US20190127974A1

US20190127974A1 - Fire Protective Fastening System for Connecting Non-Load Bearing Wall to Truss

Info

Publication number: US20190127974A1
Application number: US16/170,625
Authority: US
Inventors: Mark A. Dicaire; Mark Penner
Original assignee: OMG Inc
Current assignee: OMG Building Products LLC
Priority date: 2017-11-02
Filing date: 2018-10-25
Publication date: 2019-05-02

Abstract

A fire protective fastening system connects a non-load bearing wall to a truss. A fire protective interface is disposed between a top plate structure and a load bearing member. Fasteners connect between the load bearing member and a non-load bearing member to form a floating connection between the non-load bearing member and the load bearing member. The fire protective medium may take a number of forms including a batt of mineral wool, an intumescent tape and an elongated barrier formed of light gauge metal or spring steel.

Description

BACKGROUND

This disclosure relates generally to devices and techniques for connecting non-load bearing walls to trusses. More particularly, this disclosure relates to connection systems which employ a floating connection to secure a non-load bearing wall to a truss.
In some construction techniques, interior non-load bearing walls are typically framed approximately ½ inch to ¾ inch below the load-bearing components such as, for example, floor joists, floor trusses, roof trusses, etc. The gap allows the load bearing components to deflect under predesigned loads. The non-load bearing walls still require bracing against lateral movement which is the principal object of fastening between the non-load bearing wall and the truss or load bearing structures.
It is well known that if the non-load bearing interior walls are built flush to the underside of the load bearing components, the walls potentially become load bearing or quasi-load bearing. The latter characteristics result in the transfer of load to structural components which, over time, typically result in dips in floors, cracking of finished work and failure of components.
It is also possible that the truss or load bearing structure may deflect upwardly relative to the partition wall. In the latter instance, the wall may be displaced upwardly or otherwise displaced. Consequently, for many installations, it is desirable to implement a floating connection between a non-load bearing wall and a load bearing member by both creating a gap between the top of the non-load bearing wall and the underside of the load bearing member and/or creating a gap at the underside of the wall top plate between the head or flange of the fastener and the underside of the top plate so that the fastener, upon driving, sits proud relative to the underside of the top plate. The phrase “floating connection” refers to a connection which accommodates relative vertical movement between connected structures, but limits movement in the lateral and transverse directions.
One technique for implementing a floating connection between a generally vertical non-load bearing wall and a generally horizontal load bearing member involves implementing the connection by means of a specially configured fastener. A representative fastener is illustrated in FIG. 1. The fastener has a head with a flange-like tapered underside and a shank which has a non-threaded axially extending portion adjacent the flange. The unthreaded portion has slip surface or Teflon™-like coating to facilitate sliding along the unthreaded portion. The fastener has an intermediate knurl and a threaded portion at the distal end. The head and flange have a diameter which is greater than the unthreaded portion.
The knurl upon driving the fastener in the top plate assembly of the non-load bearing interior wall forms a bore which is equal to or slightly greater than the diameter of the unthreaded portion of the fastener. The fastener is driven into the truss or support member so that the thread engages into the support member and the head ultimately engages against the underside of the top plate or projects below the underside of the top plate assembly to form a slight gap, as illustrated in FIG. 2. A slight gap on the order of ½ to ¾ inches is formed below the truss or load bearing member. The unthreaded portion is thus capable of sliding in the bore relative to the non-load bearing member. Naturally, the connecting process is replicated numerous times for a given interior wall panel.
U.S. Pat. No. 9,360,032 discloses a fastener assembly specifically configured to connect a non-load bearing wall to a truss. One fastener assembly embodiment is illustrated in FIG. 3. The fastener assembly comprises a fastener having a head and an axially extending shank which has an unthreaded shank portion and a threaded shank portion adjacent the distal end. A sleeve is retained on the fastener and disposed about the unthreaded shank portion. The sleeve is axially displaceable or slidable along the unthreaded shank portion. The sleeve is typically a plastic member where one end is engageable against the upper end of the threaded portion and the other end against the flange and a tapered neck disposed adjacent the head.
In the fastener assembly of U.S. Pat. No. 9,360,032, the head, flange and neck have a maximum diameter and the thread portion has a major diameter. The sleeve has a generally uniform outside diameter which is less than the maximum diameter of the head flange or neck. The outside diameter is less than the major diameter of the threaded portion. The unthreaded shank portion extends an axial length which is greater than the longitudinal length of the sleeve. The foregoing disclosed fastener assembly can be employed for efficiently implementing a floating connection between a non-load bearing wall and a load bearing component, as illustrated in FIG. 4.
Building codes and safety considerations, for some applications, require fire protection at the interface between the ceiling sheetrock or drywall on each side of the wall. Such a requirement may be an obstacle to use of partition walls with wood components since the drywallers may practically be required to initially install drywall just over portions of partition frames and return to complete the partition walls after the walls have been positioned and the appropriate fire protection barrier has been installed. In a multi-family development, a continuous fire protective barrier layer between the interior wall and the load bearing truss may facilitate compliance with applicable fire protective requirements and allows for implementing efficient floating connections between the non-load bearing wall and the truss.

