position to the underlayment material as a single, integrated unit. Further, in this embodiment the outer plate and the under plate may include substantially commonly disposed, configured and dimensioned outer peripheral edges. Further, the outer peripheral edge of the under plate is disposed in segregating relation between the underlayment material and the outer peripheral edge of the outer plate. However, structural modifications of this integrated mechanical fastener may also include the outer periphery or outer peripheral edge of the under plate disposed in outwardly extending, surrounding relation to the outer peripheral edge of the outer plate. As should be apparent, this is accomplished by the under plate having a larger diameter, transverse dimension and corresponding periphery than that of the outer plate. 
     Yet another embodiment of the one or more mechanical fasteners comprises the outer plate and the under plate being, at least initially, independent separate structures and at least originally separable from one another. In this embodiment, the connector, due to its concurrent penetration of both the inner and outer plates, serves to mechanically attach them to one another and to the underlayment material. Similar to the above noted integrated mechanical fastener structure, the under plate includes an outer periphery or outer peripheral edge disposed in segregating relation between the outer peripheral edge of the outer plate and the underlayment material. Further, the outer periphery of the under plate may have a greater transverse dimension and corresponding outer periphery, such that the outer peripheral edge thereof may extend outwardly in surrounding relation to an entirety of the outer peripheral edge of the outer plate. 
     Additional structural features of at least one embodiment of the present invention may include the under plate being formed from an at least partially flexible material and being magnetic or capable of being magnetized. The magnetic capabilities of the material of the under plate may be due to the inclusion of a metallic material therein. At least one example of the material from which the under plate is formed may be barium ferrite. In more specific terms at least one embodiment of the under plate comprises a base material of 89% isotropic barium ferrite; 10% chlorinated polyethylene; 0.3% oil and 0.5% of a coupler. 
     In cooperation therewith, the outer plate is formed from an at least partially rigid or semi rigid, yet partially flexible, material such as a metallic material, including tin, aluminum, etc. The degree of rigidity should be such as to facilitate maintenance of the one or more mechanical fasteners in their intended retaining relation to the corresponding portion of the underlayment material being engaged. In cooperation therewith, the under plate may be formed of an at least partially flexible material having structural characteristics which facilitate maintenance of a given mechanical fastener in its intended retaining relation to the corresponding portion of the underlayment system, as set forth above. 
     Yet additional features of each of the preferred embodiments of the one or more mechanical fasteners, as generally described above, include the under plate and the material from which it is formed having self-sealing capabilities at least relative to the connector penetrating therethrough. As used herein, the term “self-sealing” in regards to the material of the under plate is meant to describe the under plate being disposed in sealing engagement with the exterior of the connector passing therethrough. Such sealing engagement prevents or at least significantly restricts the passage of water through the under plate at the point of its engagement with the connector. Such “self-sealing” capabilities of the one or more mechanical fasteners serves to eliminate or significantly reduce the occurrence of leakage through the underlayment at the point or location where the connector of each mechanical fastener penetrates and/or passes through the underlayment material. 
     Supplementary advantages in using a plurality of mechanical fasteners in retaining engagement with an underlayment material, as described herein, include adding to the “texture” of the exposed surface of the underlayment material. More specifically, the exterior or exposed outer surface of synthetic underlayment materials are considered to be relatively smooth. In fact, the “texture” of the exterior surfaces is tested for “tile slippage”, limiting their use to 5/12 and 6/12 slopes. However, even at that slope there is still the possibility that stacked tiles may slip forwardly. The presence of a plurality of spaced apart mechanical fasteners afford a sufficient “texture” to arrest a tile stack from slipping forwardly. Such an increase in texture also facilitates foot traffic over an exposed surface of the underlayment material, by reducing the possibility of slippage. 
