US 20020043037 A1
A fastening system for attaching an expandable building panel or surface covering system to a substrate is provided. The fastening system includes at least one slip clip which, when utilized, allows for longitudinal movement of the building panel, while substantially preventing transverse movement. Typically, a spring clip will be used in combination with the slip clip to apply pressure to the panel, thereby allowing expansion and contraction of the panel in a longitudinal direction while eliminating gaps between the adjacent end-to-end panels. A method of installing building panels using the described fastening system is also provided.
1. A fastening system for an expandable panel comprising:
at least one slip clip.
2. The fastening system of
3. A surface covering system comprising a panel having a fastening flange and a slip clip.
4. The surface covering system of
5. A fastening system for an expandable panel comprising:
at least one slip clip attached to a substrate and cooperating with a longitudinal edge of the expandable panel.
6. The fastening system of
7. The fastening system of
8. The fastening system of
9. A fastening system for an expandable panel comprising:
an expandable panel having a longitudinal edge and a transverse edge;
attachment means, attaching the longitudinal edge of the panel directly to a substrate and permitting relative movement between the panel and the substrate in the longitudinal direction; and
at least one spring clip adjacent the transverse edge of the panel.
10. The fastening system of
11. The fastening system of
12. A fastening system for an expandable panel comprising:
at least one spring clip.
13. The fastening system of
14. The fastening system of
15. A method of attaching expandable panels including one or more flanges to a surface, the method comprising:
attaching one or more slip clips to a substrate, whereby a portion of the slip clip covers a portion of the flange and permits longitudinal movement but not lateral movement of the expandable panel to which the flange is attached.
16. The method of
disposing one or more spring clips along a lateral side of the expandable panel, whereby the spring clip applies compressive force to the panel.
17. The method of
18. The method of
19. The method of
 I. Field of the Invention
 The present invention generally relates to fastening systems for building panels. More specifically, the present invention relates to a fastening system that accommodates the relative expansion and/or contraction between a building panel and the substrate to which the panel is attached.
 II. Background of the Invention
 Wooden ceilings, walls, wainscoting and flooring made of interlocking planks or panels of wood are common in the building industry. So-called “tongue and groove” paneling systems are widely utilized in porches, sunrooms, decks, kitchens, flooring and in other living spaces. These products have traditionally and overwhelmingly been wood-based. A typical wooden tongue and groove wood panel system is represented in FIG. 1 (not to scale). FIG. 1 depicts a typical end view of a known wooden plank or panel system showing how the edge details of the plank may be designed so that the planks can be installed side-by-side. Once joined, the planks may exhibit a V-shaped groove at the junction of the panels.
 Wood products dominate the paneling market, because wood products typically appear more aesthetically pleasing to the consumer. Panels made from plastic materials such as thermoplastic polymers, on the other hand, typically offer higher resistance to moisture, potentially lower cost, lighter weight, and better fire resistance. To gain acceptance and approval from the general public, however, such plastic panels must exhibit a high quality finish. Thus, there is a need to create a high-quality panel with a visual finish that exhibits a level of quality and fit capable of challenging wood paneling. In other words, consumers expect a certain smoothness of finish and quality “look” for the finished product.
 Additionally, materials used for ceilings and other interior finishes must be tested for fire resistance. Since untreated wooden materials are known to support combustion, certain plastic compounds typically perform better in fire resistance testing.
 When paneling systems are employed, for instance, outdoors, the paneling systems are typically exposed to higher humidity and broader ranges of temperature than most indoor applications. There remains a need for ceiling, flooring and wall materials that target such demanding environments. Most commercially available ceiling products are not intended for outdoor or high-humidity applications. It is, however, desirable to provide products that can withstand such extreme environmental conditions, since people are spending less time in basements and more time in sunrooms and on porches, decks and similar spaces, as evidenced by an increase in the construction of such spaces.
 Such demanding environments require that consideration in designing and installing a paneling system take into account the impact of varying temperature and humidity on the choice of construction materials. In a given installation, the substrate to which the panels are attached will expand and contract insignificantly, but the panels will expand and contract significantly along their length as the ambient temperature varies. The temperature coefficient of linear expansion α is defined by equation (1), where L is the length of the specimen in inches, (δL/δT)p is the change in length in inches with respect to the change in temperature in ° C. at a specified constant pressure p,
 For most solids the linear expansion approximates equation (2), where L2 is the expanded length in inches, L1 is the initial length in inches, T2 is the final temperature in ° C. and T1 is the initial temperature in ° C.,
 For rigid PVC based materials, the α value is 10−5 in/in ° C. The calculations utilizing the equations stated above showed that the expansion/contraction of a 40 foot span of building panel would be approximately 1.5 inches.
