GYPSUM STUD WALL SYSTEM WITH HIGH KNOCK FACTOR

BACKGROUND

The present invention relates generally to the construction of interior walls involving the attachment of gypsum wallboard panels to wood or metal framing elements, and more specifically to improved techniques implemented to enhance desired sound transmission through such walls.

Conventional interior walls are often constructed by attaching gypsum wallboard panels to framing members made of wood or U-shaped steel. The frames include horizontally positioned header (upper) and footer (lower) members, respectively secured to the ceiling and floor. Vertically positioned stud members are secured between the headers and footers using fasteners as is well known in the art. Spaces between opposing wallboard panels are optionally filled with bats of insulation.

For US-based customers, there is an expectation by customers that the interior wall needs to be sufficiently sturdy to define the room circumscribed by the walls, and that the wall will support shelving or wall hangings as needed to satisfy the customer's decorating preferences.

Another factor that US-based customers focus on when evaluating interior wall construction is the sound transmission of the wall. In other words, how quiet is the room defined by the interior walls when the doors are closed? An important property of interior walls is the ability of the wall to isolate the individuals within a room defined by the walls from outside noise.

In technical terms, the sound transmission property of an interior wall is quantified by what is known in the industry as an STC value. STC values for interior wall assemblies made of single sheets of ⅝-inch wallboard secured to metal studs range from 38-40 without insulation and 43-44 with insulation in the form of fiberglass bats or the like. Walls made with metal studs have higher (quieter) STC ratings than walls made with wooden studs. Sound rated floors are typically evaluated by ASTM Standard E492 and are rated as to impact insulation class (IIC). The greater the IIC rating, the less impact noise will be transmitted to the area below. Floors may also be rated as to Sound Transmission Class (STC) per ASTM E90. As is the case with wall assemblies, the greater the STC rating, the less airborne sound will be transmitted to the area below. Sound rated floors typically are specified to have an IIC rating of not less than 50 and an STC rating of not less than 50.

It is commonplace for customers of residential or commercial construction in Mexico to focus on the stability of the interior construction in a different way compared with US customers. In Mexico, the focus is more on the solid feel of the interior wall, rather than on the resulting quiet character of the room. Mexican customers are more focused on obtaining sturdy interior walls, and consider structural sturdiness more significant than the sound absorbing qualities. To this end, customers in Mexico often knock on the wall with their knuckles to obtain a sense of the solidity of the relevant wall, with a muffled, solid sound being more favorable to a hollow sound.

Accordingly, there is a need for an interior wall construction system that provides acoustical properties that are acceptable to both US and Mexican customers.

SUMMARY

The above-listed need is met or exceeded by the present interior wall, also referred to as a wall system which features the use of wallboard studs disposed in a wall frame between standard vertical studs. In a preferred embodiment, the wallboard studs are provided in a spacing that enhances a solid feel of the wall when knocked. In a particularly preferred embodiment, the wallboard studs are dimensioned to fill an interior space of the frame defined between first and second wallboard panels. As such, there is a solid connection between the facing wallboard panels and the wallboard studs. In addition, to reduce the transmission of sound through the wall and thus improve the STC values, the present wall system preferably includes at least one sound mat placed between the frame and a substrate. At least a footer of the frame is provided with such a sound mat, however additional frame members, including header and vertical studs are contemplated as being equipped with the sound mat.

Knock test results on the present wall determined that the present configuration provides enhanced acoustic properties of the type preferred by Mexican customers. Further, the incorporation of the sound mat enhances the disruption of trans-wall acoustic energy and thus provides a more suitable wall to US consumer tastes. In testing the present wall system, a knock test index was developed. In the knock test, an acoustically isolated room is created and a test panel is secured to one wall of the room. The test panel is configured to represent the subject wall, with a spacing and arrangement of wallboard studs as described above. A steel ball encased in plastic is connected to the ceiling using a string having a length dimensioned to allow the ball to swing and contact a desired area of the test panel. A nearby microphone is positioned to record the sound generated by the ball impacting the panel.

In one embodiment, a wallboard stud is provided that is fabricated from a gypsum wallboard panel that replaces conventional wood or metal studs. During assembly, the panel is scored on at least one face to have a plurality of parallel score cut lines defining segments. A spacing between the score lines determines the width of the segment. In the present panel, the score lines are spaced so that the panel is rolled from an outer edge, which forms a central core, and following segments are dimensioned so that upon completion of the rolling process, a solid roll of interconnected segments is formed. Adhesive is applied as needed during the rolling process to hold the respective segments together. In a preferred embodiment, a thickness of the rolled-up gypsum stud is in the range of 2.5 inches (6.35 cm), or the width of a track of a top or bottom track.

