Patent Application
20250198173
The present disclosure relates generally to acoustic isolators and more specifically acoustic isolators used in flooring systems.
Acoustic isolators have historically been used beneath reinforced concrete floors where live loads applied to the reinforced concrete floors were dispersed and supported across the thick concrete floors. The weight of the reinforced concrete floor depressed the acoustic isolators such that the addition of live loads to the reinforced concrete floors had a minimal increase in the deflection of the acoustic isolators.
Modern flooring systems are increasingly being made with Cross Laminated Timber (CLT) panels instead of reinforced concrete floors. CLT panels are prefabricated, solid engineered wood panels which are made of layered lumber boards (usually three, five, or seven) stacked crosswise at 90-degree angles and glued into place. Finger joints and structural adhesive connect the boards, which are typically between ⅝ inch to 2 inches thick. The CLT panels can be manufactured at custom dimensions, although transportation restrictions dictate their length.
With these CLT flooring systems, acoustic isolators are used in conjunction with light structural panels, such as wood panels or noncombustible panels, for example USG STRUCTO-CRETE® panels. These lighter floor membranes do not appreciably depress the acoustic floor isolators. As a result, the acoustic isolators used with CLT flooring systems deflect and move under live loads applied to the CLT floors.
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. 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. Many building codes require an IIC rating of 50 or higher, which is difficult to attain for buildings which utilize CLT for the subfloor. Moreover, even though an IIC rating of 50 meets many building codes, experience has shown that in luxury condominium applications, even floor-ceiling systems having an IIC of 56-57 may not be acceptable because some impact noise is still audible.
Buildings with CLT flooring systems typically will not use gypsum wallboard in the ceiling below the CLT flooring system. This is so that the wood components are exposed for aesthetic purposes. As a result, ceilings within those buildings typically do not have a plenum that aids in absorbing noise coming through the floor and ceiling assembly from above. Without the concealed space within the plenum, conventional CLT flooring systems do not include insulation which absorbs noise from the floor above.
Typically, acoustic floor isolators used with CLT flooring systems are made of materials that are soft and have low compressive strengths in order to absorb acoustic energy. Unfortunately, these soft acoustic isolators do not support live loads applied to the CLT floors and deflect as a result. Rubber based isolators, which use recycled or various virgin rubber compounds, have also been used to support an upper flooring of CLT flooring systems. However, these rubber based isolators deflect in excess of the amount allowed by the International Building Code and are expensive.
Another drawback of conventional rubber acoustic isolators is that certain building codes do not allow combustible materials in concealed spaces within the flooring/ceiling assembly. The space between a subfloor and an upper flooring of a flooring system can be interpreted as a “concealed space,” meaning the acoustic isolators in those flooring systems, including CLT flooring systems, cannot be made of rubber, which is combustible.
Accordingly, there is the need for an acoustic isolator which addresses the above-listed drawbacks.
The above-listed need is met or exceeded by the present acoustic isolators. For elevated flooring systems, including CLT flooring systems, where improved and code mandated IIC and STC performance is desired, gypsum, Portland or magnesium oxide based cement isolators provide low deflection and high load bearing capacities. Specifically, the present acoustic isolator includes a cement-based acoustic isolator which is made of gypsum, Portland cement or magnesium oxide that is optionally cast into a specific shape, or sheets of the materials layered to support raised acoustic floors. In the present application, “cement-based”, refers to a panel or isolator made of gypsum, Portland cement, or magnesium oxide. These layers or sheets are preferably attached to one another with an adhesive. The deflection and the acoustic performance of the present cement-based acoustic isolators satisfy building code requirements and are made at a fraction the price of the rubber isolators. The cement-based acoustic isolators are reinforced with strong compressive strength materials, which provide acoustic performance, and also support heavy code mandated live loads.
The present acoustic isolators also include a reinforced acoustic isolator which includes insulation layers, preferably made of high-density fiberglass board, that provide sound dampening. Additionally, the reinforced acoustic isolator preferably is embedded with reinforcing supports such that when subject to normal everyday loading, the reinforced acoustic material of the isolator is able to support live loads. In an embodiment, the reinforced acoustic isolators include a stack of thin nonwoven reinforced fiber insulation layers which are cored or drilled into to form a hole. The hole within the stack of thin nonwoven reinforced fiber insulation layers is preferably filled with a slurry of gypsum, Portland cement or magnesium oxide. In particular, the gypsum slurry, which has increased foam once set, provides load-bearing, enhanced acoustic properties and disruption of sound transmission.
