Patent Publication Number: US-11649644-B2

Title: Field-assembled water control flooring systems

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/783,158 filed Feb. 5, 2020 and entitled “FIELD-ASSEMBLED WATER CONTROL FLOORING SYSTEMS,” which is a continuation-in-part of U.S. patent application Ser. No. 16/531,106 filed Aug. 4, 2019 and entitled “FIELD-ASSEMBLED FLOORING SYSTEMS WITH ISOLATION BOARDS” (now U.S. Pat. No. 10,655,343 issued May 19, 2020), which is a continuation-in-part of U.S. patent application Ser. No. 16/269,556 filed Feb. 6, 2019 and entitled “FIELD-ASSEMBLED FLOORING SYSTEMS” (now U.S. Pat. No. 10,662,657 issued May 26, 2020), which claims priority to U.S. Provisional Application No. 62/627,154 filed Feb. 6, 2018 and entitled “FIELD-ASSEMBLED FIRE RATED FLOORING SYSTEMS,” each of which is expressly incorporated by reference herein in its entirety for all purposes. 
    
    
     BACKGROUND 
     Field 
     The present disclosure generally relates to flooring systems and, in particular, to field-assembled floor underlayments. 
     Description of Related Art 
     Flooring systems come in a wide variety of different configurations depending upon the type of building in which they are employed and their intended use. Flooring systems generally include a finish flooring and a subfloor and can include an intermediate layer called an underlayment. Finish flooring is generally the uppermost layer of the flooring system. Known finish flooring materials include wood flooring and resilient flooring. Resilient flooring comprises linoleum, asphalt tiles, vinyl or rubber tiles and the like. The subfloor is typically the structure of the building which supports the remainder of the floor system. Some subfloor materials include wood, such as plywood, or reinforced concrete. Flooring systems, especially those including reinforced-concrete subfloors, may additionally include a vapor barrier and/or acoustic- or fire-rated materials in the underlayment. 
     SUMMARY 
     According to a number of implementations, the present disclosure relates to a method for installing a hybrid underlayment having a combination of structural boards and a cementitious product. The method includes applying adhesive to adhere an isolation board to a subfloor in a targeted area, the targeted area lying within a first portion of the subfloor. The method also includes installing the isolation board to the subfloor with the adhesive in the targeted area so that there is a gap between adjacent isolation boards and walls. The method also includes applying adhesive to adhere a bottom side of a structural board to a top side of the installed isolation board. The method also includes installing the structural board on top of the installed isolation board. The method also includes pouring cementitious product in a second portion of the subfloor so that the poured cementitious product is level with a top side of the structural board. A combination of the isolation board and structural board provide a pour stop for the cementitious product. 
     In some embodiments, the method further includes fastening the isolation board in place with nails. In some embodiments, the method further includes fastening the structural board in place with nails. 
     In some embodiments, the first portion and the second portion cover the entire subfloor. In some embodiments, the isolation board comprises a fire-rated cellulose fiberboard. In some embodiments, the structural board comprises a fire-rated cellulose fiberboard. In some embodiments, a thickness of a combination of the installed isolation board and the installed structural board is greater than or equal to 1 inch and less than or equal to 2 inches. In some embodiments, the cementitious product comprises gypsum concrete. In some embodiments, a width of the isolation board is less than or equal to 96 inches. In some embodiments, a width of the isolation board is less than or equal to 6 inches and greater than or equal to 4 inches. 
     According to a number of implementations, the present disclosure relates to a flooring system having a hybrid underlayment. The flooring system includes an isolation board adhered to a first portion of a subfloor. The flooring system also includes a structural board adhered to the isolation board, the structural board having a thickness so that a combined thickness of the isolation board and the structural board is a targeted thickness. The flooring system also includes a cementitious product poured on a second portion of the subfloor, the cementitious product poured to have a thickness that is equal to the targeted thickness. A combination of the isolation board and the structural board serves as a pour stop for the cementitious product. 
     In some embodiments, the first portion of the subfloor does not extend beyond a footprint of a bathtub in a finished building. In some embodiments, the first portion of the subfloor is situated in a dead space of a finished building. In some embodiments, the first portion of the subfloor is restricted to a floor of a closet of a finished building. In some embodiments, the first portion of the subfloor does not extend more than 12 inches from a wall of a finished building. In some embodiments, the first portion of the subfloor does not extend beyond a footprint of a kitchen island in a finished building. In some embodiments, the combined thickness is greater than or equal to 1 inch and less than or equal to 2 inches. In some embodiments, the cementitious product comprises gypsum concrete. In some embodiments, the isolation board comprises fire-rated cellulose fiberboard. In some embodiments, the structural board comprises fire-rated cellulose fiberboard. 
     According to a number of implementations, the present disclosure relates to a method for installing a flooring system. The method includes securing wall isolation boards to studs of a wall frame so that a bottom edge of the wall isolation board is adjacent to a subfloor and a top edge of the wall isolation board is less than or equal to about 12 inches above the subfloor, the wall isolation boards being installed adjacent to one another to cover a portion of the wall frame. The method also includes installing a sound control membrane over a portion of the subfloor. The method also includes installing an isolation strip to a face of the wall isolation boards with a bottom edge of the isolation strip adjacent to the sound control membrane. The method also includes pouring cementitious product over the sound control membrane so that the poured cementitious product reaches a targeted height that does not exceed a top edge of the isolation strip. 
     In some embodiments, securing the wall isolation boards to the wall frame includes using at least two dry wall screws for each wall isolation board. In some embodiments, the method further includes applying a tape material at a transition between the sound control membrane and the isolation strip. In some embodiments, the sound control membrane extends over the entire subfloor between wall frames of a building. In some embodiments, the wall isolation boards comprise fire-rated cellulose fiberboard. In some embodiments, a thickness of the wall isolation boards is greater than or equal to about 0.5 inches and less than or equal to about 1 inch. In some embodiments, the cementitious product comprises gypsum concrete. In some embodiments, the targeted height is less than or equal to about 1.5 inches. In some embodiments, an edge of the sound control membrane is adjacent to the wall isolation boards. 
     According to a number of implementations, the present disclosure relates to a method for installing a flooring system. The method includes securing wall isolation boards to studs of a wall frame so that a bottom edge of the wall isolation board is adjacent to a subfloor and a top edge of the wall isolation board is less than or equal to about 12 inches above the subfloor, the wall isolation boards being installed adjacent to one another to cover a portion of the wall frame. The method also includes securing floor isolation boards to a first area of the subfloor, wherein the floor isolation boards are adjacent to the wall isolation boards. The method also includes installing a sound control membrane over a portion of a second area of the subfloor. The method also includes pouring cementitious product over the second area of the subfloor so that the poured cementitious product reaches a targeted height that does not exceed a top edge of the floor isolation boards. 
     In some embodiments, securing the wall isolation boards to the wall frame includes using at least two dry wall screws for each wall isolation board. In some embodiments, securing the floor isolation boards to the subfloor includes using a combination of adhesives and mechanical fasteners. In some embodiments, the method further includes applying a tape material at a transition between the sound control membrane and the floor isolation boards. In some embodiments, the sound control membrane extends over the entire second area of the subfloor. In some embodiments, the wall isolation boards comprise fire-rated cellulose fiberboard. In some embodiments, the floor isolation boards comprise fire-rated cellulose fiberboard. In some embodiments, a thickness of the wall isolation boards is greater than or equal to about 0.5 inches and less than or equal to about 1 inch. In some embodiments, a thickness of the floor isolation boards is greater than or equal to about 1 inch and less than or equal to about 2 inches. In some embodiments, the cementitious product comprises gypsum concrete. In some embodiments, the method further includes installing drywall above the wall isolation boards. 
     According to a number of implementations, the present disclosure relates to a method for installing a flooring system. The method includes securing a wall isolation board to a wall frame so that a bottom edge of the wall isolation board is adjacent to a subfloor and a top edge of the wall isolation board is less than or equal to about 12 inches above the subfloor. The method also includes installing a waterproof layer that extends from the subfloor and up the wall isolation boards to cover a seam between the subfloor and the wall isolation board. The method also includes pouring cementitious product over the subfloor so that the poured cementitious product reaches a targeted height that does not exceed a top edge of the waterproof layer. 
     According to a number of implementations, the present disclosure relates to a method for installing a flooring system. The method includes securing a wall isolation board to a wall frame so that a bottom edge of the wall isolation board is adjacent to a subfloor and a top edge of the wall isolation board is less than or equal to about 12 inches above the subfloor. The method also includes securing a floor isolation board to the subfloor so that it abuts with a portion of the wall isolation board and extends less than or equal to about 12 inches onto the subfloor. The method also includes installing a waterproof layer that extends from the subfloor, over the floor isolation board, and up the wall isolation board to cover a seam between the subfloor and the floor isolation board and to cover a seam between the floor isolation board and the wall isolation board. The method also includes pouring cementitious product over the subfloor so that the poured cementitious product reaches a targeted height that does not exceed a top edge of the waterproof layer. 
     For purposes of summarizing the disclosure, certain aspects, advantages and novel features have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, the disclosed embodiments may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments are depicted in the accompanying drawings for illustrative purposes and should in no way be interpreted as limiting the scope of the inventions. In addition, various features of different disclosed embodiments can be combined to form additional embodiments, which are part of this disclosure. Throughout the drawings, reference numbers may be reused to indicate correspondence between reference elements. The drawings are not necessarily to scale so unless otherwise indicated no relative or absolute dimensions should be inferred from the following figures. 
         FIGS.  1 A,  1 B,  1 C,  1 D,  1 E,  1 F, and  1 G  illustrate installation of an underlayment layer of flooring using fiber boards for an inside corner binder. 
         FIGS.  1 H and  1 I  illustrate cross-sections of the flooring of  FIGS.  1 A- 1 G  after installation of a cementitious product. 
         FIGS.  2 A,  2 B,  2 C,  2 D,  2 E, and  2 F  illustrate another example installation of an underlayment layer of flooring using fiber boards for a perimeter board binder. 
         FIGS.  3 A and  3 B  illustrate another example installation of an underlayment layer under a bathroom tub. 
         FIGS.  4 A and  4 B  illustrate another example installation of an underlayment layer under a closet. 
         FIGS.  5 A and  5 B  illustrate another example installation of an underlayment layer for an outside corner binder. 
         FIGS.  6 A and  6 B  illustrate installation of an underlayment layer for an inside corner binder. 
         FIGS.  7 A and  7 B  illustrate installation of an underlayment layer for an island in a kitchen. 
         FIGS.  8 A and  8 B  illustrate installation of an underlayment layer of flooring in a dwelling. 
         FIGS.  9 A,  9 B,  9 C,  9 D,  9 E, and  9 F  illustrate another example installation of an underlayment layer of flooring using fiber boards for an outside corner binder. 
         FIGS.  10 A,  10 B,  10 C,  10 D,  10 E,  10 F, and  10 G  illustrate another example installation of an underlayment layer of flooring using fiber boards as a bathtub binder. 
         FIGS.  11 A,  11 B,  11 C,  11 D, and  11 E  illustrate another example installation of an underlayment layer of flooring using fiber boards as a bedroom closet binder. 
         FIGS.  12 A,  12 B,  12 C,  12 D,  12 E, and  12 F  illustrate another example installation of an underlayment layer of flooring using fiber boards as a kitchen island binder. 
         FIGS.  13 A,  13 B,  13 C,  13 D, and  13 E  illustrate a plan view of an installation of an underlayment layer of flooring in a dwelling. 
         FIG.  14    illustrates a flow chart of an example method for installing a hybrid underlayment of structural boards and a cementitious product. 
         FIG.  15    illustrates a cross-section of flooring having floor isolation boards and a cementitious product. 
         FIG.  16    illustrates a cross-section of flooring having floor isolation boards, wall isolation boards, and a cementitious product. 
         FIG.  17    illustrates a cross-section of flooring having wall isolation boards and a cementitious product. 
         FIG.  18    illustrates a cross-section of flooring having floor isolation boards, wall isolation boards, and a cementitious product forming an underlayment layer, and includes a waterproof coating to provide water-control features to the flooring. 
         FIG.  19    illustrates a cross-section of flooring having wall isolation boards and a cementitious product forming an underlayment layer, and includes a waterproof coating to provide water-control features to the flooring. 
         FIG.  20    illustrates a cross-section of flooring to illustrate that any of the flooring embodiments described herein can be installed over drywall attached to a wall frame. 
         FIG.  21    illustrates a flow chart of an example method for installing floor isolation boards and a cementitious product. 
         FIG.  22    illustrates a flow chart of an example method for installing floor and wall isolation boards and a cementitious product. 
         FIG.  23    illustrates a flow chart of an example method for installing wall isolation boards and a cementitious product. 
         FIG.  24    illustrates a flow chart of an example method for installing isolation boards and a waterproof layer. 
     