In an embodiment, the score lines were created by forming 90° V-cuts or score cuts in the conventional wallboard panel, preferably on the “back” or kraft paper face, as opposed to the “front” or finished face. The cuts extend into the board, penetrating and extending through the back face and the core, but leave the face paper intact to enable folding/rolling up. Segments measured in order from the outer edge: 1″ (2.5 cm), 1″ (2.5 cm), 1.5″ (3.8 cm), 1.5″ (3.8 cm), 2.0″ (5.0 cm), 2.0″ (5.0 cm), 2½″ (6.35 cm), 2½″ (6.35 cm), and 2½″ (6.35 cm). Rolling begins at the 1″ edge so that the final, solid rolled stud has a width of 2½″ (6.35 cm).

In an alternate embodiment, a gypsum rolled stud is formed in two main pieces. The first piece is a small, square-shaped insert stud made of rolled gypsum that fits into a central or axial opening of a larger stud tube also made of rolled, scored gypsum. In an embodiment, the smaller, insert stud is formed from four segments measuring 1.5″ (3.8 cm). Linear 90° V-cuts or score cuts are formed in the back face as in the first embodiment. The outer tube is formed by segments formed by 90° V-cuts or score cuts in the back face of the panel and having dimensions of 2.5″ (6.35 cm). The insert tube is inserted into the central axial opening of the larger stud tube. Adhesive is applied as needed to secure the rolled up components in their designated shapes, both the outer tube and the insert tube and the assembled stud.

In still another embodiment, multiple components, meaning outer tubes and smaller insert studs are made from a standard 4 foot×8 foot gypsum wallboard panel. Linear score cuts are made on both the back face and the front or finished face. In some cases, the score cuts are formed through the entire panel. In a preferred embodiment, to create the desired gypsum stud components, the score cut lines are formed in both faces of the panel, so that a clean separation is achieved.

More specifically, an interior wall is provided, including a frame including at least one footer, at least one header, at least one vertical frame member connecting at least one of the at least one footer to at least one of the at least one header, the frame having a first side and a second side, and defining an interior frame space. A first wallboard panel is fastened to the first side of the frame. At least one wallboard stud is secured in the interior frame space, being fastened to the first wallboard panel and being dimensioned to extend from the first side to the second side. A second wallboard panel is fastened to the second side of the frame and to the at least one wallboard stud for creating a continuous acoustic connection between the first wallboard panel and the second wallboard panel.

In a preferred embodiment, the first and second wallboard panels are fastened directly to the corresponding wallboard studs. Also, the frame is preferably made of one of metal channel and wood.

In an embodiment where the frame is made of metal channel, the wallboard studs are configured to have a thickness dimensioned to fill a cavity defined by walls of the metal channel. It is especially preferred that the wallboard studs have a thickness of 2.5 inches.

In an embodiment, the present wall further includes an acoustic mat installed between the frame and a substrate. It is especially preferred that the acoustic mat is disposed between the footer and a substrate. In an embodiment, the acoustic mat is made of polyurethane foam, solid closed cell foam or solid foam rubber.

In analyzing the acoustic properties of the present interior wall, a knock factor ratio was developed. In an embodiment, the knock factor ratio of the present interior wall is 0.8. In an embodiment, the wallboard studs have an on center spacing of one of 12 and 24 inches.

In another embodiment, an interior wall is provided, including a frame including at least one footer, at least one header, at least one vertical frame member connecting at least one of the at least one footer to at least one of the at least one header, the frame having a first side and a second side, and defining an interior frame space. A first wallboard panel is fastened to the first side of the frame. At least one wallboard stud is secured in the interior frame space, being fastened to the first wallboard panel and being dimensioned to extend from the first side to the second side. A second wallboard panel is fastened to the frame and to the at least one wallboard stud for creating a continuous acoustic connection between the first wallboard panel and the second wallboard panel. The frame is made of metal channel and the wallboard studs are dimensioned to have a thickness dimensioned to fill a cavity defined by walls of the metal channel. Further, the wall has a knock factor ratio of 0.8.

In yet another embodiment, a method for constructing an interior wall is provided, including: providing a frame including of at least one footer, at least one header at least one vertical stud connecting the at least one header to the at least one footer, the frame defining a first side, a second side and an interior frame space; attaching at least one wallboard stud in the interior frame space to connect to first and second wallboard panels secured respectively to the first and second sides; measuring a knock factor of the resulting assembled wall; and adjusting at least one of the number and lateral spacing of the at least one wallboard stud in the interior frame space to achieve a knock factor ratio of 0.8.