A combination of the high-density fiberglass board insulation layers and the gypsum, Portland cement or magnesium oxide provide improved acoustic performance and resistance to compressive forces. When large live loads are applied to the insulation layers, the material of the insulation layers is depressed and deflects downwards to the point where the floor panels, such as the CLT subfloor, come into contact with the reinforcing material embedded in the isolators which stops the downward deflection. The amount of downward deflection is calculated and built into the acoustic isolator, such that the deflection is within the requirements of the building code dictated deflection limits.
When the live load is removed, the isolators return to their normal height. This allows the reinforced acoustic isolators to comply with code requirements for sound reduction and floor deflection.
More specifically, a cement-based acoustic isolator for use in a composite flooring system which includes a Cross Laminated Timber (CLT) subfloor, a metal inverted track attached to a top surface of the cement-based acoustic isolator, and an upper flooring attached to a top surface of the metal inverted track, includes a plurality of structural panel layers stacked upon one another; and an adhesive which secures the plurality of structural panel layers to one another. The adhesive also secures the plurality of structural panel layers to the metal inverted track and the CLT subfloor of the composite flooring system.
In preferred embodiments, the cement-based acoustic isolator is at least 4 inches tall, the plurality of structural panel layers include a top paper sheet and a bottom paper sheet, and the cement-based acoustic isolator is in the shape of a cube or a rectangular prism.
Additionally, a composite flooring system includes a Cross Laminated Timber (CLT) subfloor, and a plurality of cement-based acoustic isolators disposed on top of and attached to the CLT subfloor. The cement-based acoustic isolators include a plurality of structural panel layers stacked upon one another; and an adhesive which secures the plurality of structural panel layers to one another. The composite flooring system also includes a plurality of metal inverted tracks attached to a top surface of the plurality of acoustic isolators; and an upper flooring attached to a top surface of the metal inverted tracks.
In preferred embodiments, the cement-based acoustic isolators are at least 4 inches tall, the plurality of structural panel layers comprise a top paper sheet and a bottom paper sheet, and the cement-based acoustic isolators are in the shape of a cube or a rectangular prism. Preferably, the CLT subfloor includes five layers of CLT panels, such that successive layers are stacked in a perpendicular orientation, and the upper flooring includes two layers of structural panels stacked in a perpendicular orientation or in a parallel orientation with staggered joints between the layers of structural panels.
In yet another preferred embodiment, the two layers of structural panels are attached with an adhesive or a combination of the adhesive and fasteners. In an alternate preferred embodiment, the upper flooring includes a layer of structural panels with a poured underlayment above the layer of structural panels. Preferably, the upper flooring includes a sound mat disposed between the layer of structural panels and the poured underlayment.
Preferably, the cement-based acoustic isolators are spaced 24 inches apart, and a space between the CLT subfloor and the top gypsum layer is filled with insulation.
Moreover, a reinforced cement-based acoustic isolator used in a flooring system includes a stack with a plurality of insulation layers secured to one another with an adhesive. The stack includes a hole, such that a cement product fills the hole. In preferred embodiments, the plurality of insulation layers includes high-density non-woven fiberglass boards, the cement product includes gypsum poured to fill the hole, and the hole is drilled into the stack of insulation layers secured to one another with the adhesive.
Referring now to
Conventionally, subfloors have been made with materials such as poured concrete or at least one layer of plywood as is known in the art. However, more recently, CLT has emerged as a popular material for use in subfloors. Specifically, CLT provides desirable mechanical properties, while being more cost effective than other conventional subfloor materials. As is known in the art, the subfloor 12 is optionally self-supporting between beams or is supported by joists (not shown) typically made of wood, steel, or concrete.
Additionally, a plurality of metal inverted “U”-tracks 16, each having a top surface 18, are attached to the plurality of acoustic isolators 14. An upper flooring 20 is secured to the top surface 18 of the inverted metal tracks 16.