    
    
     DETAILED DESCRIPTION OF SOME EMBODIMENTS 
     The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the claimed invention. 
     Overview 
     Flooring in buildings such as dwellings typically include a subfloor, an underlayment, and a finish floor or floor covering. The topmost layer is the finish floor which is the visible and exposed part of the floor. This layer is not required to provide structural support, but often provides a type of supplementary support. The bottom-most layer is the subfloor. The subfloor is the thick flat surface on which all other layers rest. The subfloor may rest on joists, the foundation, or other structure, or in the case of a concrete slab, the slab may be considered the subfloor. 
     Underlayment is a layer that sits between the subfloor and the finish floor. The underlayment can facilitate the laying of floor coverings, for example, carpet, tile, wood parquet, and vinyl, and may result in a more stable finished floor. The underlayment may also have sound reduction and/or other desirable properties such as water control or waterproofing. Sound reduction is particularly significant where the maximum allowable level of sound transmission is controlled by local building codes, which is increasingly common. For example, underlayment can be used to reduce the transmission of sound through the floor to a room below in a multi-floor building. Water control is particularly desirable to protect the floor, foundation, subfloor, structure, etc. from water damage. In addition, water control may include containing water within a particular area so that water damage does not spread to other rooms, units, and/or floors in a building. Underlayment may typically be a cementitious product, such as gypsum concrete, cellulose fiberboards, and/or gypsum-based boards. Many pourable floor topping mixtures, which are suitable for incorporation in underlayment systems, are gypsum-based, in order to provide a level of fire protection by retarding the spread of flames. An example of gypsum-based floor topping mixtures is GYP-CRETE®, which is available from MAXXON® Corporation. Gypsum-based pourable floor toppings are generally installed in dwellings, which are under construction and subject to building codes that require minimum fire ratings. 
     Cementitious underlayment products have some sound reduction properties; however, the use of cementitious underlayment products and other similar products pose significant challenges for builders. One significant issue is that such products are applied as a wet product (e.g., poured as a thick fluid onto a subfloor) into an otherwise dry environment (e.g., a wood framed building). When such a wet product is applied to a dry environment, the moisture can adversely affect the building process. Issues such as warping of wooden elements, splashing onto unintended surfaces, etc. are common. Furthermore, introducing moisture into any environment increases the chances of mold growth in the environment, which is always an unwanted condition. Another issue is that the application of any wet product typically requires a drying, curing, or setting period following the pouring or application of the wet product. Such periods can cause delays in construction and complicate the planning and project management between various contractors and workers. 
     Pourable floor toppings are typically installed in two stages: first, over the portions of a dwelling subfloor where fixtures such as bath tubs are to be installed (these portions being designated as pre-pour areas); and, then, over the remainder of the subfloor, following the installation of the fixtures. Although the pre-pour areas are relatively small compared to the remainder of the subfloor, installation of the pourable floor topping to the pre-pour areas requires dispatching to the construction site all of the necessary equipment and crew that, subsequently, must be dispatched again, after installing the bathtubs and other such fixtures, to install the remainder of the floor topping to complete the underlayment system. 
     Underlayments that use structural boards, such as fiberboards, in place of cementitious products also present difficulties. For example, structural boards typically do not pass acoustical rating requirements for buildings in certain geographical locations. In addition, it may be more difficult to install finish flooring on top of fiberboards. Similarly, typical structural boards do not provide water-resistant and/or water-containing features that may be particularly desirable for buildings such as dwellings and multifamily housing structures. 
     Accordingly, to address these and other challenges and to satisfy demands in the marketplace, described herein are methods for installing field-assembled flooring systems wherein the underlayment is a hybrid design that includes a combination of structural board and cementitious product. The hybrid design is configured to reduce or eliminate the curing time requirement after pouring the cementitious product (e.g., gypsum concrete). In some embodiments, the field-assembled flooring systems can reduce or eliminate the chances of the onset of mold due to high moisture levels by removing the cementitious product from the prone areas (e.g., near inner or outer walls) and replacing it with structural boards. Similarly, the disclosed installation methods may reduce construction time and cost by enabling a single pour for the cementitious product rather than two pouring stages, as is the case in some construction projects. The structural boards (e.g., fiberboards and/or gypsum boards) can be installed in non-critical areas such as, for example and without limitation, underneath cabinets, around the perimeter of the floor, under bathtubs, in non-walk-in closets, anywhere drywall reaches the floor, or the like. 
     Moreover, described herein are methods for installing flooring systems that have isolation boards or panels secured to a wall to improve isolation. The flooring systems can include isolation panels on the walls and can be installed with or without isolation boards being used as part of the underlayment. For example, isolation panels can be installed on a wall using fasteners and a cementitious product can be poured to form the underlayment wherein the cementitious product contacts the isolation panels installed on the wall. As another example, wall isolation panels can be installed on a wall using fasteners and floor isolation panels can be installed on portions of the subfloor and a cementitious product can be poured to form the underlayment in combination with the floor isolation boards. In these embodiments, a sound control membrane can also be installed on the subfloor or as part of the underlayment. Tape may also be used in conjunction with the isolation boards and the sound control membrane during installation. 
     Moreover, described herein are methods and systems for installing flooring systems that provide water-resistant features to the floor and walls. The flooring systems can include structural boards installed to create an ‘L’ flashing detail. In some embodiments, the boards can be adhered or otherwise joined together. The adhered boards can be covered with an acrylic resin or other suitable waterproofing agent. The resin can serve to decrease the rate that water seeps into the structural boards. In some embodiments, a fiberglass matte or other reinforcing product can be used with the resin to reinforce the water-resistant properties of the structural boards coated with the resin. In certain implementations, a subfloor adhesive or other suitable adhesive can be used to seal the joint between the structural boards forming the ‘L’ flashing detail. In some embodiments, the subfloor adhesive or other suitable adhesive can be used to join the structural boards together to form the ‘L’ flashing detail. The disclosed flooring systems can be used to waterproof and/or increase water resistance of interior floors of a building, such as a dwelling or office building. 
     Moreover, described herein are methods and systems for installing flooring systems that provide waterproofing or water-control capabilities. The flooring systems can utilize a gypsum material or any other self-leveling or concrete material along with a structural board or any other type of cement, wood, gypsum board, compressed board, cellulose fiberboard, sheathing board, or sheet metal material. The flooring systems include a waterproof coating applied to the structural boards to provide the water-control features. For example, the flooring systems can use structural boards to form a I′ flashing detail with an acrylic resin (or other waterproofing product including, for example and without limitation, cementitious material, polymers, aliphatic epoxy, urethane, polyurethane, etc.) applied over the structural boards to reduce or eliminate water seepage into the structural boards. For example, the resin can be applied to the board to repel water. In some embodiments, a fiberglass matt (or other material including, for example and without limitation, chopped strand, fiber mesh, construction sealants (e.g., POLY-G®), laminated wood panels (e.g., STRATABOND®), etc.) can be used to reinforce the waterproof properties. For example, the fiberglass mat can be used to reinforce the resin at seams, gaps, and transitions. 
     The disclosed methods include the use of structural panels, adhesive, and fasteners (e.g., ring shank coil nails). In some embodiments, the structural panels can be a cellulose fiber structural panel. For example, the cellulose fiber structural panel can be molded out of paper or other wood products (e.g., recycled post-consumer paper). The structural panels may also be referred to as isolation boards or panels due at least in part to their functionality in isolating different elements of a building (e.g., providing sound reduction, providing fire resistance, isolating poured cementitious products from fixtures or walls, etc.). 
     In certain implementations, structural or isolation boards can have a thickness of about 0.75 inches with a density of about 26-28 lbs. per cubic foot. In certain implementations, the structural or isolation boards can be between about ⅝ in. and about 1.5 in. thick. These are merely example values and isolation boards with other densities and thicknesses may be used. An example of such a board is manufactured by HOMASOTE® Company called the 440 SOUNDBARRIER®. This panel can be milled to be a targeted size (e.g., 6 in.×96 in.). In some embodiments, multiple boards can be installed on top of each other to achieve a targeted thickness (e.g., about 1.25 in., about 1.5 in., etc.). 
     The boards can be installed using any suitable combination of adhesives and/or fasteners. A typical suitable adhesive can have a base that is a synthetic rubber with polymer resins. Typically, such adhesives can have a full cure time of about 2 to 5 days. The adhesive can be applied in a designated or targeted pattern to adhere a first layer to the subfloor and to adhere a second layer to the first layer. Additional layers may also be installed in a similar fashion. 
     A typical suitable fastener includes ring shank coil nails. The ring shank coil nails can be installed using an offset pattern on a first layer of structural or isolation panels prior to placement of the adhesive to secure a second panel layer. Installation of these nails can be used to secure the first layer in place on the subfloor. Similarly, after the second layer has been secured to the first layer using the adhesive, additional nails can be used in a reverse offset pattern to secure the second layer in place while the adhesives dry and cure. The nails can be placed to create even distribution of the fasteners. For example, the fasteners can be about 8 in. on center. By applying two or more layers of the milled structural panels or boards with a ⅛″ gap between panel edges and walls, the sound and fire rating of the hybrid system is improved relative to a unitary system of just structural panels or just cementitious products. Similarly, by applying a structural panel or boards with a ⅛″ gap between a panel edge and a wall, the sound and fire rating of the hybrid system is improved relative to a unitary system of just structural panels or just cementitious products. 
     The structural panels or boards can be strategically placed during construction to achieve targeted performance characteristics for fire rating and sound rating. For example, to satisfy fire rating requirements, the structural boards can be adhered and fastened in the following non-critical areas: underneath bathtubs, closets, dead spaces, near walls, prone areas, under cabinets, under kitchen islands, and the like. In some embodiments, one or more additional layers of the structural panels can be secured to the first layer to achieve a targeted thickness to provide a pour stop for the cementitious product. Moreover, isolation boards can be installed on walls in addition to or instead of installing isolation boards to the floor, to provide the described advantages. Moreover, an acrylic resin and/or fiberglass matt can be used in conjunction with structural or isolation boards to provide waterproofing, water-resistance, and/or water-containment properties. 
     The disclosed flooring systems and methods provide a number of advantages. For example, at least some of the flooring systems enable a contractor to confidently offer warranties on the build, the warranties including water-resistance, fire-resistance, sound-resistance, mold-resistance, etc. 
     As another example of an advantage, at least some of the flooring systems prevent drywall and cabinets from sitting on a material that is curing because they are installed over structural board and/or isolated from the poured cementitious product using one or more layers and/or coatings. At least some of the flooring systems provide a physical barrier so that freshly poured gypsum concrete does not come into contact with areas of the unit that can trigger the onset of mold. Common areas where mold may occur include the drywall, base boards, and cabinetry. The disclosed perimeter isolation boards create buffer zones that reduce or eliminate mold onset. 
