Patent Application
20190218795
The invention relates to solid wood or mass timber-based floor panel assemblies that provide acoustic separation.
Prior art floor assemblies, such as traditional stick-framed floor assemblies, include high density vertical elements, such as wood-product based floor joists (e.g., engineered wood joists) that couple to a top layer of the floor, such as plywood subflooring, and to a bottom layer of the floor, such as ceiling material, e.g., gypsum, for a lower level of a building. The vertical elements facilitate transfer of air-borne acoustic vibration and transfer of an impact- or structure-borne acoustic vibration between the top layer and the bottom layer. What is needed is a floor assembly that lessens the transfer of air-borne acoustic vibration and transfer of an impact- or structure-borne acoustic vibration between the top layer and the bottom layer, for example, by not using any high density vertical elements.
Embodiments are illustrated by way of example, and not by way of limitation, and can be more fully understood with reference to the following detailed description when considered in connection with the figures in which:
With reference to
In one embodiment, a building assembly using a mass timber structural panel layer 105 of 162 mm in thickness attains a sound transmission class (STC) rating of at least 50 for airborne sound separation, attains a field sound transmission class (FSTC) rating of 45 for airborne sound separation, attains an impact insulation class (IIC) rating of at least 50 for impact sound separation, and attains a field impact insulation class (FIIC) rating of at least 45 for impact sound separation.
In another embodiment, the building assembly using a mass timber structural panel layer 105 of 140 mm in thickness attains a Field Sound Transmission Class rating in the range of 50-52. In this embodiment, the building assembly attains an Apparent Impact Insulation Class rating in the range of 47-50.
In one embodiment, the solid wood or mass timber structural panel layer 105 in the building assemblies 100A, 100B includes a number of solid wood panel products fastened to each other to create a solid flat plate structural floor having a thickness in the range of 140-173 mm and a weight in the range of 14.2 to 16.4 pounds/square foot. In one embodiment, the solid wood panel products fastened to each other is cross laminated timber (CLT) product having a number of layers (5 layers depicted at 105 in
In the embodiments, the solid wood or mass timber structural panel layer 105 is capable of supporting, from a strength and serviceability standpoint, a uniform building load of at least 100 pounds/square foot, and a concentrated building load of at least 2,000 pounds applied to a localized area of 2.5 ft×2.5 ft. (These are requirements found in Section 1607 of the International Building Code (IBC) and encompass assembly, office, and residential loading requirements.)
In one embodiment, the solid wood or mass timber structural panel layer 105 attains an Apparent Impact Insulation Class rating in the range of 18-20 and attains a Field Sound Transmission Class rating in the range of 36-37.
The embodiment 100A of the building assembly uses a lightweight panel layer 110 made of a wood product-based panel layer, such as: a medium density fiberboard (MDF) panel having a thickness of approximately ¾″ and a weight in the range of 3.1 to 4.25 pounds/square foot, or a tongue and groove plywood panel having a thickness of approximately ¾″ and a weight of approximately 2.1 pounds/square foot. In the embodiment 100A, the building assembly further includes a tongue and groove plywood panel having a thickness of approximately ¾″ and a weight of approximately 2.1 pounds/square foot fastened to (e.g., screwed to) the wood product-based panel layer.
The embodiment 100B of the building assembly uses a lightweight panel layer 110 made of a particleboard panel having a thickness of approximately 1″ and a weight of approximately 4.25 pounds/square foot. In the embodiment 100B, the building assembly further includes a plywood panel having a thickness of approximately ½″ and a weight of approximately 1.5 pounds/square foot fastened to the particleboard panel. Alternatively, the embodiment 100B of the building assembly uses a lightweight panel layer 110 made of a number of layers of structural board. In the embodiment, each structural board is made of cellulose fiber having a thickness of approximately ⅝″ (e.g., ⅝″ Homasote 440 SoundBarrier™ panels) and a weight of approximately 1.5 pounds/square foot.
The embodiment 100B of the building assembly further includes another layer 125 of the structural board, or a plywood panel having a thickness of approximately ½″ and a weight of approximately 1.5 pounds/square foot, fastened to the layers of structural board.