     Structural and operative features of the underlayment system of the present invention also include the utilization of a plurality of retainer clips. One or more of the retainer clips is formed of a metallic material and is operatively positioned, by being magnetically connected, concurrently to two of the plurality of mechanical fasteners, which are magnetized as set forth above. When so operatively disposed, the two magnetized mechanical fasteners engaging a corresponding retainer clip are disposed in spaced, adjacent relation to one another. Further, one or more of the retainer clips comprises a substantially U-shaped segment disposed in spaced, overlying relation to the underlayment material. As such, the U-shaped segment is disposed and structured to retain an object or structure specifically including, but not limited to, a portion of a solar tube or conduit in an intended location on the underlayment material. 
     Yet another structural modification contemplated, which is in the intended spirit and scope of the present invention is the separation of the under plate and the outer plate. In more specific terms, the under plate may be attached directly to the underlayment material or at least partially embedded therein. In cooperation there with, the outer layer may be disposed in overlying, substantially aligned relation to the under plate while it is attached to or embedded at least partially within the underlayment material. When cooperatively oriented in this operative position the connector is disposed in penetrating relation to both the exposed outer plate and the under plate, concurrent to the under plate being attached to or at least partially embedded within the underlayment material. In this structural modification the under plate would still include the structural and operative characteristics and features as described hereinafter in the other embodiments of the system of underlayment for a roof structure. It is further contemplated that the under plate may be used independently of the outer plate while still being attached to or at least partially embedded within the underlayment material. 
     These and other objects, features and advantages of the present invention will become clearer when the drawings as well as the detailed description are taken into consideration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a fuller understanding of the nature of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which: 
         FIG. 1  is a perspective view of a prior art mechanical fastener causing damage to at least a portion of the underlayment material with which it is engaged. 
         FIG. 2  is a schematic representation, in exploded form, of one preferred embodiment of a mechanical fastener of the underlayment system of the present invention, positioned for operative disposition relative to a synthetic underlayment material and supporting roof deck or other supporting structure. 
         FIG. 3  is a perspective view of a plurality of the mechanical fasteners of the embodiment of  FIG. 2  disposed in an operative retaining position relative to an underlayment material of a roof structure. 
         FIG. 4  is a side view of another embodiment of a mechanical fastener of the underlayment system of the present invention. 
         FIG. 5  side view of the retaining clip structure which may be operatively included within the underlayment system of the present invention. 
         FIGS. 6A and 6B  are plan views of different synthetic material layers, which when combined, collectively define an underlayment material with which one or more embodiments of the mechanical fastener of the present invention may be utilized. 
         FIGS. 7A and 7B  are plan views of the embodiment of  FIGS. 6A and 6B  respectively, wherein the synthetic layer of  FIG. 7B  is operatively associated with at least a portion of the mechanical fastener of the present invention. 
         FIG. 8  is a plan view of the embodiment of  FIGS. 7A and 7B  interconnected along with a component of the mechanical fastener represented in  FIG. 7B . 
         FIG. 9  is a plan view of the embodiment of  FIG. 8  with an additional component of the mechanical fastener of the present invention used in combination therewith. 
     
    
    
     Like reference numerals refer to like parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As represented in  FIGS. 2-5  the present invention is directed to an underlayment system for a roof structure incorporating at least one but more practically a plurality of mechanical fasteners generally indicated as  10  or  10 ′ operatively positioned to retain a synthetic underlayment material  100  in covering relation to a roof deck or other underlying roof support structure  106 . 
     However, for purposes of clarity in further emphasizing the inventive structural and operative features of the present invention, reference is initially directed to  FIG. 1 , being representative of a conventional, known and/or prior art mechanical fastener generally indicated as  200 , disposed in retaining engagement with underlayment material  100 . More specifically, one or more different types of mechanical fasteners  200  typically include a retaining member  202  connected in overlying engagement with the outer surface of the underlayment material  100 . Securement of the retaining member  202  in its intended retaining position is accomplished by a connector  102  extending therethrough, in penetrating relation to the underlayment material  100 . 