     As another example of an advantage, the perimeter isolation boards of at least some of the disclosed hybrid flooring systems enable a wetter floor to be poured resulting in a flatter floor. The perimeter isolation boards can be used as a screed to provide a more level surface. In addition, at least some of the flooring systems enable a contractor to pour at a slump closer to 9.5″, resulting in a flatter floor provided to the builder, resulting in less preparation time and conforming to requirements of typical finish floor applications. 
     As another example of an advantage, at least some of the flooring systems can be installed earlier in the construction process, resulting in less time on the backend schedule for curing times. The disclosed flooring systems can be installed prior to the application of drywall which results in little or no cure times after placement. Traditional construction schedules have blocked out up to 2 weeks of complete down time, resulting in relatively large costs to the builder. By installing earlier, the flooring systems reduce or eliminate this down time resulting in faster sales and increased profit to builders due at least in part to less carry costs. 
     As another example of an advantage, at least some of the flooring systems create a waterproof floor and can hold water in a unit in the event of a unit flood. The disclosed waterproof technologies can provide a water barrier system. This may particularly advantageous at the top floor of a multi-floor unit or building allowing the construction process to continue for items such as rough electrical wiring and drywall installation. In some embodiments, standing water can be removed utilizing water evacuation units placed at strategic areas throughout the building. 
     Example Hybrid Underlayment Installations 
       FIGS.  1 A,  1 B,  1 C,  1 D,  1 E,  1 F,  1 G,  1 H, and  1 I  illustrate installation of an underlayment layer  100  of flooring using boards  110 ,  112  for an inside corner binder. The flooring can be for single or multi-family housing, high and low-rise apartments and condominiums, motels, schools, professional buildings, assisted living facilities, or the like. The underlayment  100  extends between subfloor  102  and finish flooring  120 . Underlayment  100  provides several functions including moisture blockage, cushioning, sound attenuation, fire rating, insulation, structure, and the like. 
     The subfloor  102  can be a cement slab or a wood subfloor. The finish flooring  120  can be any suitable flooring such as tile, wood, laminate, carpet, or the like. The subfloor  102  can extend between walls  104  that are either external walls or internal walls for a building. 
       FIG.  1 A  illustrates the subfloor  102  and walls  104  with an adhesive  111  deposited or applied in a pattern in a first portion of the subfloor  102 . The adhesive  111  is configured to adhere an isolation board  110  to the subfloor within the first portion of the subfloor  102 . The adhesive  111  can be, for example and without limitation, a polyurethane-based, moisture-curing subfloor bonding adhesive. The adhesive material is configured to be compatible with both the material of subfloor  102  and the isolation board  110 . 
       FIG.  1 B  illustrates installation of the isolation board  110  on the applied adhesive  111 . The isolation board  110  is installed so that it lies within the first portion of the subfloor  102 . The first portion of the subfloor is a non-critical area where it is advantageous to use structural boards instead of cementitious products. Non-critical areas include, for example and without limitation, underneath bathtubs, closets, dead spaces, near walls, prone areas, under cabinets, under kitchen islands, and the like. In some embodiments, the first portion covers an area that extends less than or equal to 96 inches from the wall  104 , less than or equal to 48 inches from the wall  104 , less than or equal 24 inches from the wall  104 , less than or equal to 12 inches from the wall  104 , less than or equal to 8 inches from the wall  104 , or less than or equal to 6 inches from the wall  104 . The isolation board  110  can be installed so that there is a gap  106  between adjacent isolation boards and the wall  104 . The gap  106  can be about ⅛ inches to about 3/16 inches. The gap  106  can be configured to allow the isolation boards  110  to expand and contract. 
     The isolation board  110  can be a fiberboard, such as a cellulose fiberboard, or a gypsum-based board. The isolation board  110  can have a thickness of about ½ inch or between about ¼ inch and 1 inch. The isolation board  110  can be a fire-rated and/or sound-rated structural board tested and approved for construction purposes. Thus, the isolation board  110  can be different from the structural board  112  installed on top of the isolation board  110  because although the structural board  112  may possess similar fire-rating and sound-rating characteristics as the isolation board  110 , the structural board  112  does not need to be tested and approved for construction purposes. For example, the isolation board  110  can be required to pass construction standards whereas the structural board  112  can be used without passing the same construction standards. However, it is to be understood that the isolation board  110  and the structural board  112  can be the same board (e.g., made from the same material with the same physical properties). 
     In some embodiments, the isolation board  110  comprises two or more structural boards pressed together to form a composite board. In some embodiments, the isolation board  110  is a structural board made from cellulose fiber. An example of such a board is a board manufactured by HOMASOTE® Company called the 440 SOUNDBARRIER®. The isolation board  110  can be made using a homogeneous composition with protection against termites, rot and fungi and resistance to moisture. In some embodiments, the isolation board  110  is particleboard or fiberboard made from cellulose fibers, typically from wood, that are bonded together with a synthetic binder or resin. The isolation board  110  can be manufactured using man-made consolidated cellulosic articles, such as fiberboard, hardboard (e.g., low-density or high-density hardboard), soft board, high-density fiberboard (HDF), medium density fiberboard (MDF), chipboards, particleboard, medium-density particleboard, oriented strandboard (OSB), or the like. In some embodiments, the isolation board  110  can have a density between about 26 and about 28 lb./ft. 3 . In some embodiments, the isolation board  110  can comprise engineered wood products prepared from wood fiber extracted from chips and pulped wood waste. In certain embodiments, the isolation board  110  can have a density greater than about 50 lb/ft 3 , including values of greater than 60 lb/ft 3 , 70 lb/ft 3 , 80 lb/ft 3 , 90 lb/ft 3 , or greater than 100 lb/ft 3 . In certain implementations, to improve water resilience, processing oils can be added during the board formation under high temperature and pressure. In various embodiments, the isolation board  110  can be prepared from wood wastage fibers glued together with resin or glued under heat and pressure. In certain aspects, the isolation board  110  has a density of between about 30 lb/ft 3  and about 50 lb/ft 3 , including values of 35 lb/ft 3 , 40 lb/ft 3 , and 45 lb/ft 3 . 
       FIG.  1 C  illustrates one or more mechanical fasteners  113  (e.g., nails) being driven into the isolation board  110  to secure the isolation board  110  to the subfloor  102 . Fastening the isolation board  110  to the subfloor  102  can be used to secure the isolation board  110  in place while the adhesive  111  cures or dries. In some embodiments, the nails  113  can be wire ring shank coil nails. The nails  113  can be, in some embodiments, 1.25″×0.080 15 deg. wire ring shank coil nails. The nails  113  can be installed or driven into the isolation board  110  using a ⅛-inch countersink. The nails  113  can be annular threaded nails or screws. The nails  113  can be installed at regular intervals in an offset pattern. In some embodiments, the nails can be spaced about 8 inches to about 10 inches apart and can be positioned at least about ½ inch away from an edge of the isolation board  110 . 
     In some embodiments, the plurality of mechanical fasteners, e.g., either nails or screws, may be used to secure the isolation board  110 . In some embodiments, the isolation board  110  may be secured to the subfloor  102  via any suitable adhesive, either independently of, or in conjunction with one or more mechanical fasteners. 
       FIG.  1 D  illustrates application of another layer of the adhesive  111 .  FIG.  1 E  illustrates installation of the structural board  112  on top of the isolation board  110 . The structural board  112  can be the same material as the isolation board  110 . The structural board  112  can have the same or different thickness as the isolation board  110 . The structural board  112  and the isolation board combine to form a barrier or pour stop for the cementitious product  115 . In some embodiments, the structural board  112  is a class A, 1-hour, fire-rated, water-resistant type board. The structural board  112  can be a pressed structural type board made from either cellulose fiber, wood, sheathing, gypsum, or fiberglass matted material. The structural board  112  can be cut or milled from a board or panel, being cut into strips ranging from about 1 inch to about 48 inches in width with a thickness from about ½ inch to about 1.5 inches. In some embodiments, the structural board has a width that is greater than or equal to about 4 inches and less than or equal to about 6 inches, greater than or equal to about 3 inches and less than or equal to about 12 inches, greater than or equal to about 2 inches and less than or equal to about 24 inches, or greater than or equal to about 1 inches and less than or equal to about 48 inches. 
     The structural board  112  and the isolation board  110  can be selected, milled, and stacked so that corresponding edges of each board align with one another. This can be done to maintain the gap  106  between adjacent boards and the wall  104 . However, in some embodiments as described herein, the isolation board  110  and the structural board  112  can be offset from one another. 
       FIG.  1 F  illustrates one or more nails  113  being driven into the structural board  112  to secure the structural board  112  to the isolation board  110 . Fastening the structural board  112  to the isolation board  110  can be used to secure the structural board  112  in place while the adhesive  111  cures or dries. 
       FIG.  1 G  illustrates installation of drywall  105  over the top layer of the underlayment  100 . The drywall  105  can be configured to be installed on top of the structural board  112 . In some embodiments, the drywall  105  can be installed in a gap between the wall  104  and the combination of the isolation board  110  and the structural board  112  so that the drywall  105  and the combined boards are butted up to one another. 
       FIG.  1 H  illustrates a cementitious product  115  installed onto the flooring system of  FIGS.  1 A- 1 F . After the installation procedure described and illustrated in  FIGS.  1 A- 1 F  (and before or after installation of the drywall  105  in  FIG.  1 G ), the cementitious product  115  can be poured to form a poured underlayment that abuts an edge of the combination of the isolation board  110  and the structural board  112  and, preferably, adheres thereto. The term “pour” is used broadly herein to encompass any suitable method for applying the cementitious product  115  so that the cementitious product  115  is directed to flow, or spread, over the subfloor  102 . In some embodiments, the area over which the cementitious product  115  is to be poured can be primed prior to pouring. The primer can be applied for example, via spraying or rolling, according to known methods. 
     The cementitious product  115  can be a self-leveling gypsum cement or other cementitious lightweight concrete. The term light-weight concrete is used herein as a generic description for a concrete topping that is less dense than standard concrete. An example of the cementitious product  115  includes a material commonly referred to as gypsum concrete or gyp-crete. Gyp-crete is a building material that can be used as a floor underlayment in wood-frame and concrete construction for fire ratings, sound reduction, radiant heating, and floor leveling. Gyp-crete comprises atmospheric calcined gypsum, sand, water, and small amounts of various additives. Additives may include polyvinyl alcohol, an extender such as sodium citrate or fly ash, a surfactant such as colloid defoamer 1513 DD made by Colloids, Inc., and a fluidizer based on sodium or potassium derivatives of naphthalene sulfonate formaldehyde condensate. 
     The combination of the structural board  112  and the isolation board  110  form a barrier to the cementitious product as it is poured. The cementitious product  115  can be poured until it is level with a top side of the structural board  112  to form a level underlayment  100 . Thus, the isolation board  110  (in combination with the structural board  112 ) can cover a first portion of the subfloor  102  while the cementitious product  115  can cover a second portion of the subfloor  102 . In total, the first portion and the second portion can make up the entire area of the subfloor  102 , or the total area of the subfloor  102  that is to receive the underlayment  100 . 
     In some embodiments, the first portion can be divided into various locations, wherein individual first portion locations have a size approximately equal to a footprint of a fixture, for example, a bathtub, a closet, a kitchen island, cabinets, or the like. The first portion may be designated as a pre-pour area where the isolation board  110  and the structural board  112  is laid prior to installing the fixture. The second portion is located adjacent to the first portion, making up the remainder of the subfloor  102 . The second portion is left substantially exposed for the installation of the poured cementitious product  115 . 
       FIG.  1 I  illustrates the underlayment  100  wherein two structural boards  112   a ,  112   b  are used to achieve a targeted thickness. Thus, one or more structural boards  112  can be used to achieve the targeted thickness. Additionally, after the underlayment  100  has been installed, finish flooring  120  can be installed to finish installation of the flooring system. It should also be understood, although not illustrated in  FIGS.  1 A- 1 I , that a single isolation board  110  can be used to achieve the targeted thickness rather than using a combination of an isolation board with one or more structural boards. 