SUMMARY

Briefly stated, a floating load bearing/non-load bearing assembly, in one preferred form, comprises a load bearing and a non-load bearing member having a top plate structure. A fire protective interface is mounted to the top plate structure and is interposed between the top plate structure and the load bearing member. A fastener having a head, a shank with an unthreaded portion and terminating in a threaded distal tip is driven such that the fastener is driven through the top plate structure and interfaced into the load bearing member so that a floating connection is formed between a non-load bearing member and the load bearing member.
The fire protective interface, in one embodiment, comprises an elongated batt of fire impervious material. The batt may be composed of mineral wool. In another embodiment, the interface comprises an intumescent tape. In another embodiment, the interface comprises an elongated barrier form of light gauge metal or spring steel. The elongated barrier may have a lantern-like cross-section comprising a pair of parallel metal strips separated by an elongated tubular channel.
In one embodiment, a non-load bearing unit has a top plate structure with a top surface and an underside comprising a fire protective barrier attached to the top surface. A fastener having a head, a shank extending from the head and having an unthreaded portion adjacent the head and a threaded distal tip is driven through the top plate structure from the underside. The unthreaded portion extends through the top plate structure and the fire protective barrier.
The fire protective barrier may be an elongated batt composed of mineral wool composite which is resilient and compressible. The barrier may also be in the form of an intumescent tape or an elongated metallic member comprising a pair of parallel strips in the space to form at least one longitudinal channel.
A method for implementing a floating connection between a non-load bearing wall and a load bearing member comprises providing a non-load bearing structure having a top plate structure with an underside and a top side. The method further comprises mounting a fire protective member to the top side and providing a fastener having a head, a shank extending from the head and an unthreaded portion and a distal threaded portion. The method further comprises aligning the non-load bearing member with a truss and driving the fastener through the top plate structure so that the threaded portion engages into the load bearing member and the barrier is interposed between the top plate structure and the load bearing member and a floating connection extends between the wall and the load bearing structure.
In one method embodiment, a method step comprises mounting a fire protective member and attaching a batt of mineral wool composite by means of adhesive. In another method, a fire protective member is mounted to the top side by attaching an intumescent tape. In another embodiment, the method comprises securing an elongated metal barrier to the side.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of the representative fastener employable in the fire protective fastening system;

FIG. 1B is an annotated side view, partly diagrammatic, of the fastener of FIG. 1A;

FIG. 1C is a left side view, partly diagrammatic and partly annotated, of the fastener of FIG. 1B;

FIG. 1D is an enlarged diagrammatic view of an end portion of the fastener of FIG. 1B;

FIG. 2 is a fragmentary perspective view of a prior art fastening system;

FIG. 3 is an annotated side elevational view, partly in diagram form and partly in schematic, of a prior art fastening assembly employable in a fire protective fastening system;

FIG. 4 is an end sectional view, partly in diagram form, illustrating a prior art fastening system employing the fastening assembly of FIG. 3;

FIG. 5 is an enlarged perspective view, partly in diagram and schematic form, of a portion of two trusses, a non-load bearing wall and two possible floating connections incorporating a representative fire protective member which is illustrated schematically;

FIGS. 6A and 6B are respectively a sectional view and a fragmentary perspective view, portions in phantom, illustrating a fire protective floating connection between a non-load bearing wall and a truss for a first fire protection medium;

FIGS. 7A and 7B are respectively a sectional view and a fragmentary perspective view, portions in phantom, illustrating a fire protective floating connection between a non-load bearing wall and a truss for a second fire protection medium; and

FIGS. 8A and 8B are respectively a sectional view and a fragmentary perspective view, portions in phantom, illustrating a fire protective floating connection between a non-load bearing wall and a truss for a third fire protection medium.