     As also represented in  FIG. 1  the peripheral edge  102 ′ of the conventional mechanical fastener  200  is exposed along at least a majority of its length. Further, the exposed peripheral edge  102 ′ is disposed in at least partial engagement with the underlayment material  100 . As a result, when uplifting forces are placed on the underlayment material  100  the outer peripheral edge  102 ′ may cut into an engaged portion of the underlayment material  100  resulting in a rip, tear, puncture, etc. generally indicated as  300 . Such damage may result in a leakage of water into and through the underlayment material  100  at the damaged section  300 . Such leakage may occur even when the underlayment material  100  is intended to be “waterproof” or otherwise structured to resist water leakage there through. 
     In contrast, the synthetic underlayment system of the present invention, as represented in  FIGS. 2-5 , overcomes the disadvantages and problems of the type set forth above which are currently recognized as a problem by the roofing industry. 
     With primary reference to  FIGS. 2 and 3 , the underlayment system of the present invention incorporates the use of at least one but more practically a plurality of mechanical fasteners  10 . As schematically represented in  FIG. 2 , the one or more mechanical fasteners  10  include an outer plate  12  and an under plate  14  as well as a connector  16 . When assembled, the connector  16  penetrates through both the outer plate  12  and the under plate  14  and concurrently through the underlayment material  100 . The connector  16  may then be concurrently attached, by penetration, to a roof deck or other underlying supporting support structure  106 . In the embodiment of  FIGS. 2 and 3 , the outer plate  12  and the under plate  14  are at least initially independent, separable structures disposed in connected relation to one another by passage of the connector therethrough, into secure engagement with the roof deck or support structure  106 . 
     Accordingly, the assembled, intended operative orientation of the one or more mechanical fasteners  10  are represented  FIG. 3 . As such, practical application includes a plurality of the mechanical fasteners  10  disposed in predetermined, spaced relation to one another and in retaining attachment to the underlayment material  100 . In such an assembled operative disposition, each of the plurality of mechanical fasteners include the under plate  14  disposed in engaging relation to the undersurface of the outer plate  12  concurrently to being disposed in overlying, engaging, retaining relation to the outer surface of the underlayment material  100 . As also indicated, the connector  16  concurrently penetrates through both the outer and under layers  12  and  14 , the underlayment material  100  and into to secure attachment with the roof deck or other support structure  106  of the roof structure. As is also noted, the connector  16  includes a somewhat enlarged head  16 ′ serving to maintain the operative engagement of the outer and under plates  12  and  14  with one another and in overlying retaining engagement to the underlayment material  100 , as clearly represented in  FIGS. 2 and 3 . Further, the connector  16  could be in the form of an elongated nail, screw or other appropriate type connector, sufficient in dimension to penetrate the outer plate  12 , the under plate  14 , the underlayment material  100  and be secured at generally its distal end to the roof deck or other underlying support structure  106 . 
     In order to eliminate or avoid the type of damage  300  represented in the prior art representation of  FIG. 1 , one feature of the mechanical fastener  10  includes the under plate  14  being dimensioned and configured for operative disposition in segregating relation between the outer peripheral edge  13  of the outer plate  12  and the underlayment material  100 . More specifically, the dimension and configuration of the under plate  14  may be such as to extend beneath and along an entirety of the outer peripheral edge  13  of the outer plate  12 , in the aforementioned segregating relation between the outer peripheral edge  13  and the underlayment material  100 , as clearly represented in  FIGS. 2 and 3 . 
     As set forth above, when assembled in retaining engagement with the underlayment material  100  by the penetrating interconnection of the connector  16 , the under plate  14  will be concurrently disposed in engaging relation with the undersurface of the outer plate  12  and the outer, exposed surface of the underlayment material  100 . At the same time, the outer periphery and/or outer peripheral edge  15  of the under plate  14  extends outwardly from and in surrounding relation to the outer peripheral edge  13  of the outer plate  12 . 
