Patent Application
20070119108
1. Field of the Invention
The present invention relates to wood frame building construction, and more particularly, to an end cap for surrounding the ends of a flooring or roofing joist or other wood frame member.
2. Related Art
Floor and roof joists are frequently installed by being inserted into hangers that are attached to various vertical structural members. For example, such hangers may be attached to the outer perimeter structure of a floor or roof of a building, such as on top of a concrete foundation wall (preferably attached to the sill plate), or to a rim board. Further, such hangers may be attached to interior floor or roof structure, such as pony walls (again, preferably attached to an interior sill plate) or interior joists. This way, joists may be hung in the hangers to connect to the outer perimeter of the floor or roof, or to connect to each other in a grid of interior joist necessary for larger buildings. As there are many different structures that these hangers may be attached to for the purpose of receiving joists, these many different structures are herein referred as a “mounting plate,” which have the features of a top edge surface and a vertical side surface, wherein the hanger is attached either to the top edge surface and/or the vertical side surface, and wherein the hanger extends down along the vertical side surface to receive the joist. These hangers are well-known in the construction trade, and are typically made of metal. Examples of joist hangers described in patent literature are those in U.S. Pat. No. 770,050 (Dreyer), U.S. Pat. No. 783,807 (Tuteur), U.S. Pat. No. 1,720,104 (Taylor, et al.), U.S. Pat. No. 3,752,512 (Gilb), U.S. Pat. No. 4,411,548 (Tschan), U.S. Pat. No. 4,480,941 (Gibb, et al.), U.S. Pat. No. 4,594,017 (Hills), U.S. Pat. No. 4,802,786 (Yauger, et al.), U.S. Pat. No. 4,893,961 (O'Sullivan, et al.), U.S. Pat. No. 4,920,725 (Gore), U.S. Pat. No. 5,104,252 (Colonias, et al.), U.S. Pat. No. 5,217,317 (Young), U.S. Pat. No. 5,555,694 (Commins), U.S. Pat. No. 5,564,248 (Callies), and U.S. Pat. No. 5,603,580 (Leek, et al.). Various hangers are available commercially under the general names “framing connectors” or “joist hangers,” for example, USP Structural Connectors™ and Simpson Strong Tie™ connectors.
Many joist hangers may be described as metal brackets each having a U-shaped main body with a seat and side members, and two wings that extend from the side members and that have at their ends flanges, which extend generally transverse to the side members for “hooking” across the top of the sill, rim board, board or joist. These hangers are often referred to as hangers with a “top flange” or “top flange mounts,” as the hanger is adapted to be nailed/fastened to the top surface of the mounting plate, with only some having optional nailing into the side surface of the mounting plate.
Other joist hangers attach to only the vertical side surface of the mounting plate, and are often referred to as “face mount” hangers. Attachment of these hangers would rely substantially or entirely on nailing through the side members into the side “face” of the mounting plate, and so these hangers would typically not have flanges at the ends of their side members or would have only small tabs or hooks.
As may be seen in the patent literature, some joist hangers have open back walls, so that a joist received in the hanger may contact the rim board or other mounting plate to which the joist is being connected. Other joist hangers have closed back walls, so that the joist may contact the hanger back wall but not the rim board or other mounting plate to which the joist is being connected. Some joist hangers are adapted for nailing of the joist into the hanger, for example, by nails passing through the hanger and into the joist. Some joist hangers have prongs or ridges to help secure the joist in the hanger.
Joists for floor and roof applications are typically one of two constructions, either having a rectangular profile (traditional boards or beams, with generally flat side surfaces and flat edge surfaces), or an I-shaped profile (“I-joists” having a web connecting two edge flanges that extend out farther than the sides of the web to create an “I” in end view). The bottom edge surface of the joist rests on the seat of the hanger, that is, the bottom of the “U,” and the side surfaces of the joist are retained by the side members of the hanger which laterally support the joist and keep it vertical. As mentioned above, the joist optionally may be fixed to the hanger by means of nails driven through the side members of the hanger into the side surfaces of the joist near the end of the joist. The hanger typically does not have a top wall or other top structure for holding the joist in the hanger, as the flooring structure above the joist and the downward vertical load during construction and after completion of construction serve this purpose.