More specifically, a gypsum stud is provided, including a gypsum wallboard panel having first and second facing sheets sandwiching a core therebetween, a series of cuts formed on at least one of the first and second facing sheets and extending into the core, retaining intact an opposing one of said first and second facing sheets to form a hinge point, the panel being rolled from a first side to a second side into a rolled condition so that a rolled up stud is formed.

In an embodiment, a layer of adhesive is applied to at least one of the first and second facing sheets so that the panel is held in the rolled condition. In an embodiment, the cuts are 90° cuts, and preferably the cuts extend vertically up to but not into the opposite facing sheet from where they begin. In an embodiment, the cuts are made in the following sequence: 1″ (2.5 cm), 1″ (2.5 cm), 1.5″ (3.81 cm), 1.5″ (3.81 cm), 2.0″ (5.0 cm), 2.0″ (5.0 cm), 2½″ (6.35 cm), 2½″ (6.35 cm), 2½″ (6.35 cm). In the previous embodiment, the rolling preferably begins at the 1″ end so that the resulting stud has a width of 2½″ (6.35 cm).

In another embodiment, the wallboard panel is a full-size, standard panel, and said cuts are made into the first and second facing sheets in a specialized pattern to form multiple wallboard studs. In such an embodiment, the cuts are preferably made in multiple groups of the following sequence: 3.8 (1.5 in.), 6.9 (2.7 in.), 3.8 (1.5 in.), 6.9 (2.7 in.), 6.4 (2.5 in.), 6.4 (2.5 in.), 6.4 (2.5 in). In such an embodiment, three gypsum studs, including three tubular outer portions and three insert portions are created from the standard wallboard panel.

In an embodiment, the stud is made of two portions, an outer portion defining a central opening, and an insert portion dimensioned to fit within the central opening. In such an embodiment, the insert portion is formed by creating the cuts in an alternating fashion on the first and second facing sheets.

In still another embodiment, a method of making a gypsum stud is provided, including, providing a gypsum wallboard panel having first and second facing sheets sandwiching a core therebetween; generating a series of cuts formed on at least one of the first and second facing sheets and extending into a core located between the sheets, retaining intact an opposing one of the first and second facing sheets to form a hinge point; and rolling the panel from a first side to a second side into a rolled condition so that a rolled up stud is formed.

In an embodiment, a first spacing of the cuts on the first facing sheet is different from a second spacing of the cuts on the second facing sheet. In an embodiment, the method includes generating the series of cuts to form a first outer portion defining a central opening, and generating the series of cuts to form a second, insert portion dimensioned to fit inside the opening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary side perspective view of a wall constructed according to the present system;

FIG. 1A are perspective views of gypsum wallboard studs used in the wall of FIG. 1;

FIG. 2 is a schematic horizontal cross-section of the wall of FIG. 1;

FIG. 3 is a side elevation of a wall frame according to the present system;

FIG. 4 is a side elevation of the frame of FIG. 3 with wallboard panels secured on one side;

FIG. 5 is a side elevation of the insertion of multiple wallboard studs and that attachment of a second wallboard panel to the present system;

FIG. 6 is a side elevation of the present system showing the second wallboard panel being finished by application of wallboard joint compound;

FIG. 7 is a view of the apparatus used to measure the present wall knock test;

FIG. 8 is a view of a rear side of one of the panels used in FIG. 7 to measure the wall knock test;

FIG. 9 is a graph of knock test results for 3 different sample walls, per Table 1;

FIG. 10 is a graph of knock test results per Table 2;

FIG. 11 is a top view of the present rolled gypsum stud;

FIG. 12 is a vertical cross-section of a gypsum panel scored to obtain the rolled gypsum stud of FIG. 11;

FIG. 13 is a top view of an alternate embodiment of the rolled gypsum stud of FIG. 11;

FIG. 14 is a vertical cross-section of a gypsum panel scored to obtain the rolled gypsum stud of FIG. 13;

FIG. 15 is a top view of another alternate embodiment of the present rolled gypsum stud;

FIG. 16 is a partial exploded view of the rolled gypsum stud of FIG. 15;

FIG. 17 is a vertical cross-section of the components of the rolled gypsum stud of FIG. 13;

FIG. 18 is a top view of still another alternate embodiment of the present rolled stud;

FIG. 19 is a vertical cross-section of a standard gypsum wallboard panel scored to produce multiple studs of the embodiment of FIG. 15 in a single foldable piece;

FIG. 20 is a vertical cross-section of a standard gypsum wallboard panel scored to produce multiple studs of the embodiment of FIGS. 15 and 21; and

FIG. 21 is an exploded view of the present rolled stud of FIG. 18.