     Additional structural features of at least the embodiment of  FIG. 2  include the under plate  14  being formed from an at least partially flexible material and being magnetic or capable of being magnetized. The magnetic capabilities of the material of the under plate  14  may be due to the inclusion of a metallic material. At least one example of a base material from which the under plate  14  is formed may be barium ferrite, as set for the in more detail herein. In cooperation therewith, the outer plate  12  is formed from an at least partially rigid or semi rigid, metallic material, such as, but not limited to, tin, aluminum, etc. The degree of rigidity of the outer plate  12  and/or a combined rigidity of the outer and under plates  12  and  14  should be such as to facilitate maintenance of the one or more mechanical fasteners  10  in their intended retaining engagement with the corresponding portion of the underlayment material  100  including when uplifting forces are exerted on the underlayment material  100 . 
     Accordingly, when the outer plate  12  and the under plate  14  are brought into engagement with one another they will be magnetically, but still removably, connected to one another. Such magnetic capabilities of the mechanical fastener  10  facilitates a rapid and efficient placement of the initially separable outer plate  12  in overlying relation to the under plate  14  prior to the connector  16  being attached or penetrating therethrough. By way of example, a plurality of the under plates  14  can be initially and individually located in a desired location overlying the outer surface of the underlayment material  100 . Thereafter, a plurality of outer plates  12  can be disposed in overlying relation to different ones of the under plates  14 , facilitated by the magnetic attraction therebetween. 
     In order to facilitate application of a plurality of mechanical fasteners  10  in overlying, retaining relation to a corresponding underlayment material  100 , they may be laid out, such as linearly, in a predetermined position prior to the connector  16  being inserted. However, when dealing with a sloped roof there is a recognized tendency for the pre-positioned mechanical fasteners  10 , and or portions thereof to be displaced. Such displacement is particularly prevalent when previously positioned ones of the plurality of mechanical fasteners  10  are nailed or fixed in place, such as when a pneumatic nail gun or similar device is utilized. Accordingly, one additional embodiment of the one or more mechanical fasteners  10  is the inclusion of an adhesive which may be applied to the undersurface of the under plate  14 . Such adhesive will facilitate the preplacement of a plurality of the mechanical fasteners  10  and a maintenance thereof in their intended position even when previously positioned mechanical fasteners  10  are nailed or fixed in place by a pneumatic nail gun or other tool. Such adhesive undersurface may be more specifically defined by a “peel and stick” application, where in the adhesive is additionally covered by a removable peel-away material. 
     When the adhesive embodiment of the mechanical fasteners  10  are utilized in combination with the magnetically attracted outer plate  12  and under plate  14 , the adhesive material need be applied only to the undersurface of the under plate  14 . However, as practically applied, when the magnetic attraction between the outer plate  12  and the under plate  14  is absent, an adhesive material may be applied to the undersurface of both the outer plate  12  and under plate  14 . Therefore when a plurality of the mechanical fasteners  10  are pre-applied, such as in an elongated configuration, the under plate  14  will be adhered to the outer surface of the underlayment material and the outer plate  12  will be adhered to the exposed surface of the under plate. Such adherence will prevent displacement of the pre-positioned mechanical fasteners  10  from their intended location, such as when a pneumatic nail gun or like instrument is used to fasten previously disposed mechanical fasteners  10 , such as on a sloped roof. 
     Placement of either of the above noted embodiments is accomplished in a manner that assures the outer peripheral edge  15  of the under plate  14  is outwardly disposed in surrounding relation to the outer peripheral edge  13  of the outer plate  12 , or is otherwise disposed to maintain a segregated relation between the outer peripheral edge  13  and the exposed portion of the underlayment material  100 , as set forth above. 