       FIGS.  2 A,  2 B,  2 C,  2 D,  2 E, and  2 F  illustrate another example installation of an underlayment layer  200  of flooring using fiberboards for a perimeter board binder. The installation follows the same installation steps described herein with reference to  FIGS.  1 A- 1 F  except that the structural board  112  is installed offset from the isolation board  110  so that the gap  206   a  between adjacent isolation boards  110  does not align with the gap  206   b  between adjacent structural boards  112 . 
       FIG.  2 A  illustrates application of the adhesive  111  to the subfloor  102 .  FIG.  2 B  illustrates installation of the isolation boards  110  on the subfloor  102 .  FIG.  2 C  illustrates using mechanical fasteners  113  to secure the isolation board  110  to the subfloor  102  to allow the adhesive  111  to dry.  FIG.  2 D  illustrates application of the adhesive  111  to a topside of the isolation boards  110 .  FIG.  2 E  illustrates installation of the structural boards  112  on top of the isolation boards  110  so that they are offset horizontally from one another. That is, the edges of the isolation boards  110  and the structural boards  112  closest to the wall  104  are aligned, the edges of the isolation boards  110  and the structural boards  112  furthest from the wall  104  are aligned, but the perpendicular edges to these are not aligned so that gap  206   a  and gap  206   b  are not aligned.  FIG.  2 F  illustrates using mechanical fasteners  113  to secure the structural boards  112  to the isolation boards  110  to allow the adhesive  111  to dry. 
       FIGS.  3 A and  3 B  illustrate another example installation of an underlayment layer  300  under a bathroom tub.  FIG.  3 A  illustrates the subfloor  102  and walls  104  with the adhesive  111  illustrated to adhere the first layer of isolation boards  110 , similar to the installation process described herein with reference to  FIG.  1 A . 
       FIG.  3 B  illustrates after the underlayment installation procedure has been completed. The underlayment  300  includes isolation boards  110  installed in a first portion of the subfloor  102 , structural boards  112  installed on top of, and aligned with, the isolation boards  110 . Although a single layer of structural boards  112  is illustrated, two or more layers of structural boards  112  can be installed, similar to the installation described herein with reference to  FIG.  1 I . Each structural board  112  can have a different thickness from each other or the same thickness. Similarly, one or more structural boards  112  can have the same thickness as the isolation board  110 . In some embodiments, a single layer of isolation boards  110  may be used to achieve a targeted thickness rather than using a combination of isolation boards and structural boards. In this way, the isolation board  110  and/or a combination of the isolation board  110  and one or more structural boards  112  can be used to build a pour barrier to a targeted thickness corresponding to a targeted thickness of the cementitious product  115 . 
     The underlayment  300  includes the poured cementitious product  115  poured and installed in the second portion of the subfloor  102 . Prior to pouring the cementitious product  115 , a sound control membrane  114  can be installed in the second portion of the subfloor  102 . The sound control membrane  114  can be configured for sound control, sound attenuation, and/or sound abatement. The sound control membrane  114  may also function as a vapor barrier and may include a sheet of polyethylene film resting upon the reinforced-concrete subfloor  102 . The sound control membrane  114  may supplied in rolls and have adhesive-backed edges for overlapping with one another to secure the abutting edges together. In some embodiments, as shown here, a separate tape material  116  may be used for this purpose. The sound control membrane  114  may be formed from fused entangled filaments of a nylon material attached to a non-woven nylon fabric, or from blends of polymeric fibers having a nylon reinforcement. The tape material  116  may be, e.g., duct tape, poly-stucco tape, cloth tape, scrim-backed tape, or pressure-sensitive tape. The tape material  116  may be coated with polyethylene. 
     Caulking  117  is applied to any component that penetrates through the isolation boards and/or subfloor  102 . The caulking  117  can be, e.g., fire-rated caulking and can be installed or applied around piping and any gaps larger than about 3/16 inches. Caulking  117  can be applied to help with expansion and for places that require penetration. 
     A sealant  119  may be applied at intersection locations between structural boards  112  and/or intersections between the structural boards  112  and the cementitious product  115 . The sealant  119  can be applied on top of the cementitious product  115  and the structural boards  112  to protect the seam to make it smooth for finish flooring installed on the top thereof. 
       FIGS.  4 A and  4 B  illustrate another example installation of an underlayment layer  400  under a closet. The installation follows the same installation steps described herein with reference to  FIGS.  3 A and  3 B  but for a different portion of a building (e.g., under a closet rather than under a bathtub). The corresponding callouts reference the same components so a description of these components will not be repeated again for the sake of conciseness. 
       FIGS.  5 A and  5 B  illustrate another example installation of an underlayment layer  500  for an outside corner binder. The installation follows the same installation steps described herein with reference to  FIGS.  3 A and  3 B  but for a different portion of a building (e.g., an outside corner binder rather than under a bathtub). The corresponding callouts reference the same components so a description of these components will not be repeated again for the sake of conciseness. 
       FIGS.  6 A and  6 B  illustrate installation of an underlayment layer  600  for an inside corner binder. The installation follows the same installation steps described herein with reference to  FIGS.  3 A and  3 B  but for a different portion of a building (e.g., an inside corner binder rather than under a bathtub). The corresponding callouts reference the same components so a description of these components will not be repeated again for the sake of conciseness. 
       FIGS.  7 A and  7 B  illustrate installation of an underlayment layer  700  for an island in a kitchen. The installation follows the same installation steps described herein with reference to  FIGS.  3 A and  3 B  but for a different portion of a building (e.g., under an island in the kitchen rather than under a bathtub). The corresponding callouts reference the same components so a description of these components will not be repeated again for the sake of conciseness. 
       FIGS.  8 A and  8 B  illustrate installation of an underlayment layer  800  of flooring in a dwelling. The installation follows the same installation steps described herein with reference to  FIGS.  3 A- 7 B  but are for an entire dwelling, including all the locations described in  FIGS.  3 A- 7 B . The dwelling is a studio-style apartment, but the disclosed installation steps can be applied to various other building and dwelling types. The corresponding callouts reference the same components so a description of these components will not be repeated again for the sake of conciseness. 
       FIGS.  9 A,  9 B,  9 C,  9 D,  9 E, and  9 F  illustrate another example installation of an underlayment layer  900  of flooring using isolation and structural boards for an outside corner binder. The installation follows the same installation steps described herein with reference to  FIGS.  2 A- 2 F  but are for a different portion of a building (e.g., an outside corner binder rather than a perimeter binder). 
       FIG.  9 A  illustrates application of the adhesive  111  to the subfloor  102 .  FIG.  9 B  illustrates installation of the isolation boards  110  on the subfloor  102 .  FIG.  9 C  illustrates using mechanical fasteners  113  to secure the isolation board  110  to the subfloor  102  to allow the adhesive  111  to dry.  FIG.  9 D  illustrates application of the adhesive  111  to a topside of the isolation boards  110 .  FIG.  9 E  illustrates installation of the structural boards  112  on top of the isolation boards  110  so that they are offset horizontally from one another.  FIG.  9 F  illustrates using mechanical fasteners  113  to secure the structural boards  112  to the isolation boards  110  to allow the adhesive  111  to dry. 
       FIGS.  10 A,  10 B,  10 C,  10 D,  10 E,  10 F, and  10 G  illustrate another example installation of an underlayment layer  1000  of flooring using isolation and structural boards as a bathtub binder. The installation follows the same installation steps described herein with reference to  FIGS.  2 A- 2 F  but are for a different portion of a building (e.g., underneath a bathtub in a finished building rather than a perimeter binder). 
       FIG.  10 A  illustrates application of the adhesive  111  to the subfloor  102 .  FIG.  10 B  illustrates installation of the isolation boards  110  on the subfloor  102 .  FIG.  10 C  illustrates using mechanical fasteners  113  to secure the isolation board  110  to the subfloor  102  to allow the adhesive  111  to dry.  FIG.  10 D  illustrates application of the adhesive  111  to a topside of the isolation boards  110 .  FIG.  10 E  illustrates installation of the structural boards  112  on top of the isolation boards  110  so that they are offset horizontally from one another.  FIG.  10 F  illustrates using mechanical fasteners  113  to secure the structural boards  112  to the isolation boards  110  to allow the adhesive  111  to dry. 
       FIG.  10 G  illustrates a pipe penetration for the bathtub to be installed over the isolation boards  110 . The pipe  1030  penetrates through the isolation boards  110  and the subfloor  102 . The pipe  1030  includes foam insulation  1032  or fire-rated caulking  1032  between the pipe  1030  and the isolation boards  110 , similar to the embodiment described herein with reference to  FIG.  3 B . 
       FIGS.  11 A,  11 B,  11 C,  11 D, and  11 E  illustrate another example installation of an underlayment layer  1100  of flooring using fiber boards as a bedroom closet binder. The installation follows the same installation steps described herein with reference to  FIGS.  2 A- 2 F  with one or more installation steps removed for the sake of brevity. The installation differs from that described with reference to  FIGS.  2 A- 2 F  because it is for a different portion of a building (e.g., the flooring in a non-walk-in closet rather than a perimeter binder). 
       FIG.  11 A  illustrates application of the adhesive  111  to the subfloor  102 .  FIG.  11 B  illustrates installation of the isolation boards  110  on the subfloor  102 .  FIG.  11 C  illustrates application of the adhesive  111  to a topside of the isolation boards  110 .  FIG.  11 D  illustrates installation of the structural boards  112  on top of the isolation boards  110  so that they are offset horizontally from one another.  FIG.  11 E  illustrates using mechanical fasteners  113  to secure the structural boards  112  to the isolation boards  110  to allow the adhesive  111  to dry. 
       FIGS.  12 A,  12 B,  12 C,  12 D,  12 E, and  12 F  illustrate another example installation of an underlayment layer  1200  of flooring using isolation and structural boards as a kitchen island binder. The installation follows the same installation steps described herein with reference to  FIGS.  2 A- 2 F  but are for a different portion of a building (e.g., underneath a kitchen island or cabinets in a finished building rather than a perimeter binder). 
       FIG.  12 A  illustrates application of the adhesive  111  to the subfloor  102 .  FIG.  12 B  illustrates installation of the isolation boards  110  on the subfloor  102 .  FIG.  12 C  illustrates using mechanical fasteners  113  to secure the isolation board  110  to the subfloor  102  to allow the adhesive  111  to dry.  FIG.  12 D  illustrates application of the adhesive  111  to a topside of the isolation boards  110 .  FIG.  12 E  illustrates installation of the structural boards  112  on top of the isolation boards  110  so that they are offset horizontally from one another.  FIG.  12 F  illustrates using mechanical fasteners  113  to secure the structural boards  112  to the isolation boards  110  to allow the adhesive  111  to dry. 
       FIGS.  13 A,  13 B,  13 C,  13 D, and  13 E  illustrate a plan view of an installation of an underlayment layer  1300  of flooring in a dwelling. The dwelling is a studio-style apartment, but the disclosed installation steps can be applied to various other building and dwelling types. The installation follows the same installation steps described herein with reference to  FIGS.  2 A- 2 F  but includes all of the disclosed binders rather than just a perimeter binder. 
     The disclosed installation in  FIGS.  13 A- 13 E  illustrates that a first portion of the subfloor  102  which is configured to receive the isolation boards  110  can be divided among different rooms and need not be a continuous area. For example, disjointed first portions can be installed for a kitchen island. In addition, it can be seen that the first portion can include the prone areas of the dwelling so that isolation boards  110  and structural boards  112  are installed around the interior perimeter of each room and for other non-critical areas such as kitchen islands, cabinets, underneath bathtubs, in closets, and the like. Thus, the subfloor  102  of a dwelling is typically divided among various rooms, and, particularly in a multi-family dwelling, can have multiple pre-pour, or first portion areas of the subfloor  102 . 
       FIG.  13 A  illustrates application of the adhesive  111  to the subfloor  102 .  FIG.  13 B  illustrates installation of the isolation boards  110  on the subfloor  102 .  FIG.  13 C  illustrates using mechanical fasteners  113  to secure the isolation boards  110  to the subfloor  102  to allow the adhesive  111  to dry.  FIG.  13 D  illustrates installation of the structural boards  112  on top of the isolation boards  110  so that they are offset horizontally from one another.  FIG.  13 E  illustrates using mechanical fasteners  113  to secure the structural boards  112  to the isolation boards  110  to allow the adhesive  111  to dry. 