DETAILED DESCRIPTION

Referring now to FIGS. 1, 1A, 2 and 3, the present wall, also referred to as a wall system, is generally designated 10 and refers to an interior wall in a residential or commercial building that is not load bearing. The wall 10 is mounted on a substrate 12 such as a poured concrete floor or the like, and reaches to a ceiling 14, which may or may not be finished.

Included in the wall 10 is a frame 16 including at least one footer or base member 18 fastened to the substrate 12 by specialized fasteners as known in the art. The footers 18 usually are installed in 8 foot lengths, and multiple footers are often positioned end-to-end, depending on the size of the wall to be constructed. Also included is at least one header 20 defining an upper margin of the frame 16. Similar to the footer 18, the header 20 is provided in 8 foot lengths and multiple headers are often installed end-to-end. At least one vertical frame member 22 connects the footer 18 to the header and the members 18, 20 and 22 are secured to each other with fasteners such as nails or screws (not shown).

In conventional construction, the vertical frame members 22 are installed at a predetermined spacing, such as 16-inch on center spacing. In the present application, the frame 16 is provided with a first side 24 corresponding to an exterior of a room defined by the wall 10, and a second side 26 corresponding to an interior of the room defined by the wall. An interior frame space 28 is defined by the frame members 18, 20 and 22.

Referring now to FIGS. 2 and 4, a first wallboard panel 30 is secured to the first side 24. Preferably, the panel 30 is a sheet of gypsum wallboard or the like having a 4 by 8 foot dimension and a thickness of ½ inch, ⅝ inch or even 1 inch depending on the application. Other known construction panels used in interior construction are contemplated as the first wallboard panel 30. It will be understood that the first wallboard panel 30 represents a plurality of such panels secured to the frame 16 by fasteners to close off the wall 10 as is known in the art.

A feature of the present wall 10 is that at least one wallboard stud 32 is secured in the interior frame space 28, and is fastened to the frame 16 and to an interior surface 34 of the first wallboard panel 30 using fasteners such as screws or nails. It is preferred that the wallboard stud 32 is directly secured to the first wallboard panel to create a secure connection. As seen in FIG. 1A, in the present application, the wallboard stud 32 is assembled from a plurality of layers or thicknesses 36 of conventional wallboard that has been cut into appropriate lengths, such as 8 feet long, in similar fashion to the vertical frame members 22. The multiple layers 36 are secured into a unitary mass using chemical adhesive or the like. Further, in the preferred embodiment, the wallboard studs 32 have a width of 100 mm, about 4 inches and a thickness of 64 mm, about 2.5 inches. In other words, the wallboard stud 32 has a thickness that extends from the first frame side 24 to the second frame side 26.

While the frame 16 is contemplated as being made either of wood studs or metal [-shaped channel, in a preferred embodiment the frame is made of metal channel and the footer 18 defines an upwardly-projecting U-shape defining a cavity 38 between walls 40. A feature of the wallboard stud 32 is having a thickness that extends between the walls 40, or from the first side 24 to the second side 26, which is considered to be substantially the same dimension.

Referring now to FIGS. 2 and 5, once the wallboard studs 32 are secured to the first wallboard panel 30, a second wallboard panel 42 is fastened to the wallboard studs and also to the other frame members 18, 20, 22 similarly to the first wallboard panel 30. As is the case with the first wallboard panel 30, the second wallboard panel 42 is a sheet of gypsum wallboard or the like having a 4 by 8 foot dimension and a thickness of ½ inch, ⅝ inch or even 1 inch depending on the application. Other known construction panels used in interior construction are contemplated. It will be understood that the first wallboard panel 42 represents a plurality of such panels secured to the frame 16 to close off the wall 10 as is known in the art.

As seen in FIG. 6, once the second wallboard panel 42 is in place, the wall 10 is finished in a conventional manner, using wallboard joint compound 44 to fill the seams between adjacent panels. Upon assembly, the second wallboard panel 42 creates a continuous acoustic connection between the first wallboard panel 30, the wallboard stud 32 and the second wallboard panel.

Referring again to FIGS. 1 and 3 another feature of the present wall 10 is that an acoustic mat 46 is installed between the frame 16 and the substrate 12, more specifically between the footer 18 and the substrate. The purpose of the acoustic mat 46 is to absorb acoustic energy transmitted through the wall 10 by interrupting the flow of sound through the wall. As such, the acoustic mat 46 enhances the STC value of the wall 10. While it is preferred that the acoustic mat 46 is positioned between the footer 18 and the substrate 12, it is also contemplated that the acoustic mat 46 is optionally further be positioned between the frame 16 and the ceiling 14, as well as between vertical frame members 22 and adjacent walls.