     Each and/or different ones of the plurality of mechanical fasteners may be defined by different structural modifications. Accordingly, and with primary reference to  FIG. 4 , another preferred embodiment of the present invention includes a mechanical fastener  10 ′ having different structural features, but at least some similar operational features. More specifically, the mechanical fastener  10 ′ includes an outer plate  12 ′ and an under plate  14 ′ which are fixedly secured to one another. As such, the outer and under plates  12 ′ and  14 ′ may be operatively and collectively disposed in retaining position to the underlayment material  100  as a single, integrated unit. As also represented in  FIG. 4 , the outer plate  12 ′ and the under plate  14 ′ may include substantially commonly dimensioned, disposed and configured outer peripheral edges  13 ′ and  15 ′ respectively. As a result, the outer periphery and/or outer peripheral edge  15 ′ of the under plate  14 ′ is disposed in segregating relation between the underlayment material  100  and the outer peripheral edge  13 ′ of the outer plate  12 ′. However, structural modifications of this integrated mechanical fastener  10 ′ may also include the outer periphery  15 ′ of the under plate  14 ′ having a larger dimension than that of the outer peripheral edge  13 ′ of the outer plate  12 ′, in the manner demonstrated in the embodiment of  FIG. 2 . In this additional structural modification, the outer peripheral edge  15 ′ would be dimensioned and configured to extend outwardly in surrounding relation to the outer peripheral edge  13 ′ of the outer plate  12 ′. As such, the outer peripheral edge  13 ′ of the outer plate  12 ′ would be segregated from contact and/or engagement with the underlayment material  100 . 
     While not represented in  FIG. 4 , it should be apparent that the mechanical fastener  10 ′ is fixedly connected in overlying, retaining relation to the underlayment  100  through the utilization of a connector  16  penetrating through both the outer plate  12 ′ and the under plate  14 ′, in the manner represented in  FIG. 2  and described in detail herein. 
     Due to the fact that the mechanical fastener  10 ′ includes the outer plate  12 ′ and the under plate  14 ′ being fixedly connected, thereby defining an integrated unit, the material from which the under plate  14 ′ is formed may or may not be magnetized and/or include magnetic capabilities. Accordingly, the material from which the under plate  14 ′ is formed may also comprise barium ferrite. 
     Yet additional features of each of the mechanical fasteners  10  and  10 ′ include the under plate  14  and  14 ′ and the material from which they are formed having self-sealing capabilities, at least relative to the connector  16  penetrating therethrough. As used herein, the term “self-sealing” in regards to the under plate  14  and  14 ′ is meant to describe the material thereof being disposed in sealing engagement with the exterior of the connector  16  passing therethrough. Such sealing engagement may be facilitated by the material of the under plate  14  and  14 ′ being at least partially flexible. Further such sealing engagement prevents or at least significantly restricts leakage by restricting the passage of water through the under plate  14  and  14 ′ at the point of its penetrated engagement with the connector  16 . More specifically, the “self-sealing” capabilities of the one or more mechanical fasteners  10  and  10 ′ serve to eliminate or significantly reduce the occurrence of leakage through the underlayment at the point or location where the connector  16  of each mechanical fastener  10  and  10 ′ penetrates and/or passes there through. 
     Yet additional structural and operative features of the underlayment system of the present invention include the utilization of at least one but more practically a plurality of retainer clips  20 . Each of the one or more of the retainer clips  20  is formed of a metallic or other appropriate at least partially rigid and at least partially flexible material. Further, each of the retaining clips  20  includes outwardly extending wings or legs  22  being attached to magnets  24 . As applied, the retaining clip  20  is operatively positioned, by being magnetically connected, concurrently to two of the plurality of mechanical fasteners  10  or  10 ′, which may or may not be magnetized, as set forth above. When so disposed, each of the different magnets  24  are magnetically connected to the outer plate  12  or  12 ′, which as set forth above may be formed from a metallic material. As also represented in  FIG. 5 , the two mechanical fasteners  10  or  10 ′ engaging a corresponding retainer clip  20  are disposed in adjacent but spaced relation to one another. Further, one or more of the retainer clips  20  comprises a substantially open, U-shaped segment  26  disposed in spaced, overlying relation to the underlayment material  100 . As such, the U-shaped segment  26  is disposed and structured to overlie and thereby retain an object or structure specifically including, but not limited to, a portion of a solar tube or conduit  108  in an intended location on the underlayment material  100 . 