 If the panels are simply nailed to a surface, warping or sagging can develop. Thus, a system is needed that will provide for the relative thermal expansion and contraction between the substrate and the panels.
 Although plastic panels are known to be less susceptible to these environmental conditions, one characteristic of extruded general purpose polyvinyl chloride (PVC) is its high thermal coefficient of expansion in the axis of the extrusion. In an extruded PVC plank of 12 feet in length, for instance, seasonal temperature variations may cause a length change of up to ½ inch. Known means of fastening of such panels to the surface of a building are not, however, much more advanced than those known for typical wooden systems. In fact, plastic panels are typically attached by nailing or stapling, a flange generally being provided along an edge of the panel for the purpose of attaching the panel to a surface.
 Traditional installation methods for plastic panels generally require nailing or stapling planks or panels side-by-side to cover a desired surface. A known method for installing a typical plank is shown in FIG. 2. A plank 206 is fastened to a surface 200 (e.g. a wall or ceiling) using a fastening flange 204. The flange 204, which is part of the plank 206, is fabricated with a series of fastening slots 202. The plank 206 is held in place temporarily by partially driving nails 201 at two or more points along its length. Alternatively, some plank systems provide elements that allow succeeding rows to be held by fitting to a previously attached run, where it is held by friction (not shown). The plank 206 is subsequently fastened by driving additional nails 203, 205, and 207 through the slots 202 in the flange 204, then completely driving the nails 201.
 In geographical areas subject to wide temperature variations, there are two important installation considerations. First, the fasteners, such as nails 201, 203, 205, and 207 cannot be driven tightly into the mounting surface 200 onto which the plank 206 is being mounted. Fasteners that hold the plank too tightly to the mounting surface 200 will prevent movement necessary to accommodate dimensional changes due to variations in seasonal temperature. Second, the fasteners also must be driven into the center of the nailing slots, as shown, for instance, by nails 203. Fasteners driven into the slots 202 in the manner of nails 205 and/or 207, or in some combination thereof, may also prevent movement of the plank necessary to compensate for thermal expansion and contraction. In addition, if the installation is improper, not allowing the planks freedom to expand and contract along their length, the planks may bow, warp and/or buckle as the plank expands and contracts.
 Further, in some situations, fixed length planks may be too short to fully span the desired space, requiring the installation of planks end to end. If more than one plank is needed to span the length of a ceiling or wall to be covered, it is likely that thermal effects may cause gaps to appear between abutting planks. This is sometimes addressed by using moldings, decorative elements, or other coverings, to hide the butt joints. Consumers, however, prefer the more natural look of unbroken runs of siding and plank materials. Thus, there is a need for installation techniques that eliminate gaps between planks.
 Since plastic building panels, (particularly PVC materials), have high thermal coefficients of expansion, it is important to allow for movement of planks during installation. Thus, there is a need for a fastening system that accommodates thermal effects. As seen above, even when a means of permitting plank movement is supplied, in the form of slotted nailing slots, improper installation practices will mitigate its effectiveness. Thus, there is a need for installation hardware and methods that provide for the movement of the planks.
 The present invention is directed to a system for fastening expandable planks to a surface wherein the planks are allowed to expand and contract without warping, buckling or dislodging of the planks from the mounting surface. The fastening system may include one or more slip clips fastened to the mounting surface and aligned to hold an expandable panel in place, while allowing the panel to expand or contract. The slip clip may include a lower tab which anchors the slip clip to the mounting surface and an upper tab which engages the plank.
 The fastening system may also include one or more spring clips positioned at the end of at least one plank in order to maintain compressive force on the planks as they expand or contract. The spring clip may include at least one arm formed at an angle to the body thereof. One or more spring clips may be used in conjunction with one or more slip clips slotted flanges, netted flanges or other attachment means that allow for movement of a plank.
 These and other aspects of the present invention are set forth in greater detail in the brief description of the drawings and the detailed description of the invention below.
 A full and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures wherein:
FIG. 1 is an end view of a typical tongue and groove planking system according to the prior art.
FIG. 2 is a top view of a fastening system for a building panel according to the prior art.
FIG. 3a is a top view of an embodiment of a slip clip of the fastening system of the present invention.
FIG. 3b is a cross-sectional view of the slip clip of FIG. 3a.
FIG. 4 is a perspective view of a section of a slip clip of the present invention engaging a building panel.