In construction, the acoustic mat 46 is preferably made of solid or foam rubber, closed cell foam or neoprene. A preferred mat thickness is between ⅛ inch and ½ inch, with a density of 80-120 lb/ft³. Also the present acoustic mat 46 has a tensile strength of 60 psi minimum, with an elongation of 60% minimum.

Referring now to FIGS. 7 and 8, an effort has been made to quantify the acoustic properties of the wall 10 to better design walls for Mexican customers who typically knock on the wall with their knuckles to gauge a wall's solid structure. The test described below is referred to as the Knock Test. Initially, a room 50 is constructed having a minimum size of 8 ft.×8 ft.×8 ft. Included in the room 50 is a floor 52 with carpet tile, a ceiling 54 made of acoustic tile panels supported by a suitable frame, and a plurality of sound absorptive acoustic panels 56 disposed on surrounding walls 58, 60. A test sample 62 of the subject wall 10 is secured to a test wall mount 64, which is mounted on the wall 60, however the particular wall in the room 50 may vary. The room 50 is configured to isolate outside noises, and care is taken to reduce or eliminate other background noise from HVAC, lighting, plumbing and other sources.

A steel ball 66 of preferably 1.12-1.25 inch diameter is preferably encased in plastic in the preferred form of two layers of nitrile gloves, and is secured to a string 68 mounted to the ceiling 54. The string 68 is tied to the nitrile material and is long enough so that the ball 66, when released, will strike the sample 62. While other dimensions are contemplated, with the string 68 mounted to the ceiling 54 at a distance of 33 inches from the support wall 60, to strike the sample 62, the string has a preferred length of 63 inches. It is contemplated that the string length may vary depending on the application, provided the appropriate location on the test sample 62 is achieved. The sample 62 has a height of 48 inches and is centered on the support 64, preferably at 27 inches from both the floor 52 and from the ceiling 54.

Further, prior to the test, the ball 66 is held in a suspended position by a release fixture 70 to provide consistent results. In the preferred embodiment, the release fixture 70 is a clip connected to one of the ceiling 54 and the wall 58 using a string, but other structures are contemplated including fixed stands or racks. A mount 72 such as a tripod, is placed in the room 50 adjacent the sample 62, and is configured for accommodating a sound level meter microphone 74. Preferably, the microphone 74 has the capability of a Class 1 sound level meter with the ability to measure Leq and Lmax in one-third octave bands and octave bands.

FIG. 8 depicts a rear view of the test sample 62 behind the wall 60. This portion of the sample 62 is designed to simulate an adjacent wall to the wall 10 being tested. As such, a frame 76 is constructed of conventional metal channel material, similar to the frame 16. Wallboard panels 78 cover the exterior of the frame 76, and are sealed at joints with acoustical sealant. Preferably, the wallboard panels 78 extend beyond the frame approximately ⅜ to ½ inch to facilitate a snug fit by the sample 62. The frame 76 is dimensioned to surround the target area receiving the impact of the test ball 66. Also the frame 76 is secured, preferably by acoustical sealant, to a backing wall 80 attached to a rear side 82 of the wall 60. A wallboard panel 84 is positioned between the frame 76 and the backing wall 80. A room 86 serving as the location for the rear of the sample 62 is equipped with sound absorbing materials on the floor 52, ceiling 54 and panels 56 similar to the room 50.

Measurements were taken with the microphone 74 positioned at 4 locations across the face of the test sample 62:

- 1. Mic centered at middle of a cavity between studs 32 of the test specimen 62;
- 2. Mic centered at a middle of the stud 32;
- 3. Mic centered at a middle of the cavity between the stud 32 and a perimeter frame edge defining the sample 62; and
- 4. Mic at 2″ from perimeter frame edge.

In the preferred embodiment, all measurement locations are equidistant from the face of the test sample 62 (approximately 12″ from sample).

Details of the sample 62 are as follows. The sample 62 is affixed to the stiff wall 64, and the back of the sample should also be drywall. Also, the sample 62 should be sealed—air compression from inside the sample cannot travel to outside the sample. This is achieved through the use of acoustical sealant and strong cloth tape, cover screws. A minimum sample size: is 24″ wide by 48″ tall.

Further, in the sample 62, the metal framing is covered with drywall to create a drywall frame around the steel studs to prevent sound energy from breaking into/out of test sample cavity. Screws placement/spacing in the sample 62 should mimic real placement/spacing of screws. A single frame can be used for multiple face samples, but screw holes should not be reused. If a sample 62 is overused, a new frame is built. A control sample is created to ensure repeatability between frames. During the test, the steel ball 66 measured impact should be centered in the middle of the sample, between test specimen 62 framing members.