Even though joists are retained in the hangers by virtue of the joist being hung at both of its ends and bearing a load, and/or by being nailed in the hanger or nailed to the mounting plate, the inventor believes that there is still movement of the joist relative to the hanger, especially when the load on the floor joist changes. For example, during people or animals walking on the floor, or during thermal expansion or contraction, additional or changing loads on the joists are believed to cause squeaking or popping noises in the floor system. This is believed to be caused mainly by 1) movement of the wood joist end surface moving against the wood and/or concrete surface of the mounting plate, if the hanger has an open back, or the wood joist end surface against the hanger, if the hanger has a closed back, 2) the wood joist side or bottom surfaces moving against the metal hangers seat and side members, and/or 3) movement of the wood joist top surface near the joist end moving against the wood surface of the floor panel placed above it. Thus, the sounds are believed to be rubbing of the ends of the wood joist against the surrounding wood surfaces and/or metal hanger surfaces. Currently, some construction workers lay caulking in the joist hangers before the joists are inserted into the hangers, to try to reduce friction between the metal hangers and the joists. However, this technique can be messy, time consuming, and/or ineffective, and the technique may result in the joists not being level in their hangers.
The inventor also believes that there is a need for sound suppression at other locations within conventional wood frame construction. For example, the inventor believes that studs and other vertical wood members often interact with surrounding structure, especially during thermal expansion and contraction, to emit squeaking, popping, and other noise.
Therefore, there is still a need for apparatus and construction techniques that prevent and/or suppress noise resulting from relative movement between wood members and their surroundings in wood frame construction. There is particularly a need for apparatus and methods that prevent or minimize squeaking, popping, and other noise caused by thermal expansion and contraction and/or other forces, while still allowing joists to be set level in conventional metal hangers.
The present invention is an end cap adapted to fit on the end of a joist or other wood frame construction member, to act as a barrier between the construction member and the surrounding structure. The invented end cap helps prevent squeaks, popping, or other noise that occurs when the construction member rubs or slides against surrounding metal, wood, concrete, or other surfaces, for example, because of thermal expansion or contraction and/or other forces placed on the construction member or its surroundings.
In floor and roof construction, the invented end cap may be fit onto the end(s) of a joist that is typically hung in a metal hanger on a generally vertical mounting plate. The joist may be an I-joist or a rectangular beam/joist used in either a flooring or roofing system, for example, with the end cap being especially effective in flooring installations because of the frequent load changes that occur on the floor of the building. In wall construction, the invented end cap may be fit onto the end(s) of a stud or other vertical member, for example.
In a joist-in-hanger application, the end cap surrounds multiple sides of the joist end, and preferably at least four sides, so that the end cap comes between the joist bottom surface (or portion thereof) and the hanger seat, and between the joist side surfaces (or portion thereof) and the hanger side members, and between the joist end surface (or portion thereof) and the side surface of the rim board, sill plate, concrete wall, or other mounting plate on which the joist is being hung. Thus, the end cap surrounds three sides plus the end surface, and, more preferably, four sides plus the end surface, as this helps keep the end cap on the joist with an interference fit. The end cap is typically placed on the joist after cutting the joist to length, just before insertion of the end-capped joist into the metal hanger. The end-cap is preferably not sunk into the concrete wall, rim board, sill plate, or other mounting plate, and is not adapted or positioned to support the weight of (and load on) the joist, except that it is a barrier between the joist end and the hanger which supports said weight of (and load on) the joist.
An object of some embodiments of the invention is to provide a structure between a joist hanger and a joist that will reduce or eliminate noise caused by motion of the joist relative to the hanger and/or surrounding wood. Another object of the preferred embodiment is to provide this structure in an economical device that may be fit as a cover on each end of the joist prior to insertion into the hanger. Another object of the preferred embodiment is to provide an end-cap for a joist, wherein the end cap is not installed directly in or on the concrete wall, rim board, or other mounting plate, but that is laid in the hanger or other receiver that is itself on or in the mounting plate. Another object of the preferred embodiment is to provide an end-cap that is connected to the mounting plate only by means of being in between the joist and the hanger/receiver and optionally secured to the mounting plate by nails or fasteners that preferably pass through a portion of the joist before passing into the mounting plate. In other words, a nail/fastener may be installed through the end cap, into and through the joist, and then into the mounting plate, but preferably not a nail/fastener installed through the end cap and directly into the mounting plate without passing through the joist. An object of other embodiments includes noise reduction/suppression for construction members others than joists, for example, studs and other vertical members and also non-horizontal and non-vertical members such as staircase members.
Referring to the Figures, there are shown several, but not the only, embodiments of the invented end cap. In
The preferred end cap comprises four side walls for covering the top, bottom and side surfaces (or portions thereof) of a joist and an end wall for covering the end surface of the joist. Thus, the side and end walls define a compartment for receiving and preferably completely covering the end of the joist. If an I-joist is being used, as opposed to a rectangular joist, the preferred end cap will preferably have these same walls, with the difference being that only the side surfaces of the I-joist flanges, plus the top surface and bottom surfaces of the flanges will contact and preferably frictionally fit to the side walls and top and bottom walls of the end cap; that is, the I-joist web preferably will not contact and frictionally fit the preferred end cap. Alternative shapes of end caps may be made, for example, specially shaped with an I-shaped profile to fit the profile of the I-beam, but this is less preferred.