     Example Hybrid Underlayment Installation Methods 
       FIG.  14    illustrates a flow chart of an example method  1400  for installing a hybrid underlayment of boards and a cementitious product. The isolation and structural boards and cementitious product have been described elsewhere herein, so further description of these items will be omitted here for conciseness in the description. 
     Prior to installing the underlayment layer, a worker can ensure the installation area is swept and clean of debris throughout corners and center. The substrate (e.g., subfloor) can be inspected for delamination and excessive sagging prior to installation of the underlayment. In addition, the worker can confirm the overall thickness of the underlayment, and specifically the targeted thickness of the cementitious product. The structural barrier formed by the isolation board alone or in combination with one or more structural boards should be configured to achieve the targeted thickness of the cementitious product. The isolation board and/or the structural boards are fire-rated and/or sound-rated. The worker may also measure wall length or targeted length and pre-cut the isolation boards and/or the structural boards to the measured length. In addition, the worker may place the isolation board on top of the subfloor, pushing firmly against wall to evaluate and to confirm panel placement. 
     In block  1405 , a worker applies adhesive to adhere an isolation board to the subfloor in a targeted area. The targeted area is located within a first portion of the subfloor where the cementitious product will not be poured (e.g., a pre-pour area). The adhesive can be applied to the subfloor, to an underside of the isolation board, or to both. The worker can apply a pattern of adhesive to the subfloor and/or to the underside of the isolation board. 
     In block  1410 , the worker installs the isolation board to the subfloor with the adhesive so that there is a gap between adjacent isolation boards and any walls. The worker can press the isolation board in place to secure it to the subfloor with the adhesive. This step can be repeated as necessary to obtain targeted coverage with the isolation boards to complete a first installation layer. This step can be repeated for the first layer by installing a plurality of isolation boards edge-to-edge to cover the first portion of the subfloor. 
     In addition, a worker may secure the first layer of isolation board to the subfloor using mechanical fasteners such as nails. Nails can be installed using a linear pattern about 8 inches to about 10 inches apart and about ½ inch from the edge of the isolation board with a ⅛-inch countersink to create an even distribution of pressure and to allow the second layer to be properly placed without obstruction. 
     Once the first layer of isolation boards has been installed, a second layer can be installed (if necessary). Installation follows the same pattern, but nails are offset from nails in first layer. For example, in block  1415 , adhesive is applied to adhere a bottom side of the structural boards to a top side of the installed isolation boards. In block  1420 , a worker installs the structural board on top of the installed isolation boards. Gaps between boards can be aligned vertically or they can be offset. This completes a second layer of the flooring installation, covering the first portion of the subfloor. This process can be repeated to build up a targeted thickness that matches the targeted thickness of the cementitious product pour. The first portion of the subfloor can include areas such as cabinets, closets, bathtubs, areas near walls and/or other dead spaces. In some embodiments, the worker can place caulking and/or isolating foam at all pipe penetrations or other penetrations. 
     In block  1425 , the worker pours cementitious product in a second portion of the subfloor so that it is level with a top side of the uppermost structural board. This is done to create an even and level underlayment. The method  1400  may also include applying sealant to seams between the combined isolation and structural boards and the cementitious product. This can be done to enhance the levelness of the underlayment. In some instances, a sound mat may be laid over the second portion of the subfloor prior to pouring the cementitious product. Once the flooring system has been installed using the method  1400 , construction schedule may commence with installations such as drywall, cabinets, and trim as early as within 24 hours after the final pour. 
     Example Flooring Installations with Isolation Boards 
       FIG.  15    illustrates a cross-section of flooring  1500  having floor isolation boards  1510  and a cementitious product  115  forming an underlayment layer. The flooring  1500  is similar to the underlayment  100  described herein with reference to  FIGS.  1 A- 1 I , so description of common elements (as indicated by shared callout numbers) are omitted. The floor isolation boards  1510  are similar to the combination of the isolation board  110  and the structural board  112  illustrated and described herein with reference to  FIG.  1 H , with a difference being a single isolation board  1510  being used to achieve the desired or targeted height for the pour stop of the cementitious product  115 . However, it is to be understood that the flooring  1500  can be constructed using a combination of isolation boards and structural boards, as described elsewhere herein. The isolation boards  1510  can be, for example, about 1.25 inches or about 1.5 inches thick, depending on construction details and specifications. Other thickness may be used as well. The isolation boards  1510  can be milled and manufactured to have a targeted height (or thickness). The isolation boards  1510  can be fire-rated and/or sound-rated structural boards tested and approved for construction purposes. 
     In some embodiments, the isolation board  1510  is a structural board made from cellulose fiber. An example of such a board is a board manufactured by HOMASOTE® Company called the 440 SOUNDBARRIER®. The isolation board  1510  can be made using a homogeneous composition with protection against termites, rot and fungi and resistance to moisture. In some embodiments, the isolation board  1510  is particleboard or fiberboard made from cellulose fibers, typically from wood, that are bonded together with a synthetic binder or resin. The isolation board  1510  can be manufactured using man-made consolidated cellulosic articles, such as fiberboard, hardboard (e.g., low-density or high-density hardboard), soft board, high-density fiberboard (HDF), medium density fiberboard (MDF), chipboards, particleboard, medium-density particleboard, oriented strandboard (OSB), or the like. In some embodiments, the isolation board  1510  can be a gypsum-based board. In some embodiments, the isolation board  1510  can have a density between about 26 and about 28 lb./ft. 3 . In some embodiments, the isolation board  1510  can comprise engineered wood products prepared from wood fiber extracted from chips and pulped wood waste. In certain embodiments, the isolation board  1510  can have a density greater than about 50 lb/ft 3 , including values of greater than 60 lb/ft 3 , 70 lb/ft 3 , 80 lb/ft 3 , 90 lb/ft 3 , or greater than 100 lb/ft 3 . In certain implementations, to improve water resilience, processing oils can be added during the board formation under high temperature and pressure. In various embodiments, the isolation board  1510  can be prepared from wood wastage fibers glued together with resin or glued under heat and pressure. In certain aspects, the isolation board  1510  has a density of between about 30 lb/ft 3  and about 50 lb/ft 3 , including values of 35 lb/ft 3 , 40 lb/ft 3 , and 45 lb/ft 3 . 
     The isolation boards  1510  can be secured to the subfloor  102  using any suitable combination of adhesives and/or mechanical fasteners. Examples of adhesives are provided elsewhere herein. Similarly, examples of mechanical fasteners are provided elsewhere herein. A gap  106  can be provided between the isolation boards  1510  and the wall  104 , as described elsewhere herein. Drywall  105  can be installed on top of the isolation boards  1510 , as described in greater detail with reference to  FIG.  1 G . 
     The flooring  1500  can also include the sound control membrane  114 , as described elsewhere herein. The sound control membrane  114  can be placed and/or secured to the subfloor  102 . Multiple pieces of a sound control membrane or mat can be attached together (e.g., at seams) to form the sound control membrane  114 . In some embodiments, a tape material can be used to attach separate pieces of the sound control membrane together. 
     A bonding adhesive in the form of a tape material  1518  can be applied to a face of the isolation board  1510  and to a portion of the sound control membrane  114 . The tape material  1518  can be configured to bond the sound control membrane  114  to the isolation board  1510 . Installed in this manner, the cementitious product  115  can be poured to a targeted height (e.g., a height or thickness of the isolation boards  1510 ). The tape material  1518  can be configured to provide a physical barrier to inhibit or prevent leaks of the cementitious product  115  penetrating under the sound-control membrane  114  and/or the isolation boards  1510 . 
     Finish flooring  120  can then be installed to complete the flooring  1500 . In addition, the flooring can include a sealant (as described elsewhere herein) and/or caulking (as described elsewhere herein) at intersections between isolation boards, on components that penetrate through the isolation boards  1510  and the subfloor  102 , and/or at intersections between isolation boards  1510  and the cementitious product  115 , etc. 
       FIG.  16    illustrates a cross-section of flooring  1600  having floor isolation boards  1510 , wall isolation boards  1601 , and a cementitious product  115 . The flooring  1600  is similar to the flooring  1500  with the addition of the wall isolation boards  1601 , thus elements described elsewhere herein will not be described again for the sake of conciseness and clarity. There can be a gap between the floor isolation boards  1510  and the wall isolation boards  1601  or there can be no gap (as illustrated). The floor isolation boards  1510  can be a single panel or a stack of panels, as described herein with reference to  FIGS.  1 H and  1 I , for example. Similarly, the wall isolation boards  1601  can be stacked boards (e.g., extending outward starting from the wall  104 ) or unstacked. The wall isolation boards  1601  can be the same type of board as the floor isolation boards  1510  or may be any suitable structural or isolation panel described herein. In certain embodiments, the wall isolation boards  1601  can be fire-rated and/or sound-rated structural boards tested and approved for construction purposes, similar to the isolation boards described elsewhere herein. The wall isolation boards  1601  can have a thickness of about 0.625 inches (e.g., ⅝ in.) or between about 0.5 in. and about 1.5 in., between about 0.6 in. and about 1.25 in., or between about 0.75 in. and about 1 in. In some embodiments, the wall isolation boards  1601  can have a thickness that is less than the thickness of the floor isolation boards  1510 . The wall isolation boards  1601  can have a height of about 6 in., or at least about 2 in. and/or less than or equal to about 12 in., at least about 4 in. and/or less than or equal to about 10 in., or at least about 5 in. and/or less than or equal to about 8 in. Drywall  105  can be installed over (e.g., above) the wall isolation boards  1601 . 
     The flooring  1600  can also include a sound control membrane  114 , as described elsewhere herein. The sound control membrane  114  can be placed and/or secured to the subfloor  102 . Multiple pieces of a sound control membrane or mat can be attached together (e.g., at seams) to form the sound control membrane  114 . In some embodiments, a tape material can be used to attach separate pieces of the sound control membrane together. 
     A bonding adhesive in the form of a tape material  1518  can be applied to a face of the isolation board  1510  and to a portion of the sound control membrane  114 . The tape material  1518  can be configured to bond the sound control membrane  114  to the isolation board  1510 . Installed in this manner, the cementitious product  115  can be poured to a targeted height (e.g., a height or thickness of the isolation boards  1510 ). The tape material  1518  can be configured to provide a physical barrier to inhibit or prevent leaks of the cementitious product  115  penetrating under the sound-control membrane  114  and/or the isolation boards  1510 . 
     Finish flooring  120  can then be installed to complete the flooring  1600 . In addition, the flooring  1600  can include a sealant (as described elsewhere herein) and/or caulking (as described elsewhere herein) at intersections between isolation boards  1510 , on components that penetrate through the isolation boards  1510  and the subfloor  102 , at intersections between isolation boards  1510  and the cementitious product  115 , at intersections between isolation boards  1510  and wall isolation boards  1601 , etc. 
       FIG.  17    illustrates a cross-section of flooring  1700  having wall isolation boards  1601  and a cementitious product  115 . The flooring  1700  is similar to the flooring  1600  without the inclusion of floor isolation boards  1510 . The wall isolation boards  1601  can be installed by securing the wall isolation boards  1601  to the wall  104  using mechanical fasteners (e.g., drywall screws, nails, etc.) and/or adhesives, as described elsewhere herein. With the wall isolation boards  1601  installed, a perimeter isolation strip  1719  can be secured to the wall isolation boards  1601 . The perimeter isolation strip  1719  can be a tape material that provides, enhances, or assists with the isolation properties of the wall isolation boards  1601 . Drywall  105  can be installed over (e.g., above) the wall isolation boards  1601 . 