The subfloor 12 has a plurality of layers 22 which preferably include CLT panels 24. In a preferred embodiment, each of the layers 22 is arranged such that the CLT panels 24 are oriented perpendicularly with respect to the CLT panels located on the layer immediately above or below. Preferably, the subfloor 12 includes between three and seven layers 22 of CLT panels 24, with five layers being the most preferred.
Additionally, a top layer 26 of the subfloor 12 includes an upper surface 28 upon which the plurality of acoustic isolators 14 are disposed. The upper flooring 20 includes at least one structural panel layer 30 which is preferably made of a plurality of structural panels 32. A “structural” panel, as used herein, is capable of supporting its own weight without visible sagging, bending, or collapsing when supported only at the edges of the panel as in a floor and ceiling assembly.
In an embodiment, the structural panels 32 are not conventional gypsum wallboard, but are of the fiber-reinforced cement board type sold by United States Gypsum Co. (USG) as Structural Panel Concrete Subfloor, also sold under the trademark STRUCTO-CRETE® panels. Alternatively, the structural panels 32 are made of conventional gypsum wallboard panels. Preferably, the structural panels 32 are at least 0.5 inch tall.
Various types of panels are optionally used as the structural panels 32. The structural panels 32 are optionally fiber reinforced Portland cement panels, magnesium oxide cement panels, wood panels such as plywood or OSB covered with a noncombustible gypsum topping, cast Portland cement or Portland cement panels, gypsum cement concrete tiles, or other structural panels as are known in the art. Specifically, gypsum slurry with increased foam, and larger bubbles, provides enhanced acoustic properties and superior disruption of sound transmission.
For example, U.S. Pat. No. 8,038,790 to Dubey et al., incorporated herein by reference, discloses cement panels able to resist lateral forces imposed by high wind and earthquake. The principal starting materials used to make the cement panels are inorganic binder, e.g., calcium sulfate alpha hemihydrate, hydraulic cement, and pozzolanic materials, lightweight filler coated expanded perlite and optional additional, ceramic microspheres or glass microspheres, as well as superplasticizer, e.g., polynapthalene sulphonates and/or polyacrylates, water, and optional additives.
Further, U.S. Pat. No. 6,620,487 to Tonyan et al., incorporated herein by reference, discloses a reinforced, lightweight, dimensionally stable panel capable of resisting shear, uniform, and concentrated loads when fastened to framing equal to or exceeding shear, uniform, and concentrated loads provided by plywood or oriented strand board panels. It is contemplated that the structural panels 32 optionally include cement panels made according to each of the preceding patents incorporated by reference.
Various methods are optionally employed to make the structural panels 32. For example, U.S. Pat. No. 7,670,520 to Dubey et al., incorporated by reference, discloses a process for producing fiber-reinforced structural cementitious panels made of at least one layer of fiber reinforced cementitious slurry, the process for each such layer of slurry including providing a moving web; depositing a first layer of individual, loose fibers upon the web; depositing a layer of settable slurry upon the deposited first layer of individual, loose fibers; depositing a second layer of individual, loose fibers upon the deposited layer of settable slurry; and actively embedding both layers of individual, loose fibers into the layer of slurry to distribute the fibers throughout the slurry.
Referring to
The bottom structural panels 32a are attached to the upper surface 18 of the inverted metal tracks 16 by either fasteners, an adhesive 34 or a combination of fasteners and the adhesive. In an embodiment, the bottom structural panels 32a are attached to the inverted metal tracks 16 with fasteners such as screws, nails, or other fasteners as are known in the art. Alternatively, a combination of the adhesive 34 and fasteners are used to attach the bottom structural panels 32a to the inverted metal tracks 16, such that the fasteners are either removed once the adhesive sets or remain after the adhesive has set.
Similarly, the adhesive 34 is preferably used to attach the bottom structural panel layer 30a to the top structural panel layer 30b. In a preferred embodiment, a combination of the adhesive 34 and fasteners are used to attach the top structural panels 32b to the bottom structural panels 32a, such that the fasteners secure the top structural panels to the bottom structural panels and the inverted metal track 16 and are either removed once the adhesive sets or remain after the adhesive has set. Optionally, the top structural panels 32b are secured only to the bottom structural panels 32a and are optionally secured only by fasteners. A preferred, but non-limiting adhesive is LiquidNails® adhesive.