DETAILED DESCRIPTION

With reference to the drawings wherein like numerals represent like parts throughout the several figures, a fire protective fastening system for connecting a non-load bearing wall to a truss or structural member is generally designated by the numeral 100 in FIG. 5, 100A in FIGS. 6A and 6B, 100B in FIGS. 7A and 7B and 100C in FIGS. 8A and 8B.
The fastening systems each connect a vertical non-load bearing wall 120 to a horizontal beam of a wood truss 150. The wood truss 150 includes a horizontal beam 160 with an underside surface 162. The beam may flex or be designed to flex under load or flex over time and, in some conditions, may flex or deflect upwardly. The vertical non-load bearing wall 120 includes a top plate structure 130 with an underside 132 and a top side 134. It should be understood, however, when referring to top plate structure in the description below, the top plate structure 130 may in fact be constructed from a single top plate or a pair of top plates. The walls 120 are covered by wallboard 136 which is removed in some of the views to better illustrate the fine protective fastening systems.
A suitable fastener 10 for providing a floating connection for fastening system 100 is illustrated in FIGS. 1A-1D. Fastener 10 has a tapered head 12 with a shank having an unthreaded portion 14, an intermediate knurl 16 and a threaded distal portion 18. The fastener 10 is approximately 6 inches in length. The maximum diameter of the head 12 and unthreaded portion are 0.259 inches and 0.200 inches, respectively. The major diameters of the knurl 14 and threaded tip 18 are 0.240 inches and 0.260 inches, respectively. Naturally, other dimensions are possible.
A fastener assembly 11, also suitable for a floating connection for fastening system 100 comprises fastener 20 with a slidable sleeve 30. A fastener 20 preferably has a six inch axial length includes a hex head 22 which may include an integral retaining washer or flange 23 adjacent a tapered frusto-conical neck 24. Other head retainer flange/neck configurations are possible. An unthreaded cylindrical shank portion axially extends approximately 4 inches from the conical neck 24 adjacent head 22 and integrally connects with a 2 inch threaded distal end portion 28 terminating at a distal tip 29. Naturally, other dimensions are possible.
A slidable sleeve 30 surrounds the unthreaded shank portion 26 and essentially functions to axially slide along the unthreaded shank portion, as indicated by the FIG. 3 arrows. The sleeve is preferably formed from plastic and extends approximately 3 inches with a uniform outer diameter which is less than the outside diameter of the head flange 23. The sleeve is axially retained to the fastener by the opposed ends 32 and 34, respectively, engaging the thread end and in the flange 23 and/or the neck 24. The slidable sleeve 30 is axially linked by the threaded portion of the fastener 20. The external diameter of the sleeve is less than the major diameter of the threaded portion.
It will be appreciated that in one installation method wherein the fastening assembly comprises fasteners 20 and sleeves 30, a bore 31 substantially the same diameter as that of the plastic sleeve 30 or slightly larger, such as approximately 1/32 inch is drilled vertically through the top plate structure. The fastener assembly is inserted into the bore and the head is torqued until the fastener threads into the underside of the support beam of the wood truss as illustrated in FIG. 4. It will be appreciated that the plastic sleeve is received in the bore and the head is torqued so that the flange engages against the underside of the top plate structure or, in an alternative floating connection, the head may be driven to project slightly below the underside of the top plate structure to implement a sliding gap to accommodate upward truss deflection.
With reference to fire protective fastening system 100 of FIG. 5, a representative schematically illustrated, fire protective medium 200 is installed on the top side 134 of the top plate structure 130. The fire protective medium 200 provides an interface between the top plate and the underside of the truss support beam. A fastener 10 or fastener 20 is driven through the top plate structure 130 and threadably engages into the joist or truss 150. The fastener 10, 20 thus provides a floating connection between the wall and the truss while maintaining a fire protective interface between the truss and the wall. Both fastener 10 and fastener 20/sleeve 30 are illustrated in FIG. 5, to illustrate that multiple fasteners 10 and/or multiple fasteners 20 are employed for a given installation. It will be appreciated that the fire protective medium does not interfere with the floating nature of the connection and essentially provides an effective structural gap between the top plate structure 130 and the truss 150.
With reference to FIGS. 6A and 6B for fire preventive fastening system 100A, the protective fire medium 200 is in the form of a mineral wool batt 210. In one embodiment, the batt 210 is pre-cut in an elongated rectilinear form which extends the length of the top plate structure. The batt is resilient and quasi-compressible. Because of the resilience, upon installation, the batt is compressed to form one or more notches 212. The notches 212 are generally complementary to the cross-section of the lower portion of the beam 160 of the truss and are spaced consistent with the spacing between the trusses 150. An adhesive 214 is applied under the pre-cut batt for attaching the batt 210 to the top plate structure.
For this embodiment of fastening system 100A, the installation technique proceeds so that the framer adheres to the mineral wool batt 210 to the top surface 134 of the wall, raises the wall, positions the wall relative to the truss and secures the bottom of the wall. The framer then drives a fastener 10 through the top plate structure 130 and the batt 210 into the beam 160. In the illustrated installation of FIGS. 6A and 6B, the fastener head/flange 12 is spaced from the underside 132 of the top plate structure 130 to form an effective sliding deflection gap. Multiple fasteners 10 are driven at laterally spaced locations through the top plate structure and are engaged into laterally spaced trusses 150 as described to provide secure floating connections between the wall and the support trusses. The resilience of the batt 210 also functions as an effective gap to accommodate deflection of the truss 150 relative to the non-load bearing wall 120.
Alternatively, the head flange 12 may be driven to engage the underside 132 of the top plate structures. In a second alternative embodiment, the fastener may be replaced by fastener assembly 11 of FIG. 3.
In another embodiment illustrated in FIGS. 7A and 7B, the fastening system 100B employs a fire protective medium in the form of an intumescent tape 220. The tape 220 has a layer that expands greatly when exposed to heat and forms a thick, foamy char interface (not illustrated) to prevent heat from transmitting between the sides of the interface. In this embodiment, the tape 220 would typically originate from a roll which is adhered to the top and then cut and sized. One example of a suitable tape is 3M™ Expantrol™ Flexible Intumescent Strip E-FIS manufactured by 3M™ of St. Paul, Minn. Other tapes are also possible. It will be appreciated that the layer would expand and close the gap between the drywall panels 164 of the ceiling and the underside surface 162 of the truss 150 upon installation.
In fire protective fastening system 100C illustrated in FIGS. 8A and 8B, the fire protective medium is in the form of an elongated metal barrier 250. The barrier may be manufactured from light gauge metal or spring steel having a “lantern-like” cross-section. The barrier 250 has elongated parallel metal strips 260 and 262 separated by an elongated tubular channel 270. The barrier 250 is semi-flexible and forms side channels 272, 274 for receiving the end sections of drywall panels 264 and 266. The top layer of the drywall 266 is attached to the barrier 250 to provide a continuous seal with nails and/or adhesive. Again, the barrier 250 would preferably be attached by adhesive 252 to the top side 134 of the wall. Upon driving the fastener 10 through the top plate structure 130 and barrier 250, a floating connection would be obtained with the top plate structure of the wall and the truss and by the intermediate fire protective barrier 250 between the ceiling drywall panels.
While preferred embodiments of the fire protective fastening system have been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and the scope of the present invention.