     The flooring  1700  can also include a sound control membrane  114 , similar to the sound control membrane  114  described elsewhere herein. A bonding adhesive in the form of a tape material  1518  can be applied to a portion of the sound control membrane  114 . Installed in this manner, the cementitious product  115  can be poured to a targeted height. The targeted height can be higher than a height of the perimeter isolation strip  1719 , the same height as the perimeter isolation strip  1719 , or below the height of the perimeter isolation strip  1719 . Finish flooring  120  can then be installed to complete the flooring  1700 . In addition, the flooring can include a sealant (as described elsewhere herein) and/or caulking (as described elsewhere herein) at intersections between wall isolation boards  1601 , on components that penetrate through the subfloor  102 , and/or at intersections between wall isolation boards  1601  and the cementitious product  115 . 
     Example Flooring Installations with Water-Control Features 
       FIG.  18    illustrates a cross-section of flooring  1800  having floor isolation boards  1510 , wall isolation boards  1601 , and a cementitious product  115  forming an underlayment layer, similar to the flooring  1600  described herein with reference to  FIG.  16   . However, the flooring  1800  also includes a waterproof coating  1822  to provide water-control features to the flooring  1800 . The flooring  1800  is similar to the underlayment  100  described herein with reference to  FIGS.  1 A- 1 I , so description of common elements (as indicated by shared callout numbers) are omitted. The floor isolation boards  1510  are similar to the combination of the isolation board  110  and the structural board  112  illustrated and described herein with reference to  FIG.  1 H , with a difference being a single isolation board  1510  being used to achieve the desired or targeted height for the pour stop of the cementitious product  115 . However, it is to be understood that the flooring  1500  can be constructed using a combination of isolation boards and structural boards, as described elsewhere herein. The isolation boards  1510  can be, for example, about 1.25 inches or about 1.5 inches thick, depending on construction details and specifications. Other thickness may be used as well. The isolation boards  1510  can be milled and manufactured to have a targeted height (or thickness). The isolation boards  1510  can be fire-rated and/or sound-rated structural boards tested and approved for construction purposes. The wall isolation boards  1601  can be stacked boards (e.g., extending outward starting from the wall  104 ) or unstacked. The wall isolation boards  1601  can be the same type of board as the floor isolation boards  1510  or may be any suitable structural or isolation panel described herein. In certain embodiments, the wall isolation boards  1601  can be fire-rated and/or sound-rated structural boards tested and approved for construction purposes, similar to the isolation boards described elsewhere herein. 
     The flooring  1800  is configured to provide water-control features. This may be advantageous in constructing multifamily housing. The flooring  1800  increases performance in areas deemed high risk of wicking water into drywall due at least in part to prevention or inhibition of mold by providing physical barriers to water and mold. In particular, the combination of elements of the flooring  1800  enable water-containment and/or water-proofing of a unit. The flooring  1800  uses the combination of the cementitious product  115  (e.g., a self-leveling material or other concrete material) with the disclosed isolation boards  1510 ,  1601  (e.g., any type of cement, wood, gypsum, compressed, sheathing board or sheet metal material), as disclosed herein, and adds a waterproof coating, fiberglass, caulking and adhesives to provide the advantageous water-control features. The flooring  1800  can be used to waterproof interior floors of a building. This can inhibit or prevent water seepage into boards. This can also provide water-containment within a unit, thereby protecting adjacent units and/or floors underneath the unit from water that is contained in the unit. For example, the flooring  1800  creates a waterproof protection assembly for an interior floor of a building that can keep water contained to a single floor. The flooring  1800  may also advantageously protect the building in which it is installed during winter construction. A building with the flooring  1800  has the ability to hold water on all its floors thereby protecting tenants from water overflows from bathtubs, washers, dishwashers, etc. 
     The flooring  1800  creates an ‘L’ flashing detail using the wall isolation board  1601  and the floor isolation board  1510  to create a physical barrier between the wall  104  and the cementitious product  115  (when poured). These boards can be installed so that they butt up to one another to form the ‘L’ flashing detail. Each of the wall isolation board  1601  and the floor isolation board  1510  can be treated (e.g., coated) to inhibit the growth of mold. In some embodiments, the wall isolation board  1601  and/or the floor isolation board  1510  can be Class A, one (1) hour, fire-rated, water resistant, pressed structural board (e.g., fiberboards from HOMASOTE®, fiberglass mat gypsum sheathing (e.g., DENSGLASS®), sheet metal, carbon fiber, etc.) made from cellulose fiber. The boards may be, in some implementations, about ⅝″ thick and weighted at about 1.2 lb/sq. ft (per ½″ of thickness), however other thicknesses may be used as described herein. In some embodiments, the boards can be cut into strips ranging from about 4′×1″ through about 4′×25″, however other sizes may also be utilized as described herein. In some embodiments, the wall isolation board  1601  extends about 6″ up the wall  104  and the floor isolation board  1510  extends about 4″ onto the subfloor  102  to create the ‘L’ flashing detail, however other sizes of the isolation boards may be used as described in greater detail herein. For example, the wall isolation board  1601  can extend at least about 1″ up the wall and/or less than or equal to about 10′ up the wall, at least about 3″ up the wall and/or less than or equal to about 5′ up the wall, or at least about 6″ up the wall and/or less than or equal to about 1′ up the wall. For example, the floor isolation board  1510  can extend at least about 1″ onto the subfloor  102  and/or less than or equal to about 10′ onto the subfloor  102 , at least about 2″ onto the subfloor  102  and/or less than or equal to about 5′ onto the subfloor  102 , or at least about 4″ onto the subfloor  102  and/or less than or equal to about 1′ onto the subfloor  102 . The wall isolation board  1601  and/or the floor isolation board  1510  can be at least about 0.25″ thick and/or less than or equal to about 3″ thick, at least about 0.5″ thick and/or less than or equal to about 2″ thick, or at least about 0.625″ thick and/or less than or equal to about 1.5″ thick. 
     The wall isolation board  1601  can be adhered and/or fastened to the wall  104 . The floor isolation board  1510  can be adhered and/or fastened to the subfloor  102 . In some embodiments, the wall isolation board  1601  can be adhered and/or fastened to the floor isolation board  1510 . The adhesive used can be configured to bond boards to the subfloor, wall, and/or to one another. The adhesive can be polyurethane based, such as a moisture-curing subfloor bonding adhesive. 
     An optional layer of isolation foam  1826  can be included between the wall isolation board  1601  and the floor isolation board  1510 . The isolation foam  1826  may be used as a sound-isolation product to inhibit sound from passing from the floor up the wall. The isolation foam  1826  may be any suitable foam material that can be used to inhibit sound transmission. The isolation foam  1826  may be about 0.25″ thick, however other thicknesses may also be used. 
     A waterproof layer  1822  can be provided that runs at least partially up the wall isolation board  1601  and extends onto the subfloor  102 , covering the floor isolation board  1510 . The waterproof layer  1822  is configured to seal seams between the floor isolation board  1510  and the subfloor  102  and to seal seams between the floor isolation board  1510  and the wall isolation board  1601 . The waterproof layer  1822  can be a waterproof coating that repels water with reinforcement at seams between boards. The waterproof layer  1822  can include, for example and without limitation, a single component acrylic (e.g., cementitious, polymer, aliphatic epoxy, urethane, polyurethane) waterproof resin that repels water. The waterproof layer  1822  may also include a mat or other material to reinforce the waterproof resin. For example, the waterproof layer  1822  may also include, for example and without limitation, a fiberglass matt, fiberglass chopped strand, fiber mesh, construction sealants (e.g., POLY-G®), laminated wood panels (e.g., STRATABOND®), etc.) to reinforce the waterproof properties of the waterproof resin. 
     The waterproof layer  1822  can be applied over the floor isolation board  1510  up onto at least a portion of the wall isolation board  1601  (e.g., to extend over the seam between the boards) and onto the subfloor  102  (e.g., to extend over the seam between the board and the subfloor). The waterproof layer  1822  can be configured to inhibit water from seeping into the boards  1510 ,  1601 . In some embodiments, the waterproof layer goes up the wall isolation board about 1″ to about 1.5″, but may extend higher or lower than that. In some embodiments, the waterproof layer  1822  can also be installed to bridge gaps between floor isolation boards installed under fixtures or in other locations in the building, as described elsewhere herein, to protect cabinets, bathtubs, closets, dead spaces, etc. 
     As described elsewhere herein, the flooring  1800  may also include a sound membrane  114  that is taped in place using the tape  1518 . The cementitious product  115  can be poured as described elsewhere herein in preparation for the finish flooring  120 . 
     In some embodiments, the flooring  1800  includes a cement topping  1824  to level the flooring  1800 . The cement topping  1824  can include, for example and without limitation, ARDEX®, TUFF SKIN®, self-leveling cement, and/or other such polymer cement types of products. 
       FIG.  19    illustrates a cross-section of flooring  1900  having wall isolation boards  1601  and a cementitious product  115  forming an underlayment layer, and includes a waterproof coating  1822  to provide water-control features to the flooring  1900 . The flooring  1900  is similar to the flooring  1800  described herein with reference to  FIG.  18   , but without floor isolation boards. Thus, the flooring  1900  includes wall isolation boards  1601  adhered and/or fastened to the wall  104 . The flooring  1900  includes the waterproof layer  1822 , but in the flooring  1900  the waterproof layer covers at least a portion of the face of the wall isolation boards  1601 , up to a desired height (e.g., at least about 1″ and/or less than or equal to about 3″, at least about 1.25″ and/or less than or equal to about 2.5″, or at least about 1.5″ and/or less than or equal to about 2″) and extends onto the subfloor  102  to cover the seam between the wall isolation board  1601  and the subfloor  102 . This provides water-containment and water-control features similar to the flooring  1800 , as described elsewhere herein. The other features of flooring  1900  have been described elsewhere herein and will not be repeated here for the sake of conciseness and clarity. 
       FIG.  20    illustrates a cross-section of flooring  2000  to illustrate that any of the flooring embodiments that include wall isolation boards described herein (e.g.,  FIGS.  16 - 19   ) can be installed over drywall attached to a wall frame  104   a ,  104   b . The flooring  2000  includes the subfloor and internal walls  104   a ,  104   b . Installed on the internal walls  104   a ,  104   b  are inner drywall  2025   a ,  2025   b . In installations like these, wall isolation boards  1601   a ,  1601   b  can be attached to the inner drywall  2025   a ,  2025   b  to provide any of the features and advantages described herein with respect to the flooring of  FIGS.  16 - 19   . Above the wall isolation boards  1601   a ,  1601   b , outer drywall  105   a ,  105   b  can be installed, as described elsewhere herein. It is to be understood that inner and outer drywall  2025   a ,  2025   b ,  105   a ,  105   b  can be any suitable board such as gypsum-based boards and/or cellulose fiberboards, as described herein. 
     Example Methods for Installing Flooring with Isolation Boards 
       FIG.  21    illustrates a flow chart of an example method  2100  for installing floor isolation boards and a cementitious product. The method  2100  can be used to install the flooring  1500  described herein with reference to  FIG.  15   , for example, but may also be used to install the flooring of any of  FIGS.  1 - 13   . 
     Prior to installing the underlayment layer and the isolation boards, a worker can ensure the installation area is swept and clean of debris throughout corners and center. The substrate (e.g., subfloor) can be inspected for delamination and excessive sagging prior to installation of the isolation boards. In addition, the worker can confirm the overall thickness of the underlayment, and specifically the targeted thickness of the cementitious product. The structural barrier formed by the isolation board should be configured to achieve the targeted thickness of the cementitious product. The isolation boards are fire-rated and/or sound-rated. The worker may also measure wall length or targeted length and pre-cut the isolation boards to the measured length. In addition, the worker may place the isolation boards on top of the subfloor, pushing firmly against wall to evaluate and to confirm panel placement. 