FIG. 5 is a top view of an embodiment of the fastening system of the present invention.
FIG. 6a is a side view of an embodiment of a spring clip of the present invention.
FIG. 6b is a top view of the spring clip of FIG. 6a.
FIG. 7 is a perspective view of an embodiment of the fastening system according to the present invention showing fastening of a building panel to a mounting surface using the slip clip and the spring clip in combination to fasten the panel.
 Reference will now be made in detail to some embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, and is not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the present invention includes such modifications and variations.
 Building panels are provided with a fastening system or mechanism according to the present invention that allow for thermal expansion. The expandable panels may be formed of polyvinyl chloride, or similar polymer or polymeric blend, and have a design element, such as a wood, marble, stone or similar finish. When properly installed, the fastening mechanism accommodates for thermally induced dimensional changes in the building panel. This reduces the chances for buckling, bowing, or warping of the building panel when exposed to a broad range of temperatures.
 The present invention has the advantage of allowing a building panel to move as it expands and contracts. When properly installed, the slip clips firmly hold the building panel in order to inhibit and/or prevent movement thereof both in a direction perpendicular to the long dimension of the panel and a direction perpendicular to the surface of the substrate to which the panel is attached, while allowing longitudinal movement of the panel due to thermal expansion.
 The fastening system of the present invention may use one or more slip clips to hold the fastening flange of a building panel against a mounting surface, while also providing for lateral or longitudinal movement due to expansion or contraction.
 Another feature of the present invention is the added advantage of easy installation. The slip clips are designed so that even when they are firmly attached to the mounting surface, the force applied to the fastening flange is small enough to permit longitudinal movement while being sufficient to prevent transverse movement.
 The present invention also has the advantage of providing flexibility in installation such that less skilled installers may achieve a proper installation. Because the slip clips do not constrain the longitudinal movement of the building panel, it is not necessary for the installer to properly utilize the fastening slots in the fastening flange of the panel. The slip clips need only be aligned along the length of the building panel to line it up with an adjacent panel. Further, a slip clip may be slightly out of line with other slip clips, in at least one direction, without substantially affecting the uniformity of the installed paneling.
 The present invention has yet another advantage of permitting end-to-end installation of building panels without gaps developing between panels and without the use of moldings over the butt joint between the panels.
 The fastening system of the present invention represents an improvement over existing installation methods, since the fasteners that hold the slip clips to the mounting surface can be significantly more firmly fastened without pinching the building panel, and positioning of the slip clip will not constrain longitudinal movement of the building panel. The slip clip of the present invention can be attached to the mounting surface in a variety of ways including, but not limited to, nailing, stapling, riveting, and gluing.
 The present invention includes an apparatus and method of installation directed to solving the problems mentioned above. The fastening system for installing expandable building panels may include two components, a “slip clip” and a “spring clip,” which combine to create a system that enables expandable building panels to accommodate changes in dimension due to thermal effects. As used herein, to suggest that a building panel is “expandable” means that the panel will expand and/or contract with changes in ambient temperature.
 The components of the fastening system according to the present invention are typically made of any of, but are not limited to, the following materials: polymers, copolymers, homopolymers and/or combinations thereof, wood, and metal. Typically, exemplary polymers useful in the present invention include: polyvinylchloride (PVC), polycarbonate, polyacetal, polyamide, and polyethylene. PVC is highly resistant to humidity and has a high temperature coefficient of expansion.
 A slip clip 304 according to the present invention is shown in FIGS. 3a and 3 b. The slip clip 304 may include a lower tab 301, which is fastened to the substrate or mounting surface, and an upper tab 300, which engages the adjacent panel. The upper tab 300 may be displaced from the lower tab 301 by a distance “h” of nominally 0.05 inches. This is slightly more than the nominal thickness of a typical fastening flange 204 (as discussed above). Alternatively, the upper tab 300 may be a spring tab, not shown, which may be attached directly to lower tab 301. Such a spring tab may be curved so as to engage a panel in a similar fashion as upper tab 300, while also directing compressive force to the panel to hold it in place. Additionally, a fastening hole 302 is provided in the lower tab 301. Typically, the hole is nominally 0.063 inches in diameter to accept commonly used mounting nails. It is possible to fabricate slip clips in varying lengths and thicknesses. However, the design disclosed provides a good balance of strength and material use.
 In one embodiment, the slip clip includes a horizontal flat portion that is adapted to abut a surface on which it is to be mounted, a means for attaching the clip to the surface, a vertical portion that extends roughly to the level of a flange on a panel to be adhered to the surface, and a horizontal portion attached to the vertical portion that extends along the surface of a flange to be adjacent to the surface of the surface.