Data generated by the tests is processed as follows: Lmax data is recorded in one-third octave bands and full octave bands. Lmax results are averaged from all measurements at each mic location. A Knock Factor Ratio is calculated from averaged Lmax results (low frequency sound level divided by high frequency sound level). A high knock factor (more low frequency energy than high frequency energy) correlates to hollow-sounding walls. In contrast, a low knock factor (more high frequency energy than low frequency energy) correlates to solid-sounding walls.

Knock Factor Ratio and STC Comparison of Wall Construction

FIG. 9 and Table 1 below contain data for tested knock factors and STC values for three different sample walls, described below:

- Steel Stud (Control): Wall constructed with 2½″ 25 gauge steel studs spaced 24″ on center and faced with ½″ lightweight gypsum board (fastened to steel studs with screws).
- 2″ Gypsum Stud: Wall constructed with 2″ gypsum studs spaced 12″ on center set in 2½″ perimeter steel track and faced with 1″ gypsum panels. ¼″ thick joint compound applied to both sides of the gypsum studs to make up the ½″ gap between the gypsum studs and 1″ gypsum panels. 1″ gypsum panels fastened to 2″ gypsum studs with screws.
- 2½″ Gypsum Stud: Wall 10 constructed with 2½″ gypsum studs set in 2½″ perimeter steel track and faced with 1″ gypsum panels. 1″ gypsum panels fastened to 2″ gypsum studs with screws.

TABLE 1

Knock Factor Ratio and STC comparison of wall construction

Impact Location
Knock Factor Ratio
STC value

Steel Stud (Control)
1.4
33

2 inch Gypsum stud
0.9
39

2.5 inch Gypsum stud
0.8
42

The Knock Factor Ratio calculated from the knock test data above compares low and high frequency sound levels generated by knocking on the test specimen 62. A high knock factor ratio indicates that the low frequency sound levels generated by the knock exceed the high frequency sound levels generated by the knock—when this is the case, the wall is perceived as sounding hollow. A low knock factor ratio indicates that the high frequency sound levels generated by the knock exceed the low frequency sound levels generated by the knock—when this is the case, the wall is perceived as sounding more solid.

In the comparison above, conventional steel stud cavity walls, indicated by the Steel Stud (Control) curve on the graph, sound hollow when knocked upon, as indicated by the high Knock Factor Ratio. Both the 2″ and 2½″ gypsum stud walls, indicated by the 2″ Gypsum Stud and 2.5″ Gypsum Stud curves on the graph in Table 1, sound solid when knocked upon, as indicated by their lower Knock Factor Ratios, compared to Steel Stud (Control). The 2½″ gypsum stud wall has a lower Knock Factor Ratio than the 2″ gypsum stud wall, indicating that adjusting the size/profile of the gypsum stud and the method of attaching the face gypsum panels to the gypsum studs can affect the Knock Factor. Also, when STC values are considered, the 2 inch and 2½ inch gypsum stud walls have significantly higher values and as such respectively better sound absorption qualities than the control.

Knock Factor Comparison (Stud Spacing)

FIG. 10 and Table 2 reflect knock test results for 2 different sample walls 10. A first wall had 2½″ Gypsum Studs at 12″ on center (o.c.): the wall was constructed with 2½″ gypsum studs spaced 12″ o.c. (on center), set in 2½″ perimeter steel track, and faced with 1″ gypsum panels. The 1″ gypsum panels were fastened to 2½″ gypsum studs with screws. In the other wall tested, 2½″ Gypsum Studs at 24″ on center (o.c.): Wall constructed with 2½″ gypsum studs spaced 24″ o.c., set in 2½″ perimeter steel track, and faced with 1″ gypsum panels. 1″ gypsum panels fastened to 2½″ gypsum studs with screws.

TABLE 2

Knock Factor Comparison

Impact Location
Knock Factor Ratio

2.5″ Gypsum Stud @ 12″ o.c.
0.8

2.5″ Gypsum Stud @ 24″ o.c.
0.9

Knock Factor Ratio: (Avg 50 Hz to 80 Hz)/(Avg 1250 Hz to 2000 Hz)

The Knock Factor Ratio calculated from the knock test data above compares low and high frequency sound levels generated by knocking on the test specimen. A high knock factor ratio indicates that the low frequency sound levels generated by the knock exceed the high frequency sound levels generated by the knock—when this is the case, the wall is perceived as sounding hollow. A low knock factor ratio indicates that the high frequency sound levels generated by the knock exceed the low frequency sound levels generated by the knock—when this is the case, the wall is perceived as sounding more solid.