     At block  2105 , a worker secures floor isolation boards to the subfloor in a targeted area. The targeted area is located within a first portion of the subfloor where the cementitious product will not be poured. The worker can secure the floor isolation boards to the subfloor so that there is a gap between adjacent isolation boards and any walls. The worker can secure the floor isolation boards to the subfloor using one or a combination of adhesives and mechanical fasteners. If multiple layers of floor isolation boards are to be used, the worker can then install a second layer of the floor isolation boards. In this way, the height of the isolation boards can be built up to a targeted or desired height. The targeted area of the subfloor can include areas such as cabinets, closets, bathtubs, areas near walls and/or other dead spaces are to be set. In some embodiments, the worker can place caulking and/or isolating foam at all pipe penetrations or other penetrations. 
     In some embodiments, the worker lays out the floor isolation boards running parallel to the walls of the room and pushes the boards tight against the base plate of the wall. The worker can then dry fit the isolation boards on each wall using a cabinetry square to account for a gap between each board of no more than about 0.125 in. The worker then applies a bonding adhesive in an S-shaped pattern, for example, to the subfloor and/or to the isolation boards (as described elsewhere herein). The worker can then even out the adhesive material using a trowel, for example. After application and smoothing of the adhesive, the worker can flip the isolation boards and install adhesive side down. The worker can then fasten the isolation boards to the subfloor using 0.080 ring shank coil nails in an offset pattern at about 18 in. on center and no less than about 1 in. from any exposed edge. This can be repeated for areas to cabinetry or other designated areas (e.g., under bathtubs). 
     At block  2110 , the worker installs a sound control membrane on an area of the subfloor not covered by the floor isolation boards. The worker can unroll and lay loose the sound control membrane (e.g., in strips) across the subfloor. Where the sound control membrane is made up of multiple pieces, the worker can seam the pieces of mat together using mechanical fasteners (e.g., zip strips), adhesives, and/or tape. The worker can seam the pieces together at the ends of the sound control membrane using a bonding tape, for example. In some embodiments, after installation of the sound control membrane, the worker should not allow further penetrations to be made in the subfloor as it may degrade the quality of sound control provided by the membrane. The sound control membrane can be installed on a portion of a second area of the subfloor, wherein the subfloor is made up of the first area (covered by the floor isolation boards) and the second area (the portion of the subfloor not covered by the floor isolation boards). 
     At block  2115 , the worker applies a tape material at a transition between the sound control membrane and the floor isolation boards. The tape material can be a bonding tape, for example. In some embodiments, the tape material can be applied so that it covers a portion of the face of the isolation board and a portion of the sound control membrane. In some embodiments, the height covered by the tape material on the face of the isolation boards is about the same as the distance covered on the sound control membrane (e.g., about 1 in. on the face of the isolation board and about 1 in. on the sound control membrane). 
     At block  2120 , the worker pours a cementitious product over the subfloor and the sound control membrane in a second area to a targeted height, such as level with a top side of the floor isolation boards. This is done to create an even and level underlayment. The method  1800  may also include applying sealant to seams between the boards and the cementitious product. This can be done to enhance the levelness of the underlayment. Once the flooring system has been installed using the method  2100 , construction schedule may commence with installations such as drywall, cabinets, and trim as early as within 24 hours after the final pour. 
       FIG.  22    illustrates a flow chart of an example method  2200  for installing floor and wall isolation boards and a cementitious product. The method  2200  can be used to install the flooring  1600  described herein with reference to  FIG.  16   , for example. For steps that are similar to the method  2100 , description will refer to that corresponding step rather than repeating the description. For example, prior to installing the underlayment layer and the isolation boards, a worker can prepare the area as described herein with reference to the method  1400  and the method  2100 . 
     At block  2205 , the worker secures the wall isolation boards to the wall frame using mechanical fasteners. The wall isolation boards can be installed in a manner similar to the floor isolation boards, but against the wall frame rather than on the subfloor. 
     At block  2210 , the worker secures floor isolation boards to the subfloor so that at least a portion of the floor isolation boards are adjacent to the wall isolation boards. Installation of the floor isolation boards is similar to the step  2105  of the method  2100 . 
     In some embodiments, for steps  2205  and  2210 , the worker lays out the floor isolation boards running parallel to the walls of the room and pushed tight against the base plate of the wall with the length side down. The worker then lays out the wall isolation boards running parallel to the walls of the room with the length side up and pushed tight against the base plate of the wall. The worker then fastens the wall isolation boards to the studs of the wall frame and sill plate along the base of the wall, for example, using 1.25 in. drywall screws and 2 screws to each stud. The worker then dry fits the floor isolation boards on each wall using a cabinetry square to account for a gap between each board of no more than about 0.125 in. The worker then applies a bonding adhesive (e.g., using a caulking gun) in an S-shaped pattern on the floor isolation boards. The worker then evens out the adhesive material (e.g., using a trowel). The worker then flips the floor isolation board and installs the boards glue side down. The worker then fastens the floor isolation boards to the subfloor using 0.080 ring shank coil nails in an offset pattern at about 18 in. on center with no less than about 1 in. from any exposed edge. These steps can be repeated for each designated area (e.g., areas that receive cabinets, bathtubs, etc.). 
     At block  2215 , the worker installs a sound control membrane on an area of the subfloor not covered by the floor isolation boards. Installation of the sound control membrane is similar to the step  2110  of the method  2100 . 
     At block  2220 , the worker applies a tape material at a transition between the sound control membrane and the floor isolation boards. Installation of the tape material is similar to the step  2115  of the method  2200 . 
     At block  2225 , the worker pours a cementitious product over the subfloor and the sound control membrane in a second area to a targeted height, such as level with a top side of the floor isolation boards. Pouring the cementitious product is similar to the step  2120  of the method  2100 . In some embodiments, the height of the cementitious product is higher than the height of the floor isolation boards and the cementitious product contacts the wall isolation boards. The height of the cementitious product can be controlled so that it reaches the targeted height by using a height-specific screed darby, for example. 
       FIG.  23    illustrates a flow chart of an example method  2300  for installing wall isolation boards and a cementitious product. The method  2300  can be used to install the flooring  1700  described herein with reference to  FIG.  17   , for example. For steps that are similar to the method  2100 , description will refer to that corresponding step rather than repeating the description. For example, prior to installing the underlayment layer and the isolation boards, a worker can prepare the area as described herein with reference to the method  1400  and the method  2100 . 
     At block  2305 , the worker secures the wall isolation boards to the wall frame using mechanical fasteners. The wall isolation boards can be installed in a manner similar to the floor isolation boards, but against the wall frame rather than on the subfloor. 
     In some embodiments, the worker lays out the wall isolation boards running parallel to the walls of the room with the length side up and pushed tight against the base plate of the wall. The worker then fastens the wall isolation boards to the studs of the wall frame and sill plate along the base of the wall, for example, using 1.25 in. drywall screws and 2 screws to each stud. 
     At block  2310 , the worker installs an isolation strip to a portion of the wall isolation boards. The isolation strip can be installed so that a bottom portion is in contact with or near the subfloor. The isolation strip can be tacked to the wall isolation board. In some embodiments, adhesives may be used in addition to or in place of mechanical fasteners such as tacks. The isolation strip can extend partially up the wall isolation board. For example, the isolation strip can extend about 4 in. up the wall isolation board. Other heights may be used as well. In some embodiments, the tacks can be placed in the top 2 in. of the isolation strip. 
     At block  2315 , the worker installs a sound control membrane on an area of the subfloor. Installation of the sound control membrane is similar to the step  2110  of the method  2100 . 
     At block  2320 , the worker applies a tape material at a transition between the sound control membrane and the isolation strip. Installation of the tape material is similar to the step  2115  of the method  2100 , replacing the floor isolation board with the isolation strip. 
     At block  2325 , the worker pours a cementitious product over the subfloor and the sound control membrane to a targeted height. Pouring the cementitious product is similar to the step  2120  of the method  2100 . In some embodiments, the height of the cementitious product is lower than the height of the isolation strip. The height of the cementitious product can be controlled so that it reaches the targeted height by using a height-specific screed darby, for example. 
       FIG.  24    illustrates a flow chart of an example method  2400  for installing isolation boards and a cementitious product to provide water-control features. The method  2400  can be used to install any of the flooring  1800  or  1900  described herein with reference to  FIGS.  18  and  19   , for example. For steps that are similar to the method  2100 , description will refer to that corresponding step rather than repeating the description. For example, prior to installing the underlayment layer and the isolation boards, a worker can prepare the area as described herein with reference to the method  1400  and the method  2100 . 
     At block  2405 , a worker installs isolation boards. The isolation boards can include wall isolation boards and floor isolation boards forming an ‘L’ flashing detail, as described in  FIG.  18   , or just wall isolation boards, as described in  FIG.  19   . 
     At block  2410 , the worker applies a waterproof layer to the isolation boards. The waterproof coating can be similar to the waterproof coating  1822  described herein with respect to  FIG.  18   . The waterproof coating can be applied in multiple stages. For example, first the worker can coat the isolation boards with a waterproof resin. Then the worker can optionally install a fiberglass or other material over the resin to provide additional support. The waterproof layer can extend onto the subfloor covering the seam between the isolation boards and the subfloor. In some embodiments, the waterproof layer can extend over a floor isolation board and onto a wall isolation board, thereby covering the seam between these boards. In some embodiments, the waterproof layer extends from the subfloor and at least partially up the wall isolation board, at or above the level of the cementitious product that is to be poured. 
     At block  2415 , the worker pours a cementitious product over the subfloor to a targeted height. Pouring the cementitious product is similar to the step  2120  of the method  2100 . In some embodiments, the height of the cementitious product is lower than the height of the waterproof layer. The height of the cementitious product can be controlled so that it reaches the targeted height by using a height-specific screed darby, for example. 
     In some embodiments, the method  2400  can also include elements of the other methods described herein. For example, the method  2400  may also including the installation of a sound control membrane with associated tape. As another example, the method  2400  may also include installing an isolation strip to the wall isolation board. 
     Example Performance Metrics 
     The following includes tables summarizing testing results of various underlayment configurations. The tables indicate hybrid underlayment systems, as disclosed herein, enhance sound control over cementitious product or fiberboards alone. 
     The tests include (2) Normalized Noise Isolation Class (NNIC) and ten (10) Normalized Impact Sound Rating (NISR) tests to evaluate the airborne and impact sound isolation of the floor ceiling assembly between units. The tests were performed in strict accordance with ASTM standard E336, “Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings” and ASTM standard E1007, “Standard Test Method for Field Measurement of Tapping Machine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support Structures”. The tests also included the impact isolation class rating (IIC) based on ASTM testing protocol E492.90 and E989.89. Impact Insulation Class rating or IIC rating can be used by architects, builders and code authorities for acoustical design purposes in building construction. The greater the IIC rating, the lower the impact sound transmission through the floor-ceiling assembly. The sound transmission classification (STC) value was obtained using ASTM testing protocol E90-97 and E413-87. Low Frequency Impact Rating (LIR), which defines the thudding on a floor. High Frequency Impact Rating (NHIR), which defined the high frequency impact isolation (like high heels, animal nails, etc. on the floor). Both of these are important in defining acoustical performance. 
     Results based on floor-ceiling testing are shown in Table 1. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Test Specimen 
                 NNIC 
                 NISR 
                 LIR 
                 NHIR 
               