One embodiment of the invention contemplates the building assembly using a lightweight panel layer 110 made of a cement product-based panel layer, such as cement board. In one embodiment, multiple layers of cement board may be used, each having a thickness varying between ¼″ to 1″.
In the building assembly of the embodiments of the invention, the acoustically absorptive solid volume material layer 115 is sandwiched between the solid wood or mass timber structural panel layer 105 and the lightweight panel layer 110. In one embodiment, the layer is made of one or more compressed mineral wool insulation boards. In one embodiment, there are 3 boards each 1″ in thickness, wherein the overall thickness of the layer 115 is approximately 3″ and weighs approximately 3⅛ pounds/square foot. In one embodiment, the layer consists of a high-density, stone wool insulation board, e.g., Roxul® Monoboard®, or a high-density uncoated stone wool insulation board, e.g., Roxul® TopRock® DD, or an equivalent product. Importantly, the acoustically absorptive solid volume material layer 115 transfers a uniform structural load and/or a concentrated structural load applied to the lightweight panel layer 110 from the lightweight panel layer 110 to the solid wood or mass timber structural panel layer 105.
The building assembly according to embodiment 100A may further include a plywood subfloor 125 adjacent an outside surface of the lightweight panel layer 110. It is contemplated that a floor topping treatment is applied to the building assembly of the variously described embodiments. This floor topping treatment may be a finished floor material 130 adjacent an outside surface of the plywood subfloor 125. Such finished floor material might be carpeting, a carpet pad, tile, vinyl, or ceramic tile.
Advantageously, the building assembly in the described embodiments may be manufactured off-site as a number of standard sized modular panels of 4′×8′, or larger dimensions, which are then shipped to a building site for installation and use in the floor and/or ceiling of the building.
Embodiments of the invention contemplate a floor topping (e.g., carpet, carpet pad, tile, vinyl, etc.) treatment. Such floor topping treatments are not integral to the acoustic rated assembly in the described embodiments, that is, the embodiments described herein meet the code minimum requirements without applying the floor topping treatments. However, applying a finish floor product to the embodiments of the invention will further improve the impact acoustic performance of the described embodiments.
One embodiment of the invention also incorporates design elements such as exposing the underside of the solid wood or mass timber structural panel layer for architectural and aesthetic reasons, and avoiding the use of a wet trade cement-based product(s), such as gyperete, to improve constructability and efficiency.
Embodiments of the invention were tested for both airborne and impact sound isolation utilizing the methods outlined in ASTM E336: Standard Method for Measurement of Airborne Sound Insulation in Buildings and ASTM E1007: Standard Test Method for Field Measurement of Tapping Machine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support Structures to characterize the airborne and impact noise isolation performance of the embodiments.
Embodiments of the invention meet the International Building Code (IBC) section 1207.2 requirements for field sound transmission class (FSTC) and IBC section 1207.3 requirements for field impact isolation class (FIIC). Per IBC section 1207.1, these requirements apply to common interior walls, partitions and floor/ceiling assemblies between adjacent dwelling units and sleeping units or between dwelling units and sleeping units and adjacent public areas such as halls, corridors, stairways or service areas. Section 1207.2 requires that walls, partitions and floor/ceiling assemblies separating dwelling units and sleeping units from each other or from public or service areas shall have a sound transmission class of not less than 50 if laboratory tested, or not less than 45 if field tested, for air-borne noise when tested in accordance with ASTM E 90. Penetrations or openings in construction assemblies for piping; electrical devices; recessed cabinets; bathtubs, soffits; or heating, ventilating or exhaust ducts shall be sealed, lined, insulated or otherwise treated to maintain the required ratings. Section 1207.3 requires that floor/ceiling assemblies between dwelling units and sleeping units or between a dwelling unit or sleeping unit and a public or service area within the structure shall have an impact insulation class rating of not less than 50 if laboratory tested, or not less than 45 if field tested, when tested in accordance with ASTM E 492.
Although embodiments of the invention have been described and illustrated in the foregoing illustrative embodiments, it is understood that present disclosure has been made only by way of example, and that numerous changes in the details of implementation of the invention can be made without departing from the spirit and scope of embodiments of the invention, which is only limited by the claims that follow. Features of the disclosed embodiments can be combined and rearranged in various ways.