In the comparison above, from the data of Table 2, it is noted that the 2½″ gypsum stud wall with the wallboard studs 32 spaced 12″ o.c. has a lower Knock Factor Ratio than the 2½″ gypsum stud wall with wallboard studs 32 spaced 24″ o.c., indicating that the distance between gypsum studs can affect the Knock Factor Ratio. This result is expected, since a shorter spacing means that more wallboard studs 32 are found in the wall 10.

Referring now to FIGS. 11 and 12, a first embodiment of an alternate embodiment of the gypsum stud 32 discussed above is generally designated 100. The stud 100 shares properties with the stud 32 in that it is formed from a standard gypsum wallboard panel 102, or a portion of such a panel. Included on the panel 102 is a first facing sheet 104, commonly referred to as the face paper which is finished upon installation in a room, a second facing sheet 106, commonly referred to as the backing paper, which is made of a relatively coarser grade of paper, and a set gypsum core 108 sandwiched between the facing sheets 104, 106 as a unit as is well known in the art. It is contemplated that the thickness of the panel 102 may vary with the application, but standard thicknesses are 0.5 inch (1.27 cm) or ⅝ inch (1.58 cm). Also, a full or standard sized panel 102 has a dimension of 4 feet (1.22M)×8 feet (2.44 M). It is also contemplated that the present stud 100 is made either from standard panels, or segments of such panels, also referred to as dunnage.

Generally, the present gypsum stud 100 is formed in a first embodiment by creating a series of cuts 110, preferably 90° V-shaped cuts, also referred to as score cuts or linear cuts, on at least one of the first and second facing sheets 104, 106 and extending into the core 108, up to and retaining intact an opposing one of the first and second facing sheets (at the end opposite the direction of the cut) to form a hinge point. Thus, the uncut facing sheet 104, 106 enables the panel to be held together and creates a hinge or folding point. It will be understood that the cuts 110 extend a full length of the wallboard panel 102, to provide the resulting stud 100 having a height suitable for use in building frame construction.

Upon forming the cuts 110, the panel is then rolled from a first side to a second side, or in from a first direction to a second direction, so that the panel is folded upon itself by hinge action at the cuts. The resulting rolled stud 100 is useful for wall construction between opposing wallboard panels, and has a preferred width of 2.5 inches (6.3 cm). This dimension also is configured to suitably fit within a channel formed by conventional steel frame members forming top and bottom tracks in a wall frame. Tests have shown that such wallboard studs are comparable in their load-bearing qualifications to standard wooden or steel studs.

Referring now to FIG. 12, the panel 102 is shown with the cuts marked 110A, 110B, 110C, 110D, 110E, 110F, 110G and 110H. As described above, the cuts 110 are preferably 90° V-shaped, which provides a series of right angle folds upon rolling. Note that the cuts 110A-110H do not extend into the first facing sheet 104. Once the cuts 110A-110H are made, a plurality of segments 112, designated 112A-1121 are defined, having axial lengths when viewed from right to left in FIG. 12 of: 1″ (2.5 cm), 1″ (2.5 cm), 1.5″ (3.8 cm), 1.5″ (3.8 cm), 2.0″ (5.0 cm), 2.0″ (5.0 cm), 2½″ (6.3 cm), 2½″ (6.3 cm), and 2½″ (6.3 cm). Preferably a layer of chemical adhesive 114 is applied to the segments on at least one of the first and second facing sheets 104, 106 to retain the panel 102 in the rolled up condition. To assemble the gypsum stud 100, the panel in FIG. 12 is rolled from right to left, or smallest segment to largest. Upon assembly, the stud 10 has the appearance as seen in FIG. 11.

Referring now to FIGS. 13 and 14, a modified version of the present gypsum stud is generally designated 120. Features shared with the stud 100 are designated with identical reference numbers. A main difference of the stud 120 is that it has a rectangular profile of 2.0 inches (5.0 cm)×2.5 inches (6.3 cm), while the stud 100 has a profile of 2.5″ (6.3 cm)×2.5″ (6.3 cm) square. Cuts 110A-110G are made as before, while the segments 122A-122H measure 1″ (2.5 cm), 1″ (2.5 cm), 1.5″ (3.8 cm), 1.5″ (3.8 cm), 2.0″ (5.0 cm), 2.0″ (5.0 cm), 2.5″ (6.3 cm) and 2.0″ (5.0 cm). Adhesive 114 is applied as before, and the direction of rolling is right to left, or starting with the smallest segment to the largest. Upon rolling the stud 120, it has the appearance shown in FIG. 13.

