Patent Grant
8925677
The invention relates to building materials and systems and, in particular, to an acoustical panel for constructing monolithic ceilings and interior walls.
Sound absorption in buildings is commonly achieved with ceiling tiles carried on a suspended grid. Generally, the sound absorbing capacity of the tiles is achieved by material selection and/or characteristics of the room facing surface. Ceiling tile installations have the advantage of affording ready access to the space above the ceiling, but the divisions between the tiles, even when the grid is concealed, remain visible. Architects and interior designers have long sought a monolithic, texture free look in an acoustical ceiling particularly when there is no expected need for access to the space above the ceiling. Ordinary gypsum panel drywall ceiling construction does not achieve a sufficiently high noise reduction coefficient (NRC) that would qualify as acoustical. Perforated gypsum panels may achieve an acceptable NRC level but they are not monolithic in appearance.
The invention resides in the discovery that ordinary gypsum panels, such as drywall sheets, can be modified to construct an acoustical ceiling or wall with a monolithic plain face and surprising acoustical properties. Such panels can achieve an NRC of 0.70 or more.
In accordance with the invention, the gypsum core is made with a multitude of perforations or holes distributed throughout its planar area. The perforations or holes are restricted, preferably with a painted non-woven porous scrim fabric or veil at the front face and, optionally, a non-woven porous acoustical fabric at the back side.
The gypsum panel can be made, for example, by perforating standard sheets of drywall and thereafter covering the perforated sides of the sheet with additional laminated sheets or layers. These perforating and laminating steps can be performed by the original manufacturer of the drywall sheets or by a separate entity independent of the original drywall manufacturer.
Variations in the construction of the gypsum panel are contemplated. Common among these variations is a panel with a perforated gypsum core and with a face covered by a structure that is porous while appearing essentially imperforate to the unaided eye.
The disclosed gypsum-based panels can be installed in the same manner or a like manner as ordinary drywall. For ceiling applications, the acoustical panels of the invention can be screwed to a conventional drywall suspension system of grid tees or “hat channels” carried on black iron channels typically used in commercial applications or they can be attached to wood framing more often used in residential construction. Acoustical walls can be built by attaching the inventive acoustical panels to vertical studs, serving as spaced support elements. It will be seen that the inventive panels can be readily taped and painted like ordinary drywall, using the same or similar materials, equipment, tools and skills, to produce a smooth monolithic ceiling or wall.
Referring now to
Acoustical panels 20 are attached to the lower sides of the grid tees 12, 13 with self-drilling screws 21. The illustrated acoustical panels are 4 ft. by 8 ft. in their planar dimensions, but can be longer, shorter and/or of different width as desired or practical. The size of the panel 20 and spacing of the grid tees 12 and 13, allows the edges of the panel to underlie and be directly attached to a grid tee, assuring that these edges are well supported.
Referring to
Sheets 29, 30 are laminated to both full sides of the perforated drywall sheet thereby at least partially closing both ends of the perforations 28. At a rear side of the drywall, the backer sheet or web 30 is preferably an acoustically absorbent non-woven fabric known in the acoustical ceiling panel art. By way of example, the backer fabric can be that marketed under the trademark SOUNDTEX® by Freudenberg Vliesstoffe KG. It has a nominal thickness of 0.2 to 0.3 mm and a nominal weight of 63 g/m2. Specifically, the main components of this non-woven fabric example are cellulose and E-glass with a synthetic resin binder such as polyacrylate, poly(ethylene-CO-vinylacetate). Alternatively, for example, the backer sheet 30 can be a porous paper layer. The sheet 30 can be provided with a suitable adhesive for binding it to the rear paper side 25 of the modified drywall sheet 22.
At a front side of the drywall sheet 22, a sheet or web in the form of a non-woven fabric scrim layer 29 is attached with a suitable adhesive. The facing layer or sheet 29 is porous; a suitable material for this application is that used commercially as a cover or face for conventional acoustical ceiling panels. An example of this type of veil material is that marketed by Owens Corning Veil Netherlands B.V. under the product code A125 EX-CH02. This scrim fabric comprises hydrated alumina fiberglass filament, polyvinyl alcohol, and acrylate copolymer. The unpainted scrim 29 has a nominal weight of 125 g/m2 and an air porosity, at 100 Pa, of 1900 l/m2 sec. To avoid blocking the face scrim 29, the adhesive can be initially applied to the panel or sheet 22. The facing sheet 29 should be sufficiently robust to withstand field finishing operations described below. It should also be compatible with drywall joint compound or similar material and commercially available paints, typically water-based paints such as that described below.