Claims

1. A floating load bearing/non-load bearing assembly comprising:

a load bearing member;

a non-load bearing member having a top plate structure;

a fire protective interface mounted to said top plate structure and interposed between said top plate structure and said load bearing member; and

a fastener having a head, a shank with an unthreaded portion and terminating in a threaded distal end;

wherein said fastener is driven through said top plate structure and interface into said load bearing member so that a floating connection is formed between said non-load bearing member and said load bearing member.

2. The assembly of claim 1 wherein said fire protective interface comprises an elongated batt of fire impervious material.

3. The assembly of claim 2 wherein said batt is composed of mineral wool.

4. The assembly of claim 1 wherein said interface comprises an intumescent tape.

5. The assembly of claim 1 wherein said interface comprises an elongated barrier formed of light gauge metal or spring steel.

6. The assembly of claim 5 wherein said barrier has a lantern-like cross section comprising a pair of parallel metal strips separated by an elongated tubular channel.

7. A non-load bearing unit having a top plate structure with a top surface and an underside comprising:

a fire protective barrier attached to said top surface; and

a fastener having a head, a shank extending from said head and having an unthreaded portion adjacent said head and having a threaded distal end, wherein said fastener is driven through the top plate structure from the underside and said unthreaded portion extends through said top plate structure and said fire protective barrier.

8. The non-load bearing unit of claim 7 wherein said barrier is an elongated batt composed of a mineral wool composite.

9. The non-load bearing unit of claim 8 wherein said batt is resilient and compressible.

10. The non-load bearing unit of claim 7 wherein said barrier is an intumescent tape.

11. The non-load bearing unit of claim 7 wherein said barrier is an elongated metallic member comprising a pair of parallel strips separated to form at least one longitudinal channel.

12. A method for implementing a floating connection between a non-load bearing wall and a load bearing member comprising:

providing a non-load bearing structure having a top plate structure with an underside and a top side;

mounting a fire protective member to said top side;

providing a fastener having a head, a shank extending from said head having an unthreaded portion and a distal threaded portion;

aligning said non-load bearing member with a truss;

driving said fastener through said top plate structure so that said threaded portion engages into the load bearing member wherein said barrier is interposed between said top plate structure and said load bearing member and a floating connection extends between said wall and said load bearing structure.

13. The method of claim 12 wherein mounting a fire protective member further comprises attaching a batt of mineral wool composite by means of adhesive.

14. The method of claim 12 wherein mounting a fire protective member to said top side further comprises attaching an intumescent tape.

15. The method of claim 12 wherein mounting a fire protective member further comprises securing an elongated metal barrier to said side.