The depth of the end cap is preferably the same as, or slightly greater than, the depth of the metal hanger, so that the wooden I-joist is not touching any part of the metal hanger nor any portion of a mounting plate to which the hanger is attached, for example, another I-joist, rim board, foundation wall, or sill plate. Alternatively, and less preferably, the depth of the end cap could be slightly less than the depth of the hanger, and it would still be unlikely for the joist surfaces to touch the hanger surface as long as the end cap stays in place on the joist end.
The end cap and I-joist are connected via an interference fit, wherein there is some interference/friction between at least portions of the end cap and the joist end, but preferably there is no caulking, glue, adhesive, or other tacky substance added between the end cap and the joist. The interference fit is preferably sufficient to keep the end cap on the joist during normal handling at the construction site, which typically consists of handling and listing the joist by grasping or contacting the joist rather than the end cap. The interference fit of the end cap to the joist does not need to be tight enough, and does not need to be supplemented by nails, screws, straps, adhesives, or other additional fasteners, to make the end cap serve as a handle for lifting or transporting the joist. In other words, the end cap is preferably not a handle for the joist, in that it preferably does not extend to have a handle-shaped protrusion from its outer surface and is not necessarily tight enough on the joist to allow a worker to lift the joist solely by grasping and lifting the end cap.
The end-cap-covered joist end is preferably lowered and/or slide horizontally into the hanger, to fit into the hanger with either a clearance, transition, or interference fit between the end cap and the hanger. Most preferably, the hanger frictionally grips at least portions of the end cap and no caulking, glue, adhesive, or other tacky substance is added between the end cap and the hanger. The lack of caulking, glue, adhesive, or other substance (tacky or otherwise) between the end caps (on both ends of the joist) and the hangers prevents inconsistent positioning of the joist ends relative to their respective hangers, and, hence, allows the two joist ends to be set in the hanger in such a way that the joist is level.
Preferably, there should be no flanges, tabs, or other protrusions from the side walls or bottom wall of the cap to interfere with smooth insertion into the hanger or to interfere with the preferred fit wherein the outer surfaces of the hanger side and bottom walls are in contact with the inner surfaces of the hanger along substantially the entire outer surfaces of said side and bottom walls. Further, preferably, there should be no flanges, tabs, or other protrusions from the end wall of the end cap to interfere with smooth insertion into the hanger or to interfere with the preferred fit wherein the joist and end cap are fully inserted into the hanger and the end wall of the end cap contacts the side of the mounting plate (or the back wall of the hanger, if it is a closed-back hanger) along substantially the entire outer surface of the end wall.
Alternatively, there may be end caps and/or hangers that have tabs, ridges, bumps, ribs, or other protrusions to engage the cooperating item. For example, an end cap may have such protrusions on its inner surface(s) to grip a joist, or on its outer surface(s) to grip the hanger. Also, for example, a hanger may have such protrusions on its inner surface(s) to grip the end cap. Or, an end cap and/or hanger may have slots, channels, and/or other recesses adapted to cooperate with protrusions extending from the other. For example, to enhance engagement of the end cap by the hanger, the end cap may have one or ribs that engage one or more slots in the hanger. These scenarios are less preferred, however, because it would mean more complex molding for the end cap.
With the desired fit of end cap on joist end, and end cap-covered joist in the hanger, there is preferably little or no room for the joist to move in the hanger. Some movement is often inevitable, as described above, when the load and movement on the floor changes, however, this typically results from a slight flexing of the joist, which pivots the end of the joist vertically very slightly, for example, a fraction on an inch. Whereas, such movement is sufficient in the prior art to create a squeak or pop, the invented end cap prevents metal to wood contact at the side and bottom surfaces of the joist, and wood to wood contact at the end and top surfaces of the joist, and, hence, reduces or eliminates the squeaking and popping.
Referring specifically to the figures, the end cap 10 is adapted to fit over the end of a joist to prevent the joist from rubbing against the joist hanger 50 and/or surrounding wood or concrete, and, hence, to reduce or eliminate squeaking and popping noises. Because the installation of each end of a joist is typically similar, that is, typically both ends are in hangers, it is preferred that each end of the joist has its own end-cap.