FIG. 4 depicts a perspective view of a section of a building panel 206 showing how the slip clip 304 engages the fastening flange 204 of the building panel. Rather than using the fastening slot 202, the slip clip 304 fits over the edge of the flange 204, retaining the building panel 206 against the mounting surface 200 (not shown), but permitting movement in the longitudinal dimension, (as shown by the arrows in FIG. 5), of the building panel. The slip clip 304 is secured with a fastener 503 using the fastening hole 302. Alternately, the slip clip 304 can be stapled or fastened in whatever manner is appropriate for the mounting surface to be covered.
 Turning to FIG. 5, a fastening flange 204 extends from one edge of the building panel 206 for the purpose of providing a device for attaching the building panel to a mounting surface 200. The fastening flange 204 typically includes at least one slot 202 along its length, and may optionally have a series of slots 202, that have typically provided locations for fastening by a fastener 503, which includes, but is not limited to nails, screws, staples and the like. The slots 202 are nominally about 0.975 inches long and about 0.125 inches wide, on about 1.75 inch centers. The fastening flange 204 typically has the following dimensions: nominally about 0.026 inches thick, while extending from the building panel 206 about 0.53 inches.
 When installing the building panel system, thermal expansion typically is accommodated when the center of each slot 202 is used for fastening the building panel 206 in place. The fastening system of the present invention thus provides for a simpler installation process than previously known.
FIG. 5 depicts an installation scenario similar to that of FIG. 2, with slip clips 304 nailed into the mounting surface 200 instead of using the fastening slots 202 in the fastening flange 204 of the panel. In this case, the tacking nails 201 may still be used to hold the building panel 206 in place until the slip clips 304 are installed. The nails 201 can then be either removed or driven further into the panel, if done in a way that does not prevent the panel from moving longitudinally.
 In addition to the slip clip mounting method of the present invention, a spring clip 704 shown, for instance, in FIG. 6, may be used in combination with the slip clip. Alternatively, the slip clip may be used with slotted flanges, netted flanges or other fastening mechanisms that allow for movement of a building panel relative to the substrate to which it is fastened. In mounting an expandable panel having a longitudinal edge and a transverse edge, attachment means, such as, for example, slip clips, nails flanges or other related means, may be used to attach the longitudinal edge of the panel directly to a substrate, while permitting relative movement between the panel and the substrate in the longitudinal direction. At least one slip clip may be adjacent the transverse edge of the panel. The spring clip is typically a hot dipped galvanized steel spring. Other suitable materials may be used as long as they can provide a spring-type effect and preferably not rust, such as stainless steel and plastic. Typically, the spring clip 704 will be formed with at least one arm 706 formed at an angle to the body 708 of the spring clip. Depending on the choice of materials, as well as the dimensions for construction, the spring clip 704 will be flexible when force is applied to the clip, as shown for instance in FIG. 7. The spring clip 704 is utilized in applications requiring that a building panel 206 or a series of end-to-end panels be pushed in one direction to close one or more gaps, either to secure a single panel or to form a long run of series of panels. When inserted, the spring clip 704 applies end compression or compressive force to the panel, thereby allowing for expansion and contraction of the panel. In one embodiment, a trim piece is used to cover the spring clip. The trim piece can extend beyond the spring clip and cover a portion of the panel, with the proviso that the trim piece permits the panel to expand and compress the spring clip.
 It may be possible to utilize a coil-type spring instead of the angled spring clip 704 depicted herein. However, the angled spring clip is easier and less expensive to fabricate, while still providing the necessary force to prevent gaps from appearing between panels and/or perimeter elements.
FIG. 7 depicts a typical spring clip and slip clip installation. A series of slip clips 304 secure the fastening flange 204 of a building panel 206 to a ceiling, wall or other mounting surface 200 between two perimeter elements 701 and 705 which are perpendicular to the mounting surface and at least as thick as the panel 206. As shown herein, the building panel 206 is butted against perimeter element 705, while the spring clip 704 is installed between the perimeter element 701 and the edge of the building panel 206. As shown in FIG. 6, the end of the arms 706 should be curved to permit the arms to move or slide rather than gouge the perimeter element 701. The ends of the arms 706 may be in the shape of a ball or sphere 707 or have a general curved cross-sectional shape such as shown at 709.
 Having thus described the invention in detail, it should be apparent that various modifications can be made in the present invention without departing from the spirit and scope of the following claims.