Preferably, the space around the acoustic isolators 14 includes insulation 36 which may be foam, fiberglass or the like, as is known in the art.
Referring to
A preferred sound mat 42 is Levelrock® SAM-N25 Sound Attenuation Mat sold by USG, and a preferred underlayment is one inch Levelrock® 2500 Floor Underlayment sold by USG.
Referring now to
While the cement-based acoustic isolator 50 depicted in
Preferably, the cement-based acoustic isolator 50 is formed as a cube that is at least two inches tall, and preferably still at least four inches tall, as is known in the art. In a preferred embodiment of the CLT flooring system 10, the cement-based acoustic isolators 50 are each spaced twenty-four inches away from the nearest cement-based acoustic isolator, and the cement-based acoustic isolators are evenly spaced upon the top layer 26.
In an embodiment, the cement-based acoustic isolators 50 are made with structural panels 32 that include cement imbedded with fibers, such as ⅝ inch USG Sheetrock® Brand Firecode® X Panels. Alternatively, the cement-based acoustic isolator 50 is optionally made of gypsum wallboard panels. A cement-based acoustic isolator 50 made with gypsum wallboard panels was tested to measure compressive strength and sound dampening properties. The test demonstrated that the cement-based acoustic isolator 50 provides superior resistance to deflection than current rubber based acoustic isolators, while still providing sufficient acoustic dampening to satisfy building requirements.
Referring now to
U.S. Pat. No. 9,828,287 to Swift et al., incorporated herein by reference, discloses an insulation board which is a thermal and acoustical insulation product that includes glass fibers that are preformed into boards and bonded with a thermoset binder. Swift also discloses applying a binder to glass fibers as they are being produced, forming the binder and fiberglass into a mat, volatizing water from the binder, and heating the high-solids binder-coated fibrous glass mat to cure the binder to thereby produce a finished fibrous glass bat which may be used, for example, as a thermal or acoustical insulation product, a reinforcement for a subsequently produced composite, etc.
Further, U.S. Pat. No. 9,039,827 to Hampson, incorporated herein by reference, discloses a finished mineral fiber thermal insulation material which includes a collection of non-woven mineral fibers maintained together by a cured, substantially water insoluble, substantially formaldehyde-free, nitrogenous polymer-containing binder. It is contemplated that the insulation layers 52 is optionally made according to each of the preceding patents incorporated by reference.
While
The insulation layer stack 64 is preferably drilled with a vertical counterbore to form a hole 66 in the bottom of the insulation layer stack. It is preferred that the hole 66 does not pass entirely through the insulation layer stack 64. The hole 66 is filled with a cement product 68 which preferably includes one of gypsum, Portland cement, or magnesium oxide. It is contemplated that the cement product 68 is poured into the hole 66 directly or is poured into a mold with a shape matching the hole 66 and inserted into the hole in the insulation layer stack 64. Alternatively, a stack of structural panels 32, which are attached to one another with the adhesive 34, are optionally used as the cement product 68, as is known in the art.
The reinforced acoustic isolators 60 provided improved resistance to compression compared to typical acoustic isolators. Specifically, the cement product 68 provides structural support to the reinforced cement-based acoustic isolators 60. When large live loads are applied to the reinforced acoustic isolators 60, the insulation layers 62 are only able to deflect to the point of the cement product 68. The amount of downward deflection of the reinforced acoustic isolators 60 is calculated and built into the reinforced acoustic isolator, such that the deflection is within the requirements of the building code dictated deflection limits. When the loading is removed from the upper flooring 20, the insulation layers 62 above the cement product 68 return to their normal height.
While a particular embodiment of the present acoustic isolators 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.
The present application is a Non-Provisional of, and claims 35 USC 119 priority from, U.S. Provisional Application Ser. No. 63/609,588 filed on Dec. 13, 2023, the entire contents of which are incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 63609588 | Dec 2023 | US |