In
As shown in
The end cap may be made of a single material, multiple materials, or mixtures of materials, preferably with the contact surfaces of the end cap (the surfaces that contact the joist or other construction member and the surfaces that contact the hanger, plate, or other surrounding members) having a low coefficient of friction. In
The end cap 10, and especially the contact surfaces as discussed above, are preferably manufactured from plastic, such as polypropylene or polyethylene because of the low coefficient of friction of these materials and their resulting benefits to noise reduction in this setting. Other plastics that may be used are polytetrafluoroethylene (Teflon™)-filled polymers, other materials comprising a film, coating, or powder component of Teflon™, or other plastics/polymers that preferably have coefficients of friction in the range of 0.20 or less, and more preferably 0.15 or less, by ASTM-D 1894 (vs. metal dynamic). Teflon™-filled polymers are known in the injection molding art, and polyethylene comprising Teflon™ powder, for example, is commercially-available for injection molding. Other materials preferably having a low coefficient of friction may be used.
In
The I-joist 150 is made up of top 160 and bottom 170 flanges or “chords” and a web 180 between them. The top chord 160 has a top surface 162, side surfaces 164, and a bottom surface 166 (generally divided in two by the web's attachment to the chord). The bottom chord 170 has a bottom surface 172, side surfaces 174 and a top surface 176 (generally divided in two by the web's attachment to the chord). The I-joist 150 can be any conventional I-joist, such as those available from Boise Cascade (Boise), Trus-Joist (a Weyerhaeuser business), International Paper, NASCOR, Ltd, and other companies.
As shown in
The end cap 10 is fitted over the end 152 of the I-joist 150 so that the end 152 of the I-joist 150 is inserted into the interior space I of the end cap 10. The end cap(s) 10 are preferably fitted on the end(s) 152 of the I-joist 150 prior to placing the I-joist in the joist hanger 50. The I-joists 150 may be transported to construction sites with the end cap(s) 10 already placed on the ends of the I-joists 150.
In the preferred embodiment, the top panel 18 covers top surface 162 of the top chord 160, and bottom panel 14 covers the bottom surface 172 of the bottom chord 170. Upper portions of the side panels 12, 16 cover the top chord side surfaces 164, 164′, and lower portions of the side panels 12, 16 cover the bottom chord side surfaces 174, 174′. Further, the end panel 20 covers the end surface 182 of the I-joist, which end surface 182 is I-shaped. These panels and portions also preferably contact their above-listed, respective surfaces of the I-joist, with some or all of the panels/portions contacting their respective top, bottom, and/or side surfaces tightly enough to constitute a friction fit on the I-joist end. Thus, the end cap 10 is adapted to be friction fit onto the joist end, but also removable, and preferably, therefore, there are no nails, screws, adhesive or other securement means needed to retain the end cap 10 on the end 152 of the I-joist 150 except for the preferred frictional engagement. Therefore, it is preferred that the end cap not be a handle for the joist, that is, that is not be fixed to the joist in such a way that the end cap may be lifted or pulled to lift or pull the joist a significant distance without the joist coming out of the end cap. Additionally, there are no connection means needed to attach the end cap 10 to the hanger 50. The end cap 10 in its preferred form, therefore, does not comprise any flanges, nails, screws, or other extension members extending off of its panels, 14, 16, 18, or 20, and especially not off of the outer surfaces of its panels.
As shown in
As shown in
The end cap 10 may be used in combination with various hangers, including but not limited to, a top flange hanger (50,
Alternatively, the internal space I of the end cap 10 may be configured to resemble the shape of the I-joist, so that the internal space I of the end cap 10 is in the shape of an “I” and the panels defining the I-shaped internal space would contact, and preferably friction fit with all of the exterior surfaces of the I-joist, including the web. This would create a tighter fit between the I-joist and the end cap, however this type of cap would be typically more expensive to manufacture than the rectangular cap and might be more difficult to slide onto the I-joist.
End caps may be made to different dimensions than those suggested by
Alternatively, the end cap may be made without the top panel 18, so that the end cap 10 would consist only of a bottom panel 14, two side panels 12, and an end panel 20. Such an end cap would probably work well for methods wherein the end cap is placed on the joist end just seconds prior to placing the joist end in the hanger (wherein the joist is already near its hangers and has been cut to size), as long as the interference fit of the end cap on the joist were tight enough to prevent the end cap from falling off while inserting the end-cap-covered joist end into the hanger. However, this is a less preferred embodiment, because it would reduce the tendency of the end cap to stay on the joist during handling, and would require the end cap to be in a particular orientation during installation on the joist end prior to being inserted into the hanger (so that the bottom panel of the end cap would rest on the seat of the hanger). An end cap having top, bottom, two sides, and end panels will be extremely quick for construction workers to grab (for example, from a box of end caps) and install, because such an end cap has no top-to-bottom orientation issues and will more surely remain on the joist during handling and insertion.
Although this invention has been described above with reference to particular means, materials and embodiments, it is to be understood that the invention is not limited to these disclosed particulars, but extends instead to all equivalents within the scope of the following claims.