Other usable veils 29 include the non-woven, glass fiber products marketed by Owens-Corning Veil Netherlands B.V. as A135EX-CY07 (nominal weight 135 g/m2, air porosity at 100 Pa of 1050 l/m2/sec) and A180EX-CX51 (nominal weight 180 g/m2, air porosity at 100 Pa of 600 l/m2/sec). All of the described veils are translucent and are incapable of visually concealing the perforations 28 unless painted or coated with a coating such as disclosed herein.
The panel 20 with other identical panels is hung on the grid 11 in the same manner as ordinary drywall is installed. Similarly, as shown in
After the joint compound 34 has been sanded or sponged smooth, the front sheets 29 and remaining joint compound are painted with a commercially available acoustical paint 31 used for painting acoustical tile. An example of a suitable water-based paint, sometimes referred to as a non-blocking paint, is available from ProCoat Products, Inc. of Holbrook, Me. USA, sold under the trademark ProCoustic. An alternative non-blocking or non-bridging acoustically transparent paint or coating 31 can have the following formulation:
The optimal perlite aggregate particle size distribution for this coating is centered around 10-100 mesh for between 60%-80% of its volume, packing density can range from 6 to 8 lbs/cubic foot. The coating 31 can be applied in two coats at a total of 40 to 160 g/square foot, wet with a coverage of about 80 g/square foot being ideal.
The particulate of this coating formulation can produce a slightly textured appearance equal to that of medium to coarse sandpaper lying between about 30 and about 60 grit (by CAMI and FEPA Standards). This low texture can serve to visually effectively conceal the joints between panels. To improve the uniformity of the finished appearance of the ceiling, the taped joints can be covered with strips of the veil fabric 29, wide enough to cover the joint compound, prior to painting. The paint application should leave as much porosity through the layer 29 as is desired but leave the appearance of an essentially imperforate surface to the unaided eye so that the perforations 28 are not seen. More specifically, the paint or coating 31 should be of a non-bridging or non-blocking type capable of wetting the fibers of the veil 29 but not creating a film that bridges from fiber to fiber of the veil. Alternatively, where high NRC is not necessary, satisfactory results can be obtained by using a conventional primer and a coat of interior latex paint 31 to complete the installation of the ceiling 10. When the term monolithic is used herein, it is to denote that essentially the entire visible surface of a ceiling or wall appears to be a seamless expanse without joints.
A ½ or ⅝ in. drywall-based panel 20, having the described perforation arrangement and front and rear sheets 29, and customary space behind the panel can exhibit NRC values up to and above 0.70, a rating equal to the performance of better-grade acoustical ceiling tile.
Presently, the preferred characteristics of the gypsum-based core 24 are:
Following are airflow characteristics of the backer layer 30 of the non-woven SOUNDTEX® material described above and the face layer 29 of the first non-woven scrim material described above before and after painting with a proprietary acoustical coating and the acoustical ProCoustic coating.
The tables printed below show NRC values for the inventive board and boards of other constructions for comparison purposes. As in the preceding table, unless otherwise noted, the backer is the SOUNDTEX® material and the face is the first scrim identified above.
Test I:
Perforated Panel=⅝ in. FC30 (drywall) with ⅜″ diameter perforations, 16 mm o.c. spacing—27.7% open area
Test II:
Perforated Panel=½ in. Ultralight (drywall) with 6 mm diameter perforations, 15 mm o.c. spacing, 1.5 in. borders—hole pattern=12.6% open area, overall panel=9.6% open area
Test III:
Panel A (small holes)=½ in. Knauf 8/18R with 8 mm. diameter round perforations, 18 mm o.c. spacing & no borders—15.5% open area
Panel B (large holes)=½ in. Knauf 12/25R with 12 mm. diameter round perforations, 25 mm o.c. spacing & no borders—18.1% open area
Panel E of Test I had a heavy manila paper face with a basis weight of 263.50 gm/m2, a caliper of 17.22 mils, a density of 0.60 c/m3 and a porosity of 58.97 seconds. This test sample illustrates that a face, although porous, but with too high an air flow resistivity is unsuitable for use with the invention. Panel BB of Test I indicates that a face with a higher air flow resistivity (see above table) than a painted scrim face can achieve a satisfactory NRC.
The acoustical panel of the invention can be manufactured in additional ways and with different constructions, but maintaining the perforations effectively restricted on at least the face (room) side of a completed panel. For example, where high NRC values are not needed, the rear layer 30 may be omitted. Porous paper may be substituted for either of the non-woven layers 29, 30.
It has been further discovered that NRC can be measurably increased by orienting the perforations obliquely to the plane of the panel. Such a construction is illustrated in
Referring to
A tape 43 made of the same material as the veil 29 can advantageously be used to span the joint or gap 41 between the panels 40. The width of the tape 43 is less than the combined width of the marginal areas 42 of the panels. Where the panel margins 42 uncovered by the veil 29 are 1 inch wide, the veil tape 43 can be, for example, 1¼ inch wide. The tape 43 can be adhered, for example, by the same adhesive used to join the veil 29 to the paper face 23 or with joint compound.
Use of square edge drywall panels 40 and non-shrinking settable joint compound reduces the time and labor in constructing a ceiling or wall of the invention. The spaces between the longitudinal edges of the tape 43 and edges 44 of the panel veils 29 can be filled with joint compound, preferably of the quick-setting, non-shrinking type. The veil 29, 43 covering the panels 40 is then coated, preferably by spraying, with one of the paint or coating materials 31 described above.
The panel 50 is assembled with identical panels to construct a wall, ceiling or like acoustical barrier. Cross joints associated with the edges 52 can be staggered in relation to adjacent panels joined at edges 53. It will be seen that the cantilevered part or edge 52 and 53 of the veil 29 bridges the actual joint existing between the main bodies 51 of adjacent, abutting panels. Prior to placement of a panel 50 that will provide an overlying veil edge 52, 53, marginal areas 54 not covered by the veil 29 of a previously placed panel 50 are coated with a suitable adhesive, such as discussed above. After placement of this next panel 50, its free veil edges 52, 53 can be pressed on the adhesive on the margins 54 of the previously placed panels 50. The offset veil arrangement of the panel 50 can eliminate the labor of taping joints between panels and has the potential of producing joints that are invisible or nearly invisible to the eye of an observer. Only a very small gap, generally equal to the selected small difference in the size of the veil 29 compared to the main body 51, will be present between adjacent edges of the veils of joined panels 50. While the various FIGS. illustrate rectangular panels that are larger in one planar dimension than a perpendicular dimension, it is to be understood that square panels are intended to be covered within the meaning of the term “rectangular”.
It is desirable for aesthetic and performance reasons that a finish coating applied in the field to the installed and taped panels 20 be relatively smooth with little or no texture. With this smooth finish requirement, it can be difficult to conceal the end joints between panels 20 particularly in a ceiling where glancing light rays are especially revealing. A further constraint is a need to limit the width of the joint compound at a joint so that the sound absorbing face area of the panels 20 is not significantly covered by joint compound and thereby diminished in performance. Ordinary commercially available drywall presents a particularly difficult problem where the ends of the panels are devoid of a taper. It is customary to produce drywall sheets (wall board) with a taper along their long edges but not on the short edges. When drywall panels are abutted end-to-end, they form at their short non-tapered edges what is known in the industry as a “butt joint”. In practice, it is impossible to conceal a taped butt joint in a narrow pattern of joint compound with a no or low texture finish coat. In one aspect of the invention, the drywall panels are modified at their butt joint ends to provide a depression at the outer face associated with the veil 29 for reception of joint tape 35 and joint compound 34. Several alternative constructions are contemplated. Acoustical panels illustrated in
One manner of affording a taper at butt ends 71 of a panel 120 is by permanently compressing both ends of the panel to form a narrow depression or taper 72 along the length of the butt end. This compression is essentially limited to the gypsum core 24 which as originally produced has an air content enabling it to be compressed. The compressed gypsum core 24 at the depression or taper 72 has a corresponding increase in density relative to the remainder of the gypsum in the core. The step of permanently compressing the butt ends 71 of the panel 120 can be done when or after the veil 29 is laminated to the paper face 23 or simultaneously in a machine when perforations or apertures 28 are punched, drilled, or otherwise formed in the panel 120.
Another production manner of forming a tapered geometry at the front face of the panel 20 at the butt end 71 is to machine away or otherwise remove some of the gypsum core beneath the front paper face 23, in the manner of a rabbet or kerf extending inwardly from the butt end, and adhering the paper and any gypsum attached thereto onto the undisturbed underlying zone of the gypsum core 24 at the rabbet or kerf.
An alternative manner of establishing an inwardly tapering face surface adjacent the butt end 71 of a gypsum drywall based acoustical panel 320 is illustrated in
Drywall panels used to form the acoustic panels of the invention may be originally produced by pressing the gypsum core 24 and paper face 23 as the gypsum sets in its di-hydrate state at the area that will ultimately be cut into butt ends on the drywall production line.
Acoustical panels like those described in connection with
The marginal face area 56 (
An alternative approach to reduce or eliminate swelling of the front paper face 23 is the use of a low water absorption manila paper or other type of waterproof paper made with special coatings and fibers that render the face sheet water-resistant.
By marginal areas 57 of the panel 22 it is meant those areas, which may be tapered, that are intended or expected to be coated with joint compound to conceal a joint formed between edges of adjacent panels. The non-swelling water-resistant panels described herein, typically, have the same through hole pattern described hereinabove as well as the same suitably adhered non-woven veil outer face layer 29 and non-woven rear layer 30.
An alternative gypsum board construction is illustrated in
Layers 63 facing the gypsum core 62 of the board 61 are a non-woven fiberglass mat impregnated with acrylic resin, being about 0.033 inch thick. These layers 63 are highly water-resistant, being incapable of absorbing significant moisture, and are essentially impervious to water. Consequently, there is no risk that the layers 63 will absorb water or visibly swell as a result thereof.
The following is a formula for an aggregate-free, non-blocking coating or paint that can be sprayed onto the acoustical panels of the invention to provide a finish, conceal the joints therebetween and hide the perforations 28 that can otherwise show through the veil 29. The coating can be applied in two applications with the first application being lightly sanded.
The fillers include and are not limited to: carbonate (different particle size or morphology), clays, delaminated clays, water wash clay, nepheline syenite, TiO2, mica, talc and other known fillers used in paints.
Typically, joint compound in a finish sanded joint absorbs water to a different extent than the veil 29 and underlying face layer 23 of the gypsum board. This differential absorption rate can result in different drying rates and ultimately a difference in the final appearance of a water based paint overlying the joint areas and the remainder of the acoustical panels. This effect can be reduced by first painting the joint area covered by joint compound with a sealer, such as by using the finish coat/paint locally on the joint area and thereafter priming the whole panel installation. Subsequently, the whole installation is coated with one or two finish paint coats.
A second technique to reduce a difference in the finish paint coat over a joint filled with joint compound and main panel areas is to factory coat the acoustical panel with a primer. After the panel is installed with other panels and their joints are finished, the system is completed with one or two finish paint coats.
The foregoing disclosures, in part, involve modification of a conventional drywall sheet to convert it to the acoustical panel of the invention. However, the inventive acoustical panel can be originally manufactured with perforations in the gypsum core while it is being originally formed or immediately after it is formed and prior to attachment of one or both cover sheets or layers, if any, to its front face and rear side. The perforations, for example, can be cast into the gypsum body. The cross-section of the perforation in the various disclosed embodiments can be accircular when not drilled.
It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.
This application is a continuation-in-part of application Ser. No. 13/832,107, filed Mar. 15, 2013, which is a continuation-in-part of application Ser. No. 13/534,454, filed Jun. 27, 2012.
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| Number | Date | Country | |
|---|---|---|---|
| 20140124291 A1 | May 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13832107 | Mar 2013 | US |
| Child | 14135821 | US | |
| Parent | 13534454 | Jun 2012 | US |
| Child | 13832107 | US |