Referring now to FIGS. 15-17, another modified version of the present gypsum stud is generally designated 130. Components shared with the studs 100 and 120 are designated with identical reference numbers. A main feature of the stud 130 it is made of two portions, an outer portion 132 defining a central opening 134, preferably polygonal in shape, and an insert portion 136 dimensioned to fit matingly within the central opening. Both the outer portion 132 and the insert portion 136 are constructed by folding segments of the gypsum panel 102. Preferably, the outer portion 132 has a square shape with 2.5 inch (6.3 cm) sides 138, and the insert portion 136 is also square, having 1.5 inch (3.8 cm) sides 140. As seen in FIG. 16, the insert portion 136 also has an opening 142.

Referring now to FIG. 17, the panels 102 used to make the stud 130 are shown in the cutting position. 90° V-cuts 144A-144C are formed in the panel 102 forming the outer portion 132, and define segments 146A-146D of 2.5 inches long. Also, 90° V-cuts 148A-148C in the panel 102 forming the insert portion 136 define segments 150 A-D of 1.5 inches long. It will be seen that in the studs 100, 120 and 130, the cuts 110, 144 and 148 are all made in the same direction, and the first facing sheet 104 defines the hinge or folding point, which is not cut. Depending on the application, the second facing sheet 106 optionally defines the hinge or folding point. Unlike the other embodiments, in this case since the segments 146, 150 are all the same length, the rolling can start in either direction. Also, as needed, the adhesive 114 is applied. Upon completion of the rolling, the outer portion 132 and the insert portion 136 have the appearance shown in FIG. 16. Then, as assembled, with the insert portion 136 inserted into the outer portion 132, the completed stud 130 is shown in FIG. 15.

Referring now to FIGS. 18 and 21, an alternate embodiment to the stud 130 is generally designated 160. Components shared with the previous embodiments 100, 120, and 130 are designated with identical reference numbers. Both studs 130 and 160 are made of two components, an insert portion 136, 162 and an outer portion 132, 164. A main difference between the embodiments 130 and 160 is that the latter adopts a distinctive cut and folding pattern such that the insert portion 162 lacks the opening 134. In addition, the insert portion 162 is created using a “zig-zag” cutting pattern using cuts 110 alternating on both first and second facing sheets 104, 106. Also, the outer portion 164 is formed with cuts on only one facing sheet 104 or 106, but the segments 166 A-D alternating between 1.5″ (3.8 cm) and 2.7″ (6.9 cm) are formed by folding backwards so that the facing sheet closest to the cut is facing outward. As in the other embodiments, adhesive 114 is applied as needed to maintain the folded shape.

In a preferred embodiment, the insert portion 162 has segments 168A-C of 2.5″ (6.4 cm) formed by cuts 170 A-C (FIG. 19) alternating on the first and second facing sheets 104, 106. Upon assembly, the insert portion 162 is inserted into the central opening 134 of the outer portion 164. Adhesive 114 is applied as needed to maintain the desired shapes. The entire length (as opposed to the height, which is equal to wall frame height) of the stud 160 is 3.7″ (9.4 cm).

Referring now to FIGS. 19 and 20, another feature of the present rolled stud 100, 130, 160 is that multiple studs are optionally manufactured from a single standard wallboard panel 102 dimensioned at 4′×8′ (128 cm×244 cm) depending on the arrangement of the cuts 110. The cuts 110R located adjacent both the first and second facing sheets 104, 106 mark a full cut or cleave through the panel 102, defining three studs 160 generated from a single panel. Moving from left to right, the insert segments 168A-C are rolled first, with the zig-zag cuts 170A-C forming the stacked orientation seen in FIG. 18. Then, as rolling progresses, the outer portion 164 is formed. The segments 166A-D and 168 A-C are thus made in multiple groups of the following sequence: 3.8 (1.5 in.), 6.9 (2.7 in.), 3.8 (1.5 in.), 6.9 (2.7 in.), 6.4 (2.5 in.), 6.4 (2.5 in.), 6.4 (2.5 in.).

In FIG. 19, each stud 160 of the three studs formed from the panel 102 is formed in a single piece, with the insert portion 162 joined to the outer portion 164. In FIG. 20, each of the three studs 160 are created in two pieces, with cuts 110 S cleaving the insert portion 162 from the outer portion 164.

While a particular embodiment of the present interior wall system with high knock factor has been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.

GYPSUM STUD WALL SYSTEM WITH HIGH KNOCK FACTOR

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