               
                   
               
             
            
               
                 Living Room to Garage  
                 — 
                 40 
                 51 
                 39 
               
               
                 (hybrid system, 6″ perimeter) 
                   
                   
                   
                   
               
               
                 Kitchen to Garage (hybrid system, 
                 — 
                 45 
                 42 
                 45 
               
               
                 fiberboards under cabinet areas) 
                   
                   
                   
                   
               
               
                 Bedroom 3 to Garage (gypsum concrete) 
                 — 
                 42 
                 53 
                 41 
               
               
                 Bedroom 3 closet to garage (fiberboard) 
                 — 
                 43 
                 52 
                 54 
               
               
                 Bedroom 1 to Garage (gypsum concrete) 
                 — 
                 40 
                 60 
                 39 
               
               
                 Bedroom 1 closet to garage (fiberboard) 
                 — 
                 46 
                 59 
                 60 
               
               
                 Master Bedroom to Garage  
                 — 
                 39 
                 47 
                 38 
               
               
                 (gypsum concrete) 
                   
                   
                   
                   
               
               
                 Master Bedroom to Garage (fiberboard) 
                 — 
                 42 
                 55 
                 53 
               
               
                 Bedroom 3 to Garage  
                 — 
                 44 
                 49 
                 43 
               
               
                 (gypsum concrete area only) 
                   
                   
                   
                   
               
               
                 Bedroom 3 to Garage 
                 — 
                 42 
                 59 
                 51 
               
               
                 (fiberboard area only) 
                   
                   
                   
                   
               
               
                 Living room and kitchen to garage  
                 39 
                 — 
                 — 
                 — 
               
               
                 (gypsum concrete) 
                   
                   
                   
                   
               
               
                 Bedrooms Area (hybrid system) 
                 42 
                 — 
                 — 
                 — 
               
               
                   
               
            
           
         
       
     
     Three subfloor systems were tested over a wood structure with a direct attached ceiling and batt insulation in the stud cavities. The systems were: 1″ thick gypsum concrete throughout, 1″ thick gypsum concrete with a border of fiberboards (i.e., the hybrid underlayment described herein), and fiberboards alone. Floor finishes were not installed at the time of the test. The average impact ratings for each subfloor system are summarized in Table 2. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 System 
                 Average NISR 
                 Average LIR 
                 Average NHIR 
               
               
                   
               
             
            
               
                 Gypsum concrete 
                 41 
                 51 
                 41 
               
               
                 Gypsum concrete  
                 43 
                 47 
                 42 
               
               
                 with fiberboard 
                   
                   
                   
               
               
                 Fiberboard 
                 43 
                 56 
                 54 
               
               
                   
               
            
           
         
       
     
     The testing revealed similar performance between the gypsum concrete system and the hybrid system. The hybrid system (primarily in closets and under tubs) was found be significantly better at reducing high frequency impact sounds. The NHIR rating of the fiberboards alone was 13 points better than the gypsum concrete system, which is related to the material properties associated with the fiberboards that damp the high frequency sounds, which is not accomplished by gypsum concrete; which is expected. The fiberboards show an increase (amplification) in sound levels between 100 and 400 Hz, but this did not affect the ratings and is also expected from these systems. 
     TERMINOLOGY AND ADDITIONAL EMBODIMENTS 
     The present disclosure describes various features, no single one of which is solely responsible for the benefits described herein. It will be understood that various features described herein may be combined, modified, or omitted, as would be apparent to one of ordinary skill. Other combinations and sub-combinations than those specifically described herein will be apparent to one of ordinary skill and are intended to form a part of this disclosure. Various methods are described herein in connection with various flowchart steps and/or phases. It will be understood that in many cases, certain steps and/or phases may be combined such that multiple steps and/or phases shown in the flowcharts can be performed as a single step and/or phase. Also, certain steps and/or phases can be broken into additional sub-components to be performed separately. In some instances, the order of the steps and/or phases can be rearranged and certain steps and/or phases may be omitted entirely. Also, the methods described herein are to be understood to be open-ended, such that additional steps and/or phases to those shown and described herein can also be performed. 
     Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” The word “coupled”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list. The word “exemplary” is used exclusively herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. 
     The disclosure is not intended to be limited to the implementations shown herein. Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. The teachings of the invention provided herein can be applied to other methods and systems and are not limited to the methods and systems described above, and elements and acts of the various embodiments described above can be combined to provide further embodiments. Accordingly, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.