     A structural modification of the retainer clip  20 , as represented in  FIG. 5  may be directed to the removal of the magnets  24  attached to the outwardly extending the legs or wings  22 . Rather, the retainer clip  20  and/or the wings  22  may be formed of a metallic material which will be attracted to the magnetized under plate  14  of  14 ′ of the embodiment, through the metallic material outer plate  12  or  12 ′ of the mechanical fastener  10  or  10 ′, as represented and described in detail with regard to  FIGS. 2 and 4 . 
     Yet another structural modification of the mechanical fastener is represented in  FIGS. 6A, 6B  through  FIG. 9  and is generally represented as  10 ″. More specifically, one or more components of the mechanical fastener  10 ″ is embedded in the underlayment material  100 ′. Further the underlayment material  100 ′ may comprise at least two synthetic material layers  110  and  112 . Further, one of the synthetic material layers, such as  112 , may include adhesive characteristics and/or capabilities which facilitate an adhesive attachment of the synthetic layers  110  and  112  in overlying relation to one another, as at least generally represented in  FIGS. 8 and 9 . 
     In addition, these adhesive characteristics or capabilities may facilitate and maintain the placement and/or positioning of at least one, but more practically a plurality of under plates  14  on an initially exposed or outer surface of the synthetic material layer  112 , as represented in  FIG. 7B . Although not specifically represented in  FIGS. 6A, 6B  through  FIG. 9 , once the under plate  14  is so positioned, an outer plate  12  may be disposed in overlying engagement with the under plate  14  in the manner represented in the embodiment of at least  FIG. 2 . As indicated in the above noted embodiments of  FIGS. 2-4 , the under plate  14  may be formed of a magnetic material and/or have magnetic properties, such as by being at least partially formed of a barium ferrite material. These described magnetic properties facilitates the removable but stable attachment of a metallic material outer plate  12  to the exposed, magnetic face or surface of the under plate  14 . 
     With reference to  FIG. 8 , once the outer plate  12  and the under plate  14  are interconnected and positioned in the manner described above, a connector  16  (not shown) may be applied by penetrating through both the outer plate  12  and the under plate  14  and concurrently through the underlayment material layer  112 . The connector  16  may thereafter be concurrently attached, by penetration, to a roof deck or other underlying supporting support structure  106 . 
     Yet another variation of the mechanical fastener  10 ″ is represented in  FIG. 9  is an alternative from that represented in  FIG. 8 . More specifically, the under plate  14  is placed on the exposed face of synthetic material layer  112  in the manner represented  FIG. 7B . Thereafter, the adjoining synthetic material layer  110 , as represented in  FIG. 7A  is placed in overlying, covering relation to the exposed face of the synthetic material layer  112  as well as the under plate  14  disposed thereon and possibly adhered thereto. 
     It is again to be noted that the under plate  14  may have the aforementioned magnetic capabilities and/or characteristics such as, but not limited to, by being at least partially formed of a barium ferrite material. Accordingly, once the synthetic material layer  110  is disposed in covering relation to both the synthetic material layer  112  and the under plate  14 , the magnetic properties associated with the under plate  14  allow the outer plate  12  to be maintained in aligned, overlying relation to the under plate  14 , due to magnetic attraction of the outer plate  12  to the under plate  14 , as represented in  FIG. 9 . Due to the aforementioned magnetic characteristics and/or capabilities of the under plate  14 , the outer plate  12 , being formed of a metallic material, will be magnetically attracted to the under plate  14  even though the synthetic material layer  110  is disposed therebetween. Therefore, in the embodiment of  FIG. 9 , a connector  16  (not shown) may be applied by penetrating through the outer plate  12 , the outermost synthetic material layer  110 , the under plate  14  and concurrently through the underlayment material layer  112 . The connector  16  may then be concurrently attached, by penetration, to a roof deck or other underlying supporting support structure  106 . 
     Since many modifications, variations and changes in detail can be made to the described preferred embodiment of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents.